سنتز و عملکرد نانوکاتالیزورهای اکسید فلزات سریم و نیکل بر پایۀ زیرکونیا به‌منظور تولید بیودیزل‌

امروزه بیودیزل به‌عنوان جایگزینی مناسب برای سوخت‌های فسیلی در نظر گرفته شده است. با توجه به اهمیت زیست‌محیطی بیودیزل، در مطالعۀ حاضر، اکسیدهای zro2nio و zro2ceo2 با نسبت‌های مولی مختلف با استفاده از روش همرسوبی و سل ژل پچینی سنتز شد و فعالیت‌های کاتالیزوری آن‌ها برای تولید بیودیزل از روغن ذرت و روغن پسماند مورد بررسی قرار گرفت. کاتالیزورهای جدید از لحاظ مورفولوژی، کریستالوگرافی و ترکیب شیمیایی با تکنیک‌های شناخته‌شدۀ پراش اشعۀ ایکس، طیف‌سنجی پراش انرژی پرتو ایکس، میکروسکوپ الکترونی روبشی نشر میدانی و طیف‌سنجی مادون قرمز تبدیل فوریه بررسی شدند. عوامل و پارامترهای مختلف موثر در میزان تولید بیودیزل، از جمله نسبت روغن به متانول، دمای واکنش ترانس‌استریفیکاسیون و روش سنتز نانوکاتالیزور برای کاتالیزورهای مورد نظر بهینه شد. نتایج تجربی نشان دادند که استفاده از زیرکونیوم‌‌دی‌اکسید به‌همراه اکسید فلزات به‌عنوان کاتالیزور، باعث افزایش سینتیک و کاهش زمان واکنش تولید بیودیزل می‌شود. همچنین بالاترین عملکرد کاتالیزور در نسبت مولی روغن به متانول (1 به 10) و نسبت مولی 10=zr/ni و 10=zr/ce مشاهده شد، به‌طوری‌ که بازدهی تبدیل روغن پسماند و روغن ذرت به بیودیزل بر روی کاتالیزور zro2ceo2 به‌ترتیب 92 و 83% با دقت تحلیلی رضایت‌بخش (r.s.d≤ 4.8٪) و برای کاتالیزور zro2nio به‌ترتیب 83 و 78% با دقت تحلیلی رضایت‌بخش (r.s.d≤ 5.3٪) به دست آمد.

Synthesis and Performance of Nickle and Cerium Metal Oxide Nanocatalysts Based on Zirconia to Produce Biodiesel

Extended AbstractIntroduction: Recently, biodiesel is considered a suitable alternative for fossil fuels. According to the bioenvironmental importance of biodiesel, in the current study, ZrO2NiO and ZrO2CeO2 oxides with different molar ratios were synthesized using coprecipitation method and Pechini solgel, and their catalytic activities were examined to produce biodiesel from corn oil and waste cooking oil. New catalysts were investigated in terms of morphology, crystallography, and chemicals with wellknown techniques of Xray diffraction, Xray energy diffraction spectroscopy, field emission scanning electron microscopy, and Fourier transform infrared spectroscopy. Different factors and parameters affecting biodiesel production such as oil to methanol ratio, transesterification reaction temperature, and nanocatalyst synthesis method were optimized for the catalysts of interest. The empirical results showed that the use of zirconia with metal oxide as catalyst increases synthetic and decreases reaction time of biodiesel production. Also, the highest catalyst performance was observed in the moral ratio of oil to methanol (1/10) and molar ratios of Zr/Ce and Zr/Ni= 10. Hence, waste cooking oil transformation efficiency and corn oil to biodiesel on ZrO2CeO2 catalysts were 92 and 83% with a satisfactory analytic accuracy (R.S.D≤ 4.8 ٪), and with ZrO2NiO catalyst they were 83 and 78% with a satisfactory analytic accuracy (R.S.D≤ 5.3 ٪). Introduction: In this study, ZrO2based heterogeneous nanocatalysts of nickle and cerium oxides were synthesized through Pechini solgel and coprecipitation methods and applied for the catalytic production of biodiesel from cheap renewable feedstocks (i.e., WCO and corn oil). The prepared binary mixed oxides nanocatalysts were characterized, and different parameters affecting the biodiesel yield were investigated and optimized. The high performance and success of the prepared nanocatalysts in the biodiesel production process were reported.Materials and Methods: The WCO obtained from a fast food and edible corn oil was bought from supermarket. Cerium nitrate (Ce(NO3)3.6H2O), zirconium oxychloride (ZrOCl2.8H2O), nickle nitrate (Ni(NO3)2.6H2O), ethylene glycol ((CH2OH)2), methanol (CH3OH), and sodium hydroxide (NaOH) were of high analytical grade and were bought from Merck Co. (Germany). The ZrO2NiO and ZrO2CeO2 mixed oxides nanocatalysts were synthesized through coprecipitation and Pechini solgel methods.Discussion and Conclusion: The catalytic activities of prepared ZrO2NiO and ZrO2CeO2 mixed oxides with different molar ratios synthesized via Pechini solgel and coprecipitation methods were investigated at different operation conditions. Two synthesis methods had the advantage of simplicity and facility of the process without any need to use complex reactor systems, toxic solvents, and surfactants. The prepared mixed oxides nanocatalysts were successfully applied in biodiesel production from inexpensive WCO and corn oil feedstock associated with high yields. The effect of different reaction parameters on the reaction yield was investigated, and the optimized condition was obtained. Based on the results, the prepared nanocatalyst showed a good catalytic activity and high stability and reusability with high reproducibility. It was seen that both nanocatalysts could be recovered and reused in 4 repeated cycles for the biodiesel production. The results of production yields after 4 sequential cycles pointed out that the synthesized ZrO2NiO and ZrO2CeO2 nanocatalysts had good stability and could be reused with only slight loss in their catalytic activities.