UV/Fenton氧化法对苯酚氧化效果的实验研究

研究UV/Fenton氧化法中各个因素对降解水中苯酚的影响,确定UV/Fenton法处理苯酚废水的工艺条件。保持UV/Fenton体系的基准条件不变,通过改变H2O2浓度、n(Fe2+)∶n(H2O2)、废水初始pH值等实验条件,考察这些因素对UV/Fenton法处理苯酚废水效果的影响。结果表明:UV/Fen-ton氧化法对苯酚废水有较好的去除效果和较高的反应速率。当废水初始pH值为3.0时,经30 min的反应,苯酚去除率达到99%,COD去除率达到86%。但是苯酚废水COD去除率滞后于苯酚去除率。UV/Fenton法能够在较短的时间内去除苯酚和COD,H2O2浓度、n(Fe2+)∶n(H2O2)对处理效果影响较大,H2O2浓度决定苯酚去除率和COD去除率,而n(Fe2+)∶n(H2O2)是影响降解速率的主导因素。     

ZVI/Fe2+/H2O2类Fenton法深度处理烟草薄片废水

采用零价铁(ZVI)/Fe2+/H2O2类Fenton法深度处理造纸法烟草薄片废水(二级生化出水),探讨了反应时间、初始pH、Fe2+浓度、H2O2浓度和ZVI质量浓度对COD和色度去除效果的影响。结果表明,当反应时间为60 min、初始pH为5.0、Fe2+浓度为1.0 mmol/L、ZVI质量浓度为2.0 g/L、H2O2浓度10 mmol/L时,处理后色度为84 C.U.、脱色率为95.5%;COD为73 mg/L,COD去除率为80.4%。与传统Fenton法对比发现,ZVI/Fe2+/H2O2类Fenton法具有可在弱酸性条件下(pH=5.0)使用、总铁需求量少(减少26%)和产泥量少(减少2/3左右)的优点。     

Fe/C微电解—Fenton氧化组合工艺处理松节油加工废水

采用Fe/C微电解—Fenton氧化法处理松节油加工废水,Fe/C微电解单元主要研究了铁屑投加量、铁炭比、pH对处理效果的影响;Fenton氧化单元主要研究了H2O2投加量、超声、UV对Fenton处理效果的影响。结果表明:在铁屑投加量为100 g/L,铁炭比为1,pH为2时,COD、色度的去除率达到84.2%、96%,B/C从0.12升高到0.41;在H2O2投加量为8 mL,pH为3,超声功率为100 W的条件下,COD去除率达到98.5%,B/C从0.41提高到0.65,最终处理后废水COD≤100 mg/L,色度≤5。     

UV/Fenton氧化与生化组合技术处理磺化泥浆体系钻井废水

采用UV/Fenton氧化和生化组合技术处理磺化泥浆体系钻井废水.当用UV/Fenton氧化单独处理时,其合适的条件为n(H2O2):n(Fe2 )=40:1,pH为3～5.采用B/C和生化呼吸曲线两种方法评价了UV/Fenton氧化后水样的可生化性,结果表明钻井废水经氧化后可生化性大幅提高.采用UV/Fenton氧化和生化组合技术处理钻井废水,在预氧化阶段投加0.60th mg·L-1(理论投加量)和1.0Qth mg·L-1双氧水时,COD总去除率分别为82.5%和87.3%,出水可达国家一级排放标准.组合技术和单独氧化法相比,既提高了处理效率,又大大节省了双氧水的投加量.     

