Research On Degradation Of Refractory Organics In Heterogeneous Fenton System With Au-Fe₃O₄as Catalyst

The Fenton system belonging to AOPs is catching more attention and beingwidely applied by virtue of many advantages as high reaction rate,completelyoxidation and easy accessibility.However,traditional Fenton system is facing barriersin practical application dealing with organic pollutant,such as production of ironsludge which is in huge amount and difficult to remove, extravagant consumption ofoxidant and waste of catalyst.Therefore,a new type of Fenton system inheriting theadvantages of traditional Fenton technology and avoiding the defaults mentionedabove is in urgent need.Hence in this research a new kind of gold loaded ferroferricoxide catalyst in nanoscale was prepared and applied in heterogen eous Fenton systemdeteriorating organic contaminat in order to study its treatment effect,reactiondiscipline and its reaction mechanism.In this research gold loaded ferroferric oxide catalyst Au-Fe₃O₄was synthetizedco-precipitatedly.Results of XRD,BET and VSM tests gave information on phasecomposition,average surface area and mean pore size,declaring a soundferromagnetic property which make catalyst recycle easily achieved by an appliedmagnetic field. Catalysts with different ratios of gold were tested respectively fortheir catalytic activity and Au（1.0wt%）/Fe₃O₄was selected as the most effectivecatalyst.To inspect the catalytic activity for deterioration of non-biodegradable organicpollutants,this catalyst was implemented in heterogeneous Fenton system. P-Nitrophenol（PNP）, was chosen to be the target substrate.A series of tests wasproceeded,results of which indicated that the existence of gold could significantlyenhance the heterogeneous Fenton process concerning about more than90%PNPdegradation in30min and better than65%TOC removal in90min. After that theeffects of several reaction conditions on catalytic efficiency were studied bycorresponding experiments one after another.Experimental results demonstrated thatlower pH benefits PNP degradation more except for the too acid environment as pHreaches2.0;PNP removal got better as H₂O₂concentration went up in certain limitsand deteriorated when H₂O₂concentration was way too high,the best PNPdegradation was achieved when molar ration of H₂O₂:PNP was20:1; desirable resultswere shown when initial PNP concentration varying from1.0mg/L to200.0mg/L,turned out the process is efficient in dealing with organic wastewater indifferent concentrations;experiments on Rhodamine B degradation was proceededand desirable results was presented; experimental studies declared the catalyst waseffective for a5times successive experiments and sound results of metal leaching under a range of acid circumstances; in addition we proceeded certain experimentsendeavouring to explain the mechanism of this heterogeneous Fenton system.Thisresearch sufficiently confirmed that the Au-Fe₃O₄involved heterogeneous Fentonsystem purchased many advantages as high reaction rate,completelyoxidation,recoverable catalysts and efficient in dealing with a range oforganics,hence Au-Fe₃O₄posessed high application value.