Adsorption of selected heavy metals on pretreated nanocellulose using Deep Eutectic Solvent (DES)

Abstract

In this studies, a method of producing cellulose nanocrystal (CNC) using deep eutectic solvent (DES) for the pretreatment of microcrystalline cellulose (MCC) with choline chloride (ChCl) and organic acids are reported. Malonic acid and Oxalic acid were studied as organic acid components of DES. MCC was used as a lignocellulose material. CNC from MCC was successfully produced by using ChCl and oxalic acid, whereas a low production yield of CNC was observed with ChCl and malonic acid. The lateral order index (LOI) and total crystallinity index (TCI) of CNC were found using Fourier Transform Infrared (FTIR) Spectroscopy. The LOI and TCI for CNC were found to be 1.29 and 1.03 respectively. CNC produced was used as a biosorbent for removal of silver nitrate, AgNO3 in aqueous solution. The adsorption study performed by varies the initial concentration of silver nitrate and contact time. The equilibrium adsorption capacity,qe increased as concentration and time increased. A biosorption studies on CNC was then fitted to Freundlich isotherm and pseudo-second-order by having a correlation coefficient value, R2, 0.9845 and 0.9993 respectively. Therefore, CNC produced from MCC using DES shows a good potential as an economical biosorbent for removal of silver nitrate by looking at the adsorption isotherm and kinetic results and it reveal versatile characteristics compared to CNC produced using strong acid in terms of easily to synthesis and design according to application, environmental friendly, biodegradable and low toxicity.