Removal of water-soluble dyes and pharmaceutical wastes by combining the photocatalytic properties of Ag3PO4 with the adsorption properties of halloysite nanotubes

摘要

Contaminated water can be best treated by a combination ofzi water treatment technologies such as photocatalysis and adsorption. A photocatalyst-adsorbent system made up of Ag3PO4 and halloysite nanotubes (HNTs) was synthesized by precipitating Ag3PO4 in the presence of dispersed HNTs. The synthesized Ag3PO4–HNTs were characterized by X-ray diffraction (XRD), Fourier transform infra-red spectroscopy (FTIR), scanning electron microscopy-energy dispersive spectroscopy (SEM-EDX), thermogravimetric analysis (TGA), and diffuse reflectance spectroscopy (DRS). The as-prepared Ag3PO4–HNTs showed high photocatalytic activity in visible light and high efficiency of adsorption for water-soluble dyes, such as methylene blue and rhodamine B, and pharmaceutical chemicals, such as diclofenac sodium, ibuprofen, flurbiprofen, naproxen sodium, and carbamazepine. The efficiency of the photocatalytic activity and the adsorption capacity of Ag3PO4–HNTs were dependent on the percentage of HNTs in the photocatalytic-adsorbent material of Ag3PO4–HNTs. The intermediate products for the photodegradation of ibuprofen and naproxen sodium were identified with liquid chromatography-mass spectrometry (LC-MS). The synthesized Ag3PO4–HNT composites showed good potential application in the treatment of polluted water. Keywords: Silver phosphate, Nano clay, Photocatalysis, Photodegradation, Water purification