Zeitschriftenartikel: „Acid water stripping“

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Duan, Ning, Yao Wen Gao, Teng Zhang, Ke Ming Wu und Yin Feng Zhang. „Study on Water-Based Paint Stripper for Tinplate“. Advanced Materials Research 690-693 (Mai 2013): 2071–75. http://dx.doi.org/10.4028/www.scientific.net/amr.690-693.2071.

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A novel water-based paint stripper was prepared for white, metallic ink and varnish coated on the tinplate steel surface. The effect of accelerator and surfactant on stripping efficiency was investigated with the types and dosage of the accelerator and surfactant, the stripping temperature and stirring up condition. The highest stripping efficiency was achieved with the stripper composited by (mass fraction) 35% benzyl alcohol, 6% propanediol carbonate, 10% formic acid, 2% cetyl tri-methyl ammonium bromide (CTMAB) and 47% distilled water, respectively. This paint stripper had low volatility, and was not easy to burn. Scanning electron microscopy (SEM) test indicated that the paint stripper had little corrosive effect on tinplates.

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Tao, Wendong, Anayo T. Ukwuani und Fred Agyeman. „Recovery of ammonia in anaerobic digestate using vacuum thermal stripping – acid absorption process: scale-up considerations“. Water Science and Technology 78, Nr. 4 (16.08.2018): 878–85. http://dx.doi.org/10.2166/wst.2018.360.

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Abstract A vacuum thermal stripping process coupled with acid absorption has been developed at laboratory scale to recover ammonia in anaerobic digestate. To make this ammonia recovery process scalable, this study investigated the effects of feed depth on vacuum thermal stripping in a pilot system, developed sodium hydroxide dosages required to raise feed pH for stripping, and simulated the dynamics of ammonia reduction in batch stripping tests. As feed depth was increased from 8.5 to 34.0 cm, the ammonia mass transfer coefficient and ammonia stripping efficiency decreased while the mass of stripped ammonia increased. Digested municipal sludge had a greater ammonia mass transfer coefficient than digested dairy manure at each feed depth, which could be attributed to the difference in suspended and dissolved solids concentrations. The optimum feed depth was 18 cm of the digested sludge and 14 cm of the digested manure. Sodium hydroxide dosage for the digested manure was higher than that for the digested sludge and co-digested foodwaste. The dosages were correlated to concentrations of total dissolved solids and ammonia. Total ammonia concentration decreased exponentially in batch stripping of the digested sludge at 25.5 cm deep, with a first-order stripping rate coefficient of 0.087–0.144 h−1.

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Rajendran, V., S. M. Saufi, M. A. K. Zahari und A. W. Mohammad. „Study on stripping phase conditions on the levulinic acid extraction using supported liquid membrane“. Journal of Mechanical Engineering and Sciences 13, Nr. 3 (27.09.2019): 5625–36. http://dx.doi.org/10.15282/jmes.13.3.2019.25.0451.

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Supported liquid membrane (SLM) is the most effective technique to extract and recover the desired product from the biomass products in a single step. The study of the operation parameters in SLM system is very important to improve the yield of extraction and recovery of the product. In this study, different types of stripping agents such as sodium hydroxide (NaOH), sodium carbonate, hydrochloric acid, trimethylamine, and water were tested in the SLM system to extract levulinic acid (LA). By using 0.3 M trioctylamine in 2-ethyl-1-hexanol as liquid membrane phase, it was found that NaOH was the best stripping agent to extract LA. The concentration of the NaOH stripping agent was varied from 0.25 M to 1 M. The best stripping agent concentration was 0.5 M, which gave an LA extraction of 86% from a 10 g/L LA aqueous solution. The flow rate of the feed and stripping phase was investigated from 25 mL/min to 125 mL/min. SLM operated at 75 L/min was found to be adequate in reducing the boundary layer thickness at both sides of the SLM phases without any leakage of the liquid membrane and breakage of the matrix support. At the best stripping condition, 89% of the LA was extracted using 0.5 M NaOH that operated at flow rate of 75 mL/min.

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Fayyad, Manar. „Indirect trace determination of nitrilotriacetic acid in water by potentiometric stripping analysis“. Analytical Chemistry 59, Nr. 1 (Januar 1987): 209–11. http://dx.doi.org/10.1021/ac00128a046.

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Le Gall, Anne-Christine, und Constant M. G. van den Berg. „Determination of folic acid in sea water using adsorptive cathodic stripping voltammetry“. Analytica Chimica Acta 282, Nr. 3 (Oktober 1993): 459–70. http://dx.doi.org/10.1016/0003-2670(93)80109-x.

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Jagtap, Neha, und Treavor H. Boyer. „Integrated, multi-process approach to total nutrient recovery from stored urine“. Environmental Science: Water Research & Technology 4, Nr. 10 (2018): 1639–50. http://dx.doi.org/10.1039/c8ew00004b.

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Li, S. J., L. Zhang, H. I. Chen, H. Chai und C. J. Gao. „Complex extraction and stripping of H acid wastewater“. Desalination 206, Nr. 1-3 (Februar 2007): 92–99. http://dx.doi.org/10.1016/j.desal.2006.02.061.

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Komy, Z., E. Roekens und R. van Grieken. „Analysis of rain water by differential-pulse stripping voltammetry in nitric acid medium“. Analytica Chimica Acta 204 (1988): 179–87. http://dx.doi.org/10.1016/s0003-2670(00)86357-6.

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9

Fayyad, Manar, Maha Tutunji und Ziad Taha. „Indirect Trace Determination of Ethylenediminetetraacetic Acid (Edta) in Water by Potentiometric Stripping Analysis“. Analytical Letters 21, Nr. 8 (August 1988): 1425–32. http://dx.doi.org/10.1080/00032718808059874.

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Wang, Jiang-Bo, Rui-Jing Zhang, Zhong-Gui Mao, Dong-Sheng Xue, Zheng-Jun Zhu, Han-Chao Yu, Feng-Jiao Cai, Lin-Yang Cai, Jia-Wei Bao und Jian Xu. „Full recycling of citric acid wastewater through anaerobic digestion, air-stripping and pH control“. Water Science and Technology 80, Nr. 6 (15.09.2019): 1196–204. http://dx.doi.org/10.2166/wst.2019.364.

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Abstract Anaerobic digestion effluent (ADE) from the anaerobic digestion treatment of citric acid wastewater can be reused as a potential substitute for process water in the citric acid fermentation. However, excessive sodium contained in ADE significantly decreases citric acid production. In this paper, the inhibition mechanism of sodium on citric acid fermentation was investigated. We demonstrated that excessive sodium did not increase oxidative stress for Aspergillus niger, but reduced the pH of the medium significantly over the period 4–24 h, which led to lower activities of glucoamylase and isomaltase secreted by A. niger, with a decrease of available sugar concentration and citric acid production. ADE was pretreated by air-stripping prior to recycle and 18 g/L calcium carbonate was added at the start of fermentation to control the pH of the medium. The inhibition caused by ADE was completely alleviated and citric acid production substantially increased from 118.6 g/L to 141.4 g/L, comparable to the fermentation with deionized water (141.2 g/L). This novel process could decrease wastewater discharges and fresh water consumption in the citric acid industry, with benefit to the environment.

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Thị Hue, Nguyen, Nguyen Van Hop, Hoang Thai Long, Nguyen Hai Phong, Tran Ha Uyen, Le Quoc Hung und Nguyen Nhi Phuong. „Determination of Chromium in Natural Water by Adsorptive Stripping Voltammetry Using In Situ Bismuth Film Electrode“. Journal of Environmental and Public Health 2020 (14.05.2020): 1–15. http://dx.doi.org/10.1155/2020/1347836.

