A study of kinetics and thermodynamics of methylene blue adsorption onto the Yellow River bottom sediment

In this paper, the adsorption process and kinetics of methylene blue onto the Yellow River bottom sediment was investigated. It was found that the equilibrium data fitted well to the Langmuir, Freundlich, Toth and Redlich-Peterson model, with the Langmuir model showing the best fitting result compared to others. The adsorption process attained equilibrium within 60min, and the adsorption capacity of Yellow River sediment increased with the increase in adsorbent concentration, temperature, and NaNO3 concentration. The adsorption capacity of the Yellow River sediment increases as the adsorbent pH decreases to a certain value and further decreasing the pH value can lead to decreasing adsorption capacity. Moreover, the presence of humic acid in natural concentration range had a minor influence on the adsorption quantity of the Yellow River sediment. Therefore, the Yellow River sediment, an easily available material, can be used for methylene blue removal in wastewater treatment processes.