Polymeric Benzoxazine-Sulfur Embedded Chitosan Freestanding Beads as a Sustainable Facile Strategy for Remediation of Mercury and Oil

Environmentally benign sustainable origin greener sorbents for removing diverse pollutants in water are in huge demand to reduce pollution worldwide. Furthermore, heterogeneous nature and varied existence of pollutants, metal ions are dissolved in water while oil floats, demands a one-step efficient remedial solution. In current work, we have developed chitosan(CS)/poly(sulfur- ran -benzoxazine) copolymer-based hybrid composite beads with easy to use and recover after usage without secondary contamination of water bodies. CS is a naturally occurring second largest biopolymer; elemental sulfur (S) is industrial waste, cardanol (C) and furan (fa) are of agro-origin. The benzoxazine monomer and copolymerization with sulfur proceeded via a one-step (10 min.) solventless method. Then, the sulfur-benzoxazine copolymer is embedded in the CS using a facile strategy and revealed favorable interactions between the polymers for oil and Hg remediation. As a result, the CS/poly(C-fa- ran -S) hybrid composite beads outperformed with the removal and safe-locking of Hg 2+ ions (99.95%, only 2 ppb left in water filtrate, with high distribution coefficient of 1.9 × 10 5 mL.g −1 ) comparable to other related benchmarked materials. The Hg 2+ ion concentration is well below 6 ppb as desired by World Health Organization (WHO) guidelines for drinking water. Additionally, beads revealed good mechanical and hydrolytic stability and effectively removed crude oil (8 times the sorbent weight) efficiently with appreciable recyclability. The results suggest a great promise of waste-derived beads in tackling the diverse nature of pollutants for water purification applications