Separation of Cd(II) from aqueous solutions by a new consecutive process consisting of supported liquid membrane and electrodialysis

Supported liquid membrane process usually is used for recovering or enrichment of valuable metals in the industrial wastewater. But, even if the metals in the wastewater was separated with high chemical selectivity, it cannot be enough concentrated since separation performance of supported liquid membrane (SLM) process is limited by concentration gradient between feed solution and stripping solution. If metal concentration in the stripping solution to be enough low, transport of metal through membrane can be accomplishment constantly. Therefore, Electrodialysis (ED) has been placed after SLM process and the stripping solution of SLM was used as the feed solution for the ED process. Transport of ions in the solutions is successfully performed by ED process. Thus, the metal concentration in the stripping solution does not rise as to stop ion transport. Besides, valuable metals easily are concentrated by ED process for re-use. In this study, effects of operation parameters like initial Cd(II) concentration, HCl concentration in the feed solution of SLM and applied voltage are investigated on separation efficiency, flux and permeability of the both processes. As the feed solution concentration increased, all performance values has increased. When initial concentration of 100 mg/L is used, separation performances (SP) are 55% and 70%, for SLM and consecutive process, respectively. The best HCl concentration in the feed solution of SLM has determined as 2 M, in this conditions SP are 64% and 72%, for SLM and consecutive process, respectively. With increased of applied voltage on ED process, SP of the consecutive process has been raised from 72% to 83%. According to the obtained experimental data, consecutive process has better separation performance than SLM. When the separation performances of both processes were compared for the same operating conditions, it was determined higher the separation efficiency, permeability and flux values of the consecutive process, 8%, 9% and %10.6, respectively. Consequently, the use of the consecutive process increases the performance efficiency of both processes. The consecutive process studied has quite a good chemical separation efficiency, and enrichment capability. Moreover, this process requires few water and energy. © 2019, Korean Electrochemical Society. All rights reserved.2014-77047330-07This research was financially supported by the Research Fund of Bulent Ecevit University (Project code: 2014-77047330-07)

Removal of Remazol Turquoise Blue (G-133) and Polyvinyl Alcohol (PVA) by Electrocoagulation using Monopolar and Bipolar Electrodes

WOS: 000290115000004This study aims to investigate color and COD removal efficiencies of electrocoagulation (EC) process for dye solutions simulated by using polyvinyl alcohol (PVA) and reactive dyestuff of Remazol Turquoise Blue (G-133). The two different electrode configurations, namely monopolar and bipolar, were examined to find out the better alternative intensifying the performance of the process. The results obtained from these tests show that an EC cell with bipolar electrodes has produced slightly higher color and COD removal efficiencies than that of an EC cell with monopolar electrodes. The best removal efficiencies have been found for the both electrode configurations under the conditions that the time of electrolysis is 30 min, the constant direct current (DC) value 0.75 A and the initial pH value 3. Consequently, the bipolar electrode configuration (BPEC) has yielded 72.7 percent COD and 99.8 percent color removals while the monopolar electrode configuration (MPEC) producing 65.2 percent COD and 99.6 percent color removals

Comparison of electrodialysis and reverse electrodialysis processes in the removal of Cu(II) from dilute solutions

Electrodialysis (ED) and electrodialysis reversal (EDR) processes have been often used for separation of ions in dilute solutions. In this study, the performance of ED and EDR processes has been examined in the removal of copper from the dilute solutions. First, applied voltage, initial concentration, flow rate, type of electrolyte and the effect of concentration were determined for both processes. Then, separation efficiency, current efficiency, energy requirement and material flux of the processes were calculated, and the performances of the processes were compared. The separation efficiency and energy consumption of EDR process were higher compared to ED process under equal operating conditions. Also, the current efficiency (39.58%) of EDR process was lower than the current efficiency (67.46%) of ED process. It can be said that the ED process is more suitable in terms of energy consumption for separation in the low flow rate and concentration. © 2017, Korean Institute of Chemical Engineers, Seoul, Korea

Treatment of kraft pulp and paper mill wastewater by electro-fenton/electro-coagulation process

