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بهینه سازی فرآیند برداشت و جدا سازی ریزجلبک به روش انعقاد الکتریکی در چرخه تولید بیودیزل با استفاده از روش سطح پاسخ

نوع مقاله : مقاله پژوهشی

نویسندگان

1 استادیار گروه مکانیزاسیون و مهندسی بیوسیستم، واحد شوشتر، دانشگاه آزاد اسلامی، شوشتر، ایران

2 استاد گروه مکانیزاسیون و مهندسی بیوسیستم، واحد علوم و تحقیقات، دانشگاه آزاد اسلامی، تهران، ایران

چکیده

یکی از گلوگاه های موجود در فرآیند تولید انبوه زیست توده ریزجلبک در چرخه تولید بیودیزل، نبود روش مناسب برای برداشت و جداسازی زیست توده از محیط کشت است. یکی از مکانیزم های جایگزین برای برداشت ریزجلبک از محیط کشت، استفاده از روش انعقاد الکتریکی است. در این تحقیق به منظور بررسی کارایی و یافتن پارامترهای بهینه فرآیند انعقاد الکتریکی در برداشت و جدا سازی ریزجلبک دونالیلا سالینا، اثرات پنج متغیر کنترلی (مستقل) شامل: جنس الکترود در دو سطح آلومینیوم و آهن، شدت جریان، مدت زمان انعقاد، فاصله الکترود ، سرعت هم زنی، بر روی بازده جداسازی به عنوان متغیر واکنشی (وابسته)، آزمایش هایی بر اساس روش سطح پاسخ چند عاملی با عامل های ترکیبی کمی و کیفی طراحی و انجام شد. نتایج نشان داد که اثر خطی متغیر های کنترلی مورد مطالعه روی بازده جدا سازی بسیار معنی دار است. بطوریکه با افزایش متغیر های شدت جریان الکتریکی و مدت زمان انعقاد و یا کاهش فاصله الکترودها بازده جداسازی به طور معنی دار (01/0>p) افزایش یافته است. همچنین با افزایش دور هم زن میزان بازده جدا سازی با یک شیب تند افزایش و سپس با یک شیب ملایم کاهش یافته است. نتایج نشان داد که الکترودها ی آلومینیوم در جداسازی ریزجلبک از محیط کشت نسبت به الکترود های آهنی کاراتر است. حداکثر بازده جدا سازی با 98 درصد با الکترود آلومینیوم و با اعمال شدت جریان 999 میلی‌آمپر، فاصله الکترود ها 39/1سانتی‌متر، طول مدت انعقاد 20 دقیقه، سرعت هم‌زن 222 دور در دقیقه، حاصل گردید.

کلیدواژه‌ها

عنوان مقاله [English]

Optimization of Microalgae Harvesting and Separation Process by Electrical Coagulation in Biodiesel Production Cycle Using Response Surface Methodology

نویسندگان [English]

  • Heydar Mohammad-ghasemnejad maleki 1
  • Morteza Almassi 2
  • nima nasirian 1

1 Department of Agricultural Mechanization, Shoushtar Branch, Islamic Azad University, Shoushtar, Iran

2 Department of Agricultural Mechanization, Science and Research Branch, Islamic Azad University, Tehran, Iran

چکیده [English]

