粉煤灰增强超声/H2O2降解左氧氟沙星的实验研究

研究粉煤灰对超声/H2O2体系降解左氧氟沙星的增强效果,考察了粉煤灰添加量、H2O2浓度、溶液初始pH值、左氧氟沙星初始浓度等对降解效果的影响.结果表明,与单独超声,H2O2氧化,超声/H2O2,超声/粉煤灰,粉煤灰/H2O2氧化相比,粉煤灰有效增强了超声/H2O2体系对左氧氟沙星的降解,降解反应符合一级反应动力学.粉煤灰添加量为1.5g/L,H2O2浓度为15.0mmol/L,pH=7.16,超声功率325W,左氧氟沙星初始浓度20mg/L,反应160min,左氧氟沙星的去除率达到99.12%,TOC去除率为17.37 %.利用荧光探针法对不同体系产生的·OH浓度进行了分析比较,粉煤灰作为非均相催化剂,主要在于发生类Fenton反应.采用HPLC/MS/MS方法对3种反应产物进行了分析,结果表明左氧氟沙星主要是通过喹诺酮环失去-C2,哌嗪环去亚甲基化以及·OH进攻喹诺酮环发生降解.     

NO和H2O2对大豆幼苗铝毒害的缓解效应及其相互作用

NO和H₂O₂作为信号分子参与植物对非生物胁迫的响应,为了确定NO和H₂O₂介导的大豆耐铝作用以及二者的交互作用,以浙春3号大豆为材料,分析了铝毒胁迫下根尖内源及外源NO和H₂O₂对大豆铝毒的缓解效应,并研究了NO和H₂O₂代谢相关酶的活性变化, 其中外源NO由SNP(亚硝基铁氰化钠,Na₂[Fe(CN)₅NO]·2H₂O)提供. 结果显示:Al处理显著抑制大豆根生长,促使Al在根尖积累并显著提高大豆根尖内源w(NO)和w(H₂O₂). 在H₂O₂₊Al、SNP+Al和H₂O₂₊SNP+Al处理下,大豆根相对伸长率比单独Al处理下分别升高了64.6%、63.5%和69.5%,根尖w(Al)则分别减少了34.6%、36.8%和32.9%,表明NO和H₂O₂对铝毒害均具有缓解作用.外源NO能够促使根尖内源H₂O₂显著积累,降低POD(过氧化物酶)活性,而外源H₂O₂对内源根尖w(NO)无影响.NO和H₂O₂在缓解铝毒的信号途径中存在信号互作,NO处于H₂O₂的上游,其通过POD活性调节内源w(H₂O₂).      

Effects of cucl2 on UV‐mutagenesis and on DNA damage in a restriction fragment of E. Coli gpt∗

CuCl₂ does not cause Trp⁺ reversion in E. coli WP2. However, when the bacteria are exposed to CuCl₂ and UV‐irradiated, a greater than 3‐fold enhancement of mutagenesis (compared to UV alone) is seen at 30 μMCuCl₂, and significant enhancement is seen even at 3 μM. The mechanism for this comutagenic effect was studied using a restriction fragment of the E. coli gpt gene. Whereas UV or CuCl₂ alone caused few strand breaks, UV + CuCl₂ induced breaks at every site. This reaction was blocked by KI, a free radical scavenger. While UV alone induced alkali‐labile sites, UV+ CuCl₂ induced many more such sites and altered the sequence specificity. We suggest that at least some of the comutagenic effect might be due to hydroxyl radical formed via a Fenton reaction.     

Hydrogen sulfide removal by iron containing activated carbon

Activated carbon modified by impregnation with iron (III) chloride solution (Fe‐ACs) were studied to try to raise their adsorption capacity for hydrogen sulfide, a malodorous substance.

The surface area and pore volume of activated carbon were decreased by impregnation, but the amount of hydrogen sulfide adsorbed onto Fe‐AC was larger than that onto raw activated carbon (R‐AC). In particular, a large increase of the amount adsorbed onto Fe‐AC was noted at low equilibrium pressure. It was assumed that the increase of amount of hydrogen sulfide adsorbed onto Fe‐AC was due to the chemical interaction between iron (III) chloride on the pores in addition to the physical adsorption onto pores of activated carbon. Fe‐AC shows a high selectivity for hydrogen sulfide.     

