Performance On Activation Of Persulfate By Sludge Biochar Toward Degradation Of Micropollutant

With the rapid advancement of industrialization and urbanization,micro-pollutants are widely present in various water bodies,and it is difficult to remove them with conventional sewage treatment technologies.This not only seriously affects the feasibility of wastewater reuse,but also poses a major threat to human health and environmental safety.The advanced oxidation technology has shown good potential in degrading micro-pollutants.Among them,the advanced oxidation technology based on persulfate is widely used because of its high selectivity and long half-life.Carbon-based material activation has attracted widespread attention as a cost-effective persulfate activation method.In this study,a sludge biochar catalyst was prepared by the pyrolysis method which uses the surplus sludge of a municipal wastewater treatment plant as raw material,and the physical and chemical properties of the catalyst prepared at different pyrolysis temperatures were comprehensively characterized.On this basis,a sludge biochar-persulfate catalytic degradation system was constructed,and bisphenol A（BPA）was used as a model pollutant,and its catalytic performance and mechanism of action were systematically explored.The research results show that the sludge biochar SBC（500）prepared by pyrolysis at 500°C has the highest degradation efficiency of pollutants.When100 m L of bisphenol A solution with a concentration of 10 mg/L is used as the reaction solution,after 0.5 mmol/L PS is added to the system,7 mg of sludge biochar can remove the bisphenol A in the system in about 20 minutes.Completely removed.At this time,the total organic carbon（TOC）removal rate is about 80%.Compared with the single adsorption reaction of sludge biochar,its removal efficiency is doubled.At the same time,the catalytic degradation reaction process involves free radical and non-radical pathways,namely sulfate radical（SO₄·^-）,hydroxyl radical（·OH）and superoxide radical(·O^2-),as well as singlet oxygen（¹O₂）and free electrons belonging to the non-radical pathway,are involved in the removal of pollutants.Among them,the electron transfer pathway in the free radical pathway is the dominant one.In addition,this study found that the sludge biochar-persulfate system showed strong p H adaptability and anti-ion interference ability by adjusting the reaction parameters and the degradation experiments of different water substrates.At the same time,the leaching toxicity and acute biological toxicity tests show that the system has low ecotoxicity.Therefore,this highly efficient sludge biochar-persulfate catalytic system provides a new technology strategy for advanced wastewater treatment and waste utilization.