UV/Fenton降解拟除虫菊酯农药废水的研究

主要探讨了UV/Fenton联合工艺处理拟除虫菊酯农药废水的可行性和规律性,考察了在UV/Fenton降解拟除虫菊酯农药废水的过程中,pH、H2O2加入量、m(H2O2)∶m(FeSO4)、降解时间和紫外灯光强等因素对降解效果的影响。试验结果表明:对初始COD为4 700 mg/L的拟除虫菊酯农药废水,在pH=4,H2O2浓度为8 mmol/L,m(H2O2)∶m(FeSO4)=7∶1的条件下,200 mL废水用14 W(相当于70 W/L)紫外灯照射3.0 h后,COD去除率可达51.32%。     

基于铜渣的类Fenton体系处理H酸废水的研究

采用铜渣与双氧水构成类Fenton体系处理H酸废水,考察了铜渣投加量、双氧水投加量、铜渣粒径和初始pH等因素对处理效果的影响。结果表明,在n(H2O2)∶m(COD)=55 mmol/g、n(H2O2)∶m(铜渣)=10 mmol/g和初始pH=3的条件下,反应180 min,COD及TOC去除率分别为70%和40%,比其他矿物类Fenton体系对H酸废水的处理效果有明显改善。铜渣在酸性条件下是H2O2氧化有机污染物的有效催化剂,有工业应用可能性。     

Fenton试剂预处理高色度有机化工废水的研究

以Fenton试剂处理兰州某化工厂有机废水。结果表明,Fenton反应的最佳操作条件为:H2O2投加量为0.15 mol/L,FeSO4投加量为4 mmol/L,初始pH为3,反应时间90 min。在最佳工艺条件下,有机废水色度去除率达98%以上,出水呈无色,COD Cr去除率达80%以上,同时出水B/C值大幅提高,达到0.49,预处理效果良好,有利于进一步生化处理。     

Fenton法处理模拟偶氮染料废水的研究

采用Fenton法对模拟偶氮染料废水进行了处理。考察了废水初始pH值、H2O2和Fe2＋投加量、反应时间及反应温度等对模拟染料废水COD去除率的影响。实验结果表明,在甲基红的初始浓度为200mg.L-1,初始pH值为3.0,H2O2和Fe2＋投加量分别为20mmol.L-1和1mmol.L-1,反应温度为50℃,反应时间为60min的条件下,废水中COD的去除率可达83.5%。     

Fenton-铁氧体法联合工艺处理络合电镀废水

采用Fenton-铁氧体法联合工艺处理含铜、镍的络合电镀废水。探讨了Fenton法破络反应初始pH、初始H2O2质量浓度,Fe2+与H2O2的质量比和反应温度对COD去除率的影响,研究了铁氧体法处理时pH、反应温度、Fe与金属离子的质量比和曝气速率等对处理效果的影响。结果表明,在初始pH=3、初始H2O2质量浓度为3.33g/L、m(Fe2+)/m(H2O2)=0.1、温度25°C的最优Fenton氧化条件下,对废水进行Fenton氧化处理60min,COD去除率高达73.4%。铁氧体法处理的最优工艺条件为:沉淀pH=11,曝气流量25mL/min,Fe与废水中金属离子的质量比为10,反应温度50°C,曝气接触时间60min。在此条件下废水中镍离子和铜离子的去除率分别达到99.94%和99.81%,均达标排放。另外,沉淀污泥的构相分析表明,在最佳工艺条件下所得沉淀物含铁氧体NiFe2O4、Fe3O4等。     

UV/Fenton处理磺化泥浆体系钻井废水

采用UV/Fenton氧化处理磺化泥浆体系钻井废水,考察了H2O2和Fe2 物质的量比、H2O2投加量和pH值等对废水处理的影响.结果表明,UV/Fenton氧化不仅能有效去除钻井废水中的有机污染物,还可提高钻井废水的可生化性.随着H202投加量的增加,有机污染物去除率也相应的提高.当H2O2投加量为理论值的1.5倍(1.5 Qth)时,反应180 min,化学需氧量(COD)可从586 mg/L降到90 mg/L,去除率达到84.6%,出水COD符合国家一级排放标准;当H2O2投加量为0.6 Qth时,反应30 min,生化需氧量和化学需氧量的比值(BOD/COD)可从0.03提高到0.45.增大Fe2 投加量可提高有机污染物降解速率,但不能增加COD的去除率.反应适宜的pH值为3～5.建立了有机污染物降解动力学模型,模型和实验结果符合较好.     

