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

摘要

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.