Fe2+/Mn2+活化亚硫酸盐降解盐酸土霉素的机理研究

盐酸土霉素常被用于治疗畜禽疾病,但是它不能被畜禽完全代谢,残留的盐酸土霉素进入水体危害水环境的健康。铁锰作为常见的过渡金属,通常以二价态活化亚硫酸盐来降解有机污染物,反应条件温和、操作简单,但是单独的二价铁与二价锰氧化还原电势低,活化亚硫酸盐效果较差。本研究采用Fe²⁺/Mn²⁺共活化Na₂SO₃降解水中的盐酸土霉素,考察药剂用量、pH、溶解氧、氯离子、碳酸根及腐殖酸对Fe²⁺/Mn²⁺/Na₂SO₃体系降解盐酸土霉素的影响;通过焦磷酸盐实验、自由基淬灭实验和EPR实验分析Fe²⁺/Mn²⁺/Na₂SO₃体系中的活性物种;利用紫外可见光谱、傅里叶红外光谱、气相色谱-质谱联用仪识别盐酸土霉素的官能团及其降解中间产物的变化,推断盐酸土霉素的降解途径。结果表明：当Fe²⁺/Mn²⁺/Na<...     

电化学高级氧化对HEDP的降解效能研究

羟基亚乙基二膦酸（HEDP）是典型的有机膦缓蚀阻垢剂,广泛存在于工业水处理系统中,其常规生物降解率低于5%,已成为工业废水处理回用和外排的制约因素。为此,探索了电化学高级氧化法对HEDP的降解效能,考察了电流密度、Na₂SO₄浓度、pH、温度及溶液流速等关键参数对HEDP降解率的影响;利用电子自旋共振测试,自由基猝灭方法和HEDP降解动力学探讨了HEDP的降解机制。结果表明,电流密度为30 mA/cm²,电解质Na₂SO₄浓度为0.1 mol/L,pH=11,温度为30℃,溶液流速为500 ml/min时HEDP降解率最高,90 min内可达99.7%;研究采用的电化学高级氧化体系产生羟基自由基（·OH）和硫酸根自由基（SO{}_{\mathrm{4}}^{-}·）,仅·OH可以降解HEDP,·OH与HEDP的反应速率常数k_•OH,HEDP=（4.28±0.24）×10⁸ L/（mol·s）。     

电化学高级氧化对HEDP的降解效能研究

羟基亚乙基二膦酸（HEDP）是典型的有机膦缓蚀阻垢剂,广泛存在于工业水处理系统中,其常规生物降解率低于5%,已成为工业废水处理回用和外排的制约因素。为此,探索了电化学高级氧化法对HEDP的降解效能,考察了电流密度、Na₂SO₄浓度、pH、温度及溶液流速等关键参数对HEDP降解率的影响;利用电子自旋共振测试,自由基猝灭方法和HEDP降解动力学探讨了HEDP的降解机制。结果表明,电流密度为30 mA/cm²,电解质Na₂SO₄浓度为0.1 mol/L,pH=11,温度为30℃,溶液流速为500 ml/min时HEDP降解率最高,90 min内可达99.7%;研究采用的电化学高级氧化体系产生羟基自由基（·OH）和硫酸根自由基（SO{}_{\mathrm{4}}^{-}·）,仅·OH可以降解HEDP,·OH与HEDP的反应速率常数k_•OH,HEDP=（4.28±0.24）×10⁸ L/（mol·s）。     

多缺陷MoS2纳米片对诺氟沙星的压电催化降解性能

通过调节Mo和S物质的量比,采用水热法合成多缺陷MoS₂纳米片,利用SEM和XRD对样品的形貌和结构进行表征,并以诺氟沙星为目标污染物评估样品的压电催化性能。结果表明,与无缺陷MoS₂相比,多缺陷MoS₂表现出优异的压电催化活性。在超声辐照下,Flaws MoS₂(1∶5)纳米片11 min内对诺氟沙星的降解率达99.69%,降解速率常数为6.78 min^-1。多缺陷MoS₂纳米片优异的压电催化性能主要归因于应变诱导的压电场引起的电子-空穴对的高效分离。活性物质捕获实验表明,羟基自由基(·OH)是降解诺氟沙星的主要活性氧物种。此外,多缺陷MoS₂纳米片的超高降解效率可应用于实际的环境修复。     

