EFFICIENT REMOVAL OF Cr(VI) BY POLYELECTROLYTE-ASSISTED ULTRAFILTRATION AND SUBSEQUENT ELECTROCHEMICAL REDUCTION TO Cr(III)

Abstract

This work is focused on the removal of Cr(VI) ions from aqueous solution using water-soluble poly(diallyldimethylammonium chloride), PDDA, coupled to an ultrafiltration membrane of regenerated cellulose and subsequent electrochemical reduction of Cr(VI) to Cr(III). The removal of Cr(VI), using the washing mode, was studied as a function of pH, the molar ratio of polymer:Cr(VI), and the presence of interfering ions. The enrichment mode was used to determine the maximum retention capacity of the polymer, and the release of Cr(VI) and regeneration of the polymer were analysed by sorption-desorption process. Subsequently, the electroanalysis of Cr(VI) was conducted by linear sweep voltammetry and full electrolysis at controlled-potential in acidic media and in the presence of PDDA.The results show an efficient removal of Cr(VI) (95%, 30 mg/L in the feed) using PDDA at pH 9 and a polymer:Cr molar ratio of 20:1. The retention capacity of the polymer was decreased by the presence of sulphate anions.The maximum retention capacity of PDDA was 33 mg Cr/g polymer at pH 9. Using the sorption-desorption process, the results indicated that this watersoluble polymer can release Cr(VI) and be regenerated. Finally, the electrolysis of Cr(VI) to Cr(III) was performed successfully in the presence of PDDA.

Preparation of Anion-Exchange Cellulose for the Removal of Chromate

“…The World Health Organization has recommended that the maximum allowable concentration of Cr(VI) in drinking water be 0.05mg/L [2,[7][8][9]. In order to reduce the Cr(VI) concentration to permissible level; adsorption, ion exchange, membrane processes, and polymeric sorbents were used [5,[10][11][12][13][14]. It should be noted that such methods can be ineffective or too expensive to treat wastes having metal ions in concentrations of 100 mg/L or below.…”

Water-Soluble and Insoluble Polymers, Nanoparticles, Nanocomposites and Hybrids With Ability to Remove Hazardous Inorganic Pollutants in Water

“…Future trends concerning to LPR technique involve the developments of hybrid methods. Those methods include the use of LPR as a pre or post treatment in combined methods such as chemical or electrochemical oxidation/reduction coupled to ultrafiltration using water-soluble polymers (Arar et al, 2014 ; Sánchez et al, 2015 , 2017 ; Chou et al, 2018 ). In addition, photocatalysis has been used in combination to LPR to remove improve removal capacities of arsenic (Yuksel et al, 2014 ; Molinari and Argurio, 2017 ).…”

“…The LPR technique was also used in the removal of Cr(VI) ions from aqueous solution using water-soluble poly(diallyldimethylammonium chloride), PDDA, and subsequent electrochemical reduction of Cr(VI) to Cr(III) (Sánchez et al, 2017 ). The enrichment method in LPR was used to determine the maximum retention capacity of the polymer, and the release of Cr(VI) and regeneration of the polymer were analyzed by sorption-desorption process.…”

“…Using the sorption–desorption process, the results indicated that this PDDA can release Cr(VI) and be regenerated. Finally, the electrolysis of Cr(VI) to Cr(III) was performed successfully in the presence of PDDA (Sánchez et al, 2017 ).…”

Poly(N,N-dimethylaminoethyl methacrylate) for removing chromium (VI) through polymer-enhanced ultrafiltration technique

“…Retention (%) of Cr(VI), q-values at Z=5 and polymer concentration in the feed determined for different polymer:Cr(VI) molar ratios. A C C E P T E D M A N U S C R I P T poly(diallyldimethylammonium chloride) 9 95 33 [32] N,N,N-trimethylchitosan chloride 8 94 48 [33] poly(glycidyl methacrylate-N methyl-D-glucamine) 3 60 21 [34] poly…”