纳米TiO2光催化技术在工业废水处理中的应用

介绍纳米TiO2的光催化特性,概述纳米TiO2光催化技术在降解印染废水、农药废水、造纸废水、表面活性剂废水以及含苯酚类、石油类和重金属污染物废水处理中的应用研究进展,总结了纳米TiO2应用于废水工业化处理所存在的问题,认为该技术研究领域近期内的主要发展方向为:大力开展纳米TiO2的改性技术、固定化技术和纳米TiO2光催化降解实际工业有机废水的试验研究及其高效、多功能、集成式光催化反应器的研制。     

纳米TiO2/海泡石复合光催化材料性能研究

纳米TiO2因其具有安全无毒、稳定性好、光活性强等特性,在水污染治理领域被广泛用作光催化剂。然而纳米TiO2在水介质中存在难以回收、容易流失、不易分散等问题,限制了其实际应用,将其进行固定化负载是有效的解决手段。以矿物海泡石为负载载体,采用一种简单易行的粉末烧结法制备出纳米TiO2/海泡石复合光催化材料,并通过透射电镜、扫描电镜、X射线衍射、紫外－可见分光光度计等手段对材料进行微结构表征,利用化学荧光技术测试了复合材料光催化活性。研究表明,海泡石的加入能够显著抑制复合光催化剂中纳米TiO2的团聚,增强其在紫外至可见光波长范围内的光吸收强度,从而增强复合体的光催化活性。对比研究不同负载配比对材料光催化活性的影响,发现90%TiO2/海泡石光催化活性最佳。     

丝光沸石负载二氧化钛膜光催化降解邻氯苯酚

利用溶胶法将TiO2负载在天然丝光沸石上制成TiO2薄膜,在125 W高压汞灯照射下,对邻氯苯酚溶液进行光催化氧化反应,研究负载后的催化剂活性。通过实验得出,沸石作为一种多孔性的催化剂载体,在反应中通过吸附作用增加催化剂表面的邻氯苯酚浓度,可显著提高光催化剂活性。     

Fenton试剂与TiO_2光催化氧化农药废水研究

以合肥市循环经济园区某农药厂的生产废水为研究对象,分别将Fenton高级氧化法和TiO2光催化氧化法应用于农药废水的预处理,研究了反应时间、pH值、H2O2投加量、TiO2投加量等对CODCr去除率的影响。结果表明:Fenton高级氧化法和TiO2光催化氧化法在处理农药废水方面都具有一定的效果;H2O2投加量是影响Fenton试剂氧化农药废水的主要因素,当初始pH值为4、反应时间为90 min、Fe2+的投加量为0.04 mol/L、H2O2投加量为0.4 mol/L时,Fenton高级氧化法的处理效果最好;在光催化氧化试验中,当初始pH值为9、反应时间为120 min、TiO2投加量为2.64 g/L时,TiO2光催化氧化效果最佳。     

P25对TiO_2镀膜光催化活性的影响

通过向钛酸四正丁酯溶胶中添加纳米级TiO2粉末（P25）,来提高煅烧TiO2镀层的光催化活性。用不锈钢丝网作为煅烧TiO2镀层载体,以甲基橙降解效果来衡量TiO2镀层的光催化活性。实验结果表明,当溶胶中P25添加量为1g／L、镀膜次数为4次时,镀层光催化活性达到最大,150min内甲基橙降解率达到69．8％。     

光催化氧化技术在水处理中的研究进展

介绍了二氧化钛(TiO2)光催化氧化的机理,阐述了TiO2光催化氧化技术在降解水中有机污染物、无机污染物及饮用水净化和垃圾渗滤液处理中的研究进展,并对TiO2光催化氧化技术的研究前景进行了展望.二氧化钛(Ti02)化学性质稳定、难溶、无毒、成本低、催化效率高,因此光催化氧化技术在难降解有机物、微污染水等处理中相对于其他传统水处理工艺具有一定的优势,是一种很有发展前途的水处理技术,对太阳能的利用和环境保护有重要的意义,可以预见光催化氧化将成为新型有效的水处理手段.     

