Fast and efficient adsorption of Ag nanoparticles by sodium montmorillonite nanoclay from aqueous systems

Abstract

Silver nanoparticles (AgNPs) are, due to their antimicrobial properties, the most widely used nanoparticles in commercial products. AgNPs are incorporated into medical products such as bandages, as well as in textiles and household items. Besides its antimicrobial effect, exposure to soluble silver compounds produce toxic effects on all living organisms. In this work, the removal of Ag nanoparticles (AgNPs) using aqueous sodium montmorillonite nanoclay in the presence of a cationic surfactant stabiliser was investigated. The effects of experimental parameters on the adsorption process, such as pH, surfactant concentration, adsorbent dosage, initial AgNPs concentration and contact time, were studied. The Langmuir and Freundlich isotherm models were applied and the Langmuir model was found to best fit the equilibrium isotherm data. Langmuir adsorption capacity was found to be 71.4 mg g-1 of AgNPs at pH 7. The results indicate that sodium montmorillonite nanoclay can be used for the fast and efficient removal of AgNPs from aqueous solutions.