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Development of adsorptive stripping voltammetry (AdSV) combined with in situ prepared bismuth film electrode (in situ BiFE) on glassy carbon disk surface using diethylenetriamine pentaacetic acid (DTPA) as a complexing agent and NO3− as a catalyst to determine the trace amount of chromium (VI) is demonstrated. According to this method, in the preconcentration step at Edep = −800 mV, the bismuth film is coated on the surface of glassy carbon electrodes simultaneously with the adsorption of complexes Cr(III)-DTPA. In addition to the influencing factors, the stripping voltammetry performance factors such as deposition potential, deposition time, equilibration time, cleaning potential, cleaning time, and technical parameters of differential pulse and square wave voltammetries have been investigated, and the influence of Cr(III), Co(II), Ni(II), Ca(II), Fe(III), SO42−, Cl−, and Triton X has also been investigated. This method gained good repeatability with RSD <4% (n = 9) for the differential pulse adsorptive stripping voltammetry (DP-AdSV) and RSD < 3% (n = 7) for the square wave adsorptive stripping voltammetry (SqW-AdSV), and low limit of detection: LOD = 12.10−9 M ≈ 0.6 ppb (at a deposition potential (Edep) of −800 mV and the deposition time (tdep) of 50 s) and LOD = 2.10−9 M ≈ 0.1 ppb (at Edep = −800 mV and tdep = 160 s) for the DP-AdSV and SqW-AdSV, respectively. This method has been successfully applied to analyze chromium in natural water.

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Rochte, Jacob, und Kris Berglund. „Preliminary Studies on the Use of Reactive Distillation in the Production of Beverage Spirits“. Beverages 5, Nr. 2 (02.04.2019): 29. http://dx.doi.org/10.3390/beverages5020029.

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Distilled alcoholic beverages have been produced through fermentation and distillation for centuries but have not purposefully involved a chemical reaction to produce a flavoring. Introducing a microorganism to produce butyric acid along with the typical yeast ethanol fermentation sets up a reactive distillation system to flavor a spirit with ethyl butyrate and butyric acid. The ternary interactions of water, ethanol, and butyric acid allow all three to vaporize in the stripping distillation, thus they are concentrated in the low wines and give a large excess of ethanol compared to butyric acid for better reaction completion. The stripping distillation has also been modeled on Aspen Plus® V9 software (by Aspen Technology, Inc. Bedford, MA, USA) and coincides well with a test stripping distillation at the bench scale. Amberlyst® 15 wet catalyst was added to a subsequent distillation, resulting in the production of the desired ethyl butyrate in the distillate, measured by gas chromatography. Primary sensory evaluation has determined that this process has a profound effect on the smell of the spirit with the main flavor being similar to fruity bubble gum. The current results will provide a pathway for creating spirits with a desired flavor on demand without acquiring a heavy capital cost if a beverage distillation column is already purchased.

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Yang, K., C. Oh und S. Hwang. „Optimizing volatile fatty acid production in partial acidogenesis of swine wastewater“. Water Science and Technology 50, Nr. 8 (01.10.2004): 169–76. http://dx.doi.org/10.2166/wst.2004.0512.

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This research has been conducted based on the fact that acetic and butyric acids are favorable substrates for methanogens, and that a low level of propionic acid production during acidogenesis minimizes the inhibition effect on methanogenic growth. Raw swine wastewater was pretreated with ammonia stripping to enhance acidogenesis. The ammonia nitrogen concentration of less than 1.2 g/L did not significantly affect the biochemical acidogenic potential of swine wastewater. For acidogenesis of swine wastewater, a et of experiments were carried out to produce short chain volatile fatty acids (VFA) in laboratory-scale continuously stirred tank reactors. The production of acetic, propionic, and butyric acids associated with simultaneous changes in hydraulic retention time (HRT) and temperature was investigated. Response surface methodology was successfully applied to approximate the responses of the VFA productions. The optimum physiological conditions where the maximum acetic and butyric acids production occurred were 2.4 days HRT at 34°C and 2.1 days HRT at 35°C, respectively. The propionic acid production linearly increased as both HRT and temperature increased.

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Li, Li, Xiyan Zheng, Chunjiao Pan, Hao Pan, Zhongqiu Guo, Bingmi Liu und Yu Liu. „A pH-sensitive and sustained-release oral drug delivery system: the synthesis, characterization, adsorption and release of the xanthan gum-graft-poly(acrylic acid)/GO–DCFP composite hydrogel“. RSC Advances 11, Nr. 42 (2021): 26229–40. http://dx.doi.org/10.1039/d1ra01012c.

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Fontàs, Clàudia, Enriqueta Anticó und Victòria Salvadó. „Design of a Hollow Fiber Supported Liquid Membrane System for Zn Speciation in Natural Waters“. Membranes 8, Nr. 4 (27.09.2018): 88. http://dx.doi.org/10.3390/membranes8040088.

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A supported liquid membrane-hollow fiber system (HFSLM) has been developed to determine zinc speciation in aquatic environments. The liquid membrane consisted of an organic solution of bis-(2-ethylhexyl)phosphoric acid (D2EHPA) impregnated in the microporous of a polypropylene hollow fiber. The membrane contacted both the donor solution, that contained the metal and the stripping solution, placed in the lumen of the hollow fiber, where the metal was preconcentrated. Different parameters affecting the Zn2+ transport efficiency have been evaluated such as the composition of both the donor and stripping solutions as well as the membrane phase. Extraction and transport efficiencies of free Zn(II) higher than 90% were obtained with a liquid membrane consisting of a 0.1 M D2EHPA solution in dodecane and a 0.1 M HNO3 solution as the stripping phase. The developed HFSLM was used to study the effect of different ligands (EDTA and citric acid) in the donor phase of Zn(II) transport and to investigate the selectivity of the membrane towards Zn when other metals were also present. Finally, the HFSLM system was successfully applied to estimate the free Zn(II) concentrations in three water samples from a mining area. Moreover, the HFSLM system facilitates the analytical determination of trace Zn(II) levels allowing the achievement of enrichment factors of around 700 in the stripping phase.

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Alispahić, Amra, Adela Krivohlavek und Nives Galić. „Novel Preservation Methods for Inorganic Arsenic Speciation in Model and Natural Water Samples by Stripping Voltammetric Method“. Applied Sciences 11, Nr. 19 (22.09.2021): 8811. http://dx.doi.org/10.3390/app11198811.

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In this study, the preservation of As(III) in model solutions and natural groundwater samples from four locations in Croatia was conducted. Model laboratory samples were spiked with As(III) and As(V), and different complexing agents. Solutions were analysed in intervals of 24, 48 h and during ten days after preparation. Model samples containing citric acid, sodium citrate, sodium oxalate and potassium sodium tartrate in combination with acetic acid, spiked with As(III)and As(V), showed good species preservation. As(III), in model samples, was preserved for 7 days with citric acid, and citric acid in combination with acetic acid, as well as with tartrate. As(III), in natural samples, was preserved for 6 to 12 days with potassium sodium tartrate, citric acid, and citric acid in combination with acetic acid and showed improvement, compared with unpreserved samples (oxidation in 3 days). The results showed that acetic acid alone was not successful in preserving As speciation. Good resolution of inorganic arsenic species was achieved using differential pulse anodic stripping voltammetry technique (DPASV). Since this technique is comparatively cheaper and more convenient to use than other available techniques it could become a method of choice for arsenic speciation in water.

