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Arahman, Nasrul, Bastian Arifin e Fachrul Razi. "Profil Permeabilitas Berdasarkan Struktur Morfologi Membran Polietersulfon pada Pemekatan Larutan Tokoferol (Permeability Profile based on Morphology Structure of Polyethersulfone Membrane on Concentrating the Tocopherol Solution)". Agritech 36, n. 4 (25 febbraio 2017): 416. http://dx.doi.org/10.22146/agritech.16765.
Testo completoAbstract (sommario):
Separation technique by membrane technology has been widely applied for separation and purification of minor components from vegetable oil. Membrane was prepared and modified in several way in order to improve the filtration performance in purification process of vegetable oil. In this work, the filtration performance of three types of polyethersulfone hollow fiber membrane was investigated. The main objective of this research was to study the effect of membranes type on the filtration performance of tocopherol solution. Three series of filtration experiment were conducted by using fabricated membrane by dissolving of polyethersulfone (PES) in N-methyl pyrrolydone (NMP) with different polymer composition. The membranes was M1 = PES 20 % + NMP, M2 = PES 18 % + NMP, and M3= PES 20 %+ Polyvinyl pyrrolidone (PVP 5 %) + NMP. The difference structure of membrans was confirmed by scanning electron microscopy measurement. The permeability profile of tocopherol solution of 500 ppm was observed by using a single module of hollow fiber membrane with filtration flow of pressure driven inside (PDI). It is shown that, the permeability of tocopherol solution was maximum and stable using PES membrane was composed by M3 system. Moreover, the improvement of tocopherol concentration in retentate solution was about two times higher than that the original solution that was obtained from filtration system of M1 membrane.ABSTRAKTeknik separasi dengan membran teknologi telah diaplikasikan secara luas untuk pemisahan dan pemurnian komponen minor dari minyak tumbuh-tumbuhan. Membran telah dibuat dan dimodifikasikan dengan berbagai cara untuk meningkatkan kinerja filtrasi pada proses pemurnian minyak tumbuh-tumbuhan. Pada penelitian ini, dipelajari kinerja filtrasi tiga jenis membran hollow fiber yang terbuat dari polimer polietersulfon. Tujuan utama penelitian adalah untuk melihat pengaruh jenis membran terhadap kinerja filtrasi larutan tokoferol. Tiga seri penelitian ultrafiltrasi telah dirancang dengan menggunakan membran yang dibuat dengan melarutkan polietersulfon (PES) dalam N-metil pirolidon (NMP) dengan komposisi polimer yang berbeda. Ketiga jenis membran yang digunakan adalah M1 = PES 20 % + NMP, M2 = PES 18 % + NMP, dan M3 = PES 20 % + Polivinil pirolidon (PVP 5 %) + NMP. Perbedaan struktur morfologi membran telah dikonfirmasikan dengan analisis scanning electron microscopy. Profil permeabilitas larutan tokoferol 500 ppm diobservasi menggunakan modul tunggal membran hollow fiber dengan tipe aliran pressure driven inside (PDI). Hasil penelitian menunjukkan bahwa permeabilitas larutan tokoferol tertinggi dihasilkan dengan menggunakan membran M3. Lebih lanjut, peningkatan konsentrasi larutan tokoferol sekitar dua kali lebih tinggi dari konsentrasi awal dicapai dari proses filtrasi dengan membran M1.
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Maslahat, Mamay, e Agung Abadi Kiswandono. "STUDI TRANSPOR SENYAWA FENOL MENGGUNAKAN MEMBRAN CAIR POLIEUGENOL DENGAN PELARUT DIKLOROMETANA". Jurnal Sains Natural 1, n. 2 (25 novembre 2017): 145. http://dx.doi.org/10.31938/jsn.v1i2.24.
Testo completoAbstract (sommario):
Study on Phenol Compound Transport using Polieugenol Liquid Membrane with Dichloromrthane Solven Phenol is a component in waste water that is very dangerous, because it is toxic, corosif on skins and carcinogenics. It can be separated by using liquid membranes. Membrane can be a very specific filter. Liquid membrans transport technique used three phase. The phase are donor phase that contain substance to be separated, membrane phase that contains ligan in the organic solvents, and aceptore phase that contain base as release agent of ligans complex. Polyeugenol have a condition as a ligan that is capable as selective chelate agent for phenol coumpounds. In this research, polieugenol were used with dichloromethane solvents as a membrane for separating and transporting phenol separated, NaOH as release phase with variating pHs, concentrations of release phase, transport time and membrane concentrations. The result showed that liquid membrane of polieugenol in dichloromethane solvent can transport phenol at source phase pH 6.5, at optimum released concentration was 0.75 M, optimum transport times was 72 hours, and optimum membran concentrations was 1,5×10-3 with % transport was 65.2%.Keywords : Liquid membrane, polyeugenol, dichlorometane, phenol ABSTRAK Fenol merupakan salah satu komponen dalam air limbah yang sangat berbahaya, karena beracun dan bersifat korosif terhadap kulit serta karsinogenik. Fenol dapat dipisahkan dengan menggunakan membran cair. Membran dapat bertindak sebagai filter yang sangat spesifik. Teknik transpor membran cair melibatkan tiga fasa yaitu fasa donor, mengandung bahan yang akan dipisahkan, fasa membran berisi ligan dalam pelarut organik dan fasa akseptor yang berisi basa sebagai agen pelepas dari kompleks ligan.Polieugenol mempunyai syarat sebagai ligan sehingga mampu berfungsi sebagai agen pengkhelat yang selektif untuk senyawa fenol. Pada penelitian ini digunakan polieugenol dengan pelarut diklorometana sebagai membran untuk pemisahan dan transpor senyawa fenol, dan NaOH sebagai fasa pelucut dengan memvariasikan pH, konsentrasi fasa pelucut, waktu transpor dan konsentrasi membran. Hasil penelitian menunjukan bahwa membran cair polieugenol dalam pelarut diklorometana dapat mentranspor fenol pada pH fasa sumber optimum 6,5, pada konsentrasi pelucut optimum 0,75 M, waktu transpor optimum 72 jam, dan pada konsentrasi membran optimum 1,5×10-3 dengan % transpor 65,2%.Kata kunci : membran cair, polieugenol, diklorometana, fenol
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As'adah, Anis, e Munasir MUNASIR. "REVIEW : PERFORMA MEMBRAN KOMPOSIT MENGGUNAKAN ALIRAN DEAD-END FILTRATION". Inovasi Fisika Indonesia 12, n. 2 (4 luglio 2023): 92–102. http://dx.doi.org/10.26740/ifi.v12n2.p92-102.
Testo completoAbstract (sommario):
Teknologi berbasis membran merupakan salah satu teknologi pengolahan air yang paling banyak diminati saat ini karena memiliki beberapa manfaat seperti konsumsi energi yang begitu relatif rendah dan operasi yang sederhana. Membran Graphene Oxide (GO) termasuk membran yang banyak diminati karena memiliki porositas GO yang tinggi serta ukuran pori nano yang baik. Sehingga dilakukan review artikel tentang performa membran komposit menggunakan aliran dead-end filtration. Bahan-bahan lain yang dapat dikompositkan dengan membran GO seperti Ti3C2Tx, Ni, Isophorone Diisocyanate (IPDI), TiO2, Ag, PAM, Attapulgite (ATP) dan SiO2 yang memiliki potensi untuk filtrasi yang berbeda-bedaseperti untuk filtrasi pada pemisahan molekul dan pengolahan air, filtrasi untuk zat pewarna dan lain-lain. Dalam proses filtrasi membran untuk aliran dead-end filtration merupakan aliran yang secara keseluruhannya akan melewati suatu membran serta partikel akan tertahan pada membran tersebut. Pada review artikel ini didapatkan membran komposit GO/SiO2 yang memiliki performa baik dilihat dari nilai fluks tertinggi sebesar 229.15 L/m2.h.bar di antara membran komposit yang lain dan berpotensi untuk filtrasi pencemaran air.
Kata Kunci: Membran Komposit, Graphene Oxide, Dead-End Filtration
Abstract
Membrane-based technology is one of the most popular water treatment technologies today because it has several benefits such as relatively low energy consumption and simple operation. Graphene Oxide (GO) membranes are among the membranes that are in great demand because they have high GO porosity and good nano pore sizes. Therefore, a review of articles on the performance of composite membranes using dead-end filtration was carried out. Other materials that can be composited with GO membranes such as Ti3C2Tx, Ni, Isophorone Diisocyanate (IPDI), TiO2, Ag, PAM, Attapulgite (ATP) and SiO2 which have different potential for filtration such as for filtration in molecular separation and water treatment , filtration for dyes and others. In the membrane filtration process for dead-end filtration flow is a flow that as a whole will pass through a membrane and the particles will be stuck on the membrane. In this review article, it was found that the GO/SiO2 composite membrane had good performance in terms of the highest flux value of 229.15 L/m2.h.bar among other composite membranes and has the potential to filter water pollution.
Keywords: Composite Membrane, Graphene Oxide, Dead-End Filtration
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Efome, Johnson E., Fan Yang, Dipak Rana, Takeshi Matsuura e Christopher Lan. "Functionalized PVDF Nanofiber Membranes for Desalination by Direct Contact Membrane Distillation". International Journal of Materials Science and Engineering 6, n. 2 (giugno 2018): 67–71. http://dx.doi.org/10.17706/ijmse.2018.6.2.67-71.
Testo completo
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Notriawan, Doni, Nesbah Nesbah, Gustria Ernis, Muhammad Adeng Fadhila, Risky Hadi Wibowo, Reza Pertiwi e Vinolla Ilfanisari. "Aktivitas Antibakteri Membran Nanokomposit Kitosan/Nanopartikel Perak". ALCHEMY 9, n. 1 (30 marzo 2021): 26–31. http://dx.doi.org/10.18860/al.v9i1.11146.
