Characterization and Performance of Hollow Silica for Adsorption of Amoxicillin in Aqueous Solutions

Two kinds of hollow silica materials, namely H-SiS1 and H-SiS2, were synthesized using the yeast template method and the Pickering emulsion polymerization method, respectively. The adsorbents were synthesized to adsorb amoxicillin (AMX) from an aqueous environment. Characterization results indicated that hollow silica adsorbents exhibited excellent thermal stability even at temperatures above 700 °C. Several batches of static adsorption experiments were prepared to analyze the adsorption performance on AMX. Isotherm data on different adsorbents fitted well with the Langmuir model (from 15 °C to 35 °C), indicating a monolayer molecular adsorption mechanism for AMX. The maximum adsorption capacities of H-SiS1 and H-SiS2 were 8.40 and 3.46 mg/g at 35 °C, respectively. The adsorption kinetics was described well by the pseudo-second-order model, which indicated that chemical interactions were primarily responsible for AMX adsorption and could be the rate-limiting step during adsorption. These results suggested that H-SiS1 could be significantly useful as adsorbents for removal of AMX residuals from aqueous solution.