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Okada, M., Y. Nakano, K. Ohkawa, T. Y. Tsai und W. Nishijima. „Use of organic solution for the removal of hazardous chemicals: the more efficient and zero-emission decomposition processes by extraction, concentration and reaction in organic solutions“. Water Supply 4, Nr. 1 (01.02.2004): 119–25. http://dx.doi.org/10.2166/ws.2004.0014.

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We proposed a new process for ozone decomposition of hazardous chemicals in organic solution concentrated from water into the solution by using adsorbent or air-stripping. The target compounds studied were chlorophenols and TCE. Chlorophenols were adsorbed from water and desorbed into organic solutions like acetic acid by GAC and synthetics adsorbents, SP850 and SP207. The best adsorbent both for adsorption and desorption into acetic acid solution was synthetis one, SP850, and percent desorption was 100%. GAC was good for adsorption, but was not for desorption. Although more than 800 mg-TCE L−1 in acetic acid solution was decomposed by ozonation, little decrease in the decomposition rate was noted indicating that acetic acid can be reused for the next step of ozonation in the same acetic acid solution.

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Haritonovs, Viktors. „Evaluation of polyaminoamide as a surfactant additive in hot mix asphalt“. Baltic Journal of Road and Bridge Engineering 10, Nr. 2 (25.06.2015): 112–17. http://dx.doi.org/10.3846/bjrbe.2015.14.

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The phenomenon of breaking the bond between the aggregates and the bitumen is known as stripping. Strip-ping of asphalt films from the surface of aggregate particles results in premature failure of asphalt pavement. This causes weakening of pavement resistance to rutting and fatigue. Furthermore, moisture damage increases the susceptibility of pavement to reveling, a distress that causes the loss of skid resistance on surface of the road and deterioration of pavement. Surfactant additive or adhesive agent is a surface-active agent that changes (lowers) the surface tension of rock materials. Introduction of surfactant additive results in increased strength of adhesive bond between bitumen and the rock materials surface preventing stripping throughout the service life of the asphalt concrete. Polyaminoamide is an organic water soluble compound that allows waterproofing mineral aggregate surfaces and acts as a bonding agent to bitumen. The objective of this research is to study the effect of polyaminoamide based and pholiphosphoric acid based liquid additives on stripping, moisture susceptibility, rutting and fatigue performance of asphalt concrete. In this paper, boiling water test was used to determine the percentage of stripped aggregates after boiling. The moisture susceptibility of asphalt mixtures was investigated by means of testing the retained indirect tensile strength after water immersion using Marshal stability test method. Wheel tracking test was also conducted on asphalt slabs prepared in the laboratory to determine rut resistance. Asphalt concrete with commonly used mineral filler was chosen as a control mixture. It was found that the adhesion additive not only improves stripping resistance, but also slightly improves asphalt rut resistance.

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Huang, Donggen, Tianzi Yang, Zhuanghong Mo, Qin Guo, Shuiqing Quan, Cui Luo und Lei Liu. „Preparation of Graphene/TiO2Composite Nanomaterials and Its Photocatalytic Performance for the Degradation of 2,4-Dichlorophenoxyacetic Acid“. Journal of Nanomaterials 2016 (2016): 1–11. http://dx.doi.org/10.1155/2016/5858906.

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The graphene (GR) was prepared by an improved electrochemical stripping method using a high-purity graphite rod as raw material and high temperature heat reduction in hydrogen atmosphere, and the graphene/TiO2(GR/TiO2) composite nanomaterials were manufactured by the method of sol-gel and high temperature crystallization in hydrogen atmosphere using butyl titanate and electrolysis graphene as precursors. The physical and chemical properties of the composites had been characterized by using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), UV-Vis spectrophotometer (UV-Vis), scanning electron microscopy (SEM), Transmission Electron Microscope (TEM), and specific surface area (SSA) by BET method. The photocatalytic properties of GR/TiO2composites nanomaterials in anoxic water were studied by using 2,4-dichlorophenoxyacetic acid (2,4-D) as probe. The results showed that graphite was well intercalated and peeled by a facile electrolysis method in different electric field environment; a well dispersed and rings structure of graphene was prepared by coupling ultrasound-assisted changing voltage electrochemical stripping technology. The as-prepared GR/TiO2composites had good performance for the photocatalytic degradation of 2,4-D in anoxic water; the chlorines were removed from benzene ring; the middle products of dichlorophenol, chlorophenol, phloroglucinol, and so forth were produced from the photocatalytic redox reaction of 2,4-D in anoxic water; parts of 2,4-D were decomposed completely, and CO2and H2O were produced.

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Mikeli, Eleni, Efthimios Balomenos und Dimitrios Panias. „Utilizing Recyclable Task-Specific Ionic Liquid for Selective Leaching and Refining of Scandium from Bauxite Residue“. Molecules 26, Nr. 4 (04.02.2021): 818. http://dx.doi.org/10.3390/molecules26040818.

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Ionic liquids (ILs) have attracted great interest in the field of extractive metallurgy mainly because they can be utilized in low temperature leaching processes where they exhibit selectivity and recyclability. A major drawback in mixed aqueous-IL systems, is IL dissolution in the aqueous phase, which leads to IL losses, increasing the overall processing cost. This study advances the method for recovering scandium (Sc) from bauxite residue (BR) using as leaching agent the IL betainium bistriflimide, [Hbet][Tf2N] mixed with water, which has been reported in previous publications. Ionic liquid leachate (IL-PLS) was prepared by leaching BR with a mixture of [Hbet][Tf2N]-H2O and subjected to different stripping experiments using hydrochloric acid. The advancement, presented in this work, is related with the optimization of the metal extraction (stripping) from the IL-PLS, where an aqueous solution with high Sc concentration and minimum metal impurities and minimum IL co-extraction is produced. It is further proven that the metal cation extraction is defined by the stoichiometry of the acidic solution and the dissolution (losses) of the IL in the aqueous phase can be minimized by adjusting the volume ratio and the acid concentration. A two-step stripping process described, achieves the selective increase of Sc concentration by 8 times in the aqueous solution, while maintaining cumulative IL losses to similar levels as the optimum 1 step non-Sc selective stripping process.

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Nijhuis, T. A., A. E. W. Beers, F. Kapteijn und J. A. Moulijn. „Water removal by reactive stripping for a solid-acid catalyzed esterification in a monolithic reactor“. Chemical Engineering Science 57, Nr. 9 (Mai 2002): 1627–32. http://dx.doi.org/10.1016/s0009-2509(02)00039-8.

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Wasąg, Joanna, und Malgorzata Grabarczyk. „The determination of titanium contained in Tytanit biostimulant employed to improve crops performance in natural environmental samples“. Annales Universitatis Mariae Curie-Sklodowska, sectio AA – Chemia 71, Nr. 2 (03.04.2017): 115. http://dx.doi.org/10.17951/aa.2016.71.2.115.

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<p>The purpose of this work was to determinate the amount of titanium in different environmental water samples spiked with crop biostimulant Tytanit. The measurements were conducted using adsorptive stripping voltammetry (AdSV). The titanium complex with chloranilic acid was accumulated on mercury film silver based electrode (Hg(Ag)FE) at the potential -0.3 V. The analysis of natural water samples enriched with Tytanit, collected in the eastern part ofPolandconfirms that this procedure is fast and essential for the determination of titanium in environmental water samples.</p>

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Anwar, Sohaib Waseem, und Wendong Tao. „Cost benefit assessment of a novel thermal stripping – acid absorption process for ammonia recovery from anaerobically digested dairy manure“. Water Practice and Technology 11, Nr. 2 (01.06.2016): 355–64. http://dx.doi.org/10.2166/wpt.2016.041.

