SiO_2/TiO_2复合膜光催化降解胶片废水的研究

以煤矸石烧结滤料为载体,以SiO2/TiO2复合膜为催化剂,在自制的紫外光光催化反应器中,以去除胶片废水的色度为研究目标,考察了废水色度、pH、曝气/光照对SiO2/TiO2复合膜光催化活性的影响.结果表明,当废水的初始吸光度为0.554、光催化降解的时间为2 h时.SiO2/TiO2复合膜光催化降解胶片废水的脱色率可达到99.4%;脱色率与光照时间呈线性相关(R2=0.994 2),且可用Langmuir-Hinshelwood一级动力学模型进行拟合,表观速率常数为0.027 5min-1;SiO2/TiO2复合膜光催化降解胶片废水的处理费用约为1.2元/m3,较接触氧化工艺的处理成本低,有一定的工程应用价值.     

负载型纳米TiO_2光催化降解酸性红B的研究

为解决传统纳米TiO2光催化氧化工艺催化剂不易分离和载体的比表面积较小、悬浮性差的问题,将纳米TiO2负载在聚丙烯多面球上制备了负载型TiO2光催化剂.利用XRD和氮气吸附法表征了该催化剂的结构特性,并采用其降解酸性红B,考察了初始浓度、曝气量、pH值、H2O2投加量、自由基清除剂及多面球的比表面积等对降解效果的影响.结果表明,偶联剂法制备的TiO2薄膜晶相单一(锐钛矿型),晶体粒度较小,比表面积较大;脱色率会随着酸性红B溶液初始浓度的升高和自由基清除剂(乙醇)的加入而下降,提高溶解氧浓度、增加聚丙烯多面球的比表面积以及酸性条件(pH=3.26时效果最佳)都有利于提高脱色率;投加H2O2也能提高脱色率,但当投加量增至0.5 mg/L后效果不再明显;酸性红B的光催化降解遵循一级反应动力学方程.     

TiO_2光催化降解TCAA及其动力学研究

三氯乙酸(TCAA)是饮用水中普遍存在,且难以去除的高致癌风险物.考察了通气种类、TiO2用量、溶液初始pH及共存的Fe2+浓度等因素对TiO2光催化降解TCAA效率的影响,分析了pH对TiO2光催化降解TCAA效率的影响机理,探讨了TiO2光催化降解TCAA反应动力学及Fe2+促进TiO2光催化降解TCAA反应的机理.结果表明,当通入气体为O2、TCAA初始浓度为2.0mg/L、TiO2用量为1.0g/L、溶液初始pH为5.80,共存Fe2+浓度为0.10mmol/L时,反应120min,TiO2光催化降解TCAA效率为96.18%;用Langmuir-Hinshelwood模型模拟TiO2光催化降解TCAA反应动力学,UV/TiO2、Fe2+/UV/TiO2反应体系对TCAA的降解速率常数分别为0.0131、0.0237min-1,半衰期分别为52.92和29.25min.     

TiO_2固定膜光催化降解甲胺磷农药废水

采用自制的TiO2 固定膜浅池反应器对经生化处理后的甲胺磷农药废水进行了降解试验。经处理后废水中的COD降为 5 9.3mg/L、有机磷被全部降解为无机磷 ,达到《污水综合排放标准》(GB 8978- 1996 )中的一级排放标准。     

TiO2-活性炭组合光催化降解苯酚废水

论证了TiO2－活性炭组合光催化降解苯酚废水的可行性。试验结果表明，同单纯TiO2悬浮体系相比，组合体系对苯酚的去除率显著提高，降解时间亦随之减少。活性炭的加入显著增强了TiO2光降解苯酚的能力。     

纳米TiO_2对水中对羟基苯甲酸吸附及光催化降解

以BDH粉末TiO2为光催化剂,研究了水体中对羟基苯甲酸在纳米Ti02颗粒上的吸附行为,并研究了时羟基苯甲酸的二氧化钛光催化降解效果.结果表明:TiO2对羟基苯甲酸的吸附作用明显依赖于水溶液的pH,对羟基苯甲酸的光催化降解效果与其在催化剂表面的吸附行为密切相关,提高吸附速率,对羟基苯甲酸的去除率也随之提高.     

纳米二氧化钛光催化氧化降解苯酚废水实验

开展实验室模拟苯酚废水的二氧化钛光催化氧化实验。结果表明：在苯酚废水曝气量为0～3L/min的条件下,随着曝气量的增大,COD去除率先增大后减小;初始浓度不变,光照时间为1h的条件下, 调节pH值在3～11,苯酚废水COD去除率随着pH值的增大而减小,当pH值为11时, COD去除率又开始增 大,酸性条件比碱性条件下COD去除率高;随着二氧化钛投加量的增加,COD去除率增大,当二氧化钛投加量 为10g/L时,COD去除率反而降低,二氧化钛最佳投加量为3g/L;随着苯酚废水初始浓度由75mg/L增加至300mg/L,COD去除率由78.2％降低到58.1％;反应温度的改变对COD和TOC的去除率没有影响。     

