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以钛酸四丁酯为原料 ,膨胀珍珠岩为载体 ,用溶胶 -凝胶法制备可漂浮于水面的负载型TiO2 。利用该负载型TiO2 对罗丹明B(RB)进行光催化脱色实验 ,结果表明 ,浸渍 3次的负载型TiO2 光催化活性最高 ,催化剂最佳用量为 5 0 0mg/10 0mLRB ,经 5h光照 ,对 10 0mL浓度为 1mg/L和 2 .5mg/LRB脱色率分别为 76 .6 7%和 4 7.2 7% ;该催化剂使用寿命长 ,2 5h后催化剂脱色性能没有减弱 ,可重复使用 ;经 8h光照 ,染料废水脱色效果好。 相似文献
43.
Quantification of joint effect for hydrogen bond and development of QSARs for predicting mixture toxicity 总被引:4,自引:0,他引:4
A QSAR model is successfully proposed to predict the toxicity effect on Photobacterium phosphoreum by nonpolar-narcotic-chemical mixtures and/or polar-narcotic-chemical mixtures. For nonpolar-narcotic-chemical mixtures and polar-narcotic-chemical mixtures, their corresponding hydrophobicity-based QSAR models are derived from regression analysis. Comparison of these two QSAR models make us believe that it is the joint effect of hydrogen bond in polar-narcotic-chemical mixture that leads to the difference between these two models. Such joint effect of hydrogen bond can be quantified as AMH and BMH by using the different partition coefficients of mixtures in various organic phase/water systems. And the regression analysis results convinced us that the introduction of AMH does improve the quality of the QSAR model with r2=0.948, S.E.=0.166 and F=745.201 at P=0.000 for total 84 mixtures. 相似文献
44.
Study of metabolites from the degradation of polycyclic aromatic hydrocarbons (PAHs) by bacterial consortium enriched from mangrove sediments 总被引:3,自引:0,他引:3
The PAH metabolites produced during degradation of fluorene, phenanthrene and pyrene by a bacterial consortium enriched from mangrove sediments were analyzed using the on-fiber silylation solid-phase microextraction (SPME) combining with gas chromatography–mass spectrometry (GC–MS) method. Seventeen metabolites at trace levels were identified in different PAH degradation cultures based on the full scan mass spectra. In fluorene degradation cultures, 1-, 2-, 3- and 9-hydroxyfluorene, fluorenone, and phthalic acid were detected. In phenanthrene and pyrene degradation cultures, various common metabolites such as phenanthrene and pyrene dihydrodiols, mono-hydroxy phenanthrene, dihydroxy pyrene, lactone and 4-hydroxyphenanthrene, methyl ester, and phthalic acid were found. The detection of various common and novel metabolites demonstrates that SPME combining with GC–MS is a quick and convenient method for identification as well as monitoring the real time changes of metabolite concentrations throughout the degradation processes. The knowledge of PAH metabolic pathways and kinetics within indigenous bacterial consortium enriched from mangrove sediments contributes to enhance the bioremediation efficiency of PAH in real environment. 相似文献
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本文详细介绍了铁在表生地球化学环境中的存在状态,亚铁的氧化动力学,铁微生物地球化学及铁在表生带迁移转化的环境学意义,强调了铁环境地球化学研究的重要性 相似文献
48.
采用极化曲线法研究了酸性蚀刻液阴、阳极电化学行为,并构建了离子膜电解反应体系,考察了在线再生酸性蚀刻液及回收铜的效果。结果表明,阳极氧化过程发生浓差极化,存在极限电流密度,Cu+含量越高,极限电流密度越大;阴极还原分4步反应进行,存在极限电流密度;强化溶液传质可有效提高阴、阳极极限电流密度,有利于避免电解过程中析出氯气和氢气;在线实验表明,通过监控阳极液ORP,可避免析出氯气;分步降低电流电解有利于避免析出氢气,形成致密的金属铜块;在电流为9~24A范围内分4步电解23.5h可再生酸性蚀刻液23.5L,同时电沉积回收510g铜,纯度高达99.98%。阴极电流效率达到95.2%,吨铜电耗3251kWh。电解过程中无氯气和氢气析出,无废液排放,表明膜电解法在线再生酸性蚀刻液具有良好的应用前景。 相似文献
49.
Distribution of elements in needles of Pinus massoniana (Lamb.) was uneven and affected by needle age 总被引:1,自引:0,他引:1
Kuang YW Wen da Z Zhou G Liu SZ 《Environmental pollution (Barking, Essex : 1987)》2007,145(3):730-737
Macronutrients (P, S, K, Na, Mg, Ca), heavy metals (Fe, Zn, Mn, Cu, Pb, Cr, Ni, Cd,) and Al concentrations as well as values of Ca/Al in the tip, middle and base sections, and sheaths of current year and previous year needles of Pinus massoniana from Xiqiao Mountain were analyzed and the distribution patterns of those elements were compared. The results indicated that many elements were unevenly distributed among the different components of needles. Possible deficiency of P, K, Ca, Mn and Al toxicity occurred in needles under air pollution. Heavy metals may threaten the health of Masson pine. Needle sheaths were good places to look for particulate pollutants, in this case including Fe, Cu, Zn, Pb, Cr, Cd and Al. 相似文献
50.
典型铬渣简易掩埋场铬渣及土壤铬污染特征和处置分析 总被引:6,自引:1,他引:6
通过钻孔采样分析,研究了典型铬渣简易掩埋场地下铬渣及土壤铬中Cr6 、总Cr的分布特征和污染状况,结果表明,铬渣简易掩埋场铬污染程度严重,引起了周边和地下深部较大面积的土壤污染,深度达到了地下的基岩.铬含量在土壤层剖面中分布呈现规律性变化,即随土壤深度增加,Cr6 、总Cr含量逐渐下降,但绝大多数超过了危险废物毒性鉴别标准.从铬污染程度上看,总体上存在铬渣>土壤>人工填土.在此基础上,提出了铬渣及污染土壤的处置方式,为铬渣污染治理和资源化利用提供科学依据. 相似文献