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A pyrolysis method was employed to recycle the metals and brominated compounds blended into printed circuit boards. This research investigated the effect of particle size and process temperature on the element composition of IC boards and pyrolytic residues, liquid products, and water-soluble ionic species in the exhaust, with the overall goal being to identify the pyrolysis conditions that will have the least impact on the environment. Integrated circuit (IC) boards were crushed into 5-40 mesh (0.71-4.4mm), and the crushed particles were pyrolyzed at temperatures ranging from 200 to 500 degrees C. The thermal decomposition kinetics were measured by a thermogravimetric (TG) analyzer. The composition of pyrolytic residues was analyzed by Energy Dispersive X-ray Spectrometer (EDS), Inductively Coupled Plasma Atomic Emission Spectrometer (ICP-AES) and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). In addition, the element compositions of liquid products were analyzed by ICP-AES and ICP-MS. Pyrolytic exhaust was collected by a water-absorption system in an ice-bath cooler, and IC analysis showed that the absorbed solution comprised 11 ionic species. Based on the pyrolytic kinetic parameters of TG analysis and pyrolytic residues at various temperatures for 30 min, the effect of particle size was insignificant in this study, and temperature was the key factor for the IC board pyrolysis. Two stages of decomposition were found for IC board pyrolysis under nitrogen atmosphere. The activation energy was 38-47 kcal/mol for the first-stage reaction and 5.2-9.4 kcal/mol for the second-stage reaction. Metal content was low in the liquid by-product of the IC board pyrolysis process, which is an advantage in that the liquid product could be used as a fuel. Brominate and ammonium were the main water-soluble ionic species of the pyrolytic exhaust. A plan for their safe and effective disposal must be developed if the pyrolytic recycling process is to be applied to IC boards.
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PMID:Pyrolysis characteristics of integrated circuit boards at various particle sizes and temperatures. 1746

Trace elements often accumulate in keratin-rich tissues. Hair, nails, and horns grow steadily but once formed are metabolically inactive and provide an archive of trace element exposure when analyzed in segments. Here we demonstrate the use of laser ablation ICP-MS for the high-resolution monitoring of trace elements in the horns of seaweed-eating sheep from North Ronaldsay, which live on grass only during lambing time. Due to this peculiar husbandry/dietary pattern and the fact that seaweed is rich in arsenic and iodine, we hoped to use iodine and arsenic as markers for seaweed ingestion. Cross sections and scans along the growing axis (representing the first 8-10 months of the sheep's life) revealed that these elements were not homogeneously distributed in the horn, with arsenic representing the amount of seaweed intake. The scans show the periods in which the lambs were fed on milk and grass and the change to seaweed ingestion with the successive replacement of milk with seaweed; this was supported by the carbon and nitrogen isotope signatures (delta13C and delta15N) of the horn and the arsenic speciation in the horn. The period of low arsenic accumulation in the horn had terrestrial isotope signatures and accumulated arsenic of mainly inorganic origin. The period of high arsenic accumulation was characterized by isotope signatures of marine origin, and the majority of accumulated arsenic in the horn was the main arsenosugar metabolite dimethylarsinic acid. Although we have investigated only four different horns of individual sheep, this study shows that arsenic is not significantly transported with milk. However, the high concentration of arsenic in the oldest part of the horn, which was formed in utero, points to a relatively high placental transport of arsenic while the ewe was eating seaweed. In contrast to arsenic, iodine is transported not only through milk ingestion but also through the placenta in large quantities.
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PMID:Monitoring the arsenic and iodine exposure of seaweed-eating North Ronaldsay sheep from the gestational and suckling periods to adulthood by using horns as a dietary archive. 1753 23

Long-range transboundary air pollution has caused severe environmental effects in Europe. European air pollution abatement policy, in the framework of the UNECE Convention on Long-range Transboundary Air Pollution (LRTAP Convention) and the European Union Clean Air for Europe (CAFE) programme, has used critical loads and their exceedances by atmospheric deposition to design emission abatement targets and strategies. The LRTAP Convention International Cooperative Programme on Modelling and Mapping Critical Loads and Levels and Air Pollution Effects, Risks and Trends (ICP M&M) generates European critical loads datasets to enable this work. Developing dynamic nitrogen flux models and using them for a prognosis and assessment of nitrogen effects remains a challenge. Further research is needed on links between nitrogen deposition effects, climate change, and biodiversity.
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PMID:Modelling and mapping long-term risks due to reactive nitrogen effects: an overview of LRTAP convention activities. 1806 83

