Letteratura scientifica selezionata sul tema "Clay Absorption and adsorption"
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Articoli di riviste sul tema "Clay Absorption and adsorption"
1
Lu, Haijun, Qian Zhang, Yiqie Dong, Jixiang Li e Xiong Zhang. "The Adsorption Capacity, Pore Structure, and Thermal Behavior of the Modified Clay Containing SSA". Advances in Materials Science and Engineering 2016 (2016): 1–7. http://dx.doi.org/10.1155/2016/9894657.
Testo completoAbstract (sommario):
Sewage sludge ash (SSA) was created by burning municipal sludge. The potential of clay containing 1 or 3 or 5% SSA was assessed for use as a landfill liner-soil material. Batch adsorption, low temperature N2adsorption, and TG-DTA tests were performed to evaluate the adsorption capacity, micropore structure, thermostability, and components of soils under Cr(VI) and Pb(II) chemical solutions. With the increasing amount of SSA in modified clay, the adsorption capacity of Cr(VI) and Pb(II) to the modified clay increases gradually. After absorption, the pore size of modified clay ranges from 2 nm to 8 nm. With the increasing amount of absorption, the pore volume decreases and the specific surface area increases. With the increasing of adsorption concentration of Cr(VI) and Pb(II), the mass loss percentage of modified clay increases to 23.4% and 12.6%, respectively. The modified clay containing SSA may be used as a good barrier material to attenuate contamination of Cr(VI) and Pb(II) in landfills.
2
Novitasari, Sholihah, Sriatun Sriatun e Taslimah Taslimah. "Aluminum Pillared Clay (Al-PILC) for Adsorption of Dyes in Red Fruit Oil". Jurnal Kimia Sains dan Aplikasi 24, n. 1 (8 febbraio 2021): 9–14. http://dx.doi.org/10.14710/jksa.24.1.9-14.
Testo completoAbstract (sommario):
Red fruit oil contains carotene, which is dark orange, so it is not very popular. Therefore, it is necessary to reduce the intensity of the color. Yesterday, in this study, the synthesis and characterization of Al-pillared clay (Al-PILC) from light and heavy clay fractions were carried out. The absorption capacity of red fruit carotene dyes was studied. The research stages included preparation, fractionation, activation, pillarization of clay with aluminum, characterization, and adsorption test for carotene dyes on red fruit. Characterization was carried out using X-ray Diffractometer (XRD) and Gas Sorption Analyzer (GSA). The results showed that basal spacing of natural clay, Al pillared heavy fraction-clay, Al pillared light fraction-clay, activated light fraction were 15.08 Å, 15.27 Å, 16.84 Å, and 16, respectively. 22 Å. The GSA results showed that the surface area and pore volume of the Al pillared light fraction-clay of 0.3 was higher than the heavy fraction. The average pore size of Al pillared light fraction-clay and the heavy fraction was found in the mesoporous range of 30-100 Å, and the adsorption isotherm is type IV. Al-pillared light fraction-clay had higher adsorption ability than a heavy fraction and light fraction before pillaring. When the pillaring agent’s concentration was 0.3 M, Al pillared heavy fraction-has absorption capacity is 58.66%, while Al pillared light fraction-clay is 90.4%.
3
Xu, Hui, Dong Hong Guo e Yao Xu. "Removal of Cu(II) Ions from Aqueous Solution by KH-570 Modified Attapulgite Clay". Advanced Materials Research 320 (agosto 2011): 275–79. http://dx.doi.org/10.4028/www.scientific.net/amr.320.275.
Testo completoAbstract (sommario):
Attapulgite clay (ATP) was modified by Silane coupling agent (KH-570) to creat more efficient sites for Cu(II) adsorption. The natural and KH-570 modified attapulgite clay were characterized by Fourier transform infrared spectrometer (FTIR) and SEM. The effects of various experimental parameters such as the amount of modifier, the quality of KH-570 modified ATP, adsorption time, adsorption temperature on Cu(II) adsorption onto KH-570modified ATP were studied in detail. The results showed that the 30% of modifier (The quality of the modifier mass fraction attapulgite) had the best adsorption capacity. When the dosage of modified attaplgite clay was 0.5g and the absorption time was 240min under 20°C, the adsorption rate of Cu(II) in wastewater approached 97%. Meanwhile, the type of absorption was Langmuir isotherm. Desorption experiments showed that the adsorption mechanism of KH-570 modified ATP to Cu(II) was the chemical adsorption.
4
Wang, Hongyan, Shangwen Zhou, Jiehui Zhang, Ziqi Feng, Pengfei Jiao, Leifu Zhang e Qin Zhang. "Clarifying the Effect of Clay Minerals on Methane Adsorption Capacity of Marine Shales in Sichuan Basin, China". Energies 14, n. 20 (19 ottobre 2021): 6836. http://dx.doi.org/10.3390/en14206836.
Testo completoAbstract (sommario):
The effect of clay minerals on the methane adsorption capacity of shales is a basic issue that needs to be clarified and is of great significance for understanding the adsorption characteristics and mechanisms of shale gas. In this study, a variety of experimental methods, including XRD, LTNA, HPMA experiments, were conducted on 82 marine shale samples from the Wufeng–Longmaxi Formation of 10 evaluation wells in the southern Sichuan Basin of China. The controlling factors of adsorption capacities were determined through a correlation analysis with pore characteristics and mineral composition. In terms of mineral composition, organic matter (OM) is the most key methane adsorbent in marine shale, and clay minerals have little effect on methane adsorption. The ultra-low adsorption capacity of illite and chlorite and the hydrophilicity and water absorption ability of clay minerals are the main reasons for their limited effect on gas adsorption in marine shales. From the perspective of the pore structure, the micropore and mesopore specific surface areas (SSAs) control the methane adsorption capacity of marine shales, which are mainly provided by OM. Clay minerals have no relationship with SSAs, regardless of mesopores or micropores. In the competitive adsorption process of OM and clay minerals, OM has an absolute advantage. Clay minerals become carriers for water absorption, due to their interlayer polarity and water wettability. Based on the analysis of a large number of experimental datasets, this study clarified the key problem of whether clay minerals in marine shales control methane adsorption.
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Yermiyahu, Z., I. Lapides e S. Yariv. "Visible absorption spectroscopy study of the adsorption of Congo Red by montmorillonite". Clay Minerals 38, n. 4 (dicembre 2003): 483–500. http://dx.doi.org/10.1180/0009855033840110.
Testo completoAbstract (sommario):
AbstractThe adsorption of the anionic dye Congo Red (CR) by Na-, Cs-, Mg-, Cu-, Al- and Fe-montmorillonite was investigated by electronic spectroscopy. Spectra of the aqueous suspensions of different clay concentrations and different loadings were recorded. The spectra were curve fitted and were compared to spectra of aqueous solutions of CR at different pH values. Four bands representing anionic varieties and two representing protonated varieties of CR were identified in spectra of CR-treated Na-, Cs-, Mg-, Cu- and Al-montmorillonite. Spectra of CR-treated Femontmorillonite were slightly different, showing three bands representing anionic varieties and four representing protonated CR. The ratio between areas of bands, which represent the protonated varieties, and those representing the anionic varieties were determined showing correlation with the acidity of the metallic cation. The clay in the aqueous suspensions became coloured after the adsorption of CR. The following stainings were obtained, Na- and Mg-clay, red, Cs-clay, violet-red, Cu-clay, reddish-violet, Al-clay, dark violet and Fe-clay, dark blue. It appears that CR can serve as an indicator of the surface acidity of montmorillonite. The effects of aging on the sorption of the dye and on the surface-acidity of the CR-clay complex were investigated.
6
Jasmin Shah, Jasmin Shah, Muhammad Rasul Jan Muhammad Rasul Jan, Mian Muhammad Mian Muhammad e Behisht Ara and Changeez Ahmad Behisht Ara and Changeez Ahmad. "Organo-Clay as Adsorbent for Removal of Fenoxaprop-p-ethyl from Water Samples; A Statistical Approach". Journal of the chemical society of pakistan 43, n. 3 (2021): 278. http://dx.doi.org/10.52568/000575/jcsp/43.03.2021.
