三维电场协同TiO2光催化降解水中双酚A的研究

采用溶胶-凝胶法制备TiO2/Ti膜电极,设计了三维电极电助光催化降解反应装置,并将其用于降解水中的双酚A.结果表明,三维电场协同TiO2光催化氧化技术对双酚A的降解效果较好,反应120 min后降解率可达100%;在本试验条件下,最佳阳极偏电压为8 V;当溶液的电导率较小时,增大电导率有利于对双酚A的降解,但当电导率较大时,对双酚A的降解率反而随电导率的增大而逐渐减小;电助光催化降解双酚A的反应符合表观一级动力学方程.     

固定床电-多相催化反应器处理硝基苯废水

研究了固定床电-多相催化反应器氧化处理硝基苯废水的性能，分别考察了电解电压、Na2SO4浓度、pH值对硝基苯去除率的影响；通过正交试验确定了各因素对硝基苯去除率的影响大小，并得出了去除硝基苯的最佳条件：进水初始pH值为10、电解电压为40V、Na2SO4浓度为1000mg／L。在正交试验的基础上，考察了各因素对硝基苯去除率的影响规律，并通过长期运行试验考察了反应器的稳定性，反应器在连续重复运行40次内稳定性较佳。通过对中间产物的GCMS分析，探讨了反应器降解硝基苯的机理。     

实用型光催化氧化水处理器深度处理焦化废水

解决光催化剂与废水的即时分离问题是光催化氧化技术走向实际的关键之一。采用新型的实用型光催化水处理器——连续流即时分离型光催化反应器深度处理焦化废水,发现在适宜的反应时间、TiO2投加量、光辐照强度和初始pH值下是完全可行的。然后在此基础上选用H2O2和Fenton试剂为外加氧化剂,研究了氧化剂强化光催化深度处理焦化废水的效果。结果表明,在UV/TiO2氧化体系中投加H2O2或Fenton氧化剂,可显著提高光催化氧化对COD和色度的去除率;在最佳反应条件下,不同氧化体系对焦化废水的深度处理效果排序为:UV/TiO2/Fenton>UV/TiO2/H2O2>UV/TiO2。     

一种新型电助光催化氧化反应器

设计了一种新型电助光催化氧化反应器--内外同心圆柱形反应器.考察了直流电压、电极布置方式、水力停留时间、反应器高度和半径等因素对反应器的影响,并分析了影响反应器设计的结构因子.研究表明,该反应器可有效降解苯甲酰胺.在本研究中,当反应器半径为3.5 cm,停留时间为120 min,直流电压为1.016 V时,苯甲酰胺的稳定去除率可达95%.     

可见光下Fe、N/TiO_2-GF法降解硝基苯废水的试验研究

以氙灯散发的可见光为光源进行光催化氧化试验,分析在氙灯下Fe、N/TiO_2-GF改性负载光催化剂对硝基苯废水的处理效果。试验所用的硝基苯废水是自行配制的,以硝基苯的去除率为指标,采用溶胶-凝胶/浸渍-提拉制备掺杂改性负载型TiO_2光催化剂,考察共掺杂负载型光催化剂的催化性能及废水初始pH、初始浓度对降解效果的影响。氙灯照射下,Fe、N/TiO_2-GF共掺杂改性负载光催化剂对硝基苯废水的处理效果较好。对于浓度为40mg/L,pH为3.28的硝基苯废水,氙灯光照射2.5h,Fe、N/TiO_2-GF光催化对硝基苯去除率可达92.6%。     

TiO_2光催化降解亮蓝的研究

研究了TiO_2降解亮蓝的光催化反应.首先考察了亮蓝初始浓度、TiO_2的用量、pH值、光生空穴捕获剂O_2与电子捕获剂甲醇等反应条件对TiO_2降解亮蓝光催化效率的影响;然后研究了TiO_2降解亮蓝的光催化反应动力学.研究结果表明:当亮蓝初始浓度为2mg/L、溶液pH值为5时,在紫外灯照射60min下,亮蓝的降解可达96%.O_2对TiO_2降解亮蓝的光催化反应具有促进作用;甲醇对TiO_2降解亮蓝的光催化反应具有抑制作用.当亮蓝的初始浓度为8mg/L时,TiO_2降解亮蓝的光催化反应动力学遵循假一级反应动力学,反应速率常数为0.0345min-1,半衰期为20.09min.     

