Efficient Degradation Of Acetaminophen By Natural Iron Mineral–activated Peroxymonosulfate

Acetaminophen（APAP）,as a widely used antipyretic and analgesic drug globally,can enter the environment through biotransformation and other pathways.This not only directly affects the health of aquatic organisms but also accumulates through the food chain,thus impacting humans.The pollution caused by APAP in the environment and its effects on environmental organisms have attracted widespread attention,and researching efficient APAP treatment processes is of great significance.Advanced oxidation technologies,which involve the activation of persulfate by ferrous ions to generate sulfate radical(SO4^·–),have been extensively studied due to their low cost and environmental friendliness.This study employed three natural iron ores（siderite,pyrite,and ilmenite）containing Fe（II）as activators and combined them with peroxymonosulfate（PMS）to form an advanced oxidation system,achieving efficient degradation of APAP in the natural iron ore–PMS system.The degradation of APAP in natural iron ores–activated PMS system was explored.The effects of initial pH value,iron ores dosage,initial PMS concentration,coexisting anions,and humic acid on the degradation of APAP were investigated.The contribution of various reactive oxygen species（ROS）in the system was elucidated through electron paramagnetic resonance（ESR）and quenching experiments.The reuse performance of natural siderite for continuous degradation was also explored.In addition,the effectiveness of the natural iron ore–PMS system in degrading APAP and a series of aromatic compounds in natural water bodies was investigated.The main research content and conclusions include:The results show that the natural siderite–PMS system can effectively degrade APAP in the pH range of 2.0–9.0.The best removal performance toward APAP（96.1%）was obtained in the presence of 0.1 mmol L^–1 PMS,and 2.5 g L^–1 natural siderite at pH3.0 after 30 min of reaction.The degradation effect of APAP increases with the increase of siderite dosage.As the increases of PMS concentration,the degradation effect of APAP first increases and then decreases.The presence of coexisting anions had a negligible impact on APAP removal,while the addition of fluvic acid(0–50.0 mg L^–1)obviously inhibited APAP removal.The production of ROS was dependent on pH values.Sulfate radicals in solution(SO_4aq^·–)were proven to be the predominant reactive oxidant under acidic conditions.Under neutral and alkaline conditions,surface–bound sulfate radicals(SO_4ads^·–),surface–bound hydroxyl radicals(HO_ads^·)and high–valent iron were confirmed to be the predominant reactive oxidants.Additionally,natural siderite displayed excellent reusability at pH 7.0,and the natural siderite–PMS system can efficiently degrade APAP in sequential experiments.This system can also efficiently degrade APAP in natural water,and a series of aromatic compounds can be effectively degraded in the system.For the natural pyrite–activated PMS system,the results showed that low pH was favorable for APAP degradation.Under pH 3.0,the APAP degradation efficiency increased with an increase in pyrite dosage and initial PMS concentration.Almost complete degradation of APAP was achieved under the conditions of pH 3.0,pyrite dosage of 1.0 g L^–1,and initial PMS concentration of 0.15 mmol L^–1.Coexisting anions had a weak influence on APAP degradation in the natural pyrite–activated PMS system,while high concentrations of humic acid inhibited APAP degradation.In the system,SO₄^·–played a major role in the removal of APAP,and singlet oxygen（¹O₂）played a minor role.Both heterogeneous activation and homogeneous activation promoted the generation of ROS in the natural pyrite–activated PMS system.The sulfur species on the surface of pyrite promoted the transformation of Fe（III）to Fe（II）in the system.Under pH 3.0,pyrite showed good performance in terms of reuse,and it effectively removed APAP in five consecutive degradation experiments.The system was also effective in degrading APAP in natural water bodies and a series of aromatic compounds.For the natural ilmenite–activated PMS system,the results showed that acidic conditions were beneficial to the degradation of APAP in the system.The best removal performance toward APAP（98.8%）was obtained in the presence of 350.0μmol L^–1PMS,and 2.0 g L^–1 natural ilmenite at pH 3.0 after 30 min of reaction.SO₄^·–were the dominant oxidant responsible for APAP degradation,O₂^·–and ¹O₂ were of secondary importance.Several coexisting anions and high concentrations of fulvic acid have a slight inhibitory effect on the degradation of APAP.At pH 3.0,natural ilmenite exhibits excellent reusability,and the natural ilmenite–PMS system can efficiently degrade APAP in sequential experiments.This system can efficiently and rapidly degrade APAP in natural water.Natural ilmenite–PMS system can also effectively remove a series of benzene series compounds.In this study,the performance of three natural iron mineral–PMS systems on the degradation of APAP were investigated.Under the optimum conditions,all the natural iron ore–PMS system can efficiently degrade APAP.In the three systems,SO₄^·–played a major role in the removal of APAP.All three natural iron ore showed good performance in terms of reuse.The three systems were also effective in degrading APAP in natural water bodies and a series of aromatic compounds.The three systems have wide applicability in wastewater treatment,and also have specific application prospects in the treatment of organic pollutants containing electron–giving groups.