Introduction Algae have demonstrated to be an efficient bio energy source because in contrast to sugarcane, soybean, canola and oil palm, algae are not edible, they are less expensive to produce, grow faster, allow higher yield and production rate per hectare, do not require clean water to grow, and have the potential of reducing carbon emission. Because of their small size (typically a few micrometer) and low concentration in the culture medium (0.5–2 gL-1), harvesting microalgae biomass is a major challenge. The main goal of this study was to demonstrate the proof of principle for harvesting of microalgae using electro-coagulation-flocculation and to investigation the influence of several important variable on the efficiency of the electro-coagulation-flocculation in harvesting and separating Dunaliella salina microalgae from the culture medium. This is a native species and halophyte microalgae with a different culture medium from the fresh water in terms of salinity and electrical conductivity.
Materials and Methods In order to investigate the effects of five control variables (independent) was included: material of the electrodes on both levels of aluminum and iron; current intensity in the range of 300 to 1000 mA; time for electro-coagulation-flocculation, 5 to 20 minutes; the electrode gap, 1 to 3 cm; stirring speed between 0 to 400, on the recovery efficiency as the response variable (dependent) experiments based on multi factors response surface method (combining categorical with numeric factors) was designed.
In this study, the experiments were made inside a batch reactor with an effective volume of 250 mm which is made of Pyrex glass. Two electrodes with dimensions of 5 × 5 cm and a surface area of 25 cm2 with distance 2 cm from bottom of the reactor in vertically state and in different stages were placed inside the reactor with distance of 1, 2 and 3 cm. The Voltage and required current in the reactor were provided with a digital DC power supply. The main pilot in shape of cubic rectangular which is made of plexiglass with dimensions 35 × 28 × 18 cm and the effective volume of 14 liters was designed and built, in order to test the results of optimal experiments. For designing an experiment, statistical analysis and optimization was used from the software Design-Expert.
Results and Discussion In this study, the modified quadratic model was used to fit the microalgae recovery efficiency data obtained from each batch test. The coefficients of determination (R2), adjusted and predicted were respectively more than 0.98, 0.96 and 0.90, which indicated that the modified quadratic model could describe the microalgae recovery efficiency in the batch tests of this study successfully. The results indicated that the linear effect of control variable on the recovery efficiency is very statistically significant. Moreover with increasing the electric current intensity variable and ECF time, or reduce the distance between the electrodes, the recovery efficiency has increased significantly. Also by increasing stirrer speed from 0 to 200 rpm the amount of recovery efficiency is increased, and by increasing stirrer speed from 200 to 400 rpm the amount of recovery efficiency has decreased. The results showed that aluminum electrodes on the recovery of microalgae from the culture medium are more efficient than iron electrodes. In this study, were searched the optimal operating conditions with aims of maximization of the microalgae recovery efficiency. The maximum microalgae recovery efficiency of 98.06% was obtained at the current intensity of 999 mA, the time of 20 min, the electrode gap of 1.39 cm, the stirring speed of 222 rpm and with aluminum as electrode material
Conclusion In this study was examined the effect of five control variables (independent) including: current intensity, electrode gap, ECF time, stirring speed and electrode material on the response variable (dependent) the recovery efficiency of Dunaliella salina microalgae from the culture medium. The modified quadratic model was used to fit the microalgae recovery efficiency data obtained from each batch test.
The experimental results in different stages of our study indicated that the harvesting efficiency of the ECF process could be improved with optimized settings in different stages. If you want to achieve the maximum efficiency with considering economic factors, energy and environment, the second part of an article by the same research group that focuses on this topic is recommended. However, as the ECF process is complicated on a large scale, a pilot study is required to further adjust the harvesting efficiency and make alterations in current density and electrode plate distance in the ECF harvester so as to develop such technology and make commercial use of it in the future.

کلیدواژه‌ها [English]

  • Electro Coagulation
  • Microalgae
  • Harvesting
  • Recovery Efficiency
مراجع

