UV/H2O2/微曝气联用工艺矿化内分泌干扰物BPA试验研究

采用UV/H2O2,微曝气工艺对水中内分泌干扰物双酚A(BPA)的降解与矿化进行了试验研究.该工艺是在UV/H2O2的基础上发展起来的一种新工艺,微曝气在UV光照射下产生了一定量的O3,提高了·OH的发生率.本试验研究了UV光强、H2O2投加量以及pH值对BPA矿化速率的影响.结果表明,随着UV光强的增大,BPA的矿化速率呈线性增加;当H2O2投加量由5mg/L增大到20 mg/L时,BPA矿化速率常数k由0.003 2上升到0.025 0;当pH为6.68时,在相同条件下BPA的矿化效果最好.在同一工况条件下,UV/H2O2/微曝气工艺降解BPA的速率远远大于其矿化速率,分析得出在开始反应阶段BPA首先被降解为小分子有机物,随着反应的进一步进行小分子有机物逐步被矿化为无机物.     

纳米TiO2光催化氧化酸性嫩黄研究

采用纳米TiO2光催化降解酸性嫩黄.当进水中嫩黄质量浓度为20 mg·L-1时,通过速率常数的比较得出反应的最佳条件为:TiO2的投加质量浓度为600 mg·L-1,pH值为3.56.当向UV/TiO2体系中投加H2O2对,UV/TiO2体系与H2O2具有协同作用.向溶液中充氧也能提高酸性嫩黄的光催化降解速率,但效果不如投加H2O2明显.     

太阳光/硫掺杂Tio2体系对双酚A的氧化性能研究

利用小试试验研究了太阳光和硫(s)掺杂Tio₂体系对水中双酚A(BPA)的降解效能及影响因素.结果表明,太阳光/S掺杂Tio₂体系对纯水中BPA的去除效能较太阳光     

石墨烯掺杂分子筛负载氧化铁芬顿催化降解苯酚影响因素的研究

通过水热晶化法制备了石墨烯掺杂介孔分子筛MCM-41复合载体,利用该载体浸渍负载氧化铁制备了非均相芬顿催化剂gh-MCM-41-Fe.以苯酚为模拟有机废水,考察了催化剂和H2O2投加量、水质因素(苯酚初始浓度、反应温度和水中腐殖酸和草酸)等对gh-MCM-41-Fe芬顿催化降解苯酚效能的影响.结果表明,当苯酚初始浓度为100 mg·L-1,催化剂在60 min催化降解苯酚去除率高达97.6%,COD去除率为65.9%,反应符合准一级反应动力学模型;苯酚降解速率随着催化剂和H2O2投加量的增加而增加,但投加过多会消耗·OH自由基从而不利苯酚降解过程;苯酚初始浓度从10 mg·L-1增至100 mg·L-1,苯酚降解速率相应降低,但体系中H2O2及·OH自由基的有效利用率反而增加;反应温度对于苯酚废水降解率和COD去除率影响不大,反应表观频率因子为105.68 min-1,表观活化能为18.43 k J·mol-1;腐殖酸和草酸对苯酚废水降解和COD去除均有抑制作用.     

纳米TiO2光催化降解海洋石油污染

以紫外灯为光源,考察了自制纳米TiO2在TiO2/H2O2光催化体系中降解海洋石油污染的效率.研究光催化降解催化剂用量、溶液pH值、污染物浓度以及催化时间等因素对光催化降解海洋石油污染的影响。结果表明,纳米TiO2/H2O2光催化体系能有效降解海洋石油污染,且比单独使用纳米TiO2光催化效果好,纳米TiO2光催化/H2O2体系中由于在紫外光的照射下H2O2分解为大量的.OH从而使得降解效率在短时间内大大提高。优化的光催化降解条件为:降解1 L油污染海水的催化剂用量为10 mg、油污染海水的初始浓度为120 mg/L、催化时间为30 min,当pH=6～7时,加入H2O2的体积(质量浓度为60%)为10 mL,油污染海水的降解率可达98.12%。     

