Photodegradation of organic pollutants in wastewater with different morphologies of silver phosphate nanocatalysts

Photocatalyst can use the sunlight to photodegrade the environmental pollutants. In this article, AgNO3 and Na2HPO4 were used as raw materials to prepare different morphology Ag3PO4 nanocatalyst with different methods. They are solid phase method, hydrothermal method, conversion precipitation method and direct precipitation method. Four kinds of photocatalysts are donated as Ag3PO4-GX, Ag3PO4-SR, Ag3PO4-ZJ and Ag3PO4-ZH, respectively. The obtained materials were characterized by XRD, UV-VIS DRS, SEM and BET.XRD analyse results showed that the Ag3PO4 prepared by four methods have good crystallinity form sharp diffraction peak. UV-VIS DRS results showed that the band gap of four samples are 1.66 eV (Ag3PO4-GX), 1.91eV (Ag3PO4-ZJ), 2.13 eV (Ag3PO4-ZH) and 3.37 eV (Ag3PO4-SR), respectively. SEM results showed that the samples prepared by direct precipitation method and hydrothermal method make Ag3PO4 particles more uniform and the samples have better morphology, more porous and uniform distribution of particles. The surface area of the samples prepared by the four methods is in the range of 20-35 m2/g. The photocatalytic capacity of four Ag3PO4 were investigates by methyl orange, methyl blue and ofloxacin. The photodegradation experiment showed that the Ag3PO4 photocatalyst prepared by direct precipitation method exhibited best degradation efficiency under the visible light irradiation. The mechanism of the remarkable photocatalysis was also explored by determining the role of active radicals. The results showed that h+ was the main active oxidation species in the presence of aerobic degradation of levofloxacin, while ⋅OH active species had little effect on the degradation of pollutants.