Adsorptive capture of fluoride ion from water by Co/Fe-LDH@Avocado kernel seeds biochar@Caboxymethylcellulose nanobiosorbent: Optimization, error function and multivariate analysis

The current investigation is devoted to synthesize a sustainable and effective nanobiosorbent by simple combination of cobalt-iron layered double hydroxide with avocado kernel seeds biochar and carboxymethyl cellulose to form a novel multifunctionalized Co/Fe-LDHs@AKS biochar@CMC material for adsorptive capture of fluoride under optimized conditions. The EDX analysis referred to 42.7 %(C) 33.4 %(O), 14.3 %(Co) 5.3 %(Fe) 2.6 %(Na) 1.2 %(Cl) and 0.52 %(Mn). The highest adsorptive capture of fluoride ion by Co/Fe-LDH@AKS biochar@CMC) nanobiosorbent were at pH ≤ 2.0 and pH 7.0 due to ion-pair interaction and anion exchange mechanisms. The fluoride removal achieved 90.9–100.0 % upon using 100 mg of Co/Fe-LDH@AKS biochar@CMC. The modeled data by four linear and non-linear expressions confirmed the highest average relative error (ARE) by the non-linear Jovanovich (ARE = 4.66) and linear Jovanovich (ARE = 12.69). The kinetic study ascertained that the adsorptive capturing reaction of fluoride ion was best fitted to both linear and nonlinear pseudo 2nd order.