دانلود مقاله ترجمه شده جاذب ارزان قیمت برای حذف آلاینده های آلی از پسماند فاضلاب – مجله الزویر

فهرست مطالب:

چکیده
۱ مقدمه
۲ توسعه و ایجاد جاذب های ارزان قیمت
۲ ۱ انتخاب پیش ماده
۲ ۲ انواع پیش ماده ها
۲ ۳ روش فراوری
۳ کربونیزاسیون و اکتیواسیون
۴ کابرد های پسماند های ارزان قیمت
۴ ۱ پسماند های خانگی
۴ ۱ ۱ پسماند های میوه
۴ ۱ ۲ پوست نارگیل
۴ ۱ ۳ پسماند های لاستیکی
۴ ۲ فراورده های کشاورزی
۴ ۲ ۱ پوست درخت و دیکر مواد غنی از تانن
۴ ۲ ۲ خاک اره و دیکر مواد چوبی
۴ ۲ ۳ شلتوک برنج
۴ ۲ ۴ دیگر پسماند های کشاورزی
۴ ۳ پسماند های صنعتی
۴ ۳ ۱ پسماند هدی نفت
۴ ۳ ۲پسماند کودی
۴ ۳ ۳ خاکستر
۴ ۳ ۴ پسماند های کارخانه قند
۴ ۳ ۵ پسماند کوره های فولادی
۴ ۴ مواد دریایی
۴ ۴ ۱ چیتوزان و پسماند های فراوری غذاهای دریایی
۴ ۴ ۲ گیاهان دریایی و جلبک
۴ ۴ ۳ پیت ماس
۴ ۵ خاک و مواد کانسنگی
۴ ۵ ۱ رس ها
۴ ۵ ۲ گل قرمز
۴ ۵ ۳ زئولیت ها
۴ ۵ ۴ رسوب و خاک
۴ ۵ ۵ کانی های کانسنگی
۴ ۶ هیدروکسید ها و اکسید های فلزی
۴ ۷ پسماند های متنوع
۵ مکانیسم جذب
۶ زمینه های مطالعاتی آینده
۷ نتیجه گیری

بخشی از ترجمه:

آلودگی آب ناشی از آلاینده های آلی به دلیل وجود سمیت حاد و ماهیت سرطان زایی آلاینده ها یک مشکل جدی مطرح می باشد. در میان روش های مختلف تصفیه آب، فرایند جذب سطحی به عنوان بهترین روش مطرح است زیرا ارزان، دارای ماهیت جهانی و سهولت استفاده می باشد. بسیاری از مواد پسماند مورد استفاده شامل پسماند های میوه، پوست نارگیل، پوست درخت، لاستیک های حاصل از فراوری گیاهان، مواد غنی از تانن، خاک اره و دیکر مواد چوبی، شلتوک برنج، پسماند های کودی، خاکستر، پسماند هی کوره کارخانه قند، پسماند های فراوری چیتوزان و غذاهای دریایی، گیاهان دریایی و جلبک ها، پیت ماس، رس ها، گل قرمز، زئولیت ها، رسوب و خاک، کانی های کانسنگ و غیره می باشند. این جاذب ها می توانند طیف وسیعی از آلاینده های بالقوه را متغیر از ۸۰ تا ۹۹.۹ درصد را حذف کنند. مقاله حال حاضر به توصیف تبدیل فراروده های پسماند به جاذ ب های موثر و کارامد و کاربرد آن ها رد تصفیه پسماند می پردازد.مکانیسم احتمالی جذب سطحی این جاذب ها روی این جاذب هانیز در این مقاله گنجانده اند. به علاوه، تلاش هایی در خصوص چشم اندازها و ابعاد آینده جاذب های ارزان قیمت در تصفیه آب مورد بحث قرار گرفته اند.

۱ مقدمه

یکی از مهمترین ملزومات آب در حال حاضر، بهبود کیفیت و حفظ مداوم آن می باشد. با این حال منابع آلاینده نقطه ای و غیر نقطه ای در حال آلوده کردن منابع ارزشمند آبی ما می باشند.کیفیت منابع آبی ما به دلیل افزایش مداوم مواد شیمایی نامطلوب به آن ها روز به روز در حال تنزل می باشد(لوویچ ۱۹۷۹).منابع اصلی آلودگی آب شامل صنعتی شدن، توسعه شهرنشینی، فعالیت های کشاورزی و دیکر تغییرات جهانی و زیست محیطی میباشند. تاکنون ، چند صد آلاینده ارگانیک یافت شده اند که موجب آلودگی آب می شوند.آلودگی ناشی از آلاینده های آلی و ارگانیک به دلیل اثرات جانبی متعدد آن ها و ماهیت سرطان زایی خود بسیار خطرناک می باشند.(یانگ ۲۰۱۱). از این رو، اهمیت بهبود و حفاظت منابع آبی بسیار ضروری بوده و از اهمیت روز افزون برخوردار است. دانشمندان، نخبگان دانشگاهی و آژانس های دولتی در زمینه های آلودگی منابع آبی در سراسر جهان بسیار جدی بوده و اتفاق نظر دارند. آب های سطحی وزیرزمینی در بسیاری از نقاط جهان آلوده می شوند وبرای اهداف آشامیدنی مناسب نمی باشند. تا سال ۲۰۵۰، انتظار می رود جمعیت جهان تا بیش از ۹.۳ میلیارد افزایش پیدا کند( گزارش سازمان ملل ۲۰۱۱) و جهت ممکن است تحت محدودیت بیشتر آب شیرین قرار گیرد. از این رو، حذف آلاینده های سمی ارگانیک از آب ذر سناریوی فعلی بسیار ضروری می باشد.

