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Crosslinked polyDADMAC gels as highly selective and reusable arsenate binding materials

2015-02-15
Pirgalioglu, Saltuk
Ozbelge, Tulay A.
Özbelge, Hilmi Önder
Bicak, Niyazi
High porosity cationic hydrogels synthesized via crosslinking co-polymerization of diallyldimethylammonium chloride (DADMAC) with N,N'-tetraallylpiperaziniumdichloride (TAP) showed high affinity towards arsenate anions over a wide pH range within notably short periods. Batch tests indicated that poly(DADMAC) hydrogels removed 99% of the arsenate anions from aqueous solutions at pH 6-10 and exhibited a maximum arsenic removal capacity of 0.12 g arsenic per gram of hydrogel. DADMAC hydrogels performed well at various pH levels after a short contact time (i.e., 10 min). Evidence of the ion exchange mechanism was based on experiments with solutions containing competing chloride and sulfate ions. An "intra-particle diffusion model" was proposed for the kinetics of arsenic removal. This gel was determined to be a good candidate for use in practice due to its easy regeneration either by treating with a 8.24 g/L of NaCl solution or by reducing the pH of the medium to below 1.0.