Fabrication of recyclable magnetic double-base aerogel with waste bioresource bagasse as the source of fiber for the enhanced removal of chromium ions from aqueous solution

Abstract

In this work, a magnetic double-base aerogel Fe3O4@bagasse@chitosan (FBC), waste bagasse as the source of fiber, chitosan as the substrate of Fe3O4@bagasse (FB), was synthesized by hydrothermal and freeze-drying method. The morphology, chemical and crystal structure of various stages of FBC aerogel synthesis were investigated. The influences of pH, contact time, temperature and other factors on Cr(VI) adsorption quantity were studied in the adsorption experiments, and the maximum adsorption capacity was about 41mg/g at 65°C. In addition, the adsorption isotherm was fitted by models of Langmuir and Freundlich, and the results demonstrated that the correlation coefficient R2 values (0.98, 0.97 and 0.98) of the Freundlich model were relatively high, compared with those (0.94, 0.94 and 0.91) of the Langmuir model at different temperature. The adsorption kinetic mechanism was explored by the traditional pseudo-first-order and pseudo-second order kinetic equations and the thermodynamic properties were ascertained by values of entropy change (−12.463kJ/moL) and enthalpy change (28.220J/molK). Moreover, the comparison with other adsorbents and the results of recoverability experiments indicated that the FBC is expected to be the preferred candidate for Cr(VI) removal in future water treatment, attributing to the advantages of environmental friendliness, economy and recyclability.