Removal of molybdate and vanadate ions by a copolymer adsorbent in a ultrafiltration system

Abstract

In this investigation, the removal of Mo and V oxyanions was carried out using the polymer-assisted ultrafiltration technique with a poly(acrylamide-co-diallyldimethylammonium chloride) [P(AAm-DDACl)]. As a result, 100% of the Mo and 80% of the V were removed at pH 9 with a polymer:metal molar ratio of 10:1 and an optimal metal concentration of 60 mg L −1 . The presence of competitive ions such as phosphate, sulfate, and chloride affected the retention of Mo, decreasing its retention to 60% in all cases. For the V, all competitive ions behaved in a similar way, producing approximately 50% metal removal. The permeate flux was kept almost constant for all solutions (40 to 80 L hm −2 ), which indicates that the optimal retention conditions are stable over time. In addition, the characterization of the P(AAm-DDACl) was carried out using infrared spectroscopy analysis (FTIR), and the morphology of the membrane before and after use was analyzed using scanning electron microscopy, which showed significant changes in its morphology. The energy-dispersive X-ray spectroscopy analysis indicates the presence of Mo and P(AAm-DDACl) in the membrane after use.

Chromate ion removal by water‐soluble functionalized chitosan

“…This decrease in flux with the addition of interfering ions is due to the increase in electrostatic interaction in the solution, presenting formations of small precipitates causing severe polarization effects in the membranes, which is reflected in the process of fouling and low fluxes. The effect of polarization and fouling can be due to different factors, such as sorption on the membrane surface, depositions on the adsorbed layer, and compression of the membrane layer 53,54 …”

Removal of Dyes by Polymer-Enhanced Ultrafiltration: An Overview

“…Consequently, a permeate with little or no presence of colorants is obtained [ 80 ] (see Figure 3 ). In general, water-soluble polymers can be classified into two categories: polyelectrolytes (polymers with charged groups in their repeating units) and polychelatogens (chelating polymers that contain chelating groups or complexes) [ 15 , 68 , 88 , 89 , 90 , 91 , 92 , 93 , 94 ]. However, the most commonly used WSP for the removal of dyes in aqueous solution are polyelectrolytes.…”

“…However, the most commonly used WSP for the removal of dyes in aqueous solution are polyelectrolytes. These contain groups easily ionizable in water, such as -OH, -COOH, -NH 2 , -HSO 2 [ 28 , 68 , 88 , 89 , 90 , 91 , 92 , 93 , 94 ], which are able to obtain polymers in solution with a positive or negative charge, called anionic or cationic polymers. The high content of functional groups contributes to the extractant properties of these compounds [ 28 , 95 , 96 ].…”

“…The high content of functional groups contributes to the extractant properties of these compounds [ 28 , 95 , 96 ]. The ionic nature of polyelectrolytes in solution generally induces electrostatic or ion exchange attractions between adsorbate–adsorbent [ 15 , 68 , 88 , 89 , 90 , 91 , 92 , 93 , 94 ]. The use of easily ionizable WSPs facilitates the uptake of acidic and basic dyes in the PEUF process, where acid dyes are attracted to cationic polymers and basic dyes to anionic polymers, respectively [ 2 , 72 , 75 ].…”

Liquid-Phase Polymer-Based Retention to Remove Arsenic From Water

“…The removal of arsenic from aqueous solutions using ultrafiltration assisted by a water-soluble polymer, also called the liquid-phase polymer-based retention (LPR) technique has been studied. In this technique, a water-soluble polymer is used as a polymeric extractant, and a ultrafiltration membrane is used as a filter [85]. The combination of a water-soluble polymer with ultrafiltration membranes could represent an alternative method for the removal of metal cations and oxyanions from aqueous media.…”