Synthetic zeolites were studied in order to investigate their ability to encapsulate and to release drugs. In particular, a zeolite X and a zeolitic product obtained from a cocrystallization of zeolite X and zeolite A were examined. These materials were characterized by chemical analyses (ICP-AES), X-ray diffraction, nitrogen adsorption isotherm, scanning electron microscopy, laser diffraction, and infrared spectroscopy. Since ketoprofen was chosen as a model drug for the formulation of controlled-release dosage forms, it was encapsulated into these two types of synthetic zeolites by a soaking procedure. Drug-loaded matrices were then characterized for entrapped drug amount and thermogravimetric behavior. In both types of activated zeolites, the total amount of ketoprofen (800 mg) was encapsulated in 2 g of matrix. By using HPLC measurements, ketoprofen release studies were done at different pH conditions so as to mimick gastrointestinal fluids. The absence of release in acid conditions and a double phased release, at two different pH values (5 and 6.8), suggest that after activation these materials offer good potential for a modified release delivery system of ketoprofen.
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PMID:Synthetic zeolites as a new tool for drug delivery. 1808 45

To realize the simultaneous removal and recovery of phosphate and partial nitrogen from stale human urine, a series of lab-scale jar tests, adopting MgCl2 x 6H2O as precipitant, were conducted to study the influence of the molar ratio of Mg/PO4(3-)-P, pH, mixing speed, reaction time and precipitation time on MAP precipitation. The experiment results showed that the molar ratio of Mg/PO4(3-)-P was found to be a very important operating parameter to affect phosphorus recovery efficiency. When the molar ratio of Mg/PO4(3-)-P was above 1.3:1, the phosphorus recovery efficiency was above 95% and the residual phosphorous was less than 10 mg/L in the solution. Increasing pH with 10 mol/L NaOH solution could not increase the recovery phosphorus efficiency obviously. Without pH control, the optimal parameters of reaction time, precipitation time and mixing speed could be set at 20 min, 2.0 h and 120 r/min, respectively. To reveal the chemical characteristics of MAP products from human urine, three MAP product samples, with no pH adjustment and under the above optimal operation condition, were obtained at different Mg/PO4(3-)-P molar ratios of 1:1, 1.3:1 and 1.5:1, respectively, and analyzed with SEM, XRD and ICP instrumentation. These precipitates were identified as nearly pure struvite (12.62% of P, 5.71% of N and 9.91% of Mg) with the presence of trace calcium, potassium and sodium. The contents of phosphorus, nitrogen and magnesium in the precipitates were 13.54%, 5.34% and 9.01% (Mg/PO4(3-)-P = 1:1), 13.78%, 5.23% and 9.36% (Mg/PO4(3-)-P = 1.3:1), as well as 13.34%, 5.12% and 9.15% (Mg/PO4(3-)-P = 1.5:1), respectively.
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PMID:[Phosphorus removal and recovery from human urine with MAP crystallization]. 1826 83

The production of modest quantities of candidate bone lead (Pb) reference materials is described, and an optimized production procedure is presented. The reference materials were developed to enable an assessment of the interlaboratory agreement of laboratories measuring Pb in bone; method validation; and for calibration of solid sampling techniques such as laser ablation ICP-MS. Long bones obtained from Pb-dosed and undosed animals were selected to produce four different pools of a candidate powdered bone reference material. The Pb concentrations of these pools reflect both environmental and occupational exposure levels in humans. The animal bones were harvested post mortem, cleaned, defatted, and broken into pieces using the brittle fracture technique at liquid nitrogen temperature. The bone pieces were then ground in a knife mill to produce fragments of 2-mm size. These were further ground in an ultra-centrifugal mill, resulting in finely powdered bone material that was homogenized and then sampled-scooped into vials. Testing for contamination and homogeneity was performed via instrumental methods of analysis.
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PMID:Development of candidate reference materials for the measurement of lead in bone. 1842 43

The mechanism of La(3+) effect on chlorophyll (chl) of spinach in solution culture has been studied. The results show that La(3+) can obviously promote growth, increase chlorophyll contents and photosynthetic rate of spinach. La(3+) may substitute Mg(2+) for chlorophyll formation of spinach when there is no Mg(2+) in solution. La(3+) improves significantly PSII formation and enhances electron transport rate of PSII. By ICP-MS and atom absorption spectroscopy methods, it has been revealed that rare earth elements (REEs) can enter chloroplasts and increase Mg(2+)-chl contents; and REEs bind to chlorophyll and also form REE-chl. REE-chl is about 72% in total chlorophyll with La(3+) treatment and without Mg(2+)in solution. By UV-Vis, FT-IR and extended X-ray absorption fine structure spectroscopy (EXAFS) methods, it has been found that La(3+) coordinates with nitrogen of porphyrin rings with the average La-N bond length of 0.253 nm.
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PMID:Mechanism of lanthanum effect on chlorophyll of spinach. 1876 76