The present study aims to examine the electro-Fenton/electro-coagulation (EF/EC) process for the treatment of wastewater generated from Kraft pulp and paper mills. As a result of the experimental studies, the optimum operating parameters of the EF/EC process have been identified as follows: current = 1.0 A, initial H2O2 concentration = 1000 mg/l and initial pH 2.5. It has been established that, under these conditions, the COD could be removed at 91.7%. It has been understood that the sludge produced from the EF/EC reactor possesses fairly good sedimentation characteristics and is significantly affected by the operating parameters. It has been established that the best sedimentation characteristics can be achieved when the current is ? 1.0 A, the initial pH value is between 2.3 and 3.2, and the initial H2O2 concentration is between 400 and 1800 mg/l

Transport of silver ions through a flat-sheet supported liquid membrane

WOS: 000279306100022Toxic metals from industrial wastewaters are an important environmental issue. The use of supported liquid membrane processes has gained momentum in recent years, as it allows the reuse of water and toxic metals. The aim of this study is to investigate the active transport of silver ion through a supported liquid membrane (micro-porous Fluoropore PTFE) of DC18C6 (Dicyclohexano18crown6) in toluene under various experimental conditions. For this purpose, the effects of various parameters including binary carriers, carrier concentration, feed phase concentration, the nature and concentration of stripping agents in the stripping phase and flow rates of feed and stripping phases on transport efficiency were also investigated. The maximum transport efficiency was observed at the following conditions: flow rates of 50 mL/min in both phases, 0.05 M DC18C6 in toluene as carrier solution. 50 ppm Ag(+) dissolved in 0.015 M HNO(3) as feed solution and 0.08 M Na(2)S(2)O(3) as stripping solution Optimum operation time was determined as 240 min. Under these conditions, 94% of the silver ions were transported from the feed phase to the membrane phase. However, the transport rate from the membrane phase to the stripping phase remained at approximately 81%. (C) 2010 Elsevier B.V. All rights reserved.Scientific and Technological Research Council of Turkey (TUBITAK)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [106Y085]This study was supported by The Scientific and Technological Research Council of Turkey (TUBITAK) as a research project (project no.: 106Y085)

INFLUENCE OF FLOW RATE ON THE REMOVAL OF COPPER, LEAD AND NICKEL FROM SOLUTIONS IN ELECTRODIALYSIS PROCESS

In electrodialysis (ED) of heavy metals such as copper, lead and nickel from solutions, one of the main operating parameter is the flow rate. The study focus on understanding the impact of different flow rates on removal efficiency, current efficiency, specific electrical energy consumption and removed amount of matter in mg. 70, 140 and 200 mL/min of flow rates has been applied to ED stack which has constant operating parameters of 0.05 M NaCl containing electrolyte solutions, 45 V of applied voltage, pH of 6 and dilute solutions with heavy metal concentrations of 2 mg/L. After 360 min. of ED process removal efficiencies of all types of metals has shown an increment trend. As an opposite effect, current efficiencies has been declined. When examining the removed amount of matter during process, parallel indications to removal efficiencies has been determined. Increasing flow rates has increased the amount of matter removed. Last findings on the removal of heavy metal depending on flow rates were specific electrical energy consumptions. Comparing flow rates of 70 and 200 mL/min, energy consumptions per mg of heavy metal removed has raised. These results clearly points out that flow rate of dilute and electrolyte solutions in EC has an alternating effect on process. Further researches can be done for improving the removal efficiency and lowering the electrical energy consumption depending on other operational parameters on electrodialysis

Effect of carrier-solvent combination and stripping solutions on zinc transport by supported liquid membrane

This study analyzed the zinc transport in supported liquid membrane (SLM) systems in which different anionic (Aliquat336) and cationic (D2EHPA) carriers, different solvents (kerosene and toluene) and different feed (deionized water and HCl) / stripping solutions (H3PO4, HCl and H 2SO4) were used. The results were modeled according to steady state (Fick's first law) and non-steady state kinetics approaches and the concordance of the models was discussed. It was observed from the experimental studies that 80.4% zinc transport could be achieved when deionized water was used as feed solution, kerosene/ D2EHPA (0.01 M) as membrane solution combination and H3PO4(0.5 M) as stripping solution. Whilst the zinc transport efficiency was found to be 86.5% when HCl (1.0 M) was used as feed solution, toluene-Aliquat336 (0.02 M) as membrane solution combination and HCl (0.5 M) as stripping solution. Modeling studies established that the nonsteady state approach better represented zinc transport. It was therefore concluded that the zinc transport mechanism was affected by interface reactions rather than diffusion. © by PSP

