Preparation Of Cinder And Waste Printed Circuit Board-based Photocatalyst And Study On Its Wastewater Treatment Performance

Heavy metal ion Cr（VI）and organic dye wastewater have serious harm to the ecological environment and human health.As a green,efficient and economical wastewater treatment method,photocatalytic technology has immeasurable prospects in the field of environmental remediation.Compared with traditional commercial catalysts,solid wastes such as cinder and waste printed circuit boards have the advantages of wide sources and low prices,and they can be potential photocatalyst precursors.Therefore,this study was devoted to the combination of wastewater treatment and solid waste resource utilization,and explored the application potential of modified cinder and modified waste printed circuit boards in Cr（VI）reduction and Rh B degradation.Through a series of characterization methods,the chemical composition,morphology and structure of the solid waste-based catalyst were analyzed.The wastewater treatment performance of this research system was investigated in detail,and the synergistic mechanism involved was fully revealed.The specific research contents and main conclusions are as follows:（1）Construction of the modified cinder/tartaric acid/visible light system（γ-Al@Fe/TA/Vis）and its efficient reduction of Cr（VI）.Using raw cinder as the precursor,γ-Al@Fe was prepared by means of acid hydrolysis treatment and hydrothermal synthesis.The properties of the samples were analyzed by means of XRD,XPS and SEM.By comparison,it is found that the catalyst and tartaric acid have efficient synergy under visible light irradiation,and the reduction efficiency of Cr（VI）can reach 100%within 7 min.Comparingγ-Al@Fe with commercial materials such as Fe₃O₄,it is found that theγ-Al@Fe has the best catalytic effect.Taking three real water bodies such as Xiangjiang River as the water background matrix,the remediation effect of this research system on Cr（VI）-containing wastewater was explored,and the removal efficiency could reach 100%within 15 min.5 rounds of cycle experiments and changes in properties of the catalyst after use and ion leaching conditions prove that the catalyst has excellent cycle stability.Based on the above experiments and characterization analysis,the synergistic reaction mechanism of the constructed photocatalytic system was finally obtained:tartaric acid,as a hole sacrificial agent,can effectively improve the separation efficiency of photogenerated carriers after capturing h⁺,and generate strong reducing active species CO₂·^━.The action of dissolved O₂and photogenerated electrons will produce O₂·^━.Cr（VI）is reduced to Cr（Ⅲ）under the combined action of CO₂·^━and O₂·^━.After the catalyst adsorbs tartaric acid,a photocatalytic intermediate is formed,which can effectively shorten the migration distance of electrons.Fe can act as an electron transfer medium,which can speed up the photocatalytic reaction rate.（2）Construction of modified waste printed circuit board/persulfate/visible light（Cat₁/PMS/Vis）system and its efficient degradation of Rh B.The waste printed circuit board-based catalysts were synthesized by pyrolysis,acid leaching and recombination methods from waste printed circuit board.The samples were systematically analyzed by a series of characterization techniques,and it was found that the catalyst wsa mainly composed of Cu O and activated carbon.By comparison,it is found that the degradation rate of Rh B by the Cat₁/PMS/Vis system was about 5 times that of the Cat₁/PMS or PMS/Vis system,and the complete degradation of 20 mg/L Rh B can be achieved within 20 min,which proves that the catalyst can effectively activate PMS under the synergy of visible light.It is found that the degradation of Rh B was hardly affected by common anions and humic acids in industrial wastewater,and it still had a excellent degradation effect in real water bodies such as Taozi Lake.The results of cycle experiments and the degradation test of six organic compounds showed that the Cat₁/PMS/Vis system had good cycle stability and practicability in the treatment of organic wastewater.Based on the above experiments and characterization analysis,the synergistic reaction mechanism of this system was finally revealed:PMS,as an electron sacrificial agent,can effectively improve the separation efficiency of photogenerated carriers.After capturing photogenerated electrons,PMS is effectively activated and generates radicals such as SO₄·^━and·OH.In addition,activated carbon and Cu O can also activate PMS to generate active species.In this research system,Rh B was effectively degraded under the action of SO₄·^━,·OH,O₂·^━and ¹O₂.