Testo completoAbstract (sommario):
In this study, fuller’s earth (FE) modified with sodium dodecylbenzene sulphonic acid was used for adsorptive removal of fenoxaprop-p-ethyl (FPE) herbicide from water samples and statistical validation of the experimental observations was accomplished. All the adsorption experiments were conducted in batch mode. The effect of pH, agitation time, adsorbent dose and initial herbicide concentration on adsorption process was studied. About 98.5% adsorption efficiency was achieved at initial analyte concentration of 1000 mg L-1 at pH 6 within 60 min at adsorbent dose of 0.1 g. The adsorption kinetics were studied and pseudo-second-order kinetic model was found to follow the adsorption kinetics with R2=0.998. The isotherm studies show that the adsorption data fit well to the Freundlich isotherms. In statistical evaluation, the individual as well as the interaction effect of various factors on adsorption was investigated and it was found that concentration, pH and adsorbent dose are the significant factors with p values of 0.0001, 0.004 and 0.006 respectively, while contact time was found statistically insignificant having p value greater than 0.05. The coefficient of determination (R2=0.930) shows that % adsorption is highly dependent on the studied factors and their interactions. Under the optimized set of conditions, high absorption capacity of 200.22 mg g-1 was achieved.
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Jasmin Shah, Jasmin Shah, Muhammad Rasul Jan Muhammad Rasul Jan, Mian Muhammad Mian Muhammad e Behisht Ara and Changeez Ahmad Behisht Ara and Changeez Ahmad. "Organo-Clay as Adsorbent for Removal of Fenoxaprop-p-ethyl from Water Samples; A Statistical Approach". Journal of the chemical society of pakistan 43, n. 3 (2021): 278. http://dx.doi.org/10.52568/000575.
Testo completoAbstract (sommario):
In this study, fuller’s earth (FE) modified with sodium dodecylbenzene sulphonic acid was used for adsorptive removal of fenoxaprop-p-ethyl (FPE) herbicide from water samples and statistical validation of the experimental observations was accomplished. All the adsorption experiments were conducted in batch mode. The effect of pH, agitation time, adsorbent dose and initial herbicide concentration on adsorption process was studied. About 98.5% adsorption efficiency was achieved at initial analyte concentration of 1000 mg L-1 at pH 6 within 60 min at adsorbent dose of 0.1 g. The adsorption kinetics were studied and pseudo-second-order kinetic model was found to follow the adsorption kinetics with R2=0.998. The isotherm studies show that the adsorption data fit well to the Freundlich isotherms. In statistical evaluation, the individual as well as the interaction effect of various factors on adsorption was investigated and it was found that concentration, pH and adsorbent dose are the significant factors with p values of 0.0001, 0.004 and 0.006 respectively, while contact time was found statistically insignificant having p value greater than 0.05. The coefficient of determination (R2=0.930) shows that % adsorption is highly dependent on the studied factors and their interactions. Under the optimized set of conditions, high absorption capacity of 200.22 mg g-1 was achieved.
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Hoving, Alwina L., Melanie A. Münch, Christophe Bruggeman, Dipanjan Banerjee e Thilo Behrends. "Kinetics of selenite interactions with Boom Clay: adsorption–reduction interplay". Geological Society, London, Special Publications 482, n. 1 (2019): 225–39. http://dx.doi.org/10.1144/sp482-2018-60.
Testo completoAbstract (sommario):
AbstractThe speciation of selenium (Se) in clay-rich host rocks is important within the framework of geological disposal of radioactive waste since it affects its migration. Removal of selenite from formation water can be caused by reduction and adsorption. Reduction could potentially be inhibited or delayed by adsorption. Here, the interplay of adsorption and reduction of selenite was investigated in batch experiments with Boom Clay and its separated size fractions. In all experiments, dissolved Se concentrations (Seaq) showed a fast initial decrease that was followed by a slower decline until removal was almost complete. X-ray absorption spectroscopy indicated that adsorption of selenite accounted for the fast removal of Seaq followed by slower selenite reduction. Eventually, almost all solid-bound SeIV became reduced to Se0 in all experiments. The progress of Seaq removal and SeIV reduction to Se0 could be described by a kinetic model involving reversible adsorption on clay minerals and reduction by pyrite. This implies that the reduction of selenite to Se0 is not significantly hindered or delayed by selenite adsorption on clay minerals. Pyrite is probably the most relevant reductant for selenite in Boom Clay, although reduction by FeII structurally bound in clay minerals might provide an additional pathway for selenite reduction in clay rocks.
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Râpă, Maria, Anca Andreea Ţurcanu, Ecaterina Matei, Andra Mihaela Predescu, Mircea Cristian Pantilimon, George Coman e Cristian Predescu. "Adsorption of Copper (II) from Aqueous Solutions with Alginate/Clay Hybrid Materials". Materials 14, n. 23 (25 novembre 2021): 7187. http://dx.doi.org/10.3390/ma14237187.
Testo completoAbstract (sommario):
Massive amounts of industrial and agricultural water around the world are polluted by various types of contaminants that harm the environment and affect human health. Alginic acid is a very versatile green polymer used for heavy metal adsorption due to its availability, biocompatibility, low cost, and non-toxic characteristics. The aim of this paper was to prepare new low-cost hybrid composite beads using sodium alginate with treated montmorillonite and kaolin for the adsorption of copper (Cu) cations. Modified and unmodified clays were investigated by studying their morphology and elemental composition, functional groups, and mean particle size and particle size distribution. The characterization of alginate/clay hybrid composite beads was carried out by evaluating surface morphology (by scanning electron microscopy, SEM), crystallinity (by X-ray diffraction, XRD), and point of zero charge (pHpzc)(Zeta Potential Analyzer). Batch adsorption experiments of alginate/clay hybrid composite beads investigated the effect of metal concentration in the range of 1–4 mg L−1 on Cu(II) removal, adsorption kinetic for maximum 240 min, and Langmuir and Freundlich adsorption isotherms by using atomic absorption spectrometry. The pseudo-second-order kinetic model best fitted the adsorption for alginate/montmorillonite beads (R2 = 0.994), while the diffusion process was predominant for montmorillonite/kaolin beads (R2 = 0.985). The alginate/clay hybrid materials best fitted the Langmuir isotherm model.
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Sasria, Nia, Aprina Dewi Rizki e Gusti Umindya Nur Tajalla. "Removal of Lead Ions (Pb<sup>2+</sup>) Using Acid-Activated Clay from East Kalimantan". Materials Science Forum 1076 (8 dicembre 2022): 91–100. http://dx.doi.org/10.4028/p-es4k1t.
Testo completoAbstract (sommario):
This study aims to determine the optimal conditions of acid-activated clay adsorbent in adsorption of Pb2+ metal ions. Clay was taken around East Kalimantan, Karang Joang. This adsorbent was prepared by mixing clay into a solution of KMnO4, H2SO4 and HCl successively, and stirred for 4 hours at a temperature of 80°C. The morphology and active groups of the adsorbent were analyzed using BET and FTIR. The variables of this study were the mass of the adsorbent 0.1, 0.3 and 0.5 grams and the contact time of 5, 30 and 55 minutes. Adsorption capacity of this adsorbent was analyzed using Atomic Absorption Spectrophotometry (AAS). The results of this study indicate that the optimum mass of adsorbent is 0.1 g, and contact time is 30 minutes. Adsorption capacity of Pb2+ metal ions by acid-activated clay adsorbent at the optimum condition of 0.1 gram was 23,585 mg/g and adsorption energy was 2,338 kJ/mol. Meanwhile, at the optimum condition for 30 minutes, the adsorption capacity was 0.771 mg/L, and the adsorption energy was 2.895 kJ/mol. So that the adsorption process in this study can be known, namely physical adsorption because the adsorption energy value is less than 40 kJ/mol.
Tesi sul tema "Clay Absorption and adsorption"
1
Yiannakakis, Alexandros Emmanuel 1959. "Adsorption/desorption of phenols on the Pima clay loam soil". Thesis, The University of Arizona, 1988. http://hdl.handle.net/10150/276709.
