Determination of hydroxyl radicals in TiO2/Ti photoelectrocatalytic oxidation system using Fe（phen）3^2＋ spectrophotometry

A new method of determining the cumulate concentration of hydroxyl radicals in the TiO2/Ti photoelectrocatalytic（PEC） oxidation system was established by o-phenanthroline-Fe（Ⅱ）（Fe（phen）3^2＋） spectrophotometry and using anion exchange membrane. Fe （phen）3^2＋ can be oxidized to o-phenanthroline-Fe（Ⅲ）（Fe（phen）3^3＋） by strong oxidization of hydroxyl radicals（·OH）. Then the cumulate concentration of hydroxyl radicals can be calculated through determining the change of the Fe（phen）3^3＋ absorbency at 509 nm. In addition, the research results showed the production rate of hydroxyl radicals was affected obviously by pH of solution, the cumulate concentration of hydroxyl radicals was the largest at nearby the initial pH 6.3 （isoelectric point）, and the change direction of pH after illumination tended to nearby isoelectric point.

Regulation of Superoxide Anion Radical During the Oxygen Delignification Process

In this study, the superoxide anion radicals were generated by the auto-oxidation of 1,2,3-trihydroxybenzene and determined by UV spectrophotometry, and the reaction was found to be facilitated by anthraquinone-2-sulfonic acid sodium salt. The bamboo kraft pulps were treated by the 1,2,3-trihydroxybenzene auto-oxidation method or the 1,2,3-trihydroxybenzene auto-oxidation combined with anthraquinone-2-sulfonic acid sodium salt to show the ef-fect of the superoxide anion radicals during the oxygen delignification of bamboo kraft pulp and the enhancing af-fect of anthraquinone compounds as an additive on delignification. The results indicated that the superoxide anion radicals could react with lignin and remove it from pulp with negligible damage on cellulose, and the an-thraquinone-2-sulfonic acid sodium salt could facilitate the generation of superoxide anion radical to enhance delig-nification of pulps. The oxygen delignification selectivity could be improved using the 1,2,3-trihydroxybenzene auto-oxidation system combined with anthraquinone-2-sulfonic acid sodium salt.

Efficient and selective photocatalytic nitrite reduction to N_(2)through CO_(2)anion radical by eco-friendly tartaric acid activation

In this study,the environmentally friendly precursor,tartaric acid(TA),was employed for the generation of CO_(2)anion radical(CO_(2)^(·-))in an advanced UV/TA/Fe^(3+)system to reduce the hazardous NO_(2)^(-)-N in wastewater.To optimize this process,various factors,including the dosage of Fe^(3+),TA,and p H,were systematically investigated for their impact on the reduction process.Under the conditions of 3 mmol/L Fe^(3+)dosage,10 mmol/L TA dosage,and a pH of 2.5,NO_(2)^(-)-N was effectively removed from the water within 60 min,selectively transformed into N_(2),with a remarkable N_(2)selectivity of 91.2%.In the optimal conditions,the NO_(2)^(-)-N reduction mechanism in the UV/TA/Fe^(3+)system and the critical role of CO_(2)^(·-)were illustrated.Finally,this study explored the reduction of real nitrified seawater using the UV/TA/Fe^(3+)system.The results demonstrated that the UV/TA/Fe^(3+)system could completely eliminate NO_(2)^(-)-N and achieve a N_(2)selectivity of up to 90%,with minimal interference from coexisting ions.This work holds promising implications for the environmentally benign treatment of nitrite-polluted wastewater.

锗—132对氧自由基清除作用的研究

用ＦｅＳＯ４－ＮＡＤＰＨ引发大鼠肝微粒体产生羟自由基（ＯＨ），用黄嘌呤／黄嘌呤氧化酶（Ｘ／ＸＯ）系统产生超氧阴离子自由基（Ｏ２），分别用电子自旋共振技术（ＥＳＲ）和比色法研究了羧乙基锗倍半氧化物（锗—１３２）对ＯＨ和Ｏ２产生量的影响。结果表明分别向产生ＯＨ和Ｏ２的反应体系中加入锗—１３２后，可使ＯＨ和Ｏ２的产生量显著减少，且随加入锗—１３２剂量的增加，ＯＨ和Ｏ２的产生量减少也越显著。本研究结果说明锗—１３２对ＯＨ和Ｏ２具有直接清除作用。

