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Thermodynamic Modeling of Uranium (VI) Reductive Immobilization in Groundwater of NPCC Sludge Storages (Novosibirsk, Russia)

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Journal of Geoscience and Environment Protection 2018年第11期6卷 181-189页

作者： Olga L. Gaskova A. E. Boguslavsky A. V. Safonov Sobolev Institute of Geology and Mineralogy SB RAS Novosibirsk Russia Novosibirsk State University Novosibirsk Russia Frumkin Institute of Physical Chemistry and Electrochemistry Russian Academy of Sciences (IPCE RAS) Moscow Russia

The Biochemical Reduction Of Both Nitrate And Sulfate In U-Containing Aquifers Of The Novosibirsk Plant Of Chemical Concentrates (NPCC) Was Investigated Experimentally And Thermodynamically. It Was Observed That Decrease In Eh Up To -397 Mv Has A Distinct Effect On The Denitrification And Uranium Precipitation As UO2(S). Nitrate Was Denitrified With A Temporary Accumulation Of The Intermediate Nitrite On The Day 4th. According To The X-Ray Fluorescence Analysis And Thermodynamic Calculations, More Than Half Of The Uranium Is Deposited In The First Stage As UO2+X oxides, And The Rest, Together With The Sulfides In The Reducing Environment. Findings Suggest That Accurately Thermodynamic Predicting Of Groundwater NO3-;?And SO42- Fate Is Primarily Limited By Failing To Account For A Kinetic Of Redox Fluctuations In The Experiment: 1) Measured Eh +190 Mv Is Low Despite The High Amount Of Nitrates (1124 Mg/L), But NH4+ Predominates In Solution According To Calculations, 2) Sulfate Reduction Lagged Behind Nitrate Reduction By Approximately 50 Days Unlike Model Simulation.

关键词： Uranium wastes Bacterialreduction Nitrogen Sulfur Thermodynamic Model

Suppression of Pyrite Oxidation by Surface Silica Coating

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Journal of Geoscience and Environment Protection 2014年第4期2卷 37-43页

作者： K. Kollias E. Mylona K. Adam N. Papassiopi N. Papassiopi A. Xenidis School of Mining and Metallurgical Engineering National Technical University of Athens Athens Greece

The exposure of pyrite (FeS2) to atmospheric conditions during mining activity causes a series of complex oxidation reactions, resulting to acid generation and the subsequent release of toxic heavy metals in the surrounding aquatic and terrestrial ecosystems. The produced acidic mine waters, known as acid mine drainage (AMD), constitute one the major environmental problems of both operating and abandoned mixed sulphide, coal and other mine sites where sulphidic minerals are encountered. A sustainable approach to the environmentally safe pyrite-bearing extractive waste management is related to the prevention of oxidation by developing artificial coatings on the pyrite surfaces. In this study, experiments performed to study the conditions of the silica coating formation on the FeS2 particles contained in a pyrite concentrate are presented. Batch tests involving the treatment of pyrite samples with a coating solution, consisting of Na2SiO3, H2O2 and buffered pH, were performed under a liquid to solid ratio (L/S) 100 l/kg. The effect of parameters including SiO2 concentration (5 - 50 mM), pH values (5.0 - 8.0) and contact time up to 24 hours, was investigated. Parameters examined to monitor the silica coating formation process include analysis of Fe, Si, ?and H2O2 in the aqueous phase. Scanning electron microscopy with energy dispersive spectrometry (SEM/EDS) was used for the examination of the chemically modified surfaces of silica-treated pyrite samples.

关键词： Acid Mine Drainage Mine wastes Pyrite Silica Coating

Conference Paper: Green Industry Adapted to Recycling Needs of Lubumbashi City and Surrounding Areas in Democratic Republic of the Congo

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Green and Sustainable Chemistry 2019年第1期9卷 11-25页

作者： Topwe Milongwe Mwene-Mbeja Department of Chemistry Faculty of Science University of Lubumbashi Lubumbashi Democratic Republic of the Congo

