Synergistic adsorption-Fenton degradation of organic pollutants by MIL-88B/montmorillonite and cellulose nanocrystals functionalized gelatin composite aerogels

Abstract

In this work, MIL-88B loaded montmorillonite (MMT) and cellulose nanocrystals (CNC) were incorporated into gelatin (G) aerogel to yield a multifunctional and reinforced bio-aerogel, named as MMCG aerogel, for removing organic pollutants by synergistic adsorption and Fenton degradation. As expected, the MMCG aerogels exhibited highly efficient adsorption capacity for charged pollutants. The adsorption process of methyl blue (MB) followed well with Langmuir isotherm, while tetracycline hydrochloride (TCH) and methylene blue (MEB) could be better fitted by Freundlich isotherm. The adsorption kinetics were accurately described by the pseudo-second-order kinetic model. Thermodynamic experiments revealed that the adsorption process was endothermic and spontaneous. The maximum adsorption capacities for MB, MEB and TCH were 1494.47 mg/g, 952.26 mg/g and 701.82 mg/g, respectively. Electrostatic interactions, hydrogen bonds and π-π interactions may be responsible for the adsorption mechanism. Most importantly, it exhibited better removal performance for all organic contaminants with or without charged states by triggering the Fenton reaction with the addition of H2O2. For the non-adsorbed bisphenol A (BPA) with uncharged state, the removal efficiency after Fenton degradation significantly increased from 4.73 % to 86.13 %. Additionally, it had excellent recyclability. Therefore, the MMCG aerogel could be recognized as a promising material for wastewater treatment.