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Research On Catalysis Of CuO-CeO2Binary Mixed Oxides For PMS Degradation Of Phenol

Posted on:2014-06-15Degree:MasterType:Thesis
Country:ChinaCandidate:D W ZhangFull Text:PDF
GTID:2181330422990522Subject:Environmental Science and Engineering
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With the improve of advanced oxidation technology, based on sulfate radicaltechnological has drawn wide attention. Therefore, the development of othertransition metal heterogeneous catalysis PMS come into our vision. Due to itssynergy that mixed oxides in catalysis normally present concern. Copper is a widelyused transition metal, while cerium is also commonly used as additives in catalyticreactions, so we use binary mixture CuO-CeO2catalyse PMS, to expand a newdirection in sulfate radical advanced oxidation technology.In this paper, the CeO2supports were synthesized by so-gel autocombustionmethod and calcination method, then the supports were further impregnated usingCu(NO3)2·2.5H2O as precursor (Incipient Wetness Impregnation, IWI, method).We investigated the structure of CuO-CeO2, and its catalytic effect of PMS which asoxidant in the degradation of target pollutants phenol. We also studied the effect ofmajor process variables, such as preparation conditions and reaction conditions.Study the mixed oxides which its supports were synthesized by calcinationmethod, we use X-ray diffraction(XRD)and scanning electron microscopy(SEM)for structural characterization; Preliminary experiments about the catalysis showCuO-CeO2has a synergistic effect, significantly accelerated decomposition of PMSand improve the rate of removal of phenol. The degradation efficiency of phenolwas42.4%in5min with CuO-CeO2as catalysis,while its in60min with CuO ascatalysis.The preparation conditions and reaction conditions were studied, optimalconditions for prepariation were as follows: calcination temperature300℃,calcination time2h,30%loading; the reaction conditions are chosen as roomtemperature, pH=7, phenol50ppm, PMS1mM, CuO-CeO21g/l, the degradationefficiency of phenol reached51%; the catalyst can be reused four times and thecatalytic effect only slightly decreased by5%.Study the mixed oxides which its supports were synthesized by sol-gel method,and also use XRD and SEM for characterization. The preliminary degradationexperiments found that CuO-CeO2whose supports prepared by sol-gel had strongersynergy than that by calcination method. Reaction in30min, phenol was basicallyremoved, higher than CuO/PMS system nearly60%; Study the effect of preparationconditions and the reaction conditions, select the preparation conditions: calcinedtemperature300℃, calcined time2h,50%loading; reaction conditions were asfollows: room temperature, pH=7, phenol50ppm, PMS0.75mM, CuO1g/l; the degration of phenol was100%; reuse the catalysts for four times and the degrationwere basely stable.Analysis the mechanism of CuO-CeO2by HR-TEM and XPS. These resultsprovide unambiguous evidence of existence of redox equilibrium of Ce3+/Ce4+andCu2+/Cu+, making the CuO-CeO2in the preparation process has formed a certainamount of Cu+, and directly came into the key step, to active PMS produce SO4,thereby enhancing the catalytic performance.
Keywords/Search Tags:sulfate radicals, peroxymonosulphate, CuO-CeO2binary mixed oxides, phenol
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