功能化基团对C_(60)-β-丙氨酸衍生物清除超氧阴离子自由基O_2^-·能力的影响

Three water-soluble β-alanine C 60 adducts with different addition numbers, C 60(NHCH 2CH 2COONa) nH n(n=1,5,9), were synthesized. The products were characterized by FTIR, 1H NMR and elemental analysis. The antioxidant activity of these C 60 adducts as the quencher for superoxide anion radical O -· 2 was evaluated by chemiluminescence in the system of pyrogallol-luminol. The results indicate that the three C 60 derivatives are all excellent quencher for superoxide anion radical O -· 2. The concentrations of 50% inhibition are 252, 140, 112 μmol/L respectively. This high efficiency should be attributed to many factors such as the numbers of remaining double bonds, donor effect of amino group and steric effect. However, the above results also suggest the effect of the adducted β-alanine groups is predominated in this system.

天冬酰胺缩2,4-二羟基苯甲醛Schiff碱及其稀土配合物的合成与抗O_2^-·研究

合成了天冬酰胺缩 2 ,4 二羟基苯甲醛Schiff碱及其La、Nd、Er、Dy四种稀土配合物 ,用元素分析、红外光谱、紫外光谱、摩尔电导率等手段进行了结构分析。采用EPR技术对所合成Schiff碱及其配合物的抗超氧阴离子自由基 (O-2 ·)性能进行了探讨 ,结果表明 ,所合成的化合物具有显著的清除O-2 ·的功能 ,而配合物对O-2 ·的清除率高于Schiff碱配体。

甲基丙烯酸2,2,2-三氟乙酯的可控聚合

采用活性阴离子聚合、原子转移自由基聚合(ATRP)溶液聚合法,分别对甲基丙烯酸2,2,2-三氟乙酯(TFEMA)进行分子设计,合成了结构明确的PTFEMA。采用IR,NMR,DSC对聚合物的结构与性能进行了表征;采用GPC对聚合物的分子量及其分子量分布进行了考察。

扩散渗析法回收废铅膏电解液中硫酸的实验研究

工业废旧铅蓄电池电解产生的酸性废水中含有大量硫酸,对其中的硫酸进行回收利用。以工业废铅膏为原料进行固相电解,产生硫酸浓度约20 g/L的废酸。采用7171阴离子交换膜,通过扩散渗析法对废铅膏电解液中的硫酸进行回收,两段酸回收率约75.2%。根据废铅膏电解液杂质含量情况,选择钠离子对硫酸的回收进行实验分析,结果表明酸的浓度不同,钠离子的浓度变化不同;钠离子扩散渗析是一个独立的过程,与溶液的酸浓度无关,只与自身的浓度差有关;硫酸的扩散渗析过程与溶液的硫酸浓度有关。扩散渗析模拟实验验证了扩散渗析能有效的回收硫酸。

2-氯代苯甲醛丙氨酸席夫碱及其3d-过渡金属配合物的合成与表征

合成了 2 -氯代苯甲醛丙氨酸席夫碱及其与Cu(Ⅱ )、Ni(Ⅱ )、Co(Ⅱ )、Zn(Ⅱ )离子所形成的配合物 ;以元素分析、摩尔电导、热重、红外光谱、拉曼光谱、1 HNMR谱等手段研究了化合物的组成和配位环境 ;对所合成的化合物进行了抑制超氧自由基的初步实验 ,发现虽然 2 -CAZn、2 -CACo对DNA具有明显作用 ,但该系列化合物对超氧自由基的抑制能力较弱 .

W/O微乳液体系中SA和MS清除·O_2^-的研究

以水溶液体系作为对照,利用分光光度法研究了W/O型微乳液体系中水杨酸(SA)和水杨酸甲酯(MS)清除超氧阴离子自由基(.O2-)的性能.结果发现,在水浴时间为20 min、pH值为8.20和邻苯三酚加入量适宜的情况下,W/O微乳液体系中SA、MS对.O2-的清除率分别可达72.92%、81.47%.微小的pH值变化会引起邻苯三酚自氧化速率的显著变化,电解质溶液对其也有明显的影响,但对SA、MS清除.O2-的能力影响不大.

Active Oxygen Radical Scavenging Ability of Water-Soluble β-Alanine C_(60) Adducts

Water-soluble b-alanine C60 adducts were synthesized, and the scavenging ability to superoxygen anion radical O2- and hydroxyl radical.OH were studied by autoxidation of pyrogallol and chemiluminescence, respectively. It was found thatβ-alanine C60 adducts showed an excellent efficiency in eliminating superoxygen anion radical and hydroxyl radical. The 50% inhibition concentration (IC50) for superoxygen anion radical and hydroxyl radical were 0.15 mg/mL and 0.048 mg/mL, respectively. The difference should be mainly attributed to the different scavenging mechanisms.