可降解硝态氮的歧化厌氧氨氧化颗粒污泥的驯化

向SBR反应器中接种成熟的厌氧氨氧化颗粒污泥,在氨氮、亚硝态氮浓度均为100mg/L的条件下,按C/N值=0.1添加乙酸钠,研究乙酸钠对厌氧氨氧化菌去除氮素的影响。结果表明,在存在乙酸钠的条件下,出水硝态氮生成量为没有乙酸钠情况下的45%,对总氮的去除率提高到90%以上,有利于出水总氮浓度达到一级A标准。验证了在C/N值=0.1条件下,厌氧氨氧化反应是反应器中的主体反应,没有被反硝化反应取代。厌氧氨氧化菌可利用乙酸钠和硝态氮的代谢机制也为降低短程硝化控制难度提供了一种思路。     

废水中硝基苯的光催化降解实验研究

采用锐钛型TiO2光催化剂,对废水中的硝基苯进行光催化降解,探究了催化剂投放量、硝基苯浓度、溶液的pH值及反应时间等因素对降解效率的影响,实验结果表明,以锐钛型Tiol为催化剂的光催化技术对硝基苯有理想的处理效果;催化剂投放量控制在3g／L;废水的初始pH对硝基苯的处理效果影响不大;紫外光照射6．5h,降解效率基本稳定在78％。     

蒽醌粒子复三维电极生物膜反应器反硝化特性

制备了蒽醌粒子电极,并采用复三维电极生物膜反应器进行生物反硝化反应。通过扫描电镜和红外光谱对粒子电极进行了表征。结果表明,蒽醌活性炭粒子电极结构紧密,内部具有微孔结构,有利于微生物生长;电极表面富含醌基官能团,可有效提高反硝化速率;复三维电极生物膜反应器具有良好的p H值缓冲能力,当p H值为8、进水流量为110 m L/h、外加电流为15 m A时,填充蒽醌粒子电极的反应器平均电流效率可达到128%,能效较高,且反硝化效果好,硝酸盐氮的去除率为61%,分别是商品活性炭电极反应器和空白粒子电极反应器的2.77和1.22倍。     

超高温两相厌氧反应器处理黄浆废水

采用超高温(70℃)两相厌氧反应器处理玉米加工过程中产生的黄浆废水,考察了进水COD浓度和负荷、C/N值等对系统除污效能的影响。结果表明:工艺运行稳定,在低C/N值和低负荷条件下,产酸反应器对COD的去除率为 47. 5%,酸化率(VFA/COD)为 52. 7%,蛋白质水解率为 95%,产甲烷反应器对COD的去除率为 91. 8%,两相总去除率为 97. 0%;在中高进水COD浓度和低C/N值条件下,产酸反应器对COD的去除率为 57. 6%,产甲烷反应器的为 88. 1%,两相总去除率为 93. 8%。当C/N值大幅度增加时产酸反应器对COD的去除率明显降低,而产甲烷反应器则有所增加,使总去除率仍可达 90%以上。     

Hybrid reactor for priority pollutant nitrobenzene removal

The performance of a hybrid reactor, comprising of trickling filter and activated sludge process, in treating nitrobenzene wastewater was investigated. Acetate induced cells of mixed consortia was acclimatized with gradual increase of nitrobenzene concentration up to 90 mg/l in 100 days using sodium acetate as co-substrate and considering COD and nitrobenzene concentration as paramount parameters for assessing the growth of biofilm and acclimation. A removal of 60-95.80% COD and 80-90.23% nitrobenzene was observed during acclimation. During hydraulic retention time (HRT) studies, the optimum HRT was found to be 29.55 h at which a maximum of 95.83% COD and 97.93% nitrobenzene removal was observed. Other studies included optimization of C:N ratio, substrate:co-substrate ratio, effect of shock loading and estimation of volatilization losses. The optimum C:N ratio was found to be 100:20 at which maximum 97.93% removal of nitrobenzene was observed. At optimum HRT (29.55 h) and optimum C:N ratio (100:20) optimum substrate:co-substrate ratio was found to be 1:33. From the shock load studies it can be concluded that the system can withstand shock load up to two times of usual nitrobenzene concentration. A loss of 9.44% nitrobenzene was observed due to volatilization and mass balance gave an efficiency of 87.49% biological removal of nitrobenzene.     

