Preparation And Properties Of Non-Homogeneous Fenton Materials Based On Chloromethyl-Styrene Resin Loading

As a result of the development of human society and the process of industrial globalization,the problem of environmental pollution has become the focus of extensive attention of researchers.In the process of remediating the pollution of the entire environmental system,the management of water pollution problems is an extremely important part.Water is essential for the survival and development of all living things on earth,and human beings cannot survive without fresh water resources.However,the fresh water resources on earth are very limited,and some of the water sources are also quite seriously polluted.Therefore,finding a more scientific and efficient water treatment technology and applying it to the field of water environmental protection and remediation will have a crucial impact on the scientific deployment and sustainable development of water resources in the future.Antibiotics are widely used in the development of pharmaceutical,agricultural,animal husbandry and food industries.Tetracycline is a broad-spectrum antibiotic that is very stable in aqueous solutions and is capable of causing cumulative damage to the internal organs and endocrine systems of humans and animals.If ingested for a long time,it can cause harmful symptoms such as kidney failure,liver toxicity,gastrointestinal reactions and cellular resistance.Therefore,how to effectively remove tetracyclines from the aqueous environment has become a hot research topic.As most tetracyclines have conjugated double bonded quaternary dense ring structure,it is difficult to decompose them effectively by conventional technical means.advanced oxidation techniques（AOPs）in Fenton reaction are the most studied chemical methods that can effectively treat difficult to degrade macromolecular organic pollutants,and the hydroxyl radicals（HO·）generated by catalytic strong oxidants during the reaction play a key role in degradation.Among many AOPs,the method of non-homogeneous Fenton-type reaction is favored by researchers because of its low toxicity,low cost and significant degradation effect.Polymer resin materials are widely used because of their easy functionalization modification,stable physical and chemical properties and adaptability to acid and alkaline environments.Therefore,in this study,two non-homogeneous Fenton catalysts with chloromethylstyrene resin as the carrier were designed and synthesized using a suitable method and applied to a non-homogeneous Fenton system for the degradation of tetracycline（TC）organic wastewater,involving the following main studies:1.Preparation of PS-NH₂@CoMOF self-assembled materials and their study in non-homogeneous Fenton type systemsPS-NH₂@CoMOF self-assembled composites with good dispersion and uniform particle size were prepared by the cyclic loading method of self-assembled Co-MOF using chloromethyl styrene resin（PS-Cl）as the carrier and Co-MOF as the metal active site.The PS-NH₂@CoMOF catalysts were characterized by specific surface area analysis,X-ray powder diffraction,X-ray photoelectron spectroscopy and scanning electron microscopy;then the constructed PS-NH₂@CoMOF catalysts were used for the degradation and removal of tetracycline（TC）in a non-homogeneous Fenton like system combined with the strong oxidant H₂O₂.The PS-NH₂@CoMOF catalyst can remove TC up to 84.96%within 2 hours.In addition,the PS-NH₂@CoMOF catalyst was still more effective for TC degradation after eight times of recycling and reuse.The results indicate that the self-assembled structure of Co-MOF layers loaded using modified resin has excellent catalytic performance.In addition,the self-assembled composite（PS-NH₂@CoMOF）constructed by combining resin carrier（PS-Cl）also has high stability and adaptability to aqueous environment.Thus,it can be seen that PS-NH₂@CoMOF catalysts have potential applications in the field of environmental pollution control.2.Preparation of PS-NH₂@Fe Se₂material and its study in non-homogeneous Fenton like systemA new composite material PS-NH₂@Fe Se₂with core-shell structure was synthesized by hydrothermal method using chloromethyl styrene resin（PS-Cl）as the carrier and Fe Se₂as the metal active site.The PS-NH₂@Fe Se₂catalyst were characterized by a series of means such as specific surface area analysis,X-ray powder diffraction,X-ray photoelectron spectroscopy and scanning electron microscopy;then the catalytic degradation of higher concentration of tetracycline solution was carried out with the peroxynitrite system,and satisfactory catalytic effects were achieved.The removal efficiency was as high as 85.94%within 2 h,and the degradation rate constant was 0.02352 min^-1.The main advantages of the PS-NH₂@Fe Se₂catalyst were high stability and recyclability.Thus,the catalyst would not cause secondary pollution to the environment and could still achieve a degradation efficiency of nearly 70%for TC after five times of reuse.The possible catalytic degradation pathways and potential removal mechanisms were investigated through free-radical quenching experiments and HPLC-MS detection of intermediates generated by catalytic degradation.Column experiments were conducted to investigate the effect of the catalyst on the actual removal of wastewater.a simple flow model was developed using the Yellow River water to make the integration of theory and practice possible.In conclusion,the new idea constructed with Fe Se₂-loaded modified resin offers promising prospects in the removal of refractory organic compounds,such as tetracycline.