Testo completoAbstract (sommario):
A linear distribution isotherm described the sorption/desorption of four phenols on the Pima clay loam soil. The linear distribution coefficients for 2,4-dichlorophenol, 2-chlorophenol, phenol and 2,4,6-trichlorophenol were 3.61, 2.93, 0.87, and 0.79. Ionization of the phenols affected their relative distribution order. Hydrogen bonding of phenols to exposed mineral sites accounted for the greater measured sorption than was predicted. The effect of solid concentration on the distribution of phenols was tested over a 10-fold soil/solution range. When a log transformation was performed on the data, a highly significant inverse relationship existed between the distribution of phenols and the soil/solution ratio. A 3-fold increase in the dissolved organic carbon in solution was associated with the decrease in the distribution coefficient. A 3-fold increase in the fraction organic carbon in the soil occurred when dry sludge solids were added to the Pima soil. A substantial increase in the dissolved organic carbon in solution was associated with the addition of sludge solids to the soil. (Abstract shortened with permission of author.)
2
Aylmore, Lance Arthur Graham. "Sorption and transport processes in relation to soil structure, water retention, solute mobility and water uptake by plant roots". Title page, table of contents and summary only, 2002. http://web4.library.adelaide.edu.au/theses/09SD/09sda979.pdf.
Testo completoAbstract (sommario):
"April, 2002" Includes bibliographical references and Publications list (leaves 22-30) V. 1. nos.1-50 -- v. 2. nos. 51-105 "Selected research publications submitted to the University of Adelaide for the degree of Doctor of Science."
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Ward, Philip R. "Generation of water repellence in sands, and its amelioration by clay addition /". Adelaide, 1993. http://web4.library.adelaide.edu.au/theses/09PH/09phw262.pdf.
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Ward, Philip R. "Generation of water repellence in sands, and its amelioration by clay addition / Philip R. Ward". Thesis, Adelaide, 1993. http://hdl.handle.net/2440/21659.
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Don-Pedro, Esther A. "The effects of soil properties and clay minerals on the bioremediation of soils contaminated with pentachlorophenol". Akron, OH : University of Akron, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=akron1126632988.
Testo completoAbstract (sommario):
Thesis (M.S.)--University of Akron, Dept. of Geology, 2005."August, 2005." Title from electronic thesis title page (viewed 11/29/2005) Advisor, Annabelle Foss; Committee members, Teresa Cutright, Ira Sasowsky; Department Chair, John Szabo; Dean of the College, Charles B. Monroe; Dean of the Graduate School, George R. Newkome. Includes bibliographical references.
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Varzacacou, Nicolas do Nascimento. "Interação de gasolina, benzeno, tolueno e xilenos com argilominerais esmectíticos da Formação Resende, Bacia de São Paulo". Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/44/44142/tde-08092009-155727/.
Testo completoAbstract (sommario):
Dados da CETESB revelam que a comercialização de derivados do petróleo na Cidade de São Paulo, em especial a gasolina, tem gerado um número significativo de casos de vazamento de combustíveis, causados pela falta de manutenção de equipamentos, deterioração de tanques e tubulações, e falhas operacionais decorrentes do despreparo dos profissionais que atuam nesses estabelecimentos. A área urbana da Cidade de São Paulo está, em grande parte, edificada sobre os depósitos sedimentares de idade cenozóica da Bacia de São Paulo, onde a Formação Resende apresenta distribuição generalizada e compreende mais de 80% do preenchimento sedimentar. Argilominerais esmectíticos predominam na fração fina dos sedimentos da Formação Resende e a possível interação deles com hidrocarbonetos foi o objeto de investigação dessa dissertação. Nesse sentido, o presente trabalho teve por objetivo o estudo laboratorial da interação, por meio de sorção e desorção, de hidrocarbonetos encontrados comumente, como gasolina comercial, benzeno, tolueno e xilenos, com argilominerais esmectíticos da Formação Resende, no contexto da zona vadosa, na Bacia de São Paulo. Para tanto, três amostras argilosas da Formação Resende foram coletadas na zona leste da Cidade de São Paulo, tendo sido efetuada sua caracterização granulométrica, mineralógica (via DRX) e química (análise de CNH). Em testes de inchamento com gasolina e orgânicos puros, nenhuma das amostras apresentou absorção dos compostos. Os testes de adsorção e desorção procuraram caracterizar a interação dos hidrocarbonetos com a rocha total, fração silte e fração argila dos sedimentos, variandose o tempo de exposição (30 minutos a 32 dias) das amostras aos contaminantes. Os resultados obtidos permitiram reconhecer que a adsorção é o mecanismo de sorbância predominante. A variação das concentrações ao longo do tempo evidenciou que a interação amostra/contaminante é dinâmica ao longo do tempo de contato, havendo momentos distintos de sorbância, com variação significativa e bem representada dos teores adsorvidos, e que essas fases ocorrem independentemente da granulometria ou mineralogia das amostras, sendo: os sedimentos argilosos adsorvem, na média, as mesmas ordens de grandeza de cada contaminante, o que é devido a sua homogeneidade granulométrica e mineralógica em pequena escala; dentro da ordem de grandeza de adsorção de cada contaminante, as diferenças composicionais (granulométricas e mineralógicas) entre as amostras de sedimentos argilosos alteram os teores dos compostos em função da proporção de argila na rocha total, de forma que quanto mais contaminante será adsorvido, e do tipo de argilomineral predominante na fração argila, sendo a maior proporção de esmectita um fator favorável.Data from the Environmental Agency of São Paulo State (Company of Environmental Sanitation Technology CETESB) reveal that the commercialization of petroleum products in the city, especially gasoline, has generated a high number of fuel leakages and contaminated areas. The urban area of São Paulo city is underlain by the Cenozoic sedimentary deposits of the São Paulo Basin. In this basin, smectiterich mudstone of the Resende Formation is widely distributed and comprises over 80% of the sedimentary filling. The aim of this study was to investigate the interaction of smectiterich mudstone of the Resende Formation with hydrocarbons in the São Paulo Basin. The sorption and desorption of common hydrocarbons, such as gasoline, benzene, toluene and xylene, by the smectitic clay minerals, in the context of vadose zone, were investigated in laboratory. Three representative subsurface samples of mudstone were collected in the east part of São Paulo city and characterized by granulometry, Xray analysis and CHN determination. Swelling test with gasoline and pure organic compounds does not promote absorption in the three studied samples. Adsorption and desorption tests were employed to characterize the interaction between the hydrocarbons and the wholerock, silt and clayfractions of the mudstone in different time intervals of contact (30 minutes to 32 days). The results revealed the adsorption as the main interaction mechanism. Variations in concentration of contaminants in different time intervals of contact indicated a dynamic interaction between sample and hydrocarbons, existing phases with distinct amounts of organics adsorbed (or retained after desorption). Theses phases are controlled by the time of contact and are independent of samples granulometry and mineralogy, and contaminant type. The three mudstone samples adsorb about the same amount of each contaminant, which is due to their overall granulometric and mineralogic homogeneity. Nevertheless, minor and local changes in sample composition (granulometry and mineralogy) cause a small scale variation in the amounts of each contaminant adsorbed as a result either of clay proportion in the whole-rock and of the predominant clay mineral in the clay fraction.
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De, Oliveira Tiago. "Absorption de produits pharmaceutiques par les organoclays : des matériaux polyvalents pour des applications environnementales". Thesis, Orléans, 2019. http://www.theses.fr/2019ORLE3001.
