用Nano-TiO2/O3和Nano-TiO2/UV/O3去除腐殖酸并控制臭氧副产物的生成

采用Nano-TiO2/O3和Nano-TiO2/UV/O3进行小试实验。通过对DOC、UV254、BrO3-和甲醛进行检测分析,研究了不同体系去除腐殖酸（HA）并控制臭氧副产物生成的效果。结果表明,当HA浓度为10 mg·L-1时,Nano-TiO2/O3体系对DOC的去除主要在反应进行20 min内完成,去除率仅达12.0%左右,对UV254的去除主要发生在2 min内,去除率仅达14.5%左右;而Nano-TiO2/UV/O3体系DOC和UV254的去除率分别达32.8%和53.3%。HA的存在显著减少了Nano-TiO2/O3体系BrO3-的生成量,出水BrO3-浓度为29.00 μg·L-1,而Nano-TiO2/UV/O3体系出水BrO3-浓度为5.00 μg·L-1。研究表明,相比Nano-TiO2/O3体系,Nano-TiO2/UV/O3体系能更好地控制BrO3-生成,同时能提高对HA的去除效果,且无甲醛生成的风险。     

Enhanced ozonation degradation of atrazine in the presence of nano-ZnO: Performance, kinetics and effects

Enhanced ozonation degradation of atrazine (ATZ) with nano-ZnO (nZnO) as catalyst and the influences of the operational parameters have been investigated through semi-continuous experiments in this study. The results demonstrated that the combination of ozone (O₃) and nZnO showed an obvious synergetic effect and the ATZ degradation conformed to pseudo-first-order kinetics. An improvement of ATZ degradation efficiency by 41.8% and pseudo-first-order rate constant by more than a factor of four was obtained in the O₃/nZnO process after 5 min of reaction compared to O₃ alone. Meanwhile, the degradation efficiency of ATZ was gradually enhanced with increasing nZnO dosage and initial pH in the range from 3.0 to 8.0, and a higher amount of ATZ was degraded when the initial concentration of ATZ rose from 0.5 to 5 mg/L. Additionally, sulfate ion, chloride ion, nitrate ion and low concentrations of humic acid substances led to enhancement of the ATZ degradation. The notable decrease of ATZ removal efficiency observed in the presence of radical scavengers and the results of free radical tests indicated that OH is the dominant active radical species. The mechanism investigation demonstrated that the enhancement effect could be attributed to the introduction of nZnO, which could promote the utilization of O₃, enhance the formation of superoxide radical, and further accelerate the production of hydrogen peroxide and the generation of OH/O₂-.     

湿壁介质阻挡放电强化浮石载羟基氧化铁降解水中避蚊胺

以避蚊胺(DEET)为模型污染物,研究了湿壁介质阻挡放电(DBD)协同浮石载羟基氧化铁去除污染物的可行性.采用浸渍法制备了浮石载羟基氧化铁复合材料,并对其进行了SEM、XRF、XRD、FT-IR和BET表征.同时研究了放电电压、初始pH、催化剂投加量等参数对DEET的去除率的影响.结果表明:在DEET初始浓度为20mg...     

Activated carbon enhanced ozonation of oxalate attributed to HO. oxidation in bulk solution and surface oxidation： Effect of activated carbon dosage and pH

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（HOU） 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 0.3 g/L. tBA also inhibited ozone decomposition when the AC dosage was no more than 0.05 g/L, but it did not work when the AC dosage was no less than 0.1 g/L. These observations indicate that HOUin bulk solution and oxidation on the AC surface both contribute to the removal of oxalate. HOU 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 0.5 g/L. The degradation of oxalate occurs mainly through surface oxidation in acid and neutral solution, but through HOUoxidation in basic bulk solution. A mechanism involving both HOUoxidation in bulk solution and surface oxidation was proposed for AC enhanced ozonation of oxalate.     

臭氧催化氧化在石化废水深度处理应用中的若干问题

石化污水处理厂二级出水可生化性低,含部分有毒难降解有机物。随着GB 31571—2015《石油化学工业污染物排放标准》2015年7月1日的实施,我国石化污水处理厂迎来了一次集中处理技术升级,其大多采用以臭氧/臭氧催化氧化为核心的处理工艺建成深度处理单元,对石化污水处理厂二级出水进行深度处理使其达标排放。目前这类装置大多已运行超过2年,实际运行过程中,该技术出现了设计之初未曾考虑到的一系列问题,致使臭氧利用率不高且持续下降,治理成本逐年增高等。结合实际工程,从絮体、胶体大分子有机物、臭氧传质和催化剂4个方面对这些问题进行了系统分析,同时对臭氧催化氧化技术在石化污水处理厂二级出水处理中的发展方向进行了展望。     

