Chitosan-Quinoa Bran Aerogel: A Low-Cost, Highly-Efficient, and Recyclable Adsorbents for Wastewater Treatment

Organic dyes and heavy metals are major contaminants in water seriously threatening human lives. In this work, we designed and fabricated a chitosan (CS) and quinoa bran (QB) aerogel for the adsorption of Congo red (CR) and Cu2+. The ice-templated assembly method was introduced to fabricate CSQB aerogel. SEM, FTIR, XRD, TGA, BET, and XPS were applied to characterize as-prepared aerogel. The adsorption properties of CSQB aerogel for CR and Cu2+ were investigated in different conditions, including initial concentrations, temperature, pH, and contact time. The adsorption kinetics results indicated that the adsorption of CR and Cu2+ follows pseudosecond-order and pseudofirst-order models, respectively. The adsorption isotherm analysis indicated that the Langmuir isotherm gave a better fit for the adsorption of CR and Cu2+ compared with the Freundlich isotherm. According to the Langmuir isotherm, the maximum monolayer adsorption capacities of CSQB for CR and Cu2+ were 182.48 and 96.25 mg/g, respectively. Besides, its removal efficiency for CR and Cu2+ only decreased 14.47% and 16.97% after five cycles of adsorption-desorption experiments in reusability tests. Therefore, this study provides a low-cost, highly efficient, and recyclable strategy for removing organic dye and heavy metal from wastewater.