Study On The Synergistic Photocatalytic Degradation Of Phenolic Pollutants By T.obliquus/TiO₂ Coupling System

Microbial activity and resistance to external environmental changes were key factors affecting the biological treatment of toxic contaminants.Traditional biological treatment technologies required continuous energy input,which was contrary to the concept of low carbon water treatment and affected by pollutant toxicity.The used of solar energy by microalgae for wastewater treatment was widely recognized as environmentally friendly,green,sustainable and low cost,but how to improve the light utilization rate and adaptability to toxic pollutants was the bottleneck of microalgae water treatment at present.Inspired by the study on"Analysis of the effect of titanium dioxide nanoparticles on biotoxicity in natural water environment",this study was conducted to construct a T.obliquus/TiO₂coupled system by using the properties of biosynthetic nanomaterials with high bioadaptability and low biotoxicity.Using phenol wastewater and highly toxic o-cresol wastewater as the target pollutants,the T.obliquus/TiO₂ coupled system was investigated for the degradation of toxic pollutants and the effect on microbial activity.（1）The T.obliquus/TiO₂ coupled system had good enhancement on the removal efficiency of phenol and the biological metabolism of the system.the removal efficiency of phenol by the T.obliquus/TiO₂ coupled system was 2.30 times higher than that of the T.obliquus system.The mechanism study showed that the extracellular polymer（EPS）secretion in the T.obliquus/TiO₂ coupled system increased 9.84 times compared to the T.obliquus system,reaching 521.86 mg/g VSS,and EPS acted as an electron transfer medium;the current exchange density and capacitance of the T.obliquus/TiO₂ coupled system were increased by The current exchange density and capacitance of the T.obliquus/TiO₂ coupled system increased by 52.76μF and 3.59×10^-8 A/cm²,respectively,and the resistance decreased by 3.91Ω,which effectively improved the electron exchange rate and reduced the resistance to electron exchange;the T.obliquus/TiO₂ coupled system had low superoxide dismutase（SOD）and lipid peroxide（MDA）,which effectively reduced the generation of reactive oxygen species（ROS）and decreased the The free radical trapping experiment explored that photo-hole（h⁺）played an important role in the removal of phenol by T.obliquus/TiO₂ coupled system,which could effectively reduce the electron-hole pair recombination rate and improve the photocatalytic performance of TiO₂ photocatalytic time.The results show that the T.obliquus/TiO₂coupled system can improve the bioactivity,electrochemical properties and photocatalytic performance of TiO₂ in the system,thus significantly enhancing the removal of phenol.（2）The T.obliquus/TiO₂ coupled system showed good adaptability and removal enhancement for highly toxic o-cresol pollutants.the removal rate of o-cresol by the T.obliquus/TiO₂ coupled system was increased by 75.06%,and the biomass in the coupled system was significantly improved.The mechanism study showed that the T.obliquus/TiO₂ coupled system increased the cell membrane permeability during the degradation of o-cresol,which was beneficial to the material exchange and electron transfer;the zeta potential indicated that the T.obliquus/TiO₂ coupled system had stronger stability;meanwhile,the T.obliquus/TiO₂ coupled system improved the system electrochemical activity,electron transfer The changes in the biological properties of the T.obliquus/TiO₂coupled system indicate that the T.obliquus/TiO₂ coupled system is more stable.T.obliquus/TiO₂ coupled system was broad-spectrum and bio-friendly for the degradation of phenol-containing wastewater.This thesis investigates the performance of constructing a T.obliquus/TiO₂coupled system to synergistically enhance the adaptation to toxic pollutants and promote pollutant removal.It provides a theoretical basis for low-carbon and efficient treatment of phenol-containing toxic wastewater.