Self-organized nano-crystallisation of BaF2 from Na2O/K2O/BaF2/Al2O3/SiO2 glasses

In glasses with the compositions (100 ? x)(2Na₂O·16K₂O·8Al₂O₃·74SiO₂)xBaF₂ (with x = 0 to 6), the glass transition temperature decreases with increasing BaF₂-concentration. Samples with x = 6 were thermally treated at temperatures in the range from 500 to 600 °C for 5–160 h. This leads to the crystallisation of BaF₂. The quantity of crystalline BaF₂ increases with increasing time of thermal treatment, while the mean crystallite size remains constant within the limits of error. The glass transformation temperature of partially crystallised samples increases with increasing crystallisation time and approaches a value equal to the temperature, at which the samples were treated. This is explained by the formation of a highly viscous layer enriched in SiO₂ which is formed during crystallisation. This layer acts as a diffusion barrier and hinders further crystal growth.     

The System Na2O-CaO-SiO2-H2O

A portion of the quaternary phase diagram for Na₂O-CaO-SiO₂-H₂O has been constructed. Plotting concentrations as their 10th roots allows compounds having solubilities which differ by several orders of magnitude to be represented on a single diagram. The compositional relationships among sodium-substituted calcium silicate hydrate, calcium-substituted sodium silicate hydrate, calcium bydroxide, a quaternary compound of approximate composition 0.25Na₂O · CaO · SiO₂· 3H₂O, sodium hydroxide monohydrate, and miscellaneous sodium silicate hydrates are presented. The quaternary diagram constructed shows the quaternary compound to exist in equilibrium with sodium-substituted calcium silicate hydrate and calcium hydroxide. Conditions in concrete pore solutions which favor the formation of this quaternary compound may also favor the occurrence of the alkali-silica reaction.     

复合固体超强酸SO42-/ZrO2-Al2O3催化合成乳酸正丁酯的研究

合成了几种不同Zr、Al原子比的SO42-/ZrO2-Al2O3复合固体超强酸,将其用于催化乳酸与正丁醇的酯化反应,均有较好的催化活性,尤以ZrAl=12的催化效果最好,经济性优于ZrO2超强酸催化剂.其最佳反应条件为酸醇摩尔比为13,催化剂用量为乳酸质量的10%,反应时间2～2.5h,酯化率达96.9%.该催化剂具有制备容易、催化活性高、不污染环境、可重复使用的优点.     

Prediction of Immiscibility Boundaries of the Systems K2O-SiO2, K2O-Li20-SiO2, K20-Na2O-Si02, and K2O-BaO-SiO2

In earlier work, a prediction method of the immiscibility boundary of a ternary silicate glass system was developed involving two known binary immiscibility boundaries and a measured immiscibility temperature of one ternary glass composition. In the present work, the method is extended to the case where one of the two binary immiscibility boundaries is not known and is applied as an example to ternary silicate systems containing K₂O. First, the immiscibility boundary of the system K₂O-SiO₂ is estimated by measuring the immiscibility temperatures of three glasses in the system K₂O-Li₂O (or Na₂O)-SiO₂. Using this result the immiscibility boundaries of the systems K₂O-Li₂O-SiO₂, K₂O-Na₂O-SiO₂, and K₂O-BaO-SiO₂ are estimated. The results agree reasonably well with the experimentally determined immiscibility temperatures at selected compositions.     

Some Properties of the System Na2O-NaF-B2O2-H2O

It was first shown that the enamel slips which have the best suspnding characteristics contain equal amounts of Na₂O and B₂O₃ and at least a moderate amount of NaF. The solubilities of mixtures of Na₂O, NaF, and B₂O₃ were then investigated. The pH of these solutions and the primary crystalline phases separating on evaporation also were determined. The solubility data obtained at room temperature were summarized. When the solutions were evaporated, NaF was the first crystalline phase to separate from a large proportion of the mixtures investigated. It was concluded that the desirable handling characteristics of enamels whose mill liquors contain the proper proportion of Na₂O, NaF, and B₂O₃ are not due to the formation of complex salts but to the following combination of properties: (1) the presence of salts with a moderate solubility which changes very slightly with temperature, (2) a moderate pH of about 10 in a probably well-buffered solution, (3) a relatively stable crystalline material, NaF, as a primary phase, and (4) a secondary phase which crystallizes slowly with relatively little shrinkage.     

