Catalytic Ozonation Of Organic Pollutants With Sludge-based Carbon Materials

In recent years,with the growing output of sludge and the increase of harmful components in sewage,it has become a worldwide problem to find a stable and harmless sludge disposal scheme to turn sludge into resource.It is an effective method to roast sludge to prepare carbon-based functional materials.The catalytic ozonation performance of sludge-based carbon and its modified catalysts was studied in this paper.XRD,XPS,SEM,TGA-DSC,BET,p H_PZC and other analytical methods were operated to characterize sludge-based carbon,demineralized sludge-based carbon and pre-ozonized sludge-based carbon.Adsorption and ozonation experiments were operated for these carbon materials,too.Then,the effects of p H,ozone and catalyst dosage on the catalytic performance were investigated.According to the New R_ct Model,ozone experiments under different concentration of TBA were operated to obtain the rate constants of carbon materials in terms of direct ozone reaction（k _D）,promotion（k _P）,initiation（k _I）and inhibition（k _S）.And a kinetic model of catalytic oxidation of ibuprofen by sludge-based carbon was established by using the New R_ct Model.The results show that sludge-based carbon contain a variety of elements such as C,O,Si,Al and Fe,and many oxygen-containing functional groups such as hydroxyl and carbonyl groups are detected on the surface.After the removal of minerals,the impurities were mostly removed,the proportion of C was greatly increased,and the p H_PZC decreased.According to the ozonation experiments results,the DEA degradation rate for single ozone process,catalytic ozone process with sludge-based carbon and demineralized sludge-based carbon were 59%90%and 97%respectively.The pre-ozonation process for 20 mins decreased the catalytic performance.The portion of carbon has been improved after demineralized,ultimately affecting the rates of catalyst reacting with ozone and free radicals.The model fitted well with the actual degradation curve.Sludge-based carbon were further optimized by loading metal oxides.Numbers of analytical methods andozonation experiments were operated for sludge-based carbon loaded with 1.0 wt%Ce.Meanwhile,the effects of some experimental factors on the catalytic performance were investigated.And a kinetic model of catalytic oxidation of ibuprofen was established by using the New R_ct Model.The characterization results showed that Ce³⁺and Ce⁴⁺were co-existed on the surface.After the reaction,Ce⁴⁺increased while Ce³⁺decreased.The ozone experiment results showed that sludge-based carbon loaded with1.0 wt%Ce could both promote the decomposition of ozone and improve the DEA degradation rate.The fitting result was evaluated to be fairly well by comparing with the actual degradation curve.