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Thermal stripping – acid absorption is a novel technology recently developed to recover ammonia as marketable ammonium sulfate granules from anaerobic digester effluent. Taking a large-size dairy farm in New York State, USA, as an example, this study evaluates the costs and benefits of ammonia recovery from a recirculation line of mesophilic anaerobic digesters. Option 1 is the baseline without ammonia recovery. Option 2 is to draw digester effluent at 28% of the liquid manure loading rate, heat to 101 °C for ammonia recovery, and return the ammonia-recovered dairy manure to the digesters. Under option 2, the returned hot manure eliminates the need to heat the digesters. Option 3 is similar to Option 2, but the recirculation rate is only 14% of the manure loading rate. In this case, additional heating is needed for the digesters. Engineering unit cost and revenue models are developed for the thermal stripping – acid absorption process. Options 2 and 3 have benefit/cost ratios of 1.90 and 1.86, respectively. Option 2 produces greater net present value (NPV) ($1.34 million) than Option 2 ($0.72 million), while Option 1 yields a negative NPV (−$0.23 million). Ammonia recovery on this farm can create 1.5–3 jobs. Labor costs account for 62–70% of the total operating costs. Option 2 can generate a benefit of $0.018/L manure digestate or $0.50/d/cow. Any uncertainties relating to NPV and benefit/cost ratio are mainly associated with the sale price of ammonium sulfate and hourly wage rate.

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Foxon, K. M., C. J. Brouckaert und A. Rozzi. „Denitrifying activity measurements using an anoxic titration (pHstat) bioassay“. Water Science and Technology 46, Nr. 9 (01.11.2002): 211–18. http://dx.doi.org/10.2166/wst.2002.0241.

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An anoxic titrimetric test was investigated for measuring denitrifying activity in an activated sludge system. The method measures the amount of acid that is required to maintain the pH set-point value in a batch denitrification experiment. An iterative algorithm was implemented to extract nitrate uptake rate (NUR) data from titration data, since the accumulation and depletion (stripping) of reaction by-products HCO3- and CO2 affects the direct calculation of denitrifying activity from titration data. This method was performed using an automatic pH-stat acid dosing system, and the data were analysed using the simulation software package, AQUASIM.

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Chiang, Pen-C., Chung-H. Hung, J. C. Mar und E. E. Chang. „Henry's constants and mass transfer coefficients of halogenated organic pollutants in an air stripping packed column“. Water Science and Technology 38, Nr. 6 (01.09.1998): 287–94. http://dx.doi.org/10.2166/wst.1998.0263.

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Both Henry's constants and volumetric mass transfer coefficients (KLa) of eight priority chlorinated organic compounds including 1,1-dichloroethene, methylene chloride, chloroform, carbon tetrachloride, 1,1,1-trichloroethane, trichloroethylene, tetrachloroethylene, and 1,4-dichlorobenzene in an air stripping packed column were investigated in this study. The liquid and gas phase EPICS (Equilibrium Partition in Closed System) and direct calculating methods were applied to determine the Henry's constants of VOCs. The interference of co-solute on Henry's constants was also investigated. Experimental results indicated that decrease in Henry's constants of VOCs was observed in the presence of humic acid but no apparent effect on Henry's constants was detected when there was NaCl and surfactant in solution. Four different configurations of packing media including Intalox Saddle, Super Intalox Saddle, Telleret, and Hedgehog made of polypropylene were respectively packed in the air stripping tower and investigated in the study. The dependence of hydraulic loading, air-water ratio, and configurations of packing media on mass transfer coefficients of VOCs was discussed.

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Ahmed, Ismail M., Romany N. Ammanoeil, Ebtissam A. Saad und Jacqueline A. Daoud. „Purification of Crude Phosphoric Acid and Leached Apatite by Solvent Extraction with CYANEX 923 in Kerosene“. Periodica Polytechnica Chemical Engineering 63, Nr. 1 (20.03.2018): 122–29. http://dx.doi.org/10.3311/ppch.11626.

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CYANEX 923 (a mixture of four trialkylphosphine oxides) in kerosene has been used for the extraction of phosphoric acid. Different parameters affecting the extraction of phosphoric acid such as shaking time, temperature, phase ratio O/A, extractant and phosphoric acid concentration were separately investigated. The stoichiometry of the extracted species was found to be H3PO4.L, where L refers to CYANEX 923. The stripping of the extracted species was found to be efficient with water. The obtained results were used for the recovery of phosphoric acid from both the crude acid and the leached solution from digestion of apatite phosphate rock with hydrochloric acid. Expanded Perlite was found to be efficient for the adsorption of uranium from both crude acid and the leached apatite.

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Nijhuis, T. A., A. E. W. Beers, F. Kapteijn und J. A. Moulijn. „Water Removal by Reactive Stripping for a Solid Acid Catalyzed Esteri fication in a Monolithic Reactor“. Chemie Ingenieur Technik 73, Nr. 6 (Juni 2001): 769. http://dx.doi.org/10.1002/1522-2640(200106)73:6<769::aid-cite7692222>3.0.co;2-p.

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Wu, Fangfang, Hongbin Lv, Xihong He, Zhongping Cheng, Hongwei Jia, Shubao Xie, Yuekun Liu, Guoan Ye und Hui He. „Selective Am(III) stripping with water-soluble PyTri-Diol in nitric acid from HDEHP organic phase“. Journal of Radioanalytical and Nuclear Chemistry 323, Nr. 1 (27.11.2019): 283–89. http://dx.doi.org/10.1007/s10967-019-06961-4.

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Zarębski, Jerzy, Andrzej Bobrowski, Agnieszka Królicka, Julia Gonciarczyk, Vasiliki Manolopoulou und Anastasios Economou. „A novel catalytic adsorptive stripping voltammetric method for the determination of germanium ultratraces in the presence of chloranilic acid and the V(IV)·HEDTA complex“. Journal of Solid State Electrochemistry 24, Nr. 11-12 (11.07.2020): 2891–99. http://dx.doi.org/10.1007/s10008-020-04669-0.

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Abstract A novel, sensitive catalytic adsorptive stripping voltammetric procedure which can be used to determine trace amounts of germanium is described. The method is based on the interfacial accumulation of the complex formed by Ge(IV) and the product of the reduction of chloranilic acid on the hanging mercury drop electrode or the renewable silver amalgam film electrode, and its subsequent reduction from the adsorbed state followed by the catalytic action of the V(IV)·HEDTA complex. The presence of V(IV)·HEDTA greatly enhances the adsorptive stripping response of Ge. The reduction of the Ge(IV) in the presence of chloranilic acid and V(IV)·HEDTA was investigated in detail and the effects of pH, electrolyte composition, and instrumental parameters were studied. Under optimal conditions, the catalytic peak current of germanium exhibited good linearity for Ge(IV) concentrations in the range of 0.75–60 nM (for 60 s of accumulation at −0.1 V, r2 = 0.995) and a low limit of detection (LOD = 0.085 nM). The procedure was successfully applied to determine Ge in water samples.

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Purwani, M. V., und Moch Setyadji. „Pengaruh Tri-n-Oktil Posfin Oksida dan Tingkat Ekstraksi pada Pemurnian Konsentrat Thorium“. EKSPLORIUM 36, Nr. 2 (30.11.2015): 109. http://dx.doi.org/10.17146/eksplorium.2015.36.2.2775.

