Adsorptive removal of fluoride ions from aqueous solution using activated carbon supported tetrametallic oxide system

Abstract

Elimination of superfluous accumulated fluoride from the environment has become a very serious environmental issue nowadays.In response to this prevailing environmental concern, the prime objective of the study is to fabricate a novel activated carbon supported tetrametallic oxide hybrid system for removal of fluoride where minimum amount of non-toxic metals are used. Here, the activated charcoal has been designed using indigenous raw materials and this serves towards making it a rational, cost-effective and green synthesis approach of the ACFM@AC adsorbent which leads to 3.15 mg g−1 adsorption capacity of fluoride. The adsorption performance of fluoride by ACFM@AC has been established by investigating its various equilibrium, kinetic and thermodynamic parameters which suggests that the adsorption process follows Freundlich isotherm and pseudo-second order kinetics with both physical and chemical adsorption mechanism. From the thermodynamic study, the Gibb’s free energy depicted to be in the range of − 73.15 kJ mol−1 to − 53.54 kJ mol−1 for the temperature range (298–313 K) while the enthalpy and entropy was found to be − 462.80 kJ mol−1 and − 1.30 kJ K−1mol−1 respectively which suggests the adsorption process to be spontaneous, feasible and exothermic with decrease in randomness.