臭氧催化氧化降解煤化工高盐废水有机物的机理

研究了臭氧催化氧化降解煤化工高盐废水有机物的机理。实验采集了国内典型煤化工企业高盐废水,明确了水中盐离子的组成及含量;制备高盐性臭氧催化剂,研究了不同活性组分对臭氧催化氧化效率的影响,确定了最佳的臭氧催化剂;对臭氧催化剂开展表征分析,明确催化剂表观形貌、元素组成及负载情况;最后采用甲酸模拟水样,研究臭氧催化氧化作用方式、臭氧衰减率变化、羟基自由基（·OH）变化、H₂O₂变化及超氧自由基（·O₂^-）变化,明确臭氧催化氧化作用机理及反应历程。结果表明：煤化工高盐废水阳离子主要为钠离子,其次是钾离子、钙离子、镁离子;阴离子主要为氯离子、硫酸根,其次是硝酸根离子;通过研究不同活性组分对臭氧催化氧化效率确定最佳催化剂为SiO₂/Al₂O₃-Fe₂O₃。对催化剂开展表征分析发现：催化剂载体为硅铝复合氧化物,铁作为活性组分均匀负载于载体上。臭氧催化氧化降解机理研究发现：臭氧催化氧化过程遵从羟基自由基作用机理,O₃通过衰减产生羟基自由基,而催化剂的加入促进了·OH生成;反应过程中产生的H₂O₂量与·?OH有关,·?OH越多,H₂O₂产生量越多,但·O₂^-的产生与·OH没关系。     

臭氧高级氧化对某工业园区污水处理厂生化出水处理试验

传统污水处理厂的生化处理过程难以去除部分工业废水中的溶解性难降解有机物,往往需要添加深度处理单元对出水进行进一步处理,以保证达标排放。以某工业园区污水处理厂的生化出水为研究对象,进行臭氧氧化小试和中试试验,考察了以H₂O₂作为催化剂或市售臭氧催化剂下臭氧氧化对COD_Cr的去除效果。研究结果表明：在没有催化剂存在的条件下,臭氧与有机分子主要发生直接氧化作用,难以将有机污染物分子完全矿化至CO₂;添加催化剂后,臭氧分子在催化剂的作用下生成了具有强氧化性的·OH,对部分难与臭氧反应的有机分子具有无选择性的降解作用,促进了COD_Cr的去除。臭氧催化氧化技术虽然具有运行管理简单、无二次污染等优点,但由于其选择性较强,需要在工程应用前期需要进行充分的试验,以确保技术的可行性。     

Ag3PO4光催化-臭氧催化氧化协同降解苯酚

以Ag₃PO₄为光催化剂并通入臭氧构建了光催化-催化臭氧氧化协同体系，大幅度提高了对苯酚的降解效率。协同处理6 min后可将30 mg/L的苯酚溶液完全降解，在达到相同降解效率时，与单一氧化技术相比时间缩短了3倍。协同体系降解性能的提升源于臭氧的亲电特性，不仅加速了光生电荷的迁移，提升了光催化降解活性；同时还有效提高了臭氧利用效率，催化分解臭氧能产生更多的羟基自由基(·OH)，协同促进了苯酚的降解矿化性能。进一步通过猝灭实验验证了·OH是协同降解体系的主要活性物种，考察了臭氧浓度、催化剂投加量、苯酚浓度和酸碱性对降解效率的影响，探讨了光催化-臭氧催化氧化协同降解苯酚的降解机理。     

Co3O4催化臭氧氧化降解水中酮基布洛芬的研究

以Co(NO₃)₂·6H₂O和尿素为原料制备了9种Co₃O₄催化材料，考察了其对水中酮基布洛芬(KTP)的催化臭氧氧化降解效能。结果表明，与单独臭氧氧化相比，所制备的Co₃O₄对水中KTP的催化臭氧氧化降解率提高了12.0%～63.8%，且在n[Co(NO₃)₂·6H₂O]:n(尿素)=4:1、煅烧温度400℃下制备得到的Co₃O₄催化剂催化活性最高。SEM、XRD、FTIR、XPS、BET等表征分析显示，该Co₃O₄催化剂表面呈覆盖细小微粒的球状颗粒，晶相为立方相，且表面含有丰富的羟基，表面羟基密度为1.075×10^-5 mol/m²。机理研究证实，Co₃O₄对水中KTP的非均相催化臭氧氧化降解...     

