Magnetized chitosan nanocomposite as an effective adsorbent for the removal of methylene blue and malachite green dyes

Herein, a magnetically separable Fe3O4 decorated chitosan was facilely synthesized, systematically characterized, and subsequently employed as a versatile adsorbing material for the adsorption of malachite green and methylene blue dyes. The prepared adsorbent was characteristically examined through Fourier transform infra-red microscopy, scanning electron microscopy with energy-dispersive X-ray analysis, transmission electron microscopy, X-ray diffraction, Brunauere-Emmette-Teller surface area analysis, thermogravimetric analysis, and vibrating-sample magnetometry techniques. The optimum process parameters for MB were observed to be 180 min of contact time, pH 7, and 1.2 g/L of adsorbent dose, and 210 min of contact time, pH 7, and adsorbent dose of 2 g/L was found to be for MG. The time-dependent experimental data were analyzed with different kinetic models, and pseudo-IInd-order was provided the best fit for the adsorption of both the dyes with a high value of the regression coefficient. The adsorption equilibrium data of both the dyes was best explained by Langmuir isotherm, and the maximum sorption capacity of MG and MB was found to be 55.86 and 76.34 mg/g, respectively. Thermodynamic analysis declared that the adsorption of MG and MB onto the Fe3O4 decorated chitosan was endothermic and spontaneous. Moreover, the adsorbent presented good reusability up to three successive ad-/de-sorption cycles, indicating that Fe3O4 decorated chitosan is a promising applicant for treating dye-containing wastewater.