Application of Photocatalytic and Adsorption Process for Residue Organic Degradation Using Doped ZnO Composites Hydrogel Beads

摘要

This research aimes to synthesize photocatalyst-sodium alginate composite hydrogel beads which apply for coupled adsorption and photocatalytic degradation of organic residue. Fe3O4, graphitic carbon nitride(g-C_3N_4), grapheme oxide(GO) and AgNO_3 doped ZnO photocatalyst composites hydrogel beads were synthesized and characterized using Fourier-transform infrared spectroscopy (FT-IR), X-ray Diffraction (XRD), and Transmission Electron Microscopy(TEM). Photocatalytic and adsorption activity are studied by Methylene blue(MB) degradation under sunshine irradiation. The effect of different parameter as photocatalyst types and reaction time were studied upon the efficiency of organic residue degradation. The coupled photocatalytic and adsorption processes were evaluated through various kinetic models such as pseudo-first-order/ pseudo-second-order in Langmuir-Hinshelwood model model, the Elovich model and the intra particle diffusion model. Kinetics studies showed that the coupled photocatalytic and adsorption processes in photodegradation of all sample was well described by the pseudo-second-order model because R2 of all sample were close to 1 which compared with another model. For photodegradation efficiency, the best choice in this condition was g-C_3N_4 doped ZnO composite hydrogel bead. Photodegradation efficiency and the pseudo second order rate constant of photocatalyst ZnO+gC_3N_4/SA composite hydrogel bead were 83.80%(for 180 min and up to 96% for 7 hr) and 5.05×10~(-3) g.mg~(-1) min~(-1), respectively.