Multifunctional Zn0.3Al0.4O4.5 crystals: An efficient photocatalyst for formaldehyde degradation and EBT adsorption

The Zn_0.3Al_0.4O_4.5 nanoparticles (ZnAlONPs) with size of 70–90 nm are used as an efficient photocatalyst for formaldehyde (HCHO) degradation and effective adsorbent for the removal of eriochrome black-T (EBT) dye from synthetic aqueous solution. Degradation of HCHO reactions were studied using TiO₂ (homemade), TiO₂ (P-25) and ZnAlONPs by irradiating under 18 W daylight lamp source for photocatalytic degradation. The HCHO degradation rate is about 67, 76 and 89% for TiO₂ (homemade), TiO₂ (P25) and ZnAlONPs during 2 h reaction, respectively at initial formaldehyde gas concentration of 20 ppm. Maximum adsorption capacity was optimized by changing the parameters such as pH, EBT concentration and adsorbent dosage. A  200 mg of ZnAlONPs are useable for quick removal of EBT (>95%). Langmuir isotherm model showed a maximum adsorption capacity of 90.90 mgg⁻¹. The ZnAlONPs could be successfully reused upto 5^th adsorption/desorption cycle for EBT dye removal from water samples.     

A twofold interpenetrating two‐dimensional zinc(II) coordination polymer: synthesis,crystal structure and physical properties

A novel twofold interpenetrating two‐dimensional (2D) Zn^II coordination framework, poly[[(μ‐1,3‐bis(2‐methyl‐1H‐imidazol‐1‐yl)benzene‐κ²N³:N³)(μ‐naphthalene‐2,6‐dicarboxylato‐κ²O²:O⁶)zinc(II)] dimethylformamide monosolvate], {[Zn(C₁₂H₆O₄)(C₁₄H₁₄N₄)]·C₃H₇NO}_n or {[Zn(1,3‐BMIB)(NDC)]·DMF}_n (I), where H₂NDC is naphthalene‐2,6‐dicarboxylic acid, 1,3‐BMIB is 1,3‐bis(2‐methyl‐1H‐imidazol‐1‐yl)benzene and DMF is dimethylformamide, was prepared and characterized through IR spectroscopy, elemental analysis, thermal analysis and single‐crystal X‐ray diffraction. Single‐crystal X‐ray diffraction analysis revealed that (I) exhibits an unusual twofold interpenetrating 2D network. In addition, it displays strong fluorescence emissions and a high photocatalytic activity for the degradation of Rhodamine B (RhB) under UV‐light irradiation.     

大气环境下的钢筋混凝土桥梁时变可靠度分析

为了探究钢筋混凝土桥梁抗力退化对桥梁可靠性能的影响,综合考虑一般大气环境下混凝土强度、钢筋强度、混凝土与钢筋黏结性能的降低,建立普通钢筋混凝土桥梁的抗力退化时变模型,分析规范车辆荷载作用的桥梁时变可靠度。研究结果表明,(1)一般大气环境下,桥梁抗力随着服役时间的增加而减小,其中钢筋强度退化对桥梁抗力的影响最大,其次是钢筋与混凝土黏结性能降低,而混凝土强度退化对桥梁抗力的影响相对较小; (2)桥梁可靠指标随着服役时间的增加而减小,密集行车占比越大,桥梁承载能力失效的概率就越大;非平稳车载作用下的桥梁可靠指标小于平稳车载,桥梁需要维修补强的时间比平稳车载提前; (3)多梁式简支梁桥在建造时应该提高边梁的安全储备,在管养时可以采取限载措施进行干预。     

Stability and Removal of Benzophenone-Type UV Filters from Water Matrices by Advanced Oxidation Processes

Benzophenone (BP) type UV filters are common environmental contaminants that are posing a growing health concern due to their increasing presence in water. Different studies have evidenced the presence of benzophenones (BP, BP-1, BP-2, BP-3, BP-4, BP-9, HPB) in several environmental matrices, indicating that conventional technologies of water treatment are not able to remove them. It has also been reported that these compounds could be associated with endocrine-disrupting activities, genotoxicity, and reproductive toxicity. This review focuses on the degradation kinetics and mechanisms of benzophenone-type UV filters and their degradation products (DPs) under UV and solar irradiation and in UV-based advanced oxidation processes (AOPs) such as UV/H₂O₂, UV/persulfate, and the Fenton process. The effects of various operating parameters, such as UV irradiation including initial concentrations of H₂O₂, persulfate, and Fe²⁺, on the degradation of tested benzophenones from aqueous matrices, and conditions that allow higher degradation rates to be achieved are presented. Application of nanoparticles such as TiO₂, PbO/TiO₂, and Sb₂O₃/TiO₂ for the photocatalytic degradation of benzophenone-type UV filters was included in this review.     