Testo completoAbstract (sommario):
L’adsorption sur un substrat représente un moyen simple, efficace et peu couteux pour remédier aux polluants inorganiques et organiques. Les minéraux argileux ont montré par le passé des propriétés d’adsorption exceptionnelles pour de nombreux composés organiques. La modification chimique de leur surface via l’intercalation de surfactant, pour la préparation d’organoclays, permet d’améliorer leurs capacités d’adsorption, en particulier vis-à-vis des composés organiques hydrophobes tels que les produits pharmaceutiques (PPs) qui sont de plus en plus fréquemment retrouvés dans les réseaux d’eaux usées ainsi que les eaux de surface de par leurs fortes consommations et excrétions par la population associées à une inefficacité des systèmes épuratoires conventionnels pour éliminer ces composés. Dans ces travaux, l’adsorption de PPs d’actions thérapeutiques différentes et aux propriétés physico-chimiques variées sur une smectite de référence et des organoclays préparés au moyen de différents surfactants (cationiques et nonioniques) a été étudiée avec une attention particulière sur la détermination des mécanismes d’interactions entre PPs et adsorbants selon diverses conditions expérimentales afin (i) d’évaluer la stabilité des matériaux pour une application en contexte épuratoire et (ii) appréhender le rôle des phases minérales dans le devenir des micropolluants organiques dans le milieu naturel. Les données expérimentales obtenues par un jeu de techniques complémentaire révèlent que les organoclays de manière générale et plus particulièrement ceux préparés avec des surfactants nonioniques semblent être les matériaux les plus polyvalents pour l’adsorption des PPs. Les résultats soulignent également l’importance du milieu hydrophobe généré par l’intercalation de surfactants qui offrent de nouveaux sites d’interaction pour l’adsorption des PPs. Ceci permet de statuer de l’efficacité et du caractère prometteur des organoclays quant à leurs capacités de remédiation des effluents en station d’épurationAdsorption represents an easy, simple and low-cost way to remove both organic and inorganic pollutants in water. Clay minerals are well known for their outstanding adsorption properties for numerous products. The chemical modification of its surface through the intercalation of surfactants for the preparation of organoclays considerably improves the adsorption properties, in particular for hydrophobic organic compounds such as pharmaceutical products (PPs) which are more and more commonly found in sewage and surface water. In the present contribution, the adsorption PPs with different therapeutic actions and varied physicochemical properties onto clay mineral and organoclay derivatives prepared with different surfactants (cationic and nonionic) has been studied with a particular understanding of the interactional mechanisms of PP with the adsorbents in order to (i) evaluate the stability of materials for an application in purifying context and (ii) to apprehend the role of the mineral phases in the fate of organic micropollutants in the natural environment. The experimental data obtained by a set of complementary techniques reveal that organoclays prepared with nonionic surfactants show a versatility for numerous PPs while the hydrophobic environment generated by the grafting of surfactants with alkyl-chains particularly enhances the adsorption of the organic compounds. The study confirmed the efficiency and the promising remediation behavior of organoclays for wastewater treatment
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Mitchell, Scott Christian. "An Improved MUSIC Model for Gibbsite". Diss., CLICK HERE for online access, 2005. http://contentdm.lib.byu.edu/ETD/image/etd831.pdf.
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Bardot, Frédérique. "Les minéraux argileux et leur hétérogénéité superficielle : influence de la nature des cations compensateurs superficiels de l'illite sur les mécanismes d'adsorption de gaz". Vandoeuvre-les-Nancy, INPL, 1998. http://docnum.univ-lorraine.fr/public/INPL_T_1998_BARDOT_F.pdf.
Testo completoAbstract (sommario):
Cette étude contribue à la compréhension des mécanismes d'adsorption de gaz à la surface des minéraux argileux. Le solide utilise est un phyllosilicate 2:1, l'illite du puy. Après purification, neufs échantillons ont été préparés en échangeant les cations compensateurs superficiels avec Li+,Na+, K+, Rb+, Cs+, Mg²+, Ca²+, Sr²+ ou Ba²+. Ces échantillons ont fait l'objet d'une caractérisation préalable par analyses chimiques, thermiques et texturales. Les résultats obtenus montrent que les particules élémentaires sont formées de 5 à 6 feuillets, de surface spécifique de l'ordre de 170 m²/g et organisées en agrégats dont la porosité est pratiquement indépendante de la nature du cation. Les propriétés énergétiques superficielles ont été analysées par adsorption d'azote et d'argon haute résolution et microcalorimétrie d'adsorption basse température à 77K. Le facteur de forme des particules élémentaires ne peut être déduit des isothermes d'adsorption d'argon que pour les échantillons monovalents. La modélisation des isothermes par la méthode dis met en évidence le rôle des cations pour l'adsorption d'azote et d'argon. Des mécanismes ont alors été proposés en considérant deux familles de sites primaires sur lesquels s'adsorbent les premières molécules de gaz : sites primaires associés aux cations et sites primaires associés aux cages hexagonales vides du réseau tétraédrique. Le rôle de ces sites pour l'adsorption d'azote et d'argon est alors discuté. Les mécanismes d'interaction avec l'eau ont enfin été étudiés par gravimétrie d'adsorption de vapeur d'eau et microcalorimétrie d'immersion à 303K. Il apparait que le moteur principal de l'adsorption d'eau est l'hydratation des cations superficiels accessibles. Les résultats ont aussi été analysés et comparés en termes de mouillabilité.
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Zangué, Adjia Henriette. "Adsorption des métaux lourds des eaux usées par les argiles alluviales de l'Extrême-Nord Cameroun". Thesis, Université de Lorraine, 2012. http://www.theses.fr/2012LORR0389/document.
Testo completoAbstract (sommario):
Le développement industriel et urbain accroit la pollution des eaux au Cameroun. Il faut donc rechercher des méthodes de dépollution peu onéreuses et de mise en oeuvre facile. L'objectif de ce travail était d'éliminer les métaux lourds (Cu2+, Pb2+, Hg2+, Cr3+) des eaux usées, par adsorption sur de l'argile brute ou traité thermiquement. L'argile alluviale prélevée dans la région de l'Extrême Nord du Cameroun est essentiellement composée de smectite (46%), kaolinite (38%), interstratifiés (10%) et quartz (5%). Les formules structurales sont (Si3,42Al0,58)(Al0,87Fe0,96Mg0,17)O10(OH)2(C+)0,75 , pour la smectite et Si2Al1,95Fe0,05O5(OH)4. pour la kaolinite. Les cations de métaux lourds s'adsorbent très rapidement sur l'argile brute ; la température et le pH de la solution influencent peu leur adsorption. L'affinité de l'argile pour Cu2+, et Pb2+ est très forte mais faible pour Hg2+ et Cr3+. Le mécanisme proposé est l'échange cationique et la complexation de surface pour l'adsorption de Cu2+, Pb2+ et Cr3+ et un mécanisme de spéciation pour l'adsorption de Hg2+. Les boulettes obtenues par traitement thermique de l'argile au dessus de 500°C sont stables en solution et montrent une bonne capacité d'adsorption des métaux lourds. Les boulettes sont moins efficaces que l'argile brute, mais leur utilisation, évitant la séparation solide-liquide, après adsorption est plus facileThe industrial and urban development increases the water pollution in Cameroon. It becomes imperative to develop inexpensive and easy to manage remediation methods. This work aimed at eliminating heavy metals (Cu2+, Pb2+, Hg2+, Cr3+) from water by adsorption on raw or heat treated clay. The alluvial clay sampled in the far North of Cameroon mainly contains smectite (46%), kaolinite (38%), interlayers (10%) and quartz (5%). The structural formulas are : (Si3,42Al0,58)(Al0,87Fe0,96Mg0,17)O10(OH)2(C+)0,75 for the smectite and Si2Al1,95Fe0,05O5(OH)4 for the kaolinite. The heavy metals cations fastly adsorb on raw clay, the temperature and the pH have not much influence on their adsorption. The clay affinity in relation to Cu2+, and Pb2+ is very strong whereas it is low for Hg2+, Cr3+. For the adsorption of Cu2+, Pb2+ and Cr3+ the proposed mechanisms are the cation exchange and the complexation while for the Hg2+, a mechanism of speciation is involved. The pellets obtained by thremic treatment of the clay above 500°C are stable in solution and they have a good capacity for heavy metals adsorption. Performances of the pellets are lower than those of raw clay, however, their use is easier since they do not need solid-liquid separation after adsorption
Libri sul tema "Clay Absorption and adsorption"
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Sengco, Mario Rhuel. The aggregation of clay minerals and marine microalgal cells: Physicochemical theory and implications for controlling harmful algal blooms. Woods Hole, Mass: Woods Hole Oceanographic Institution, 2001.
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D, Harter Robert, a cura di. Adsorption phenomena. New York: Van Nostrand Reinhold Co., 1986.
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3
Zarzycki, Roman. Absorption: Fundamentals & applications. Oxford: Pergamon Press, 1993.
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Adsorption by carbons. Amsterdam: Elsevier, 2008.
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Collision-induced absorption in gases. Cambridge [England]: Cambridge University Press, 1993.