离子色谱法测定墓葬壁画土壤中4种阴离子

对离子色谱法快速测定墓葬壁画土壤中4种阴离子(F^(-)、Cl^(-)、SO_(4)^(2-)、NO_(3)^(-))的测定方法进行了优化。采用L_(9)(3^(4))正交实验确定了样品预处理的最佳参数:准确称取1.000 g样品加入20 mL超纯水,在振荡温度20℃,振荡转速180 r/min条件下提取40 min。淋洗液为25 mmol/L的KOH溶液,分析柱为Ion Pac AS11-SH(250 mm×4.0 mm),净化后的滤液通过电导检测器测定。在此方法下,各离子的检出限为0.066~0.078 mg/L,相对标准偏差为0.77%~2.23%(n=7),回收率为95.9%~105.8%。

二氧化碳阴离子自由基在水处理中的应用

高级还原技术作为近年来新兴的水处理技术之一,主要通过外加能量激活常规的还原剂而产生强还原性自由基和水合电子,还原去除水中有机污染物、重金属离子、硝酸盐等毒性污染物.二氧化碳阴离子自由基(CO_(2)^(·-))作为一种还原性自由基,具有极强的还原性,能快速与水中多种污染物反应,在水处理中具有研究、开发和推广应用价值.结合国内外文献,介绍CO_(2)^(·-)的结构、理化性质和产生途径,以及其在去除水中有机氯、硝酸盐及重金属等污染物方面的应用,并详细论述影响降解效果的因素和降解机制.最后,对CO_(2)^(·-)的未来研究方向和应用前景进行展望.

Cu(Ⅱ)/Na_(2)SO_(3)体系降解磺胺甲恶唑的效能及机理

利用Cu(Ⅱ)催化Na_(2)SO_(3)降解磺胺甲恶唑(SMZ),并探究降解效能及机理。结果表明,Cu(Ⅱ)/Na_(2)SO_(3)体系降解SMZ的最佳反应条件如下:pH为7、SMZ初始浓度为0.3 mg/L、Cu^(2+)浓度为0.10 mmol/L、Na_(2)SO_(3)浓度为0.50 mmol/L、温度为25℃,反应60 min后SMZ降解率达到61.3%。电子顺磁共振波谱结果和醇抑制剂实验结果证明,Cu(Ⅱ)/Na_(2)SO_(3)体系降解SMZ的主要活性物质是·OH和SO_(4)^(·-),其贡献率分别为31.6%和64.8%。虽然水体背景成分氯离子(Cl^(-))和碳酸氢根离子(HCO3-)对SMZ的降解起到一定抑制作用,但是Cu(Ⅱ)/Na_(2)SO_(3)体系对实际水体中SMZ仍有较好的降解效能。

桑色素铁配合物消除超氧基阴离子自由基的理论研究

采用量子化学的密度泛函(DFT)法,用Gaussian 09程序包优化了桑色素(Morin)与Fe^(2+)三种可能的配合物及其与超氧基阴离子自由基(O·―2)相互作用后的几何构型,并在同样的研究条件下计算和分析了三个体系的自然电子布居(NPA)即电荷分布。得到相应的优化几何结构参数、NPA电荷、相互作用能量等。结果表明,所有优化体系均无虚频,结构稳定。Morin-Fe^(2+)配合物与O·―2的相互作用能表明,三种络合方式均对该自由基有良好的消除作用。相互作用能数值在基组重叠误差(BSSE)校正后分别为:7.075 kJ/mol(5,6元环配合物)、-32.832 kJ/mol(5元环配合物)、-59.612 kJ/mol(6元环配合物)。其中Fe^(2+)以六元环的方式与双分子Morin结合的方式与自由基的相互作用能最大,作用结果使得O·―2的NPA电荷增加最多,因此推测强相互作用的主导因素为电荷,这与前线轨道电子云分布一致。最高占据轨道(HOMO)中电子云集中分布在以Fe^(2+)为中心的六元环,分子骨架上共轭体系的电子云向金属中心迁移。最低空轨道(LUMO)中电子云集中分布在以Fe^(2+)为中心的六元环周围,呈现基本对称的分布形式,而金属中心与自由基上分布较少,这与自由基电荷增加相一致。

Electrochemical Multicomponent Cascade Radical Process Enabling Synthesis of lodomethyl Spiropyrrolidinyl-Oxindoles

A novel electrochemical multicomponent cascade reaction of indole-tethered alkenes with CF_(3)SO_(2)Na and n-BuaNI has been developed,which enables the rapid assembly of spiropyrrolidinyl-oxindoles in good yields.The experimental results and DFT calculations suggest that this reaction proceeds through the oxidation of CF_(3)SO_(2)Na,radical coupling with alkene,spirocyclization,oxidation of sulfinate,iodide substitution,and water coupling.This strategy features mild reaction conditions,easy-to-handle reactants,and good chemical yields.This finding not only enriches the research contents of indole-tethered alkenes but also provides a green strategy for the construction of spiropyrrolidinyl-oxindoles compared with the existing methodologies.

