Papers by Keyword: Liquid Membrane

Abstract: The extraction of copper (II) ions using di (2-ethylhexyl) phosphoric acid – based liquid membranes during a galvanostatic electrodialysis-electrolysis process was studied. Effects of the current density, copper (II) and hydrochloric acid concentration in the feed solution, carrier and admixture concentration in the liquid membrane, type of acid in the catholyte were studied, and the optimal conditions were determined. A practically complete removal of copper (II) from the feed solution containing 0.01 M CuCl₂ was achieved during 3.0 −4.0 h of electrodialysis. A possibility of effective transfer and electrodeposition of copper (II) from dilute solutions of sulfuric, hydrochloric, perchloric, nitric and acetic acids was shown. Adherent copper coatings with a fine-grained structure were obtained from dilute sulfuric acid solutions. A maximum stripping degree into the catholyte of 88 % and an electrodeposition degree of 73 % were achieved in the studied system.

Abstract: The processes of Zn²⁺ and Pb²⁺ extraction by bulk liquid membranes containing di (2-ethylhexyl) phosphoric acid and tri-n-octylamine during galvanostatic electrodialysis accompanied by electrodeposition of the metals were studied. The effects of the current density as well as of composition of the liquid membranes and aqueous solutions on the rate of zinc (II) and lead (II) transport were determined. It was demonstrated that a practically complete removal of zinc (II) and more than 90 % extraction of lead (II) from the feed solutions containing 0.01 M ZnSO₄ or 0.01 M Pb (NO₃)₂ was achieved during 1.0 − 5.0 h of electrodialysis. A possibility of effective transfer of zinc (II) into dilute solutions of sulphuric, hydrochloric, perchloric and acetic acids was shown. Adherent zinc and lead coatings with a fine-grained structure have been deposited on the platinum cathode. More than 75% of zinc (II) and about 60% of lead (II) was deposited from solutions of sulfuric acid and perchloric acid, respectively.

Abstract: A novel method for Co (II) and Pb (II) recovery from acidic solutions is presented. The extraction of Co (II) and Pb (II) ions using the bulk liquid membranes during a galvanostatic electrodialysis process accompanied by cathodic electrodeposition of the metals was studied. Solutions of di (2-ethylhexyl) phosphoric acid (D2EHPA) with admixtures of tri-n-octylamine (TOA) in 1,2-dichloroethane were used as the liquid membranes. Effects of current density, Co (II) and Pb (II) concentrations in the feed solution, sulfuric or nitric acid concentration in the feed solution, D2EHPA and TOA concentration in the liquid membrane, of the type and concentration of acid in the cathodic solution were studied, and optimal conditions were determined. It is demonstrated that a practically complete (98-99%) removal of Co (II) and Pb (II) from the feed solutions containing 0.01 mol∙L^-1 CoSO₄ or 0.01 mol∙L^-1 Pb (NO₃)₂ is achieved during 1.0 − 4.0 h of electrodialysis. A possibility of effective transfer of Pb (II) into dilute solutions of perchloric and nitric acids was demonstrated. The liquid membranes ensure the recovery of Co (II) ions into dilute solutions of perchloric, sulphuric, hydrochloric and nitric acids. Adherent, compact cobalt and lead electrodeposits with a fine-grained structure were obtained in the studied systems.

Abstract: Hippuric acid as an important raw material used to synthesize medication and coloring matter, abound in urine of much animal, especially in cattle. Hippuric acid usually is letted into river and soil with the urine. But as its chemical stability, hippuric acid couldn’t be decomposed easily and pollute the environment. This research finds effectively liquid membrane to treat with such waste water such as breeding wastewater that contains high hippuric acid. In our study, the best liquid membrane was found by searching what and how much surface active agents and carrier are suitable, pH of out-water of the liquid membrane and concentration of NaOH in the in-water of liquid membrane. As the outcome shown, the best prescription is surface active agent T-151(2% mass fraction), liquid carrier TBP( 4% mass fraction), pH of out-water 2.0, concentration of NaOH in the in-water 0.50mol/L. Under the condition, extraction rate of hippuric acid from breeding wastewater can reach more than 98% during 9min.

Abstract: The transportation and separation of Cu(Ⅱ) through a dispersion supported liquid membrane(DSLM) consisting of 2-ethylhexyl Phosphonic Mono-(2-Ethylhexyl) in kerosene, supported on the polyvinylidene fluoride membrane(PVDF), is studied. The effects of pH value in the feed phase, volume ratio of liquid membrane phase and hydrochloric acid, concentrations of HCl in the strip phase and initial concentration of Cu(Ⅱ) in the feed phase are also researched. The results show that copper ion can be transported effectively when pH =5.25 in the feed phase, the volume ratio is160:40, concentrations of HCl in the strip phase is 4.0mol/L. Under the optimum transport conditions, when initial concentration of Cu(Ⅱ) was 2.00×10^-4mol/L, the transport rate of Cu(Ⅱ)was up to 94.7% in 130 min.

Abstract: The method of wettability of solid-liquid interface is used to examine the differences of the liquid membranes formed by hydrophilic or hydrophobic membranes with different size and different materials, the influence of the characteristics of membrane modules in the process of desulfurization is studied. The method of accelerating the renewing rate of liquid membrane is proposed. The results show that the hydrophobic liquid membrane leads to higher renewing rate and absorption efficiency of sulfur dioxide and the hollow fiber membrane of polypropylene has higher adsorption efficiency. The dynamic contact angle of the same hollow fiber membrane is increasing with the number of the fibers leading to the increase of the diffusing resistance of liquid between the fibers. In order to accelerate the renewing rate of the liquid membrane, the concentration of the medium should be decreased under the condition of high absorption capacity.