A poly(acrylamidrazone-hydrazide) chelating fiber has been synthesized from polyacrylonitrile fiber and used for enrichment-separation of traces of In(III), Sn(IV), Cr(III), VO(I) and Ti(IV) from solution samples with satisfactory results. These ions (5-250 ng/ml) can be quantitatively enriched (recovery > 95%) by the fiber at a 10 ml/min flow rate in the pH range 4-7, and desorbed quantitatively (recovery > 95%) with 10 ml of 2-5M hydrochloric acid from a fiber column at 6 ml/min flow rate. When the fiber, which had been stored in a glass bottle for about two years and then treated with strong acids (concentrated hydrochloric or nitric acid), was reused 10 times, the recoveries of the above ions by enrichment were still over 94%, and hundred-fold to thousand-fold excesses of Cu(II), Zn(II), Co(II), Ca(II), Mg(II), Fe(III) and Al(III) caused little interference in the determination of these ions by ICP-AES. The lowest concentrations for the proposed method were 50 ng/ml and In and Sn and 5 ng/ml for Cr, V and Ti. The RSD was 1.2-4.0%. The contents of these ions in real solution samples determined by this method were basically in agreement with the certified values of the samples, with average errors below 3.3%. The IR spectra of the fiber adsorbed with Cr(III) or VO(I) showed that Cr(III) or VO(I) combined mainly with nitrogen atoms in the fiber to form a coordination complex.
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PMID:Synthesis of poly(acrylamidrazone-hydrazide) chelating fiber and application of enrichment-separation for traces of indium, tin, chromium, vanadium and titanium from solution samples. 1896 61

In the present paper, the elemental composition of wood ashes obtained by the combustion of wood in a fireplace was determined with the use of ICP-MS and ICP-OES techniques. Wood ashes may find a potential application as deacidifying agents and soil conditioners, since they contain calcium (in the form of CaCO(3) and CaO), potassium (in the form of K(2)SO(4) and K(2)CO(3)) and significant levels of micronutrients. However, if applied to soil, it is important to assess the bioavailability of particular elements to plants. This process can be simulated by proper extraction procedures. Various species of wood were combusted in a firestove in a single-family house. The ashes underwent multielemental analyses with ICP-MS Varian Ultra Mass 700 (Australia) and ICP-OES Vista-MPX from Varian (Australia) in order to determine the content of macro- and micronutrients as well as toxic elements. Ashes were also extracted with solutions of 0.1M NaNO(3) and water in order to simulate the process of elemental transfer from ash (used as soil conditioner) to soil solution and consequently to plants. Also, the environmental impact of ash supplementation to soil was assessed in these experiments. Soil was supplemented with 0-20% of ash. After elution, the eluent underwent multielemental analysis by ICP-MS and ICP-OES techniques to determine the content of macronutrients (P, K, Mg), micronutrients (Fe, Mn, Co, Mo, Zn, Cu and Ti) and toxic elements (Hg, Pb, As and Cd). It was shown that fireplace ashes can be applied for deacidification of homestead gardens. Ash may be described as a valuable soil conditioner with N:P:K formula 0:1:3. It is concluded therefore that in order to achieve full fertilization, additional supplementation with nitrogen fertilizer would be necessary.
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PMID:The application of ICP-MS and ICP-OES in determination of micronutrients in wood ashes used as soil conditioners. 1897 Aug 65

Metal Fe or Cu doped P25 titania was prepared using the photodeposition method and characterized by TEM, ICP, XRD and UV-Vis, further tested for photocatalytic nitrate reduction and TN removal, under 20 W UV lamp irradiation. The influencing factors such as the pH values of solution, stirring gas, metal loadings, hole scavenger formic acid amount and co-doped Ag-Cu/TiO2 are investigated and discussed in detail. The experimental results after 2 h reaction indicated that with the increase of Cu loadings, nitrate conversion increases too, while a loading of 0.5% is optimal for highest N2 selectivity and TN (total nitrogen) removal. Using N2 as stirring gas and under acidic conditions, the N2 selectivity is lower (62%), but the highest conversion of nitrate and removal of TN can reach 36.9% and 23.2% respectively. Using CO2 as stirring gas, the highest selectivity for nitrogen 88.4% is obtained with 0.5% Cu/TiO2, 0.06 mol/L formic acid. Under the same conditions, using the prepared bimetallic titania (1%, 1:1 Ag/Cu), the conversion of nitrate and removal of TN are 48.1%, 34.2%, and N2 selectivity is 72.2%.
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PMID:[Photocatalytic reduction of nitrate using metal-doped titania]. 1906 39


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