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W, Cole Milton, e Zaremba Eugene 1946-, a cura di. Physical adsorption: Forces and phenomena. Oxford: Clarendon Press, 1997.
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Gas separation by adsorption processes. London: Imperial College Press, 1997.
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Yang, R. T. Gas separation by adsorption processes. Boston: Butterworths, 1987.
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Yang, R. T. Gas separation by adsorption processes. Singapore: World Scientific, 1997.
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Chattopadhyay, P. Absorption & stripping. New Delhi: Asian Books, 2007.
Cerca il testo completoCapitoli di libri sul tema "Clay Absorption and adsorption"
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Boyadjiev, Christo, Maria Doichinova, Boyan Boyadjiev e Petya Popova-Krumova. "Absorption–Adsorption Method". In Modeling of Column Apparatus Processes, 417–35. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-89966-4_16.
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Boyadjiev, Christo, Maria Doichinova, Boyan Boyadjiev e Petya Popova-Krumova. "Absorption-Adsorption Method". In Modeling of Column Apparatus Processes, 283–94. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-28259-6_11.
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Ismadji, Suryadi, Felycia Edi Soetaredjo e Aning Ayucitra. "Modification of Clay Minerals for Adsorption Purpose". In SpringerBriefs in Molecular Science, 39–56. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-16712-1_3.
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Yang, Wansheng, Shuli Liu, Xiaoqiang Zhai, Yin Bi, Zhangyuan Wang e Xudong Zhao. "Solar Desiccant (Absorption/Adsorption) Cooling/Dehumidification Technologies". In Advanced Energy Efficiency Technologies for Solar Heating, Cooling and Power Generation, 211–86. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-17283-1_7.
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Kaplan, Drora. "Absorption and Adsorption of Heavy Metals by Microalgae". In Handbook of Microalgal Culture, 602–11. Oxford, UK: John Wiley & Sons, Ltd, 2013. http://dx.doi.org/10.1002/9781118567166.ch32.
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Bavière, Marc, Eliane Ruaux e Daniel Defives. "Sulfonate Adsorption on Clay — Influence of the Ionic Environment". In Surfactants in Solution, 506. Boston, MA: Springer US, 1991. http://dx.doi.org/10.1007/978-1-4615-3836-3_38.
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Kim, Ungsoo, Brett M. Schulz e William M. Carty. "Adsorption of Poly (Acrylic Acid) on Commercial Ball Clay". In Ceramic Transactions Series, 129–38. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2012. http://dx.doi.org/10.1002/9781118406861.ch13.
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Keizer, P., e M. G. M. Bruggenwert. "Adsorption of Heavy Metals by Clay-Aluminum Hydroxide Complexes". In Interactions at the Soil Colloid — Soil Solution Interface, 177–203. Dordrecht: Springer Netherlands, 1991. http://dx.doi.org/10.1007/978-94-017-1909-4_6.
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Danoy, Alix, Kardelen Durmaz, Margaux Paoletti, Laetitia Vachez, Annick Roul, Jérôme Sohier e Bernard Verrier. "Aqueous Suspensions of Fuller’s Earth Potentiate the Adsorption Capacities of Paraoxon and Improve Skin Decontamination Properties". In Dermal Absorption and Decontamination, 147–67. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-09222-0_9.
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Janssen, R. P. T., M. G. M. Bruggenwert e W. H. Riemsdijk. "Adsorption of Zn By Complexes of Clay/Al-Hydroxide Polymers". In Soil & Environment, 261–62. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-011-2008-1_55.
Testo completoAtti di convegni sul tema "Clay Absorption and adsorption"
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Nakano, M., K. Kawamura, K. Hara e K. Amemiya. "Adsorption Site of Cs+ in Bentonite: Determination by EXAFS". In ASME 2003 9th International Conference on Radioactive Waste Management and Environmental Remediation. ASMEDC, 2003. http://dx.doi.org/10.1115/icem2003-5000.
Testo completoAbstract (sommario):
This study elucidated the location where Cs atoms resided at the solid–water interface in smectite hydrates that composed bentonite using EXAFS spectroscopy. Samples were prepared by adding 4ml of a 0.1M CsCl solution to 2g dry weight of suspended KunipiaF bentonite at pH 3.9, 7.1, and 9.8. The Cs K-edge absorption was measured in transmission mode at a synchrotron, Spring-8, Japan, using a Si(311) monochromator at room temperature for the wet paste and air-dried compacted samples. Data were analyzed with the program TECHXAS. The structural parameters were determined by a two-oxygen-shell fit using the ab initio program FEFF6 and ATOMS code. EXAFS analyses have suggested that for air-dried samples the first shell consisted of about 5O at a distance of 3.19–3.20 Å, and the second shell consisted of about 7O at a distance of 3.59–3.60 Å. For the wet paste, the first shell was observed at a distance of 3.15–3.16 Å with the coordination number of about 7O. The second shell consisted of about 6O at a distance of 3.59–3.60 Å. Debye-waller factors of the first oxygen shells were 0.021 and 0.04 Å2 for the air-dried and wet paste samples, respectively. For the second oxygen shells they were 0.039 and 0.052 Å2, respectively. Based on coordination numbers and Debye-waller factors, it concluded that the adsorption sites of Cs+ on smectite hydrates were positioned near the edge of the oxygen hexagonal cavity of the siloxane sheets on basal surface, and appeared between two aluminol sheets at fractured sections, assuming that the first shells were formed by oxygen of inter-layer water, and that the second shells consisted of oxygen forming clay minerals. Furthermore, in the wet paste Cs ions were considered to form incomplete inner-sphere-like complexes and to roam freely in inter-layer water in smectite.
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Colon, Yleana M., Liliana F. Alzate, Carmen M. Ramos, Alberto Santana, Samuel P. Hernandez-Rivera, Miguel E. Castro, Miguel Munoz e Nairmen Mina. "Adsorption of RDX on clay". In Defense and Security, a cura di Russell S. Harmon, J. Thomas Broach e John H. Holloway, Jr. SPIE, 2004. http://dx.doi.org/10.1117/12.541703.
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Utubira, Yeslia, Fransiskus Robertho Lesbatta, Julita Beatrix Manuhutu e Victor Kayadoe. "Adsorption of tartrazine dye using Al2O3-pillared clay". In INTERNATIONAL CONFERENCE ON ENERGY AND ENVIRONMENT (ICEE 2021). AIP Publishing, 2021. http://dx.doi.org/10.1063/5.0059548.
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Rodriguez, Fernancelys, Maria Llamedo, Hadi Belhaj e Ahmed Belhaj. "Challenges Associated with the Acid Gases Production and Capture in Hydrocarbon Reservoirs: A Critical Review of the Venezuelan Cases". In SPE Thermal Well Integrity and Production Symposium. SPE, 2022. http://dx.doi.org/10.2118/212146-ms.
Testo completoAbstract (sommario):
Abstract Acid gases production, such as hydrogen sulfide and carbon dioxide, from heavy oil reservoirs in Venezuela is generally associated with the application of thermal enhanced oil recovery methods. These undesired gases, especially H2S, can be removed by injecting chemical additives that promote chemical reactions with oxidative or nonoxidative mechanisms in the producing system to generate fewer toxic byproducts. According to the literature, H2S scavengers evaluated in the oil industry are amines, alkaline sodium nitrite, hydrogen peroxide, triazine, among others. To mitigate both H2S and CO2 from a reservoir, some novel proposals are under study to offer alternatives to control them from the reservoir and reduce their production in surface. This article presents a review of the key parameters that play a role in the generation of acid gases, mainly H2S and CO2, in Venezuelan oil reservoirs. The operational field data, the main reactions and mechanisms involved in the process (e.g., aquathermolysis, hydro pyrolysis), and the type of byproducts generated will be reviewed. The results and knowledge gained will assist in identifying the main insights of the process, associating them with other international field cases published in the literature, and establishing perspectives for the evaluation of the most convenient techniques from health, safety, technical and economic points of view. Lab and field results have shown that the application of thermal EOR methods in reservoirs of the main Venezuelan basins promote the generation of acid gases due to physicochemical transformations of sulfur, and/or fluid-rock interactions. Sulfur content in Venezuelan viscous oil reservoirs, together with rock mineralogy (clay type) has a significant impact on H2S production. Reported lab results also indicated that H2S scavengers reduce the amount of sulfur, and the presence of CO2 also affects the H2S removal mechanisms, depending on which type of scavenger is selected (e.g., amines, triazine, etc.). Solubilization, hydrolysis, adsorption, absorption, and complex sequestrant reactions (oxidation, neutralization, regeneration, and precipitations) are the main mechanisms involved in the removal of H2S. The literature reported that the application of triazine liquid scavengers is found to generate monomeric dithiazine byproducts (amorphous polymeric dithiazine) which might cause formation damage or inflict flow assurance issues upstream and downstream. This work presents a state of the art review on H2S generation mechanisms and new technologies for the mitigation of acid gases in Venezuelan reservoirs. It also provides perspectives for the application of the most convenient technologies for the reduction of greenhouse gas emissions (mostly CO2), which is critical to producing hydrocarbons with low environmental impact.
