The degradation of phenol using ozone with activated carbon (O3/AC system) was investigated in this study. The O3/AC system was also compared with the single O3 and AC systems. The total organic carbon (TOC) removal efficiency in the O3/AC system was roughly 26% and 30% higher than the single AC and O3 systems, respectively. It was demonstrated that the phenol degradation rate and TOC removal efficiency were significantly affected by the ozone concentration, AC dosage, and solution pH. The pseudo-first-order and pseudo-second-order kinetic models were fitted to identify the mechanisms of the phenol removal process. The results of Scanning Electron Microscopy, Brunauer-Emmett-Teller, and Fourier-transform infrared spectroscopy of raw and used AC indicated that the surface morphology, microstructure, and functional group properties had been changed during the reaction process. The possible O3/AC system mineralization mechanism for phenol removal was tentatively proposed using scavenging active species such as ·OH, O2⋅−, and H2O2. The transformation byproducts generated during the application of the O3/AC system were identified by High Performance Liquid Chromatography and Gas Chromatography–Mass Spectrometry analyses. Therefore, the mineralization pathway of phenol in detail was proposed in acidic (pH 3.0) and alkaline (pH 11.0) conditions. This study provided a more systematic explanation of the mineralization mechanism for phenol in the O3/AC system.

Iron- and/or manganese-supported catalysts on granular activated carbons (Fe and/or Mn/GACs) were prepared, and their catalytic activities were evaluated by using them to treat phenol and secondary petrochemical effluent via ozonation. The presence of Fe and/or Mn/GACs significantly improved the degradation and degree of phenol mineralization. Changes in dissolved ozone concentrations and the effects of carbonate and tert-butyl alcohol (TBA) indicated that the prepared catalyst enhanced the decomposition of ozone into hydroxyl radicals (·OH), which was determined to be a key factor in catalyzing the ozonation of phenol. Typical intermediate products were identified by GC-MS and HPLC analysis, and a possible degradation pathway of phenol via catalytic ozonation was proposed. The results of XPS, CV, and other experimental data indicated that introducing Fe and/or Mn increased the rate of ozone decomposition into ·OH, and also enhanced the interfacial electron transfer by Fe2+-Fe3+ and Mn2+-Mn3+-Mn4+ redox cycles, resulting in higher catalytic activity. However, the Fe-Mn/GAC surface was shown to undergo galvanic corrosion between Fe3O4 and MnO2, decreasing the catalytic activity. In addition, catalytic ozonation was used to treat secondary petrochemical effluent. The results demonstrated that the Mn/GAC/O3 system significantly improved the quality of phenol-containing wastewater in terms of its COD, TOC, NH4+-N, water color, and ecotoxicity. This study gives a better understanding of the phenol treatment by catalytic ozonation using Fe and/or Mn/GAC.

Coking wastewater is the wastewater produced from coal coking process,and contains highly concentrated organic pollutants, such as phenols, benzene and its derivatives, heterocyclic compounds and polycyclic compounds,etc. It also contains high salinity and high ammonia nitrogen. These characteristics make coking wastewater a kind of refractory industrial wastewater. Since the management of coking wastewater becomes strict day by day,the traditional pretreatment plus biological treatment process cannot meet the requirements for its discharge or reuse. Therefore,the advanced treatment of coking wastewater is imperative. The research and application situation of the commonly used technologies for the advanced treatment of coking wastewater are introduced in two aspects:physical?chemical method and biochemical method. The future research and development direction of the advanced treatment of coking wastewater are proposed tentatively.

Chemical oxygen demand (COD),total organic carbon (TOC),biological oxygen demand (BOD),ultraviolet-visible spectroscopy (UV-VIS),high performance liquid chromatography (HPLC),gas chromatograph-mass spectrometer (GC-MS),and gel permeation chromatography (GPC) analyses were performed on wastewater sampled during the catalytic ozonation of coking wastewater in order to study the characteristics of pollutant degradation during this process.The results showed that COD,TOC,and UV254 of the wastewater were lower following the catalytic ozonation treatment,and the rates of decrease were as follows:UV254 ＞ COD ＞ TOC.The biodegradability of wastewater was improved by the catalytic ozonation treatment;however,when the ozonation time was prolonged,the biodegradability decreased.HPLC results showed that nonpolar substances were removed in preference.GPC results showed that smaller-molecular-weight substances were removed in preference.GC-MS results showed that phenols,heterocyclic compounds,polycyclic aromatic hydrocarbons,and their derivatives were the main pollutants in the coagulation effluent of coking wastewater,and these substances were effectively oxidized after catalytic ozonation.