Testo completoAbstract (sommario):
The aim of this study was to make and test the antibacterial activity of chitosan/silver nanoparticles nanocomposite membranes. Nanocomposite membranes were synthesized by chitosan with pluronic using acetic acid as a solvent. Silver nanoparticles were synthesized using the green synthesis method and the makasar fruit (Brucea javanica L. Merr) peel extract as a bioreductor. The silver nanoparticles were composited with a chitosan/pluronic mixture and printed on a glass plate. Nanocomposite membranes were characterized using the FTIR spectrophotometer and the scanning electron microscope (SEM). Nanocomposite membrane were tested for antibacterial activity against Escherechia coli. The UV-Vis spectra showed the formation of silver nanoparticles which were indicated by the absorption at 454 nm and the absorbance value of 0.405. Characterization using FTIR showed no new functional groups formed in the composites of chitosan and pluronic. SEM results showed the difference between the chitosan membrane and the nanocomposite membrane. The surface of nanocomposite membrane showed uneven compared to the chitosan membrane. Nanocomposite membranes have antibacterial activity to inhibit E. coli growth. Keywords: nanocomposite, chitosan/silver nanoparticles, antibacterial Penelitian ini bertujuan untuk membuat dan menguji aktivitas antibakteri membran nanokomposit kitosan/nanopartikel perak. Membran nanokomposit dibuat dengan mensintesis kitosan dengan pluronik menggunakan pelarut asam asetat. Nanopartikel perak disintesis menggunakan metode green synthesis dengan ekstrak kulit buah makasar (Brucea javanica L. Merr) sebagai bioreduktor. Nanopartikel perak dikompositkan dengan campuran kitosan/pluronik dan dicetak di atas plat kaca. Membran nanokomposit dikarakterisasi menggunakan spektrofotometer FTIR dan scanning electron microscope (SEM). Membran nanokomposit dilakukan uji aktivitas antibakteri terhadap Escherechia coli. Spektra UV-Vis menunjukkan terbentuknya nanopartikel perak yang ditandai adanya serapan pada panjang gelombang 454 nm dan absorbansi 0,405. Karakterisasi dengan FTIR menunjukkan tidak adanya gugus fungsi baru yang terbentuk pada komposit dari kitosan dan pluronik. Hasil SEM menunjukkan adanya perbedaan antara membran kitosan dengan membran nanokomposit. Permukaan membran nanokomposit terlihat tidak rata dibandingkan membran kitosan. Membran nanokomposit memiliki aktivitas bakteri sehingga dapat mengambat pertumbuhan bakteri E. coli. Kata kunci: nanokomposit, kitosan/nanopartikel perak, antibakteri
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Indriyani, Vera, Yunita Novianty e Agus Mirwan. "PEMBUATAN MEMBRAN ULTRAFILTRASI DARI POLIMER SELULOSA ASETAT DENGAN METODE INVERSI FASA". Konversi 6, n. 1 (1 aprile 2017): 11. http://dx.doi.org/10.20527/k.v6i1.2994.
Testo completoAbstract (sommario):
Abstrak- Pengolahan air bersih dengan teknologi membran merupakan proses pengolahan air dengan kualitas yang sangat baik dan sesuai untuk pengolahan air minum di negara-negara berkembang karena membran memiliki banyak sekali keunggulan. Salah satu jenis operasi pemisahan membran adalah dengan membran ultrafiltrasi. Ultrafiltrasi merupakan proses penyaringan partikel-partikel dalam rentang ukuran koloid, yaitu larutan dan molekul besar ditahan dipermukaan membran dan zat terlarut dengan ukuran sangat kecil dapat melewati membran. Tujuan dari penelitian ini adalah untuk menentukan komposisi % berat dimetilformamida pada pembuatan membran ultrafiltrasi yang terbaik. Membran ultrafiltrasi ini dibuat dengan memvariasikan konsentrasi aditif dimetilformamida yang berfungsi untuk penentuan ukuran pori membran dan konsentrasi aseton. Pencampuran bahan dilakukan dengan pengadukan selama ± 6 jam, hasil cetakan film polimer dikoagulasi selama 1 jam dalam air es (± 4°C) kemudian dicuci dengan air mengalir dan disimpan dalam wadah yang diberi formalin. Kemudian dilakukan pengujian pada membran tersebut menggunakan air gambut dimana permeat yang dihasilkan di ukur volumenya setiap selang waktu 5 menit untuk menentukan fluks membrannya. Kemudian dilakukan analisa terhadap konsentrasi permeat untuk menentukan koefisien rejeksi, di mana rejeksi yang diharapkan adalah > 90%. Berdasarkan hasil penelitian, membran ultrafiltrasi yang terbaik adalah membran dengan komposisi % berat dimetilformamida 20; 24 dan 28 dimana koefisien rejeksi rata-rata yang diperoleh masing-masing adalah 98,15; 92,80 dan 95,41%. Kata kunci: dimetilformamida, koefisien rejeksi, fluks Abstract-Clean water treatment with membrane technology is a water treatment process with very good quality and suitable for drinking water treatment in developing countries because the membrane has a lot of advantages. One type of membrane separation operation is with ultrafiltration membranes. Ultrafiltration is a process of filtering particles in the size range of colloids, namely liquid while large molecules detained on the surface of the membrane and the solute with very small size can pass through the membrane. The purpose of this study was to determine the best composition of %wt of dimethylformamide in the manufacture of ultrafiltration membranes. Ultrafiltration membrane is made by varying the concentration of the additive of dimethylformamide which serves for the determination of membrane pore size and the concentration of acetone. Mixing materials done by stirring for ± 6 hours, polymer film printouts is coagulated for 1 hour in ice water (± 4 ° C) and then washed with running water and stored in a container containing formalin. Then conducted testing on the membrane using peat water where permeate that generated is measured the volume of each interval of 5 minutes to determine the membrane flux. Then analyzing the concentration of permeate to determine the coefficient of rejection, where the expected rejection is> 90%. Based on the research results, the best ultrafiltration membrane was membrane with composition wt% of dimethylformamide of 20; 24 and 28, where rejection coefficient average respectively was 98.15; 92.80 and 95.41%. Keywords: dimethylformamide, rejection coefficient, flux
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Mirwan, Agus, Vera Indriyani e Yunita Novianty. "PEMBUATAN MEMBRAN ULTRAFILTRASI DARI POLIMER SELULOSA ASETAT DENGAN METODE INVERSI FASA". Konversi 6, n. 1 (28 marzo 2018): 11. http://dx.doi.org/10.31213/k.v6i1.14.
Testo completoAbstract (sommario):
Abstrak- Pengolahan air bersih dengan teknologi membran merupakan proses pengolahan air dengan kualitas yang sangat baik dan sesuai untuk pengolahan air minum di negara-negara berkembang karena membran memiliki banyak sekali keunggulan. Salah satu jenis operasi pemisahan membran adalah dengan membran ultrafiltrasi. Ultrafiltrasi merupakan proses penyaringan partikel-partikel dalam rentang ukuran koloid, yaitu larutan dan molekul besar ditahan dipermukaan membran dan zat terlarut dengan ukuran sangat kecil dapat melewati membran. Tujuan dari penelitian ini adalah untuk menentukan komposisi % berat dimetilformamida pada pembuatan membran ultrafiltrasi yang terbaik. Membran ultrafiltrasi ini dibuat dengan memvariasikan konsentrasi aditif dimetilformamida yang berfungsi untuk penentuan ukuran pori membran dan konsentrasi aseton. Pencampuran bahan dilakukan dengan pengadukan selama ± 6 jam, hasil cetakan film polimer dikoagulasi selama 1 jam dalam air es (± 4°C) kemudian dicuci dengan air mengalir dan disimpan dalam wadah yang diberi formalin. Kemudian dilakukan pengujian pada membran tersebut menggunakan air gambut dimana permeat yang dihasilkan di ukur volumenya setiap selang waktu 5 menit untuk menentukan fluks membrannya. Kemudian dilakukan analisa terhadap konsentrasi permeat untuk menentukan koefisien rejeksi, di mana rejeksi yang diharapkan adalah > 90%. Berdasarkan hasil penelitian, membran ultrafiltrasi yang terbaik adalah membran dengan komposisi % berat dimetilformamida 20; 24 dan 28 dimana koefisien rejeksi rata-rata yang diperoleh masing-masing adalah 98,15; 92,80 dan 95,41%. Kata kunci: dimetilformamida, koefisien rejeksi, fluks Abstract-Clean water treatment with membrane technology is a water treatment process with very good quality and suitable for drinking water treatment in developing countries because the membrane has a lot of advantages. One type of membrane separation operation is with ultrafiltration membranes. Ultrafiltration is a process of filtering particles in the size range of colloids, namely liquid while large molecules detained on the surface of the membrane and the solute with very small size can pass through the membrane. The purpose of this study was to determine the best composition of %wt of dimethylformamide in the manufacture of ultrafiltration membranes. Ultrafiltration membrane is made by varying the concentration of the additive of dimethylformamide which serves for the determination of membrane pore size and the concentration of acetone. Mixing materials done by stirring for ± 6 hours, polymer film printouts is coagulated for 1 hour in ice water (± 4 ° C) and then washed with running water and stored in a container containing formalin. Then conducted testing on the membrane using peat water where permeate that generated is measured the volume of each interval of 5 minutes to determine the membrane flux. Then analyzing the concentration of permeate to determine the coefficient of rejection, where the expected rejection is> 90%. Based on the research results, the best ultrafiltration membrane was membrane with composition wt% of dimethylformamide of 20; 24 and 28, where rejection coefficient average respectively was 98.15; 92.80 and 95.41%. Keywords: dimethylformamide, rejection coefficient, flux
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Noezar, I. "Membran PVA-chitosan crosslinked untuk pemisahan campuran etanol-air secara pervaporasi". Jurnal Teknik Kimia Indonesia 7, n. 1 (9 ottobre 2018): 724. http://dx.doi.org/10.5614/jtki.2008.7.1.3.
Testo completoAbstract (sommario):
One of the technologies for ethanol-water separation is pervaporation. The principles of pervaporation is based on the difference in diffusional rate and solubility of the solution components in membranes. The performance of the membrane, in terms of flux and selectivity, is influenced by the swelling of the membrane due to the interaction between the solution components and the membrane materials. Membrane modification is done by forming chemical bonding between PVA and chitosan, using glutaraldehyde as crosslinking agent. The performance of the PVA-chitosan crosslinked membrane for ethanol-water separation is characterized by high mass flux and reasonably high selectivity. Pressure observed on the permeate side was 0.5 mbar, with a feed ethanol concentration of 93%. Experimental results indicate that the PVA membrane has a higher degree of swelling compared to the crosslinked PVA-chitosan membrane. The PVA-chitosan crosslinked membrane has a higher selectivity compared to the PVA membrane. The highest flux of 0.833 kgm-2hour-1 was produced by the PVA membrane. The highest selectivity of 2.820 was obtained using a 1:1 PVA-chitosan crosslinked membrane.Keywords: PVA-chitosan; crosslinked; pervaporation Abstrak Salah satu teknologi untuk pemisahan etanol-air adalah pervaporasi. Prinsip pemisahan pervaporasi adalah dengan perbedaan laju difusi dan kelarutan komponen campuran pada membran. Kinerja membran berupa fluks dan selektivitas dipengaruhi oleh kondisi swelling membran akibat interaksi komponen dengan material membran. Modifikasi membran dilakukan dengan membentuk ikatan kimia antara PVA dan chitosan dengan glutaraldehid sebagai crosslinking agent. Kinerja membran PVA-Chitosan crosslinked dalam pemisahan campuran etanol-air berupa fluks massa yang tinggi dan selektivitas yang cukup besar. Tekanan pada sisi permeat 0,5 mbar dengan konsentrasi etanol umpan 93%. Hasil penelitian menunjukkan membran PVA memiliki nilai derajat swelling lebih tinggi (0,088) daripada membran PVA-Chitosan crosslinked. Membran PVA-Chitosan crosslinked memiliki selektivitas lebih tinggi daripada membran PVA. Fluks terbesar dimiliki oleh membran PVA senilai 0,833 kgm-2jam-1membran PVA-Chitosan crosslinked 1:1 sebesar 2.820.Kata Kunci : PVA-Chitosan; crosslinked; pervaporasi
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Li, Xue, Jun Pan, Francesca Macedonio, Claudia Ursino, Mauro Carraro, Marcella Bonchio, Enrico Drioli, Alberto Figoli, Zhaohui Wang e Zhaoliang Cui. "Fluoropolymer Membranes for Membrane Distillation and Membrane Crystallization". Polymers 14, n. 24 (12 dicembre 2022): 5439. http://dx.doi.org/10.3390/polym14245439.
