ELECTROPHOTOCATALYTIC PROCESS FOR REMOVING ACID HUMIC FROM AQUOUCE

Humic substances, as precursor to disinfection by-products (DBPs), are produced by the microbial degradation of dead plant matter. The goal of this research is to investigate of humic acid (HA) from urban drinking water by batch electrophotocatalytic reactor (EPC) with using zinc oxide (ZnO) nanoparticles immobilized on zinc (Zn) sheet-copper electrode, and lamp emitting dynode (LED) ultraviolet-A (UV-A) lamp. Various operating variables are tested; these included current density, initial concentration of HA, lamp intensity, layering of ZnO nanoparticles, pH, and radiation time.To prepare the ZnO films on the Zn electrode, dry methods are used. The sample is prepared by adding 5-15 milligrams of HA per ml of deionized water. The studied variables are pH (4-10), the HA concentration (5-15 mg/L), the lamp intensity (360-600 mW/cm2), radiation time (7.5-22.5 min), layering of zinc oxide nanoparticles (1-3), and current density (3-9 mA/cm2). The HA concentration is measured by using spectrophotometer at a wavelength of 253.7 nm. The optimal removal (0) is obtained at pH 4, radiation time of 15 minutes, 2- layer of ZnO nanoparticles, lamp density 600 mw/cm2, and current density of 9 mA/cm2. The HA decay follows a first order reaction. The results of HA removal efficiency by Taguchi model indicates that the reaction time is the most important variable. The electrochemical (E) process is the least efficiency. The rate of decay decreases at higher concentrations. Thus, batch experiments show that the EPC reactor could be considered as a promising technology for treating HA-polluted water.

Keywords:

Aqueous water , Electrophotocatalytic , Humic acid , Taguchi model , Zinc oxide