Total cobalt determination in human blood and synovial fluid using inductively coupled plasma-mass spectrometry: method validation and evaluation of performance variables affecting metal hip implant patient samples

Inductively coupled plasma with mass spectrometric detection (ICP-MS) has been used for clinical analysis of cobalt (Co) due to its sensitivity and specificity; however, media-specific validation studies are lacking. This study provides data on performance variables affecting differences between selected analytical platforms (Perkin Elmer and Agilent), tissue sample preparation, storage, and interferences affecting measurements in whole blood, serum, and synovial fluid. The limits of detection (LOD) range from 0.2–0.5 µg/L in serum and synovial fluid, and 0.6–1.7 µg Co/L in whole blood. The Agilent platform with collision reaction cell is more sensitive, while the Perkin Elmer platform with dynamic reaction cell demonstrates more polyatomic interferences near the LOD for serum and whole blood. Split sample analysis showed good accuracy, precision, and reproducibility between serum Co measurements using acid digestion or detergent dilution preparations for persons with metal hip implants or following supplement intake. The results demonstrated reliability of the ICP-MS methodology across the two analytical platforms and between two commercial laboratories for Co concentrations above 5 µg Co/L, but digestion procedures and polyatomic interferences may affect measurements in some media at lower concentrations. These studies validate the described ICP-MS methodology for clinical purposes with precautions at low cobalt concentrations (<5 µg Co/L).     

废气和废渣协同作用脱钠反应特性及机制研究

以氧化铝冶炼过程中排出的碱性固体废渣赤泥为研究对象,利用烟气中CO2对其进行了脱钠工艺的实验分析.研究了在不同pH、反应时间和温度下废气中CO2与废渣赤泥协同作用脱钠反应特性及机制,结果表明,赤泥脱钠反应过程是赤泥中钠基固体物质与CO2-H2O和OH--CO2系统协同作用的结果,脱钠过程与pH值、温度和反应时间有一定的反应规律.采用XRD和SEM方法对赤泥脱钠前后物料特性进行表征分析,结果表明赤泥中的碱性物质与CO2发生反应,赤泥脱钠后固相中的钠含量明显降低.通过合理的设计和适当的操作,可使赤泥脱钠率达70%以上,为低成本赤泥脱钠提供了一种有效的途径.     

双驱动反应器中热钾碱吸收二氧化碳的动力学研究

采用双驱动反应器研究了热钾碱吸收二氧化碳的反应动力学,根据双膜理论,应用CO_2-H_2O体系,实验首先对气相传质过程进行了研究,结果表明:当气相体积流量为80 m L·min~(-1)时,气相搅拌速度在100 r·min~(-1)时可认为气膜阻力消去.通过改变液相搅拌转速,研究了液相传质系数kL变化规律,获得了k_L的无因次关联式.根据热钾碱吸收CO_2反应机理,获得了宏观动力学方程,并结合溶液的非理想性,对速率方程中的浓度效应进行了校正,通过实验测定并进行了模型参数估值,各参数分别为:表观活化能E_(ob)=21.9308 k J·mol~(-1),表观反应级数n=0.1399,表观指前因子K'_0=1.1908×10~(-4)mol·m~(-2)·s~(-1)·Pa~(-1).在此基础上,通过计算获得了热钾碱吸收CO_2的本征动力学方程,各模型参数分别为:本征反应活化能E=59.57 k J·mol~(-1),指前因子k_0=2.1802×1011m~3·mol~(-1)·s~(-1).为进行整个过程反应机制的判断,计算了膜内转化系数γ,结果表明该值远大于2,可知CO_2吸收为快速反应过程,反应主要集中在膜内完成,并由此可知工业反应器选型应采用比相界面积较大的填料塔为优.     

