دانلود مقاله ترجمه شده گوگرد زدایی زیستی زغال سنگ و آنالیز اثرات متقابل سطحی – مجله الزویر

فهرست مطالب:

چکیده
۱مقدمه
۲ مواد و روش ها
۲ ۱ نمونه ی ذغال سنگ و شرایط کشت سویه های باکتریایی
۲ ۲ ازمایش گوگرد زدایی زیستی ذغال سنگ
۲ ۳ ازمایش فرو شویی زیستی پیریت
۲ ۴ تجزیه تحلیل نمونه
۳ نتایج و بحث
۳ ۱ فرایند گوگرد زدایی زیستی زغال سنگ
۳ ۲عملکرد فروشویی زیستی پیریت A caldus
۳ ۳ تجزیه تحلیل پیریت توسط میکروسکوپ الکترونی نگاره
۳ ۴ خصوصیات سطحی سلول ها و پیریت
۳ ۵ تجزیه تحلیل فروشویی زیستی پیریت و گونه زایی گوگرد
۴ نتیجه گیری

بخشی از ترجمه:

 سویه اسید دوست و گرما دوست A. caldus نخست برای گوگرد زدایی زیستی زغال سنگ استفاده شد . نتایج نهایی حاکی از گوگرد زدایی زیستی پیریت و گوکرد زدایی زیستی کل به ترتیب ۴۷ و ۱۹ درصد بود. بعد از فراوری به مدت ۴۰ روز، سلول به سطح پیریت هاچسبیده و هیچ گونه خوردگی روی سطح کانی وجود نداشت. به علاوه، سلول های رشد یافته سوبستراهای مختلف گوگرد، خصوصیات سطحی متفاوتی رانشان داد ند. بر عکس، سلول های رشد یافته روی پیریت و گوگرد عنصری دارای گروه های عاملی اب دوست تر از تیوسولفات بودند.
گوگرد عنصری یک عنصر و مولفه مهم گوگردی در فروشویی زیستی زغال سنگ می باشد با این حال هیچ گونه ترکیب معدنی ثانویه شناسایی نشد.

بخشی از مقاله انگلیسی:

Introduction Coal is the most abundant fossil fuel in the world. However, the combustion of coal containing high sulfur causes serious environmental damage such as acid rain because of emission of sulfur dioxide [1]. Sulfur is present in coal mainly in three forms: pyritic, organic and sulfate sulfur. The organic sulfur is the integral part of the coal matrix, whereas pyritic sulfur is present in coal as mineral matter. There are several physical–chemical methods employed to eliminate the organic or inorganic sulfur fractions of coal by floatation, oxidation and reduction with chemicals [2]. Nevertheless, these physical methods cannot remove the pyrite when these sulfides are finely dispersed in coal matrix. Furthermore, although the chemical methods can remove organic and inorganic sulfur from coal, which will also produce hazardous secondary products and lead to loss of partial combustible matter [3,4]. Biodesulfurization offers a clean alternative method to remove sulfur from coals, in which the microbes can catalyze the biochemical reaction in an aqueous medium resulting in the oxidation and dissolving of the sulfur content into sulfate [4,5]. Among of them, the mesophillic microbes, mainly A. ferrooxidans and A. thiooxidans have been frequently applied to remove the pyrite from coals [4,6,7]. However, in the last decade, limited literatures reported that the thermophilic microbes were used to eliminate the sulfur from coal [8,9]. Recently, A. caldus has been reported as the dominant sulfur-oxidizing thermophilic bacterium accounting for the relatively high percentage in bioleaching pyrite at 45 °C [10,11]. To our knowledge, it has never been used in coal’s biodesulfurization process. It is well known that the attachment of cells on the surface of mineral is reported to be involved in the oxidation of sulfide minerals, which depends not only on the interfacial process between the cells and mineral surface but also the biochemical properties of the cells. Furthermore, it has been reported that the surface properties of bacterial cells are significantly influenced by the growth conditions [12–۱۴]. Hence, a better understanding of the surface properties of functional bacteria under different conditions is helpful to illustrate the interfacial interaction between cells and mineral surface [15,16]. The bio-oxidation of pyrite has been widely investigated and a possible mechanism has been proposed: the stepwise oxidation and the formation of surface-bound thiosulfate, and then oxidized via tetrathionate and other polythionates, finally to sulfate [17–۱۹]. Many investigators agreed that the precipitation of mineral phases during the pyrite oxidation process may affect the efficiency of sulfur removal [20,21]. Besides the reported jarosite, the sulfur-rich layers may also deposit onto the surface of pyrite, thus preventing the contact of the microorganisms and hindering the leaching process [21–۲۳]. The object of this study is to investigate the coal’s biodesulfurization and the coal pyrite’s bioleaching by thermophilies A. caldus cells and the interfacial interaction between cells and coal pyrite surface with the approaches of zeta-potential, FT-IR spectroscopy, SEM and sulfur Kedge XANES. ۲٫ Material and method 2.1. Coal sample and bacterial strains’ culture conditions The coal sample used in the experiment was collected from Indonesia area named MTWL-7 and the total sulfur of it was 2.15%, which was sterilized at 120 °C for 20 min. The pyrite powders used in the experiments were picked up from the coal samples and the component was analyzed with XRD (data not shown). A. caldus derived from the acid hot spring of Yun-nan province, south east of China was cultivated in the Starkey basal salt medium [24] supplemented with sulfur powder, pyrite, coal and thiosualfate, and the initial pH of culture were 2.5, 2.5, 2.5 and 4.8, respectively. The culture of A. caldus was grown in 250 mL flasks containing 100 mL medium and incubated at 40 °C with 170 rpm shaking. Bacterial cells were cultured until late exponential phase and harvested by the following procedure: the cultures were filtered three times through filter paper (pore size 7–۱۰ μm) to remove the suspended solid particles and then the filtrates were centrifuged at 10,000 rpm for 15 min, and the cell pellets were washed thrice in diluted sulfuric acid (0.1 mol.L−۱ ) in order to remove any trapped ions, finally all the samples were freezedried and stored at −۲۰ °C for zeta-potentials and the FT-IR test. 2.2. Coal biodesulfurization experiment The biodesulfurization processes were carried out in flasks with a volume capacity of 100 mL in 250 mL of basic salt medium, 10% w/v pulp density, particle size of −۶۵ Tyler mesh, the initial cell concentration was 1.0 × ۱۰۶ cells.mL−۱ , processing time of 30 d. Every four days, the pH values, and concentration of iron of biodesulfurization system were determined. At the end of the experiments, the coal samples were prepared with the method mentioned in the literature [25], then the total sulfur and the relative sulfur contents in the coal samples were measured [26].

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