Galvanic Wastewater Treatment by Means of Anionic Polymer Enhanced Ultrafiltration

Abstract

This work is focused on polyelectrolyte enhanced ultrafiltration as an effective heavy metal separation technique. Three types of effluents, containing Zn(II), Cu(II) and Ni(II) ions, were subjected to the separation process. Poly(sodium 4-styrenesulfonate) -PSSS, a water soluble anionic polyelectrolyte was used as a metal binding agent. Two Sepa® CF (Osmonics) membranes: EW, made of polysulfone and a modified polyacrylonitrile membrane MW, were used in the ultrafiltration process. The preliminary UF tests were carried out on model solutions with target metal ion concentrations of 10, 100 and 250 mg dm . The main parameters affecting the metal retention (the polyelectrolyte quantity and solution pH) were examined. The values of pH 6 and polymer : metal concentration ratio CPSSS : CM = 7.5 : 1 (mol of mer unit per mol of metal) were selected to perform the galvanic wastewater ultrafiltration-concentration tests. Three types of wastewater containing Zn(II), Ni(II) and Cu(II) ions within the concentration range of 30÷70 mg dm -3 were used in the investigations. Very high metal retention coefficients, up to > 99%, were achieved. The retentates obtained were subjected to the decomplexation-ultrafiltration (pH = 1) and subsequent diafiltration step, which enabled partial recovery of concentrated metal ions and the polyelectrolyte. The recovered polyelectrolyte was reused toward Ni(II) ions and the high effectiveness of metal separation has been achieved. Keywords: polymer enhanced ultrafiltration, heavy metals, galvanic wastewater, polyelectrolyteThe membrane separation processes create new possibilities for the effective purification of galvanic wastewater. One of the most interesting propositions is a polymer enhanced ultrafiltration which combines two processes: metal ions binding with soluble polymeric ligands and retention of resulting macromolecular compounds on an ultrafiltration membrane. Polymer enhanced ultrafiltration has been successfully applied to the separation of metal ions from aqueous solutions, most often Cu, Ni, Zn, Co, Cd, Hg, Cr(III) and radionuclides [1][2][3][4][5][6][7].Basically, two types of polymer used in the process can be distinguished. The first one encompasses chelating polymers, able to form coordination bonds with metal ions, the other includes polyelectrolytes, which have ion-exchange properties. Typical polymers that bind

Use of sodium alginate biopolymer as an extracting agent of methylene blue in the polymer‐enhanced ultrafiltration technique

“…28,29 Pollutant species that have limited or no interaction with the polymer are eluted to the filtrate. 30,31 It has been reported in the literature that this technique has been used for the removal of various metal ions from water, along with emerging contaminants and cationic dyes. 16,[32][33][34][35] In a previous study, the removal of chromium (III) and (VI) from water using PEUF was investigated.…”

“…In addition, it is important to consider the characteristics of WSP with respect to variations in the charge relationships (positive and negative) in its structural chain, which can be of natural or synthetic origin at various pH values. 27,30,38,39 Polymers of natural origin have aroused substantial interest in recent years due to their low cost, high availability, biodegradability and biocompatibility for use in various applications. [40][41][42] Alginate is a biopolymer that is derived from seaweed.…”

Combined Wastewater Treatment from Manganese Phosphate Coating: Coagulation-Ozonation-Fenton Reaction-Sorption

“…The methods of industrial wastewater treatment include precipitation techniques with the use of calcium compounds [7,8], coagulation methods with the use of aluminum and iron compounds [9,10], treatment with the use of membrane methods [11], adsorption processes using zeolites or biomass [12], processes using nanofiltration or reverse osmosis [13,14], electrodialysis [15][16][17], photocatalytic methods [18], ultrafiltration [19], purification with the use of activated carbon [20][21][22] as well as techniques of advanced oxidation with the use of ozone, hydrogen peroxide, UV radiation and Fenton's reagents [23,24]. Beside chemical methods, we should also list physical methods in wastewater treatment, such as sedimentation [25] or processes related to the equalization of wastewater flow, which mainly consist of buffering by introducing equalizing devices or such retaining the flowing wastewater [26].…”

Characteristics of Polymeric Ultrafiltration Membranes Produced with the Use of Graphene Oxide

“…Nowadays wastewater coming from various industries is a growing problem for the environment [1]. Many methods are used to purify them, but membrane techniques, often enriched with natural and synthetic nanoparticles, are becoming more and more popular [2,3].…”