Testo completoAbstract (sommario):
Fluoropolymer membranes are applied in membrane operations such as membrane distillation and membrane crystallization where hydrophobic porous membranes act as a physical barrier separating two phases. Due to their hydrophobic nature, only gaseous molecules are allowed to pass through the membrane and are collected on the permeate side, while the aqueous solution cannot penetrate. However, these two processes suffer problems such as membrane wetting, fouling or scaling. Membrane wetting is a common and undesired phenomenon, which is caused by the loss of hydrophobicity of the porous membrane employed. This greatly affects the mass transfer efficiency and separation efficiency. Simultaneously, membrane fouling occurs, along with membrane wetting and scaling, which greatly reduces the lifespan of the membranes. Therefore, strategies to improve the hydrophobicity of membranes have been widely investigated by researchers. In this direction, hydrophobic fluoropolymer membrane materials are employed more and more for membrane distillation and membrane crystallization thanks to their high chemical and thermal resistance. This paper summarizes different preparation methods of these fluoropolymer membrane, such as non-solvent-induced phase separation (NIPS), thermally-induced phase separation (TIPS), vapor-induced phase separation (VIPS), etc. Hydrophobic modification methods, including surface coating, surface grafting and blending, etc., are also introduced. Moreover, the research advances on the application of less toxic solvents for preparing these membranes are herein reviewed. This review aims to provide guidance to researchers for their future membrane development in membrane distillation and membrane crystallization, using fluoropolymer materials.
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Saputra, Hens. "Pembuatan dan Karakteristik Membran Reaktor Zeolit". Majalah Ilmiah Pengkajian Industri 8, n. 1 (29 luglio 2019): 11–16. http://dx.doi.org/10.29122/mipi.v8i1.3643.
Testo completoAbstract (sommario):
Membran reaktor merupakan konsep perpaduan dari sistem reaksi dan proses pemisahan/pemurnian. Membran ini disebut juga sebagai membran katalis atau sistem katalis-membran. Dengan membran reaktor ini diharapkan konversi suatu reaksi dapat ditingkatkan dan diperoleh suatu produk yang memiliki tingkat kemurnian lebih tinggi. Sebagai katalis digunakan silica alumina yang berukuran 1,0 mm. Membran anorganik zeolit MFI dilapiskan menutupi seluruh permukaan katalis. Bahan baku yang digunakan antara lain tetraethylortosilikat (TEOS) sebagai sumber silikat dan template organik tetraprophyl ammonium bromide (TPABr). Proses kristalisasi dilakukan pada temperatur 453 K di dalam autogeneous autoclave, dilanjutkan dengan kalsinasi pada temperatur 873 K selama 1 jam. Karakterisasi membran zeolit yang dihasilkan dilakukan dengan X-ray diffraction (XRD) dan pengamatan dengan Scanning Electron Mycroscope (SEM). Karakteristik pori dipelajari menggunakan metode physisorption dan BJH pore size distribution. Selain itu dilakukan pula uji selektifitas dan alkilasi toluena dan xylene. Berdasarkan pengamatan menggunakan XRD mengindikasikan adanya struktur zeolit MFI pada sampel membrane katalis yang dihasilkan. Diperkuat dengan obserbasi SEM menunjukkan bahwa membran zeolit MFI melapisi seluruh permukaan pelet silika alumina dan terdapat indikasi terjadinya komposit terhadap silika alumina pada daerah perbatasan antara membran zeolit atau lapisan bagian luar dengan katalis silika alumina. Hasil pengujian menunjukkan hasil bahwa membran reaktor zeolit MFI berpotensi untuk diaplikasikan sebagai membran katalis yang bersifat sangat selektif terhadap bentuk suatu molekul. Sebagai contoh kasus, suatu isomer dapat dipisahkan satu sama lain secara selektif, sehingga dapat meningkatkan konversi reaksi.Kata kunci : Membran reaktor, isomer, xylene, zeolit, silika alumina, hydrothermal.AbstractMembrane fusion reactor is the concept of the reaction system and the process of separation/purification . These membranes are called also as membrane catalysts or catalyst - membrane system . With the membrane reactor is expected conversion reaction can be improved and obtained a product which has a higher degree of purity . As used silica alumina catalyst measuring 1.0 mm . MFI zeolite coated inorganic membranes covering the entire surface of the catalyst . The raw materials used include tetraethylortosilikat (TEOS ) as a source of silicate and organic template tetraprophyl ammonium bromide ( TPABr ) . Crystallization process carried out at a temperature of 453 K in the autogeneous autoclave , followed by calcination at a temperature of 873 K for 1 hour . Characterization of zeolite membranes produced by X - ray done diffraction ( XRD ) and scanning electron observations with Mycroscope ( SEM ) . Pore characteristics studied physisorption using BJH pore size and distribution . Test will be conducted and the selectivity of toluene and xylene alkylation . Based on observations using XRD indicates the MFI zeolite structure on the resulting catalyst membrane samples . Reinforced with obserbasi SEM showed that the MFI zeolite membrane coating the entire surface of the silica- alumina pellets and there are indications of the silica- alumina composite in the border area between the zeolite membrane or outer layer of silica alumina catalyst . The results show that the results of the MFI zeolite membrane reactor has the potential to be applied as the membrane is highly selective catalyst to form a molecule . As an example case , an isomer can be separated from each other selectively , so as to increase the reaction conversionKeywords : Membrane reactors, isomers, xylene, zeolite, silica alumina, hydrothermal.
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Kharisma, Thria, Nina Ariesta e Dian Arrisujaya. "KARAKTERISTIK MEMBRAN KOMPOSIT BERBASIS KITOSAN/PVA TERMODIFIKASI LEMPUNG DARI BABAKAN MADANG BOGOR". Jurnal Sains Natural 10, n. 1 (11 agosto 2020): 33. http://dx.doi.org/10.31938/jsn.v10i1.276.
Testo completoAbstract (sommario):
The use of natural polymers as membranes of DMFC from chitosan was developed because it is more environmentally friendly and has high thermal stability, but the proton conductivity is low. The Clay from Babakan Madang, which contained of SiO2 50% was expected to increase proton conductivity and improve the characteristics of the polymer membrane. Chitosan / PVA based membrane synthesis was carried out by adding clay weight variations of 0.3, 0.6 and 0.9 g. The spectra of membranes investigated by FT-IR confirmed the presence of functional groups from chitosan/PVA/clay. Morphological analysis using SEM showed that there were granules of clay dispersed on the membrane. The determination of membran conductivity using EIS showed the highest proton conductivity value was a membrane with the addition of 0.6 g clay, it was 6.96 x 10-7 S / cm. The membrane water swelling produced on the three membranes tended to be high, with the smallest value of 56.69% on the membrane with the addition of 0.9 grams of clay. The methanol uptake data found that the conductivity of membrane with the addition of 0.6 grams of clay was 346.11%.
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Petrauskas, Karolis. "Kompiuterinis biojutiklių su perforuota ir selektyvia membrana modeliavimas vienmačiu keturių sluoksnių modeliu". Informacijos mokslai 50 (1 gennaio 2009): 328–33. http://dx.doi.org/10.15388/im.2009.0.3217.
Testo completoAbstract (sommario):
Straipsnyje pateikiamas vienmatis biojutiklio su perforuota ir selektyvia membrana modelis. Šis modelis sudarytas pakeičiant perforuotą membraną dviem homogeniškais sluoksniais atitinkamai membranos dalims, kur skylutės yra užpildytos fermento ir kur fermento nėra. Pasiūlytas modelis buvo ištirtas vykdant skaitinius eksperimentus, kad būtų nustatytos sąlygos, kuriomis jis gali būti taikomas tiksliam biojutiklio veiksmo modeliavimui. Šio modelio tikslumas buvo vertinamas lyginant juo gaunamus rezultatus su dvimačio modelio rezultatais. Pasiūlyto modelio rezultatai taip pat buvo palyginti su vienmačio modelio, kuriame perforuota membrana pakeičiama vienu homogenišku sluoksniu, rezultatais. Biojutiklis buvo modeliuojamas reakcijos-difuzijos lygtimis su netiesiniu nariu, aprašančiu fermentinės reakcijos Michaelio–Menteno kinetiką. Modelio lygčių sistema buvo sprendžiama skaitiškai, naudojant baigtinių skirtumų metodą.Computer-Aided Modeling of a Biosensor with Selective and Perforated Membranes Using a Four-Layered One-Dimensional ModelKarolis Petrauskas SummaryThis article presents a one-dimensional model for a biosensor with perforated and selective membranes. This model is constructed by replacing the perforated membrane with two homogeneous layers. These layers are used to model parts of the perforated membrane, where holes are fi lled with an enzyme and where is no enzyme in the holes, separately. The proposed model was investigated by performing numerical experiments in order to determine conditions, under which the proposed model can be used to simulate an operation of a biosensor with an outer perforated membrane precisely. A preciseness of the model was measured by comparing its results with results of the corresponding two-dimensional model. Beside the measurement of the preciseness, results of the proposed model were compared to the results of the one-dimensional model, constructed by replacing the perforated membrane with one homogeneous layer. A biosensor was modeled using diffusion-reaction equations with a nonlinear member representing the Michaelis-Menten kinetic of an enzymatic reaction. These equations were solved numerically, using the method of fi nite differences.: 18px;">
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Burganos, Vasilis N. "Membranes and Membrane Processes". MRS Bulletin 24, n. 3 (marzo 1999): 19–22. http://dx.doi.org/10.1557/s0883769400051861.
Testo completoAbstract (sommario):
Membrane separation science has enjoyed tremendous progress since the first synthesis of membranes almost 40 years ago, which was driven by strong technological needs and commercial expectations. As a result, the range of successful applications of membranes and membrane processes is continuously broadening. An additional change lies in the nature of membranes, which is now extended to include liquid and gaseous materials, biological or synthetic. Membranes are understood to be thin barriers between two phases through which transport can take place under the action of a driving force, typically a pressure difference and generally a chemical or electrical potential difference.An attempt at functional classification of membranes would have to include diverse categories such as gas separation, pervaporation, reverse osmosis, micro- and ultrafiltration, and biomedical separations. The dominant application of membranes is certainly the separation of mixed phases or fluids, homogeneous or heterogeneous. Separation of a mixture can be achieved if the difference in the transport coefficients of the components of interest is sufficiently large. Membranes can also be used in applications other than separation targeting: They can be employed in catalytic reactors, energy storage and conversion systems, as key components of artificial organs, as supports for electrodes, or even to control the rate of release of both useful and dangerous species.In order to meet the requirements posed by the aforementioned applications, membranes must combine several structural and functional properties.
