نوع مقاله: مقاله پژوهشی

نویسندگان

1 دانشکده علوم پایه، دانشگاه آزاد اسلامی واحد مراغه، صندوق پستی: 47591-55197، مراغه - ایران

2 پژوهشکده چرخه سوخت هسته‌ای، پژوهشگاه علوم و فنون هسته‌ای، سازمان انرژی اتمی ایران، صندوق پستی: 8486-11365، تهران ـ ایران

3 گروه مهندسی شیمی، دانشکده فنی، دانشگاه تهران، صندوق پستی: 4563-11155، تهران - ایران

چکیده

خطرات زیست محیطی پساب‌های حاوی فلزات سنگین از جمله سرب، توجه پژوهشگران را برای پاک‌سازی آن‌ها با استفاده از روش‌های نوین مانند زیست پالایی متمرکز کرده است. در این مطالعه توانایی جذب زیستی سرب توسط باکتری Bacillus sp. strain STG-83 مورد ارزیابی قرار گرفت. از روش رویه پاسخ با طراحی مرکب مرکزی توسط نرم‌افزار دیزاین اکسپرت جهت بهینه‌سازی پارامترهایی چون pH، مقدار جاذب زیستی و غلظت اولیه سرب استفاده شد. نتایج نشان می‌دهد که مدل درجه دوم پیشنهاد شده توسط نرم‌افزار دیزاین اکسپرت با 9938/0=2R، به خوبی رفتار فرایند را پیش‌بینی کرده و جذب ‌زیستی در 5/4pH=، غلظت اولیه سرب 1-mg.L 95/297، مقدار جاذب 1- g.L1 بهینه می‌شود که برابر با dry weight 1- mg.g595/149 می‌باشد. هم‌چنین داده‌های تجربی با ایزوترم‌های لانگمویر و فروندلیچ برازش شد. نتایج نشان داد که مدل لانگمویر با 961/0=2R مناسب‌تر است. مطالعات سینتیکی نیز نشان داد که ظرفیت جذب در 5 دقیقه به بیش‌ترین مقدار خود می‌رسد. نهایتاً با توجه به پتانسیل ارزشمند این باکتری در جذب زیستی سریع و بالای سرب، Bacillus sp. strain STG-83 به عنوان یک جاذب باکتریایی با ارزشی جهت فرایندهای زیست پالایی سرب معرفی شده و کارایی روش رویه پاسخ در مدل‌سازی و بهینه‌سازی فرایند جذب زیستی سرب توسط باکتری مذکور تأیید می‌گردد.

کلیدواژه‌ها

عنوان مقاله [English]

Optimization of efficient lead removal by Bacillus sp. Strain STG-83 using response surface methodology for bioremediation of contaminated wastewater

نویسندگان [English]

  • S. Salimi 1
  • P. Tajer-Mohammad-Ghazvini 2
  • R. Dabbagh 2
  • E. Eivazi 3

1 Faculty of Basic Sciences, Maragheh Branch, Islamic Azad University, P.O.Box: 55197-47591, Maragheh - Iran

2 Nuclear Fuel Cycle Research School, Nuclear Science and Technology Research Institute, AEOI, P.O.Box: 11365-8486, Tehran - Iran

3 Department of Chemical Engineering, Faculty of Engineering, University of Tehran, P.O.Box: 11155-4563, Tehran - Iran

چکیده [English]

Environmental hazards of wastewater containing metals, including lead, have attracted researchers' attention on their cleanup using novel methods such as bioremediation. In the present study, the biosorption ability of lead by Bacillus sp. Strain STG-83 was evaluated. Response surface methodology with central composite design by the Design Expert software was used to optimize parameters such as pH, biomass concentration, and initial lead concentration. The results showed that the quadratic model proposed by Design Expert software with a correlation coefficient of R2=0.9938 predicted the process behavior properly; lead biosorption by the bacteria was optimized at pH=4.5, initial concentration of lead 297.95 mg. L-1, and the amount of adsorbent 1 g.L-1, which is equal to 149.595 mg. g-1 dry weight. Also, the experimental data were fitted with Langmuir and Freundlich isotherms. The results showed that the Langmuir model is more suitable with R2=0.961. Kinetic studies showed that adsorption capacity reached its maximum value within 5 minutes. Ultimately, due to the valuable potential of this bacterium in rapid and high biosorption of lead, Bacillus sp. strain STG-83 is introduced as a valuable bacterial sorbent for lead bioremediation processes and performance of response surface methodology in modeling and optimizing lead biosorption process by Bacillus sp. strain STG-83 is confirmed.

کلیدواژه‌ها [English]

  • Bacteria
  • Biosorption
  • Bioremediation
  • Lead
  • Experiment design

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