Accumulation of cadmium,lead, and nickel by fungal and wood biosorbents

Native fungal biomass of fungiAbsidia orchidis, Penicillium chrysogenum, Rhizopus arrhizus, Rhizopus nigricans, and modified spruce sawdust (Picea engelmanii) sequestered metals in the following decreasing preference pb>Cd>Ni. The highest metal uptake was q_max = 351 mg Pb/gA. orchidis biomass. P.chrysogenum biomass could accumulate cadmium best at 56 mg Cd/g. The sorption of nickel was the weakest always at < 5 mg Ni/g. The spruce sawdust was modified by crosslinking, oxidation to acidic oxoforms, and by substitution. The highest metal uptake was observed in phosphorylated sawdust reaching q_max = 224 mg Pb/g, 56 mg Cd/g, and 26 mg Ni/g. The latter value is comparable to the value of nickel sorption by wet commercial resin Duolite GT-73. Some improvement in metal uptake was also observed after reinforcement of fungal biomass.     

Determination of urinary lead, cadmium and nickel in steel production workers

The determination of toxic metals in urine is an important clinical screening procedure. In this study, the aim of our investigation was to determine the concentrations of Pb, Cd, and Ni in urine samples under routine clinical laboratory conditions. To assess the reliability of these methods, critical factors such as detection limit(s), calibration range(s), cost, accuracy and precision were studied. The method was employed for the quantitative determination of lead, cadmium and nickel in urine samples from steel production and quality control (QC) workers and healthy unexposed controls. After pre-treatment with acids, the samples were digested via a microwave oven and the samples were determined by a graphite furnace atomic absorption spectrometry (GFAAS). Quality control for these procedures was established with the concurrent analysis of Standard Trace Metals 7879 Level II and NIST SRM 2670 (Toxic Elements in Freeze Dried Urine). The results indicate that urinary lead, cadmium and nickel levels of the exposed workers are significantly higher those of the controls. The possible connection of these elements with the etiology of disease is discussed. The results also show the need for immediate improvements in workplace ventilation and industrial hygiene practices.     

Investigation of effects of cadmium,lead, nickel and vanadium contamination on the uptake and transport processes in cucumber plants by TXRF spectrometry

Uptake and transport processes of some essential nutrient elements (K, Ca, Fe, Mn and Zn) in cucumber plants grown in contamination-free or in contaminated (10⁻⁵ M Cd, Ni, Pb or V) nutrient solutions containing iron in the chemical form of Fe(III)-citrate, Fe(III)-EDTA or Fe-chloride were studied by total reflection X-ray fluorescence spectrometry (TXRF). The root samples were dissolved using a microwave assisted acidic digestion procedure, while the xylem sap samples were directly analysed after addition of internal standard. It was established that the accumulation in the roots and the transport rate of the four heavy metals investigated increase in order of V<Ni≪Cd<Pb and V≪Pb<Cd<Ni, respectively. Due to the relatively low accumulation and transport of V in the plant it has the smallest influence on the uptake and transport of the essential elements. Cd hampers the water uptake and thereby the amount of all transported essential elements, and in addition results in higher accumulation of Ca, Fe and Zn in the roots. Pb contamination leads to a drastic reduction of Ca accumulated in the roots and mostly a slight increment in the transport of the essential nutrient elements investigated. Ni contamination hinders the transport of K and Zn, and leads to a higher accumulation of Mn in the roots. The chemical form of iron and hereby the presence of complex forming agents play an important role first of all for the uptake and transport processes of Fe and K.     

Cross contamination of lead and cadmium during dry ashing of food samples

Common white sugar was ashed in a muffle furnace under controlled heating at 450 degrees C. Together with these samples, sugar with added amounts of Pb and Cd (20, 50 micro g) was mineralized in the same furnace. Depending on the absolute amount of Pb and Cd present in the furnace, an increase in the 'blank' values of the unspiked sugar samples was found. The same effect was observed when reference material containing natural amounts of Pb and Cd (TORT-1, Lobster) was present in the furnace. Although the results strongly depend on the blank levels of the muffle furnace, cross contamination effects could be demonstrated for both elements. The investigations demonstrate, that at a temperature of 450 degrees C, both Cd and Pb are lost during ashing of samples. The type of matrix in a sample with high contents of Pb and Cd has no significant effect on the volatility of these elements. The vapor lost from a sample containing high amounts of Pb and Cd will falsify the concentration in low level samples present in the furnace.     

Separations involving palladium: Separation of lead,bismuth, cadmium,thallium, copper,cobalt and nickel from palladium

It has been shown that 1% dimethylglyoxime solution in alcohol can be efficiently used to separate quantitatively palladium from other metals of the copper group, as indicated in the new and more comprehensive scheme of qualitative analysis.     

