Assessment of Surface Properties of Benincasa Hispidia and Cucurbita peels for Chromium Uptake

Abstract

This study investigates the chromium adsorption feasibility by agricultural waste based activated ash gourd (AGP) and activated pumpkin peels (APP) by employing Kinetic models (Intra – particle diffusion, Elovich, First order and Second order models) and  non – linear isotherms (Langmuir and Freudlich) models. The surface morphology and pore size distribution of AGP and APP were measured using Scanning Electron Microscope (SEM), Energy Dispersive X-ray Measurements (EDAX), and Brunauer Emmett Teller (BET). The adsorption data reveals fixing on Elovich equation with correlation coefficient (R²) of 0.97 and 0.94 respectively for AGP and APP as compared to 0.89 and 0.91 for diffusion model. These finding suggest the predominantly physical adsorption behaviour of total chromium by both the adsorbents.  Freundlich’s isotherm model showed a better fit than Langmuir’s equation for AGP and APP with lesser Chi square (ꭓ²) error of 0.31 and 1.11 respectively against that of Langmuir with 8.11 and 11.14 indicates the heterogeneous surface of these agricultural based adsorbents.