Synthesis of a Ni(ii) ion imprinted polymer based on macroporous–mesoporous silica with enhanced dynamic adsorption capacity: optimization by response surface methodology
In this study, a Ni(II) ion imprinted polymer (Ni(II)-IIP) based on macroporous–mesoporous silica (MMS) was optimally synthesized using a response surface methodology (RSM) approach for enhanced dynamic adsorption capacity. The MMS was prepared via dual-templating routes employing liquid crystalline surfactants and polystyrene beads to improve mass transfer and reduce transport limitations. With dynamic adsorption capacity for Ni(II) as the response, the effects of four variables, i.e. the amount of S,S′-bis(α,α′-dimethyl-α′′-acetic acid)trithiocarbonate (BDAAT), the consumption of acrylamide (AM), the reaction time and the dosage of 2,2′-azobisisobutyronitrile (AIBN), were investigated to solve the complex synthesis process. The predicted appropriate preparation conditions were as follows: BDAAT dose 0.07 g, AM dose 0.029 g, reaction time 6.3 h, and AIBN dose 4.54 mg, under which a Ni(II)-IIP was prepared and used as an adsorbent to remove Ni(II), obtaining the maximum dynamic adsorption capacity (12.96 mg g−1). The significance of independent variables and their interactions was studied to explain the specific adsorption question. In addition, the resulting Ni(II)-IIP was performed without any obvious deterioration after five repeated cycles.