DFT theoretical analysis and experimental approach combination to understand the toxic dye's adsorption mechanism on the corncob-activated carbon surface

Abstract

The textile industry generates high liquid effluent volume that disrupts economic growth and ecological security. This research article aims to prepare corncob-activated carbon (CC-AC) for Acid Green 50 (AG50) toxic dye effective removal and to characterize the adsorbent by FTIR, SEM-EDX, TGA/DTG, pHpzc, and Boehm surface functions. The maximum amount of adsorption, according to kinetic studies, was about 47.9 mg g−1 under the adsorbent dose 1 g L−1, [AG50]=50 mg L−1, and pH 6.8. The experimental results of anionic dye AG50 adsorption on the CC-AC surface were in agreement with the response surface approach predicted values and resulted in an optimum removal rate of 95.03% at an adsorbent dose of 1 g L−1, dye concentration of 10 mg L−1, and pH 2. Density function theory (DFT) was used to perform quantum chemistry B3LYP6–31 G (d,p) computations to bind their electrical characteristics with the experimental results. The acidic form of AG50 has a higher HOMO energy than the basic form, indicating that it is more reactive to transfer an electron from the last filled orbital to an empty orbital. Cost analysis, regeneration, and germination tests demonstrate that CC-AC is non toxic, inexpensive ($ 1.15 per 1 g), and environmentally friendly.