Diffusion dialysis-concept, principle and applications (original) (raw)
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The application of diffusion dialysis using various types of ion-exchange membranes for the separation of sulfuric acid and nickel sulfate has been evaluated. The process of dialysis separation of a real waste solution from an electroplating facility containing 252.3 g/L of sulfuric acid, 20.9 g/L of nickel ions and small amounts of zinc, iron, copper ions, etc. has been studied. Heterogeneous cation-exchange membrane containing sulfo groups and heterogeneous anion-exchange membranes with different thicknesses (from 145 μm to 550 μm) and types of fixed groups (4 samples with quaternary amino groups and 1 sample with secondary and tertiary amino groups) are used. The diffusion fluxes of sulfuric acid, nickel sulfate, and the total and osmotic fluxes of the solvent are determined. The use of a cation-exchange membrane does not allow separation of the components, since the fluxes of both components are low and comparable in magnitude. The use of anion-exchange membranes makes it possib...
Porous Anion Exchange Membrane for Effective Acid Recovery by Diffusion Dialysis
Processes, 2021
Diffusion dialysis (DD) employing anion exchange membranes (AEMs) presents an attractive opportunity for acid recovery from acidic wastewater. However, challenges exist to make highly acid permeable AEMs due to their low acid dialysis coefficient (Uacid). Here, a series of porous and highly acid permeable AEMs fabricated based on chloromethyl polyethersulfone (CMPES) porous membrane substrate with crosslinking and quaternization treatments is reported. Such porous AEMs show high Uacid because of the large free volume as well as the significantly reduced ion transport resistance relative to the dense AEMs. Compared with the commercial dense DF-120 AEM, our optimal porous AEM show simultaneous 466.7% higher Uacid and 75.7% higher acid/salt separation factor (Sacid/salt) when applied to acid recovery at the same condition. Further, considering the simple and efficient fabrication process as well as the low cost, our membranes show great prospects for practical acid recovery from indust...
Acidic Recovery from Wastewater of Automotive Battery Plant Using Membrane Technology
Applied Environmental Research, 2016
Diffusion dialysis (DD) equipped with anion exchange membranes (AEMs) is used as an effective tool to recover acid from various types of waste acid solutions. The aim of this study was to investigate the possibility of using the DD process to recover sulfuric acid (H s SO 4) from the acidic wastewater from an automotive battery plant. A numbers of experimental runs was conducted to optimize the equipment's operating conditions, particularly variations in feed flow and flow rate ratios. The results showed that H 2 SO 4 permeated well through the AEM, while metal ions were efficiently rejected. The recovery of H 2 SO 4 increased as flow rate decreased. Approximately 84.5 % of H 2 SO 4 could be recovered at 9 .38 × 10-5 m 3 h-1 m-2. Pb 2+ rejection was 69.5 %. In addition, recovery efficiency could be improved by increasing the flow rate ratio. At the highest flow rate ratio, DD could recover up to 90% of H 2 SO 4 while the lowest rejection of Pb 2+ (61 %) was obtained. Also, the investigation of the effect of variation of flow rate ratio on recovery efficiency revealed that the optimum flow rate ratio should be controlled at around 1 to 1.2.
Recycling of spent nitric acid solution from electrodialysis by diffusion dialysis
Desalination, 2011
Laboratory study of recovering HNO 3 solution from acidic effluents discharged by an electrodialysis plant for extracting lithium from concentrated brine at East Taijinar Salt Lake, China, was conducted using diffusion dialysis (DD) with homogenous anion exchange membrane (DF120). The effects of concentrations of nitric acid and metal ions (including Li, Na, K, Mg, Ca) and water to spent acid flow rate (W/A) ratio on the performance of diffusion dialysis were investigated. Results indicated that acid recovery increased with the concentration of the feed. The membrane showed moderate monovalent permselectivity: divalent cations were more effectively retained as opposed to monovalent cations. The selectivity between metal and hydrogen ions were impaired by increasing W/A ratio. The acid recovery reached its maximum at 3.0 mol/L H + , demonstrating that the efficiency at feeding concentrations above 3.0 mol/L would be low for the DF120 membrane. The increase of salt content in the spent acid to 3.0 mol/L and above conceivably impaired the selectivity of the membrane. As such, acid recovery should be best performed with acid effluents with lower-to-medium salt content and hydrogen concentration. Also, a suitably lower W/A ratio should be adopted for effective acid recovery with low water cost.