Water-vapor pressure and thermodynamics of the dehydration of manganese,nickel, cadmium,and lead perchlorate hydrates

The water-vapor pressure has been measured by a static method, the temperature limits for existence have been determined, and the parameters of the equation lgp [Torr]=b —a/T have been calculated for the following crystal hydrates: Mn(ClO₄)₂ · 2H₂O (90–130°C, a=3527.0,b=8.487), Ni(ClO₄)₂ · 4H₂O (60–100°C,a=3606.7,b=9.704), Ni(C1O₄)₂ · 2H₂O (110–160°C,a = 4261.7,b = 10.103), Cd(ClO₄)₂ · 6H₂O (25–58.2°C,a = 3143.7,b = 9.356), Cd(ClO₄)₂ · 2H₂O (90–144.8°C,a=3823.3,b = 9.472), Pb(ClO₄)₂ · 3H₂O (10–47°C,a = 2932.9,b = 9.391 and 47–81.5°C,a = 2448.1,b=7.877), Pb(ClO₄)₂ · H₂O (60–102.4°C,a=3610.2,b = 9.857). A hitherto unknown metastable hydrate Cd(ClO₄)₂ · 4H₂O with a phase transition at 30.9°C (20–30.9°C,a = 3669.5,b = 11.343 and 30.9–63.7°C,a=3058.6,b = 9.339) has been detected.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 466–470, March, 1993.     

Polarographic determination of cadmium, lead, nickel, thallium and uranium(VI) in isoquinoline formate

Summary The polarographic behaviour of Cd, Pb, Ni, Tl and U(VI) has been described in 0.1 M isoquinoline formate as base electrolyte. In all cases well defined reversible waves were obtained and determinations are possible in the presence of Mo, Co, Zn, Mn, Te, In, Se, Fe, Cr, V, Th, Zr, As, Sb, Ag, Hg and Cu.

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Polarographische Bestimmung von Cadmium, Blei, Nickel, Thallium und Uran(VI) in Isochinolinformiat

Zusammenfassung Das polarographische Verhalten von Cd, Pb, Ni, Th. und U(VI) in 0,1 M Isochinolinformiatlösung wird beschrieben, Bestimmungsmöglichkeiten werden aufgezeigt. In allen Fällen werden gut definierte reversible Stufen erhalten. Folgende Elemente stören nicht: Mo, Co, Zn, Mn, Te, In, Se, Fe, Cr, V, Th, Zr, As, Sb, Ag, Hg, Cu.

     

Direct electrochemical synthesis of cobalt,nickel, copper,zinc, cadmium,tin and lead zincon complexes

Transition Metal Chemistry - Main group and transition metal complexes of zincon-(2-hydroxy-5-sulphonyl azobenzylidene hydrazinobenzoic acid) have been prepared by an electrochemical technique...     

能量色散型X射线荧光光谱法测定聚合物材料中镉和铅含量

提出了能量色散型X射线荧光光谱测定聚合物材料中镉和铅的测试分析方法及制样技巧。按照仪器分析条件测定同时含有镉和铅的6块不同浓度级别的标准物质来建立校准工作曲线,其线性范围分别在250ug·g-1、1100ug·g-1以内。镉和铅的方法检出限依次为4.7ug·g-1、4.1ug·g-1。该方法应用于测定欧洲标准物质ERM-EC680和ERM-EC681k,其镉和铅的实际测定值与标准物质证书的标称值相符,测定实际样品中的镉和铅的回收率介于90~110%。该方法测定标准物质和实际样品中镉和铅的精密度均小于10%。     

Determination of cadmium, lead, iron, nickel and chromium in selected food matrices by plasma spectrometric techniques

In the frame of a study aimed at investigating the transfer of metal contaminants through the food chain and the effects of food processing, five elements, namely Cd, Pb, Fe, Ni and Cr, were accurately determined in (i) durum wheat grain and derived products, (ii) wheat-based reference materials, (iii) drinking water, used both as an ingredient and for technological purposes in the investigated industrial process. Microwave closed vessel digestion was selected as the dissolution technique for solid samples, whereas water samples were acidified with ultrapure nitric acid and analysed directly. As several analytes had to be quantified at trace or ultratrace levels, inductively coupled plasma mass spectrometry (ICP-MS) was resorted to for analytical determinations. Overall, this straightforward analytical approach enabled to detect the often small changes in element concentration associated with the different technological steps of processing. Nevertheless, detection of heavily interfered elements, especially Cr, as well as analyte quantification at ultratrace-level level in water, posed analytical challenges that required suited analytical solutions.Changes in the sample introduction system and complementary use of inductively coupled plasma atomic emission spectrometry (ICP-AES) straightforwardly overcame the difficulties in determining the analytes in the selected food matrixes. The benefits of ultrasonic nebulization in reducing the effects of problematic spectral interferences were demonstrated. Overall, a robust and high-throughput analytical method was outlined.     

Anodic stripping voltammetric determination of lead and cadmium in soil extracts

Two single-step extraction procedures validated by BCR, extraction with 0.43 mol dm⁻³ acetic acid and 0.05 mol dm⁻³ EDTA, are used for assessing bioavailable species of Pb and Cd in soils. After an extensive study of interferences of humic substances and using standard additions procedures, the extractable contents of Pb and Cd have been determined by DPASV directly in soil extracts with a good reproducibility (RSD varied from 1.0 to 7.9 %). Pb(II) and Cd(II) were released from complex in EDTA extracts by pH adjustment to 1 with 1 mol dm⁻³ HCl. The results were compared with those obtained with atomic absorption spectrometry and indicated reasonable agreement of both methods. Exchangeable forms represented 0.2 to 3.3 % and 13.0 to 63.6 % of total content of Pb and Cd in soils, respectively. EDTA extraction released from soils 7.9 to 29.9 % and 33.5 to 59.6 % of total content of Pb and Cd, respectively.     

