A green synthesis method of a mussel-inspired polyphenol-functionalized silica-based material and its highly efficient adsorption of gallium

Abstract

Three-dimensional mesoporous silica is a distinctive nanomaterial celebrated for its unique structure, substantial specific surface area, enhanced utilization of active surfaces, and improved adsorption and catalytic reaction capabilities. Nevertheless, its limited surface functional groups often impede its effective ion adsorption capacity. Here, inspired by the mussel-adhesive phenomenon, in this study, we introduced a straightforward layer-by-layer assembly approach to fabricate a new series of KIT-6@x-catechol/polyethyleneimine composites, the catechol/polyethyleneimine is the shell and KIT-6 is the core. Importantly, catechol(CA) and polyethyleneimine(PEI) polymers as selective layers with dense structures and abundant cation exchange groups, resulting in outstanding adsorption performance for our material. At a pH of 3.0, Ga(III) exhibited a maximum adsorption capacity of 88.65 mg g−1 on the adsorbent. Furthermore, the adsorbent demonstrated selective adsorption capabilities for Ga(III) over Ge(IV), Al(III), Cu(II), Zn(II), and Co(II). The primary adsorption mechanism of KIT-6@x-CA/PEI is chelation that occurs through coordination between the O atom on the phenolic hydroxyl group of CA and Ga3+, Ga(OH)2+, Ga(OH)2+ under pH 3.0 conditions. In summary, the synthesized KIT-6@x-CA/PEI exhibits significant potential for water treatment containing Ga(III) through adsorption processes.