光催化技术降解城市排水泵站恶臭气体的研究

光催化技术作为一种新兴的环境净化技术,其研究和开发已受到广泛的重视。本研究以泵站恶臭气体中常见的氨和硫化氢为处理对象,在城市排水泵站现已使用的高端紫外光除臭设备中使用负载型二氧化钛（TiO2）光催化剂,通过泵站的应用来研究光催化技术对恶臭气体的降解效果。     

纳米TiO2光催化在废水治理中的研究与应用

介绍了纳米TiO2的光催化机理,讨论了其在废水处理中的不足之处以及近年来的改进手段。概述了光催化技术在处理含油废水、含药废水、印染废水、造纸废水、表面活性剂废水、重金属污染物废水等方面的最新应用研究进展,指出了其在废水处理中还存在阳光效率低、回收再利用困难、降解效率有限等问题及今后的研究趋势。     

纳米TiO2光催化剂可见光响应的改性研究

综述纳米TiO2光催化剂对可见光响应的改性研究,介绍复合半导体、染料光敏化及非金属掺杂改性的方法,可以将只能由UV光激发的TiO2光催化反应红移到可见光区域进行。文中最后提出了金属与非金属复合掺杂改性TiO2是今后的一个重要研究方向,并存在巨大的研究空间。     

负载型纳米TiO2光催化降解罗丹明B动力学与机理研究

采用负载型纳米TiO2/AC在流化床反应器中降解罗丹明B染料废水。研究了罗丹明B的光催化降解反应动力学与降解机理。结果表明,负载型纳米TiO2光催化降解罗丹明B过程符合一级动力学方程,降解机理首先是罗丹明B分子发色基团苯氨基、羰基键被破坏,然后是无色中间产物的逐渐降解。     

Application of immobilized cells to the treatment of cyanide wastewater.

Cyanide is highly toxic to living organisms, particularly in inactivating the respiration system by tightly binding to terminal oxidase. To protect the environment and water bodies, wastewater containing cyanide must be treated before discharging into the environment. Biological treatment is a cost-effective and environmentally acceptable method for cyanide removal compared with the other techniques currently in use. Klebsiella oxytoca (K. oxytoca), isolated from cyanide-containing industrial wastewater, has been shown to be able to biodegrade cyanide to non-toxic end products. The technology of immobilized cells can be applied in biological treatment to enhance the efficiency and effectiveness of biodegradation. In this study, potassium cyanide (KCN) was used as the target compound and both alginate (AL) and cellulose triacetate (CTA) techniques were applied for the preparation of immobilized cells. Results from this study show that KCN can be utilized as the sole nitrogen source by K. oxytoca. The free suspension systems reveal that the cell viability was highly affected by initial KCN concentration, pH, and temperature. Results show that immobilized cell systems could tolerate a higher level of KCN concentration and wider ranges of pH and temperature, especially in the system with CTA gel beads. Results show that a longer incubation period was required for KCN degradation using immobilized cells compared to the free suspended systems. This might be due to internal mass transfer limitations. Results also indicate that immobilized systems can support a higher biomass concentration. Complete KCN degradation was observed after the operation of four consecutive degradation experiments with the same batch of immobilized cells. This suggests that the activity of the immobilized cells can be maintained and KCN can be used as the nitrogen source throughout KCN degradation experiments. Results reveal that the application of immobilized cells of K. oxytoca is advantageous to the maintenance of KCN degradation efficiency. Thus, it is conceivable that the immobilized cells of K. oxytoca would be applicable to the treatment of cyanide-containing wastewaters.     

水环境中PPCPs的臭氧氧化和高级氧化技术

药物和个人护理用品(PPCPs)是最近十年引起关注的一类新型有机微量污染物,其对人类健康和生态环境安全的影响受到了越来越多的关注.传统的给水处理和污水处理工艺都不能有效去除水中的PPCPs,因此有必要采用臭氧氧化、高级氧化等工艺进行深度处理.臭氧是选择性氧化剂,其与PPCPs的反应受PPCPs的基团电子特性和溶液pH的影响;高级氧化技术产生的羟基自由基·OH氧化能力强,与PPCPs的反应没有选择性,主要包括O_3/H_2O_2、UV/H_2O_2、UV/TiO_2、芬顿和光芬顿氧化等.这些深度处理工艺的采用受一些因素的限制,同种工艺或不同工艺的组合能达到更高的去除效率.     