UV/H2O2氧化降解克拉霉素的反应动力学及影响因素

克拉霉素用量大、检出频率高、生态风险大,已被欧盟列为优先监测污染物.针对传统污水处理厂难以完全去除克拉霉素的问题,主要研究了UV/H_2O_2降解克拉霉素的效果和反应动力学,探讨了pH、天然有机质(NOM)和水中共存阴、阳离子对UV/H_2O_2降解克拉霉素的影响.结果表明:单一UV对克拉霉素的光降解符合准一级反应动力学模型,其反应速率常数为0.0016 min~(-1).UV/H_2O_2对克拉霉素的降解符合准一级反应动力学模型,且克拉霉素的降解速率随H_2O_2浓度的增大而增大,在H_2O_2浓度为40 mmol·L~(-1)时,克拉霉素降解的反应速率常数为0.0284min~(-1).克拉霉素与·OH的二级反应速率常数为(2.36±0.20)×10~(10)L·mol~(-1)·s~(-1).碱性条件有利于克拉霉素的降解;NOM(2~10 mg·L~(-1))会抑制克拉霉素的降解,且随NOM浓度增大而增大;共存阴离子CO_3~(2-)对克拉霉素降解无影响,HCO_3~-、NO_3~-、Cl~-会抑制克拉霉素的降解,抑制程度的大小顺序为NO_3~-HCO_3~-Cl~-;共存阳离子Ca~(2+)、Mg2+、Cu~(2+)、Fe~(3+)会抑制克拉霉素的降解,抑制程度的大小顺序为Fe~(3+)Cu~(2+)Mg2+Ca~(2+).     

纳米磁铁矿/生物质炭催化对Fenton氧化降解苯酚的增强机理

以生物质炭负载纳米磁铁矿(nMBC)作为催化剂,采用非均相Fenton反应体系对模拟苯酚废水进行氧化降解处理研究,确定n MBC—Fenton法处理苯酚废水的最佳工艺条件,并揭示其强化机理。实验结果表明:对于质量浓度为50 mg/L的苯酚废水,其最佳降解条件为温度为45℃,pH为3.0,H_2O_2浓度为5 mmol/L,nMBC用量为2.0 g/L。反应进行20 min后,苯酚去除率可达约100%。nMBC剂量、废水初始pH和温度等因素均对处理效果有较大影响,其中pH决定苯酚去除率,而nMBC剂量是影响降解速率的主要因素。此外,nMBC—Fenton法催化氧化降解苯酚过程符合准一级动力学反应(R~2>0.97)。     

Intrinsic chemiluminescence production from the degradation of haloaromatic pollutants during environmentally-friendly advanced oxidation processes: Mechanism, structure–activity relationship and potential applications

The ubiquitous distribution of halogenated aromatic compounds(XAr) coupled with their carcinogenicity has raised public concerns on their potential risks to both human health and the ecosystem. Recently, advanced oxidation processes(AOPs) have been considered as an"environmentally-friendly" technology for the remediation and destruction of such recalcitrant and highly toxic XAr. During our study on the mechanism of metal-independent production of hydroxyl radicals(UOH) by halogenated quinones and H_2O_2, we found, unexpectedly, that an unprecedented UOH-dependent two-step intrinsic chemiluminescene(CL) can be produced by H_2O_2 and tetrachloro-p-benzoquinone, the major carcinogenic metabolite of the widely used wood preservative pentachlorophenol. Further investigations showed that, in all UOH-generating systems, CL can also be produced not only by pentachlorophenol and all other halogenated phenols, but also by all XAr tested. A systematic structure–activity relationship study for all 19 chlorophenolic congeners showed that the CL increased with an increasing number of Cl-substitution in general. More importantly, a relatively good correlation was observed between the formation of quinoid/semiquinone radical intermediates and CL generation. Based on these results, we propose that UOH-dependent formation of quinoid intermediates and electronically excited carbonyl species is responsible for this unusual CL production; and a rapid, sensitive,simple, and effective CL method was developed not only to detect and quantify trace amount of XAr, but also to provide useful information for predicting the toxicity or monitoring real-time degradation kinetics of XAr. These findings may have broad chemical, environmental and biological implications for future studies on halogenated aromatic persistent organic pollutants.     

