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81.
Patrick J. Gray Sean D. Conklin Todor I. Todorov Sasha M. Kasko 《Food additives & contaminants. Part A, Chemistry, analysis, control, exposure & risk assessment》2016,33(1):78-85
This paper reports the effects of rinsing rice and cooking it in variable amounts of water on total arsenic, inorganic arsenic, iron, cadmium, manganese, folate, thiamin and niacin in the cooked grain. We prepared multiple rice varietals both rinsed and unrinsed and with varying amounts of cooking water. Rinsing rice before cooking has a minimal effect on the arsenic (As) content of the cooked grain, but washes enriched iron, folate, thiamin and niacin from polished and parboiled rice. Cooking rice in excess water efficiently reduces the amount of As in the cooked grain. Excess water cooking reduces average inorganic As by 40% from long grain polished, 60% from parboiled and 50% from brown rice. Iron, folate, niacin and thiamin are reduced by 50–70% for enriched polished and parboiled rice, but significantly less so for brown rice, which is not enriched. 相似文献
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In this study, 2,4-DNPH coated magnetite was used for removal of As(V) and V(V) ions from aqueous solution. The synthesized nanoparticles were characterized by XRD analysis, FT-IR, SEM, and SEM-EDXS measurement. The size of the nanoparticles according to SEM was obtained as around 20–35 nm. Equilibrium isotherm data showed that the Langmuir–Freundlich model was in a good agreement with the experimental data according to high correlation coefficient. The maximum adsorption capacities of As(V) and V(V) on adsorbent were 338.4 and 266.8 mg g?1, respectively. Kinetic study showed that the fractal like-PSO model was appropriate to describe the adsorption process. The optimum pH was obtained to be 7 and 5 for As(V) and V(V) ions, respectively. 相似文献
87.
Mirna E. Sigrist Horacio R. Beldomenico Enrique E. Tarifa Carlos L. Pieck Carlos R. Vera 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2011,86(10):1256-1264
BACKGROUND: Arsenic decontamination of drinking water by adsorption is a simple and robust operation. When designing packed bed adsorbers for arsenic, the main problems are the slow diffusion kinetics of As in microporous media and the lack of simple equations for predicting the performance of the equipment. Commercial iron‐doped granular activated carbon adsorbents (Fe/GAC) for groundwater arsenic abatement were studied in this work. Basic parameters for arsenate (AsV) adsorption were measured and their performance at larger scale was simulated with an approximate analytical model. RESULTS: In the 0–300 µgAs L?1 range, the AsV adsorption isotherm on Fe/GAC was found to be approximately linear. Assuming Henry's law for adsorption and homogeneous surface diffusion with constant diffusivity for intrapellet mass transfer, an approximate model for flow and adsorption of arsenate inside packed bed adsorbers was developed, and reduced to an analytic compact solution using the quasi‐lognormal distribution (Q‐LND) approximation. The use of this model with fitted and reported parameters enabled the approximate simulation of industrial adsorbers and home point‐of‐use filters. Results show that industrial adsorbers meet the breakthrough condition with incomplete utilization of the adsorbent unless convenient process configurations are used. In point‐of‐use systems with short residence times intraparticle diffusion would drastically reduce the adsorbent performance. CONCLUSION: Assuming linear adsorption of AsV over Fe/GAC, an analytical approximate solution for flow and adsorption in packed beds can be obtained. The model seems to represent correctly the main features of industrial and home filters, however, more experimental data is necessary for scale‐up purposes. Copyright © 2011 Society of Chemical Industry 相似文献
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《中国有色金属学会会刊》2019,29(10):2213-2221
The selective removal of arsenic from arsenic-bearing dust containing Pb and Sb in alkaline solution was studied. The influence of NaOH concentration, temperature, leaching time, liquid to solid ratio, and the presence of elemental sulfur on the dissolution of As, Sb and Pb in NaOH solution was investigated. The results indicate that the presence of elemental sulfur can effectively prevent leaching of lead and antimony from arsenic. The Sb2O3, As2O3 and Pb5(AsO4)3OH in the raw material convert to NaSb(OH)6 and PbS in the leaching residue, while arsenic is leached out as As(III) or As(V) ions in the leaching solution. Arsenic leaching efficiency of 99.84% can be achieved under the optimized conditions, while 97.82% of Sb and 99.97% of Pb remain in the leach residue with the arsenic concentration of less than 0.1%. A novel route is presented for the selective removal of arsenic and potential recycle of lead and antimony from the arsenic-bearing dust leached by NaOH solutions with the addition of elemental sulfur. 相似文献
90.
煤矿开采沉陷移动变形预测 总被引:1,自引:0,他引:1
为了预测评价开采沉陷对矿区环境的影响,正确选择环境保护措施,必须对开采沉陷引起的地表下沉、倾斜、曲率、水平变形等移动变形值、地表移动持续的时间和最大下沉速度、开采沉陷的范围、冒落带和导水裂隙带的高度以及采动过程中地表移动变形等进行预测,本文将介绍几种预测方法. 相似文献