The Assessment of the Adsorption Capacity of Sorghum Husk for Phenol Remediation

Phenol is used in many industries; hence, effluents from these industries should be treated properly in order to avert environmental pollution. One of such treatment methods is adsorption, where agricultural waste such as sorghum husk can be used as adsorbents. The main purpose for carrying out this research was to ascertain the efficacy of sorghum husk (SH) as an adsorbent for remediating phenol from water. The SH was characterized with the use of pH at zero point charge (pHzpc), Fourier transforms infrared (FTIR) spectroscopy and Sear’s surface area analysis. The effects of some factors that affect adsorption were examined in batches. The data emanating from the adsorption batch experiments were analysed with isotherm and kinetic models. Thermodynamic parameters that examine the adsorption process's heat, randomness, and spontaneity were assessed. The pHzpc of the SH adsorbent was 6.2, and the FTIR spectra displayed typical peaks representing functional groups that are essential for adsorption. The Sear’s surface area of SH was 77.40 m2 g-1. The most favourable conditions for the highest adsorption were achieved at the pH of 10, adsorbent dose of 5 mg, phenol initial concentration of 70 mg L-1, and temperature of 55 oC. The adsorption equilibrium was described well by the Freundlich model, while the description of the kinetics was done better by the pseudo-second-order model. The thermodynamic assessment of the adsorption process suggested that it was endothermic, random, and spontaneous. The proposed mechanism of adsorption was physical adsorption. This research showed that sorghum husk is an efficient adsorbent for the remediation of phenol.