Removal of As(III) and As(V) from aqueous solution using engineered biochar: batch and fixed-bed column study

Magnetic biochar materials were developed using waste dry leaves of Tectona species (Teak) and Lagerstroemia speciosa (Banaba plant). The adsorption efficiency of these synthesized biochar was examined for As(III) and As(V) adsorption from an aqueous solution and natural groundwater. The biochar was characterized via point of zero charge (pH(ZPC)), energy dispersive X-ray, scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, Raman spectroscopy, zeta potential, and particle size analysis. Both the magnetic biochar were found to be potent in adsorbing As(III and V) from aqueous solution and groundwater samples. The maximum adsorption of As(III) was 92.1% and 97.8%, respectively, by MTB-800 and MLB-800. However, the highest As(V) adsorption was 94.7% and 96.7%, achieved by MTB-800 and MLB-800, respectively, at lower initial As concentrations. The adsorption process was well-fitted to the Langmuir model of isotherm and pseudo-second-order kinetic. The reusability test of the biochar revealed that biochar can be successfully reprocessed up to five cycles. Different models were directed to evaluate the breakthrough curve obtained in column study. As per the available literature, the waste biomass (Teak and Banaba plant) utilized in this study was first time infused with FeCl3 for biochar synthesis development of magnetic properties and applied for As removal. As these magnetic biochar effectively adsorbed arsenic from synthetically prepared As solution as well as from groundwater at laboratory level so, these can be utilized for low-cost filter development to eradicate the problem of arsenic from arsenic-prone areas.