纳米管阵列光催化剂研究进展

TiO₂纳米管阵列以其优异的性能成为很有发展前景的新型纳米结构材料。综述了目前制备TiO₂纳米管阵列的3种方法,即模板合成法、水热合成法和阳极氧化法。阐述了提高TiO₂纳米管阵列的光催化活性常采用的改性方法,包括贵金属沉积、金属离子掺杂、非金属掺杂和半导体复合以及TiO₂纳米管阵列在染料敏化太阳能电池、光解水制氢、光催化降解有机污染物和气敏传感材料等领域的应用研究进展,提出通过改进制备工艺和改性方法制备高性能的TiO₂纳米管阵列光催化剂是未来主要的研究方向。     

阵列型TiO2纳米管光催化降解VOCs性能

通过二次阳极氧化电化学方法制备纳米孔/纳米管复合结构的阵列型TiO₂纳米管（2-step TiO₂ NTs）,实验证明这种结构的TiO₂ NTs对大气中的挥发性有机化合物（volatile organic compounds,VOCs）有着十分优异的降解效果。本文通过气态甲醇的光催化降解来评估比较一次氧化生成的TiO₂纳米管（1-step TiO₂ NTs）和2-step TiO₂ NTs的催化效果。实验结果表明,二次阳极氧化电化学方法所生成的TiO₂ NTs的纳米结构对光致电荷的产生有着十分重要的推动作用。之所以2-step TiO₂ NTs的纳米孔/纳米管复合结构能够显著提高VOCs的降解效率,是由于这种特殊的结构能够更加有利于电子的传递,同时能够有效地抑制光生电子和空穴的复合。最后,通过实验数据阐述了2-step TiO₂ NTs光催化活性的增强机理,这种新结构显示出更小的带隙、更高效的光生电子/空穴分离效率和VOCs降解性能。     

TiO2作用下土霉素的可见光敏化降解

研究了二氧化钛(TiO₂)存在时土霉素(OTC)在可见光下的降解。结果表明：单独可见光照下,OTC的光解效率随着pH的升高而逐渐增大。可见光和TiO₂的联合能显著促进OTC的降解,这主要归因于OTC的自光敏化作用。淬灭实验表明,在可见光/TiO₂体系中,超氧阴离子自由基(O₂^·-)和羟基自由基(·OH)能够氧化降解OTC,且O₂^·-是主要的活性物种。OTC初始浓度会影响其在可见光/TiO₂体系中的降解,过高或过低的OTC浓度都不利于其自身的去除;但是TiO₂用量的增加却能逐渐提高OTC的降解效率。     

光热脱盐-光催化降解复合膜的制备及其性能研究

以氯金酸(HAuCl₄)、氧化石墨烯(GO)和二氧化钛(TiO₂)为原料,通过一步水热法制备了具有光热催化活性的Au-GO/TiO₂纳米复合材料,以聚甲基丙烯酸甜菜碱(PSBMA)水凝胶包覆的Au-GO/TiO₂作为光热功能层,以聚氨酯(PU)静电纺丝纳米纤维膜作为支撑层,制备了具有光热脱盐和光催化降解双功能的复合膜。试验结果表明：该复合膜能够有效光催化降解水中的有机污染物,对金霉素、土霉素和地美环素的降解率分别达到49.26%、49.53%和51.58%;该复合膜能够以2.63 kg/(m²·h)的蒸发速率蒸发复合盐水。     

低电流密度下不同材质阳极电解生成过硫酸盐研究

以Si/BDD(Boron-doped diamond)、Ti/Sn O₂、Ti/Pb O₂、Ti/Pt 4种常见电极为阳极,考察其在电解Na₂SO₄生成过硫酸盐(PDS)过程中的电化学行为,以及低电流密度条件下电解质浓度,电流密度和PDS、H₂SO₄、NH₄SCN的投加对电解法制备PDS的影响。结果表明：在低电流密度条件下,生成PDS的主要途径是通过阳极电解水产生·OH来介导SO₄^2-的氧化;相同反应条件下,4种阳极中Si/BDD阳极电解体系对PDS的生成效果最佳,以Si/BDD电极为阳极,在Na₂SO₄浓度0.9 mol/L、电流密度60 m A/cm²条件下,电解60 min时生成的PDS浓度为24.12 mmol/L;提高电解质浓度和电流密度可以提高电流效率和PDS产量,向电解质中添加Na₂S     

