Photodegradation of Oryzalin in aqueous isopropanol and acetonitrile

The phototransformation of Oryzalin was studied under UV light (λ_max ≥ 290 nm) and sunlight (λ_max ≥ 250 nm) in aqueous isopropanol and acetonitrile solution in absence and presence of TiO₂ as sensitizer. The rate of photodegradation of Oryzalin in different solvent system followed first-order kinetics, and calculated half-lives were found to be in the range of 23.52-53.75 h for UV light and 41.23-61.43 h for sunlight. From this study, total 12 photoproducts were identified and characterized on the basis of column chromatography and Q-Tof micromass spectral data. The plausible mechanism of phototransformation involved was hydrolysis, breaking of sulfonic bond, and loss of amino and sulfonic acid group.     

Visible leaf injury in young trees of Fagus sylvatica L. and Quercus robur L. in relation to ozone uptake and ozone exposure. An Open-Top Chambers experiment in South Alpine environmental conditions

An Open-Top Chambers experiment on Fagus sylvatica and Quercus robur seedlings was conducted in order to compare the performance of an exposure-based (AOT40) and a flux-based approaches in predicting the appearance of ozone visible injuries on leaves. Three different ozone treatments (charcoal-filtered; non-filtered; and open plots) and two soil moisture treatments (watered and non-watered plots) were performed. A Jarvisian stomatal conductance model was drawn up and parameterised for both species and typical South Alpine environmental conditions, thus allowing the calculation of ozone stomatal fluxes for every treatment. A critical ozone flux level for the onset of leaf visible injury in beech was clearly identified between 32.6 and 33.6 mmolO3 m(-2). In contrast, it was not possible to identify an exposure critical level using the AOT40 index. Water stress delayed the onset of the leaf visible injuries, but the flux-based approach was able to take it into account accurately.     

石墨相氮化碳协同UV-H_2O_2光催化降解亚甲基蓝

以三聚氰胺为前驱体,经热解—回流法制备了石墨相氮化碳(g-C3N4),采用XRD、FTIR、SEM、EDS、PL等技术对g-C_3N_4进行了表征。研究了g-C_3N_4在UV-H_2O_2体系中对废水中亚甲基蓝(MB)的光降解效果。实验结果表明,UV+g-C_3N_4催化剂+H_2O_2体系能协同降解MB,在初始MB质量浓度为20 mg/L、初始废水p H为5、废水体积为250 mL、g-C_3N_4加入量为0.10 g、H_2O_2浓度为0.4 mmol/L、反应温度为25℃的优化工艺条件下,紫外光照射70 min时MB脱色率达98.32%。g-C_3N_4催化剂具有较好的重复使用性能,使用5次后MB脱色率仍保持在95.10%。     

γ-射线辐照降解水中阿莫西林

研究了60Coγ-射线辐照条件下水中阿莫西林(AMX)的辐照降解,考察了AMX初始浓度、辐照剂量、p H、H2O2、自由基消除剂(碳酸氢钠和正丁醇)以及溶解氧等因素对AMX辐照降解的影响。结果表明,γ辐照可有效降解水中AMX,当AMX初始浓度为10.0 mg/L,辐照剂量为15 k Gy时,降解率达100%,随着AMX浓度增大,其降解率降低。碱性条件有利于AMX的降解,当p H为11,且辐照剂量大于10 k Gy时,AMX的降解率在90%以上。同时,加入H2O2可以促进AMX的降解;·OH自由基消除剂的存在和缺氧条件会明显抑制γ-射线对AMX的辐照降解,分析表明,AMX的降解主要是基于·OH自由基的氧化。     

超声辐射浸渍法制备Fe-Ni-Mn/Al_2O_3催化剂及性能研究

以Al2O3为载体,分别采用超声辐射浸渍法和普通浸渍方法制备Fe-Ni-Mn/Al2O3催化剂。采用BET、XRD和SEM对催化剂的理化性质和孔结构进行了分析,以模拟酸性绿B废水为研究对象考察催化剂的催化性能。实验结果表明,浸渍溶液pH值和焙烧温度显著影响催化剂的性能。与普通浸渍法相比,超声浸渍法制备的Fe-Ni-Mn/Al2O3催化剂对酸性绿B脱色反应表现出较高的催化活性。     