The interest of this conference is agricultural, environmental, bioenergetics, and sanitary. In that context, domestic, agricultural and industrial environments produce organic waste, which needs to be collected, selected, stored and recycled properly in order to avoid environmental pollution and promote agriculture. The green Industry proposed involves the conversion of natural, non-toxic organic waste in order to efficiently produce organic fertilizers for agriculture. These types of fertilizers from biological origin are suitable because they are not toxic for human and the environment. Enzymatic reactions described in this presentation concern mainly the hydrolysis of proteins, sugars and lipids, the acidification of intermediate products from hydrolysis, the formation of acetate, and the production of methane. In other words, this review is timely as it discusses for the chemical behavior or the reactivity of different functional groups to better understand the enzymatic catalysis in the transformations of residual proteins, carbohydrates, and lipids to generate biomethane and fertilizers. In the same perspective, this review is to enrich the documentation related to organic reactions catalyzed by enzymes, which occur in the anaerobic degradation of residual organic substances, with emphasis on the structures of organic compounds and reaction mechanisms. This will allow understanding the displacement of the electrons of a reactive entity rich in electrons to another reactive entity that is poor in electrons to form new bonds in products.

关键词： Organic wastes Organic Fertilizers Bioenergetics Pollution Environment Biocatalysts

Relationship between Chemical Durability, Structure and the Ionic-Covalent Character of Me-O-P Bond (Me = Cr, Fe), in the Vitreous Part of the System 60P2O5-2Cr2O3-(38 - x) Na2O-xFe2O3(with 3 ≤ x ≤ 33 mol%)

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Advances in Materials Physics and Chemistry 2019年第10期9卷 199-209页

作者： Nadia Beloued Radouane Makhlouk Yassine Er-Rouissi M’hammed Taibi Mohammed Sajieddine Said Aqdim Laboratory of Materials Engineering for Environment and Valorization Faculty of SciencesHassan II University Ain ChockCasablancaMorocco Physico-Chemistry Laboratory of Inorganic and Organic Materials ENS University Md VRabatMorocco Physics and Mechanics of Materials Laboratory Faculty of Sciences and TechnicalSultan Moulay Slimane UniversityBeni MellalMorocco Mineral Chemistry Laboratory Department of ChemistryFaculty of ScienceHassan II University Ain ChockCasablancaMorocco

The structure and chemical durability in the vitreous part of the system 60P2O5-2Cr2O3-xFe2O3-(38 - x)Na2O phosphate glasses (with 3 ≤ x ≤ 33 mol%) were investigated using various techniques such as IR spectroscopy, X-ray diffraction and M?ssbauer spectroscopy. The presence of Cr2O3 and the increase of Fe2O3 at the expense of Na2O in the glass network lead to a large number of covalent and rigid Fe-O-P and Cr-O-P bonds. The infrared and XRD spectra indicate a radical change of structure and show that the increase of the Fe2O3 content favors the depolymerization of the vitreous network towards pyrophosphate chains. The presence of Cr2O3 in the glass seems to favor the covalent Cr-O-P bonds linked to the most probable cyclic metaphosphate chains. However, when the Fe2O3 content increases (≥23 mol%), its impact on the glass network is stronger than that of Cr2O3. The infrared and XRD spectra indicate a radical change of structure and show that the increase in Fe2O3 content favors the depolymerization of the vitreous network to short pyrophosphate chains. The results of M?ssbauer spectroscopy indicate the presence of both Fe (III) and Fe (II) ions which occupied more or less deformed octahedral sites. The growth of the glass transition temperature (Tg) with the increase of the iron oxide in the vitreous network, leads to an improvement of the glass rigidity. This explains the decrease of the ionic radius of the iron and the reinforcement of the interconnection of the chains of vitreous networks. The structure of sodium-chromium-iron phosphate glasses can be considered largely as pyrophosphate units linked to ferric and ferrous ions in octahedral or deformed octahedral coordination. The dissolution rate is 200 times lower than that of the silicate glasses.

关键词： Chemical Durability Phosphate Glasses Chromium and Iron Oxides IR XRD Nuclear and Chemical wastes

Understanding Accelerator Driven System (ADS) Based Green Nuclear Energy: A Review

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World Journal of Nuclear Science and Technology 2015年第4期5卷 287-302页

作者： Mohammad Kamal Hossain Md. Abu Taher Mithun Kumar Das Department of Physics Comilla University Comilla Bangladesh

