Phototransformation of fibrate drugs in aqueous media

The photochemical conversion of bezafibrate, gemfibrozil, fenofibrate and fenofibric acid has been examined in aqueous media. Irradiation with a solar simulator in distilled water caused about 10% degradation for the first three drugs after 200 hr, while fenofibric acid was completely degraded after 100 hr. Experiments have also been performed in the presence of nitrates or humic acids, considered as environmental photosensitizers, and only for gemfibrozil a reduction of degradation has been observed. Photoproducts have been characterized and the mechanistic pathways discussed on the basis of experimental and literature data.     

Photolytic decomposition of uc‐54229, a Proinsecticide of the Carbamate group

Phototransformation of UC‐54229 (1) [2,3‐dihydro‐2,2‐dimethyl‐7‐benzofuranyl‐N‐(trimethylamino acetyl)‐N‐methyl carbamate chloride] was studied under UV and visible light conditions. Photoirradiation of 1 with UV‐light resulted in the formation of five degradation products which on the basis of their mass and ¹H Nmr spectral analysis were characterised as 2, 3, 4, 5 and 6. It was observed that under the influence of light, UC‐54229 was degraded to acetyl‐carbofuran which under similar conditions underwent further transformation to the actual toxicant carbofuran. The degradation products or impurities present in 100% water soluble powder formulation were identified as carbofuran phenol and triethylamine hydrochloride.     

苯胺在含富里酸/Fe（Ⅲ）高盐水体中的光氯化

本文以典型芳香胺类有机物苯胺为模型化合物,研究苯胺在模拟太阳光照射下的光转化情况.考察高盐水体中,不同浓度富里酸、Fe（Ⅲ）及不同pH条件下,苯胺氯代产物光化学生成的情况,并通过苯胺在实际海水中的光反应,证明苯胺在天然海水中经太阳光照,可以生成其氯代产物.富里酸与铁离子形成络合物,有利于苯胺氯代反应的发生,反应过程中,4-氯苯胺的生成量要高于2-氯苯胺.在FA/Fe（Ⅲ）/Cl-共存水环境中,富里酸浓度相对于铁离子浓度对苯胺氯代反应影响小,活性铁物种在该反应中占据相对更重要的地位.     

水中氟喹诺酮类抗生素光降解过程中抑菌活性的变化

本文采用体外抑菌实验,以大肠杆菌（Escherichia coli）为受试菌种,比较研究了模拟日光（λ>290 nm）照射下,恩诺沙星、环丙沙星、二氟沙星、沙拉沙星等4种不同氟喹诺酮类抗生素（FQs）在纯水、淡水、海水中光降解过程抑菌活性的变化及作用机制. 发现恩诺沙星和二氟沙星在光解初始阶段（0—t1/2）,光解溶液的抑菌活性没有出现显著降低的趋势（P>0.05）,这是因为其光转化分别生成了抑菌活性更大的产物环丙沙星和沙拉沙星,且这两种产物在0—t1/2不断积累. 区别于前两种FQs,环丙沙星和沙拉沙星光降解过程中抑菌活性呈明显降低趋势（P<0.01）,表明其产物的抑菌活性相对于母体化合物可以忽略. 纯水、淡水和海水中同种FQ光解过程中表现出相似的抑菌活性变化规律.     

溶解性有机质引发2,3-二溴丙基-2,4,6-三溴苯基醚光转化机理

光转化是水体中有机污染物的重要转化途径,决定污染物的环境暴露和风险。激发三线态溶解性有机质(³DOM^*)能够引发酚类、胺类和共轭二烯类污染物的间接光降解,反应机理涉及电子转移、质子转移和能量转移。然而,³DOM^*与新型溴代阻燃剂(NBFRs)及具有类似结构的污染物的反应机理尚不清楚。本研究选取2,3-二溴丙基-2,4,6-三溴苯基醚(DPTE)为NBFRs模型化合物,以苯乙酮模拟DOM,通过光化学实验和密度泛函理论(DFT)计算,探究³DOM^*与NBFRs的反应活性、反应位点和反应途径。结果表明,激发三线态苯乙酮(³AP^*)对DPTE表观光降解的贡献为41.7% ± 2.2%,二者的二级反应速率常数为(1.49 ± 0.24) × 10⁸ L·mol⁻¹·s⁻¹。DPTE的子结构模型化合物与苯乙酮的光化学实验表明,³AP^*与DPTE的反应位点为DPTE苯基上的溴。DFT计算表明,³AP^*通过向激发态DPTE转移电子使DPTE生成脱溴中间体,脱溴中间体与基态苯乙酮发生质子转移反应生成脱溴产物。所揭示的³AP^*引发 DPTE 光转化机理,有助于评价和预测水体中其他有溴代苯基醚结构的污染物光转化产物和动力学。     

