Efficient Removal of Methyl Orange on Chitosan-Dialdehyde Pectin Film Elaborated via Schiff Base Reaction

The aim of this study was the elaboration of a chitosan/oxidized pectin film for use in the adsorption of methyl orange. To valorize the food waste from juice manufacturing, pectin was extracted from orange peel waste. The highest extraction yield of 21.1% was achieved at a temperature of 80 °C, a time of 50 min, pH of 1.5, and a liquid-to-solid ratio of 25:1 (v/w). Chitin was extracted from shrimp shells through acid and alkaline treatment. The deacetylation of chitin to chitosan was carried out using a 40% NaOH treatment with a liquid-to-solid ratio of 4:1. The conversion of pectin to its dialdehyde derivatives by periodate oxidization in acid solutions with pH 4 at 35 °C has been investigated. The prepared chitosan-dialdehyde pectin films, elaborated via Schiff base reaction, were characterized using FTIR and XRD analyses. The results of methyl orange adsorption showed an efficiency that can reach 100%. The adsorption data were best described by the Freundlich isotherm and the pseudo-second-order kinetic model, indicating a heterogeneous surface and a chemisorption-dominated process.