Chemically reduced tea waste biochar and its application in treatment of fluoride containing wastewater: Batch and optimization using response surface methodology

Pyrolysis of domestic tea waste was carried out to yield bio-char which was further chemically treated using Hummer's method to form carbonaceous materials. Hummer's method is generally used to prepare graphene oxide (GO) from carbon source and it was observed from XRD, SEM and FTIR analysis that the structure of the synthesized biochar is similar to reduced GO. The adsorbent thus obtained was further applied for the treatment of fluoride containing simulated effluent. Effect of different experimental parameters on the fluoride removal efficiency using chemically reduced biochar and only tea waste biochar were investigated. Data obtained was further used for determination of process isotherms, kinetics and thermodynamics. The experimental results suggested that equilibrium adsorption data was strongly guided by the Langmuir isotherm and pseudo-second-order kinetics. Significant process parameters were optimized using Response surface methodology (RSM). Under optimized conditions, fluoride removal efficiency using chemically reduced biochar was found to be 98.31%.