Utilization of the copper recovered from waste printed circuit boards as a metal precursor for the synthesis of TiO 2 /magnetic-MOF(Cu) nanocomposite: Application in photocatalytic degradation of pesticides in aquatic solutions.

In this study, a number of leaching solutions (H ₂ SO ₄ , CuSO ₄ and NaCl) and an electrochemical method were used together for the separation of Cu from waste printed circuit boards. Secondly, the magnetic-MOF(Cu) was synthesized using the Cu recovered from waste printed circuit boards. Thereafter, TiO ₂ /mag-MOF(Cu) composite was prepared and its photocatalytic activity was assessed in the photo degradation of two prominent organophosphorus pesticides, namely malathion (MTN) and diazinon (DZN). The catalytic structure of the MOF-based composite was fully characterized by various analyses such as XRD, SEM, EDAX, FT-IR, VSM and UV-vis. The obtained analyses confirmed the successful synthesis of TiO ₂ /mag-MOF(Cu) composite. The synthesized composite exhibited highly efficient in the degradation of both pollutants under the following conditions: pH 7, contaminant concentration 1 mg/L, the catalyst dosage of 0.4 g/L, visible light intensity 75 mW/cm ² and reaction time of 45 min. First order kinetic model was best suited with the experimental results (R ² : 0.97-0.99 for different MTN and DZN concentrations). Trapping studies revealed that superoxide radicals (O ₂ ^•- ) played an important role during the degradation process. Furthermore, the catalyst demonstrated a superb recovery as well as high stability over five cyclic runs of reuse. In addition, the total organic carbon (TOC) analysis showed over 83% and 85% mineralization for MTN and DZN, respectively. The combined system of TiO ₂ /mag-MOF(Cu)/Vis also exhibited a great level of efficiency and feasibility in the treatment of tap water and treated wastewater samples. It is concluded that TiO ₂ /mag-MOF(Cu) could be used as an excellent catalyst for the photodegradation of MTN and DZN in aqueous solution.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
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