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Böddeker, K. W. "Membranes and Membrane Processes". Journal of Membrane Science 31, n. 2-3 (maggio 1987): 343–44. http://dx.doi.org/10.1016/s0376-7388(00)82238-3.
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Meares, P. "Membranes and membrane processes". Polymer 28, n. 7 (giugno 1987): 1232. http://dx.doi.org/10.1016/0032-3861(87)90271-0.
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Darmani, H., e W. T. Coakley. "Membrane-membrane interactions: parallel membranes or patterned discrete contacts". Biochimica et Biophysica Acta (BBA) - Biomembranes 1021, n. 2 (gennaio 1990): 182–90. http://dx.doi.org/10.1016/0005-2736(90)90032-j.
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Masykur, Abu, Gaby Aprilia, Anggun Duwi Hapsari, Atmanto Heru Wibowo, Candra Purnawan, Sri Hastuti, Pranoto Pranoto e Tri Martini. "Modifikasi Membran Kitosan Tertaut Silang Tripolifosfat Untuk Deteksi Ion Cu(II)". ALCHEMY Jurnal Penelitian Kimia 19, n. 1 (23 marzo 2023): 86. http://dx.doi.org/10.20961/alchemy.19.1.56392.86-93.
Testo completoAbstract (sommario):
<p>Penelitian ini bertujuan untuk memodifikasi kitosan dan digunakan sebagai sensor ion logam Cu(II). Modifikasi dilakukan dengan penaut silang kitosan menggunakan tripolifosfat dan dibentuk menjadi membran. Membran yang dihasilkan dianalisis dengan spektrofotometer UV-Vis, <em>Fourier Transform InfraRed </em>(FTIR), dan <em>Scanning Electron Microscope-Energy Dispersive X-Ray</em> (SEM-EDX). Hasil analisis menunjukkan keberhasilan sintesis membran kitosan/tripolifosfat (CTS/TPP). Membran CTS/TPP dapat mendeteksi ion logam Cu(II) ditandai adanya perubahan warna membran dari bening menjadi biru. Keberhasilan deteksi ion logam Cu(II) oleh membran dikonfirmasi oleh pengujian UV-Vis, FTIR dan SEM-EDX. Pengujian spektrofotometer UV-Vis pada membran setelah dikontakkan dengan ion logam Cu(II) menunjukkan terjadinya pergeseran panjang gelombang maksimum akibat interaksi yang terjadi antara membran dengan ion logam Cu(II). Pada penentuan kondisi optimum pH, membran CTS/TPP optimum bekerja pada pH 7 dalam waktu 15 menit. Pada rentang konsentrasi ion Cu(II) 1‒10 ppm, nilai koefisien korelasi (R<sup>2</sup>) untuk membran CTS/TPP diperoleh sebesar 0,9917.</p><p><strong>Modification of Tripolyphosphate Cross-Linked Chitosan Membrane for Cu(II) Ion Sensor.</strong> This study aims to modify chitosan and use it as a sensor for Cu(II) metal ions. The modification was carried out by cross-linking chitosan using tripolyphosphate and forming it into a membrane. The resulting membranes were analyzed by UV-Vis, FTIR spectrophotometer, and SEM-EDX. The analysis results show the successful synthesis of the chitosan/tripolyphosphate (CTS/TPP) membrane. The CTS/TPP membrane can detect Cu(II) metal ions, as indicated by a change in the color of the membrane from clear to blue. The successful detection of Cu(II) metal ions by the membrane was confirmed by UV-Vis, FTIR spectrophotometer, and SEM-EDX. UV-Vis spectrophotometer testing on the membrane after contact with Cu(II) metal ions showed that the maximum wavelength was shifted due to the interaction that occurred between the membrane and Cu(II) metal ions. In the determination of the optimum pH condition, the CTS/TPP membrane optimally works at pH 7 for 15 minutes. In the Cu(II) concentration range of 1‒10 ppm, the correlation coefficient (R<sup>2</sup>) value for the CTS/TPP membrane was 0.9917.</p>
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Mori, Kenichi, Yosuke Imai, Tsubasa Takaoka, Koji Iwamoto, Hideyoshi Fuji e Tyuji Hoshino. "2P270 Database of Lipid Membrane Structures : Computational Analyses of Model Membranes(40. Membrane structure,Poster Session,Abstract,Meeting Program of EABS & BSJ 2006)". Seibutsu Butsuri 46, supplement2 (2006): S363. http://dx.doi.org/10.2142/biophys.46.s363_2.
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Kim, Hwan, June Seok Choi e Sang Ho Lee. "Effect of Membrane Material Properties on Efficiency of Membrane Distillation". Materials Science Forum 695 (luglio 2011): 85–88. http://dx.doi.org/10.4028/www.scientific.net/msf.695.85.
Testo completoAbstract (sommario):
Membrane distillation (MD) integrates membrane technology with evaporation process to produce fresh water from seawater or contaminated water. In this study, we investigated the effect of membrane materials on the efficiency of membrane distillation process. Flat sheet hydrophobic membranes (PVDF, PTFE) with different characterizes were chosen as well as hollow fiber membranes (PE). Laboratory-scale systems were developed for initial screening of various membranes. The performance of the membrane was analyzed in terms of water permeability and salt rejection. Synthetic seawater (TDS = 35,000 mg/L) was used for the lab-scale tests. A simple model to analyze the transport of water through MD membranes was developed to interpret experimental results. In addition, long-term performances of the membranes were compared to examine the stability of membrane materials and fouling tendency using real seawater. Based on the lab-scale experiments, techniques to improve the performance of the membranes were examined by applying physical and chemical modification.
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Maulina, Wenny, Ismia Khilmi Fauzia e Misto Misto. "KAJIAN MEMBRAN NILON SEBAGAI FILTER PADA PROSES PENJERNIHAN NIRA TEBU". Spektra: Jurnal Fisika dan Aplikasinya 3, n. 1 (30 aprile 2018): 57–66. http://dx.doi.org/10.21009/spektra.031.08.
Testo completoAbstract (sommario):
Abstrak
Membran nilon merupakan lapisan semipermeabel yang terbuat dari jenis polimer poliamida untuk memisahkan partikel tertentu dari larutannya. Pada artikel ini, membran nilon berperan sebagai filter untuk penjernihan nira tebu dengan mengkaji kinerja, efektivitas, dan efisiensi membran. Penelitian dilakukan dengan sistem aliran dead-end pada proses ultrafiltrasi menggunakan empat tekanan transmembran yang berbeda yaitu 1.0, 1.5, 2.0, dan 2.5 bar. Konsentrasi nira tebu sebelum dan sesudah proses ultrafiltrasi dikarakterisasi menggunakan Spektrofotometer UV-Vis. Membran nilon dengan variasi massa 4.5, 5.0, 5.5, 6.0, dan 6.5 gram, menunjukkan fluks air yang sesuai pada rentang 15 – 38 L/m2.jam.bar pada tekanan transmembran. Hasil penelitian menunjukkan bahwa membran nilon yang memiliki kinerja paling baik adalah membran dengan massa benang nilon 4.5 gram karena memiliki nilai fluks paling besar dan nilai koefisien rejeksi paling kecil. Membran dengan massa benang nilon 6.5 gram memiliki efektivitas dan efisiensi penurunan sukrosa yang paling besar. Sedangkan membran dengan massa benang nilon 4.5 gram memiliki efektivitas dan efsiensi penurunan konsentrasi sukrosa yang paling rendah.
Kata-kata kunci: membran nilon, nira tebu, kinerja membran, efektivitas, efisiensi.
Abstract
Nylon membrane is a semipermeable layer made of a type of polyamide polymer to separate certain particles from the solution. In this article, nylon membrane is presented as a filter for clarification of sugarcane juice concerning study on performance evaluation, effectiveness, and efficiency of the membrane. The experiments were conducted according to the principle of the dead-end in an ultrafiltration process using four different transmembrane pressures of 1.0, 1.5, 2.0, and 2.5 bar. The concentration of sugarcane juice before and after ultrafiltration process was characterized using UV-Vis Spectrophotometer. Nylon membranes, which consist of 4.5, 5.0, 5.5, 6.0, and 6.5 gram various mass, showed matched water flux in the range of 15 – 38 L/m2.jam.bar at the transmembrane pressures. The results showed that the best performance nylon membrane was a nylon membrane with a mass of 4.5 gram nylon, because it has the largest flux and the smallest rejection coefficient. Nylon membrane with a mass of 6.5 gram has the biggest effectiveness and efficiency in the reduced of sucrose concentration. Meanwhile, nylon membrane with a mass of 4.5 gram has the lowest effectiveness and efficiency in the reduced of sucrose concentration.
Keywords: nylon membrane, sugarcane, membrane performance, effectiveness, efficiency.
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Alvianto, Dikianur, Fara Aulia Agustin Nurhadi, Angky Wahyu Putranto, Bambang Dwi Argo, Mochammad Bagus Hermanto e Yusuf Wibisono. "Sintesis dan Karakterisasi Membran Selulosa Asetat dengan Penambahan Antibiofouling Alami Ekstrak Bawang Putih". ALCHEMY Jurnal Penelitian Kimia 18, n. 2 (4 settembre 2022): 193. http://dx.doi.org/10.20961/alchemy.18.2.57199.193-204.
Testo completoAbstract (sommario):
<p>Teknologi membran merupakan teknologi yang dapat memisahkan dua fasa (permeat dan umpan). Kendala dalam teknologi membran yaitu bahan yang terkandung dalam umpan dan mengakibatkan terjadinya <em>fouling</em> (penutupan pori). Salah satu alternatif untuk mengurangi <em>fouling</em> yaitu menambahkan zat <em>antibiofouling </em>pada membran. Bahan yang dapat digunakan sebagai antibiofoulan alami adalah ekstrak bawang putih yang memiliki sifat antibakteri. Penelitian ini bertujuan untuk menganalisis pengaruh penambahan ekstrak bawang putih terhadap perbaikan karakteristik membran (ketebalan, kuat tarik, elastisitas), fluks air bersih, dan sifat <em>antibiofouling</em> pada bakteri <em>Bacillus subtilis</em>. Membran selulosa asetat dibuat dengan menggunakan metode inversi fasa dan pelarut dimetilformamida. Penambahan ekstrak bawang putih pada pembuatan membran selulosa asetat memiliki konsentrasi masing-masing sebesar 0,25% b/v (0,01 g), 0,5% b/v (0,02 g), 0,75% b/v (0,03 g), dan 0% b/v (kontrol) dengan ketebalan 0,3 mm. Hasil yang optimum diperoleh untuk membran dengan konsentrasi 0,5 % b/v yang menghasilkan pengujian kuat tarik sebesar 0,977 N/mm<sup>2 </sup>dan untuk membrane dengan konsentrasi 0,25% b/v yang memberikan elastistas pertambahan panjang sebesar 12,22%. Sifat antibakteri membran dengan penambahan ekstrak bawang putih ditunjukkan dengan berkurangnya penempelan bakteri <em>Bacillus subtilis </em>pada permukaan membran sebesar 41,5% – 87,7% area.</p><p><strong>Synthesis and Characterization of Cellulose Acetate Membrane with The Addition of Natural Antibiofouling Garlic Extract<em>.</em></strong><em> </em>Membrane technology is a technology that can separate two phases (permeate and feed). The main problem in membrane technology is the material contained in the feed, which causes fouling (pore closure). An alternative to reducing fouling is by adding anti-biofouling substances into the membrane. The material that can be used as a natural anti-biofoulant is garlic extract which has antibacterial properties. This study aimed to analyze the effect of adding garlic extract on the improvement of membrane characteristics (thickness, tensile strength, elasticity), clean water flux, and anti-biofouling properties of Bacillus subtilis bacteria. The cellulose acetate membrane was synthesized using dimethylformamide as solvent through the phase inversion method. The addition of garlic extract in the manufacture of cellulose acetate membranes had concentrations of 0.25% w/v (0.01 g), 0.5% w/v (0.02 g), 0.75% w/v (0.03 g), and 0% w/v (control) with a thickness of 0.3 mm. The optimum results were obtained for the membrane with a concentration of 0.5% w/v, which resulted in the tensile strength test of 0.977 N/mm<sup>2</sup>, and the membrane with a concentration of 0.25% w/v, which resulted in an elongation elasticity of 12.22%. The antibacterial properties of membranes with the addition of garlic extract were indicated by the adhesion reduction of <em>Bacillus subtilis</em> bacteria on the membrane surface by 41.5% – 87.7% area.</p>
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Baumgart, E., A. Völkl, T. Hashimoto e H. D. Fahimi. "Biogenesis of peroxisomes: immunocytochemical investigation of peroxisomal membrane proteins in proliferating rat liver peroxisomes and in catalase-negative membrane loops." Journal of Cell Biology 108, n. 6 (1 giugno 1989): 2221–31. http://dx.doi.org/10.1083/jcb.108.6.2221.
