Degradation Of Tetracycline In Water By Activated PMS With Sludge-Pine Needle Derived Biochar/Metal Composite Catalyst

Advanced oxidation process（SR-AOPs）based on sulfate radical has the advantages of long half-life and high redox potential for the removal of refractory antibiotics.In SR-AOPs,metal or metal oxide nanocatellates（MNPs）are often used to activate peroxynomosulfate（PMS）.However,MNPs tend to accumulate in water,reducing the exposed active sites,and powdered MNPs are difficult to separate and recover from water.Biochar with high carbon content,large cation exchange capacity and large specific surface area can solve this problem.Based on this,this paper grasped the concept of effective utilization of waste resources,and prepared the sludge-pine needles of biochar loaded metal composite catalyst.Combined with a variety of characterization testing,the morphology,structure,performance,mechanism and process of tetracycline（TC）removal by activated PMS were systematically analyzed.The specific research contents and results were as follows.（1）Preparation and performance study of CoFe₂O₄/BC compositesA new catalyst CoFe₂O₄/BC was prepared by hydrothermal method,which not only effectively utilized waste,but also reduced the aggregation of CoFe₂O₄ and greatly improved its catalytic performance.Taking TC as the target pollutant,CoFe₂O₄/BC was used to activate PMS to degrade TC.It was found that under the best reaction condition,CoFe₂O₄/BC+PMS system showed excellent degradation performance,and the degradation efficiency of TC was up to 99.8%within 30 min.After 5 cycles,the structure and physical and chemical properties of CoFe₂O₄/BC remained stable,and the degradation efficiency of TC was still up to 96.39%within30 min.In addition,the catalytic system also showed good degradation performance for other antibiotics.It was found that SO₄^·-and HO^·formed during the catalytic activation of PMS played an important role in the process of TC removal by radical quenching and EPR test.Based on the above analysis,the mechanism of TC removal by catalytic activation of PMS was proposed.（2）Preparation and performance study of waste ore/BC compositesA more environmentally friendly catalyst waste ore/BC was prepared by co-pyrolysis,and its raw materials were all from waste.The catalyst waste ore/BC had large specific surface area and stable structure.The waste ore/BC was used in advanced oxidation process to activate PMS and degrade TC.It was found that it had good catalytic performance.The degradation efficiency of TC was up to 95.98%within 60 min.After 5 cycles,the structure and physicochemical properties of waste ore/BC remained stable,and the degradation efficiency of TC was still up to 92.55%within 60 min.In addition,the catalytic system had good universality and good degradation performance for other kinds of antibiotics.The main active substances of TC degradation in waste ore/BC+PMS system were SO₄^·-and HO^·.The degradation mechanism of this catalytic system was proposed.（3）Research on biochar/metal composite catalyst applied in micro-experimental deviceA micro-experimental device was successfully built.After applying the CoFe₂O₄/BC+PMS system and the waste ore/BC+PMS system to the micro-experimental device,it was found that both systems had excellent effects on high-concentration TC（100 mg/L）simulated pharmaceutical and antibiotic wastewater.The degradation performance of TC could make the characteristic absorption peak of TC disappear,and the composite material could be recycled,and the built micro test device was also operable,which provided theoretical guidance for the degradation of antibiotic wastewater in practical engineering.