بخشی از مقاله انگلیسی:

Water pollution due to organic contaminants is a serious issue because of acute toxicities and carcinogenic nature of the pollutants. Among various water treatment methods, adsorption is supposed as the best one due to its inexpensiveness, universal nature and ease of operation. Many waste materials used include fruit wastes, coconut shell, scrap tyres, bark and other tannin-rich materials, sawdust and other wood type materials, rice husk, petroleum wastes, fertilizer wastes, fly ash, sugar industry wastes blast furnace slag, chitosan and seafood processing wastes, seaweed and algae, peat moss, clays, red mud, zeolites, sediment and soil, ore minerals etc. These adsorbents have been found to remove various organic pollutants ranging from 80 to 99.9%. The present article describes the conversion of waste products into effective adsorbents and their application for water treatment. The possible mechanism of adsorption on these adsorbents has also been included in this article. Besides, attempts have been made to discuss the future perspectives of low cost adsorbents in water treatment.
۲۰۱۲ Elsevier Ltd. All rights reserved. 1. Introduction Being the utmost importance of water the need of its quality improvement and preservation growing continuously. But the point and non-point sources are contaminating our valuable water resources. The quality of our water resources is deteriorating day by day due to the continuous addition of undesirable chemicals in them (Lvovich, 1979). The main sources of water contamination are industrialization, civilization, agricultural activities and other environmental and global changes. Few hundred organic pollutants have been found contaminating water resources. The contamination due to organic pollutants is very dangerous due to their various side effects and carcinogenic nature (Yang, 2011). Therefore, the importance of water quality preservation and improvement is essential in life and increasing continuously. The scientists, academicians and governmental agencies are very serious on the pollution of water resources globally. The surface and ground waters at many places of the world are contaminated and not fit for drinking purpose. By 2050, the global population is expected to reach up to 9.3 billion (United Nations, 2011) and the world may be under great fresh water scarcity. Therefore, the removal of toxic organic pollutants from water is essential in the present scenario. Literature reports some methods for the removal of organic pollutants from water (Aboul-Kassim and Bernd, 2001; Ali, in press; Bansal and Goyal, 2005; Boyd et al., 1947; Cheremisinoff and Ellerbusch, 1979; Coin et al., 1996; Faust and Aly, 1983, 1987; Koros, 1995; Lin and Chen, 1997; Mattson and Mark, 1971; McNulty, 1984; Mota and Lyubchik, 2006; Nemerow and Dasgupta, 1991; Reichenberg, 1953; Ruthven, 1984; Samuel and Osman, 1987; Weber and Holz, 1991; Williams, 1991; Zinkus et al., 1998; Zor et al., 1998). The basic principle of these methods depends on their physical, chemical, electrical, thermal and biological properties. Some methods are oxidation, reverse osmosis, ion exchange, electro-dialysis, electrolysis, adsorption etc. Of course, reverse osmosis, ion exchange, electro-dialysis, electrolysis and adsorption are excellent technologies. The water treatment costs of these technologies ranges from 10e450 US$ per cubic meter of treated water; except adsorption technology. The cost of water treatment using adsorption is 5.0e200 US$ per cubic meter of water (Gupta et al., in press). Adsorption is considered as the best wastewater treatment method due to its universal nature, inexpensiveness and ease of operation. Adsorption can also remove soluble and insoluble organic pollutants. The removal capacity by this method may be up to 99.9%. Due to these facts, adsorption has been used for the removal of a variety of organic pollutants from various contaminated water sources. Basically, adsorption is the accumulation of a substance at a surface or interface. In case of water treatment, the process occurs at an interface between solid adsorbent and contaminated water. The pollutant being adsorbed is called as adsorbate and the adsorbing phase as adsorbent. Some reviews have also been written in this area (Aksu, 2005; Ali, 2011; Holden, 1982; Inoue and Kawamoto, 2008; Pollard et al., 1992; Streat et al., 1995; Wigmans, 1989) but no one is focusing especially on the removal of organic pollutants. Various types of organic pollutants have been found in different water bodies. These organic pollutants may be pesticides, fertilizers, hydrocarbons, phenols, plasticizers, biphenyls, detergents, oils, greases, pharmaceuticals etc (Ali and Aboul-Enein, 2004; Damià, ۲۰۰۵; Meyers, 1999). Their side effects and toxicities were well established and reported by many workers (Köhler et al., 2006; Meyers, 1999; WHO report, 2010). The general characteristics of organic pollutants are; presence of one or more cyclic ring either of aromatic or aliphatic nature, lack of polar functional groups, and a variable number of halogen substitutions, usually chlorine. Due to these characteristics they are persistent in the environment (Shatalov et al., 2004). In view of the importance of water quality and environmental aspect, it is considered worthwhile to describe the state-of-art of adsorption for the removal of organic pollutants using low cost adsorbents. 