再生水中色度物质的识别及其臭氧去除特性

针对我国再生水普遍存在的色度问题,以天津市某污水厂二级出水为研究对象,采用三维荧光光谱和GC/MS技术对其进行组成分析,结果表明:再生水中主要带色物质为富里酸与腐殖酸类物质,同时还存在偶氮二甲酸二乙酯、N,N-二甲基乙醇胺、苄醚、1,4-二甲基吡啶氯化物等导致再生水色度的带色有机物。在再生水的臭氧降解实验中,臭氧可有效降解再生水中的富里酸与腐植酸类物质,去除率分别达到96.5%、97.3%。臭氧对再生水的色度与CDOM(有色溶解有机物)的降解也表现出了良好的效果,2 min内去除率可分别达到93.1%、86.2%。并且在色度物质的臭氧降解过程中,臭氧的直接反应占据主导地位,而并非与·OH的间接反应。该结果对再生水臭氧氧化工艺的设计应用有现实的指导意义。     

Experimental studies on ozonation of ethylenethiourea

The experimental study on ozonation of ethylenethiourea(ETU) is conducted.The reaction of gas-phase ETU with 0.63 × 10-6 mol/L ozone is carried out in a 200-L reaction chamber.The secondary organic aerosol(SOA) resulted from the ozonation of gas-phase ETU is observed with a scanning mobility particle size(SMPS).The rapid exponential growth of SOA reveals that the atmospheric lifetime of ETU vapor towards ozone reaction is less than four days.The ozonation of dry ETU particles,ETU-contained water droplets an...     

饮用水中DBP的臭氧氧化效能与影响因素

以邻苯二甲酸二正丁酯 (DBP)为典型内分泌干扰物质的代表物 ,对饮用水中大量存在的不同物质在不同反应条件下对O3氧化DBP的影响进行了研究 .结果表明 ,O3单独作用于DBP时 ,在反应进行 30min后就能去除 90 %以上 ;O3对DBP的氧化降解除了O3的直接氧化外 ,还有·OH的作用机制 ;HCO-3 和腐殖质都通过影响·OH的产生而影响DBP的O3氧化 ,水中的浑浊度由于对疏水性的DBP会产生吸附作用而对DBP的去除有促进作用 .     

Inhibition of bromate formation by reduced graphene oxide supported cerium dioxide during ozonation of bromide-containing water

GO or RGO promotes bromate formation during ozonation of bromide-containing water. CeO₂/RGO significantly inhibits bromate formation compared to RGO during ozonation. CeO₂/RGO shows an enhancement on DEET degradation efficiency during ozonation. Ozone (O₃) is widely used in drinking water disinfection and wastewater treatment. However, when applied to bromide-containing water, ozone induces the formation of bromate, which is carcinogenic. Our previous study found that graphene oxide (GO) can enhance the degradation efficiency of micropollutants during ozonation. However, in this study, GO was found to promote bromate formation during ozonation of bromide-containing waters, with bromate yields from the O₃/GO process more than twice those obtained using ozone alone. The promoted bromate formation was attributed to increased hydroxyl radical production, as confirmed by the significant reduction (almost 75%) in bromate yield after adding t-butanol (TBA). Cerium oxide (less than 5 mg/L) supported on reduced GO (xCeO₂/RGO) significantly inhibited bromate formation during ozonation compared with reduced GO alone, and the optimal Ce atomic percentage (x) was determined to be 0.36%, achieving an inhibition rate of approximately 73%. Fourier transform infrared (FT-IR) spectra indicated the transformation of GO into RGO after hydrothermal treatment, and transmission electron microscope (TEM) results showed that CeO₂ nanoparticles were well dispersed on the RGO surface. The X-ray photoelectron spectroscopy (XPS) spectra results demonstrated that the Ce³⁺/Ce⁴⁺ ratio in xCeO₂/RGO was almost 3‒4 times higher than that in pure CeO₂, which might be attributed to the charge transfer effect from GO to CeO₂. Furthermore, Ce³⁺ on the xCeO₂/RGO surface could quench Br⋅ and BrO⋅ to further inhibit bromate formation. Meanwhile, 0.36CeO₂/RGO could also enhance the degradation efficiency of N,N-diethyl-m-toluamide (DEET) in synthetic and reclaimed water during ozonation.     

负载型TiO2催化臭氧化去除腐殖酸的实验研究

以实验室自制的负载型TiO2为催化剂,研究了其对水中溶解性腐殖酸的催化臭氧化效能。结果表明负载型TiO2对臭氧化去除溶解性腐殖酸有明显的催化作用,反应25min,对腐殖酸的去除率可达到86.8%,较单独臭氧化提高了28.8%;通过Na2CO3对催化反应的影响间接推断TiO2催化臭氧化反应遵循自由基反应的原理;实验最佳条件为:催化剂涂膜层数6层、焙烧温度700℃、溶液pH=10、放电电流0.4A、反应溶液初始浓度10mg/L;催化剂重复使用8次后,其催化活性变化较小,溶液中无钛离子溶出。