Novel magnetically separable tetrahedral Ag₃PO₄/NrGO/CuFe₂O₄ photocatalyst for efficient detoxification of...

An effective as well as eco-friendly photodegradation methods by atoxic and easily reusable photocatalysts are essential for wastewater treatment. Silver phosphate (Ag₃PO₄) specifically in tetrahedral shape is one of the superior catalysts under visible light but its photocorrosion, poor electron transfer ability and low surface adsorption properties limits its applications. Combination of Ag₃PO₄ and nitrogen doped reduced graphene oxide (NrGO) having higher in surface area, ample functional groups and hetero atom doping is expected to get over the problem. Further addition of a spinel ferrite (CuFe₂O₄) could enhance the visible light response activity and helps in easy separation of catalyst for reuse. Given the merits of Ag₃PO₄, NrGO and CuFe₂O₄ we rationally integrated a novel magnetically separable stable Ag₃PO₄/NrGO/CuFe₂O₄ photocatalyst for efficient detoxification of 2,4-dichlorophenol (2,4-DCP). About 95.3% degradation efficiency was achieved by Ag₃PO₄/NrGO/CuFe₂O₄ (k = 0.01978 min^-1) which was ~2.6 times higher than pure Ag₃PO₄ (k = 0.00747 min^-1) in 60 min of visible light irradiation. The Ag₃PO₄/NrGO/CuFe₂O₄ heterojunction was able to separate and recycle easily using an external magnetic field due to its strong magnetism, and after 5 recycles it showed 88.6% of degradation efficiency revealed its higher stability and recyclability. The photocatalytic mechanism of Ag₃PO₄/NrGO/CuFe₂O₄ was explained by heterojunction energy-band theory. In addition, the plausible intermediate products of 2,4-dichlorophenol were analyzed by ESI/LC-MS and proposed the pathway. Moreover, the phytotoxicity was also studied on V. radiata in which GI (germination index) was found to be 11.97% before degradation, while 80.31% of GI was observed in 60 min of degradation which revealed that more significant reduction in toxicity was attained on this photodegradation.