Mg(OH)2及与Al3+离子共存时去除植酸的性能与机理研究

通过低浓度镁离子和氢氧根离子自然沉淀，低温4°C减慢合成速度来合成Mg(OH)₂，并研究其对于IHP的吸附去除作用和机理。研究结果表明：IHP在Mg(OH)₂表面的吸附热力学符合Freundlich模型，且吸附速率较快，在反应3 min时已达到平衡吸附量的75%。而且Mg(OH)₂对于IHP的吸附具有pH依赖性。对于其机理研究发现，IHP的吸附去除会促进Mg(OH)₂的溶解，Mg²⁺离子先释放进入环境中再被Mg(OH)₂重新吸附，从而促进IHP的进一步吸附。另外Mg(OH)₂与Al³⁺共存时对于IHP的去除具有协同作用，其作用效果大于两者单独作用效果的简单叠加。     

多级结构羟基硝酸铜纳米酶的制备及其对酚类污染物的降解

漆酶是一种多铜氧化酶,在空气条件下即可催化氧化多胺、多酚类有机物,被认为是水处理及土壤修复领域的绿色催化剂。纳米酶是一种具有酶催化活性的纳米材料,因其具有多功能性、低成本、高稳定性等优点,近年来引起广泛关注。因此,本文以尿素水解过程中产生的异氰酸根离子为模板剂,与Cu(NO₃)₂溶液反应制备具有漆酶活性的多级结构羟基硝酸铜[H-Cu₂(OH)₃NO₃]纳米酶。其催化活性是传统Cu(NO₃)₂与尿素水解法制备的羟基硝酸铜的1.85倍,其最大反应速率是漆酶的1.27倍。H-Cu₂(OH)₃NO₃纳米酶在不同pH、温度、储存时间和盐浓度条件下体现良好的催化稳定性。在重复利用12次后,保持58%的催化活性,体现出良好的重复利用性。而且H-Cu₂(OH)₃NO₃纳米酶具有降解土壤与地下水中常见的2,4-二氯苯酚、对...     

Fe2O3/改性沸石催化剂的制备及其催化臭氧氧化对氯苯酚

为了提高非均相催化臭氧氧化体系处理难降解有机废水的效率,分别以十六烷基三甲基溴化铵（CTMAB）改性的天然沸石和Fe(NO₃)₃·9H₂O溶液作为载体和活性组分前体,采用浸渍法制备Fe₂O₃/改性天然沸石催化剂（MNZ）,利用能谱仪（EDS）、扫描电镜（SEM）、傅里叶变换红外光谱仪（FTIR）、X射线衍射仪（XRD）、X射线光电子能谱仪（XPS）、N₂-吸附/脱附等方法分析催化剂的结构和组成,研究其催化臭氧氧化对氯苯酚的效果和催化机制。结果表明：Fe₂O₃/MNZ催化剂保持了天然沸石的表面结构。Fe₂O₃均匀负载在沸石表面,属于典型的分子筛结构,比表面积、孔容和孔径分别为12.776m²/g、0.042cm³/g和3.932nm。在对氯苯酚初始浓度为100mg/L、臭氧浓度为2.6mg/L、温度为25℃、pH为7.0±0.2的条件下,对氯苯酚和化学需氧量（COD）去除率分别为87.26%和48.83%。天然沸石与Fe₂O₃共同促进臭氧分解生成强氧化能力的羟基自由基（·OH）,提高了对氯苯酚的去除率,反应体系遵循羟基自由基作用机理。     

Cu2(NO3)(OH)3催化过硫酸盐降解苯酚

基于过硫酸盐的高级氧化工艺在高浓度含酚废水处理中引起了越来越多的关注。我们研究了Cu₂（NO₃）（OH）₃和过硫酸盐对于废水中苯酚的降解效果和机理。结果表明,Cu₂（NO₃）（OH）₃-过硫酸盐体系在较广泛的pH条件下（pH值为5.0~10.0）对苯酚的降解效率均较高。溶液中的总有机碳（TOC）分析表明,在pH值为8.0,1 g·L^-1过硫酸盐和1 g·L^-1 Cu₂（NO₃）（OH）₃条件下,该体系可在4 h内将初始浓度为100 mg·L^-1的苯酚完全矿化而没有产生二次污染。猝灭剂实验和电子顺磁共振（EPR）分析进一步证实Cu₂（NO₃）（OH）₃-过硫酸盐体系中的主要氧化物种是O₂^·-、SO₄^·-和¹O₂。     

