Synthesis of guar gum-g-coconut husk (SnO<SUB align="right">2-SiO<SUB align="right">2) nanocomposite for removal of Cu (II) and Cr (VI) from wastewater

Abstract

A new sorbent material namely 'guar gum-g-coconut husk (SnO2-SiO2) [GG-g-CH(SnO2-SiO2)] nanocomposite' was synthesised by preparation of coconut husk metal oxide nanoparticles and grafted into acrylamide modified guar gum (GG) base with the help of crosslinking agent glutaraldehyde. Its adsorption capacity was evaluated for the adsorption of Cu (II) and Cr (VI) metal ions from wastewater and factors affecting variables such as pH, adsorbent dose, contact time, and concentration were extensively investigated. It was found from the study that the maximum percent removal achieved was 99% for Cu (II) and 92.74% Cr (VI) at a pH of 8.3 and 7.2 respectively with an optimum adsorbent dose of 250 mg/l in 120 mins. The sorption data obeyed both Langmuir and Freundlich isotherms but Freundlich isotherm was better mathematical fit than Langmuir model. The Langmuir sorption capacity (qmax) was found to be 105.26 and 98.03 mg/g for Cu (II) and Cr (VI) respectively. Freundlich constants, KF values obtained for Cu (II) was 1.135 and for Cr (VI) was 1.11 while 1/n values obtained for Cu (II) was 0.647 and for Cr (VI) was 0.656, respectively.