CNTs负载TiO2对茜素红溶液的降解研究

以钛酸四丁酯为前驱体,冰醋酸为水解抑制剂,采用溶胶-凝胶法制备纳米TiO₂/CNTs复合催化剂。测定复合催化剂对不同浓度茜素红溶液的光降解活性,并对光催化降解动力学进行研究。结果表明,在CNTs负载质量分数7.5%、焙烧温度450 ℃和焙烧时间3.5 h条件下制备的TiO₂/CNTs复合催化剂光催化活性得到提升。相同条件下,TiO₂/CNTs对150 mg·L^-1茜素红溶液的最终降解率达67%,而TiO₂的最终降解率只有56%。复合催化剂光催化活性提升的原因是CNTs负载后光催化粒子在紫外光照射下生成更多的氢氧根活性自由基。光催化降解动力学符合Langmuir-Hinshelwood方程,催化剂对污染物的表观吸附是整个反应的“瓶颈”。随着反应浓度的增大,光催化降解反应的反应级数由一级反应逐渐下降为零级反应。     

用于喷墨印花染料纯化的自组装GO/TiO2复合纳滤膜的制备

数码喷墨打印技术对墨水高纯度和低含盐量要求,不断促使染料纯化技术的开发与研究。基于氧化石墨烯(GO)/纳米二氧化钛(TiO₂)自组装的纳滤膜材料的开发,探究了纳米TiO₂颗粒尺寸和与GO共混比例,所获最优GO/TiO₂复合纳滤膜中TiO₂颗粒尺寸为60 nm,与GO共混比例为1∶1。其纯水通量为10.69 L/(m²·h·bar),对NaCl和Na₂SO₄的截留分别为12.6%和15.7%,对铬黑T、刚果红和考马斯亮蓝R的截留均高于99%。采用自制的连续恒容渗滤装置对粗品墨水进行染料脱盐浓缩的实验,所获染料的浓度由最初的2.0 g/L浓缩至9.74 g/L,NaCl和Na₂SO₄浓度则由起始10 g/L分别下降至5.3 mg/L和11 mg/L,满足数码印花对墨水高纯度以及低盐度的要求。     

N-Zn/TiO2光催化氧化脱硫废液中亚硫酸钠的研究

采用溶胶凝胶法合成了氮、锌共掺杂二氧化钛催化剂（N-Zn/TiO₂）,用于催化氧化双碱法脱硫废液中的亚硫酸钠。通过X射线衍射、红外光谱、X射线光电子能谱和场发射环境扫描电镜对N-Zn/TiO₂催化剂的形貌和结构进行了表征。并考察了催化剂用量、溶液pH、空气流量、亚硫酸钠初始浓度对N-Zn/TiO₂光催化氧化亚硫酸钠的影响。实验结果表明：在不加N-Zn/TiO₂催化剂的情况下,将脱硫废液中的亚硫酸钠完全氧化需要8 h,而N-Zn/TiO₂在紫外光照射下能在1.5 h内将亚硫酸钠催化氧化完全。催化剂的用量对反应速率的影响最大,废液中亚硫酸钠的氧化速率随着催化剂用量的增多呈上升趋势。其次是溶液的pH对亚硫酸钠的氧化有较大影响,随着pH的增大,亚硫酸钠的氧化速率呈先增大后减小的趋势。实验所得到的最优反应条件为：催化剂用量为m（催化剂）/m（亚硫酸钠）=1/100,pH=6.5,空气流量为4 L/min。     

TiO2-incorporated polyelectrolyte composite membrane with transformable hydrophilicity/hydrophobicity for nanofiltration separation

The wettability of the membrane surface has shown obvious influent on the separation performance of the membrane. In this work, a hydrophilic PDA-[PDDA/TiO₂]⁺Cl^- membrane was prepared by a one-step codeposition of poly(diallyldimethylammonium chloride) (PDDA) polyelectrolyte solution containing positively charged TiO₂@ PDDA nanoparticles with the assistance of dopamine (DA). Such positively charged membrane can be transformed into a hydrophobic membrane PDA-[PDDA/TiO₂]⁺PFO^- via the counterion exchange between Cl^- and PFO^- (perfluorooctanoate). The transformation between hydrophilicity and hydrophobicity is reversible. For both hydrophilic and hydrophobic membranes, the nanofiltration performances were respectively investigated by the aqueous solution and ethanol solution of dyes including methyl blue (MB), Congo red (CR) and Evans blue (EB), and as well metal salt aqueous solution. The consecutive running stability and anti-fouling performance of both hydrophilic and hydrophobic membranes were explored. The results revealed that both membranes showed high nanofiltration performances for retention of dyes in (non)aqueous solution. For the hydrophilic membrane, the rejection of salts in a sequence is MgSO₄ > Na₂SO₄ > MgCl₂ > NaCl. Moreover, both     

