Precipitated droplets in-situ cross-linking polymerization towards hydrogel beads for ultrahigh removal of positively charged toxins

Abstract Green, simple and fast approach towards functional spherical hydrogels with excellent adsorption capacity of toxins remains a huge challenge. Herein, we developed a novel approach to fabricate functional spherical hydrogel absorbent in 40 s without any post-treatments, for which only water and corn oil were used as green solvents. Acrylic acid (AA) and 2-acrylamido-2-methyl-propanesulfonic acid (AMPS) were selected as functional monomers to produce P(AA-co-AMPS) hydrogel spheres via precipitated droplets in-situ cross-linking polymerization. Various mass ratios of monomers for the preparation of functional spherical hydrogels were tested to obtain the maximum removal of positively charged toxins. As a result, the adsorption amounts of methylene blue (MB) and Pb2+ could reach as high as 4463.3 and 6393.4 mg/g, respectively. In addition, the particles showed a stable adsorption capacity for at least three desorption-resorption cycles. Therefore, we prepared promising absorbents for ultrahigh removal of positively charged toxins via chemical cross-linking during processing, and the proposed green, one-pot and fast approach has great potential for industrial production of functional spherical hydrogels.