Experimental Study Of Wastewater Treatment With Solar And UV-LED Double-effect Photovoltaic And Photochemical

Energy and water crisis have become more and more serious.It will be an effective way that exploiting solar energy which is clean,abundant and renewable to tackle with energy and water problems.The solar spectrum is wide,only visible and near-infra lights can be used by crystalline silicon cell to generate electricity;And only ultraviolet can be used to photochemical wastewater treatment.Considering the difference of spectral response wavelength between photovoltaics and photochemical,we proposed a hybrid system combining photovoltaic power with wastewater treatment processes,and the electricity generated by photovoltaics is used to drive UV-LED which is efficient to enhance the degradation of pollutant.In this way,it not only make full use of the solar spectrum,deal with wastewater efficiently,but also the electricity generated by PV is used well.Based on the above design,we constructed SOL&PID system?a water purification system with solar and UV-LED powered by photovoltaics photocatalytic reactor?,SOLWAT system was constructed to have a comparative analysis with SOL&PID system in photovoltaic and photocatalytic performances.Ti O₂ particle were chosen as photocatayst to degrade Acid Red 26?AR 26?and 4-chlorophenol?4-CP?.The photocatalytic and photovoltaic performance in SOL&PID system as well as the feasibility of connection between solar cell and UV-LED were analyzed.At the same time,hydrogen peroxide?H₂O₂?and potassium persulfate?K₂S₂O₈?were chosen to replace TiO₂ to optimize flat reactor.And the configuration?wavelength and work condition of UV-LED were optimized by photocatalytic degradation AR 26.The results show that:1)The solar cell have a good match with UV-LED,more than 90%of the maximum output power generated by PV modules is used to drive the UV-LED array to emit ultraviolet light and enhance the degradation.2)The degradation of AR 26 and 4-CP in SOL&PID and SOLWAT systems follow first order kinetics.While because of the addition of UV-LED in SOL&PID system,the degradation effect in SOL&PID system is better than in SOLWAT system.The reaction rate constants with the intimal concentration 15 mg/L,20 mg/L,25 mg/L were enhanced 37%,23%,21%respectively in AR 26 experiments,and 79%,41%,31%in 4-CP experiments.3)As the experiments proceeds,the output performance of solar cell is increased in AR 26 experiments,while it does not have an obvious change in colorless 4-CP experiments.4)We used homogeneous photochemical Solar/K₂S₂O₈and Solar/H₂O₂ to replace the heterogeneous TiO₂ photocatalysis,not only the photovoltaic performance is enhanced but also the degradation of pollutant are increased.At meanwhile,Solar/K₂S₂O₈ has better degradation effect than Solar/H₂O₂.5)The two configuration of the UV-LED in this research have same degradation effect,while 385 nm UV-LED is benefit for the degradation of pollutant than 380 nm UV-LED in SOL&PID system,and the degradation of AR 26 is enhanced as the working voltage increases.