Testo completoAbstract (sommario):
Treatment of rats with a new hypocholesterolemic drug BM 15766 induces proliferation of peroxisomes in pericentral regions of the liver lobule with distinct alterations of the peroxisomal membrane (Baumgart, E., K. Stegmeier, F. H. Schmidt, and H. D. Fahimi. 1987. Lab. Invest. 56:554-564). We have used ultrastructural cytochemistry in conjunction with immunoblotting and immunoelectron microscopy to investigate the effects of this drug on peroxisomal membranes. Highly purified peroxisomal fractions were obtained by Metrizamide gradient centrifugation from control and treated rats. Immunoblots prepared from such peroxisomal fractions incubated with antibodies to 22-, 26-, and 70-kD peroxisomal membrane proteins revealed that the treatment with BM 15766 induced only the 70-kD protein. In sections of normal liver embedded in Lowicryl K4M, all three membrane proteins of peroxisomes could be localized by the postembedding technique. The strongest labeling was obtained with the 22-kD antibody followed by the 70-kD and 26-kD antibodies. In treated animals, double-membraned loops with negative catalase reaction in their lumen, resembling smooth endoplasmic reticulum segments as well as myelin-like figures, were noted in the proximity of some peroxisomes. Serial sectioning revealed that the loops seen at some distance from peroxisomes in the cytoplasm were always continuous with the peroxisomal membranes. The double-membraned loops were consistently negative for glucose-6-phosphatase, a marker for endoplasmic reticulum, but were distinctly labeled with antibodies to peroxisomal membrane proteins. Our observations indicate that these membranous structures are part of the peroxisomal membrane system. They could provide a membrane reservoir for the proliferation of peroxisomes and the expansion of this intracellular compartment.
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Suka, Irwan Ginting, Wasinton Simanjuntak e Eniya Listiani Dewi. "Pembuatan Membran Polimer Elektrolit Berbasis Polistiren Akrilonitril (SAN) untuk Aplikasi Direct Methanol Fuel Cell". Jurnal Natur Indonesia 13, n. 1 (21 novembre 2012): 1. http://dx.doi.org/10.31258/jnat.13.1.1-6.
Testo completoAbstract (sommario):
In this study, electrolyte membranes based on polystyrene acrylonitrile (SAN) for Direct Methanol Fuel Cell applicationwere prepared. The preparation was carried out in two steps. The first step was introduction of additives, silicaand zeolite, as reinforcing agent on SAN, to obtain silica-reinforced SAN membrane, specified as SAN-Si, andzeolite-reinforced SAN membranae, specified as SAN-Z. The two reinforced membranes were then subjected tosulphonation using sulphuric acid, and the sulphonated membranes are specified as S-SAN-Si and S-SAN-Z,respectively. The characteristics of the membrane were described in terms of the degree of sulphonation, ionicconductivity, methanol permeability, and percentage of swelling in water and methanol. The results obtaineddemonstrated that additives result in significant reduction of methanol crossover, as reflected by lower values ofmethanol permeability than that obtained for the membrane without additive. It was also found that zeolite functionsrelatively better than silica. For zeolite-modified membrane (S-SAN-Z) the ionic conductivity of 10.05 x 10 -6 S/cmwas achieved. The membrane also marked by methanol permeability of 0.52 x 10 -6, percentage of swelling of 5.12%in water and 2.58% in methanol. Thermal analysis using DSC technique revealed changes in glass transition fromthe original sample, in which the glass transition of the original sample, SAN, (55 0C), sulphonated SAN, S-SAN,(83.360C), silica-modified membrane S-SAN-Si (79.860C), and zeolite-modified membrane S-SAN-Z (79.290C). Additionof additive was also found to influence the surface characteristics of the membranes as revealed by SEM analysis,in which the surface changed from smooth for the original sample into rough for the reinforced samples with bothadditives.
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Mukaromah, Ana Hidayati, Tulus Ariyadi, Inas Hasna Azizah e Mifbakhuddin Mifbakhuddin. "Karakterisasi Membran ZSM-5 yang Disintensis dengan Variasi Jenis dan Ukuran Kasa Penyangga". ALCHEMY Jurnal Penelitian Kimia 16, n. 1 (28 febbraio 2020): 1. http://dx.doi.org/10.20961/alchemy.16.1.25406.1-9.
Testo completoAbstract (sommario):
<p>Telah dilakukan sintesis dan karakterisasi membran ZSM-5 dengan penyangga kasa jenis 304 ukuran 200 dan 400 mesh dan jenis kasa AISI 316 ukuran 180 mesh. Tujuan penelitian ini adalah mensintesis membran ZSM-5 dengan penyangga kasa jenis 304 ukuran 200 dan 400 mesh dan jenis kasa AISI 316 ukuran 180 mesh dan mengkarakterisasi membran ZSM-5 hasil sintesis. Sintesis membran dilakukan dengan cara melapiskan prekursor ZSM-5 (<em>coating)</em> pada penyangga kasa yang telah diberi perlakuan dan dipanaskan pada suhu 90 °C selama 4 hari. Selanjutnya, membran yang dihasilkan dikarakterisasi engan metoda <em>X-ray diffraction</em> (XRD), <em>scanning electron microscope-energy dispersive spectroscopy</em> (SEM-EDS) dan <em>Fourier-transform infrared</em> (FTIR). Hasil citra SEM-EDS menunjukkan bahwa ukuran membran ZSM-5 yang semakin besar, menghasilkan jumlah lubang atau pori semakin banyak dengan luasan pori yang semakin kecil. Pola difraksi XRD menunjukkan bahwa membran yang dihasilkan mempunyai intensitas tertinggi pada 2 8º dan 23º yang merupakan karakteristik dari ZSM-5. Hasil spektra FTIR menunjukkan adanya serapan pada bilangan gelombang 450 cm<sup>-</sup><sup>1</sup>yang merupakan ciri khas membran ZSM-5.</p><p class="Text"><strong>Characterization of ZSM-5 Membranes Synthesized by Variation of Support Types and Sizes.</strong> Synthesis and characterization of ZSM-5 membrane were carried out with 304 type 200 and 400 mesh gauze supports and 180 mesh AISI 316 gauze types. The purpose of this study was to synthesize ZSM-5 membrane with 304 type 200 and 400 mesh gauze support and AISI 316 type 180 mesh size 180 mesh and characterize the synthesized ZSM-5 membrane. Membrane synthesis was carried out by coating the pre-treated gauze support with the ZSM-5 precursor and was heated at 90 °C for 4 days. Furthermore, the resulting membrane was characterized by X-ray diffraction (XRD), scanning electron microscope-energy dispersive spectroscopy (SEM-EDS) dan Fourier-transform infrared (FTIR). The SEM-EDX analysis shows that the increasing of ZSM-5 membrane size allowed pores number to increase with smaller pore surface area. The X-ray Diffraction pattern (XRD) shows that the resulting membrane has the highest intensity at 2 of 8º and 23º as the characteristics of ZSM-5. The FTIR spectra results show absorption at wavenumbers 450 cm<sup>-1</sup> which is a characteristic of ZSM-5 membranes.</p>
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Saha, S. N. "Membrane Separations". Current Research in Agriculture and Farming 3, n. 6 (30 dicembre 2022): 19–33. http://dx.doi.org/10.18782/2582-7146.180.
Testo completoAbstract (sommario):
Membrane technology is widely utilised in industries for separation, concentration, filtering, and extraction operations. Membrane technology carries out various applications by utilising simple and specially designed semi-permeable membranes. It uses little energy and is thus considered a green technology. Ultrafiltration (UF), Microfiltration (MF), Nano-filtration (NF), and Reverse osmosis (RO) are membrane filtration methods that have a major influence on the organoleptic and nutritional qualities of juice. The adoption of a membrane method linked with enzymatic hydrolysis resulted in clarified and concentrated fruit juices with good sensory and nutritional quality. Membrane fouling is a significant problem of membrane-based separation processes. Membrane procedures powered by pressure, such as MF, UF, NF, and RO, allow for the separation of components with a wide variety of particle sizes. Because of this, they have a wide range of uses in the food processing business.
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Hermanto, Dhony, Mudasir Mudasir, Dwi Siswanta, Bambang Kuswandi e Nurul Ismillayli. "The Preparation and Characterization of Alginate–Chitosan Membranes as Solid Support for BTB and Urease Entrapment". Molekul 15, n. 1 (23 marzo 2020): 40. http://dx.doi.org/10.20884/1.jm.2020.15.1.527.
Testo completoAbstract (sommario):
A study of alginate-chitosan membrane synthesize was done. The membrane was prepared by mixing alginate hydrosol and chitosan hydrosol at mass ratio of 1:1 and pH of 5.28 approximately. Then it was applied for matrix immobilization of urease and bromothymol blue (BTB) by entrapment technique. The physical, chemical, thermal properties of alginate–chitosan membrane and their impact on immobilized urease activity were investigated. The polymer products were characterized by Fourier Transform Infrared Spectroscopy (FTIR), X-Ray Diffraction (XRD), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), and Scanning Electron Microscopy (SEM). It’s showed that alginate-chitosan membrane was formed by electrostatic interaction. The obtained membran has better mechanical properties than original alginat and chitosan membranes. The immobilization urease into alginate-chitosan membrane retained the catalytic activity of the enzyme, as confirmed by color change of BTB indicator after membrane was immersed in substrate solution (urea). Therefore, alginate-chitosan membrane has good characteristics as matrix of enzyme immobilization.
