Poly(benzoxazine-co-sulfur): An efficient sorbent for mercury removal from aqueous solution

A novel sulfur-rich adsorbent, poly(BA-ala-co-sulfur), was synthesized by reacting allyl functional benzoxazine (BA-ala) and elemental sulfur. Simultaneous inverse vulcanization and ring-opening reactions of benzoxazine generated copolymers in several feed ratios. The adsorption behavior of these copolymers was investigated in aqueous solutions containing Hg2+. A three level Box-Behnken design with four factors was applied in order to examine the interactive effect of Hg2+ concentration (ppm), S % in adsorbent, temperature, and pH. The optimum adsorption conditions were determined as: 10.33 ppm Hg2+, 68% S content, 329 K, and pH 6.3. Common isotherm and kinetic models were applied to the experimental data, where the Langmuir isotherm provided the better fit (q(max)=79.36 mg g(-1)) and the pseudo-second order fit indicated chemisorption as the process-controlling step. (C) 2017 Wiley Periodicals, Inc.