Application of nano TiO(2) towards polluted water treatment combined with electro-photochemical method

A novel composite reactor was prepared and studied towards the degradation of organic pollutants in this work. In the reactor, a UV lamp was installed to provide energy to excite nano TiO(2), which served as photocatalyst, leading to the production of hole-electron pairs, and a three-electrode electrolysis system was used to accumulate H(2)O(2) which played an important role in the degradation process. The reactor was evaluated by the degradation process of rhodamine 6G (R-6G), and the data obtained in the experiments showed that the combination of the photochemical and electrochemical system raised the degradation rate of R-6G greatly; the working mechanism of the reactor was also discussed in the article. The prepared reactor was also utilized to treat polluted water from dyeing and printing process. After continuous treatment for 0.5h, chemical oxygen demand biochemical oxygen demand, quantity of bacteria and ammonia nitrogen of the polluted water were reduced by 93.9%, 87.6%, 99.9% and 67.5%, respectively, which indicated that the method used here could be used for effective organic dyes degradation.     

铁炭Fenton/SBR法处理硝基苯制药废水

为探寻硝基苯废水的适宜处理工艺，开展了铁炭Fentort／SBR工艺处理硝基苯制药废水的试验研究。结果表明，铁炭内电解结合Fenton氧化的预处理工艺可有效去除废水中的硝基苯类物质，并提高了废水的可生化性。当原水的pH值为2～3、H2O2投加量为500～600mg／L时，调节预处理出水pH值至7～8并经沉淀处理后，对COD和硝基苯类物质的总去除率分别可达47％和92％。后续混合废水经SBR工艺处理后出水水质能满足国家污水排放标准。     

微好氧与厌氧水解酸化对明胶废水的预处理效果

以明胶废水为研究对象,采用微好氧与厌氧水解酸化工艺进行对比处理实验,探讨了不同水力停留时间下微好氧与厌氧水解酸化对明胶废水水质改善的效果。实验结果表明,在水力停留时间达到72h的时候,溶解氧为1.3~1.6mg/L的微好氧反应器的COD去除率最大可达25%,溶解氧为0.3~0.5mg/L的厌氧反应器的COD去除率最大可达22%;微好氧反应器的VFA的含量达到12mg/L左右,厌氧反应器只有8mg/L左右;微好氧反应器的pH值可由最初的12.5降至7.5左右,而厌氧反应器只能降至8.0左右;两个反应器对蛋白质去除效果的差别并不明显,都可以达到90%以上,但是微好氧反应器的氨氮浓度只有22mg/L,小于厌氧反应器中的氨氮浓度,说明微氧条件有利于氨氮的扩散挥发,低浓度的氨氮对微生物的危害较小。对比得出微好氧反应器的出水水质较好,更适合明胶废水水解酸化的预处理。     

生物滤池/生态砾石床处理含氮微污染地表水

采用生物滤池/生态砾石床组合工艺进行了微污染地表水(含低碳、高NO3--N浓度)的脱氮研究,通过投加乙酸钠为碳源考察了C/N值、温度、水力负荷对反应器脱氮效能的影响。结果表明,C/N值对反应器的脱氮效能影响较大,在C/N值为10时可以取得较高的反硝化效率(>90%)。在低温下(2～10℃)反应器的反硝化效能受到严重抑制;在13～17℃条件下,反硝化效率恢复到60%左右;当水温>20℃时,在水力负荷为8 m3/(m2.h)的条件下(此时生物滤池和生态砾石床的水力停留时间分别为15、30 min),对NO3--N的去除率能够达到90%以上。生态砾石床能够将生物滤池出水中残余的碳源去除,保证了出水的水质安全。     

低溶解氧下微膨胀污泥对污染物的去除性能

维持SBR反应器好氧段的平均DO为0.30 mg/L,采用好氧/缺氧的运行方式研究了微膨胀污泥在低溶解氧状态下去除污染物的效果.结果表明:在丝状菌污泥微膨胀状态下反应器的除污效果仍较好,出水SS含量很低,对COD、氨氮的去除率分别可达80%、90%以上,同时可以节省曝气量约25%.可见,在低溶解氧状态下采用微膨胀活性污泥处理生活污水是可行的.     