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Guiet-Bara, Andree, e Michel Bara. "831 — The human amniotic membrane: One membrane or several membranes?" Bioelectrochemistry and Bioenergetics 15, n. 3 (giugno 1986): 427–29. http://dx.doi.org/10.1016/0302-4598(86)85030-9.
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Wang, Jing, Jennifer B. Ptacek, Karla Kirkegaard e Esther Bullitt. "Double-membraned Liposomes Sculpted by Poliovirus 3AB Protein". Journal of Biological Chemistry 288, n. 38 (1 agosto 2013): 27287–98. http://dx.doi.org/10.1074/jbc.m113.498899.
Testo completoAbstract (sommario):
Infection with many positive-strand RNA viruses dramatically remodels cellular membranes, resulting in the accumulation of double-membraned vesicles that resemble cellular autophagosomes. In this study, a single protein encoded by poliovirus, 3AB, is shown to be sufficient to induce the formation of double-membraned liposomes via the invagination of single-membraned liposomes. Poliovirus 3AB is a 109-amino acid protein with a natively unstructured N-terminal domain. HeLa cells transduced with 3AB protein displayed intracellular membrane disruption; specifically, the formation of cytoplasmic invaginations. The ability of a single viral protein to produce structures of similar topology to cellular autophagosomes should facilitate the understanding of both cellular and viral mechanisms for membrane remodeling.
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Szwast, Maciej, e Teresa Suchecka. "Membranes: Improving batch membrane filtration". Filtration + Separation 50, n. 2 (marzo 2013): 38–41. http://dx.doi.org/10.1016/s0015-1882(13)70080-6.
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Ding, Yi, Yong Yao e Francesca M. Marassi. "Membrane Protein Structure Determinationin Membrana". Accounts of Chemical Research 46, n. 9 (24 giugno 2013): 2182–90. http://dx.doi.org/10.1021/ar400041a.
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Pearce, Graeme. "Introduction to membranes: Membrane selection". Filtration & Separation 44, n. 3 (aprile 2007): 35–37. http://dx.doi.org/10.1016/s0015-1882(07)70083-6.
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Ramírez, P., S. Mafé, J. A. Manzanares e J. Pellicer. "Membrane potential of bipolar membranes". Journal of Electroanalytical Chemistry 404, n. 2 (marzo 1996): 187–93. http://dx.doi.org/10.1016/0022-0728(95)04378-0.
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Drioli, E., V. Calabro e Y. Wu. "Microporous membranes in membrane distillation". Pure and Applied Chemistry 58, n. 12 (1 gennaio 1986): 1657–62. http://dx.doi.org/10.1351/pac198658121657.
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Hwang, Sun-Tak. "Inorganic membranes and membrane reactors". Korean Journal of Chemical Engineering 18, n. 6 (novembre 2001): 775–87. http://dx.doi.org/10.1007/bf02705597.
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Brijder, Robert, Matteo Cavaliere, Agustín Riscos-Núñez, Grzegorz Rozenberg e Dragoş Sburlan. "Membrane Systems with Marked Membranes". Electronic Notes in Theoretical Computer Science 171, n. 2 (luglio 2007): 25–36. http://dx.doi.org/10.1016/j.entcs.2007.05.005.
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Fathanah, Umi, Fachrul Razi, Mirna Rahmah Lubis, Mukramah Yusuf, Yanna Syamsuddin, Hesti Meilina, Syawaliah Muchtar, Suraiya Kamaruzzaman e Aula Khairunnisa. "Modifikasi Membran Polyethersulfone dengan Penambahan Nanopartikel Mg(OH)2 dalam Pelarut Dimethyl Sulfoxide". ALCHEMY Jurnal Penelitian Kimia 18, n. 2 (4 settembre 2022): 165. http://dx.doi.org/10.20961/alchemy.18.2.58248.165-173.
Testo completoAbstract (sommario):
<p>Membran Polyethersulfone (PES) bersifat hidrofobik yang memiliki ketahanan rendah terhadap sifat fouling. Fouling pada membran mengakibatkan penurunan kinerja membrane selama proses operasi. Oleh karena itu, modifikasi membran perlu dilakukan untuk meningkatkan sifat hidrofilik membrane. Pada penelitian ini modifikasi dilakukan dengan penambahan nanopartikel Mg(OH)<sub>2</sub> yang bersifat tidak beracun, murah, dan mudah diperoleh. Penambahan aditif nanopartikel Mg(OH)<sub>2</sub> pada membran PES dilakukan dengan cara pencampuran polimer dengan metode <em>non solvent induced phase separation</em> (NIPS) menggunakan pelarut <em>dimethyl sulfoxide</em> (DMSO). DMSO merupakan pelarut polar aprotik yang dapat melarutkan senyawa organik maupun anorganik dengan baik. DMSO juga merupakan pelarut yang tidak beracun, sehingga lebih aman dan ramah lingkungan. Penelitian ini bertujuan untuk menghasilkan membran PES hidrofilik dengan penambahan nanopartikel Mg(OH)<sub>2</sub> dengan unjuk kerja terbaik. Pengaruh penambahan nanopartikel Mg(OH)<sub>2</sub> dalam sistem membran dievaluasi dengan menganalisis perubahan struktur kimia PES menggunakan ATR-FTIR, perubahan morfologi menggunakan SEM, porositas menggunakan metoda gravimetri, serta pengujian kinerja (permeabilitas dan rejeksi) membran. Hasil penelitian menunjukkan bahwa penambahan nanopartikel Mg(OH)<sub>2</sub>, mengakibatkan perubahan pada struktur atau morfologi membrane PES, yang berpengaruh terhadap peningkatan permeabilitas membran. Penambahan nanopartikel Mg(OH)<sub>2</sub> juga meningkatkan porositas membran dari 12% ‒ 40%. Kehadiran gugus hidroksil (-OH) dalam matriks membran dikonfirmasi dengan uji FTIR. Kinerja membran optimum diperoleh pada nilai permeabilitas air sebesar 56,4 L/m<sup>2</sup>.jam.bar, dengan rejeksi asam humus sebesar 61%.</p><p><strong>Modification of Polyethersulfone Membrane with the Addition of Mg(OH)<sub>2 </sub>Nanoparticles in Dimethyl Sulfoxide Solvent. </strong>Polyethersulfone (PES) membrane has hydrophobic characteristics and low resistance to fouling properties. The fouling on the membrane results in a decrease in the performance of the membrane during the operation process. Therefore, membrane modification needs to be done to increase the hydrophilic properties of the membrane. In this study, modifications were made by adding Mg(OH)<sub>2</sub> nanoparticles which are non-toxic, inexpensive, and easy to obtain. The addition of Mg(OH)<sub>2</sub> nanoparticle additives to PES membranes was carried out by blending polymers with the non-solvent induced phase separation (NIPS) method using dimethyl sulfoxide (DMSO) as solvent. DMSO is an aprotic polar solvent that can dissolve both organic and inorganic compounds well. DMSO is also a non-toxic solvent, making it safer and more environmentally friendly. This study aims to produce a hydrophilic PES membrane with the addition of Mg(OH)<sub>2</sub> nanoparticles with the best performance. The effect of adding Mg(OH)<sub>2</sub> nanoparticles in the membrane system was evaluated by analyzing changes in the chemical structure of PES using ATR-FTIR, morphological changes using SEM, porosity using the gravimetric method, and testing the performance (permeability and rejection) of the membrane. The results showed that the addition of Mg(OH)<sub>2</sub> nanoparticles resulted in changes in the structure or morphology of the PES membrane, which affected the increase in membrane permeability. The addition of Mg(OH)<sub>2</sub> nanoparticles also increased the porosity of the membrane from 12% to 40%. The presence of hydroxyl groups (-OH) in the membrane matrix was confirmed by FTIR analysis. The optimum membrane performance was obtained at the water permeability value of 56.4 L/m<sup>2</sup>.h.bar with 61% rejection of humic acid.</p>
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Winocour, Peter D., Cezary Watala, Dennis W. Perry e Raelene L. Kinlough-Rathbone. "Decreased Platelet Membrane Fluidity Due to Glycation or Acetylation of Membrane Proteins". Thrombosis and Haemostasis 68, n. 05 (1992): 577–82. http://dx.doi.org/10.1055/s-0038-1646320.
Testo completoAbstract (sommario):
SummaryPlatelets from diabetic subjects and animals are hypersensitive to agonists in vitro. Membrane fluidity modulates cell function and previously we observed reduced membrane fluidity in platelets from diabetic patients associated with hypersensitivity to thrombin. We previously reported that decreased fluidity of isolated platelet membranes from diabetic patients is associated with increased glycation of platelet membrane proteins, but not with any change in the cholesterol to phospholipid molar ratio. We have now examined in vitro whether incubation of platelet membranes in a high glucose medium causes sufficient glycation to reduce membrane fluidity. Incubation of platelet membranes from control subjects in a high glucose (16.1 mM) medium for 10 days at 37° C led to an increase in the extent of glycation of membrane proteins and a decrease in membrane fluidity (indicated by an increase in steady state fluorescence polarization); most of the changes occurred within the first 3 days of incubation. Incubation of platelet membranes with 5.4 mM glucose had less effect. In contrast, incubation of platelet membranes with the same concentrations of 1–0-methylglucose did not cause a change in either the extent of glycation of proteins or membrane fluidity. We also determined if acetylation by aspirin or acetyl chloride of the sites available for glycation on platelet membrane proteins leads to a similar reduction in membrane fluidity. Pretreatment of platelet membranes with aspirin or acetyl chloride diminished the extent of glycation that occurred when platelet membranes were subsequently incubated with glucose, but membrane fluidity was reduced even in the absence of glucose; subsequent incubation with glucose caused no further reduction in membrane fluidity. Similar results were obtained when red blood cells were incubated with high concentrations of glucose or methyl glucose either with or without pretreatment with aspirin or acetyl chloride. Further experiments using platelet membranes showed that the reduction in membrane fluidity due to aspirin was independent of its acetylating effect on platelet cyclo-oxygenase. Ingestion of aspirin also caused a reduction in membrane fluidity of platelets. Therefore, glycation of platelet membrane proteins reduces membrane fluidity, but the effect results from occupation of the sites available for glycation and not the presence of glucose moieties per se at these sites. Acetylation of platelet membrane proteins either in vitro or in vivo also reduces membrane fluidity; this effect is not associated with platelet hypersensitivity to thrombin.
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Handayani, Sri, Eniya Listiani Dewi, Widodo Wahyu Purwanto e Roekmijati W. Soemantojo. "Pengaruh aditif terhadap karakteristik membran elektrolit polieter-eter keton tersulfonasi untuk aplikasi sel bahan bakar metanol langsung". Jurnal Teknik Kimia Indonesia 6, n. 1 (2 ottobre 2018): 563. http://dx.doi.org/10.5614/jtki.2007.6.1.4.