Total peroxides in rainwater at two mountainous sites and in Mexico City,Mexico

Rainwater samples were collected in the western sector of Mexico City (MC) and at Rancho Viejo (RV), 80 km west-south-west of MC, from 2001 to 2005, and Orizaba City (OC), about 90 km from the Gulf of Mexico, where rainwater collections were only possible on some weekends in 2001. Rainwater samples were treated in the field, and analysed by fluorescence at the laboratory. The volume-weighted mean concentration (VWMC) of H₂O₂ was 13.2 μM at RV, and 11.2 μM in MC, for the period 2001–2005. The highest VWMC was observed in OC (21.6 μM). The VWMCs for each year were 9.5, 14.4, 11.5, 16.7, and 14.3 μM at RV, and 12.2, 12.2, 14.3, 11.8, and 9.9 μM in MC, for 2001–2005, respectively. Hydrogen peroxide in rainwater correlated significantly and negatively with sulfate in both MC and RV, but not, however, in OC. This study confirmed that H₂O₂ concentration in rainwater is controlled by a complex combination of rain intensity, washout processes and in-cloud formation of H₂O₂, acting simultaneously. This was suggested by the fact that rain intensity seemed to predominate in certain rain fractions of a rain event, while washout processes seemed to predominate in other fractions of the same rain event.     

黄孢原毛平革菌的生长及降解石油条件的优化

在限氮振荡的条件下研究了藜芦醇、Tween-80、草酸、H2O2对黄孢原毛平革菌(P.C.菌)的生长量和石油降解性能的影响。实验结果表明:藜芦醇质量浓度低于0.05 g/L时促进P.C.菌的生长,高质量浓度时抑制P.C.菌的生长,石油降解率随藜芦醇质量浓度增加先升高后下降;Tween-80质量浓度低于7 mg/L时,P.C.菌生长量和石油降解率均随Tween-80质量浓度增大而增加,Tween-80质量浓度大于其临界胶束浓度时,P.C.菌生长量和石油降解率均低于未加Tween-80时;添加草酸抑制P.C.菌的生长,草酸质量浓度为35 mg/L时石油降解率最高,草酸质量浓度为350 mg/L时石油降解率低于未加草酸时;加入H2O2的体系中,石油降解率明显高于无H2O2体系。     

水力空化强化H2O2氧化降解水中苯酚的研究

采用水力空化强化H₂O₂降解水中苯酚,考察入口压力,ρ(H₂O₂)和溶解气体等因素对苯酚降解的影响;比较了水力空化方法和超声空化方法降解水中苯酚的能耗效率.研究表明:苯酚降解率随着入口压力的增大而增大,入口压力从1.0×105 Pa增大到3.5×105 Pa时,相应地苯酚降解率从17.6%增加到47.6%;在一定条件下,ρ(H₂O₂)有一个最佳值;不同的溶解气体对苯酚降解效果的影响不同,O₂的效果比N₂好.分析ρ(H₂O₂)和溶解气体对苯酚降解效果的影响及苯酚降解中间产物的分布表明,羟基自由基的产生是苯酚降解的主要原因,水力空化的能量利用率是超声空化的5.4倍.      

有机废水处理生物制氢技术

研究了利用有机废水发酵作用制取廉价氢气技术,并研制出厌氧活性污泥高效生物制氢反应器。以白脱糖、糖蜜和淀粉为供氢体,最大产氢能力达10.4m³H₂/m³反应器·d,发酵气中仅含48％H2和52％CO₂。该项技术已具有进一步开发价值。     

过氧化钙的制备及其在废水处理中的应用

开发出一种过氧化钙常温合成新工艺。在氯化铵与过氧化氢质量比为10／130、采用稳定剂ⅠA和稳定剂ⅡB的条件下,使氢氧化钙与过氧化氢反应合成过氧化钙,其收率为35．9％,纯度为72．3％。用制得的过氧化钙去除机械工业废水中的重金属离子,在室温、过氧化钙用量0．1％～0．2％、处理时间30min、处理过程中不调整pH的条件下,含锰35．58μg／mL、铜67μg／mL、锌31．3μg／mL、铬43．56μg／mL(均为质量浓度)的废水经一次处理后,锰、铜、锌浓度和pH均达到国家一级水排放标准,铬的一次去除率达到39％以上。     

TiO2光催化降解有机污染物的协同效应研究

微量的强氧化剂H2O2、O3引入纳米TiO2光催化体系能够极大地提高有机污染物氧化降解效率.本文通过对这一效应促进有机物降解的相关文献综述,探讨论述了协同效应产生的机理以及影响因素,并就其将来研究与实际污染物处理应用提出了新思路.