TiO2固定膜光催化降解甲胺磷农药废水

采用自制的TiO2固定膜浅池反应器对经生化处理后的甲胺磷农药废水进行了降解试验。经处理后废水中的COD降为59．3mol/L、有机磷被全部降解为无机磷,达到《污水综合排放标准》（GB8978－1996）中的一级排放标准。     

纳米二氧化钛与玻璃深加工

一、纳米二氧化钛性能简介 纳米二氧化钛作为纳米材料当中的重要一簇,同样具备纳米材料一般具备的4个方面效应,即表面效应、量子尺寸效应、体积效应、宏观量子隧道效应。应用上主要表现为两种特性,一是光催化性,即在大于其带隙光照条件下,TiO2不仅能充分降解环境中的有害有机物,而且可氧化去除大气中低浓度的Nox、H2S等有毒气体,体现为比较高的光催化活性、高化学稳定性;二是超亲水和超亲油特性,TiO2表面经紫外光照射可诱发另一种反应,使其表面结构发生变化,从而使其表面与水的接触面减小到5度以下,甚至可达到0度,即水滴完…     

纳米TiO_2膜制备与光催化降解CHCl_3

采用溶胶法制备纳米TiO2 薄膜 ,其晶体为锐钛矿型。若加入PEG 2 0 0 0可使薄膜呈多孔状 ,并影响薄膜的透光率。纳米TiO2 薄膜对CHCl3 的光降解有很好的催化性能 ,而多孔状纳米TiO2 薄膜的催化性能更优 ,光催化条件下的CHCl3 分解率接近 90 %。     

Removal of Cu(II) and Cd(II) from aqueous solution by seafood processing waste sludge

Dried waste slurry generated in seafood processing factories has been shown to be an effective adsorbent for the removal of heavy metals from dilute solutions. Characterization of the sludge surface with scanning electron microscope and X-ray microanalyzer were carried out to evaluate the components on the sludge surface that are related to the adsorption of metal ions. Aluminum and calcium, as well as organic carbon are distributed on the surface of sludge. Alkalimetric titration was used to characterize the surface acidity of the sludge sample. The surface acidity constants, pKa1s and pKa2s, were 5.80 and 9.55, respectively. Batch as well as dynamic adsorption studies were conducted with 10(-5) to 5 x 10(-3) M Cu(II) and Cd(II). A surface complexation model with the diffuse layer model successfully predicted Cu(II) and Cd(II) removals in single metal solutions. Predictions of sorption in binary-adsorbate systems based on single-adsorbate data fits represented competitive sorption data reasonably well over a wide range of conditions. The breakthrough capacity found from column studies was different for each metal ion and the data reflect the order of metal affinity for the adsorbent material very well.     

Effects of titanium dioxide industry waste dumping on sea water chemistry

An investigation was made to determine the influence of the dumping of a 1000 ton day⁻¹, on the average, of acid-iron waste from the titanium dioxide industry into the shallow but turbulent Southern Bight of the North Sea. This waste contains some 20% sulfuric acid and 2% iron. After the passage of the barge that discharges 10 ton of waste min⁻¹ into its wake, the vertical and horizontal distributions of the pH, iron-concentration and turbidity were measured as a function of time. It appeared that a few seconds after the discharge and for a very brief period, the pH was down to approx. 4 and the Fe-concentration was 13 mg l⁻¹. More than 1 min after the discharge a pH below 6 and an iron-level above 3 mg l⁻¹ could not be detected anywhere. The measured factor for waste dilution by sea water, based on the observed acid and iron concentration in the waste and in the discharge track, were around 5000 after 5 min, 9000 after 10 min and 80,000 after 20 min. Before and long after the dumping, the total iron-concentration in this Southern Bight area was around 100 μg l⁻¹, but this high level might be due to natural causes.     

Improved AOX degradation in UV oxidative waste water treatment by dialysis with nanofiltration membrane

In this article, the wastewater treatment by UV oxidation with and without preceding desalination is compared. The influence of different chloride concentrations on the TOC degradation and AOX concentration is analyzed. Nanofiltration membrane dialysis is used to separate the chloride ions from wastewater. It is demonstrated that a reduction of the chloride concentration leads to a faster TOC degradation compared to the treatment of non-desalinated wastewater. Furthermore, the additional formation of AOX during the process could be avoided in effect leading to a significant degradation of native AOX.     