Spectrophotometric study of cobalt, nickel, copper, zinc, cadmium and lead complexes with murexide in dimethylsulphoxide solution

The complexation reactions between murexide and Co(2+), Ni(2+), Cu(2+), Zn(2+), Cd(2+) and Pb(2+) ions have been studied spectrophotometrically in dimethylsulphoxide solution at 25 degrees . The stoichiometry of the complexes was found to be 1:1. The stability constants of the complexes were determined, and found to follow the Irving-Williams rule for the cations of the first transition series. In dimethylsulphoxide solution, the complexes are much more stable than those in aqueous solution.     

Thermodynamic study of the system cadmium - zinc,cadmium - lead,cadmium - tin,bismuth - cadmium,tin - zinc,and lead - tin

Russian Chemical Bulletin -     

Influence of the clay and the nickel content in catalysts for vegetable oil hydrogenation

Nickel catalysts prepared using two different clays as support, natural bentonite and palygorskite, and with different nickel contents have been tested in the hydrogenation of a sunflower oil. The influence of the clays, and of the nickel-bentonite ratio on the activity, selectivity and trans-isomer formation was investigated. Previously it was establised that no diffusional limitations were controlling the rate. Bentonite with the highest nickel content was the most active and selective catalysts.     

Sorption of lead, copper, cadmium, zinc, and nickel by marine algal biomass: characterization of biosorptive capacity and investigation of mechanisms

The marine algae Sargassum sp., Padina sp., Ulva sp., and Gracillaria sp., harvested locally, were investigated for their biosorption performance in the removal of lead, copper, cadmium, zinc, and nickel from dilute aqueous solutions. It was found that the biosorption capacities were significantly affected by solution pH, with higher pH favoring higher metal-ion removal. Kinetic and isotherm experiments were carried out at the optimal pH: at pH 5.0 for lead and copper, and at pH 5.5 for cadmium, zinc, and nickel. The metal removal rates were rapid, with 90% of the total adsorption taking place within 60 min. Sargassum sp. and Padina sp. showed the highest potential for the sorption of the metal ions, with the maximum uptake capacities ranging from 0.61 to 1.16 mmol/g for Sargassum sp. and 0.63 to 1.25 mmol/g for Padina sp. The general affinity sequence for Padina sp. was Pb>Cu>Cd>Zn>Ni, while that for Sargassum sp. was Pb>Zn>Cd>Cu>Ni. XPS and FTIR analysis of Sargassum sp. and Padina sp. revealed the chelating character of the ion coordination to carboxyl groups. It was confirmed that carboxyl, ether, alcoholic, and amino groups are responsible for the binding of the metal ions.     

A comparison of sequential extraction procedures for fractionation of arsenic,cadmium, lead,and zinc in soil

Twelve soil samples differing in physicochemical properties and total element contents were extracted by three sequential extraction procedures to determine As, Cd, Pb, and Zn bound to individual soil fractions and are defined by individual operational procedures. In the case of arsenic, two additional sequential extraction schemes were designed entirely for fractionation of soil containing arsenic were tested. The results confirmed that determination of element proportions bound to individual soil fractions is strongly dependent on the extracting agent and/or procedure applied within individual extracting schemes. As expected, absolute values of the elements released among the individual extracting procedures are weakly comparable. More reliable results were determined for the more mobile soil elements i.e. cadmium and zinc, in the fractions characterizing the most mobile proportions of investigated elements where significant correlations with basic soil characteristics were observed. In contrast, ambiguous results were observed for As and Pb, for both the individual extraction procedures and the effect of the soil characteristics. Regardless of the studied element, the poorest results were determined for reducible and oxidizable soil fractions. The application of at least two independent procedures or modification of the extraction scheme according to element investigated and/or particular soil characteristics can also be helpful in definition of element pattern in soils in further research.     

石墨炉原子吸收法测定土壤中铅、镉、钴、锑、铍

建立石墨炉原子吸收法测定土壤中铅、镉、钴、锑、铍含量的方法。优化了石墨炉原子吸收光谱法测定条件,在最佳实验条件下,采用硝酸-盐酸-氢氟酸-双氧水混合酸体系微波消解土壤样品,选用抗坏血酸-硝酸镁混合溶液为基体改进剂。铅、镉、钴、锑、铍的质量浓度在各自的范围内与吸光度成良好的线性关系,相关系数均大于0.999,各元素的检出限为0.008~0.06 μg/g。样品加标回收率为90.5%~104.0%,测定结果的相对标准偏差均小于2.5%(n=6)。该方法样品前处理简便,灵敏度高,检出限低,测定结果准确、可靠,可用于土壤中铅、镉、钴、锑、铍的测定。