新型纳米SO42-/TiO2催化剂制备及催化合成醋酸丁酯

采用高压水热法合成纳米锐钛矿相TiO₂前驱体,通过H₂SO₄溶液浸渍制备系列新型SO₄^2-/TiO₂催化剂,采用XRD、TG-DTG和TEM对其结构和形貌进行表征,并用于催化醋酸与正丁醇的酯化反应,考察H₂SO₄溶液浓度、浸渍时间和反应时间对酯化率的影响。结果表明,在H₂SO₄浓度1 mol·L^-1、浸渍时间12 h和反应时间180 min条件下,酯化率高达99.2%,催化剂具有优异的催化性能和较佳的重复使用性。     

硫酸钠/氧化硅复合定形相变材料的溶胶凝胶法制备和表征简

A sodium sulfate （NaeSO4）/silica （SiO2） composite was prepared as a shape-stabilized solid-liquid phase change material by a sol-gel procedure using Na2SiO3 as the silica source. Na2SO4 in the composite acts as a latent heat storage substance for solid-liquid phase change, while SiO2 acts as a support material to provide structural strength and prevent leakage of melted NazSO4. The microstructure and composition of the prepared composite were characterized by the N2 adsorption, transmission electron microscope （TEM）, scanning electron microscope （SEM）, Fourier transform infrared spectroscopy （FTIR） and X-ray diffraction. The results show that the prepared Na2SOJSiO2 composite is a nanostructured hybrid of NazSO4 and SiO2 without new substances produced during the phase change. The macroscopic shape of the NazSO4/SiO2 composite after the melting and freezing cycles does not change and there is no leakage of Na2SO4. Determined by differential scanning calorimeter （DSC） analysis, the values of phase change latent heat of melting and freezing of the prepared NazSO4/SiO2 （50%, by mass） composite are 82.3 kJ.kg i and 83.7 kJ.kg-1, and temperatures of melting and freezing are 886.0 ℃ and 880.6 ℃, respectively. Furthermore, the Na2SOJSiO2 composite maintains good thermal energy storage and release ability even after 100 cycles of melting and freezing. The satisfactory thermal storage performance renders this composite a versatile tool for high-temperature thermal energy storage.     

燃煤锅炉烟气中Na2SO4生成的化学动力学研究

准东煤燃烧过程中Na₂SO₄的形成会造成锅炉受热面沾污、尾部SCR催化剂失活等问题。烟气中Na₂SO₄形成及转化规律的研究对于预测和控制燃煤烟气中Na₂SO₄的形成有重要意义。发展了烟气中Na/Cl/S/O/H化学动力学模型,研究了烟气中Na₂SO₄的生成过程及转化机理,考察了含氧量、温度、SO₂浓度、H₂O浓度等因素对Na₂SO₄生成的影响。动力学计算结果表明,模型预测结果与实验数据吻合较好,验证了模型的准确性。烟气中的高氧气含量有利于Na₂SO₄的生成。高温加快化学反应的同时,抑制了Na₂SO₄的生成。SO₂和H₂O的影响效果受温度影响较大。反应路径分析表明,Na₂SO₄的生成路径有两个：一是依赖于SO₂直接氧化（NaCl→NaSO₃Cl→NaHSO₄→Na₂SO₄）,二是依赖于SO₂间接氧化（NaCl→NaO₂→NaSO₄→NaHSO₄→Na₂SO₄）。敏感性分析结果表明,Na₂SO₄的生成主要对系统中生成或消耗自由基的反应更为敏感。     

AgBr/Zn3(OH)2V2O7·2H2O可见光催化降解亚甲基蓝溶液

采用水热和沉淀两步合成法制备AgBr/Zn₃(OH)₂V₂O₇·2H₂O催化剂,研究其在可见光下降解亚甲基蓝溶液的性能,并考察催化剂用量、亚甲基蓝溶液初始浓度、pH值以及盐浓度对光催化性能的影响,评价AgBr/Zn₃(OH)₂V₂O₇·2H₂O催化剂的重复使用性能。结果表明,在前驱液pH为10、120 ℃水热10 h、Ag与Br物质的量比为0.20条件下制备的复合催化剂在可见光下反应120 min后,1.0 g·L^-1的催化剂对10 mg·L^-1的亚甲基蓝溶液脱色率达到85.2%。NaCl对亚甲基蓝的降解起抑制作用,Na₂SO₄对亚甲基蓝的降解起促进作用。催化剂重复使用4次后,光照120 min后的亚甲基蓝溶液脱色率可达66.4%。催化剂对不同初始浓度亚甲基蓝溶液的光催化降解符合一级动力学模型。     

