Valorizing pig hooves for activated carbon production with efficient Methyl green adsorption, DFT insights and bacterial removal via bio-adsorbent column

Abstract

This study describes the use of a novel activated carbon (AC) adsorbent produced from pig hoove waste for the effective removal of Methyl Green (MG) from aqueous solutions. The AC, synthesized through KOH activation, boasts a substantial surface area of 334.031 m2/g and a total pore volume of 0.007 cm³/g. Comprehensive characterization was performed using proximate and ultimate (CHNS) analysis, BET, SEM, TEM, EDX, XRD, FT-IR, XPS, TGA, particle size analysis, zeta potential and zero-point charge (pHZPC). Adsorption data fit the Langmuir isotherm model exceptionally well (R2 = 0.99) indicating monolayer adsorption and followed pseudo-second-order kinetics implying chemisorption. The thermodynamic studies revealed that the adsorption of the MG dye is a spontaneous and endothermic phenomenon. Density Functional Theory (DFT) computations elucidated the adsorption mechanism, highlighting the critical role of oxygen functional groups. The AC’s unique properties enabled the development of a bio-adsorbent carbon column capable of removing Escherichia coli and Staphylococcus aureus from raw water samples with a 99% removal efficiency. The study also explored the potential for AC regeneration, demonstrating its versatility and sustainability for various applications. This research not only presents an efficient method for dye removal but also underlines the significance of repurposing waste materials, thereby supporting waste reduction and promoting eco-friendly practices for long-term environmental solutions and pollutant mitigation.