نتایج جستجو برای: aqua regia extraction
تعداد نتایج: 170681 فیلتر نتایج به سال:
چکیده صنعت سیمان یکی از فعالیت های انسانی است که نقش تاثیر گذاری در شکوفایی اقتصادی دارد، اما در صورت مدیریت ناصحیح می تواند با ورود فلزات سنگین به محیط اطراف موجب آلودگی محیط زیست شود. در مطالعه حال حاضر برای تعیین غلظت فلزهای سنگین در خاک، از 45 نقطه اطراف کارخانه سیمان کردستان در شعاع های 500، 1000، 2000 و 3000 متری به صورت شعاعی و از عمق 15-0 و 30-15 سانتیمتری نمونه برداری شد. سپس مقادیر غ...
Using mesoporous SiO2 to encapsulate CsPbBr3 nanocrystals is one of the best strategies exploit such materials in devices. However, CsPbBr3/SiO2 composites produced so far do not exhibit strong photoluminescence emission and, simultaneously, high stability against heat and water. We demonstrate a molten-salts-based approach delivering CsPbBr3/mesoporous-SiO2 with PLQY (89 ± 10%) heat, water, aq...
A total of 32 samples of surficial soil were collected from 16 playground areas in Madrid (Spain), in order to investigate the importance of the geochemistry of the soil on subsequent bioaccessibility of trace elements. The in vitro bioaccessibility of As, Co, Cr, Cu, Ni, Pb and Zn was evaluated by means of two extraction processes that simulate the gastric environment and one that reproduces a...
A pilot study of metal content and basic soil properties was undertaken in a number of parks and allotments in the cities of Glasgow, UK, Torino, Italy, and Sevilla, Spain. Between 40 and 60 samples were collected from each city, with soil from two depths. The maximum metal contents (aqua regia) found were 698 mg/kg Cu; 1004 mg/kg Zn; 300 mg/kg Ni; 356 mg/kg Cr and 7051 mg/kg Pb. Variability of...
It is generally supposed that the preconcentration procedure is used for the determination of metal concentrations under the sensitivity of the measurement method. This study showed that preconcentration is also need for the beryllium (Be) concentration over the sensitivity of atomic absorption spectrometry. For this purpose, a simple and selective method for the determination of Be in solid sa...
The amount of protein wasted through sludge in Gauteng, South Africa, amounts to 95 000 metric tonne/yr, with the order of magnitude of the national protein requirement of approximately 145 000 metric tonne/yr. Waste-activated sludge (WAS) from wastewater treatment plants (WWTPs) that treat domestic wastewater contains protein in a ratio of 2:1 against fishmeal. This protein source has not been...
Determination of the true surface areas, concentrations, and particle sizes of gold nanoparticles (AuNPs) is a challenging issue due to the nanoparticle morphological irregularity, surface roughness, and size distributions. A ligand adsorption-based technique for determining AuNP surface areas in solution is reported. Using a water-soluble, stable, and highly UV-vis active organothiol, 2-mercap...
An enzyme glucose microsensor using a glucose oxidase-immobilized porous carbon/Teflon composite microelectrode was developed. The microsensor was fabricated by etching a platinum microelectrode (platinum, radius of 25 and 50 micrometers) in hot aqua regia to create a cavity at the tip and then packing a porous carbon/Teflon composite, which was made from acetylene black and Teflon emulsion, in...
Recent years have witnessed intensification of road traffic and, with it, the amount of substances emitted by vehicles. Such emissions need to be monitored for public health purposes. The aim of this study was to evaluate the impact of the highway traffic on the total content and bioavailability of Zn, Cu, Ni, Cd, Cr and Pb in nearby soils as well as influence of an acoustic screen on spatial d...
three samples were collected over an eight hour period on August 25, 2005 and combined into one composite sample. Raw green liquor was a two-sample composite because of a change that occurred in recovery boiler operation. Lime rock was a composite sample collected May 19, 2005. Pulp production on August 25, 2005 was 565 ADT. Results are given in Tables I and II. Samples for the mill trial were ...
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