Effective and fast adsorptive removal of fluoride on CaAl2O4:Ba nanoparticles: isotherm, kinetics and reusability studies

Abstract

Present systematic investigation, effective and rapid adsorptive removal of fluoride has been studied experimentally using optimized Barium doped calcium aluminate. Synthesized BCA nanoparticle characterized with analytical techniques like PXRD, FTIR, BET, pHPZC, SEM and EDS. During the adsorption process, to optimize dosage, various influencing parameters are carried out like pH (2–12), adsorbent dosage (0–50) mgl−1, contact time (0–50) min and adsorbate strength (0–30) mgl−1. Nonlinear modeling and statistical error analysis were computed and curve fitted using experimentally obtained equilibrium and kinetic data. Entire nonlinear parameters and statistical error functions solved using excel solver-2019. Among the experimentally computed data, Freundlich isotherm and pseudo-second-order kinetic models best fitted with R2 > 0.98. Maximum Langmuir adsorption capacity is 125 mgg−1 and free mean energy of fluoride adsorption EDR is 7.9 kJmol−1: Linear model suggests physisorption mechanism. From the statistical error analysis, PSO kinetic and D-R equilibrium model strongly recommended. Spent adsorbent reused for six cycles which are regenerated using 0.1 M NaOH. Adsorption of fluoride at 5 mgl−1 concentration is efficient in the presence of competing anions like SO42−, NO3−, Cl− and HCO3−. The experimental analysis concludes that adsorbent is an effective and well-organized adsorbent for the removal of fluoride from groundwater.