2. Development of low cost adsorbents 2.1. Selection of the precursors Selection of the precursor for the development of low cost adsorbents depends upon many factors. The precursor should be freely available, inexpensive and non-hazardous in nature. Moreover, for good adsorption results, high contents of carbon or oxygen in the adsorbent moiety are very necessary. Other characteristics include high abrasion resistance, high thermal stability and small pore diameters, which results in higher exposed surface area and, hence, high surface capacity for adsorption. 2.2. Types of precursors The choice of the precursor depends upon the nature of origin, i.e. inorganic or organic. Organic precursors include plant, animal and other materials having high carbon content, like fruit waste, rice husks, bark, seaweed, algae, peat moss, hair and keratin etc. Industrial organic products include petroleum and fertilizer products. The inorganic precursors include soil, clay, mud, zeolites, ore materials, metal oxides and hydroxides. 2.3. Processing method In 1940s activated carbon was used as an adsorbent for wastewater treatment (Cheremisinoff and Ellerbusch, 1979; Weber and Vanvliet, 1980). But activated carbon is costly and cannot be used at large scale. This situation compelled scientists toward the development of low cost adsorbents i.e. alternatives of activated carbon (Ali, 2011; Bhattacharya and Venkobachar, 1984; Nawar and Doma, 1989; Srivastava et al., 1987). The use of waste products for developing low cost adsorbents contributes to the waste minimization, recovery and reuse (Patteson, 1989). Activated carbon includes a broad range of carbonaceous materials, which exhibits a high degree of porosity and extended inter particulate surface area (Bansal et al., 1988). A huge variety of carbon containing feed stocks are utilized to prepare activated carbon of different grade; preferably by the catalytic activation of an initially pyrolysed char. Typically activated carbons possess high surface area (600e2000 m2 g1 ) and well defined microporous structure (average pore opening is about 1.5 nm) (Streat et al., 1995). Principally, commercial carbons are prepared from pine wood and coal but there is a continuous search for the inexpensive alternatives. The most common feed stocks for the production of activated carbon at commercial scale are wood, anthracite and bituminous coal, lignite, peat and coconut shell. Alternative feed stocks such as olive stones and almond shells were also used (Bansal et al., 1988; Holden, 1982). The carbon contents of these precursors range from 40 to 90% (w/w) with bulk density range of 0.40e1.45 g cm3 . Activated carbon is prepared in a two stage operation involving carbonization of the raw material below 800 C in the absence of oxygen; followed by activation at elevated temperatures using an oxidant (steam, carbon dioxide or air) and sometimes catalyst. The heating rate as well as time for carbonization and activation are among the important parameters, which affect the final pore structure, surface area and chemistry of the carbon prepared (Rodriguez-Reinoso, 1986; Wigmans, 1986, 1989). 3. Carbonization and activation During carbonization, pyrolytic decomposition of precursor occurs together with the concurrent elimination of many noncarbon species (H, N, O and S) (Fitzer et al., 1971). In this process, low molecular weight volatiles are first released; followed by light aromatics and finally, hydrogen gas (Hucknall, 1985). The resultant product obtained is in the form of a fixed carbonaceous char (Lewis, 1982). The pores formed during carbonization are filled with tarry pyrolysis residues and require activation in order to develop the internal surface of the char. Activation may be accomplished via a chemical or physical treatment. In chemical activation, a catalyst is impregnated into the feedstock. The most widely used chemical activators are ZnCl2, H3PO4, H2SO4, KOH, K2S and KCNS (Zor et al., 1998). In this process, a near saturated solution of catalyst impregnated feedstock is dried to influence pyrolysis in such a way that tar formation and volatilization can be kept at minimum. Resulted product is then carbonized and activated in a single action although two separate temperatures are used (Smisek and Cerny, 1970). Chemical activation is performed at temperatures between 400 and 800 C and used for industrially wood based carbons. The catalytically activated product undergoes a post activation treatment for the removal of residual catalyst that can be reclaimed for its reuse. The different waste products used for generating low cost adsorbents are given in Table 1 (Pollard et al., 1992).

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