Chitosan extraction from lobster shells and its grafted with functionalized MWCNT for simultaneous removal of Pb2+ ions and eriochrome cyanine R dye after their complexation

Abstract

Chitosan (CS) extracted from lobster shells (Persian Gulf, Iran), was grafted with amino functionalized multiwalled carbon nanotube (MWCNT). This novel material was characterized by FE-SEM and FT-IR and used for the ultrasound-assisted removal of Pb²⁺ ions and eriochrome cyanine R (ECR) dye. A central composite design (SCCD) under response surface methodology was used for studying the influences of important variables in removal process such as initial ECR and Pb²⁺ ions concentrations, adsorbent mass and sonication time on the removal efficiency. Linear, 2FI, quadratic and cubic models were performed and a quadratic model was selected for analysis of each response. ANOVA for the quadratic model shows the F-value parameter (820.44 and 537.12 for ECR and Pb²⁺ ions removal, respectively) and very low p-value (<0.0001), implying that the model was highly significant for understudy analytes adsorption. To achieve maximum removal, the optimum condition was determined and were set as:19.34 and 18.20mgL^-1,0.018g and 9.35min for initial ECR and Pb²⁺ ion concentrations, adsorbent mass and sonication time, respectively. At these optimum conditions, 97.06% of ECR and 99.29% of Pb²⁺ ions were removed in a short time.

Keywords: Chitosan; Eriochrome cyanine R; Multiwalled carbon nanotubes; Pb(2+); Quadratic model.