ADSORPTION OF ARSENITE AND ARSENATE BY POLY(3-ACRYLAMIDOPROPYL)TRIMETHYLAMMONIUM-CHLORIDE-MODIFIED WASTE TYRE RUBBER

Abstract

Waste tyre rubber (WTR) powder was modified with cationic polymer, poly(3-acrylamidopropyl)trimethylammonium chloride (p(APTMACl)) which was synthesized by free radical polymerization in aqueous solution. The resulting WTR/p(APTMACl) was utilized as adsorbent for the adsorption of arsenite and arsenate from aqueous medium at room temperature. It was effective in the adsorption of arsenite and arsenate via physisorption and ionic exchange. Various parameters were optimized the preparation and utilization of this WTR/p(APTAMCl) for arsenite and arsenate adsorption in both batch and column methods. The optimal pH for the arsenite and arsenate adsorption was 6 and 8, respectively. The adsorption increased gradually with increasing the monomer concentration and contact time. Comparing drying temperatures between 50 and 100 ºC, the adsorption amount of arsenate was higher at the lower drying temperature. The arsenite and arsenate adsorption behavior obeyed the Freundlich model with the R² of more than 0.91 and 0.98, respectively, indicating that the adsorption occurred on a heterogeneous surface. The rate of arsenite and arsenate adsorption could be predicted with the pseudo-second order model. The sorbent was subsequently packed into a column and used for the adsorption of arsenite and arsenate with an optimized flow rate at 0.85 mL/min with a weight of 0.65 g. In the column method, arsenate could be adsorbed onto the sorbent better than arsenite. Arsenite and arsenate extraction was 0.014 and 0.077 mg/g, respectively. Both of these two arsenic species showed lower adsorpabilty than that in the batch method. The remarkable desorption of arsenite and arsenate from the sorbent using 0.10 M HCl as eluent was achieved as 99 and 92%, respectively. Moreover, the sorbent showed a promising adsorption of arsenic from real wastewater.