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Telah dilakukan ekstraksi konsentrat thorium oksalat hasil olah monasit memakai ekstraktan Tri – n - Oktil Posfin Oksida (TOPO). Pengotor yang paling banyak terkandung dalam konsentrat thorium oksalat adalah cerium (Ce) dan lantanum (La). Tujuan penelitian ini adalah untuk memurnikan thorium (Th) dengan memisahkan Ce dan La dengan cara ekstraksi. Ekstraksi dilakukan secara batch dan bertingkat. Larutan umpan atau fase air adalah 10 gram konsentrat Th oksalat yang dilarutkan dalam 10,08 M HNO3 sehingga volume menjadi 100 mL dan fase organik adalah TOPO dalam kerosen. Stripping setiap tingkat ekstraksi dilakukan tiga kali, yaitu stripping pertama memakai air, stripping kedua memakai asam oksalat 5%, dan stripping ketiga memakai air. Waktu ekstraksi setiap tingkat 15 menit dan waktu stripping setiap tingkat 5 menit dengan perbandingan fase air dengan fase organik adalah 1 berbanding 1. Parameter yang diteliti adalah persentase TOPO dalam kerosen dan jumlah tingkat ekstraksi. Pemakaian TOPO dalam kerosen yang optimum 5% dan jumah tingkat ekstraksi 3. Pada ekstraksi I diperoleh konsentrat Ce dan pada tingkat ekstraksi II dan III diperoleh Th. Efisiensi ekstraksi Th tingkat II sebesar 39,76% dan efisiensi ekstraksi Th tingkat III 26,33%. Koefisien distribusi (Kd) Th tingkat ekstraksi II adalah 0,7587 dan Kd Th tingkat ekstraksi III 1,0096. Efisiensi ekstraksi Th total adalah 80,08 %, efisiensi ekstraksi Ce total 56,12%, efisiensi ekstraksi La total 1,54. Faktor pisah (FP) Th – Ce pada ekstraksi I adalah 1,00, FP Th – La pada ekstraksi I 92,07, FP Th – Ce pada ekstraksi II adalah 250,24 dan FP Th – La pada ekstraksi II adalah ∞, FP Th – Ce pada ekstraksi III 124,22 dan FP Th – La pada ekstraksi III adalah ∞. Faktor pisah total Th – Ce sebesar 1,4270 dan Faktor pisah total Th – La 47,0459. Kadar Th oksalat pada ekstraksi II sebesar 97,06%, kadar Th oksalat pada ekstraksi III 98,00 %. The extraction of thorium oxalate concentrate as processing product of monazite using Tri Octyl Posfine Oxide (TOPO) has been done. The most impurities contained in thorium oxalate concentrate are Ce (cerium) and La (lanthanum). The purpose of this study is to purify Th by separating Ce and La using extraction process. The extraction is done by bacth and multistage. The solution of feed or water phase is 10 grams of Th oxalate concentrate dissolved in 10.08 M HNO3 so that the volume becomes 100 mL and the organic phase is TOPO in kerosene. Stripping in each stage conducted three times, first stripping use water, second stripping use 5 % oxalic acid and the third stripping use water. Extraction time at every stage is 15 minutes and stripping time at every stage is 5 minutes with ratio of aqueous phase to organic phase = 1 : 1 . The parameters were studied % TOPO - kerosene and number of extraction stage. The optimum usage of TOPO in kerosene is 5 %. On extraction I obtained Ce concentrate and on extraction II and III obtained Th concentrates. The extraction II efficiency of Th is 39.76 % and extraction III efficiency of Th is 26.33 % . Coefficient of distribution (Kd) of Th in stage II is 0.7587 and Kd of Th in stage III is 1.0096. Total extraction efficiency of Th is 80.08 %, total extraction efficiency of Ce is 56.12 %, and total extraction efficiency of La is 1.54 %. The separation factor of Th – Ce in extraction I is 1.00 and separation factor of Th – La in extraction I is 92.0, separation factor of Th – Ce in extraction II is 250.24, and separation factor of Th – La in extraction II is ∞. Separation factor of Th – Ce in extraction III is 124.22 and separation factor of Th – La in extraction III is ∞. Total separation factor of Th – Ce is 1.4270 and total separation factor of Th – La is 4.0459. The content of Th oxalate in stripping product from the extraction II is 97.06 % and in stripping product from the extraction III is 98.00%.

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Huang, Jun Feng, Shao Peng Wu, Li Xing Ma und Zhi Fei Liu. „Material Selection and Design for Moisture Damage of HMA Pavement“. Materials Science Forum 614 (März 2009): 269–74. http://dx.doi.org/10.4028/www.scientific.net/msf.614.269.

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Moisture damage is a primary mode of distress occurring in hot mix asphalt (HMA) pavements. Usually, the acid aggregate like gneiss must use some anti-stripping additive to resist water damage. Hydrated lime is best known as an anti-stripping additive since 1910. The purpose of this paper is to look at some aspects of the effects of aggregate chemical properties and hydrated lime on the dynamic mechanics and stripping behavior of hot mix asphalt. Two types of aggregates evaluated in this study were limestone and gneiss. The effects of the aggregates type were evaluated on four different aggregate gradations which were composed with the two aggregates in different proportion. And the hydrated lime has been used for HMA pavements to mitigate moisture-related damage in gneiss asphalt mixture. Laboratory tests for different asphalt mixture include Marshall Test, Frozen-thaw Cycle Test, Dynamic Modulus Test (DMT) and Indirect Tensile Fatigue Test (ITFT). Testing data and analyses demonstrated that different aggregate gradations have different mechanical properties. Hydrate lime has greatly contributed to moisture damage resistance in acid aggregate gneiss and enhanced the dynamic modulus. The modified with hydrated lime mixture composed with coarse gneiss aggregate and fine limestone aggregate also has better performance of the mixture against rutting, fatigue and thermal cracking. It can be concluded from ITFT tests that the fatigue life (load cycle times) of additive hydrated lime asphalt concrete is more than neat ones. At last, we can conclude that the selection and design that modified with hydrated lime and fine limestone aggregate replace acid aggregate could create multiple benefits in asphalt mixtures.

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Yan, Taihong, Chen Zuo, Weifang Zheng, Guoan Ye und Xiaorong Wang. „Kinetics of reductive stripping of Pu(IV) in the tributylphosphate-kerosene/nitric acid-water system using dihydroxyurea“. Journal of Radioanalytical and Nuclear Chemistry 280, Nr. 3 (27.04.2009): 585–88. http://dx.doi.org/10.1007/s10967-009-7482-x.

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Zhang, Hai Yan, Jin Yang, Da Zeng Ming und Zhi Xiang Li. „Experimental Study on De-Fluorinating by Adding Dilute Alkali in Wet Phosphoric Acid Extraction Organic Phase“. Applied Mechanics and Materials 662 (Oktober 2014): 46–50. http://dx.doi.org/10.4028/www.scientific.net/amm.662.46.

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Possible ways to remove fluoride from phosphoric acid are extraction,but there are always generated a second organic phase ,where still have small amounts of impurities such as fluoride,sulfate,iron,aluminum and heavy metals. The traditional process using pure water or dilute phosphoric acid washing the organic phase to get phosphoric acid ,but the impurities removing rate is not obvious.This study explore a new way to changes the washing detergent,using dilute alkali solution to reduce fluoride content of stripping in phosphoric acid.The optimization of experimental conditions is dilute alkali mass fraction 20%,dosage 0.4%,temperature 45°C,the defluorization rate can be 67.75% and phosphorus pentoxide yield rise to 95.50%.This study provides a new idea to improve defluorination rate in industrial production.

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Bi, Qiang, Juanqin Xue, Yingjuan Guo, Guoping Li und Haibin Cui. „A two-step approach for copper and nickel extracting and recovering by emulsion liquid membrane“. Water Science and Technology 74, Nr. 10 (13.09.2016): 2454–61. http://dx.doi.org/10.2166/wst.2016.393.