Biological hydrogen production by Clostridium acetobutylicum in an unsaturated flow reactor

A mesophilic unsaturated flow (trickle bed) reactor was designed and tested for H2 production via fermentation of glucose. The reactor consisted of a column packed with glass beads and inoculated with a pure culture (Clostridium acetobutylicum ATCC 824). A defined medium containing glucose was fed at a flow rate of 1.6 mL/min (0.096 L/h) into the capped reactor, producing a hydraulic retention time of 2.1 min. Gas-phase H2 concentrations were constant, averaging 74 +/- 3% for all conditions tested. H2 production rates increased from 89 to 220 mL/hL of reactor when influent glucose concentrations were varied from 1.0 to 10.5 g/L. Specific H2 production rate ranged from 680 to 1270 mL/g glucose per liter of reactor (total volume). The H2 yield was 15-27%, based on a theoretical limit by fermentation of 4 moles of H2 from 1 mole of glucose. The major fermentation by-products in the liquid effluent were acetate and butyrate. The reactor rapidly (within 60-72 h) became clogged with biomass, requiring manual cleaning of the system. In order to make long-term operation of the reactor feasible, biofilm accumulation in the reactor will need to be controlled through some process such as backwashing. These tests using an unsaturated flow reactor demonstrate the feasibility of the process to produce high H2 gas concentrations in a trickle-bed type of reactor. A likely application of this reactor technology could be H2 gas recovery from pre-treatment of high carbohydrate-containing wastewaters.     

Effects of nitrobenzene and zinc on acetate utilizing methanogens

Determination of anaerobic degradation rates and toxic effects of nitrobenzene (NB) on acetate utilizing methanogens was the first objective of this research. Serum bottles were used for anaerobic toxicity assays with an acetate enrichment culture of methanogens. Ten mg/l of nitrobenzene did not inhibit total gas production in the acetate enrichment methanogenic culture. Twenty and thirty mg/l of nitrobenzene caused reversible inhibition of methanogenesis. Batch kinetic experiments showed that 20 mg/l of nitrobenzene was degraded with a first-order rate constant, k, of 0.37 d⁻¹. Acetate was not degraded during the first 7 days when the measured nitrobenzene concentration was higher than about 1 mg/l. The second objective was to determine the effect of zinc on nitrobenzene degradation in methanogenic systems. Ten mg/l of spiked zinc caused a reduction of gas production in the systems with 10 mg/l of nitrobenzene; 20 mg/l of zinc led to failures of systems with 10 and 20 mg/l of nitrobenzene. With 10 and 20 mg/l of added zinc, the k value for nitrobenzene degradation decreased to 0.18 d⁻¹ and 0.14 d⁻¹, respectively. With 20 mg/l of Zn, acetate was not degraded at all even after nitrobenzene concentration reached 0.1 mg/l, indicating toxicity of Zn to methanogenesis. Abiotic control tests with autoclaved culture showed that adsorption alone could remove 60–70% of spiked nitrobenzene in 36 days. However, the samples extracted from solids in the methanogenic test systems showed that nitrobenzene was below the detection limit of 0.1 mg/l, indicating biodegradation of nitrobenzene in these systems. Traces of benzene were seen as an intermediate in the liquid samples. Headspace analysis showed that nitrobenzene and benzene were below detection limits.     

Preliminary trial on degradation of waste activated sludge and simultaneous hydrogen production in a newly-developed solar photocatalytic reactor with AgX/TiO2-coated glass tubes

A solar fluidized tubular photocatalytic reactor (SFTPR) with simple and efficient light collector was developed to degrade waste activated sludge (WAS) and simultaneously produce hydrogen. The photocatalyst was a TiO₂ film doped by silver and silver compounds (AgX). The synthesized photocatalyst, AgX/TiO₂, exhibited higher photocatalytic activity than TiO₂ (99.5% and 30.6% of methyl orange removal, respectively). The installation of light collector could increase light intensity by 26%. For WAS treatment using the SFTPR, 69.1% of chemical oxygen demand (COD) removal and 7866.7 μmol H₂/l-sludge of hydrogen production were achieved after solar photocatalysis for 72 h. The SFTPR could be a promising photocatalysis reactor to effectively degrade WAS with simultaneous hydrogen production. The results can also provide a useful base and reference for the application of photocatalysis on WAS degradation in practice.