Polymer assisted ultrafiltration for copper?citric acid chelate removal from wash solutions of contaminated soil (original) (raw)
Related papers
Desalination, 2004
Some results on metal ions removal from wastewaters using water-soluble polymers such as polyethylenimine (PEI), polyacrylic acid (PAA), polyacrylic acid sodium salt (PAASS) and poly(dimethylamine-co-epichlorohydrin-coethylene-diamine) (PDEHED) as chelating agents and the Cu 2+ ion as the model in combination with a polymer-assisted ultrafiltration process (PAUF) are reported. In particular, the performances of these polymers in Cu 2+ removal from wastewaters were compared. Tests of bonding capacity and best operating conditions of the process showed that complexation conditions depend on pH; indeed, copper ions are complexed by PEI, PAA, PAASS and PDEHED at pHs higher than 6, 4.6, 4.6 and 8, respectively. The decomplexation reactions took place at pH <3. Bonding capacity was 0.333 mg Cu 2+ /mg polymer, meaning a ratio of polymer/Cu 2+ = 3 (w/w) for PEI, PAA and PAASS. For the chelating agent PDEHED, a ratio of PDEHED/Cu 2+ = 0.5 (w/w) was determined. UF tests, realized at two transmembrane pressures (2 and 4 bar) by using five different flat-sheet membranes, showed that the PAA polymer and the PAN GKSS HV2/T membrane can be used when the objective of the purification process is to decrease metal concentration not lower than a certain value. The PDEHED polymer is useful if the objective of wastewater treatment is to obtain complete copper removal. Simple washings with tap water were enough for regeneration and reuse of the membranes.
Removal of heavy metal ions by polymer enhanced ultrafiltration
Desalination, 2012
A batch process of polymer enhanced ultrafiltration (PEUF) for the removal of Cu(II) ions from aqueous effluents has been developed in an installation equipped with mineral membranes at laboratory scale. It has been proposed a model based on mass conservation equations and kinetics of complex formation reactions of macromolecular species comprising a metallic ion and a water-soluble polymer. The model predicts the temporal evolutions of metal concentration in permeate and rejected streams. Moreover, it enables to establish the operating pH values to tackle the stages of metal retention and polymer regeneration, and also to calculate conditional formation constants of the macromolecular complex as a function of pH and temperature.
Polymer binding/ultrafiltration as a method for concentration and separation of metals
Journal of Membrane Science, 1993
A hybrid method for the separation and concentration of metals was investigated. The method includes binding of target metal ions by a polyelectrolyte into water soluble macromolecular compounds and subsequent membrane separation of the bound metals from unbound components. The influence of the composition and pH of the solution on the effectiveness of the separation process was studied. A mathematical model of this process was developed. The competitive character of interaction of metals with a polymer, metal ion hydrolysis and other phenomena were taken into account in the model. Optimum process conditions were determined and applied to the solution of particular problems such as the recovery of valuable metals from sea water and treatment of industrial wastes.
Cadmium removal from aqueous solutions by polyelectrolyte enhanced ultrafiltration
Desalination, 2009
Enhanced ultrafiltration by the addition of poly(ammonium acrylate), with two average molecular weight 8000 Da and 15 000 Da, for the removal of Cd(II) from aqueous solutions has been studied. The solution is processed by ultrafiltration using a membrane with pore sizes (10 kDa) small enough to block the passage of the polymer and adsorbed metal ions. Suitable experimental conditions (e.g. pH, polymer and metal concentration, and polymer molecular weight) for cadmium recovery and permeate flux have been optimised. Cadmium rejection coefficient increases with monomer concentration and reaches 99% values at twofold cadmium concentrations. As a consequence, two monomers units (C 2 H 3 COO-) are necessary to coordinate 1 ion mol of cadmium. Based on this experimental result, a simple mathematical model that allows calculating the apparent polymer-metal complex (PMC) formation constant has been established. The influence of pH has been studied to fix the pH for metal retention and polymer regeneration experiments.