Photocatalytic treatment of dimethoate by solar photocatalysis at pilot plant scale

Titanium dioxide photocatalysis, using 200 mgl⁻¹ of TiO₂, and photo-Fenton, using 20 mg l⁻¹ of iron, were applied to the treatment of dimethoate dissolved in water at 50 mg l⁻¹. A heterogeneous photocatalysis test was performed in a 35-l solar pilot plant with Compound Parabolic Collectors (CPCs) under natural illumination. A homogeneous photocatalysis test was performed in a different solar pilot plant with four CPC units and a total volume of 75 l. In this work total disappearance of dimethoate and 90% of mineralization were attained in both solar treatments. Treatment time, hydrogen peroxide consumption and ferric phosphate precipitation during photo-Fenton treatment were discussed. An erratum to this article can be found at     

C60在模拟气溶胶中的光降解实验与理论计算

燃烧及碳纳米材料的生产和处置过程中,均有可能产生富勒烯（C60）等纳米颗粒物.这些纳米颗粒物进入大气后,主要存在于气溶胶中.由于本身的共轭结构C60可以吸收紫外可见光发生光氧化转化,研究C60在气溶胶中的光转化对于评价其环境归趋具有重要意义.本研究以环己烷、甲苯和二氯甲烷等溶剂模拟气溶胶表面液体层,采用模拟日光实验和密度泛函理论（DFT）计算研究了C60在3种溶剂中的光化学转化.实验结果表明,C60在环己烷、甲苯和二氯甲烷中的光降解符合准一级动力学,光解速率常数分别为（0.80±0.01）×10-3、（3.80±0.02）×10-3、（14.80±0.20）×10-3 min-1.DFT计算结果表明,C60在3种溶剂中均可以通过光致产生1O2发生氧化反应.然而,仅在二氯甲烷中C60可以通过电子转移生成O2·-来促进C60的光转化.甲苯溶剂中激发态甲苯分子可以敏化C60产生C60·-从而加快C60的降解.理论计算结果有助于解释实验中C60在二氯甲烷中光解速率最快,在甲苯中光解速率比在环己烷中快的现象.     

空气污染对城市太阳辐射影响的试验研究

对太阳辐射强度和空气污染浓度的观测分析表明:晴日太阳辐射的减弱与空气污染浓度密切相关。因此可以用太阳辐射强度的长期变化间接推断当地大气质量的长期变化。     

有机物对紫外光照下亚硝氮生成的影响

通过静态间歇试验,对紫外光照下水中无机氮的转化进行了研究,重点考察了有机物在反应过程中对亚硝氮生成的促进作用,分类比较了不同有机物的作用效果.结果表明:在紫外光照下,氨氮不能转化为亚硝氮,硝氮可以转化为亚硝氮;有机物的投加可以促进亚硝氮的生成;不同有机物对亚硝氮形成的促进作用大小与有机物的还原性有关,还原性愈强,促进作用愈大;有机物促进作用大小的顺序如下:相同碳链醇醛酸酮、官能团愈多促进作用愈大,相同官能团碳链愈长促进作用愈大.     

双氯芬酸钠水溶液的辐照降解

利用60Co γ射线辐照双氯芬酸钠水溶液,探讨了不同辐照剂量下初始浓度、自由基促进剂和淬灭剂、水体共存物质等因素对降解的影响,研究其降解途径,并和等离子体放电降解效果进行了对比.结果表明,γ辐照可有效降解双氯芬酸钠,但矿化过程要长于降解过程,当初始浓度为20.5,30.4和50.1 mg·L-1时, 反应动力学常数分别为2.55,2.12和1.90 kGy-1,呈现下降趋势,自由基促进剂和淬灭剂的影响结果说明该降解反应主要通过羟基自由基(·OH)、水合电子(e-aq)和氢原子(H·)等活性基团与目标分子反应实现,水体中常见的共存物质如硝酸根和腐殖酸对降解不会造成影响,降解途径主要是通过·OH的氧化作用和e-aq与H·的还原作用实现的.     

微波辐射技术在聚乙烯醇降解反应中的应用

考察了微波功率、pH值、H2O2用量和反应时间对聚乙烯醇降解反应的影响.实验表明,在微波辐射条件下,微波功率为800W,辐射时间为1min,pH值为3,H2O2用量为依22gH2O2·100g-1PVA时,5ml聚乙烯醇(7%)的平均聚合度能够在1min内降至67.与常规油浴加热相比,反应速度提高10—20倍.     

Y-射线辐照催化降解水溶液中萘普生

利用^60co产生的y-射线辐照水溶液中萘普生,研究了萘普生的降解特性．通过测定辐射后萘普生的浓度,探讨了吸收剂量、溶液pH、不同添加物（H2O2,CO23-;t-BuOH）对萘普生降解效果的影响．结果表明,1一射线辐照能有效催化降解水溶液中的萘普生,降解过程符合准一级动力学方程．萘普生浓度为23．6mg·L^-1,吸...     

