Thermal effects on Vigna subterranean wastes: Enhanced porosity, morphological appearance and preliminary adsorption studies

The search into new and efficient material to replace activated carbon in adsorption has been of great importance to researchers. Agricultural wastes is found suitable to satisfy this quest. Types of treatment are fundamental to the efficiency of biosorbents. Due to copper's toxicity, the removal of excess copper ions is critical for maintaining human health and ecological structure. The influence of thermal treatment on surface morphology and surface chemistry of Vigna subterranean wastes was investigated. The improved porosity was substantiated by the Brunauer-Emmett-Teller (BET) surface area (11.7314 m
²
/g), this is more than ten times higher than that of raw Vigna subterranean wastes (VSW). Fourier Transformed Infrared (FTIR) Spectroscopy presented disappearance or reduction in intensity of functional groups such as -OH, C=O, C-OH. The adsorption studies showed that TVSW would be most effective in the adsorption of Cu
²⁺
at pH of 5.0. The data from the Cu
²⁺
adsorption experiment were better described by the Freundlich isotherm model, whereas the uptake was in accordance with the Pseudo second order kinetic model (R
²
= 1.0000). The highest amount of Cu
²⁺
adsorbed was 86.96 mg/g.