Adsorptive removal of Cr(VI) from aqueous solution: kinetic, isotherm, thermodynamics, toxicity, scale-up design, and GA modeling

Chromium (VI) is a well-known toxic, industrial, water pollutant which has various, adverse effects on environmental health. Utilization of agricultural waste in effluent water treatment would minimize the problem of water pollution. The present study deals with the use of three types of nut shells for Cr(VI) removal. Adsorbents are characterized, using point of zero charges - (pH(pzc)), FTIR, BET surface area analysis, and SEM. The variation of different operating parameters on metal removal was conducted. The best sorption kinetic model was pseudo-second order. The adsorption process is both physical and chemical, and this depends on temperature. The Cr(VI) adsorption is spontaneous and endothermic. According to isotherm studies, Langmuir isotherm model fits fairly well for all adsorbents. Regeneration studies suggest that the adsorbents have proper regeneration criteria and can be used for multiple times. Study on RBC count of Gallus gallus domesticus gives concrete evidence of deadly effects of Cr(VI). It also figures out that the effluent solution treated with bio-adsorbents is less harmful. The scale-up design procedure is reported here. This study proved that groundnut shell, walnut shell, and almond shell have immense potential and can be utilized even after regeneration as replacement of commercial adsorbents for industrial wastewater. GA-ANN modeling has been developed for the best possible wastewater treatment management.