Title : Loading metal phthalocyanine on modified graphene oxide for photocatalytic effect
Nowadays emission of harmful and dangerous substances which is released from various chemical industries is a major concern. Dichlorophenol (DCP), which is commonly used as herbicide, biocide and wood preservative are extremely dangerous pollutants due to its high toxicity towards all organisms. Over the past decades, different techniques for the treatment of organic-contaminated wastewaters have been applied including photocatalysis and recently, cobalt phthalocyanine (CoPc), a two-dimensional 18-π electron aromatic macrocycle with a Co atom located at the central cavity, has been intensively studied as an effective catalyst. CoPc is thermally and chemically stable, and cost-effective. 2, 4-dichlorophenol (DCP) is one of the pollutants which are regarded as a very high risk compound. The present work has attempted for degradation of this compound. For this purpose, cobalt phthalocyanine (CoPc) is immobilized on graphene oxide (GO) and on the modified graphene oxide prepared as a nitrogen-doped graphene (NG) or the reduced graphene oxide (RGO). The efficiency of these prepared photocatalyst is studied. A conventional Hummers’ method is used for the preparation of GO. NG sheets are prepared by either the thermal annealing graphene oxide using melamine (as a source of nitrogen) or a hydrothermal method using graphene oxide and ammonium carbonate (source of nitrogen). Also, RGO is synthesized using hydrazine hydrate for reduced GO. The synthesized samples are characterized by X-Ray diffraction (XRD), Fourier- Transform spectroscopy (FT-IR), Field emission scanning electron spectroscopy (FESEM), Energy dispersive X-ray (EDX), UV-Vis spectra, Raman spectroscopy, transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The degradation of DCP was tested under visible light using prepared photocatalysts. The prepared photocatalyst based on NG (synthesized by thermal annealing and using a 1:10 ratio of graphene oxide/melamine) and containing CoPc showed the highest activity. In this regard complete degradation of some DCP with a 40 ppm concentration using only 6.5 mg of CoPc/NG (1:10) has taken place within 135 min.