氮掺杂TiO2可见光光催化剂的制备及性能

以尿素和钛酸丁酯为原料,通过溶胶-凝胶法低温下制备了高可见光催化活性的氮掺杂TiO2(NDT)光催化剂,采用XRD、TEM、BET和UV-Vis DRS等测试手段对其进行了表征,并在自制光催化反应器中降解甲基橙评价了样品的光催化活性。结果表明,当氮与钛的摩尔比为0.5∶1时,350℃焙烧的样品(NDT350)具有最佳的可见光光谱吸收和光催化活性,该催化剂为锐钛矿晶相,平均粒径为21 nm,比表面积为89.13 m2/g。可见光辐照下,NDT350降解甲基橙的表观反应速率常数为1.381×10-2min-1,是商业P25催化剂的16.85倍。NDT350优良的可见光催化活性与其大的比表面积和强烈的可见光光谱吸收有关。     

清浊分流条件下的混凝-臭氧处理棉针织印染清废水

根据污染源头控制和废水回用的要求,对典型棉针织染整厂的不同生产过程废水排水水质特征进行了统计分析,提出了较实用的废水源头清浊分流方案。在此基础上重点研究了混凝-臭氧组合工艺对清废水处理效果,确定了最优的工艺条件。结果表明,清废水主要为洗水,占废水总量的25%～30%;混凝-臭氧组合工艺的最优工艺条件为：pH为6～9,PAC投加量为48 mg/L,PAM投加量为1.0 mg/L,臭氧接触时间为12 min（臭氧浓度为14.5 mg/L）,这时,清废水COD、色度去除率分别为71%和98%,实践证明,出水水质完全能够满足染整生产。     

Fe^3＋掺杂TiO2/凹凸棒复合材料的光催化性能

采用酸催化的溶胶-凝胶法制备了一系列Fe^3＋掺杂TiO2/凹凸棒（Fe^3＋-TiO2/ATP）复合光催化剂材料。在可见光条件下,以亚甲基蓝（MB）溶液的光催化降解反应,评价了样品的光催化性能,研究了TiO2负载量、Fe^3＋掺杂量和焙烧温度对复合材料光催化性能的影响。在单因素实验的基础上,采用正交实验设计（L25（53））优化了催化剂的制备条件。光催化实验结果表明,MB在复合材料上的光催化降解反应遵循Langmuir-Hinshelwood（L-H）动力学模型。正交实验结果表明,当TiO2负载量为15%、Fe^3＋掺杂量为0.5%和焙烧温度为550℃时,得到的复合材料对MB的光催化降解效率最佳,测得表观反应速率常数kapp为6.09×10^-3min^-1,反应4 h后MB的降解率（Dt）可达75.88%,相同实验条件下与P25（1.51×10^-3min^-1）相比较,反应速率提高了4.03倍,降解率提高了45.05%。另外,复合材料的沉降性能优于P25,易于分离,是一类有应用前景的复合光催化剂。敏世雄王芳魏立强王永生冯雷佟永纯韩玉琦     

紫外辐照-催化湿式过氧化氢氧化技术处理酸性大红GR染料废水

采用自制的负载型CuO-ZnO-CeO2/γ-Al2O3催化剂,常温常压下通过紫外辐照-催化湿式氧化技术处理酸性大红GR模拟染料废水。考察了催化剂加入量、H2O2加入量、废水pH、反应时间、初始酸性大红GR质量浓度等对废水脱色率的影响。实验得到最佳工艺条件为初始酸性大红GR质量浓度200mg/L,催化剂加入量10.0g/L,H2O2加入量2.0mL/L,废水pH4,反应时间2h。最佳工艺条件下废水脱色率达99.33%。