Surface-Modified Adsorbent from Artocarpus heterophyllus Lam Biomass to Confine Reactive Red 194 in Real and Synthetic Effluents: Kinetics and Equilibrium Study

Abstract

Chemical activation of Artocarpus heterophyllus Lam (jackfruit peel) via phosphoric acid was focused on this study for the preparation of activated carbon. Carbonization was done at a temperature of 400°C based on the nature of biomass after the impregnation ratio of 1 : 1 (weight of phosphoric acid/weight of raw material). Titanium dioxide was doped on the prepared activated carbon through the sol-gel method. Titanium dioxide doped activated carbon was synthesized to perceive the nature of adsorbents under ambient conditions. Both JPAC and JPAC/TiO2 adsorbents were characterized by the point of zero charges, Fourier transform of infrared spectroscopy, X-ray diffraction spectroscopy, Brunauer-Emmett-Teller analysis, and scanning electron microscopy with energy-dispersive X-ray analysis. The adsorption capacity of Reactive Red 194 (Red 2BN) dye on jackfruit peel activated carbon (JPAC) is 32.271 mg/g, and JPAC/TiO2 is 34.900 mg/g was observed under optimum conditions. Desorption efficiency of JPAC/TiO2 (≥93.4%) is slightly higher compared to JPAC (≥89.2%). Tannery effluents of various parameters were analyzed, and their chemical oxygen demand (COD) values trim down within the permissible limits of JPAC (97%) and JPAC/TiO2 (98%). Experimental data were studied using both two-parameter and three-parameter models of adsorption isotherm, namely, the Langmuir, Freundlich, Temkin, Dubinin-Radushkevich, Redlich-Peterson, Sips, Toth, and Khan. In which the Langmuir isotherm ( $R2=0.9824$ ) best described the experimental data with an optimum monolayer capacity for adsorption capacity of 49.7 mg/g at 323 K on Red 2BN molecules. A proposed scheme of Red 2BN molecules on the active sites of adsorbents was illustrated. Regeneration of spent carbons was studied through different cycles of the run.