TiO2光催化降解水中内分泌干扰物17β-雌二醇

以低压汞灯为光源,采用间歇式光氧化反应器,研究了17β-雌二醇(E2)在纳米TiO2(Degussa P-25)悬浆体系中的光催化降解.考察了溶液pH、E2初始浓度、TiO2光催化剂投加量、UV光强、H2O2、O2对E2光催化降解的影响.结果表明,TiO2光催化工艺可以有效地去除水中的E2,E2的光降解过程符合一级反应动力学模型;TiO2投加量为200 mg/L时,在14 W低压汞灯照射下,初始浓度为400 μg/L的E2在自来水中的光降解一级反应速率常数为0.018 min-1,E2的光催化降解速率常数与其初始浓度、TiO2光催化剂的用量、溶液的pH值、UV光强等因素有关;外加H2O2、O2可以影响催化剂的光降解效率.     

氮掺杂型纳米TiO2在可见光及太阳光下的光催化性能研究

采用钛酸四丁酯为原料,以氨水水解-沉淀法制备出了氮掺杂型纳米TiO2催化剂(N/TiO2),以XRD、XPS、UV-Vis等手段对其进行表征;并通过对偶氮染料橙黄G的降解反应,研究了N/TiO2在可见光及太阳光下的光催化性能,探讨了pH值、外加H2O2氧化剂对光催化降解率的影响,并与P25型纳米TiO2进行了对比.结果表明,在可见光下,N/TiO2对橙黄G具有较高的催化活性,反应150min后降解率可达96.29%,显著高于P25型TiO2(42.55%);在太阳光下,N/TiO2对橙黄G的光催化降解速率较快,反应60min降解率与P25型TiO2基本相同,分别为99.37%、99.94%;较低的pH值环境并适量添加H2O2可显著提高N/TiO2催化效率,在可见光及太阳光下的最佳pH值均为2～3,最佳H2O2加入量分别为0.5mL·L-1、1.5 mL·L-1.     

TiO_2-Cu~(2 )体系降解偏二甲肼的研究

研究了在TiO2 催化氧化降解偏二甲肼的反应体系中添加Cu2 的效果以及Cu2 浓度、添加H2 O2 、反应体系A/V值以及紫外光与太阳光作光源对偏二甲肼降解率的影响 ,结果表明 ,在TiO2 光催化降解偏二甲肼的反应体系中Cu2 的最佳投加量为 4 0mg/L ,添加适量H2 O2 以及在紫外光照射下 ,适当增大反应液的A/V值都会大大提高偏二甲肼的降解率。同时也研究了偏二甲肼降解中间产物随着反应进程的降解规律。     

O3/H2O2降解水中致嗅物质2-MIB的效能与机理

采用O3/H2O2工艺对水中致嗅物质二甲基异莰醇(2-methylisoborneol,2-MIB)的去除效能与机理进行了研究,探讨了H2O2与O2的投加方式、摩尔比以及溶液pH值和水质等因素对2-MIB降解的影响,并通过Gc-MS对2-MIB的氧化降解中间产物进行了分析.实验结果显示,H202能明显促进O3对水中2-MIB的氧化降解.单独臭氧氧化2Omin时2-MIB的降解率为38.7%;在同样体系中加入适量的H202后2.MIB的降解率最大能提高到89.2%,H202与O3最佳投加摩尔比为0.6左右.低浓度(0.5 mg·L-1)腐殖酸对O3/H2O2体系2.MIB的降解速率有比较明显的促进作用,高浓度的腐殖酸则会产生较明显的抑制作用;自由基捕获剂叔丁醇对O3/H2O2体系中2-MIB氧化降解具有明显的抑制作用.鉴定出2-MIB的氧化降解产物有4-羟基-1,7,7-三甲基双环[2,2,1]庚烷-2-酮、1,7,7-三甲基双环[2,2,1]庚烷-2,4-二酮、1,7,7-三甲基双环[2,2,1]庚烷-2-酮等,并对2-MIB氧化机制和降解的可能途径进行了推导.     