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Rivera, Rosángela, Julissa Pabón, Omarie Pérez, Miguel A. Muñoz e Nairmen Mina. "Adsorption coefficients for TNT on soil and clay minerals". In Defense and Security Symposium, a cura di Russell S. Harmon, J. Thomas Broach e John H. Holloway, Jr. SPIE, 2007. http://dx.doi.org/10.1117/12.721178.
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Galkin, V., e V. Seredin. "Absorption properties of pressure activated bentonite clay". In I INTERNATIONAL CONFERENCE ASE-I - 2021: APPLIED SCIENCE AND ENGINEERING: ASE-I - 2021. AIP Publishing, 2021. http://dx.doi.org/10.1063/5.0075378.
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Ramos, Carmen M., Liliana F. Alzate, Yleana M. Colon, Samuel P. Hernandez e Nairmen Mina. "Computational modeling of the adsorption of 2,4-DNT on clay". In Defense and Security, a cura di Russell S. Harmon, J. Thomas Broach e John H. Holloway, Jr. SPIE, 2005. http://dx.doi.org/10.1117/12.602755.
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"Surfactant Impregnated Bentonite Clay for the Adsorption of Anionic Dyes". In 7th International Conference on Latest Trends in Engineering and Technology. International Institute of Engineers, 2015. http://dx.doi.org/10.15242/iie.e1115023.
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Agrawal, Devesh Kumar, Radhika Suresh, Qusai Darugar e Valery Khabashesku. "Nanoparticles Treatment for Reducing Surfactant Adsorption in Clay Containing Reservoirs". In Offshore Technology Conference Brasil. Offshore Technology Conference, 2019. http://dx.doi.org/10.4043/29931-ms.
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Cheraghian, G., S. Khalili Nezhad e M. Kamari. "Polymer Adsorption on Reservoir Rocks - The Role of Nanoparticles Clay". In 76th EAGE Conference and Exhibition 2014. Netherlands: EAGE Publications BV, 2014. http://dx.doi.org/10.3997/2214-4609.20141686.
Testo completoRapporti di organizzazioni sul tema "Clay Absorption and adsorption"
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Rogers, V., K. Nielson e G. Merrell. Radon generation, adsorption, absorption, and transport in porous media. Office of Scientific and Technical Information (OSTI), maggio 1989. http://dx.doi.org/10.2172/6004618.
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Litaor, Iggy, James Ippolito, Iris Zohar e Michael Massey. Phosphorus capture recycling and utilization for sustainable agriculture using Al/organic composite water treatment residuals. United States Department of Agriculture, gennaio 2015. http://dx.doi.org/10.32747/2015.7600037.bard.
Testo completoAbstract (sommario):
Objectives: 1) develop a thorough understanding of the sorption mechanisms of Pi and Po onto the Al/O- WTR; 2) determine the breakthrough range of the composite Al/O-WTR during P capturing from agro- wastewaters; and 3) critically evaluate the performance of the composite Al/O-WTR as a fertilizer using selected plants grown in lysimeters and test-field studies. Instead of lysimeters we used pots (Israel) and one- liter cone-tainers (USA). We conducted one field study but in spite of major pretreatments the soils still exhibited high enough P from previous experiments so no differences between control and P additions were noticeable. Due to time constrains the field study was discontinued. Background: Phosphorous, a non-renewable resource, has been applied extensively in fields to increase crop yield, yet consequently has increased the potential of waterway eutrophication. Our proposal impetus is the need to develop an innovative method of P capturing, recycling and reuse that will sustain agricultural productivity while concurrently reducing the level of P discharge from and to agricultural settings. Major Conclusions & Achievements: An innovative approach was developed for P removal from soil leachate, dairy wastewater (Israel), and swine effluents (USA) using Al-based water treatment residuals (Al- WTR) to create an organic-Al-WTR composite (Al/O-WTR), potentially capable of serving as a P fertilizer source. The Al-WTR removed 95% inorganic-P, 80% to 99.9% organic P, and over 60% dissolved organic carbon from the agro-industrial waste streams. Organic C accumulation on particles surfaces possibly enhanced weak P bonding and facilitated P desorption. Analysis by scanning electron microscope (SEM- EDS), indicated that P was sparsely sorbed on both calcic and Al (hydr)oxide surfaces. Sorption of P onto WW-Al/O-WTR was reversible due to weak Ca-P and Al-P bonds induced by the slight alkaline nature and in the presence of organic moieties. Synchrotron-based microfocused X-ray fluorescence (micro-XRF) spectrometry, bulk P K-edge X-ray absorption near edge structure spectroscopy (XANES), and P K-edge micro-XANES spectroscopy indicated that adsorption was the primary P retention mechanism in the Al- WTR materials. However, distinct apatite- or octocalciumphosphatelike P grains were also observed. Synchrotron micro-XRF mapping further suggested that exposure of the aggregate exteriors to wastewater caused P to diffuse into the porous Al-WTR aggregates. Organic P species were not explicitly identified via P K-edge XANES despite high organic matter content, suggesting that organic P may have been predominantly associated with mineral surfaces. In screen houses experiments (Israel) we showed that the highest additions of Al/O-WTR (5 and 7 g kg⁻¹) produced the highest lettuce (Lactuca sativa L. var. longifolial) yield. Lettuce yield and P concentration were similar across treatments, indicating that Al/O- WTR can provide sufficient P to perform similarly to common fertilizers. A greenhouse study (USA) was utilized to compare increasing rates of swine wastewater derived Al/O-WTR and inorganic P fertilizer (both applied at 33.6, 67.3, and 134.5 kg P₂O₅ ha⁻¹) to supply plant-available P to spring wheat (TriticumaestivumL.) in either sandy loam or sandy clay loam soil. Spring wheat straw and grain P uptake were comparable across all treatments in the sandy loam, while Al/O-WTR application to the sandy clay loam reduced straw and grain P uptake. The Al/O-WTR did not affect soil organic P concentrations, but did increase phosphatase activity in both soils; this suggests that Al/O-WTR application stimulated microorganisms and enhance the extent to which microbial communities can mineralize Al/O-WTR-bound organic P. Implications: Overall, results suggest that creating a new P fertilizer from Al-WTR and agro-industrial waste sources may be a feasible alternative to mining inorganic P fertilizer sources, while protecting the environment from unnecessary waste disposal.
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Croft, David T., e David K. Friday. Predicting Absorption Equilibria of Mixtures: Comparison of Potential Theory and Ideal Adsorption Solution Theory. Fort Belvoir, VA: Defense Technical Information Center, ottobre 1999. http://dx.doi.org/10.21236/ada370837.
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Ward, Donald K., Xiaowang Zhou, Richard A. Karnesky, Robert Kolasinski, Michael E. Foster, Konrad Thurmer, Paul Chao et al. Understanding H isotope adsorption and absorption of Al-alloys using modeling and experiments (LDRD: #165724). Office of Scientific and Technical Information (OSTI), settembre 2015. http://dx.doi.org/10.2172/1222665.
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Lahav, Ori, Albert Heber e David Broday. Elimination of emissions of ammonia and hydrogen sulfide from confined animal and feeding operations (CAFO) using an adsorption/liquid-redox process with biological regeneration. United States Department of Agriculture, marzo 2008. http://dx.doi.org/10.32747/2008.7695589.bard.
