Degradation Of The Organic Pollutants In Aqueous Solution Based On Sulfate Radicals

Over the past years, the promising sulfate radicals (SO₄^·-)-based advanced oxidationprocesses （SR-AOPs） not only have gained popularity due to their high oxidative capacity andapplicability to a wide pH range but have been recognized as the effective and excellentmethods for the degradation of hazardous, refractory and non-biodegradable organicpollutants in various types of water. The influencing factors, the reaction kinetics and reactionmechanism of homogeneous Co²⁺/Oxone、Co²⁺/US/Oxone, heterogeneous Co₃O₄/Oxone、Co_XFe_3-XO₄/Oxone、GO-Co_XFe_3-XO₄/Oxone oxidation system for the degradation of thetypical antibiotics amoxicillin pollutants and rhodamine B are investigated in-depth. Thefollowing work have been carried out:（1） The degradation of antibiotic amoxicillin wastewater induced by Co²⁺/Oxone andCo²⁺/US/Oxone system was investigated. The results showed that the ultrasonication （US）play an important role on promoting the generation of SO₄^·-. On the other hand, the increaseof temperature, ultrasonic power, catalyst concentration and oxidant concentration, thedecrease of the initial concentration of wastewater were conducive to the CODcr degradationof amoxicillin wastewater and the degradation reaction of amoxicillin follows the first-orderkinetics.（2） The degradation reaction of rhodamine B dye wastewater was conducted in theOxone solution which was activated by Co₃O₄nanocatalyst. Co₃O₄nanoparticles wasprepared by the solvothermal method and characterized by SEM, XRD and the averageparticle size was13nm. The effects of reaction temperature, pH, the amount of catalyst andoxidant and the initial concentration of wastewater for the rhodamine B degradation rate werestudied.（3） The performances of the coupling of Fe₃O₄nanoparticles with a suitable amount ofcobalt ions which was prepared by the hydrothermal method and characterized by TEM, XRD.The presence of cobalt ions in the magnetite structure strongly favored the Rhodamine Bdecomposition and the reaction rate increased with the increase of cobalt content. The optimalcatalyst was Co_XFe_3-XO₄（x=0.75） because it was easy to recover due to its uniqueferromagnetic nature and possessed suppressed Co leaching properties due to strong Fe-Co interaction. Moreover, the optimal operating parameters was investigated inCo_XFe_3-XO₄/Oxone system and the experimental results showed that weakly acidic pH, highertemperature, the increase of the amount of catalyst and oxidant, the decrease of the initialconcentration were conducive to the degradation reactions.（4） Graphene oxide （GO） was explored as the carrier of Co_XFe_3-XO₄nanoparticals owingto its adsorption and catalytic properties. The performance of GO-Co_XFe_3-XO₄which wasapplied to activate Oxone and remove rhodamine B dye wastewater was investigated. Themorphologies of GO-Co_XFe_3-XO₄were characterized by SEM, XRD and the average particlesize of nanoparticles was21nm. The effect of different cobalt content of the catalytic wascompared and reaction temperature, the dosage of catalyst and oxidant and the initialconcentration of wastewater were discussed. Furthermore, dominating reactive radicals （SO4-, OH） responsible for the degradation process were identified by quenching studies using twodifferent kinds of reagents.