Study on Adsorption of HA on TiO2 Film from Aqueous Solution

Humic acid (HA) was considered to be the main precursor of disinfection by-products (DBPs) in chlorination. In this study, an effective and economic method of preparing TiO₂ film was successfully developed for adsorption of HA. The crystal structure and surface morphology of the TiO₂ film were characterized by X-ray diffraction (XRD) and atomic force microscopy (AFM). The effects of some factors such as the temperature, pH value of the solution, and initial concentration of HA on the extent of HA adsorption from aqueous solution were systematically investigated. The analytical results showed that the adsorption of HA was enhanced on the film at low temperature under acidic condition. The adsorption efficiency increased with increasing initial concentration, bias voltage and the area of the TiO₂ film. The adsorptive thermoisopleth curve of HA on TiO₂ film can be fitted by Freundlich thermoisopleth adsorption equation. The adsorption reaction complied with Lagergren second-order adsorptive kinetics model.