Adsorption of Methylene Blue from Aqueous Solution by Humic Acid Extracted from Freshwater River Humus

The extraction and utilization of humic acid (ha) as a low cost adsorbent for the removal of methylene blue (mb) from aqueous solution was investigated. the ha extracted from the sediment of the lower course of a river gave a yield of 4.89%. characterization of the ha was performed using n2 adsorption, fourier transform infrared spectroscopy (ftir), x-ray diffraction (xrd) and ultra-violet visible spectroscopy (uv-vis). adsorption potential of the prepared ha for the removal of mb from aqueous solution was evaluated by batch method. the results revealed significant adsorption with just 100 mg of ha, suggesting a high adsorption potential. the solution ph was found to influence the adsorption behaviour of the ha, due to the overall negatively charged surface of the adsorbent at high ph. the data obtained from the equilibrium adsorption studies were fitted to langmuir, freundlich and temkin’s isotherm models. the adsorption was best described according to the freundlich’s isotherm model (r^2 = 0.971), suggesting a layer by layer adsorption. this study indicates that humic acid could form an eco-friendly low cost adsorbent for the removal of cationic dyes from aqueous solution.