Removal of silver nanoparticles from aqueous solution using cellulose extracted from Traganum Nudatum plant activated by zinc chloride

Abstract

The production and excessive use of silver nanoparticles pose many environmental and health risks. Where they are released from various products associated with it into water sources. Adsorption using suitable adsorbent materials is an effective and commonly used method for treating water pollution. In this study, activated cellulose using zinc chloride was proposed to remove silver nanoparticles from aqueous solution. Various measurements such as UV-Vis, TEM, DLS, Zeta potential, FTIR, EDXRF and pHpzc were used to characterize the silver nanoparticles and activated cellulose. The results showed that the average size of obtained silver nanoparticles was 75 nm and their average hydrodynamic diameter ranged between (88.05 and 495.1 nm). The silver nanoparticles had a polydispersity index (PDI) ranging between (0.329–0.526). silver nanoparticles had a negative surface charge ranged between ((-3.74) - (-9.63) mV). FTIR and EDXRF measurements confirmed the presence of silver nanoparticles on the surface of activated cellulose after completing the adsorption process. The adsorption capacity increased with increasing the initial concentration and ionic strength, while it decreased with an increase in adsorbent dose and temperature. The highest adsorption capacity was obtained at pH= 9 and a contact time of 20 min. The highest obtained adsorption capacity is 405.75 mg.g⁻¹ and the highest obtained removal percentage is 99.45 %. Adsorption kinetic models show that the removal process follows a pseudo-second-order model. The adsorption isotherms models indicate that the removal process follows the Langmuir isothermal model. Adsorption thermodynamic parameters indicate that the adsorption process is spontaneous, exothermic and random. This study indicates that the adsorption of silver nanoparticles onto the surface of activated cellulose was physisorption.