Testo completoAbstract (sommario):
The project was originally aimed at investigating and developing new efficient methods for cost effective removal of ammonia (NH₃) and hydrogen sulfide (H₂S) from Concentrated Animal Feeding Operations (CAFO), in particular broiler and laying houses (NH₃) and hog houses (H₂S). In both cases, the principal idea was to design and operate a dedicated air collection system that would be used for the treatment of the gases, and that would work independently from the general ventilation system. The advantages envisaged: (1) if collected at a point close to the source of generation, pollutants would arrive at the treatment system at higher concentrations; (2) the air in the vicinity of the animals would be cleaner, a fact that would promote animal growth rates; and (3) collection efficiency would be improved and adverse environmental impact reduced. For practical reasons, the project was divided in two: one effort concentrated on NH₃₍g₎ removal from chicken houses and another on H₂S₍g₎ removal from hog houses. NH₃₍g₎ removal: a novel approach was developed to reduce ammonia emissions from CAFOs in general, and poultry houses in particular. Air sucked by the dedicated air capturing system from close to the litter was shown to have NH₃₍g₎ concentrations an order of magnitude higher than at the vents of the ventilation system. The NH₃₍g₎ rich waste air was conveyed to an acidic (0<pH<~5) bubble column reactor where NH₃ was converted to NH₄⁺. The reactor operated in batch mode, starting at pH 0 and was switched to a new acidic absorption solution just before NH₃₍g₎ breakthrough occurred, at pH ~5. Experiments with a wide range of NH₃₍g₎ concentrations showed that the absorption efficiency was practically 100% throughout the process as long as the face velocity was below 4 cm/s. The potential advantages of the method include high absorption efficiency, lower NH₃₍g₎ concentrations in the vicinity of the birds, generation of a valuable product and the separation between the ventilation and ammonia treatment systems. A small scale pilot operation conducted for 5 weeks in a broiler house showed the approach to be technically feasible. H₂S₍g₎ removal: The main goal of this part was to develop a specific treatment process for minimizing H₂S₍g₎ emissions from hog houses. The proposed process consists of three units: In the 1ˢᵗ H₂S₍g₎ is absorbed into an acidic (pH<2) ferric iron solution and oxidized by Fe(III) to S⁰ in a bubble column reactor. In parallel, Fe(III) is reduced to Fe(II). In the 2ⁿᵈ unit Fe(II) is bio-oxidized back to Fe(III) by Acidithiobacillus ferrooxidans (AF).In the 3ʳᵈ unit S⁰ is separated from solution in a gravity settler. The work focused on three sub-processes: the kinetics of H₂S absorption into a ferric solution at low pH, the kinetics of Fe²⁺ oxidation by AF and the factors that affect ferric iron precipitation (a main obstacle for a continuous operation of the process) under the operational conditions. H₂S removal efficiency was found higher at a higher Fe(III) concentration and also higher for higher H₂S₍g₎ concentrations and lower flow rates of the treated air. The rate limiting step of the H₂S reactive absorption was found to be the chemical reaction rather than the transition from gas to liquid phase. H₂S₍g₎ removal efficiency of >95% was recorded with Fe(III) concentration of 9 g/L using typical AFO air compositions. The 2ⁿᵈ part of the work focused on kinetics of Fe(II) oxidation by AF. A new lab technique was developed for determining the kinetic equation and kinetic parameters (KS, Kₚ and mₘₐₓ) for the bacteria. The 3ʳᵈ part focused on iron oxide precipitation under the operational conditions. It was found that at lower pH (1.5) jarosite accumulation is slower and that the performance of the AF at this pH was sufficient for successive operation of the proposed process at the H₂S fluxes predicted from AFOs. A laboratory-scale test was carried out at Purdue University on the use of the integrated system for simultaneous hydrogen sulfide removal from a H₂S bubble column filled with ferric sulfate solution and biological regeneration of ferric ions in a packed column immobilized with enriched AFbacteria. Results demonstrated the technical feasibility of the integrated system for H₂S removal and simultaneous biological regeneration of Fe(III) for potential continuous treatment of H₂S released from CAFO. NH₃ and H₂S gradient measurements at egg layer and swine barns were conducted in winter and summer at Purdue. Results showed high potential to concentrate NH₃ and H₂S in hog buildings, and NH₃ in layer houses. H₂S emissions from layer houses were too low for a significant gradient. An NH₃ capturing system was designed and tested in a 100-chicken broiler room. Five bell-type collecting devices were installed over the litter to collect NH₃ emissions. While the air extraction system moved only 10% of the total room ventilation airflow rate, the fraction of total ammonia removed was 18%, because of the higher concentration air taken from near the litter. The system demonstrated the potential to reduce emissions from broiler facilities and to concentrate the NH₃ effluent for use in an emission control system. In summary, the project laid a solid foundation for the implementation of both processes, and also resulted in a significant scientific contribution related to AF kinetic studies and ferrous analytical measurements.
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Gerstl, Zev, Thomas L. Potter, David Bosch, Timothy Strickland, Clint Truman, Theodore Webster, Shmuel Assouline, Baruch Rubin, Shlomo Nir e Yael Mishael. Novel Herbicide Formulations for Conservation-Tillage. United States Department of Agriculture, giugno 2009. http://dx.doi.org/10.32747/2009.7591736.bard.
Testo completoAbstract (sommario):
The overall objective of this study was to develop, optimize and evaluate novel formulations, which reduce herbicide leaching and enhance agronomic efficacy. Numerous studies have demonstrated that CsT promotes environmental quality and enhances sustainable crop production, yet continued use of CsT-practices appears threatened unless cost effective alternative weed control practices can be found. The problem is pressing in the southern portion of the Atlantic Coastal Plain region of the eastern USA where cotton and peanut are produced extensively. This research addressed needs of the region’s farmers for more effective weed control practices for CsT systems. HUJI: CRFs for sulfentrazone and metolachlor were developed and tested based on their solubilizion in cationic micelles and adsorption of the mixed micelles on montmorillonite. A better understanding of solubilizing anionic and nonionic organic molecules in cationic micelles was reached. Both CRFs demonstrated controlled release compared to the commercial formulations. A bioassay in soil columns determined that the new sulfentrazone and metolachlor CRFs significantly improve weed control and reduced leaching (for the latter) in comparison with the commercial formulations. ARO: Two types of CRFs were developed: polymer-clay beads and powdered formulations. Sand filter experiments were conducted to determine the release of the herbicide from the CRFs. The concentration of metolachlor in the initial fractions of the effluent from the commercial formulation reached rather high values, whereas from the alginate-clay formulations and some of the powdered formulations, metolachlor concentrations were low and fairly constant. The movement of metolachlor through a sandy soil from commercial and alginate-clay formulations showed that the CRFs developed significantly reduced the leaching of metolachlor in comparison to the commercial formulation. Mini-flume and simulated rainfall studies indicated that all the CRFs tested increased runoff losses and decreased the amount of metolachlor found in the leachate. ARS: Field and laboratory investigations were conducted on the environmental fate and weed control efficacy of a commercially available, and two CRFs (organo-clay and alginate-encapsulated) of the soil-residual herbicide metolachlor. The environmental fate characteristics and weed control efficacy of these products were compared in rainfall simulations, soil dissipations, greenhouse efficacy trials, and a leaching study. Comparisons were made on the basis of tillage, CsT, and conventional, i.e no surface crop residue at planting (CT). Strip-tillage (ST), a commonly used form of CsT, was practiced. The organo-clay and commercial metolachlor formulations behaved similarly in terms of wash off, runoff, soil dissipation and weed control efficacy. No advantage of the organo-clay over the commercial metolachlor was observed. Alginate encapsulated metolachlor was more promising. The dissipation rate for metolachlor when applied in the alginate formulation was 10 times slower than when the commercial product was used inferring that its use may enhance weed management in cotton and peanut fields in the region. In addition, comparison of alginate and commercial formulations showed that ST can effectively reduce the runoff threat that is commonly associated with granular herbicide application. Studies also showed that use of the alginate CRF has the potential to reduce metolachlor leaching. Overall study findings have indicated that use of granular herbicide formulations may have substantial benefit for ST-system weed management for cotton and peanut production under Atlantic Coastal Plain conditions in the southeastern USA. Commercial development and evaluation at the farm scale appears warranted. Products will likely enhance and maintain CsT use in this and other regions by improving weed control options.
