Fluoride removal from water using activated and MnO2-coated Tamarind Fruit (Tamarindus indica) shell: Batch and column studies

The present work is concerned with the defluoridation capacities of activated (ATFS) and MnO2-coated Tamarind Fruit Shell (MTFS), using batch and column sorption techniques. In the batch technique, the dynamics of fluoride sorption, with respect to pH, [F]o and sorbent dose, was studied. The applicability of pseudo-first order for ATFS and Ritchie-second order for MTFS was observed. The kinetics data were found to fit well with Temkin isotherm for ATFS and Langmuir for MTFS. The interaction of co-ions in the defluoridation capacity of the sorbent was studied. Column experiments were carried out under a constant fluoride concentration of 2 mg/l, flow rate and different bed depths. The capacities of the breakthrough and exhaustion points increased with increase in the bed depth for ATFS unlike MTFS. The Thomson model was applied to the column experimental results. The characterization of the sorbents, ATFS and MTFS, was done using the FTIR, SEM and XRD techniques.