UV/H2O2/微曝气联用工艺对BP的去除

采用新型工艺UV/H2O2/微曝气对水中内分泌干扰物(EDCs)4-叔丁基苯酚(BP)的降解进行研究.结果表明,UV/H2O2/微曝气工艺比UV/H2O2工艺可以更为有效地去除水中BP;UV/H2O2/微曝气联用工艺降解BP受BP初始浓度值、UV光强、初始H2O2投加浓度以及溶液初始pH影响较大.随着光强的增大,BP的降解速率呈线性增长;在329～882μg/L浓度范围内,k1随着浓度的增大而逐步降低;随着初始H2O2投加浓度从1mg/L上升到20mg/L,k1几乎呈线性增长;当BP溶液pH值为3.94时,UV/H2O2/微曝气对BP的降解速率最大.     

Charge transfer between biogenic jarosite derived Fe~(3+) and TiO_2 enhances visible light photocatalytic activity of TiO_2

In this work, we have shown that mining waste derived Fe~(3+)can be used to enhance the photocatalytic activity of TiO_2. This will allow us to harness a waste product from the mines, and utilize it to enhance TiO_2 photocatalytic waste water treatment efficiency. An organic linker mediated route was utilized to create a composite of TiO_2 and biogenic jarosite. Evidence of Fe\O\Ti bonding in the TiO_2/jarosite composite was apparent from the FTIR, EFTEM, EELS and ELNEFS analysis. The as prepared material showed enhanced photocatalytic activity compared to pristine TiO_2, biogenic jarosite and mechanically mixed sample of jarosite and TiO_2 under both simulated and natural solar irradiation. The prepared material can reduce the electrical energy consumption by 4 times compared to pristine P25 for degradation of organic pollutant in water. The material also showed good recyclability. Results obtained from sedimentation experiments showed that the larger sized jarosite material provided the surface to TiO_2 nanoparticles, which increases the settling rate of the materials. This allowed simple and efficient recovery of the catalyst from the reaction system after completion of photocatalysis. Enhanced photocatalytic activity of the composite material was due to effective charge transfer between TiO_2 and jarosite derived Fe~(3+)as was shown from the EELS and ELNEFS. Generation of OHU was supported by photoluminesence(PL) experiments.     

β-环糊精强化二氧化钛光催化降解双酚F研究

研究了双酚F在β-环糊精存在的TiO_2光催化体系中的光降解行为,结果表明:双酚F能与β-环糊精形成1:1稳定的包结物,其包结常数为6.33×10~3L/mol,β-环糊精可以使双酚F的光催化降解效率可以提高21%,同时研究了双酚F光降解的动力学规律及pH、β-环糊精浓度、双酚F初始浓度对双酚F的光催化降解的影响。β-环糊精对双酚F光催化降解的强化作用源于β-环糊精促进双酚F在TiO_2表面的吸附。     

VUV/TiO_2/O_3去除水中微量硝基苯的研究

采用负载在钛片上的二氧化钛(TiO2)薄膜光催化剂,以能发射185 nm真空紫外线(VUV)的紫外灯为光源,研究臭氧强化的真空紫外光催化方法(VUV/TiO2/O3)对水中微量硝基苯的去除效果.结果表明,VUV/TiO2/O3是一种有效地去除水中微量硝基苯的方法,VUV/TiO2/O3的表观一级反应速率常数比UV/TiO2/O3和VUV/O3分别高102.8%和30.8%,去离子水中50 μg/L的硝基苯反应60 s后就降低到检测限以下.VUV/TiO2/O3对硝基苯的降解速率随臭氧投加量的增加而显著增大,臭氧投加量1.52 mg/L时的反应速率比不加臭氧时提高了134.4%;虽然表观一级反应速率常数随初始浓度增加而稍有下降,但初始浓度170 μg/L的硝基苯反应2 min后也无法检出.水中常见的重碳酸盐和腐殖酸对硝基苯降解有显著的抑制作用,两者浓度分别为2 mmol/L和3.2 mg/L时,VUV/TiO2/O3对硝基苯的表观反应速率常数分别下降82.9%和71.6%,反应速率常数的倒数与重碳酸氢根浓度线性相关.VUV/TiO2/O3能快速有效地去除地表水(含碳酸盐和天然有机物)中的微量硝基苯,4 min内初始浓度为90 μg/L的硝基苯去除率达到96%,UV254降低了80%.     