废水处理光催化反应器研究进展

综述近年来在废水处理过程中光催化反应器的研究现状。根据光催化反应器中的光催化剂存在形式及应用情况,将反应器分成悬浮式、负载式和耦合式三类,并系统地介绍了这三类反应器的结构、性能及其在应用中的优缺点,提出了废水处理中光催化反应器研究与设计所面临的问题及发展方向。     

An antimicrobial polycationic sand filter for water disinfection

A new sand filtration water disinfection technology is developed which relies on the antimicrobial properties of hydrophobic polycations (N-hexylated polyethylenimine) covalently attached to the sand's surface. The efficacy of the filter disinfection process was evaluated both with water spiked with E. coli and with real aqueous effluent from a wastewater treatment plant. For the former, over 7-log reduction in bacterial count was achieved. With real environmental wastewater secondary effluent samples, the E. coli concentration reduction declined to under 2 logs. This reduced inactivation efficiency compared to the model aqueous sample is likely due to the particulate or colloidal matter present that diminishes the contact between the immobilized polycation and the suspended bacteria. Preliminary sand washing methods were tested to assess potential 'regeneration' approaches. Potential advantages of the proposed approach over conventional disinfection in terms of eliminating harmful by-products and reducing energy consumption are discussed.     

臭氧技术在污水处理中的应用

臭氧作为一种强氧化剂,主要用于污水的深度处理。本文介绍了臭氧氧化的机理,探讨了臭氧及臭氧高级氧化在污水深度处理以及降解痕量有机物方面的应用,并在此基础上对今后的研究方向进行了展望,提出如何避免副产物的产生将是今后的研究重点。     

Simultaneous photocatalytic oxidation of pharmaceuticals and inactivation of Escherichia coli in wastewater treatment plant effluents with suspended and immobilised TiO(2)

Simultaneous Escherichia coli inactivation and oxidation of pharmaceuticals in simulated wastewater treatment plant effluents has been investigated using a photocatalytic treatment with TiO(2) in suspension and immobilised onto a fixed-bed reactor. Non-photocatalytic reference experiments of dark adsorption and photolysis showed a higher sensitivity of E. coli towards the chemical composition of water in comparison with the concentration of pharmaceuticals that remains unaffected. Moreover, it must be underlined that the presence of pharmaceuticals (including antibiotics) did not seem to affect the bacterial viability at such low concentrations. Concerning photocatalytic experiments, both suspended and immobilised TiO(2) were able to simultaneously inactivate and oxidise both kinds of pollutants (bacteria and pharmaceuticals). The fixed-bed reactor showed similar activity to that of the slurry without deactivation after several cycles of reuse. That makes TiO(2) photocatalysis a quite interesting technology for the treatment of drinking water supplies or wastewater plant effluents, allowing the removal of emerging contaminants such as pharmaceuticals during the disinfection treatment.     

Submerged membrane bioreactor using fly ash filters: trials with distillery wastewater

This work presents preliminary results for distillery wastewater treatment in a MBR equipped with filters prepared from waste fly ash. The system was fabricated locally and employed submerged membranes in the 2-8 microm pore-size range. Distillery wastewater, after anaerobic digestion, was used as the feed and the bioreactor was inoculated with sludge obtained from a local distillery unit. The MBR was operated for around 250 days. The wastewater quality was monitored in terms of COD (chemical oxygen demand), colour, phenol, and MLSS (mixed liquor suspended solids) concentration. An average COD and phenol removal of 36% and 60% respectively was obtained. The maximum suspended solids retention by the ash filter was as high as 98%. The results were encouraging and further trials are currently underway to improve the performance.     

固定化细胞去除废水中硝态氮的试验研究

通过对常用的聚乙烯醇-硼酸固定化方法优化改进,有效解决了固定化细胞技术在废水处理领域推广应用中所面临的机械强度小、易破碎、发胀粘连和带气上浮等问题。对包埋固定化反硝化菌与未包埋反硝化菌处理含硝态氮的废水进行比较,结果表明:固定化反硝化菌在不适宜的pH值、温度和有氧条件下均比未包埋菌具有明显的耐受性,表现出良好的反硝化特性,并且能和硝化细菌在同一反应器中进行单级生物脱氮,总氮去除率达到52%,因而在处理含氮废水中具有一定的实际应用价值。     

接触氧化工艺中生物填料的发展及应用

选择合适的生物填料可以有效地提高接触氧化工艺的处理效果。对接触氧化工艺中采用较多的硬性、软性、半软性、组合型、悬浮型及固定化微生物型填料进行了分类介绍,分析了各自的构造、挂膜性能、有机物去除效率等。认为悬浮型、生物密集型、固定化微生物型填料将会成为今后生物填料的发展方向。