عنوان مقاله
گوگرد زدایی زیستی زغال سنگ با Acidithiobacillus caldus و تحلیل اثرات متقابل سطحی بین سلول ها و پیریت
فهرست مطالب
چکیده
مقدمه
مواد و روش ها
نتایج و بحث
نتیجه گیری
بخشی از مقاله
آزمایش گوگرد زدایی زیستی ذغال سنگ
فرایند های گوگرد زدایی زیستی در فلاسک هایی با ظرفیت حجمی 100 میلی لیتر در 250 میلی لیتر محیط اب نمک بازی، 10 درصد w/v تراکم خمیر،اندازه ذرات 65- تایلر مش،غلظت اولیه سلول 1.0×106 بر میلی لیتر ،زمان فراوری 30 روز انجام شد. هر 4 روز یک بار مقادیر اسید و غلظت اهن سیستم گوگرد زدایی زیستی تعیین شد. در انتهای ازمایش گونه های ذغال سنگ تهیه شده سپس گوگرد کل و مقدار نسبی گوگرد در نمونه های ذغال سنگ اندازه گیری شد.
کلمات کلیدی:
Biodesulfurization of coal with Acidithiobacillus caldus and analysis of the interfacial interaction between cells and pyrite Huan He a, ⁎, Fen-Fen Hong a , Xiu-Xiang Tao a, ⁎, Lei Li a , Chen-Yan Ma b , Yi-Dong Zhao b a Key Laboratory of Coal Processing and Efficient Utilization of Ministry of Education, School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou, 221116, China b Beijing Synchrotron Radiation Facility, Institute of High Energy Physics, Chinese Academy of Science, Beijing, 100049, China article info abstract Article history: Received 13 August 2011 Received in revised form 28 March 2012 Accepted 7 April 2012 Available online xxxx Keywords: Biodesulfurization Acidithiobacillus caldus Interfacial interaction Sulfur speciation XANES In the present work, the acidophilic and thermophilic strain Acidithiobacillus caldus was used for biodesulfurizing coal and bioleaching coal pyrite. The surface characteristics of cells and minerals and the mineral transformation during the coal pyrite leaching process were investigated combined with zeta-potential, FT-IR spectroscopy, scan electronic microscopy and X-ray absorption near edge structure spectroscopy (XANES). The results showed that the coal pyritic desulfurization with A. caldus was about 47% and the total desulfurization was 19%. After processed by cells, there was clear corrosion on the pyrite surface. Coal pyrite and elemental sulfur-grown cells had more hydrophilic functional groups than thiosulfate-grown cells. During the coal pyrite leaching course, the elemental sulfur was the main sulfur speciation but no other secondary mineral components were detected. © 2012 Elsevier B.V. All rights reserved. 1. 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 [12–14]. 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].
