SYNTHESIS OF MESOPOROUS SILICA MODIFIED WITH 3-MERCAPTOPROPYLTRIMETHOXYSILANE FOR ADSORPTION OF SILVER NANOPARTICLES AND SILVER ION

Abstract

Silver nanoparticles are widely used in nano-consumer products and it may cause the contamination in environmental water source. Silver nanoparticles and the released silver ions have adverse effect on living organism and human. In this research, silica that had large pore size was prepared by sol-gel method using CTAB and citric acid as templates. The materials were characterized by x-ray diffraction and nitrogen adsorption analysis. The results showed that the silica synthesized by using citric acid template had the largest pore size (12.12 nm) and highest surface area (630.61 m2/g). The obtained silica was modified with 3-mercaptopropyl trimethoxysilane and characterized by thermal gravimetric analysis. The modified silica was used to adsorb silver ions and silver nanoparticles. The results showed that this silica can remove silver ions and silver nanoparticles from solutions. The suitable condition for adsorption silver ions was the initial pH 3 and 120 min of contact time. The suitable contact time for adsorption silver nanoparticles was 480 min. The adsorption behavior of silver ions followed pseudo-second order kinetics model and Langmuir isotherm with maximum adsorption capacity of 114.9 mg/g and the adsorption behavior of silver nanoparticles followed Langmuir isotherm with maximum adsorption capacity of 92.59 mg/g. Finally, this silica was successfully used to adsorb silver ions and silver nanoparticles in wastewater and nano-consumer product.