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821.
武伟男 《辽宁城乡环境科技》2014,(11):61-63
采用硫离子选择电极法快速检测油田水中硫化物,优化了操作条件,在溶液pH值大于11.5和中速搅拌(800 r/min左右)条件下,单个样品分析时间少于15 min.空气中的氧对测定结果干扰明显,通过取样时加入硫化物稳定剂方法可消除空气中氧的影响.方法的精密度小于4.0%,与碘量法相比,相对偏差小于15%,方法检测下限为0.35 mg/L. 相似文献
822.
823.
Due to the unique antibacterial activities, silver nanoparticles (AgNPs) have been extensively used in commercial products. Anthropogenic activities have released considerable AgNPs as well as highly toxic silver ion (Ag+) into the aquatic environment. Our recent study revealed that ubiquitous natural organic matter (NOM) could reduce Ag+ to AgNP under natural sunlight. However, the toxic effect of this process is not well understood. In this work, we prepared mixture solution of Ag+ and AgNPs with varied Ag+% through the sunlight-driven reduction of Ag+ by NOM and investigated the acute toxicity of the solutions on Daphnia magna. Formation of AgNPs was demonstrated and characterized by comprehensive techniques and the fraction of unconverted Ag+ was determined by ultrafiltration-inductively coupled plasma mass spectrometry determination. The formation of AgNPs enhanced significantly with the increasing of solution pH and cumulative photosynthetically active radiation of sunlight. The toxicity of the resulting solution was further investigated by using freshwater crustacean D. magna as a model and an 8 hr-median lethal concentration (LC50) demonstrated that the reduction of Ag+ by NOM to AgNPs significantly mitigated the acute toxicity of silver. These results highlight the importance of sunlight and NOM in the fate, transformation and toxicity of Ag+ and AgNPs, and further indicate that the acute toxicity of AgNPs should be mainly ascribed to the dissolved Ag+ from AgNPs. 相似文献
824.
A 1-dodecanethiol-based phase-transfer protocol is developed for the extraction of noble metal ions from aqueous solution to a hydrocarbon phase, which calls for first mixing the aqueous metal ion solution with an ethanolic solution of 1-dodecanethiol, and then extracting the coordination compounds formed between noble metal ions and 1-dodecanethiol into a non-polar organic solvent. A number of characterization techniques, including inductively coupled plasma atomic emission spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis demonstrate that this protocol could be applied to extract a wide variety of noble metal ions from water to dichloromethane with an efficiency of > 96%, and has high selectivity for the separation of the noble metal ions from other transition metals. It is therefore an attractive alternative for the extraction of noble metals from water, soil, or waste printed circuit boards. 相似文献
825.
826.
吐鲁番市地表水水化学特征变化分析 总被引:5,自引:1,他引:4
在将1958年吐鲁番市地表水质检测资料与2013—2014年实地检测结果对比的基础上,综合运用数学统计、三角组分图、Gibbs图等方法,分析研究了吐鲁番市地表水化学特征的变化情况.结果表明,2013—2014年吐鲁番市地表水较1958年相比,TDS、硬度上升幅度超过一倍,SO2-4、Mg2+、Na+均上升,HCO-3、Ca2+下降.水化学类型由HCO-3型转变为HCO-3-SO2-4型;离子中Ca2+、HCO-3、TDS三者之间具有显著相关性转变为SO2-4、K++Na+、和TDS之间相关性显著;地表水在1958年主要受岩石风化作用的影响,而在2013—2014年受蒸发结晶作用的控制更加地显著,且受人为作用的影响明显地增强. 相似文献
827.
基于脱氧核酶的水中铀酰离子荧光检测方法研究 总被引:1,自引:1,他引:0
为了实现对于水中铀酰离子的快速灵敏检测,本研究基于脱氧核酶(DNAzyme)对铀酰离子的高特异识别能力及荧光共振能量转移(FRET)的信号产生原理,建立了铀酰离子的荧光检测方法.结果发现,在铀酰离子存在的条件下,两端分别标记荧光基团和淬灭基团的底物链被标记淬灭基团的酶链特异性切断,释放标记荧光基团的底物链片段,使得体系的荧光信号强度得到提高.通过底物链与酶链的比例、浓度及反应时间的优化,提高了检测方法的灵敏性,结果显示,本方法对于铀酰离子的检测限可达到0.7 nmol·L~(-1)(3S/N),并在4~20 nmol·L~(-1)之间保持良好的线性检测范围,整个检测过程仅需6 min即可完成.本检测方法具有良好的选择性,常见的金属离子铜、铅、汞、砷、镁、钙等对于检测结果无明显干扰作用.对清华大学饮用水及自来水的加标回收率实验结果显示,加标回收率分别为98.0%~107.8%和90.0%~108.0%.本研究为今后铀酰离子在实际环境水体中的检测奠定了基础. 相似文献
828.
采用沉淀法合成了纳米级二氧化锆,利用SEM、XRD技术,对纳米ZrO_2进行微观形貌和粒径分析,探讨了吸附时间、吸附温度、pH值以及Pb~(2+)初始浓度对吸附的影响,分析了吸附热力学性质和动力学特性,初步探讨了吸附机理。研究结果表明:在吸附温度为40℃,Pb~(2+)初始浓度为10 mg/L,pH为4.5时,吸附反应40 min后,最大吸附量为17.8 mg/g;纳米ZrO_2对Pb~(2+)吸附等温线符合Langmuir模型,其吸附动力学过程以准二级动力学方程拟合效果最好;温度在303~323 K时,纳米ZrO_2吸附Pb~(2+)的吉布斯自由能ΔG~o<0、焓变ΔH~o<0、熵变ΔS~o<0,表明纳米ZrO_2对Pb~(2+)的吸附是一个自发放热过程。 相似文献
829.
Daiane Tomacheski Michele Pittol Douglas Naue Simões Vanda Ferreira Ribeiro Ruth Marlene Campomanes Santana 《环境科学学报(英文版)》2017,29(6):230-239
In order to reduce the level of transmission of diseases caused by bacteria and fungi, the development of antimicrobial additives for use in personal care, hygiene products, clothing and others has increased. Many of these additives are based on metals such as silver and titanium. The disposal of these products in the environment has raised concerns pertaining to their potential harmfulness for beneficial organisms. The objective of this study was to evaluate the influence of the shape, surface chemistry, size and carrier of three additives containing silver and one with titanium dioxide (TiO2) on microcrustacean survival. Daphnia magna was used as a bioindicator for acute exposure test in suspensions from 0.0001 to 10,000 ppm. Ceriodaphnia dubia was used for chronic test in TiO2 suspensions from 0.001 to 100 ppm. D. magna populations presented high susceptibility to all silver based additives, with 100% mortality after 24 hr of exposure. A different result was found in the acute experiments containing TiO2 suspensions, with mortality rates only after 48 hr of incubation. Even on acute and chronic tests, TiO2 did not reach a linear concentration-response versus mortality, with 1 ppm being more toxic than 10,000 ppm on acute test and 0.001 more toxic than 0.01 ppm on chronic assay. Silver based material toxicity was attributed to silver itself, and had no relation to either form (nano or ion) or carrier (silica, phosphate glass or bentonite). TiO2 demonstrated to have a low acute toxicity against D. magna. 相似文献
830.