生物淋滤联合类Fenton反应去除污染土壤中重金属的效果

针对我国南方地区广泛存在的土壤重金属污染问题,以广东韶关铅锌矿周边污染农田土壤为研究对象,探讨利用生物淋滤方法与生物淋滤联合类Fenton反应对土壤Cu、Zn、Cd和Pb的去除效果,并采用序列化学提取(SEC)方法,分析不同处理对土壤中4种重金属形态分布的影响.结果表明,经12 d生物淋滤Cu、Zn、Cd和Pb的去除率分别达到66.5%、55.1%、72.8%和35.6%,其中无机结合态重金属去除效果最好,固相中剩余重金属主要以稳定的残渣态形式存在.2 d生物淋滤联合类Fenton反应在优化的H_2O_2浓度(5 g·L-1)下,对上述4种重金属的去除率分别为55.6%、50.6%、60.7%和30.5%,低于12 d生物淋滤处理,但显著高于H_2SO_4酸化、2 d生物淋滤、化学Fenton反应等对照处理.生物淋滤联合类Fenton反应可以实现原土壤中残渣态、有机结合态和无机结合态等较稳定态重金属的有效去除,使处理后土壤中4种重金属Cu、Zn、Cd和Pb的含量分别低于50、200、0.3和250 mg·kg~(-1)的标准限值.该方法兼具生物淋滤高去除效率和Fenton反应快速处理等优势,对于修复重金属Cu、Zn、Cd和Pb等复合污染的土壤具应用前景.     

Chemical self-organization in self-assembling biomimetic systems

Far-from-equillibrium oscillating chemical reactions are among the simplest systems showing complex behaviors and emergent properties. This class of reactions is often employed to mimic and understand the mechanisms of a great variety of biological processes. In this context, pattern formation due to the coupling between reaction and transport phenomena represent an active and promising research area. In this paper, we present results coming from experiments where we tried to blend the structural properties of self-assembled matrixes (sodium dodecyl sulphate micelles and phospholipid bilayers) together with the evolutive peculiarities of the Belousov–Zhabotinsky reaction. A series of interesting dynamical behaviors, like spatio-temporal chaos, stationary patterns and segmented waves, were found in reaction–diffusion and reaction–diffusion–convection experiments.     

PREDICTIVE CAPABILITIES OF BATCH-EXTRACT EXPERIMENTS USING WATER FROM A COAL MINE1

ABSTRACT: The ability of batch-extraction experiments to predict postmining ground water quality was evaluated. As a basis for evaluation, mineralogical and water quality data were used to identify the geochemical reactions that controlled the major-ion chemistry in batch-extraction experiments. The experiments used water and spoil material collected from a surface-coal mine in the Powder River basin of northeast Wyoming. The batch-extraction experiments consisted of a 2:1 solid:liquid ratio of ground water and spoil material (by weight). The chemical composition of the resulting batch-extracts was determined after a contact time of 24 hours. Thermodynamically-favorable reactions included calcite precipitation, gypsum dissolution, and formation of kaolinite as a result of orthoclase feldspar hydrolysis. Three reaction models were consistent with the therinodynanuc and mineralogic data. In general, the extracts had smaller major-ion concentrations than did the water samples collected from the spoil aquifer. Correction ratios were calculated from these experiments and could be used in combination with additional batch-extractions at existing or future lease areas to predict the quality of the ground water after mining.     

Aniline removal by Photocatalytic reaction of iron(iii) mediated with dissolved organic matter

When light (> 370 nm) was allowed to interact with an aqueous solution containing dissolved organic matter (DOM) and Fe(III), removal of aniline (AN) was observed. This was due to the photocatalytic reaction of Fe(III) mediated by DOM. Syringic acid (SYA) and humic acid (HA) were used as DOM in the present study. The ¹⁵N‐NMR spectrum of the product mixture from the light irradiation of the SYA/Fe(III) system demonstrated that AN was covalently bound to SYA. The kinetics of AN removal were, therefore, interpreted by assuming covalent binding between DOM and AN. The amounts of covalent binding sites and the apparent second‐order rate constants could be evaluated, and the amounts of covalent binding sites decreased with the increases of the concentration of DOM. This is attributed that the polymerization of DOM by the photo‐oxidation competed with the covalent binding between AN and DOM.