Preparation of an ecofriendly chitosan–ZnO composite for chromium complex dye adsorption

Abstract

Three chitosan‐ZnO composites were prepared by the chitin deacetylation process using zinc chloride as source material and sodium hydroxide as precipitant. The physical characteristics of chitosan‐ZnO composites were studied using Fourier Transform infrared spectroscopy and scanning electron microscopy. The adsorption of a chromium complex dye onto commercial chitosan, prepared chitosan and chitosan‐ZnO composites was investigated in aqueous dye solution. Dye calibration was carried out by UV‐vis spectroscopy. The calculated dye adsorption values for commercial chitosan, prepared chitosan, and chitosan‐ZnO composite samples are 0.0086, 0.0137, and 0.0214 mg/g respectively, indicating that the chitosan‐ZnO composites have better dye adsorption capacity than commercial chitosan and prepared chitosan. The experimental isotherm data for the composites fitted the Langmuir isotherm model well. Thus, the chitosan‐ZnO composites can be used as an effective biosorbent for the removal of anionic dyes.