  1. References

    1. Arslan-Alaton, I., Kabdaşlı, I., Hanbaba, D. and Kuybu, E. 2008. Electrocoagulation of a real reactive dyebath effluent using aluminum and stainless steel electrodes. Journal of Hazardous Materials, 150(1): 166-173.
    2. Bensadok, K., Benammar, S., Lapicque, F. and Nezzal, G. 2008. Electrocoagulation of cutting oil emulsions using aluminium plate electrodes. Journal of Hazardous Materials, 152(1): 423-430.
    3. Canizares, P., Carmona, M., Lobato, J., Martinez, F. and Rodrigo, M. 2005. Electrodissolution of aluminum electrodes in electrocoagulation processes. Industrial and Engineering Chemistry Research, 44(12): 4178-4185.
    4. Duan, J. and Gregory, 2003. Coagulation by hydrolysing metal salts. Advances in Colloid and Interface Science, 100: 475-502.
    5. Escobar, C., Soto-Salazar, C. and Toral, M.I. 2006. Optimization of the electrocoagulation process for the removal of copper, lead and cadmium in natural waters and simulated wastewater. Journal of Environmental Management, 81(4): 384-391.
    6. Fayad, N., Yehya, T., Audonnet, F., and Vial, C. 2017. Harvesting of microalgae Chlorella vulgaris using electro-coagulation-flocculation in the batch mode. Algal Research, 25, 1–11. https://doi.org/10.1016/j.algal.2017.03.015
    7. Gao, S., Yang, J., Tian, J., Ma, F., Tu, G. and Du, M. 2010. Electro-coagulation–flotation process for algae removal. Journal of Hazardous Materials, 177(1-3): 336-343.
    8. Grima, E.M., Belarbi, E.-H., Fernández, F.A., Medina, A.R. and Chisti, Y. 2003. Recovery of microalgal biomass and metabolites: Process options and economics. Biotechnology Advances, 20(7-8): 491-515.
    9. Kim, J., Ryu, B.-G., Kim, B.-K., Han, J.-I. and Yang, J.-W. 2012. Continuous microalgae recovery using electrolysis with polarity exchange. Bioresource Technology, 111: 268-275.
    10. Kim, T.-H., Park, C., Shin, E.-B. and Kim, S. 2002. Decolorization of disperse and reactive dyes by continuous electrocoagulation process. Desalination, 150(2): 165-175.
    11. Matos, C.T., Santos, M., Nobre, B.P. and Gouveia, L. 2013. Nannochloropsis sp. biomass recovery by Electro-Coagulation for biodiesel and pigment production. Bioresource Technology 134, 219-226.
    12. Mollah, M.Y.A., Schennach, R., Parga, J.R. and Cocke, D.L. 2001. Electrocoagulation (EC)-science and applications. Journal of Hazardous Materials, 84(1): 29-41.
    13. Nanseu-Njiki, C.P., Tchamango, S.R., Ngom, P.C., Darchen, A. and Ngameni, E. 2009. Mercury (II) removal from water by electrocoagulation using aluminium and iron electrodes. Journal of Hazardous Materials, 168(2-3): 1430-1436.
    14. Pandey, A., Shah, R., Yadav, P., Verma, R. and Srivastava, S. 2020. Harvesting of freshwater microalgae Scenedesmus sp. by electro–coagulation–flocculation for biofuel production: effects on spent medium recycling and lipid extraction. Environmental Science and Pollution Research, 27(3): 3497-3507.
    15. Song, S., He, Z., Qiu, J., Xu, L. and Chen, J. 2007. Ozone assisted electrocoagulation for decolorization of CI Reactive Black 5 in aqueous solution: An investigation of the effect of operational parameters. Separation and Purification Technology, 55(2): 238-245.
    16. Spolaore, P., Joannis-Cassan, C., Duran, E. and Isambert, A. 2006. Commercial applications of microalgae. Journal of Bioscience And Bioengineering, 101(2): 87-96.
    17. Zaied, M. and Bellakhal, N. 2009. Electrocoagulation treatment of black liquor from paper industry. Journal of Hazardous Materials, 163(2-3): 995-1000.
    18. Zhu, B., Clifford, D.A. and Chellam, S. 2005. Comparison of electrocoagulation and chemical coagulation pretreatment for enhanced virus removal using microfiltration membranes. Water Research, 39(13): 3098-3108.
    19. Zongo, I., Maiga, A.H., Wéthé, J., Valentin, G., Leclerc, J.-P., Paternotte, G. and Lapicque, F. 2009. Electrocoagulation for the treatment of textile wastewaters with Al or Fe electrodes: Compared variations of COD levels, turbidity and absorbance. Journal of Hazardous Materials, 169(1-3): 70-76.
    20. Valdivia, P. 2011. An optimal harvesting and dewatering system mechanism for microalgae. Tarım Makinaları Bilimi Dergisi, 7(2): 211-215.
    21. Vandamme, D., Pontes, S.C.V., Goiris, K., Foubert, I., Pinoy, L.J.J. and Muylaert, K. 2011. Evaluation of electro‐coagulation–flocculation for harvesting marine and freshwater microalgae. Biotechnology and Bioengineering, 108(10): 2320-2329.
    22. Wong, Y., Ho, Y., Leung, H., Ho, K., Yau, Y. and Yung, K. 2017. Enhancement of Chlorella vulgaris harvesting via the electro-coagulation-flotation (ECF) method. Environmental Science and Pollution Research, 24(10): 9102-9110.
مهندسی زراعی
دوره 43، شماره 3
آذر 1399
صفحه 425-440
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هم رسانی
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