Testo completoAbstract (sommario):
The influence of the additive on the characteristics of the sulfonated polyether-ether ketone electrolyte membrane for direct methanol fuel cell applicationsThe weakness of comercial membrane (Nafion-117) for the application of direct methanol fuel cell is highly methanol cross-over. It is decreasing the cell voltage. To minimize the methanol cross-over in a membrane, there are two methods can beproposed: the modification of conventional membrane structure (Nafion-117) and development of novel electrolyte membrane (and modified). PEEK can be used as one of alternatives for direct methanol fuel cell membranes. This PEEK polymer has the stability of chemistry mechanic and thermal. In order to increase ionic conductivity and to decrease methanol permeability. It is necessary to make the modification of sulfonated polyether-ether ketone (sPEEK) with adding higroscopic inorganic additives (SiO2 and H-zeolit). The type of additive which can increase ionic conductivity for sPEEK membrane is SiO2 (3 wt.%) 2 times, and decrease ionic conductivity 1,7 times for H-zeolite. Methanol permeability of membrane sPEEK with silica added increase 5 times and H-zeolite 2 times compared to sPEEK membrane without additive. Although composite membrane have increasing methanol permeability but that values are still lower than Nafion-117. Conclusion, the addition of SiO2 as additives has given best performance 0,09 S/cm ionic conductivity, 10-7 cm2/S methanol permeability dan 17 wt.% water swelling.Keywords: Additive, Direct Methanol Fuel Cell, Polyether-Ether Ketone, SiO2, H-ZeoliteAbstrakKelemahan membran komersial (Nafion-117) untuk aplikasi sel bahan bakar metanol langsung (direct methanol fuel cell) adalah methanol crossover yang tinggi, hal tersebut yang dapat menurunkan kinerja voltase sel secara keseluruhan. Dalam rangka mengurangi methanol crossover melalui membran, ada dua pendekatan yaitu modifikasi struktur membran konvensional (Nafion) atau pengembangan membran polimer elektrolit (dan modifikasi). Salah satu polimer aromatik yang menarik perhatian sebagai membran elektrolit pada aplikasi DMFC adalah polieter-eter keton (PEEK) karena polimer tersebut mempunyai kestabilan kimia, mekanik dan panas. Agar dapat meningkatkan konduktivitas ionik dan menurunkan permeabilitas metanol dilakukan modifikasi pada polieter-eter keton tersulfonasi (sPEEK) yaitu dengan menambahkan aditif anorganik yang bersifat higroskopik (SiO2 dan H-zeolit) Jenis aditif yang dapat meningkatkan konduktivitas ionik untuk membran elektrolit adalah SiO2 (3% berat) yaitu sebesar 2 kali, sedangkan H-zeolit menurunkan konduktivitas ionik sebesar 1,7 kali. Permeabilitas metanol membran sPEEK yang ditambahkan SiO2 naik hingga 5x sedangkan yang ditambahkan H-zeolit hanya 2 kali dari membran sPEEK tanpa aditif. Walaupun membran komposit meningkatkan permeabilitas metanol tetapi nilai tersebut masih dibawah membran Nafion-117. Jadi penambahan aditif yang baik dalam membran berbasis polieter-eter keton tersulfonasi adalah SiO2 yang mempunyai konduktivitas ionik 0,09 S/cm, permeabilitas metanol 10-7 cm2/S dan swelling air 17%.Kata kunci : Aditif, Polieter-Eter Keton, Sci Bahan Bakar Metanol Langsung, SiO,, H-Zeolit
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Yeszhanov, A. B. "HYDROPHOBIZATION OF PET TRACK-ETCHED MEMBRANES FOR DIRECT CONTACT MEMBRANE DISTILLATION OF LIQUID RADIOACTIVE WASTES". Eurasian Physical Technical Journal 17, n. 2 (24 dicembre 2020): 45–54. http://dx.doi.org/10.31489/2020no2/45-54.
Testo completoAbstract (sommario):
This article provides the results of liquid low-level radioactive wastes treatment by direct contact membrane distillation using polyethylene terephthalate hydrophobic track-etched membranes. The hydrophobization of track-etched membranes was carried out by UV-induced graft polymerization of triethoxyvinylsilane with styrene and coating with fluorine-containing silanes. Hydrophobic membranes were investigated by scanning electron microscope, Fourier-transform infrared spectroscopy, contact anglemeasurements, and liquid entry pressure analysis. Prepared membranes were tested in treatment of liquid low-level radioactive wastes by membrane distillation. The influence of pore sizes on water flux and rejection degree was studied. Rejection degree was evaluated by conductometry and atomic emission method. Decontamination factors evaluated by gamma-ray spectroscopy for 60Co, 137Cs, and 241Am are 85.4, 1900 and 5.4 for membranes modified with polystyrene and triethoxyvinylsilanewith pore diameters of 142 nm; 85.0, 1462 and 4 for membranes modified with perfluorododecyltrichlorosilanewith pore diameters of 150 nm respectively.
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Liu, Yan Jun, Chun Ying Lv e Jia Yang. "Studies of Protein Absorption and Fouling Behavior on Amphoteric Charged Polypropylene Microfiltration Membrane". Key Engineering Materials 467-469 (febbraio 2011): 2024–29. http://dx.doi.org/10.4028/www.scientific.net/kem.467-469.2024.
Testo completoAbstract (sommario):
To improve the antifouling property of PP membrane, a series of amphoteric charged membranes was prepared by the introduction of cysteine on polypropylene membrane. The modified membrane presents higher water flux than original membrane due to the improved hydrophilicity. It was proved by zeta potential that modified membrane inherited the amphoteric characteristic from cysteine. The isoelectric point of modified membranes are at pH 7.2 and 6.5 for 7.6% and 16.1% grafted membranes respectively. Due to the amphoteric characteristic of both modified membrane and BSA, electrical repulsion exsists among grafting chains and BSA in acid and alkaline solution. As a result, modified membranes have much lower adsorption amount of BSA than original PP membrane. Moreover, modified membranes show obvious antifouling property to BSA, due to the improved hydrophilicity of membrane and the electrical repulsion between BSA and membrane. Therefore, the amphoteric charged membranes modified by cysteine show great potential to resist protein fouling in a wide range of pH.
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Tan, Yong Zen, Nur Hashimah Alias, Mohd Haiqal Abd Aziz, Juhana Jaafar, Faten Ermala Che Othman e Jia Wei Chew. "Progress on Improved Fouling Resistance-Nanofibrous Membrane for Membrane Distillation: A Mini-Review". Membranes 13, n. 8 (11 agosto 2023): 727. http://dx.doi.org/10.3390/membranes13080727.
Testo completoAbstract (sommario):
Nanofibrous membranes for membrane distillation (MD) have demonstrated promising results in treating various water and wastewater streams. Significant progress has been made in recent decades because of the development of sophisticated membrane materials, such as superhydrophobic, omniphobic and Janus membranes. However, fouling and wetting remain crucial issues for long-term operation. This mini-review summarizes ideas as well as their limitations in understanding the fouling in membrane distillation, comprising organic, inorganic and biofouling. This review also provides progress in developing antifouling nanofibrous membranes for membrane distillation and ongoing modifications on nanofiber membranes for improved membrane distillation performance. Lastly, challenges and future ways to develop antifouling nanofiber membranes for MD application have been systematically elaborated. The present mini-review will interest scientists and engineers searching for the progress in MD development and its solutions to the MD fouling issues.
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Chen, Kaikai, Wei Zhao, Changfa Xiao, Hui Zhu e Qiming Wang. "Membrane Fouling Mechanism of HTR-PVDF and HMR-PVDF Hollow Fiber Membranes in MBR System". Water 14, n. 16 (21 agosto 2022): 2576. http://dx.doi.org/10.3390/w14162576.
Testo completoAbstract (sommario):
Membrane fouling has attracted a lot of attention in the membrane separation field. Herein, we selected the homogeneous-reinforced polyvinylidene fluoride (HMR-PVDF) and heterogeneous-reinforced polyvinylidene fluoride (HTR-PVDF) hollow fiber membranes to investigate the fouling mechanism of membranes in membrane bioreactor (MBR) systems. The filtration models, membrane adsorption experiment, and membrane resistance distribution after a long or short time operation were assessed to compare their antifouling properties in order to verify the optimal membrane. The outer surface, shown by an SEM observation of the HMR-PVDF and HTR-PVDF membranes, was rough and smooth, respectively. Moreover, the HMR-PVDF membranes had a higher adsorption capacity than the HTR-PVDF membranes when an equilibrium state was almost 2.81 times that of the original membrane resistance. A cleaning method (mainly physical and chemical) was utilized to illustrate the operational stability of the membranes. In summary, the HMR-PVDF hollow fiber membrane presented better antifouling properties than the HTR-PVDF membranes, which was conducive to industrial implementation.
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Seshimo, Masahiro, Hiromi Urai, Kazuaki Sasa, Hitoshi Nishino, Yuichiro Yamaguchi, Ryoichi Nishida e Shin-ichi Nakao. "Bench-Scale Membrane Reactor for Methylcyclohexane Dehydrogenation Using Silica Membrane Module". Membranes 11, n. 5 (29 aprile 2021): 326. http://dx.doi.org/10.3390/membranes11050326.
Testo completoAbstract (sommario):
Methylcyclohexane-toluene system is one of the most promising methods for hydrogen transport/storage. The methylcyclohexane dehydrogenation can be exceeded by the equilibrium conversion using membrane reactor. However, the modularization of the membrane reactor and manufacturing longer silica membranes than 100 mm are little developed. Herein, we have developed silica membrane with practical length by a counter-diffusion chemical vapor deposition method, and membrane reactor module bundled multiple silica membranes. The developed 500 mm-length silica membrane had high hydrogen permselective performance (H2 permeance > 1 × 10−6 mol m−2 s−1 Pa−1, H2/SF6 selectivity > 10,000). In addition, we successfully demonstrated effective methylcyclohexane dehydrogenation using a flange-type membrane reactor module, which was installed with 6 silica membranes. The results indicated that conversion of methylcyclohexane was around 85% at 573 K, whereas the equilibrium conversion was 42%.
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Huang, Rui, Hui Pan, Xing Zheng, Chao Fan, Wenyan Si, Dongguan Bao, Shanshan Gao e Jiayu Tian. "Effect of Membrane Pore Size on Membrane Fouling of Corundum Ceramic Membrane in MBR". International Journal of Environmental Research and Public Health 20, n. 5 (4 marzo 2023): 4558. http://dx.doi.org/10.3390/ijerph20054558.
Testo completoAbstract (sommario):
Ceramic membrane has emerged as a promising material to address the membrane fouling issue in membrane bioreactors (MBR). In order to optimize the structural property of ceramic membrane, four corundum ceramic membranes with the mean pore size of 0.50, 0.63, 0.80, and 1.02 μm were prepared, which were designated as C5, C7, C13, and C20, respectively. Long-term MBR experiments showed that the C7 membrane with medium pore size experienced the lowest trans-membrane pressure development rate. Both the decrease and increase of membrane pore size would lead to more severe membrane fouling in the MBR. It was also interesting that with the increase of membrane pore size, the relative proportion of cake layer resistance in total fouling resistance was gradually increased. The content of dissolved organic foulants (i.e., protein, polysaccharide and DOC) on the surface of C7 was quantified as the lowest among the different ceramic membranes. Microbial community analysis also revealed the C7 had a lower relative abundance of membrane fouling associated bacteria in its cake layer. The results clearly demonstrated that ceramic membrane fouling in MBR could be effectively alleviated through optimizing the membrane pore size, which was a key structural factor for preparation of ceramic membrane.
