بررسی سینتیکی و ترکیبات میانی ناشی از حذف اسید اورانژ 7 توسط فرایند هیبریدی ازن‌زنی/فتوکاتالیستی

نویسندگان
فرهاد قادری 1
بیتا آیتی 2
حسین گنجی دوست 1
رسول صراف ماموری 1
1 دانشگاه تربیت مدرس
2 ص.پ. 4838-14155
چکیده
اگر چه دو فرایند ازن‌زنی و فتوکاتالیستی کاربردهای زیادی در حل مشکلات زیست محیطی داشته‌اند اما هزینه بالای فرایند ازن‌زنی و راندمان پائین فرایند فتوکاتالیستی در محیط‌های رنگی بعنوان محدودیت این فرایندها در تصفیه این نوع فاضلاب‌ها محسوب می‌شوند. در این تحقیق از ترکیب دو فرایند ازن‌زنی و فتوکاتالیستی برای حذف رنگزای آزویی اسید اورانژ 7 در یک راکتور ناپیوسته استفاده شد. شرایط بهینه‌ pH برابر با 9 با تابش لامپ UV-A 120 وات، در حضور 128 میلی‌گرم بر لیتر نانوماده و 20 میلی‌گرم بر دقیقه ازن با فشار 1 بار و دبی 1 لیتر بر دقیقه، 50 میلی‌گرم بر لیتر رنگزا پس از 65 دقیقه بطور کامل حذف شد. براساس نتایج آزمایش GC-Mass پس از رنگبری ترکیبات بنزنی فنل، آنیلین و اسید فتالیک و نیز 5 آمینو 1 نفتیل، 1- نفتیل و تتولید شدند که در یک ساعت اول افزایش و سپس کاهش غلظت داشتند. برای حذف ترکیبات میانی تولیدی نفتالینی و بنزنی به ترتیب به 3 و 7 ساعت زمان در شرایط بهینه نیاز بود. واکنش در تمامی شرایط از سینتیک مرتبه اول پیروی کرد که در حالت بهینه به خوبی بر مدل لانگمایر-هینشلوود منطبق بود. در این تحقیق، ضمن استفاده همزمان از مزایای دو فرایند ازن‌زنی و فتوکاتالیستی، معایب هر یک در کنار فرایند دیگر برطرف شد.

کلیدواژه‌ها

عنوان مقاله English

Investigation of kinetic and intermediate products of acid orange7 removal by hybrid ozonation/photocatalytic processes

نویسنده English

Bita Ayati 2
2 P.O.Box 14155-4838
چکیده English

Most of dyes used in production processes caused serious environmental pollution when discharged into the environment. Azo dyes are the most used synthetic compounds in the textile, food, leather and cosmetic industries. Due to their toxicity and hard degradation, these kinds of compounds are classified as environmental hazardous materials that have to be treated before discharging to the environment. Acid orange 7 (AO7) is one of azo dyes that is resistant to aerobic degradation and under anaerobic condition is reduced to potential carcinogenic aromatic amines. Different physical methods such as adsorption, ultrafiltration, reverse osmosis, coagulation and electro coagulation are widely used for efficient dye removal but they just transport contaminants from water to sludge and generate secondary wastes which need more treatment. Advanced oxidation processes (AOPs) are suitable to mineralize dye wastewater. They are almost characterized by the efficient production of hydroxyl radicals. Radicals are highly reactive oxidant. Ozonation and photocatalytic treatment are often applied for decolorization of dye wastewaters. It is reported that ozone is an effective agent for reducing the color of wastewater especially azo dyes. TiO2 photocatalytic process is safe and does not require expensive oxidants, against ozonation. This process classified as an AOP method and can be carried out at mild temperature and pressure. The purpose of this study was to investigate hybrid photocatalytic and ozonation processes. Therefore, according to debarment of light penetration in dye wastewater, decoloration ability of ozone was used for improving photocatalytic process efficiency in a hybrid process. The effect of pH, dye and nano catalyst concentration, irradiation source power and ozone injection rate were investigated on removal efficiency in this process. Dye removal efficiencies decreased with increase in dye concentration and decrease in pH, ozone injection rate, catalyst concentration and irradiation source power. Optimum conditions of the process was occurred in pH of 9, UV-A lamp of 120 W, and nano material concentration of 128 mg/L with 50 mg/L of dye concentration and 20 mg/min of ozone injected (with 1 bar pressure and 1 lit/min of gas flow). In these conditions, dye removal was completed after 65 minutes. The result confirm the cleavage of the azo bonds, benzene and naphthalene rings as a result of treatment. The intensities of the absorbance peak at 485nm decrease rather fast than 230 and 310 nm. This shows that faster degradation of azo band in comparison with benzene and naphthalene rings. GC-MS analysis was performed to identify the intermediate products of process. According to GC-Mass test, 5-amino-1-naphthol, 1-naphthol and benzene compound (phenol, aniline and phthalic acid) were in decolorized solution. These compounds concentration increased in the first hour and then decreased. 3 and 7 hour were needed to reach optimum condition for removing naphthalene and benzene compounds, respectively. Reaction was followed by first order kinetic and was fitted to langmuir–hinshelwood model in optimum condition in all cases. First order reaction rate of decoloration (K) decreased with increase in dye concentration and decrease in pH, catalyst concentration and irradiation source power.