Photocatalytic performance and dispersion stability of nanodispersed TiO2 hydrosol in electrolyte solutions with different cations

The existence of electrolytes in aquatic environment on the photocatalytic performance and coagulation of nanodispersed TiO₂ hydrosol and the corresponding photocatalytic alteration were investigated by studying cations (Na⁺, K⁺, Ca ²⁺, Mg²⁺, and Al³⁺). The photocatalysis reactions of nano TiO₂ with different dosages of electrolytes were measured by monitoring the degradation of Rhodamine B (RhB) under ultraviolet A (UV-A) irradiation over time. The results showed that the photocatalytic performance of TiO₂ was improved by the presence of Al³⁺, while the performance was impaired by the other tested cations. The negative influences of divalent ions on the photocatalytic performance of TiO₂ were more significant than monovalent ions. The TiO₂ sol dispersed stable at nano scale at low concentration of electrolyte (< 0.01?mol/L) with slight change of pH, and coagulated into micro sizes at high concentration of electrolytes (> 0.1?mol/L) with larger increase or decrease of pH. The positive effects of Al³⁺ on the photodegradation rate of RhB might relate to the strong hydrolytic action of Al³⁺ in aquatic solutions. The photocatalytic processes of TiO₂ in the presence of all ions followed the Langmuir-Hinshelwood model, and the reaction kinetic constant was increased with the decrease of pH caused by different cations. These work suggested a new perspective about the relationship between coagulation and photocatalytic performance of TiO₂ hydrosols in electrolyte with hydrolysable cations, which demonstrated that TiO₂ hydrosols may be suitable as photocatalysts in aquatic environments.     

An investigation of the fate and behaviour of a mixture of WO_3 and TiO_2 nanoparticles in a wastewater treatment plant

The fate and behaviour of WO_3 and TiO_2 mixture were investigated following the Organisation for Economic Co-operation and Development 303 A guidelines. The nanoparticles were found not to influence the chemical oxygen demand removal efficiency which was maintained 80%hence the activated sludge process was on affected. The nanoparticles were eliminated from the wastewater with a greater percentage of 99.8% for TiO_2 and 95.5% for WO_3 found in the sludge.The activated sludge process also had no effect of the polymorphs of the nanoparticles as X-ray diffraction revealed presence of monoclinic WO_3 and anatase TiO_2 which were spiked into the influent. The nanoparticles were mainly removed by bio-adsorption on the activated sludge surface. The total plate count revealed that the bacterial colonies present in the control and the test units were comparable during the gradual introduction of nanoparticles in the chambers.The biomass was 0.75 MLVSS/MLSS(mixed liquor volatile suspended solids/mixed liquor suspended solids) in both the aeration vessels thus a greater proportion of the sludge were the microorganisms. A greater percentage of the Ti and W found in the effluent was mainly due to the nanoparticles adsorbed on the suspended solids with only 3.6% Ti and 28.6% W due to dissolution of nanoparticles.     

蜂窝陶瓷负载TiO_2光催化降解邻氯苯酚水溶液

采用溶胶 -凝胶技术 (Sol-Gel)制备以蜂窝陶瓷为载体的负载型TiO2 光催化剂。探讨工艺条件对催化降解效果的影响 ;结果表明 ,蜂窝陶瓷表面浸涂 5层TiO2 薄膜 ,经 50 0℃焙烧后 ,具有较高的光催化活性。在紫外光照射下 ,该催化剂降解 1 .0× 1 0 - 3mol/L邻氯苯酚水溶液 2 .5h ,降解率达到 1 0 0 % ;在O3的协同效应下 ,降解率在 1 .5h即可达到 1 0 0 %     