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The recycling of copper and nickel from metallurgical wastewater using emulsion liquid membrane (ELM) was studied. P507 (2-ethylhexyl phosphonic acid-2-ethylhexyl ester) and TBP (tributyl phosphate) were used as carriers for the extraction of copper and nickel by ELMs, respectively. The influence of four emulsion composition variables, namely, the internal phase volume fraction (ϕ), surfactant concentration (Wsurf), internal phase stripping acid concentration (Cio) and the carrier concentration (Cc), and the process variable treat ratio on the extraction efficiencies of copper or nickel were studied. Under the optimum conditions, 98% copper and nickel were recycled by using ELM. The results indicated that ELM extraction is a promising industrial application technology to retrieve valuable metals in low concentration metallurgical wastewater.

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Alemayehu, Denekew, Bhagwan Singh Chandravanshi Chandravanshi, Tesfu Hailu und Merid Tessema. „Square wave anodic stripping voltammetric determination of Hg(II) with N-p- chlorophenylcinnamohydroxamic acid modified carbon paste electrode“. Bulletin of the Chemical Society of Ethiopia 34, Nr. 1 (24.04.2020): 25–39. http://dx.doi.org/10.4314/bcse.v34i1.3.

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A new method has been developed for the electrochemical determination of Hg(II) with N-p-chlorophenylcinnamohydroxamic acid (CPCHA) modified carbon paste electrode by square wave anodic stripping voltammetry (SWASV). Hg(II) was accumulated on the electrode surface by the formation of the complex in an open circuit and the resulting surface was characterized by electrochemical reduction and stripping. The optimum voltammetric response was observed using a carbon paste composition of 7.5% (w/w) CPCHA and preconcentration time of 210 s in 0.1 M sodium acetate at pH 8 followed by electrochemical SWASV in 0.3 M NH4Cl solution at pH 4 at a reduction potential of -0.6 V. The voltammetric signals were linear in the range of 1-25 µM Hg(II) with a detection limit of 12.9 nM. The voltammetric response for six replicate measurements of 15 µM Hg(II) was reproduced with 3.8% relative standard deviation (RSD). Many coexisting metal ions had little or no effect on the determination of Hg(II). Five spiked samples of water were evaluated by using the developed method giving recoveries of Hg(II) in the range 98-105%. Bull. Chem. Soc. Ethiop. 2020, 34(1), 25-39. DOI: https://dx.doi.org/10.4314/bcse.v34i1.3

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Fu, Haiqing, Shuo Liu, Lanlin Yi, Hong Jiang, Changjiu Li und Yongjun Chen. „A Durable and Self-Cleaning Superhydrophobic Surface Prepared by Precipitating Flower-Like Crystals on a Glass-Ceramic Surface“. Materials 13, Nr. 7 (02.04.2020): 1642. http://dx.doi.org/10.3390/ma13071642.

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Herein, a superhydrophobic surface with superior durability was fabricated on a glass-ceramic surface by crystallization, hydrofluoric acid (HF) etching, and surface grafting. The as-prepared glass-ceramic surface was composed of three-dimensional flower-like micro-clusters, which were self-assembled from numerous nanosheets. Such a dual-scale rough surface exhibited superhydrophobicity, with a water contact angle (WCA) of 170.3° ± 0.1° and a sliding angle (SA) of ~2° after grafting with 1H, 1H, 2H, 2H-perfluorodecyltriethoxysilane (FAS-17). This can be attributed to the synergistic effect between the dual-scale structure and surface chemistry. Furthermore, this surface exhibited excellent self-cleaning properties, stability against strong acid and strong alkali corrosion, and anti-stripping properties.

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Rensink, J. H., H. J. G. W. Donker und T. S. J. Simons. „Phosphorus Removal at Low Sludge Loadings“. Water Science and Technology 17, Nr. 11-12 (01.11.1985): 177–86. http://dx.doi.org/10.2166/wst.1985.0231.

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Pilot plant studies for phosphorus removal with settled domestic waste water at low loadings resulted in 40–50 % P-removal. Addition of 100 mg acetic-acid-COD per liter waste water at low sludge loadings showed a P-removal of more than 97,5 %, even at long periods of rainfall. Instead of dosing acetic acid, experiments were carried out by prolongation of the sludge retention time in the anaerobic zone to promote production of low fatty acids. Half an hour stirring followed by three hours non-stirring of the anaerobic zone improved the P-uptake to 79 %. Seeing that the last-mentioned method did not lead to P-effluent values of less than 1 mg/1 biological P-removal experiments were carried out supported by partly P-stripping of the sludge. The P-effluent content dropped to a constant value of 0,4 mg P/l or more than 97,5 % P-removal. Also during long periods of rainfall the P-effluent value remained 0,4 mg P/l. The investigation is in full progress and focused on studying parameters to shorten the sludge retention time in the stripper tank.

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Abbasi, Shahryar, Masoumeh Rostamniya und Hossein Khani. „Simultaneous determination of trace lead and cadmium in water samples by adsorptive stripping voltammetry using gallic acid as a selective chelating agent“. Water Supply 15, Nr. 5 (08.06.2015): 1152–58. http://dx.doi.org/10.2166/ws.2015.050.

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This work describes a procedure for the simultaneous determination of cadmium and lead in some food and water samples using an adsorptive stripping voltammetric method. The method is based on the adsorptive accumulation of 2,3,4-trihydroxybenzoic acid (gallic acid (GA)) complexes of these elements onto a hanging mercury drop electrode, followed by the reduction of the adsorbed species. Optimal analytical conditions were found to be 0.10 M borate buffer (pH 6.2), 2.5 × 10−5 M GA, an accumulation potential of – 0.1 V (Versus SCE), an accumulation time of 80 s and a scan rate of 60 mV/s. The peak current is proportional to the concentration of lead and cadmium over the range of 0.50–70.00 ng mL−1 and 0.20–35.00 ng mL−1, respectively, and the detection limit is 0.014 ng mL−1 and 0.011 ng mL−1 for lead and cadmium, respectively, for a 80 s adsorption time. The propose method was applied to the determination of lead and cadmium in water and food samples with satisfactory results.

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Etorki, A. M., Labib A. Awin, M. El-Rais, M. S. Elhabbat und I. S. Shaban. „Application of Gold Nanoparticles with 1,6-Hexanedithiol Modified Screen-Printed Carbon Electrode as a Sensor for Determination of Arsenic in Environmental Samples“. Sensor Letters 17, Nr. 10 (01.10.2019): 762–68. http://dx.doi.org/10.1166/sl.2019.4144.

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We have described the development of electrochemical nano sensor for the detection of total arsenic in groundwater, soil, food and honey samples based on the formation of gold nanoparticles. Screen printed carbon electrodes were modified with gold nanoparticles and linked with 1,6-hexanedithiol self-assembled monolayers. The electrodeposition of Au nanoparticles was applied in 10 mL of the solution that totally cover the screen-printed carbon electrode while applying a constant potential of –0.4 V (vs. Ag within SPCE) for 600 sec. Cyclic voltammetry was used to characterize the gold nanoparticles before and after modified with 1,6-hexanedithiol self-assembled monolayers on screen printed carbon electrode. Square wave anodic stripping voltammetry with multi point standard addition method was examined for the detection of As(III) and As(V) on Au NPs-1,6-hexanedithiol modified screen printed carbon electrode under optimized conditions. As(III) and As(V) was firstly, deposited for 60 seconds by the reduction of arsenic in buffer solution: (citric acid, sodium chloride and ascorbic acid pH 2.0), followed by As stripping between –0.20 and 0.35 V at the following parameters: scan rate: 100 mV s–1, frequency: 60 Hz, amplitude: 0.025 V and increment: 5.0 mV. it was found that Au-NPs with 1,6-hexanedithiol modified screen-printed carbon electrode had a highest anodic stripping peak current at 0.201 V. The limit of detection value for arsenic was identified to be 1.7 ng ml –1. Also, the electrochemical nanosensor showed excellent reproducibility and high stability. The developed method was successfully applied to detect total arsenic in ground water, soil and honey samples.