Removal and enrichment of copper ions from aqueous solution by 1,8-diaminonapthalene polymer
European Polymer Journal, 2008
Heavy metal ions pH effect a b s t r a c t Microparticles of poly(1,8-diaminonapthalene) (PDAN) were prepared by chemically oxidative polymerization by (NH 4 ) 2 S 2 O 8 . The effect of pH on the sorption of Cd(II), Cu(II), Ni(II), Mn(II), Zn(II) and Pb(II) on PDAN was examined by the batch procedure. PDAN showed good sorption capacity and high selectivity towards Cu(II) in comparison with the very popular chelating sorbent Chelex 100 containing iminodiacetic functional groups.
DESALINATION AND WATER TREATMENT, 2021
Polymer-enhanced ultrafiltration was used to separate heavy metal ions from their multicomponent mixtures. Model solutions containing an equimolar mixture of Cu(II), Zn(II), Cd(II), Ni(II), Cr(III) were supplemented with poly(sodium acrylate) PSA (a metal-binding polymer) and the ultrafiltration process was carried out. The separation effectiveness of individual metal ions was studied under various process conditions (amount of PSA, pH, total metal concentration, presence of coexisting ions), and the possibility of simultaneous or selective (competitive) separation of individual ions from a multicomponent mixture was evaluated. Effective simultaneous separation of metal ions occurred in solutions containing a sufficient polymer dosage (polymer/metal molar ratio C PSA /C M ≥ 7) and at a sufficiently high pH (pH ≥ 6). Since the polymer showed differential affinity for the metals tested (Cr(III) ≈ Cu(II) > Cd(II) >> Zn(II) > Ni(II)), partially selective separation of ions from the mixture at a decreased pH or lowered C PSA /C M was possible. In addition, certain co-occurring ions (especially versenate, EDTA) decreased the separation effectiveness of Cu(II), Zn(II), Cd(II) and Ni(II). These preliminary observations were confirmed by the ultrafiltration concentration of the metal mixture, carried out at different values of the process parameters, and the subsequent decomplexation-ultrafiltration process (pH = 2), enabling the recovery of concentrated metal solutions of varying composition, depending on the process conditions.
Desalination, 2002
A process for recovery heavy metals-Cu(II), Ni(II), Pb(I1) and Cd(I1)-from industrial wastewaters has been studied. This process is called PSU (Polymer Supported Ultrafiltration), and includes complexation of metallic ions with polymers (polyethyleneimine-PEI, or poly(acrylic) acid-PAA), in order to make this solution flow through an ultrafiltration ceramic membrane and to obtain two different streams: permeate (nearly free of metal) and retentate (with high complex concentration). In a previous stage, complex stoichiometries and stabilities have been exhaustively studied by UV/visible absorbance spectrophotometry and potentiometric measures. Next, optimum operating conditions and best pH values affecting to permeate flux, complex formation, further polymer regeneration and polymer capacities have been achieved by means of ultrafiltration experiments. Flux and concentration values measured with these processes have been modeled with concentration polarization model, and mass transfer coefficients (k) and polarization concentrations (c,,,) have been obtained for different operation conditions. These data are not commonly reported in previous literature, although they are important for scale-up to an industrial process.
Desalination, 2005
A batch Polyelectrolyte Enhanced Ultrafiltration (PEUF) process with Poly(acrylic acid) sodium salt (PAA-SS) for the recovery of Cu(II) from industrial wastewaters has been studied. In contrast to previous researches, insertion of an internal steel rod inside tubular ceramic membrane, which implies a decrease of hydraulic diameter, enables to minimize pumping energy (lower feed flow rates are required) and provides high tangential velocities in order to avoid concentration polarization and to lessen fouling. Simultaneously, working at higher temperature improves turbulence conditions over the membrane and makes possible to increase operating polyelectrolyte concentration (maintaining high permeate fluxes) and, subsequently, metal ion concentration in waste stream to treat. Temporal decrease of permeate fluxes has been reproduced with an in-series resistance model. Evolution of metal rejection coefficients is estimated with a model taking into account chemical equilibriums in solution and mass conservation equations. Furthermore, replacement of a polyelectrolyte of analytical grade by an analogous polymer of industrial grade reduces significantly raw material costs.