keywords: Adsorption, Pilliostigma thonningii, methylene blue, Adsorbent, Hildegardia barteri, Perqutinia nigrescens
Pilliostigma thonningii (PSH) known as camel’s foot, monkey bread. Hildegardia barteri (HB) – Christmas tree. Perqutinia nigrescens (PNS) were used to remove methylene blue (MB) from aqueous solution which is one of the most commonly used substance for dyeing cotton, wood and silk. This dye when inhaled it is associated with injury of the eye, burning sensations, nausea, worming, profuse sweating, and mental confusion. The effects of various operating parameters such as contact time (30 to 300 min), adsorbent dosage (0.1-2 g), pH (2-8), temperature (30 -70o C) and initial concentration (10-400 mg/g) was studied. The result shows that PSH, PNS and HB were able to remove up to 99% MB at various initial dye concentration. The equilibrium data were also fitted to Temkin, Langmuir and Freundlich isotherm models. It was discovered that the data fitted well to Freundlich, R2 was 0.9092(PSH), 0.9482 (PNS) and 0.9484(HB) and Temkin R2 for PSH, PNS and HB was 0.8699, 0.8302 and 0.827 respectively. The adsorption data obtained for the three adsorbents fitted into pseudo second order kinetic model with R2 as 0.9999, 1 and 1 for PSH, PNS and HB respectively.