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Stas, Jamal, und Marwa Yousef. „Extraction of Lactic Acid from Whey of Yoghurt by Solvent Extraction Technique“. Revista de Chimie 72, Nr. 3 (29.07.2021): 102–11. http://dx.doi.org/10.37358/rc.21.3.8441.

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The aim of this paper is to investigate the possibility to recover lactic acid (LA) from the whey of yoghurt by easy and effective solvent extraction technique using tri-n-octylamine, tri-n-butyl phosphate, and their mixtures as extractant. All parameters affecting the transfer of lactic acid to the organic phase were investigated including: time of stirring, tri-n-butyl phosphate and tri-n- octylamine concentrations, organic to aqueous phase ratio, temperature, NaCl concentration as a salting out agent, and number of contacts. The maximum yield of LA extraction can be obtained by using the following operation conditions: 0.8M TOA+11% TBP, Vorg/Vaq = 4/1, t = 30 oC, [NaCl] = 2M. Complete stripping of LA from loaded organic phase can be done in 2 stages using double distilled water at 60oC and Vaq/Vorg = 20/1.

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Imokawa, Genji. „Cutting Edge of the Pathogenesis of Atopic Dermatitis: Sphingomyelin Deacylase, the Enzyme Involved in Its Ceramide Deficiency, Plays a Pivotal Role“. International Journal of Molecular Sciences 22, Nr. 4 (05.02.2021): 1613. http://dx.doi.org/10.3390/ijms22041613.

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Atopic dermatitis (AD) is characterized clinically by severe dry skin and functionally by both a cutaneous barrier disruption and an impaired water-holding capacity in the stratum corneum (SC) even in the nonlesional skin. The combination of the disrupted barrier and water-holding functions in nonlesional skin is closely linked to the disease severity of AD, which suggests that the barrier abnormality as well as the water deficiency are elicited as a result of the induced dermatitis and subsequently trigger the recurrence of dermatitis. These functional abnormalities of the SC are mainly attributable to significantly decreased levels of total ceramides and the altered ceramide profile in the SC. Clinical studies using a synthetic pseudo-ceramide (pCer) that can function as a natural ceramide have indicated the superior clinical efficacy of pCer and, more importantly, have shown that the ceramide deficiency rather than changes in the ceramide profile in the SC of AD patients plays a central role in the pathogenesis of AD. Clinical studies of infants with AD have shown that the barrier disruption due to the ceramide deficiency is not inherent and is essentially dependent on postinflammatory events in those infants. Consistently, the recovery of trans-epidermal water loss after tape-stripping occurs at a significantly slower rate only at 1 day post-tape-stripping in AD skin compared with healthy control (HC) skin. This resembles the recovery pattern observed in Niemann–Pick disease, which is caused by an acid sphingomyelinase (aSMase) deficiency. Further, comparison of ceramide levels in the SC between before and after tape-stripping revealed that whereas ceramide levels in HC skin are significantly upregulated at 4 days post-tape-stripping, their ceramide levels remain substantially unchanged at 4 days post-tape-stripping. Taken together, the sum of these findings strongly suggests that an impaired homeostasis of a ceramide-generating process may be associated with these abnormalities. We have discovered a novel enzyme, sphingomyelin (SM) deacylase, which cleaves the N-acyl linkage of SM and glucosylceramide (GCer). The activity of SM deacylase is significantly increased in AD lesional epidermis as well as in the involved and uninvolved SC of AD skin, but not in the skin of patients with contact dermatitis or chronic eczema, compared with HC skin. SM deacylase competes with aSMase and β-glucocerebrosidase (BGCase) to hydrolyze their common substrates, SM and GCer, to yield their lysoforms sphingosylphosphorylcholine (SPC) and glucosylsphingosine (GSP), respectively, instead of ceramide. Consistently, those reaction products (SPC and GSP) accumulate to a greater extent in the involved and uninvolved SC of AD skin compared with chronic eczema or contact dermatitis skin as well as HC skin. Successive chromatographies were used to purify SM deacylase to homogeneity with a single band of ≈43 kDa and with an enrichment of >14,000-fold. Analysis of a protein spot with SM deacylase activity separated by 2D-SDS-PAGE using MALDI-TOF MS/MS allowed its amino acid sequence to be determined and to identify it as the β-subunit of acid ceramidase (aCDase), an enzyme consisting of α- and β-subunits linked by amino-bonds and a single S-S bond. Western blotting of samples treated with 2-mercaptoethanol revealed that whereas recombinant human aCDase was recognized by antibodies to the α-subunit at ≈56 and ≈13 kDa and the β-subunit at ≈43 kDa, the purified SM deacylase was detectable only by the antibody to the β-subunit at ≈43 kDa. Breaking the S-S bond of recombinant human aCDase with dithiothreitol elicited the activity of SM deacylase with an apparent size of ≈40 kDa upon gel chromatography in contrast to aCDase activity with an apparent size of ≈50 kDa in untreated recombinant human aCDase. These results provide new insights into the essential role of SM deacylase as the β-subunit aCDase that causes the ceramide deficiency in AD skin.

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Ait Khaldoun, Ibrahim, Lynda Mitiche, Amar Sahmoune und Clàudia Fontàs. „An Efficient Polymer Inclusion Membrane-Based Device for Cd Monitoring in Seawater“. Membranes 8, Nr. 3 (10.08.2018): 61. http://dx.doi.org/10.3390/membranes8030061.

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A novel and simple device that includes a polymer inclusion membrane (PIM) has been prepared and tested for the first time to detect low concentration levels of cadmium in seawater. The ionic liquid trihexyl (tetradecyl) phosphonium chloride (THTDPCl) has been shown to be an effective extractant when incorporated in a PIM that uses cellulose triacetate (CTA) as a polymer. However, it has been reported that the use of a plasticizer is mandatory to ensure an effective transport, which uses both ultrapure water and a nitric acid solution as a stripping phase. A special device incorporating a PIM made of 50% CTA, 40% nitrophenyl octyl ether (as a plasticizer), and 10% THTDPCl, effectively allows the quantitative transport and preconcentration of 10 µg L−1 Cd from seawater samples to a stripping phase consisting of 0.5 M HNO3 solution. This study shows that the efficiency of the PIM system is not affected by high salinity nor the presence of large amounts of other ions, and can thus facilitate Cd monitoring in seawater samples.

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Chen, Li, Yan Ming Wang, Juan Liu und Xing Yao Wang. „A Novel Synthesis of Nanometer Spherical β-Ni(OH)₂ Cathode Materials with High Electrochemical Performances“. Advanced Materials Research 936 (Juni 2014): 491–95. http://dx.doi.org/10.4028/www.scientific.net/amr.936.491.

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A novel hydrothermal stripping technique synthesis route, in which the nickel-loaded organic phase of naphthenic acid was directly stripped by water at 140-240 °C for 2.0 h to recover nickel as hydroxide precipitates, has been firstly developed. The nickel hydroxide powders synthesized by this route was the spherical β-Ni(OH)2 and had a small particle size in the range of 20-100 nm shown by XRD and TEM test. The results of electrochemical performances show that the nanometer β-Ni(OH)2 cathode materials have much higher discharge specific capacity, excellent capacity retention and cycle performances.