可见光下Cu2O/TiO2催化臭氧氧化头孢曲松钠性能研究

抗生素是治疗各种传染病的常用药物,但残留在水环境中的抗生素会对生态系统造成威胁。因此,探索去除水环境中抗生素的有效方法具有重要意义。由于光催化臭氧氧化技术可以高效降解和矿化水体中的污染物,该技术受到广泛关注。本工作通过浸渍-化学还原法制备Cu₂O/TiO₂复合材料并将其作为可见光催化臭氧氧化头孢曲松钠(CRO)的催化剂。利用X射线衍射仪(XRD)、傅里叶变换红外光谱仪(FT-IR)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、比表面积分析仪(BET)和紫外-可见漫反射光谱仪(UV-Vis DRS)对Cu₂O/TiO₂形貌结构和光学性能进行表征,考察了Cu₂O/TiO₂配比、Cu₂O/TiO₂投加量、臭氧浓度、头孢曲松钠初始浓度、溶液初始pH值等因素对可见光催化臭氧氧化头孢曲松钠的影响。结果表明,Cu₂O对TiO₂的掺杂改性使材料孔容和平均孔径增大,能带宽度减小,...     

过渡金属氧化物催化臭氧化在水处理中的应用

介绍了近年来均相和异相催化臭氧化去除水中有机物的研究.过渡金属离子能提高有机物的去除效率,但是均相催化臭氧化带来了后续金属离子的去除问题,因此金属氧化物作为催化剂的异相催化臭氧化具有更好的应用前景,重点介绍了锰氧化物、钛氧化物催化臭氧化降解水中有机物的研究现状.     

Relationship between the structure of Ru/CeO2 catalysts and their activity in the catalytic ozonation of succinic acid aqueous solutions

Two Ru/CeO₂ catalysts were used for the study of the catalytic ozonation of aqueous solutions of succinic acid (SA). These catalysts were prepared either by impregnation (I) or by acid exchange (AE). The objectives were (1) to determine the efficiency towards the oxidation of the organic molecule in relation to the catalysts characterization, and (2) to examine the modifications of the structure induced by ozonation. For each catalyst, two experimental conditions of catalyst and succinic acid concentrations were studied. The diluted conditions ([SA]₀=1 mM, weight_cata=0.8 g/l) were applied for the study of the behavior of the catalysts during successive uses. The efficiency was also studied for higher initial concentrations ([SA]₀=5 mM, weight_cata=3.2 g/l). Under both conditions the best efficiency was obtained with the impregnated catalyst.

Transmission electronic microscopy analyses indicated that before ozonation of SA, ruthenium was distributed within the whole volume of the grain of CeO₂ for the AE catalyst, and included only in an external layer for the I catalyst. The size of the particles determined by X-ray diffraction (XRD) was around 3.5 nm for Ru and in the range 10–75 nm for CeO₂. In most cases, the catalytic ozonation induced Ru sintering with the formation of clusters. After four successive ozonation experiments the AE catalyst efficiency was significantly decreased and the structure totally disorganized.     

Ni-olivine catalysts prepared by thermal impregnation: Structure, steam reforming activity, and stability

Ni-olivine catalysts prepared by thermal impregnation are candidate materials for in-bed catalytic tar removal during fluidized bed biomass gasification. The present work examined the structure and surface properties of the Ni-olivine catalysts prepared by thermal impregnation following preparation, during reduction by in-situ techniques, and following naphthalene-steam reforming in simulated biomass derived syngas. Catalysts were characterized by BET surface area, laser Raman spectroscopy (LRS), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). During the preparation, secondary phases containing Mg (i.e., (Mg,Fe)₃Si₂O₅(OH)₄ and MgFe₂O₄) reacted to form an olivine phase enriched in Mg and either MgO or Mg-enriched (Mg,Ni)O. The presence of excess steam in the naphthalene-steam reforming appeared to limit coking and also caused behavior to be different than was observed under reducing conditions. Post-reaction characterization indicated the loss of a metallic phase through a possible alloying process and the exchange of Fe for Mg in the olivine structure. Either can potentially explain the high coke resistance of the Ni-olivine catalysts prepared by thermal impregnation compared to Ni-olivine catalysts prepared by incipient wetness impregnation or the olivine support. Finally, the properties of the olivine catalysts with and without Ni were compared through activity for methanol- and ethylene-steam reforming.     

Ozonation of alachlor catalyzed by Cu/Al2O3 in water

The Cu/Al₂O₃ catalyzed ozonation for degrading an endocrine disruptor—alachlor in water was investigated. The Cu/Al₂O₃ powders were coated on a cordierite honeycomb column, which was taken as the reactor of catalytic ozonation of alachlor. Additional uncatalyzed experiments were carried out and the results were compared to those of the catalytic runs.

