Comparative study of waste derived adsorbents for sequestering methylene blue from aquatic environment

Our research work addressed the development and utilization of sugarcane baggasse, waste paper and Delonix regia seed pod derived adsorbents for the abatement of methylene blue (MB) from aquatic environment. The characterization of the developed adsorbents was investigated by N2 adsorption/desorption, scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), surface functionalities using Bohem titration and micro/macro-analysis. The adsorption capacity of activated sugarcane baggasse (ASB), delonix regia seed pod (ADSP) and waste paper (AWP) was observed to be 187.26, 153.84 and 99 mg g−1, respectively. Thermodynamic investigations established the exothermic and spontaneous nature of the adsorption with decrease in randomness at the solid/solution interface. A kinetic investigation has revealed that adsorption of MB followed a linear pseudo-second-order kinetic model. In column mode, the adsorption capacity of MB was found to be higher than batch mode of operation. The total cost incurred for the preparation of these activated adsorbents is USD 13.48 kg−1. This work highlighted that the developed materials are promising low cost adsorbents in sequestering MB from aqueous environment.