LAUSR

Abstract Large pore mesoporous silica was synthesized using citric acid as template and modified with mercaptopropyl trimethoxysilane. The MP-Silica exhibited a surface area of 474 m2 g−1 with an average pore diameter of 11 nm (pore diameter ranging from 2 to 30 nm). The material was used in the adsorption of silver ions, AgNPs and simultaneous adsorption of these silver species was also observed. The adsorption of silver ions occurred rapidly and followed a pseudo-second order kinetic model. The adsorption equilibrium of silver ions could be described with a Langmuir isotherm and the maximum adsorption capacity was found to be 114.9 mg g−1. In the mixture of AgNPs and silver ions, the adsorption of AgNPs followed a pseudo-second order kinetic model and took place more slowly compared to silver ions due to their larger size. The MP-Silica exhibited a maximum adsorption capacity of 91.9 mg AgNPs g−1 in the mixture. The adsorption of silver species on MP-Silica occurred through chemisorption via the coordination of these species with thiol groups on the surface. The removal of silver species from wastewater samples and consumer products by MP-Silica was demonstrated.