光照法处理垃圾渗滤液试验研究

采用直接光照处理青山垃圾填埋场和流芳垃圾填埋场的渗滤液,结果表明,直接光照处理4h,COD去除率分别为31%和18%,其主要原因在于青山垃圾填埋场中含有较多Fe和Cu等光催化物质及自身的光降解.直接光照对NH3-N和总-N的处理效果不佳.     

Are policy incentives for solar power effective? Evidence from residential installations in the Northeast

State incentives for solar power have grown significantly in the past several years. This paper examines the effectiveness of policy incentives to increase residential solar photovoltaic (PV) capacity. We use county-level panel data and control for demographic characteristics, solar resources, and pro-environmental preferences. Results show that among financial incentives, rebates have the most impact with an additional $1 per watt rebate increasing annual PV capacity additions by close to 50%. Factors that affect financial returns to solar PV such as electricity price and solar insolation are also found to be significant. Results also point to a significant positive relationship between hybrid vehicle sales and residential PV capacity growth, indicating the importance of pro-environmental preferences as a predictor of solar PV demand. Back of the envelope calculations suggest that the cost of carbon mitigation through rebates is around $184 per ton of CO₂.     

不同电子束能量和剂量辐照降解恩诺沙星有机污染物

应用3、5、10 MeV电子束能量和0.6、1.06、1.92、2.62、3.33、4.09、5.1、9.4、13.84、21.68 kGy共10个不同辐照剂量下,对恩诺沙星化合物的辐照降解研究,分析不同电子束能量和辐照剂量对化合物降解率的影响.结果表明,电子束能量对少量恩诺沙星样品的降解率基本没有影响;当辐照剂量为1.06 kGy时,恩诺沙星降解率已达93%;10 MeV的电子束能处理含恩诺沙星水样的最佳厚度为120 mm,辐照降解率不低于94%.由此可见,电子束辐照是有效降解恩诺沙星难降解化合物的技术方法,并适合大规模推广应用.     

生石灰与微波协同作用对污泥脱水的影响

采用生石灰与微波协同作用,对广州市猎德污水厂浓缩污泥脱水的影响进行了实验研究.结果表明,单独投加生石灰,加入量为40 g·L-1时,污泥比阻由原来的4.72×1013 m·kg-1降至1.9×1012 m·kg-1,降低了约96%;单独使用微波调理污泥,在800W功率微波下辐射100s,可使污泥比阻由原来的4.72×1013 m·kg-1降至1.28×1013 m·kg-1,降低了约72.9%;将经投加4g生石灰调理的100mL污泥在功率800W的微波下辐射100s,污泥比阻进一步降低至0.98×1011 m·kg-1,降低了约99.8%,比单独投加生石灰提高了约3.8%,提高了污泥的脱水性能.与微波协同作用可以强化污泥脱水,并在提高污泥脱水性能的同时减少了生石灰的用量.     

Effect of acute whole-body proton irradiation on hematological and intestinal variables in mice

Female C57BL/6 mice were exposed to a single dose of protons or ⁶⁰Co gamma rays at 20 mGy and 2 Gy, which represent the recommended limit for annual occupational exposure and the daily fractional dose for patients undergoing radiotherapy, respectively. A control group was not exposed to radiation. The number of peripheral blood, bone marrow, and spleen cells was assessed 24 h after radiation to investigate the marrow suppression. The number of lymphocytes and neutrophils in peripheral blood was significantly lower in mice exposed to the higher dose of radiation than in the nonirradiated mice. However, at a low dose of radiation, there were no discernable hematological effects. The frequency of micronuclei in bone marrow cells was increased only after the high dose of gamma radiation. Radiation-induced intestinal apoptosis was measured using terminal deoxynucleotide transferase labeling assay. The magnitude of damage was greater after gamma irradiation than after proton irradiation at the same dose. Among the systemic biological end point to predict whole body radiation effect, the apoptosis of intestinal crypts may be the most sensitive parameter to provide information even at low dose of radiation.     

偶氮类染料刚果红水溶液的辐射降解

利用60Coγ射线、电子束辐照刚果红水溶液,研究其降解行为.考察了刚果红水溶液辐照前后紫外可见光谱的变化、刚果红的降解率及溶液总有机碳(TOC)的去除率.通过不同气氛饱和辐照,对比了各种活性粒子对降解效果的影响.初步研究了初始pH值、H2O2和TiO2的加入对刚果红水溶液降解效果的影响.结果表明,60Coγ射线、电子束辐照是一种有效的去除水体中刚果红染料的方法,其降解效果在不同体系中均可以达到100%.高剂量下TOC去除率可以达到85.7%.H2O2和TiO2的加入可以有效提高刚果红的降解效率.