Cation-bioimprinted mesoporous polysaccharide/sol–gel composites prepared in media containing choline chloride-based deep eutectic solvents

A study on the Pb(II) imprinting performed within mesoporous sulphated biopolymer/siloxane composites, prepared in media containing deep eutectic solvent (DES), is described. In general, the process of imprinting resulted in greatly increased surface areas relatively to the corresponding nonimprinted composites up to fivefold (from 76 m² g^?1 to 360 m² g^?1) for fucoidan (Fuc) and up to twofold (from 208 m² g^?1 to 351 m² g^?1) for chondroitin sulfate (CS) composites], the diminishing of mean pore size (from 3.3–4.6 nm to 2.9–3.4), and higher biopolymer contents (from mass fractions of 0.42–0.52 to 0.46–0.68). The sorption features depended a great deal on the biopolymer/DES combination. The best CS composite, allowed for 12% capacity and 20% binding strength, as well as Pb(II)/Cd(II) selectivity enhancements. The largest of the capacities was obtained with the imprinted Fuc/DES-E composite, 86 mg g^?1, a 10% increase. Concerning the selectivity Pb(II) versus Cd(II)], there was a significant increase for the CS composites (from 1.0–1.1 (α_qmax)/1.1–1.2 (α_K) to 1.3–1.4 (α_qmax)/1.3–1.6 (α_K)]. In particular, the DES-E CIC presented high selectivity factors (α_qmax 3.0/α_K 3.2) in line with those of the microporous version (α_qmax 2.0/α_K 3.3) but showing a significant increase in terms of the α_qmax selectivity. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48842.