Kinetic Studies of Bio-sorption of Cyanide Ions from Aqueous Solution Using Carbon Black Developed from Shea Butter Seed Husk as an Adsorbent

Abstract

This research work was conducted in order to investigate the adsorption of cyanide ions by carbon black developed from Shea Butter Seed Husk (SBSH) an eco-friendly bio-adsorbent. The experiments were carried out in batch reactors with optimum operating parameters at 100 mg/l for the initial cyanide concentration, Temperature 30±2ºC, pH value 10, Adsorbent Dosage (3.0 mg/100 ml) and Contact Time of 120 minutes with maximum percentage cyanide ion removal at 94.56%. The values for the amount of cyanide ions adsorbed at equilibrium (qe) and amount adsorbed at a given time (qt) of the experimental results were fitted to the Langmuir, Halsey – Taylor (Freundlich), Henry and Slygin – Frumkin (Temkin) isotherm models with Henry Adsorption Isotherm having R2=0.966, hence, best described the equilibrium model. Adsorption of cyanide ions by SBSH Carbon Black obeyed the Pseudo-Second Order Model rate equation with the values of Coefficient of Determination; R2=0.999. Qe=3.257(mg/g) and k2=0.093(g/mg/min). Therefore, it was observed that Pseudo-Second Order Model was the best applicable model which described the bio-sorption of cyanide ions by SBSH Carbon Black, making Pseudo Second order kinetic reaction the rate limiting step for the batch reaction process.