This paper reflects the scopes of accelerator driven system (ADS) based nuclear energy, as a reliable source of electric energy generation, comparing to the other existing non-renewable and renewable sources. There are different limitations in the use of every source of electric energy but in consideration of minimum environmental impact, exclusively inherently low greenhouse gas (GHG) emission, and also, high life time with maximum power production efficiency, nuclear would be the best choice. From this study it was found that several difficulties involved in the ADS based energy production, more specifically, difficulties regarding the target parameters, coding system, waste management, etc. Hence suggestions from this study points out that if it is possible to ensure more energy efficient production of enriched uranium, improved nuclear fuels and reactors that allow greater utilization, extended life times for nuclear power plants (NPPs) that reduce the need to build new facilities, improved coding system capable of minimizing the discrepancy between theoretical and experimental calculation of spallation products, improved data library with sufficiently available high energy nuclear data to perform a better coding analysis, and finally, considering the environmental safety if the disposal of the radioactive wastes could manage more effectively, nuclear energy would then play a significant role in minimizing future energy crisis worldwide as well as to save our loving green earth.

关键词： Green Nuclear Energy Spallation Accelerator Driven System Transmutation of wastes Sustainable Energy Development

Assessment of the Integrity and Retention of Chromium (VI) in Portland Cement Pastes

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Advances in Chemical Engineering and Science 2021年第1期11卷 1-17页

作者： Ferreira Raul Tadeu Lobato Fortaleza Dário Batista Amorim Kelly Aparecida da Encarnação Lira Fernanda Silva Silva Marizete Helena Pereira Wagner Batista Santos Institute of Exact Sciences and Earth Federal University of Mato Grosso Barra do Gar&#231as/MT Brazil

Chromium is a heavy metal used for various applications such as in the manufacture of stainless steels, in chemicals for wood treatment, in tanneries, and in the refractory industry. The main problem associated with the use of chromium in these activities is the considerable volume of contaminated effluent that requires treatment, mainly due to its high mobility and toxicity in its hexavalent form. Immobilization methods arise as an efficient solution for the treatment of these wastes through converting them into inert and stable materials. The present paper aims to investigate Portland cement II’s paste properties with potassium dichromate addition in order to verify the chromium immobilization process. Analyses of moisture content, water absorption, axial compressive strength, and solubilization were done in samples at 7 and 28 days with 0%;0.5%;1.05;1.5%;2.0% and 2.5% potassium dichromate addition. The results showed the influence of this salt in cement hydration reactions, damaging the mechanical behavior and the water absorption capability of the material produced. In the solubilization test, all compositions had >99% efficiency of chromium immobilization in both ages of hydration, thus demonstrating the capability of a cementitious matrix to stabilize this metal.

关键词： wastes Solidification-Stabilization Chromium Solubilization

Method of Biological Wastewater Final Treatment Using Bioremediation in Northern Khabarovskiy Krai

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Method of Biological Wastewater Final Treatment Using Biorem...

Assessment of Ornamental Stone Waste as Expansive Soil Stabilizer

2014 International Conference on Green Materials and Environmental Engineering (GMEE2014)

作者： Konstantin Gula Liudmila Krupskaya Eugene Shevkun Valentina Zvereva Pacific National University Far East Federal University Far East Geological Institute FEB RAS

The article presents the results of experimental research for final treatment of gold mining enterprise waste waters using water lentil（Lemna minor） of（Lemna L.） genus,（Lemnactat S.F. Gray） family, and common red grass（Phrágmites austrális（Cav.） Trin. Ex Steud.）. It was shown that a level of heavy metals extraction, cyanides and rhodanides from the industrial waters of gold processing plant is greatly higher in comparison with chemical method used at the plant. The proposals are given to the gold mining enterprise to establish a pilot plant for final biological treatment, its novelty is confirmed by the Patent of Russian Federation of 20.01.2014.

关键词： Treatment Waste waters Pollutants Bioremediation wastes

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矿物学报 2013年第S1期33卷 2-2页

作者： Abdel Monem M Soltan.Waleed A.Ogila Geology Department Faculty of ScienceAins Shams UniversityCairo-11566Egypt

This work aims to assessment of the calcitic ornamental stone waste for the stabilization of expansive soil. Calcitic rock-derived waste together with different expansive soils from Egypt were characterized and processed for stabilizer optimization. The mineral, chemical and engineering characteristics of the waste and the soil samples were examined using XRD, DTA, TGA, SEM, XRF as well as geotechnical characteristics such as liquid, plastic and shrinkage limits, plasticity index, free swelling, and uni-axial compressive strength, respectively. The calcitic waste has been calcined in an electrical muffle furnace at 1000℃ for 1 hour. The samples were treated by 0–8% waste post calcination for soaking time1– 4 weeks.

关键词： calcitic wastes expansive soil stabilization.