固体超强酸SO^2—4／TiO2催化合成尿囊素的研究

用固体超强酸SO42/TiO2为催化剂,以尿素和乙醛酸为原料合成了尿囊素。得到最佳条件为TiO2在1mo1·L-1H2SO4溶液中浸渍12h,再在600℃焙烧3h;尿素与乙醛酸摩尔比3.51,催化剂9％,时间3h,温度72℃～75℃,产率达57.4％。     

Photocatalytic activity of Cu2O/TiO2, Bi2O3/TiO2 and ZnMn2O4/TiO2 heterojunctions

Cu₂O/TiO₂, Bi₂O₃/TiO₂ and ZnMn₂O₄/TiO₂ heterojunctions were studied for potential applications in water decontamination technology and their capacity to induce an oxidation process under VIS light. UV–vis spectroscopy analysis showed that the junctions-based Cu₂O, Bi₂O₃ and ZnMn₂O₄ are able to absorb a large part of visible light (respectively, up to 650, 460 and 1000 nm). This fact was confirmed in the case of Cu₂O/TiO₂ and Bi₂O₃/TiO₂ by photocatalytic experiments performed under visible light. A part of the charge recombination that can take place when both semiconductors are excited was observed when a photocatalytic experiment was performed under UV–vis illumination. Orange II, 4-hydroxybenzoic and benzamide were used as pollutants in the experiment. Photoactivity of the junctions was found to be strongly dependent on the substrate. The different phenomena that were observed in each case are discussed.     

Crystallization of zeolite L from Na2O-K2O-Al2O3-SiO2-H2O system

Zeolite L powder was prepared from the substrate mixture of Na₂O-K₂O-Al₂O₃-SiO₂-H₂O system at temperatures of 373-443 K. In order to investigate the factors which influence the synthesis outcome, a reference system which yields zeolite L in a reproducible manner was chosen and subjected to controlled changes in synthesis parameters. The crystalline zeolite L samples obtained were characterized by elemental chemical analysis, X-ray diffraction (XRD), and scanning electron microscopy (SEM). It was established that phase purity, morphology, and the size of crystals of crystalline product were affected by molar ratios of the substrate, such as SiO₂/Al₂O₃, (K₂O+Na₂O)/SiO₂, Na₂O/(K₂O+Na₂O), and H₂O/(K₂O+Na₂O). Amorphous silica powder (Zeosil) was the preferred silica source, and the crystallization rate was promoted by introducing gel aging, seeding, and rapid heating rate.     

SELECTIVE CARBON MONOXIDE OXIDATION IN H2-RICH GAS STREAM OVER Co3O4/CeO2/ZrO2, Ag/CeO2/ZrO2, AND MnO2/CeO2/ZrO2 CATALYSTS

Activity and selectivity of selective CO oxidation in an H₂-rich gas stream over Co₃O₄/CeO₂/ZrO₂, Ag/CeO₂/ZrO₂, and MnO₂/CeO₂/ZrO₂ catalysts were studied. Effects of the metaloxide types and metaloxide molar ratios were investigated. XRD, SEM, and N₂ physisorption techniques were used to characterize the catalysts. All catalysts showed mesoporous structure. The best activity was obtained from 80/10/10 Co₃O₄/CeO₂/ZrO₂ catalyst, which resulted in 90% CO conversion at 200°C and selectivity greater than 80% at 125°C. Activity of the Co₃O₄/CeO₂/ZrO₂ catalyst increased with increase in Co₃O₄ molar ratio.