Effect of crystalline structure on terbuthylazine degradation by H2O2-assisted TiO2 photocatalysis under visible irradiation

Various methods for shifting the optical response of TiO₂ into the visible (Vis) range have been reported. Herein, we reported the application of a TiO₂/H₂O₂/Vis process and the effects of TiO2 crystalline structure on the degradation of terbuthylazine. The results indicated that TiO₂ crystalline structure and H₂O₂ addition had significant effects on terbuthylazine degradation: its degradation rate could be increased from 7% to 70% with H₂O₂ addition after 180?min of reaction, the synergistic degradation of terbuthylazine by TiO₂-Fe^{3 +} was substantially accelerated, with the degradation rate reaching up to 100% after 20?min of reaction, and rutile TiO₂ showed better photocatalytic activity and a more obvious synergistic effect than anatase TiO₂. The addition of free-radical scavengers (tert-butyl alcohol or methanol) inhibited the degradation efficiency of rutile TiO₂, but had a relatively minor effect on anatase TiO₂. Fluorescence spectrophotometry analysis indicated that hydroxyl free radicals could be continuously produced when using rutile TiO₂ as the photocatalyst. Degradation of terbuthylazine catalyzed by rutile TiO₂ occurred mainly in solution, but occurred on the particle surface of the photocatalyst when catalyzed by anatase TiO₂. This study provides new insight into the role of TiO₂ crystalline structure on the degradation of terbuthylazine and its photocatalytic degradation mechanism.     

UV/TiO_2/H_2O_2法对高浓度有机废水降解的应用研究

用UV TiO2 H2 O2 法对高浓度有机废水降解的实验表明 ,当TiO2 、H2 O2 的投加量分别为 2 0g与 1% ,反应时间为3h时 ,CODCr、Oil、Ar OH、NH3 N、S2 - 的平均去除率分别达到 73 %、83 %、86%、5 0 %、10 0 %。此处理工艺具有除臭、除色、快速高效、不产生污泥等优势。实验过程探索了TiO2 、H2 O2 的用量对各污染物降解率的影响 ,并设计了有实用意义的反应器     

二氧化钛悬浆体系太阳光催化降解甲基橙研究

利用太阳光作为光源，采用二氧化钛悬浆体系，考察了甲基橙溶液光催化降解反应中影响反应速度的相关因素．实验结果表明，太阳光强度、二氧化钛的投加量、反应器的Ａ／Ｖ值、溶液的初始浓度是影响反应速率的重要因素．在平均照度为９２６００ｌｘ的晴天，初始浓度为２０ｍｇ／Ｌ的甲基橙溶液，初始ｐＨ为３８８，反应器Ａ／Ｖ值为３６ｍ－１时，光照２ｈ后色度去除率达９０％以上，４ｈ后ＴＯＣ去除率接近７０％．实验结果证明了非聚焦开放式反应器构型和二氧化钛悬浆体系能很好地利用太阳能、有效地完成对甲基橙的脱色和有机碳的去除．各因素与甲基橙脱色速率的关系将作为进一步设计反应器的重要参数．     

ZnFe_2O_4/TiO_2光催化剂制备及乙酰甲胺磷降解性能研究

分别采用共沉淀法和溶胶-凝胶法制备了ZnFe2O4和掺杂ZnFe2O4的纳米级TiO2光催化剂,进行了XRD、TEM和UV visDRS表征,以卤素灯为光源对纳米TiO2降解水溶液中乙酰甲胺磷农药进行了研究。考察了反应液初始pH值、催化剂用量、H2O2用量对降解率的影响。实验结果表明,焙烧温度为400℃、掺杂量为0.5%的ZnFe2O4/TiO2纳米粉体降解效果最佳,在相同条件下,反应2h后农药降解率可比纯TiO2提高20%左右。正交实验优化了降解反应条件,在常温常压下,起始pH值为12、H2O2浓度为12mmol/L、催化剂浓度为0.5g/L、反应3h后,初始浓度为1.0×10-4mol/L的乙酰甲胺磷农药降解率可达61.2%。