Adsorptive kinetic mechanisms of bromocresol green dye removal from wastewater using modified groundnut shell adsorbent

Abstract

This study explores the production and application of modified groundnut shell (MGNS) adsorbent to remove Bromocresol Green Dye (BCGD) from wastewater as an alternative to cost intensive wastewater treatment technologies. The adsorbent was characterized for physicochemical properties, and by employing Scanning Electron Microscope (SEM), Fourier Transform Infrared (FTIR) and Energy dispersive X-ray spectrometers (EDX) as characterization tools respectively. The effects of contact time on the percentage of dye recovery were evaluated. The kinetic data were fitted to kinetic models such as Brouers Weron Sotolongo-Coasta (BWS), Fractal Pseudo-second-order (FPSO), Pseudo-First-Order (PFO), Pseudo-second-order (PSO) models using a non-linear form of the equations. The results revealed that the biomass has a pH (6.60), moisture content (14.20) %, volatile matter, (10.20) %, Ash content (8.10) %, fixed carbon (65.50) %, bulk density (0.440) g/cm³, surface area (690) m²/g and particle size (250) μm. The adsorbent possesses high carbon content and a well-developed pore structure. The adsorbent percentage dye removal efficiency (% R) was time-dependent (30 min). The adsorbent has maximum percentage dye removal of 84% at the optimum time. The kinetic data that best described the removal of BCGD from wastewater was BWS (R² = 0.9644). Overall, the prepared adsorbent from MGNS was efficient, eco-friendly and economically viable in treating dye polluted wastewater, ensuring regulatory compliance and facilitating water reuse.