Experimental and modeling study on adsorption of emerging contaminants onto hyper-crosslinked cellulose

The primary objective of this study was to synthesize a novel hyper-crosslinked cellulosic adsorbent (CLC) by a straightforward one-pot esterification reaction using cellulose and sebacoyl chloride as crosslinker agent. Efficient crosslinking of cellulose was confirmed by FTIR, CPMAS 13 C NMR, elemental analysis, TGA, SEM and BET surface area analysis. The CLC material with high content of ester groups was employed to remove paracetamol (PCT) and niflumic acid (NFA) from aqueous solutions in batch adsorption experiments. The mesoporous structure of CLC created upon crosslinking was found to be a determinant in the adsorption behavior of the drugs. Indeed, PCT and NFA adsorption isotherms onto CLC were S-shaped and were adjusted by the Gu–Zhu, Frumkin–Fowler–Guggenheim and Hill–de Boer models. From the GZ isotherm model, the results indicate a cooperative adsorption mechanism leading to the formation of aggregates containing 2.53 and 4.25 molecules of PCT and NFA, respectively. Furthermore, FFG and HdB models reflect that the lateral interactions are attractive in nature for both drugs. The experimental kinetic data were fitted to the pseudo-second-order and intraparticle diffusion models, and the obtained parameters were linked to the aggregates arrangement of the drugs.