The experimental results demonstrated that Cu/Al₂O₃ was a very effective catalyst for ozonation of alachlor. The removal rate of alachlor in total organic carbon (TOC) with ozonation in the absence of Cu/Al₂O₃ was only above 20% in 180 min, while the reduction of totle organic carbon (TOC) in the presence of Cu/Al₂O₃ was more than 60%. Correspondingly, more inorganic ions created and less by-products produced in the Cu/Al₂O₃ catalyzed ozonation than in the unanalyzed process. These results indicated that the use of Cu/Al₂O₃ substantially enhanced the mineralization of alachlor in ozonation. The EPR experiments verified that more √OH radicals generated in the Cu/Al₂O₃ catalyzed ozonation could bring on a higher alachlor removal rate.     

Olivine catalysts for methane- and tar-steam reforming

The removal of tar and lower hydrocarbons is a vital technological barrier hindering the development of biomass gasification. The present work evaluates four olivine catalysts (three untreated of different origin and one calcined) for lowering the amount of these compounds in biomass derived syngas by reforming model compounds (naphthalene, toluene, and methane). Treatments prior to reaction were shown to largely impact the catalytic activity and physiochemical properties of the olivine catalysts depending on its origin. The formation of free Fe phases following decomposition of a Fe-bearing serpentine phase ((Mg,Fe)₃Si₂O₅(OH)₄) near the surface of untreated olivine catalysts proved most important for facilitating higher activity compared to olivine catalysts with little or no serpentine phase initially. The most active catalyst was efficient at naphthalene removal (90% conversion at 800 °C), but more active catalysts are needed for applications where methane removal is required. Additionally, carbon deposition during naphthalene-steam reforming as well as Fe clustering during naphthalene-steam reforming and exposure to reducing conditions suggested stability may be a liability.     

钙镁氧化物及氢氧化物脱除SO3协同防治催化剂低温失活

在实验室中试台架上,开展了Ca(OH)₂、CaO、Mg(OH)₂和MgO四种碱基吸附剂粉体喷射脱除烟气SO₃的实验,研究了碱基吸附剂脱除烟气SO₃的影响因素,探究了碱基吸附剂脱除SO₃技术对选择性催化还原（SCR）催化剂硫酸氢铵失活温度的影响。采用比表面积法（BET）、傅里叶红外光谱（FTIR）等手段对吸附剂进行表征,以判断吸附产物和吸附机理。结果显示：碱基氢氧化物吸附剂的SO₃脱除效果优于碱基氧化物吸附剂;Mg基吸附剂优于Ca基吸附剂;当烟气中SO₃浓度为35μL/L时,Mg(OH)₂含量为600mg/m³时具有最高的SO₃脱除效率,达到95%左右。对低温失活后的SCR催化剂进行FTIR表征证实了催化剂表面硫酸氢铵的生成。此外,通过碱基吸附剂降低烟气中SO₃浓度后,SCR催化剂在低温时的失活得到了显著缓解,可明显降低SCR催化剂的硫酸氢铵失活温度约20℃,有助于挖掘机组调峰深度。     

Magnéli phases TinO2n−1 as novel ozonation catalysts for effective mineralization of phenol

Magnéli phases Ti_nO_2n-1 have been demonstrated as promising environmentally friendly materials in advanced oxidation processes. In this study, Magnéli phases Ti_nO_2n-1 have been used as catalysts for the ozonation of phenol in aqueous solution for the first time. The materials exhibited excellent catalytic ozonation activities both in phenol degradation and mineralization. When Ti₄O₇ was added, the reaction rate was six-fold higher than that of with ozone alone, while the total organic carbon removal rate was substantially elevated from around 19.2% to 92%. By virtue of the good chemical stability of the materials, a low metal leaching of less than 0.15 mg·L^-1 could effectively avoid the secondary pollution by metal ions. Radical quenching tests revealed ·O₂^- and ¹O₂ to be active oxygen species for phenol degradation at pH 5. As semiconductor catalysts, Ti_nO_2n-1 materials show electronic transfer capability. Ozone adsorbed at B-acid sites of the catalyst surface can capture an electron from the conversion of Ti(Ⅲ) to Ti(IV), and is thereby broken into the active oxygen species. It was interesting to observe that Ti_nO_2n-1 exhibit better catalytic activity for phenol degradation and mineralization with lower n value. The difference in electrical conductivity can be considered as a major factor for the catalytic performances. More highly conductive catalysts show a faster electron-transfer rate and better catalytic activity. Thus, significant evidences have been obtained for a single-electron-transfer mechanism of catalytic ozonation with Magnéli phases Ti_nO_2n-1.     