کلیدواژه‌ها English

Azo
dye removal
Kinetic
by-products
] Zhu, C., Wang, L., Kong, L., Yang, X., Wang, L., Zheng, S., Chen, F., Maizhi, F., and Zong, H., "Photocatalytic degradation of azo dyes by supported TiO2+UV in aqueous solution", Chemosphere, 41, 2000, 303-309.
[2] Mohan, S.V., Roa, N.C., Prasad, ,K.K., and Karthikeyan, J., "Treatment of simulated reactive yellow 22 (azo) dye effluents using Spirogyra species", Waste Manage., 22, 2002, 575-582.
[3] Hameed, B.H., Ahmad, A.L., and Latiff, K.N.A., "Adsorption of basic dye (methylene blue) onto activated carbon prepared form rattan sawdust", Dyes Pigm., 75 (1), 2007, 143–149.
[4] Kouba, J.F., and Zhuang, P., "Color removal for textile dyeing wastewater", Fluid/Particle Sep. J., 7 (3), 1994, 87-90.
[5] Lu, X., Yang, B., Chen, J., and Sun, R., "Treatment of wastewater containing azo dye reactive brilliant red X-3B using sequential ozonation and upflow biological aerated filter process", Haz. Mat. J., 161, 2009, 241–245.
[6] Aguedach, A., Brosillon, S., Morvan, J., and Lhadi, E.K., "Photocatalytic degradation of azo-dyes reactive black 5 and reactive yellow 145 in water over a newly deposited titanium dioxide", Appl. Catal, B.57, 2005, 55–62.
[7] Arslan, İ., Balcioğlu, I.A., and Bahnemann, D.W., "Advanced chemical oxidation of reactive dyes in simulated dyehouse effluents by ferrioxalate-Fenton/UV-A and TiO2/UV-A processes", Dyes Pigm., 47, 2000, 207-218.
]8[ ایجادپناه ساروی حسین، «سنتز نانو ذرات دی اکسید تیتانیوم و بررسی کاربرد آن در تصفیه فاضلاب‌های صنعتی»، پایان­نامه کارشناسی ارشد مهندسی معدن(فرآوری مواد معدنی)، دانشگاه تربیت مدرس، 1389.
[9] Alinsafi, A., Evenou, F., Abdulkarim, E.M., Pons, M.N., Zahraa, O., Benhammou, A., Yaacoubi, A., Nejmeddine, A., “Treatment of textile industry wastewater by supported photocatalysis”, Dyes Pigm., 74, 2007, 439-445.
[10] Wu, J., Doan, H., and Upreti, S., “Decolorization of aqueous textile reactive dye by ozone”, Chem. Eng. J., 142, 2008, 156–160.
[11] Chen, T.Y., Kao, C.M., Hong, A., Lin, C.E., and Liang, S.H., “Application of ozone on the decolorization of reactive dyes— Orange 13 and Blue 19”, Desalination, 249, 2009, 1238–1242.
[12] Turhan, K., Durukan, I., Ozturkcan, S.A., and Turgut, Z., “Decolorization of textile basic dye in aqueous solution by ozone”, Dyes Pigm., 92(3), 2012, 897-901.
[13] Department of ‍‍commerce, Iranian import statistics, 1389 A.H.S./2010 C.E. [in Persian].
[14] Esther, F., Tibor, C., and Gyula, O., "Removal of synthetic dyes from wastewaters", Env. Inter., 30, 2004, 953–971.
[15] Aksu, S.K., and Gucer, S., "Investigations on solar degradation of acid orange 7 (C.I. 15510) in textile wastewater with micro-and nanosized titanium dioxide", Turkish J. Eng. Env. Sci., 34, 2010, 275 – 279.
[16] Zhao, H.Z., Sun, Y., Xu, L.N., and Ni, J.R., "Removal of Acid Orange 7 in simulated wastewater using a three-dimensional electrode reactor: Removal mechanisms and dye degradation pathway", Chemosphere, 78, 2010, 46–51.
[17] Wu, Y., Zhang, J., Xiao, L., and Chen, F., "Properties of carbon and iron modified TiO2 photocatalyst synthesized at low temperature and photodegradation of acid orange 7 under visible light", Appl. Surf. Sci., 256, 2010, 4260–4268.
[18] Zhu, X., Zhang, J., and Chen, F., "Hydrothermal synthesis of nanostructures Bi12TiO20 and their photocatalytic activity on acid orange 7 under visible light", Chemosphere, 78, 2010, 1350–1355.
] Liang, X., Zhong, Y., Zhu, S., Zhu, J., Yuan, P., He, H., and Zhang, J., "The decolorization of acid orange II in non-homogeneous Fenton reaction catalyzed by natural vanadium–titanium magnetite", Haz. Mat. J., 181, 2010, 112–120.
[20] Huang, H.H., Tseng, D.H., Juang, L.C., “Heterogeneous photocatalytic degradation of monochlorobenzene in water”, Haz. Mat. J., 156, 2008, 186–193.
[21] Turhan, K., and Turgut, Z., ''Decolorization of direct dye in textile wastewater by ozonization in a semi-batch bubble column reactor'', Desalination, 242, 2009, 256–263.
[22] Barka, N., Assabbane, A., Nounah, A., Aˆıt Ichou, Y., ”Photocatalytic degradation of indigo carmine in aqueous solution by TiO2-coated non-woven fibres”, Haz. Mat. J., 152, 2008, 1054–1059.
]23[ نایبی ­گاوگانی رویا، «حذف رنگ‌های اسیدی توسط فرایند تلفیقی نانو ذرات TiO2 تثبیت شده بر بستر بتن و فرایند بیولوژیکی‏»، پایان­نامه کارشناسی ارشد مهندسی عمران (­محیط­زیست)، دانشگاه تربیت مدرس، 1390.
مهندسی عمران مدرس
دوره 15، شماره 2
خرداد و تیر 1394
صفحه 79-89