BPPO-Based Anion Exchange Membranes for Acid Recovery via Diffusion Dialysis
Materials, 2017
To reduce the environmental impact of acids present in various industrial wastes, improved and robust anion exchange membranes (AEMs) are highly desired. Moreover, they should exhibit high retention of salts, fast acid permeation and they should be able to operate with low energy input. In this work, AEMs are prepared using a facile solution-casting from brominated poly-(2,6-dimethyl-1,4-phenylene oxide) (BPPO) and increasing amounts of 2-phenylimidazole (PI). Neither quaternary ammonium salts, nor ionic liquids and silica-containing compounds are involved in the synthesis. The prepared membranes showed an ion exchange capacity of 1.1-1.8 mmol/g, a water uptake of 22%-47%, a linear expansion ratio of 1%-6% and a tensile strength of 0.83-10.20 MPa. These membranes have potential for recovering waste acid via diffusion dialysis, as the acid dialysis coefficient (U H) at room temperature for HCl is in the range of 0.006-0.018 m/h while the separation factor (S) is in the range of 16-28, which are higher than commercial DF-120B membranes (U H = 0.004 m/h, S = 24).
Performance of Diffusion Dialysis for Pickling Effluent Operating Under a High Flow Rate
2016
Diffusion dialysis (DD) is a membrane separation process. The major driving mechanism is an ionic concentration gradient. An anion-exchange membrane (AEM) equipped with DD is efficiently used for purifying waste acid and metal ion separation. The goal of this laboratory-scale study is to investigate the efficiency of a diffusion dialyser (model HKY-001), which was equipped with an AEM (model DF120), to purify waste acid solution (sulphuric acid). This study was conducted with actual waste acid from a pickling bath of an electroplating manufacturer in Samut Prakarn Province. In the experimental tests, the operating parameters, such as time to reach equilibrium, feed flowrate, water to feed (Q water /Q feed ) and type of stripping water, were varied. To examine the performance of this treatment unit, the concentration of H + (mol.L -1 ), acid recovery (% as H + ) and metal ion rejection (%) were monitored regularly. In conclusion, increasing the feed flow rate will likely decrease the...
Design of a novel membrane-integrated waste acid recovery process from pickling solution
Journal of Cleaner Production, 2019
Hydrochloric acid pickling is a common practice in steel manufacturing industry. During the process, acid is consumed to dissolve surface oxides and metals ions are accumulated in the solution, which becomes less effective with time. In addition, the costly and risky waste acid disposal is another issue affecting the hot-dip galvanizing industry. In this work, a novel sustainable waste acid recovery process from pickling solutions based on circular approach is proposed to tackle these issues. The innovative system allows (i) the continuous regeneration of pickling solutions to enhance process rate and performance and (ii) minimise the highly expensive and environmentally risky wastewater disposal. In this way, refilling pickling baths with fresh acid, as done in conventional operation, can be avoided and can be carried out continuously under optimal working conditions. Moreover, the recovery of valuable substances (e.g. metal hydroxide or salts solution) can be obtained as an additional benefit. Continuous treatment and regeneration of pickling solution can be accomplished by coupling diffusion dialysis (DD) and
Canadian Journal of Chemical Engineering, 1994
In this work some mixtures of sulphuric and nitric acids have been separated and concentrated by selective electro-dialysis (SED) using heterogeneous membranes. Selective membranes can now be used for the separation of acids since anion exchange membranes with reduced transport number to multivalent ions are commercially available. The electric performance of the system has been analyzed and a correlation between current density, hydrodynamic parameters and concentration was established. The modelling of the SED experiments can be achieved with a good fitting for various membrane configurations of industrial interest.Experimental results show that at operation times lower than 40 minutes, the selective anion exchange membranes efficiently exclude the sulphate anions. The nitrate anions fall to zero concentration at 60 minutes of operation and then the sulphate anions begin to cross through the membrane.On a untilisé une technique d'électrodialyse sélective (SED) avec des membranes héterogènes pour la séparation de plusieurs mélanges d'acides nitrique et sulphurique. Des membranes sélectives aux anions sont actuellement disponibles avec des valeurs réduites des nombres de transport aux ions multivalents. On a étudié le rendement electrique du systéme et établie une corrélation en fonction de la densité de courant, des conditions hydrodynamiques et de la concentration des solutions utilisées. La modélisation des expériences d'électrodialyse sélective peut être réalissé en obtenant des résultats semblables aux expérimentaux pour plusieurs configurations des membranes ayant un intérêt industriel.Les résultats expérimentaux montrent que pour des temps d'opération inférieures à 40 minutes les anions sulphate sont exclus par la membrane avec une bonne efficacité. Lorsque la durée des expériences atteint 60 minutes la concentration des anions nitrate descend jusqu'à zero et alors les anions sulphate commencent à être transférés à travers la membrane.