Environmental knowledge of primary school students: Zonguldak (Turkey) example

4th World Conference on Learning, Teaching and Educational Leadership (WCLTA) -- OCT 27-29, 2013 -- Univ Barcelona, Barcelona, SPAINWOS: 000345351800186The number of environmentally conscious individuals in society can be raised by increasing environmental education quality in primary schools. Starting studies about environment in the childhood years is very important. In this study, the knowledge and skill levels of primary school students in Zonguldak about waste recycling was determined, and the participation levels of theirs into recycling activities was measured. For this aim, the third and fourth grade primary school students were identified as a target group of the study, and a questionnaire assessing the impact of the parents' socio-economic structures and education status on environmental awareness of theirs was prepared. The results were evaluated to determine the strengths and weaknesses of environmental education of the students, statistically. The questionnaire was conducted in three elementary schools having different social and economic levels. Questions in the first, second and last parts of the questionnaire relate with the demographic characteristics of students families, the environmental awareness of the students, and the participation of students into recycling activities, respectively. The survey reviews were carried out with a statistical program and differences between the schools were determined by using one way ANOVA test. (C) 2014 The Authors. Published by Elsevier Ltd

Facilitated transport of Cd(II) through a supported liquid membrane with Aliquat 336 as a carrier

Selective removal of cadmium from wastewaters is very important, because cadmium is toxic for the environment and for human health. This work is a comprehensive study on the selective removal of Cd(II) from aqueous solutions by using a co-current flow flat sheet supported liquid membrane system. 4.4 × 10-4M Cd(II) concentration was used as a feed solution in the experiments. Toluene containing Aliquat 336 was used as the membrane liquid in the membrane system. Parameters such as the properties of feed and stripping solutions, carrier concentration, and flow rate, which have roles in transport of Cd(II) ions, were optimized. The efficiency of the system is expressed in terms of permeability and flux values, and transport efficiency. The optimum process conditions for the Cd(II) transport are experimentally found as follows: The feed solution as 2 M HCl, the carrier concentration as 0.1 M Aliquat 336, the stripping solution as 0.06 M EDTA, and the flow rates for the feed and stripping solutions as 50 mL/min and 80 mL/min, respectively. Under these conditions, the Cd(II) transport efficiency is found to be 82%. © Taylor & Francis Group, LLC.106Y085This study was supported by the Scientific and Technological Research Council of Turkey (TÜBİTAK) as a research project (Project No: 106Y085)

Effects of acceptor phase and donor phase properties on sodium ions transport from aqueous solutions using liquid membrane systems

In this study, the effects of the acceptor phase and the donor phase properties on sodium ion transport were examined in bulk liquid membrane systems. In the experiments, toluene and a mixture of toluene-dichloromethane (90-10%, v/v) containing 1 × 10-3 M DB18C6 (dibenzo18crown6) was used as the membrane. In order to examine the effects of different the acceptor phases, firstly H2SO4, HCl, HNO3, CH3COOH and distilled water were used as the acceptor phases. Furthermore, the experiments were performed by using various acid concentrations such as 2, 0.2 and 0.02 M of acids, as the acceptor phase. In the second part of the study, the effect of donor phase on sodium ion transport was examined. For this examination, Na2SO4, NaNO3, NaOH and NaCl were applied. In order to determine the effect of the donor phase concentration, the experimentation was performed using 1.08 × 10-2, 2.17 × 10-2, 3.26 × 10-2 and 4.34 × 10-2 M concentrations of Na+ in form of NaCl. Finally, nonsteady-state kinetics was applied on all data obtained from the experiments and reaction constants (k1, k2, and k3) and the values of the Rmax, tmax, k1/k2 were calculated. Consequently, it was determined that the type and the concentration of the acceptor phase and the donor phase solutions were significant for transport efficiency in liquid membrane systems. The most efficient transport was obtained by applying 2 M H2SO4 and 2.17 × 10-2 M Na+ in form of NaCl. Besides, It was observed that there was a significant effect of the anion attached to the cation on transport efficiency. © 2007 Elsevier B.V. All rights reserved.Cumhuriyet Üniversitesi: M-183This study was supported by Research Fund of Cumhuriyet University, Turkey (Project code: M-183)