Fenton,electro-catalytic oxidation and ozone oxidation were used in the advanced treatment of biochemical effluent of landfill leachate.The removal effect of COD and influencing factors were investigated.The results showed that the greatest removal rate of COD of biochemical effluent of landfill leachate reached 73％,58％ and 75％ treated by three kinds ofadvanced oxidation technology including Fenton,electro-catalytic oxidation and ozone oxidation.Ozone oxidation was determined as the optimal process by comparing from the aspects of the treatment results,treatment costs,difficulty level of operation,with or without secondary pollution,engineering application feasibility.

A Pilot study on advanced treatment of wastewater produced by pressurized coarse coal gasification was done in a coal chemical plant. The feasibility of catalytic ozonation, UV/O-3, and Fenton process in the advanced treatment of wastewater produced by pressurized coarse coal gasification process was studied and catalytic ozonation was proved to be a good choice with high COD removal (55%). Furthermore, a two-stage advanced treatment process combined with advanced oxidation processes (AOPs) and biological aerated filter (BAF) was proposed to meet the requirement of ultrafiltration-reverse osmosis (UF-RO) wastewater reuse system. It was found that catalytic ozonation showed the advantage in the first stage oxidation while UV/O-3 process showed the advantage in the second stage oxidation. Ultimately, we developed the interesting catalytic ozonation-BAF-UV/O-3-BAF process and the effluent met the UF-RO requirement of COD<50 mg/L, which opened a new and efficient channel for pressurized coarse coal gasification wastewater treatment.

高级氧化技术在处理难降解工业废水方面具有独特的优势,如反应速度快、有机物降解彻底、无二次污染、水质适用范围广等,可以大大提高难降解工业废水的可生化性,将难降解的有机物分解,因此近年来受到业界的广泛关注.详细归纳、总结了近年来国内外采用Fenton法、电催化氧化法、臭氧氧化法、湿式氧化法、超临界水氧化法等高级氧化技术处理高浓度难降解工业废水的研究进展,并从反应机理、处理成本、处理效果、操作难易程度、工程应用可行性等方面对多种高级氧化技术进行比较,以期为高级氧化技术在难降解工业废水处理中的应用提供参考.

Ozonation of oxalate in aqueous phase was performed with a commercial activated carbon (AC) in this work. The effect of AC dosage and solution pH on the contribution of hydroxyl radicals (HO) in bulk solution and oxidation on the AC surface to the removal of oxalate was studied. We found that the removal of oxalate was reduced by tert-butyl alcohol (tBA) with low dosages of AC, while it was hardly affected by tBA when the AC dosage was greater than 0.3g/L. tBA also inhibited ozone decomposition when the AC dosage was no more than 0.05g/L, but it did not work when the AC dosage was no less than 0.1g/L. These observations indicate that HO in bulk solution and oxidation on the AC surface both contribute to the removal of oxalate. HO oxidation in bulk solution is significant when the dosage of AC is low, whereas surface oxidation is dominant when the dosage of AC is high. The oxalate removal decreased with increasing pH of the solution with an AC dosage of 0.5g/L. The degradation of oxalate occurs mainly through surface oxidation in acid and neutral solution, but through HO oxidation in basic bulk solution. A mechanism involving both HO oxidation in bulk solution and surface oxidation was proposed for AC enhanced ozonation of oxalate.

A commercial activated carbon (AC) was modified with a nitration or amination method, and the effects of textural and chemical properties on the ability of the AC samples to destroy oxalic acid (OA) using ozone was investigated in this work. The degradation rates of OA on the nitrated and aminated AC samples increased by 38.5% and 9.6%, respectively. The adsorption capacity of the AC sample was not enhanced after modification, but the decomposition rate of ozone in solution increased. The surface area of AC significantly decreased after nitration because the entrance of micropores and some larger pores were blocked by the modified functional groups. In addition, the surface area was recovered when the nitrated AC was further aminated. We demonstrated that the enhancement in the catalytic activity was primarily caused by the differences in surface chemistry. The pH(pzc) values and Boehm titration results showed that nitration increased the acidity of the AC, while more basic groups were grafted after amination. X-ray photoelectron spectroscopy (XPS) and temperature programmed desorption (TPD) results confirmed that-NO2 and acid oxygenated groups were simultaneously grafted onto AC during nitration. Meanwhile, the-NO2 group was completely reduced to-NH2 and the carboxylic groups were partially reduced during amination. The basic groups (-NH2 and possible pyrone groups) enhanced the catalytic activity of the aminated AC sample, and the increased activity of the nitrated AC material was mainly due to the acid oxygenated surface groups. (C) 2013 Elsevier B.V. All rights reserved.