Improvement Of Related Advanced Oxidation Technology For High-salt Wastewater Treatment And Life Cycle Assessment

Nowadays,water resources are very scarce,and they have been valued by more and more countries around the world.Wastewater treatment,including recycling,is very important for solving the current water crisis.High salinity wastewater refers to wastewater with a salt content of more than 1%.and it is one of the currently difficult wastewaters.At present,the advanced oxidation method for treating industrial wastewater has gradually matured,and the new advanced oxidation technology is relatively time-saving and cost-effective.It has the advantages of high degradation efficiency of organic matter,wide application range,mild reaction conditions,and easy industrial application.Starting from a real high-salt wastewater treatment project,this study explored the advanced oxidation processes used in a coal chemical high-salt wastewater in western China and a high-salt wastewater in a pharmaceutical company in east China.The specific research content and results are as follows:(1)The mechanism of Fe/Al2O3 catalytic ozonation deactivation of a high-salt wastewater from a coal chemical industry in western China was investigated.It was analyzed by color density.BET,XRD,XRF,XPS,ICP-MS,Py-IR,etc.The serial characterization found that the silicate in the wastewater was the main reason for the deactivation of the Fe/Al2O3 catalyst.The DFT calculation revealed the catalyst deactivation mechanism.Silicic acid,as a relatively strong Bronsted acid,preferentially interacts with Fe-O-Al,Fe-OOH and other positions to reduce the Lewis acid abundance on the catalyst surface,which leads to Catalyst deactivation.(2)Through simple alkaline modification of spherical activated carbon,we optimized the efficiency of catalytic ozonation and calculated and compared its catalytic kinetic constant Rct.The results show that the modification temperature and lye concentration have a greater impact on the modification effect.When using 10M/L NaOH and the temperature gradient of 70? and 40?,the highest Rct value was obtained(2.17×10-6).Under neutral conditions,when the ozone speculative amount is 4 ppm and the catalyst addition amount is 250 ppm,the removal rate of p-chlorobenzoic acid exceeds 20%in 20 minutes.(3)CML2 baseline2000 was selected to perform a life cycle assessment of the homogeneous Fenton process for a high-salinity pharmaceutical wastewater produced by a chemical company along the eastern coast of China to identify environmentally sensitive processes in the Fenton process and propose optimization recommendations.It was found that in the stage with the greatest environmental impact,the infrastructure construction stage accounted for 84.4%,followed by the iron mud treatment stage at approximately 9.24%.The process operation phase is the main source of contribution to the consumption of resources,pollution of the ecological environment and damage toxicity,among which hydrogen peroxide is an environmentally sensitive factor.The disposal of iron-containing sludge in this process is also an important source of environmental impact,mainly manifested in the treatment and incineration of hazardous solid waste.