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Herlina, Herlina, Aswin Falahudin, Irfan Gustian, Agus Martono H. Putranto, Morina Adfa e Salprima Yudha S. "Membran Alginat Padina sp. - Polietilen Glikol (AP-PEG): Preparasi, Karakterisasi dan Aplikasinya sebagai Enkapsulan". ALCHEMY Jurnal Penelitian Kimia 17, n. 1 (8 marzo 2021): 63. http://dx.doi.org/10.20961/alchemy.17.1.41713.63-73.
Testo completoAbstract (sommario):
<p>Pengembangan penelitian tentang material berbasiskan sumber daya alam lokal dan dapat diperbaharui terus dikembangkan akhir-akhir ini. Hal tersebut didasari adanya kebutuhan material baru dengan karakteristik yang lebih menguntungkan dan dapat digunakan pada aplikasi yang spesifik. Penelitian ini bertujuan untuk mempelajari preparasi membran alginat-polietilen glikol (AP-PEG) dan aplikasinya sebagai enkapsulan. Alginat yang digunakan adalah hasil ekstraksi dari rumput laut cokelat <em>Padina sp. </em>Dengan metode maserasi jalur asam alginat. Preparasi membrane alginat <em>Padina sp.</em>-polietilen glikol (AP-PEG) dilakukan dengan perbandingan PEG-AP = 1:5; 1:10; 1:15; 0:1 (b/b). Analisis gugus fungsi terhadap seluruh membran yang dihasilkan, menunjukkan bahwa membran AP-PEG yang dihasilkan diprediksi sebagai hasil <em>blending </em>secara fisika karena tidak ada gugus fungsi baru yang terbentuk. Membran dengan perbandingan berat PEG-AP=1:15 memiliki karakteristik terbaik dengan persentase <em>swelling </em>sebesar 1465,5%, <em>stress </em>sebesar 14,588 MPa, <em>strain </em>0,07 dan <em>Modulus Young </em>sebesar 193,13 MPa. Hasil analisis morfologi menunjukkan bahwa banyak rongga ditemukan pada membrane tersebut. Hasil uji disolusi terhadap membrane tersebut menunjukkan bahwa, pada pH 1,2 membran tersebut dapat melepaskan vitamin C sebesar 78,12% selama 60 menit dan tidak mengalami <em>cracking</em>. Di sisi lain, pada pH 7,2 membran tersebut dapat melepaskan vitamin C sebesar 83,54% dan <em>cracking </em>terjadi dalam waktu 12 menit. Hasil penelitian ini menunjukkan bahwa komposit AP-PEG dapat dibuat dari rumput laut coklat dan memiliki kemampuan sebagai enkapsulan. </p><p> </p><strong>Alginate <em>Padina sp.</em></strong>-<strong>Polyethylene Glycol (AP</strong>-<strong>PEG) Membranes: Preparation, Characterization and Their Application as Encapsulant</strong>. The development of research on materials based on local and renewable natural resources has been continuously being developed recently. This is based on the need for new materials with more favorable characteristics and can be used in specific applications. This research aims to study the synthesis of alginate-polyethylene glycol (AP-PEG) membranes and their application as an encapsulant. The alginate was extracted from the brown seaweed <em>Padina sp</em>. by maceration method using alginic acid pathway. Alginate <em>Padina sp.</em>-polyethylene glycol (AP-PEG) alginate membrane was prepared with a ratio of PEG:AP = 1: 5, 1:10, 1:15 and 0:1 (w/w). The functional group analysis showed that the resulting AP-PEG membranes were predicted as a result of physical blending due to no new functional groups are formed. The membrane with a weight ratio of PEG:AP = 1:15 had the best characteristics, with a percentage of swelling of 1465.5%, stress of 14.588 MPa, 0.07 strain, and Young Modulus of 193.13 MPa. Morphological analysis showed that the membrane obtained had many cavities. The dissolution test showed that the AP-PEG membrane was able to release vitamin C of 78.12% for 60 minutes at pH 1.2 and no cracking was observed, while at pH 7.2 the membrane was able to distribute vitamin C by 83.54% and cracking occurs within 12 minutes. The results of this study indicate that AP-PEG composites can be made from brown seaweed and have good encapsulant capabilities.
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Izquierdo-Gil, M. A., J. P. G. Villaluenga, S. Muñoz e V. M. Barragán. "The Correlation between the Water Content and Electrolyte Permeability of Cation-Exchange Membranes". International Journal of Molecular Sciences 21, n. 16 (17 agosto 2020): 5897. http://dx.doi.org/10.3390/ijms21165897.
Testo completoAbstract (sommario):
The salt permeability through three commercial cation-exchange membranes with different morphologies is investigated in aqueous NaCl solutions. Ion-exchange membranes (IEMs) find application in different processes such as electrodialysis, reverse osmosis, diffusion dialysis, membrane electrolysis, membrane fuel cells and ion exchange bioreactors. The aim of this paper is the experimental determination of the electrolyte permeability in the following membranes: MK-40 membrane, Nafion N324 membrane and Nafion 117 membrane. The latter is selected as being a reference membrane. The effect of an increase in the NaCl concentration in the solutions on membranes transport properties is analyzed. With regard to membranes sorption, a decrease in the water content was observed when the external electrolyte concentration is increased. Concerning permeation through the membranes, the salt permeability increased with concentration for the Nafion 117 membrane and remained nearly constant for the other two membranes. A close relation between the degree of liquid sorption by the membranes and the electrolyte permeability was observed.
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Mullineaux, Conrad W., e Lu-Ning Liu. "Membrane Dynamics in Phototrophic Bacteria". Annual Review of Microbiology 74, n. 1 (8 settembre 2020): 633–54. http://dx.doi.org/10.1146/annurev-micro-020518-120134.
Testo completoAbstract (sommario):
Photosynthetic membranes are typically densely packed with proteins, and this is crucial for their function in efficient trapping of light energy. Despite being crowded with protein, the membranes are fluid systems in which proteins and smaller molecules can diffuse. Fluidity is also crucial for photosynthetic function, as it is essential for biogenesis, electron transport, and protein redistribution for functional regulation. All photosynthetic membranes seem to maintain a delicate balance between crowding, order, and fluidity. How does this work in phototrophic bacteria? In this review, we focus on two types of intensively studied bacterial photosynthetic membranes: the chromatophore membranes of purple bacteria and the thylakoid membranes of cyanobacteria. Both systems are distinct from the plasma membrane, and both have a distinctive protein composition that reflects their specialized roles. Chromatophores are formed from plasma membrane invaginations, while thylakoid membranes appear to be an independent intracellular membrane system. We discuss the techniques that can be applied to study the organization and dynamics of these membrane systems, including electron microscopy techniques, atomic force microscopy, and many variants of fluorescence microscopy. We go on to discuss the insights that havebeen acquired from these techniques, and the role of membrane dynamics in the physiology of photosynthetic membranes. Membrane dynamics on multiple timescales are crucial for membrane function, from electron transport on timescales of microseconds to milliseconds to regulation and biogenesis on timescales of minutes to hours. We emphasize the open questions that remain in the field.
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Lim, Huaixun, Kunli Goh, Miao Tian e Rong Wang. "Membrane-based air dehumidification: A comparative review on membrane contactors, separative membranes and adsorptive membranes". Chinese Journal of Chemical Engineering 41 (gennaio 2022): 121–44. http://dx.doi.org/10.1016/j.cjche.2021.12.018.
Testo completo
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Ng, T. C. A., e H. Y. Ng. "Physico-chemical characterisation versus in situ micro-structural characterisation of membrane fouling in membrane bioreactors". Water Science and Technology 63, n. 8 (1 aprile 2011): 1781–87. http://dx.doi.org/10.2166/wst.2011.196.
Testo completoAbstract (sommario):
Fouling characteristics of aerobic submerged membrane bioreactors were analysed under two different membrane materials. Polyethersulfone (PES) membranes were found to foul faster at sub-critical flux than polyolefin (PO) membranes. Physico-chemical characterisation, by means of comparison of extracellular polymeric substances (EPS) and soluble microbial products (SMP) concentrations, as well as the mixed liquor suspended solids (MLSS) concentration were unable to explain the differences in membrane fouling of the contrasting membrane materials. The use of confocal laser scanning microscopy (CLSM) to image organic foulants directly on the membrane surface, coupled with image analyses showed that membrane fouling mechanism shifted from a biofilm initiated process on PO membranes to a bio-organic dominated process on PES membranes under sub-critical flux conditions. These results show that physico-chemical characterisation of an MBR process may not effectively distinguish the effectiveness of different membrane materials, so long as operating conditions are identical, and that characterisation of foulants on the membrane surfaces was necessary to elucidate the differences in membrane fouling.
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Kamaludin, Roziana, Lubna Abdul Majid, Mohd Hafiz Dzarfan Othman, Sumarni Mansur, Siti Hamimah Sheikh Abdul Kadir, Keng Yinn Wong, Watsa Khongnakorn e Mohd Hafiz Puteh. "Polyvinylidene Difluoride (PVDF) Hollow Fiber Membrane Incorporated with Antibacterial and Anti-Fouling by Zinc Oxide for Water and Wastewater Treatment". Membranes 12, n. 2 (19 gennaio 2022): 110. http://dx.doi.org/10.3390/membranes12020110.
Testo completoAbstract (sommario):
The addition of antibacterial material to hollow fiber membranes improves the membrane anti-biofouling characteristics. Antibacterial membranes were fabricated in this study to improve membrane function while also extending membrane lifetime. Neat polyvinylidene difluoride (PVDF) and PVDF hollow fiber membrane with the incorporation of antibacterial agent zinc oxide (ZnO) nanoparticles with various loading (2.5–7.5 wt.%) were fabricated by using dry/wet spinning method. The membrane structure, particle distribution, functional group, hydrophilicity, and pore size of each membrane were all assessed. The result shows that all ZnO/PVDF hollow fiber membranes have the asymmetric structure with even dispersion of ZnO nanoparticles throughout the membranes. The results showed that increased ZnO loadings considerably improved membrane hydrophilicity, and average pore size, in addition to good performance of pure water flux. Antibacterial testing shows that ZnO incorporated in the membrane matrix and membrane surfaces prevents bacteria that cause biofouling from adhering to the membrane. ZnO/PVDF membrane recorded excellent bovine serum albumin (BSA) rejection at 93.4% ± 0.4 with flux recovery rate at 70.9% ± 2.1. These results suggest that antibacterial ZnO/PVDF hollow fiber membranes are promising in relation to reducing biofouling for various water and wastewater treatment.