A sorbent containing pH-responsive chelating residues of aspartic and maleic acids for mitigation of toxic metal ions, cationic, and anionic dyes

t-Butyl hydroperoxide-initiated cycloterpolymerization of diallylaminoaspartic acid hydrochloride [(CH(2)[double bond, length as m-dash]CHCH(2))(2)NH(+)CH(CO(2)H)CH(2)CO(2)H Cl(−)] (I), maleic acid (HO(2)CH[double bond, length as m-dash]CHCO(2)H) (II) and cross-linker tetraallylhexane-1,6-diamine dihydrochloride [(CH(2)[double bond, length as m-dash]CHCH(2))(2)NH(+)(CH(2))(6)NH(+) (CH(2)CH[double bond, length as m-dash]CH(2))(2) 2Cl(−)] (III) afforded a new pH-responsive resin (IV), loaded with four CO(2)H and a chelating motif of NH(+)⋯CO(2)(−) in each repeating unit. The removal of cationic methylene blue (MB) (3000 ppm) at pH 7.25 and Pb(ii) (200 ppm) at pH 6 by IV at 298, 313, and 328 K followed second-order kinetics with E(a) of 33.4 and 40.7 kJ mol(−1), respectively. Both MB and Pb(ii) were removed fast, accounting for 97.7% removal of MB within 15 min at 313 K and 94% of Pb(ii) removal within 1 min. The super-adsorbent resin gave respective q(max) values of 2609 mg g(−1) and 873 mg g(−1) for MB and Pb(ii). IV was also found to trap anionic dyes; it removed 91% Eriochrome Black T (EBT) from its 50 ppm solutions at pH 2. The resin was found to be effective in reducing priority metal contaminants (like Cr, Hg, Pb) in industrial wastewater to sub-ppb levels. The synthesis of the recyclable resin can be easily scaled up from inexpensive starting materials. The resin has been found to be better than many recently reported sorbents.