Research On Degradation Of Macromolecular Organic Pollutants In Water By Cobalt-based Catalyst/Sulfite System

Macromolecular organic compounds are commonly refractory pollutants in water,of which acetaminophen（also known as 4-acetamido phenol,paracetamol or acetaminophen,collectively referred to as APAP）is one of the typical pharmaceutical macromolecular organic pollutants.As an antipyretic and analgesic drug widely used in the world,the residue of acetaminophen in wastewater poses a great threat to human health and water environment,so the treatment of wastewater containing low concentration of acetaminophen has important environmental significance.In recent years,with the development of Advanced Oxidation Processes（AOPs）,the use of environmentally friendly catalysts has become an important means of rapid mineralization of organic pollutants.In this study,carbon molecular sieve CMK-3 was innovatively used to support transition metal Co to activate sodium sulfite,which can generate a variety of strong oxidizing free radicals and non-free radicals to degrade low concentration APAP.The main research contents and results are as follows:（1）Co/CMK-3+S（IV）system was sufficient and feasible to degrade APAP,and the degradation rate reached 90.70%after 60 min.Various parametershad effects on the degradation rate.Under neutral conditions（p H=7）,catalyst concentration of 0.6 g/L,the concentration of SO₃^2?is 10 m M,the system has the best degradation effect on the concentration of 0.010 m M APAP.（2）Combined with the characterization results of the catalyst,free radical quenching experiment,EPR detection analysis,electrochemical analysis and other technical means,it can be seen that the oxidized cobalt particles can make a sufficient electron transfer reaction between sodium sulfite and the target pollutant APAP through the special structure of carbon rod and carbon bridge.A variety of possible oxidizing substances(SO₄^·?,^·OH,¹O₂ etc.)were produced to degrade APAP;The CMK-3 carbon material itself can also be activated to produce oxidizing substances（e.g.¹O₂）;At the same time,in this process,water molecules can also be catalyzed to produce hydroxyl radical（^·OH）,thus accelerating the degradation of pollutants.（3）According to GC-MS,LC-MS/MS and other instruments,APAP generated multiple possible degradation pathways under the action of free radicals and non-free radicals,generating important intermediate products such as hydroquinone and p-benzoquinone,etc.Under the further action of each active species,it eventually generated acetic acid,CO₂ and water and other small molecular organic compounds.