Mg(OH)2引入方式对纸浆过氧化氢漂白工艺的影响

引言制浆造纸工业是废水和污染物排放的重要源头之一。传统含氯漂白会产生多种难降解、对环境具有高危害的含氯有机化合物,因此它们正在被过氧化氢漂白等无氯漂白工艺所取代。纸浆中的过渡金属离子可催化过氧化氢无效分解并形成对纤维素破化性强的自由基,因此常采用漂前酸洗、螯合及漂白保护剂等来消除和抑制过渡金属离子的影响。而如何使保护剂的功效得到更好的发挥,是     

改性氢氧化镁的制备及在HDPE中的应用

以低品位菱镁矿为原料,γ-(甲基丙烯酰氧)丙基三甲氧基硅烷(KH570)为改性剂,通过蒸氨-沉镁改性-水热过程制备改性氢氧化镁[KH570-Mg(OH)₂],改性剂在Mg(OH)₂生成体系中加入。采用吸油值、活化指数、红外光谱(FTIR)、X射线衍射(XRD)等手段对改性结果进行表征,在改性时间为60min,改性剂用量为2%,并进行水热处理工艺制备的Mg(OH)₂改性效果最好,改性后Mg(OH)₂活化指数达到了98.75%,吸油值为53.05 mL/100g,接触角为149°。整个工艺连续且可循环,为制备疏水性Mg(OH)₂工业生产提供实验基础。并将改性前后的Mg(OH)₂应用于高密度聚乙烯(HDPE),测试其阻燃和力学性能,结果表明,KH570-Mg(OH)₂添加量为40%时,HDPE/KH570-Mg(OH)₂复合材料的氧指数为29.5%,达到阻燃级别,拉伸强度为18.40 MPa,断裂伸长率为217.11%...     

O3 based advanced oxidation for ibuprofen degradation

The degradation of the anti-inflammatory ibuprofen (IBP) was evaluated by several advanced oxidation processes. IBP was treated by single ozonation and oxidation with hydrogen peroxide (H₂O₂), as well as a combination of these treatments. In order to improve the efficiency, the presence of catalysts such as original carbon nanotubes, labelled as CNT, and iron oxide supported on carbon nanotubes, named as Fe/CNT sample, was considered. The evolution of IBP degradation, mineralization and toxicity of the solutions was assessed. The formation of intermediates was also monitored. In the non-catalytic processes, IBP was faster removed by single ozonation, whereas no significant total organic carbon (TOC) removal was achieved. Oxidation with H₂O₂ did not present satisfactory results. When ozone and H₂O₂ were combined, a higher mineralization was attained (70% after 180 min of reaction). On the other hand, in the catalytic processes, this combined process allowed the fastest IBP degradation. In terms of mineralization degree, the presence of Fe/CNT increases the removal rate in the first hour of reaction, achieving a TOC removal of 85%. Four compounds were detected as by-products. All treated solutions presented lower toxicity than the initial solution, suggesting that the released intermediates during applied processes are less toxic.     

In situ synthesis of hydrophobic magnesium hydroxide nanoparticles in a novel impinging stream-rotating packed bed reactor

Hydrophobic Mg(OH)_2nanoparticles were successfully synthesized via an in situ surface modification method in a novel impinging stream-rotating packed bed(IS-RPB) reactor using oleic acid(C_(17)H_(33)COOH, OA) as a surface modifier, magnesium chloride hexahydrate in the presence of ethanol as a precursor, and sodium hydroxide as a precipitant. The products were characterized by Fourier transform infrared spectroscopy(FTIR), Field emission scanning electron microscopy(FESEM), X-ray diffraction(XRD), and thermogravimetry-differential scanning calorimetry(TG-DSC). Compatibility with organic solutions was determined by sedimentation tests. The prepared nanoparticles exhibited regular hexagonal lamella with an average diameter of 30 nm when OA is added to the reaction system; this result indicates that OA regulates the morphology of the Mg(OH)_2nanoparticles.XRD revealed that the high-purity Mg(OH)_2product presents a brucite structure, and the I_(001)/I_(101) of hydrophobic Mg(OH)_2(0.86) was higher than that of the blank Mg(OH)_2(0.63). FTIR analysis showed that OA bonded to the surface of the Mg(OH)_2. Compared with the blank Mg(OH)_2product, the product obtained through the proposed method possesses excellent hydrophobic properties, including a high water contact angle of 101.4° and good compatibility with liquid paraffin. TG-DSC analysis indicated that the total percentage of mass loss of hydrophobic Mg(OH)_2(40.88%) was higher than that of the blank Mg(OH)_2product(33.18%). The in situ surface modification method proposed in this work presents potential use in the large-scale production of Mg(OH)_2nanoparticles.