185 nm UV降解水中4-CP、4-NP和Rh B的研究

本文以对氯苯酚(4-CP)、对硝基苯酚(4-NP)和罗丹明B(Rh B)为模型有机物(以4-CP和4-NP为小分子模型有机物,以Rh B为大分子模型有机物),分别研究了185 nm UV对水中这3种模型有机物的降解规律、性能和效果.研究结果表明,185 nm UV直接对水中4-CP、4-NP和Rh B有很好的降解效果.研究内容包括:185 nm UV降解模型有机物的浓度、TOC(Total organic carbon)浓度、185 nm UV降解模型有机物过程中溶液pH及电导率变化、以及降解模型有机物过程中产生的无机离子等几个方面.     

TiO2/斜发沸石光催化降解罗丹明B的研究

制备了一系列TiO₂/斜发沸石催化剂(不同焙烧温度、不同粒度和不同负载量),它们在紫外光照射下可降解有机染料罗丹明B(RhB).发现焙烧温度为500℃、粒度为180—200目、TiO₂实际质量分数为6.18%的催化剂样品活性较好.将其与P25对比,发现其降解速率虽低于P25(紫外光照84 min,P25COD变化率为100%,而焙烧温度为500℃的TiO₂/斜发沸石催化剂经紫外光照5.5 h,COD变化率为71.8%),但是TiO₂/沸石催化剂易于回收再利用,而纯P25因为颗粒细小,沉降速率慢,而不能快速分离.用XRD、TEM、BET、TG-DTA和紫外可见漫反射等方法表征了这些催化剂,结果表明催化剂比表面积增大有利于催化活性的提高.     

H2O2络合凝胶法制备纳米TiO2/SiO2复合催化剂及其光催化性能

采用H2O2络合凝胶法获得钛的络合物[TiO(H2O2)]2 水溶胶,并与SiO2水溶胶包覆复合,制备了纳米TiO2/SiO2复合半导体催化剂,其结构经XRD和BET表征。以含阳离子艳红染料模拟废水降解为模型反应,考察了复合催化剂的光催化性能。实验结果表明:经650℃焙烧后的复合催化剂中TiO2粒径为9.8 nm,光催化活性最好,SiO2的最佳掺杂量为25%。     

维生素C溶液有氧降解动力学

建立了一种恒温高压氧药物稳定性加速试验方法, 用这种方法可在较短的时间内求得药物氧化反应的动力学参数. 以10%维生素C溶液为例, 维生素C在有氧和无氧条件下均可降解, 总的降解速率常数k_t由两部分构成: k_t＝k_an＋k_ae, k_an为无氧降解速率常数, 可表达为k_an＝A_an•exp(－E_a,an /RT); k_ae为有氧降解速率常数, 可表达为k_ae＝A_ae•exp(－E_a,ae/ RT)• .     

超声MnO2联用降解丁基罗丹明B染料

采用超声MnO2体系降解丁基罗丹明B染料,考察了pH值、声强、MnO2投加量等因素对染料降解过程的影响。实验结果表明,溶液pH=3.0,MnO2投加量为1.5g/L,声强=40.7W/cm2,超声辐照10mg/L的罗丹明B溶液48m in,染料的脱色率为98.73%;超声和MnO2的协同效应在酸性条件下较为明显,溶液中产生大量.OH强化了对染料的声化学脱色和降解过程;丁基罗丹明B的超声降解过程以自由基的氧化反应为主,服从动力学一级反应。     

聚乙撑二氧噻吩阳极降解的研究

研究了聚乙撑二氧噻吩(PEDOT)膜在水溶液中的阳极降解过程. 研究发现PEDOT的阳极过程可以分为p掺杂区[电位范围－0.3～0.5 V (相对于饱和甘汞电极; vs. SCE)]、过渡区[电位范围0.6～1 V (vs. SCE)]、过氧化区[电位范围1.2～1.6 V (vs. SCE)]三个电位区域. 用电化学阻抗谱法、循环伏安法、红外光谱技术、膜电阻测量以及电子自旋共振技术分别研究了PEDOT膜在这三个电位区域的行为. 结果表明: PEDOT膜在这三个电位区域的性质有明显不同. 在p掺杂区PEDOT膜的官能团、共轭结构、导电性均保持, 即在这个电位区发生可逆的掺杂/脱掺杂反应, 膜几乎不降解. 在过渡区和过氧化区, PEDOT膜均发生了降解. 与传统的导电聚合物在高电位的阳极降解的过氧化过程不同, 我们认为膜在较高电位(过渡区)发生一个驰豫过程, 该过程使得膜的官能团改变, 但是膜的共轭结构和导电性均保持; 而在更高的电位区(过氧化区)膜的降解和一般意义的过氧化降解相同, 此时膜的官能团、共轭结构、导电性均发生不可逆的破坏.