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Navarro, R. R., K. Sumi und M. Matsumura. „Heavy metal sequestration properties of a new amine-type chelating adsorbent“. Water Science and Technology 38, Nr. 4-5 (01.08.1998): 195–201. http://dx.doi.org/10.2166/wst.1998.0619.

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The performance of poly(CGMAPEI), an amine-type chelating adsorbent synthesized by graft polymerization, was evaluated in a simulated waste stream containing Cu2+ and Co2+ heavy metal ions and NaNO3 salt. Comparisons of metal adsorption curves of this adsorbent with a previously synthesized cellulose-PEI and commercially available chitosan-polyamine and amberlite resins were made. The poly(CGMAPEI) exhibited the highest capacity in the absence of NaNO3. At high concentrations of NaNO3, the affinities of all the amine-type adsorbents were found to be enhanced quite tremendously. The chelating adsorbent with the highest amine content (CS-03) showed the highest improvement in capacity. This phenomenon was not observed with the ion-exchanger (amberlite IRC 50) studied. Sodium ions showed negligible affinity for poly(CGMAPEI). Competition between Na+ with Cu2+ for adsorption sites in the adsorbent was absent. Regeneration experiments revealed some reduction in Cu2+ affinity of poly(CGMAPEI) after acid treatment. Difficulty in stripping Co2+ from poly(CGMAPEI) even by strong acid was also observed.

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Honeychurch, Kevin. „Trace Voltammetric Determination of Lead at a Recycled Battery Carbon Rod Electrode“. Sensors 19, Nr. 4 (13.02.2019): 770. http://dx.doi.org/10.3390/s19040770.

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Carbon rod electrodes (CREs) were obtained from recycled zinc–carbon batteries and were used without further modification for the measurement of trace concentrations of lead (Pb). The electrochemical behavior of Pb at these electrodes in a variety of supporting electrolytes was investigated by cyclic voltammetry. The anodic peaks obtained on the reverse scans were indicative of Pb being deposited as a thin layer on the electrode surface. The greatest signal–to–noise ratios were obtained in organic acids compared to mineral acids, and acetic acid was selected as the supporting electrolyte for further studies. Conditions were optimized, and it was possible to determine trace concentrations of Pb by differential pulse anodic stripping voltammetry. A supporting electrolyte of 4% v/v acetic acid, with a deposition potential of −1.5 V (vs. SCE) and a deposition time of 1100 s, was found to be optimum. A linear range of 2.8 µg/L to 110 µg/L was obtained, with an associated detection limit (3σ) of 2.8 µg/L. A mean recovery of 95.6% (CV=3.9%) was obtained for a tap water sample fortified with 21.3 µg/L.

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Nguyen, Viet Nhan Hoa, Thi Hong Nguyen und Man Seung Lee. „Review on the Comparison of the Chemical Reactivity of Cyanex 272, Cyanex 301 and Cyanex 302 for Their Application to Metal Separation from Acid Media“. Metals 10, Nr. 8 (17.08.2020): 1105. http://dx.doi.org/10.3390/met10081105.

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Cyanex extractants, such as Cyanex 272, Cyanex 301, and Cyanex 302 have been commercialized and widely used in the extraction and separation of metal ions in hydrometallurgy. Since Cyanex 301 and Cyanex 302 are the derivatives of Cyanex 272, these extractants have similar functional groups. In order to understand the different extraction behaviors of these extractants, an understanding of the relationship between their structure and reactivity is important. We reviewed the physicochemical properties of these extractants, such as their solubility in water, polymerization degree, acidity strength, extraction performance of metal ions, and the interaction with diluent and other extractants on the basis of their chemical structure. Synthetic methods for these extractants were also introduced. This information is of great value in the synthesis of new kinds of extractants for the extraction of metals from a diverse medium. From the literature, the extraction and stripping characteristics of metals by Cyanex 272 and its derivatives from inorganic acids such as HCl, H2SO4, and HNO3 were also reviewed. The replacement of oxygen with sulfur in the functional groups (P = O to P = S group) has two opposing effects. One is to enhance their acidity and extractability due to an increase in the stability of metal complexes, and the other is to make the stripping of metals from the loaded Cyanex 301 difficult.

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Muñoz, Carolina, Manuel Zúñiga und Verónica Arancibia. „Stripping voltammetric determination of cadmium in sea water using a carbon paste electrode modified with alginic acid from brown algae“. Journal of the Brazilian Chemical Society 21, Nr. 9 (2010): 1688–91. http://dx.doi.org/10.1590/s0103-50532010000900013.

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Aualiitia, T. U., und W. F. Pickering. „Anodic stripping voltammetric study of the lability of Cd, Pb, Cu ions sorbed on humic acid particles“. Water Research 20, Nr. 11 (November 1986): 1397–406. http://dx.doi.org/10.1016/0043-1354(86)90138-7.

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49

Amare, Meareg, Samuel Abicho und Shimelis Admassie. „Determination of Fenitrothion in Water Using a Voltammetric Sensor Based on a Polymer-Modified Glassy Carbon Electrode“. Journal of AOAC INTERNATIONAL 97, Nr. 2 (01.03.2014): 580–85. http://dx.doi.org/10.5740/jaoacint.12-124.

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Abstract A glassy carbon electrode (GCE) modified with poly(4-amino-3-hydroxynaphthalene sulfonic acid) (poly-AHNSA) was used for the selective and sensitive determination of fenitrothion (FT) organophosphorus pesticide in water. The electrochemical behavior of FT at the bare GCE and the poly-AHNSA/GCE were compared using cyclic voltammetry. Enhanced peak current response and shift to a lower potential at the polymer-modified electrode indicated the electrocatalytic activity of the polymer film towards FT. Under optimized solution and method parameters, the adsorptive stripping square wave voltammetric reductive peak current of FT was linear to FT concentration in the range of 0.001 to 6.6 × 10–6 M, and the LOD obtained (3δ/m) was 7.95 × 10–10 M. Recoveries in the range 96–98% of spiked FT in tap water and reproducible results with RSD of 2.6% (n = 5) were obtained, indicating the potential applicability of the method for the determination of trace levels of FT in environmental samples.

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50

Makovskaya, O. Yu, A. P. Shevchuk und S. P. Sorokin. „Copper Recovery from Rinse Waters after Ammoniac Etching of Printed Circuit Boards“. Solid State Phenomena 299 (Januar 2020): 998–1004. http://dx.doi.org/10.4028/www.scientific.net/ssp.299.998.

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The process of sorption-electrochemical cleaning of rinse waters, obtained after ammonia etching of printed circuit boards from copper ions, is proposed. Cation exchanger KU-2×8 and ampholyte Lewatit MonoPlus TP 207 for the extraction of copper were tested. Capacity up to breakthrough of Lewatit MonoPlus TP 207 is 0.11 g/g and a full dynamic exchange capacity for copper of 0.15 g/g. Various options of a pregnant ion exchanger desorption are considered. The best stripping ability has a 20% solution of sulfuric acid. The possibility of desorption by a partially de-coppered eluate was studied. This scheme allows the use of acid formed in the process of copper electro-winning. The effect of concentrations of NH4Cl and NH4OH on the sorption of copper was studied. It was shown that, with an increase in the concentration of NH4Cl to 100 g/dm3, the capacity of the ion exchanger decreases by 10.42%. Thus, the ion exchanger Lewatit MonoPlus TP 207 effectively absorbs copper even at high salt background. A combined sorption-electrochemical technology has been proposed for treatment of rinse waters. The proposed technology will reduce consumption of fresh water and ammonia for printed circuit boards washing and extract copper in the form of elemental metal.

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