بررسی اثر اسیدیته و اسید هیومیک بر راندمان حذف نیترات از آب‏ توسط نانوذرات آهن صفر

نوع مقاله: مقاله پژوهشی

نویسندگان

1 دانش‌آموخته کارشناسی ارشد علوم خاک، دانشگاه صنعتی شاهرود

2 دانشیارگروه آب و خاک، دانشکده کشاورزی، دانشگاه صنعتی شاهرود

3 دانش‏ آموخته دکترای علوم خاک، دانشگاه تربیت مدرس

چکیده

با توجه به فراوانی نیترات در آب و مشکلات ناشی از آن، حذف آن از جمله اهداف مهم در پالایش آب است. به‌منظور بررسی اثر اسید هیومیک بر کارایی پالایش نیترات توسط نانوذرات آهن صفر، آزمایشی به‌صورت فاکتوریل در قالب طرح کاملاً تصادفی در سه تکرار انجام شد. در این مطالعه نانوذرات آهن صفر ظرفیتی به‌روش هم‏رسوبی سنتز و برای بهبود پایداری در محیط آبی بر روی ذرات شن تثبیت شدند. غلظت‏های مختلف اسید هیومیک شامل 0، 25/0 ، 75/0 میلی‏گرم در لیتر و غلظت نانوذرات آهن صفر ظرفیتی شامل 1، 5/1 و 2 میلی‏گرم در لیتر بود و سپس تغییرات محتوی نیترات در محلول مورد ارزیابی قرار گرفت. نتایج نشان داد که نانوذرات آهن صفر ظرفیتی قادراند نیترات محلول در آب را احیا کنند و در نتیجه موجب حذف آن از محلول ‏شوند. حضور اسید هیومیک راندمان حذف نیترات توسط نانوذرات آهن صفر را کاهش می‏دهد. بیشترین حذف نیترات حدود 58 درصد در pH برابر 4 و غلظت نانوذرات آهن صفر ظرفیتی برابر 1 میلی‏گرم در لیتر و کمترین میزان حذف نیترات حدود 7/3 درصد در pH برابر 5 و غلظت نانوذرات آهن 2 میلی‏گرم در لیتر مشاهده شد. نتایج این آزمایش نشان داد که اسید هیومیک عامل مهمی در احیای نیترات بوده و این تأثیر در غلظت‏های پایین‏تر اسید هیومیک بیشتر است. بیشترین راندمان احیای نیترات توسط نانوذرات آهن صفر، در عدم حضور اسید هیومیک در pH برابر 4 معادل 44 درصد بود. همچنین مناسب‏ترین مقدار pH برای حذف نیترات برابر 4 و راندمان حذف در این pH به‌طور میانگین 34 درصد مشاهده شد.
 

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Effect of Humic Acid and Acidity on Nitrate Removal from Water Using Zero Valent Iron Nanoparticles (FeNps)

نویسندگان [English]

  • nasibeh shakeri 1
  • Hadi Ghorbani 2
  • M.H. Ghafariyan 3
1 . Former Graduate Student of Soil Sciences, Shahroud University of Technoloty, Shahroud
2 Assoc. Prof. of Soil and Water, Faculty of Agriculture, Shahroud University of Technology, Shahroud
چکیده [English]

Nitrate is a wide spread pollutant whose removal from aquesous solutions is a major goal of water treatment processes. The present experiment was conducted using a randomized complete block split design with three replications to investigate the effects of humic acid on the nitrate removal efficiency of nanoscale zero-valent iron particles. For this purpose, nanoscale zero-valent iron particles were synthesized using the co-precipitation method and stabilized on sand fractions to achieve better stability in the water environment. Different concentrations of humic acid (0, 0.25, and 0.75 mg/l) and nanoscale zero-valent iron particles (1, 1.5, and 2 mg/l) were used as the variables to evaluate the resulting changes in the water nitrate content. Results showed that nanoscale zero-valent iron particles were able to reduce nitrate ions and, thereby, remove it from the solution. Humic acid was found to reduce the nitrate removal efficiency of nanoscale zero-valent iron particles. The highest nitrate removal (58%) occurred at pH 4 with a nanoscale zero-valent iron concentration of 1 mg/l while the lowest was observed at pH 3.7% with a nanoscale zero-valent iron concentration of 2 mg/l. Humic acid, especially at its lower concentrations, also proved to be an important factor involved in reducing nitrate. In the absence of humic acid, the highest nitrate reduction efficiency of 44% was observed at pH 4. Finally, a pH value of 4 was found to be the optimum level for nitrate removal, which led to an average removal efficiency of 34%.

کلیدواژه‌ها [English]

  • Humic Acid
  • Nitrate
  • reduction
  • nZVI
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