SBA-15 demonstrates exceptional applicability as a heavy metal adsorbent carrier, however the absence of effective adsorption active sites on its surface limits its further application in the field of adsorption. Therefore, this study used 3-phosphorylpropionic acid as the functionalizing reagent to prepare carboxyl-functionalized SBA-15 (SBA-15C and SBA-15C-g) via a one-step co-condensation as well as post-grafting modification, respectively. The results showed that the carboxyl-functionalized SBA-15 still retained an ordered two-dimensional hexagonal mesoporous structure, and the surface of the SBA-15 was successfully functionalized with carboxyl groups. SBA-15, SBA-15C-2 and SBA-15C-g were used as adsorbents to study their adsorption performance on Cu(II) in solution. Under the optimized conditions, the adsorption capacity of Cu(II) by SBA-15, SBA-15C-2 and SBA-15C-g reached 30.4, 65.7 and 44.9 mg/g, respectively. Adsorption kinetics and isotherm analysis indicated that the adsorption of Cu(Ⅱ) onto SBA-15, SBA-15C-2 and SBA-15C-g was better described by the pseudo-second-order kinetic model and the Langmuir adsorption isotherm model. In addition, SBA-15C-2 maintained a high adsorption capacity of Cu(II) after five cycles. These results provide a theoretical basis for the carboxyl functionalization modification and practical application of SBA-15.
Liu et al. (Wed,) studied this question.