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Shenker, Moshe, Paul R. Bloom, Abraham Shaviv, Adina Paytan, Barbara J. Cade-Menun, Yona Chen e Jorge Tarchitzky. Fate of Phosphorus Originated from Treated Wastewater and Biosolids in Soils: Speciation, Transport, and Accumulation. United States Department of Agriculture, giugno 2011. http://dx.doi.org/10.32747/2011.7697103.bard.
Testo completoAbstract (sommario):
Beneficial use of reclaimed wastewater (RW) and biosolids (BS) in soils is accompanied by large input of sewage-originated P. Prolonged application may result in P accumulation up to levelsBeneficial use of reclaimed wastewater (RW) and biosolids (BS) in soils is accompanied by large input of sewage-originated P. Prolonged application may result in P accumulation up to levels that impair plant nutrition, increase P loss, and promote eutrophication in downstream waters. This study aims to shed light on the RW- and BS-P forms in soils and to follow the processes that determine P reactivity, solubility, availability, and loss in RW and BS treated soils. The Technion group used sequential P extraction combined with measuring stable oxygen isotopic composition in phosphate (δ18OP) and with 31P-NMR studies to probe P speciation and transformations in soils irrigated with RW or fresh water (FW). The application of the δ18OP method to probe inorganic P (Pi) speciation and transformations in soils was developed through collaboration between the Technion and the UCSC groups. The method was used to trace Pi in water-, NaHCO3-, NaOH-, and HCl- P fractions in a calcareous clay soil (Acre, Israel) irrigated with RW or FW. The δ18OP signature changes during a month of incubation indicated biogeochemical processes. The water soluble Pi (WSPi) was affected by enzymatic activity yielding isotopic equilibrium with the water molecules in the soil solution. Further it interacted rapidly with the NaHCO3-Pi. The more stable Pi pools also exhibited isotopic alterations in the first two weeks after P application, likely related to microbial activity. Isotopic depletion which could result from organic P (PO) mineralization was followed by enrichment which may result from biologic discrimination in the uptake. Similar transformations were observed in both soils although transformations related to biological activity were more pronounced in the soil treated with RW. Specific P compounds were identified by the Technion group, using solution-state 31P-NMR in wastewater and in soil P extracts from Acre soils irrigated by RW and FW. Few identified PO compounds (e.g., D-glucose-6-phosphate) indicated coupled transformations of P and C in the wastewater. The RW soil retained higher P content, mainly in the labile fractions, but lower labile PO, than the FW soil; this and the fact that P species in the various soil extracts of the RW soil appear independent of P species in the RW are attributed to enhanced biological activity and P recycling in the RW soil. Consistent with that, both soils retained very similar P species in the soil pools. The HUJ group tested P stabilization to maximize the environmental safe application rates and the agronomic beneficial use of BS. Sequential P extraction indicated that the most reactive BS-P forms: WSP, membrane-P, and NaHCO3-P, were effectively stabilized by ferrous sulfate (FeSul), calcium oxide (CaO), or aluminum sulfate (alum). After applying the stabilized BS, or fresh BS (FBS), FBS compost (BSC), or P fertilizer (KH2PO4) to an alluvial soil, P availability was probed during 100 days of incubation. A plant-based bioassay indicated that P availability followed the order KH2PO4 >> alum-BS > BSC ≥ FBS > CaO-BS >> FeSul-BS. The WSPi concentration in soil increased following FBS or BSC application, and P mineralization further increased it during incubation. In contrast, the chemically stabilized BS reduced WSPi concentrations relative to the untreated soil. It was concluded that the chemically stabilized BS effectively controlled WSPi in the soil while still supplying P to support plant growth. Using the sequential extraction procedure the persistence of P availability in BS treated soils was shown to be of a long-term nature. 15 years after the last BS application to MN soils that were annually amended for 20 years by heavy rates of BS, about 25% of the added BS-P was found in the labile fractions. The UMN group further probed soil-P speciation in these soils by bulk and micro X-ray absorption near edge structure (XANES). This newly developed method was shown to be a powerful tool for P speciation in soils. In a control soil (no BS added), 54% of the total P was PO and it was mostly identified as phytic acid; 15% was identified as brushite and 26% as strengite. A corn crop BS amended soil included mostly P-Fe-peat complex, variscite and Al-P-peat complex but no Ca-P while in a BS-grass soil octacalcium phosphate was identified and o-phosphorylethanolamine or phytic acid was shown to dominate the PO fraction that impair plant nutrition, increase P loss, and promote eutrophication in downstream waters. This study aims to shed light on the RW- and BS-P forms in soils and to follow the processes that determine P reactivity, solubility, availability, and loss in RW and BS treated soils. The Technion group used sequential P extraction combined with measuring stable oxygen isotopic composition in phosphate (δ18OP) and with 31P-NMR studies to probe P speciation and transformations in soils irrigated with RW or fresh water (FW). The application of the δ18OP method to probe inorganic P (Pi) speciation and transformations in soils was developed through collaboration between the Technion and the UCSC groups. The method was used to trace Pi in water-, NaHCO3-, NaOH-, and HCl- P fractions in a calcareous clay soil (Acre, Israel) irrigated with RW or FW. The δ18OP signature changes during a month of incubation indicated biogeochemical processes. The water soluble Pi (WSPi) was affected by enzymatic activity yielding isotopic equilibrium with the water molecules in the soil solution. Further it interacted rapidly with the NaHCO3-Pi. The more stable Pi pools also exhibited isotopic alterations in the first two weeks after P application, likely related to microbial activity. Isotopic depletion which could result from organic P (PO) mineralization was followed by enrichment which may result from biologic discrimination in the uptake. Similar transformations were observed in both soils although transformations related to biological activity were more pronounced in the soil treated with RW. Specific P compounds were identified by the Technion group, using solution-state 31P-NMR in wastewater and in soil P extracts from Acre soils irrigated by RW and FW. Few identified PO compounds (e.g., D-glucose-6-phosphate) indicated coupled transformations of P and C in the wastewater. The RW soil retained higher P content, mainly in the labile fractions, but lower labile PO, than the FW soil; this and the fact that P species in the various soil extracts of the RW soil appear independent of P species in the RW are attributed to enhanced biological activity and P recycling in the RW soil. Consistent with that, both soils retained very similar P species in the soil pools. The HUJ group tested P stabilization to maximize the environmental safe application rates and the agronomic beneficial use of BS. Sequential P extraction indicated that the most reactive BS-P forms: WSP, membrane-P, and NaHCO3-P, were effectively stabilized by ferrous sulfate (FeSul), calcium oxide (CaO), or aluminum sulfate (alum). After applying the stabilized BS, or fresh BS (FBS), FBS compost (BSC), or P fertilizer (KH2PO4) to an alluvial soil, P availability was probed during 100 days of incubation. A plant-based bioassay indicated that P availability followed the order KH2PO4 >> alum-BS > BSC ≥ FBS > CaO-BS >> FeSul-BS. The WSPi concentration in soil increased following FBS or BSC application, and P mineralization further increased it during incubation. In contrast, the chemically stabilized BS reduced WSPi concentrations relative to the untreated soil. It was concluded that the chemically stabilized BS effectively controlled WSPi in the soil while still supplying P to support plant growth. Using the sequential extraction procedure the persistence of P availability in BS treated soils was shown to be of a long-term nature. 15 years after the last BS application to MN soils that were annually amended for 20 years by heavy rates of BS, about 25% of the added BS-P was found in the labile fractions. The UMN group further probed soil-P speciation in these soils by bulk and micro X-ray absorption near edge structure (XANES). This newly developed method was shown to be a powerful tool for P speciation in soils. In a control soil (no BS added), 54% of the total P was PO and it was mostly identified as phytic acid; 15% was identified as brushite and 26% as strengite. A corn crop BS amended soil included mostly P-Fe-peat complex, variscite and Al-P-peat complex but no Ca-P while in a BS-grass soil octacalcium phosphate was identified and o-phosphorylethanolamine or phytic acid was shown to dominate the PO fraction.