Photocatalytic activity of TiO2/ZSM-5 composites in the presence of SO4 ion

TiO₂/ZSM-5 composites were prepared from SiO₂ of rice husk ash and TiO₂ sol from hydrolyzed TiOSO₄ salt. The combined effect of these two materials greatly enhanced the photocatalytic decolorization of methylene blue dye solution. The instant decolorization of the dye solution in the dark by the composite, TiO₂/ZSM-5 (wt ratio 1:1), resulted from the combination of the adsorption by ZSM-5 zeolite and TiO₂ nano-particles, and of Na₂SO₄ salt adhering to the composite surface. As a strong flocculating agent, the SO₄²⁻ ion caused the precipitation of the dye onto the composite surface which consequently enhanced the photocatalytic decolorization of the dye under UV irradiation. The composite, TiO₂/ZSM-5 (wt ratio 1:5), completely decolorized the methylene blue dye in 2.5 h, giving an equivalent performance to that of TiO₂, P-25 powder.     

Fabrication of anti-fouling polyamide nanofiltration membrane by incorporating streptomycin as a novel co-monomer

Polyamide (PA) thin-film composite (TFC) nanofiltration (NF) membrane has extremely broad application prospects in separation of monovalent/divalent inorganic salts mixed solution. However, membrane fouling is the main obstacle to the application of PA, TFC and NF membrane. Streptomycin (SM) is a hydrophilic antibiotic containing a large number of hydroxyl and amino groups. In this work, the NF membrane was prepared via interfacial polymerization (IP) between trimesoyl chloride (TMC) in the organicphaseand SM/piperazine (PIP) mixture in theaqueousphase. The NF membrane structure and performance were characterized in detail. The results showed that SM successfully participated in the IP. The negative charge and hydrophilicity of membrane surface were improved. The prepared membrane exhibited good anti-adhesion and anti-bacterial performance. Additionally, when the SM concentration was 2%, the prepared membrane exhibited the optimal permselectivity. The water permeance was 89.4 L·m^-2·h^-1·MPa^-1. The rejection of NaCl and Na₂SO₄ were 17.17% and 97.84%, respectively. The NaCl/Na₂SO₄ separation factor of the SM2-PIP/TMC membrane in 1000 mg·L^-1 NaCl and 1000 mg·L^-1 Na₂SO₄ mixed solution was 40, which was 3.3 times that of PIP/TMC membrane. It indicated that SM2-PIP/TMC demonstrated excellent monovalent/divalent salts separation performance. This work provided an easy and effective approach to preparing anti-fouling NF membrane while possessing superior monovalent/divalent salts separation performance.     

Preparation and characterization of sulfated TiO2 with rhodium modification used in esterification reaction and decomposition of methyl orange☆

A unique Rh/TiO_2 solid acid catalyst modified with H_2SO_4 was synthesized and evaluated in the esterification reaction of propylene glycol methyl ether and decomposition of methyl orange(MO) in aqueous phase under halogen lamp irradiation. For this purpose, rhodium(Rh) nanoparticles were loaded on SO_4~(2-)/TiO_2 via the photo-deposition method. It was found that SO_4~(2-)/Rh–TiO_2 exhibited stronger catalytic activity than SO_4~(2-)/TiO_2. The new catalysts were characterized by X-ray powder diffraction(XRD), Brunauer–Emmett–Teller(BET), Transmission electron microscopy(TEM) and high-resolution(HRTEM), X-ray photoelectron spectroscopy(XPS) and Fourier Transform infrared spectroscopy(FTIR). Results from XRD and BET show that SO_4~(2-)/Rh–TiO_2 has higher specific surface area and smaller pore size than SO42-/TiO_2. The distribution of loaded Rh was found to be uniform with a particle size of 2–4 nm. Data from XPS reveal that Rh primarily exists as Rh~0 and Rh~(3+)in Rh–TiO_2 and SO_4~(2)-/Rh–TiO_2. These valence forms of Rh likely contribute to the enhanced catalytic activity. Furthermore, FT-IR spectra of the catalysts show an abundance of surface hydroxyl groups, which help the formation of hydroxyl radicals and the enhancement of surface acid density. The results show that more acid sites are formed on the sulfated Rh–TiO_2, and these acidic sites are largely responsible for improving the catalytic performance. This superior SO_4~(2-)/Rh–TiO_2 catalyst has potential applications in reactions requiring efficient acid catalysts, including esterification reactions and waste water treatment.