以废热水为热源的二氧化碳热泵热水器分析

提出了以废热水为热源的二氧化碳热泵热水器系统,给出了该系统的工作原理,借助EES计算软件,进行了不同工况下系统的性能分析,为系统的运行提供了参考。     

谈城市污水的再生利用

分析了我国水资源危机的原因 ,以北京市的中水应用为例 ,阐述了发展城市中水应用的必要性和重要性 ,提出应对水资源危机的主要对策     

Photocatalytic degradation of benzenesulfonate on colloidal titanium dioxide

Titanium dioxide-mediated photocatalyzed degradation of benzenesulfonate (BS) was investigated by monitoring chemical oxygen demand (COD), total organic carbon (TOC) content, sulfate concentration, pH as well as the absorption and emission spectral changes in both argon-saturated and aerated systems. Liquid chromatography-mass spectrometry analysis was utilized for the detection of intermediates formed during the irradiation in the UVA range (λ_max = 350 nm). The results obtained by these analytical techniques indicate that the initial step of degradation is hydroxylation of the starting surfactant, resulting in the production of hydroxy- and dihydroxybenzenesulfonates. These reactions were accompanied by desulfonation, which increases [H⁺] in both argon-saturated and aerated systems. In accordance with our previous theoretical calculations, the formation of ortho- and meta-hydroxylated derivatives is favored in the first step. The main product of the further oxygenation of these derivatives was 2,5-dihydroxy-benzesulfonate. No decay of the hydroxy species occurred during the 8-h irradiation in the absence of dissolved oxygen. In the aerated system much more efficient desulfonation and hydroxylation, moreover, a significant decrease of TOC took place at the initial stage. Further hydroxylation led to cleavage of the aromatic system, due to the formation of polyhydroxy derivatives, followed by ring fission, resulting in the production of aldehydes and carboxylic acids. Total mineralization was achieved by the end of the 8-h photocatalysis. It has been proved that in this photocatalytic procedure the presence of dissolved oxygen is necessary for the cleavage of the aromatic ring because hydroxyl radicals photochemically formed in the deaerated system too alone are not able to break the C-C bonds.     

Microanalysis of anionic surfactants in waste water by infrared spectroscopy

Infrared spectroscopy was applied to identify and determine microamounts of anionic surfactants contained in sewage or river waters. The surfactants tested were linear alkylbenzene sulfonate (LAS), branched alkylbenzene sulfonate (ABS), alpha olefine sulfonate (AOS), fatty alcohol sulfate (AS) and fatty alcohol ethoxy sulfate (AES).Anionic surfactants in waters were extracted by chloroform as methylene blue complexes and sulfate type surfactants, i.e. AS and AES were then removed by subsequent hydrolysis. Residual sulfonate type surfactants were first released from methylene blue complexes by ion exchange technique and then changed to sulfonyl chloride derivatives for infrared spectroscopy. Key bands for the identification of sulfonate type surfactants are 640, 618 and 524 cm⁻¹ for LAS, ABS and AOS, respectively. Sulfate type surfactants was calculated from the difference of methylene blue active substance contents before and after hydrolysis.     

ClO2预氧化去除水源水中微量酚类研究

针对微量酚类污染物在液氯消毒工艺中会产生氯酚并导致严重嗅味的问题,采用ClO2预氧化的方法去除水源水中的微量酚类,从而控制消毒过程中氯酚的形成。先通过静态烧杯试验,再用全自动微型移动式平台对试验参数进行动态模拟。结果表明,在苯酚质量浓度为280μg／L的条件下,ClO2对苯酚的去除效果基本能满足《生活饮用水卫生标准》（GB5749-2006）要求,苯酚去除率达到90％以上;从ClO2投加量及预氧化时间方面得出了最佳工艺参数,即ClO2投加量为0．6～1．0mg／L,预氧化时间为30～60s。     

合成锰氧化物氧化水中苯酚的研究

在实验室条件下制备出了合成锰氧化物(结构类似于δ-MnO2),研究了锰氧化物对水中微量苯酚的氧化效果,并对影响因素进行了分析.实验结果表明:合成锰氧化物对水中微量苯酚具有很好的氧化能力.在pH=3,合成锰氧化物投加量为10mg,反应720min时,合成锰氧化物对200mL质量浓度为5mg/L的苯酚去除率达到86.8%,随着pH值的升高,合成锰氧化物对苯酚的氧化能力逐渐降低,在pH=3时最大;一定范围内,随着合成锰氧化物投加量的增加以及苯酚初始浓度的增加,苯酚的氧化去除率也随之增加;合成锰氧化物对苯酚的氧化受环境中金属离子的抑制作用,其中,Na+、Ca2+、Mg2+离子的抑制效果较弱,而Pb2+、Mn2+等离子抑制作用较强,具体抑制效果为:Na+Ca2+≈Mg2+Zn2+Cu2+Ba2+Mn2+Pb2+.     

Separation of titanium dioxide from photocatalytically treated water by cross-flow microfiltration

This study focuses on the separation of titanium dioxide from water by cross-flow microfiltration (CMF) within wastewater treatment by photocatalysis using slurry reactor systems. The systematic studies have shown that the separation performance of TiO2 particles is strongly affected by cross-flow velocity, transmembrane pressure, feed concentration, pH of the suspension and ionic strength. An extreme sensitivity to pH and electrolyte concentration indicates the importance of interfacial effects in solid-liquid separation of TiO2 particles. Under optimal conditions, permeate fluxes of up to 1250 l m-2 h-1, approaching those of pure water, could be obtained with a polypropylene membrane which is not sensitive to abrasion. The obtained results makes TiO2 separation by cross-flow microfiltration attractive in solar-catalytic detoxification.