Synthesis of carboxylated nanocrystalline cellulose reinforced hydrogels for the removal of organic pollutants

Abstract

This research work demonstrates the synthesis of hydrogels by using functionalized nanocrystalline cellulose with synthetic monomers and their performance in the removal of methylene blue as the model organic pollutant. Microcrystalline cellulose (MCC) was used as the starting material for the preparation of nanocrystalline cellulose (NCC) through hydrolysis with sulfuric acid. NCC was selectively oxidized to synthesize Dicarboxylated nanocrystalline cellulose (DCNC) via dialdehyde nanocellulose (DANC). Then hydrogels were prepared by a free radical polymerization of acrylic acid and acrylamide in presence of DCNC, initiator potassium persulphate, and cross-linker MBA (N, N′ Methylene bis Acrylamide). The morphological, thermal, and mechanical properties were carried out by SEM, TG, DSC, and UTM. The surface morphology analysis showed that the prepared hydrogels are highly porous. The higher thermal stability of the synthesized gel was achieved in comparison with the gel prepared without DCNC. The test of mechanical properties suggested that DCNC has impacted the hydrogels highly, thus young’s modulus, and tensile strength have been improved than the neat AAC and AAM hydrogel. Although the DCNC-AAM hydrogel showed slightly higher mechanical properties, the DCNC reinforced acrylic acid hydrogel has represented greater removal percentage (95%) and adsorption capacity (2225 mg/g) at pH 9 than neat AAC (76%) and AAM (8%) based hydrogels. The findings suggested that the synthesized hydrogel is a potential candidate with a very high removal efficiency for the removal of organic pollutants from wastewater.