ESR STUDIES ON THE SEMIQUINONE RADICAL ANIONS OF HYPOCRELLIN B AND ITS DERIVATIVES AND THE PRODUCTION OF ^(1)O_(2),O_(2)^(█*)

Ⅰ. INTRODUCTIONHypocrellins are 3, 10-dihydroxyl-4, 9-perylenequinone derivatives. They are potent inhibitors of cancer cells. Besides 1O2 and O2, other radicals could also be involved in the effects of Hypocrellins on the photosensitization of erythrocyte membranes. The ESR signal with hyperfine structures could be obtained after illumination of Hypocrellin A, B (HA,

紫红薯糖蛋白体外抗氧化活性研究

研究紫红薯糖蛋白的体外抗氧化活性。使用水提醇沉方法、Sevage法除游离蛋白,用DEAE-52纤维素层析及SephadexG-75纯化制备糖蛋白。采用超氧阴离子自由基(O-2.)、羟基自由基(·OH)、1,1-二苯基-2-苯肼自由基(DPPH.)清除率测定法及还原力测定法评价紫红薯糖蛋白体外抗氧化活性。糖蛋白在0～640μg/mL内,均具有明显的抗氧化活性,随着质量浓度的增加活性增强;其中在紫红薯糖蛋白的质量浓度为640μg/mL时,对超氧阴离子自由基(O-2.)清除作用达到69.80%;对羟基自由基(.OH)的清除作用达到73.29%。

紫苏等4种天然色素抗氧化能力的比较

以紫苏、紫甘蓝、黑米、紫甘薯这4种天然色素为试验材料,从还原力、抗脂质过氧化和清除自由基等方面对它们的抗氧化能力进行了研究和评价。结果表明,这4种色素具有一定的还原能力;对亚油酸过氧化有抑制作用,在试验浓度范围内,最大抑制率分别为24.56%,33.04%,45.61%,54.39%;对DPPH自由基有明显的清除能力,最大清除率为92.59%,93.2%,78.4%,66.29%;对超氧阴离子也有一定的清除能力,最大清除率为46.85%,57.69%,41.2%,65.08%。紫苏、甘蓝、黑米、甘薯色素是优良的具有抗氧化功能的天然色素。

肉桂酸及其衍生物抗氧化活性研究

目的:研究肉桂酸及其衍生物等8种中草药有效成分对超氧阴离子自由基的清除和抑制脂质过氧化的作用和规律,以期为食品和药物等抗氧化剂的筛选和应用提供理论依据。方法:O2·测定采用改良的硝基四氮唑蓝-(NBT)还原法,微粒体脂质过氧化产物丙二醛(MDA)测定采用TBA分光光度法。结果:咖啡酸、氯原酸、连翘酯甙和阿魏酸对O2·具有较强的清除能力,对-羟基香豆酸、邻-羟基香豆酸和间-羟基香豆酸对O-2·的清除-能力较弱,肉桂酸则没有,清除O2·的能力强弱顺序为:咖啡酸>氯原酸>连翘酯甙>阿魏酸>对羟基香豆酸>邻-羟基香豆酸>间羟基香豆酸;对肝脏微粒体脂质过氧化产物MDA的形成具有抑制作用,作用的强弱关系与清除O2·能力基本一致。结论:除肉桂酸外,7种肉桂酸衍生物均具有抗氧化作用,而肉桂酸没有,进一步表明各-药物的抗氧化能力与其结构有明显的关系。结构—活性显示:-CHCHCOOH基团不是肉桂酸衍生物抗氧化的活性基团,而酚羟基是其抗氧化的必需基团;在肉桂酸-CHCHCOOH基团的对位含有酚羟基的化合物比在邻位或间位含有酚羟基化合物清除O2·活性强;在肉桂酸衍生物酚羟基的邻位有含孤对电子的杂原子取代基(-OH,-OCH3)时,-其清除O·的能力进一步提高。