حذف همزمان نیترات و فسفات از آب توسط فرایند انعقاد‌ الکتریکی با الکترود آلومینیومی پوشش داده شده با نانوذرات ZnO

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشجوی کارشناسی ارشد مهندسی عمران مهندسی محیط زیست دانشکده فنی و مهندسی دانشگاه خوارزمی

2 گروه مهندسی عمران- دانشکده فنی و مهندسی-دانشگاه خوارزمی- تهران- ایران

چکیده

استفاده بیش از حد از کود‌های نیتروژن­دار باعث حضور آلاینده‌های معدنی نظیر فسفات و نیترات در منابع آب‌های زیرزمینی می­شود. با توجه به خطرات حضور این ترکیبات در آب، یافتن روشی مناسب جهت حذف همزمان این آنیون‌ها از منابع آبی بسیار حائز اهمیت است. هدف از این مطالعه، استفاده از فرایند انعقاد ‌الکتریکی و بررسی اثر پارامتر‌های سختی، فاصله الکترود، نوع پوشش‌دهی الکترود با نانوذرات و اثر ولتامتری چرخه­ای به عنوان متغیر در شرایط غلظت اولیه ۱۰۰ میلی‌گرم بر لیتر از دو آلاینده، دانسیته جریان 22/5 آمپر بر متر مربع، pH برابر ۶ و زمان ماند ۴۰ دقیقه بر حذف نیترات و فسفات به صورت همزمان است. بهترین بازده حذف فسفات و نیترات در فاصله ۲ سانتی‌متری بین الکترود‌ها به ترتیب 93/8 و ۷۸ درصد و در سختی ۶۵ میلی‌گرم بر لیتر کربنات کلسیم به میزان 99/3 و ۸۶ درصد به دست آمد. جهت بهبود فرایند انعقاد الکتریکی و کاهش سرعت غیرفعال شدن آند آلومینیومی، الکترودها با نانوذرات ZnO به روش سل-ژل پوشش­دهی شدند. صحت پوشش‌دهی الکترود با نانوذرات ZnO توسط آنالیزهای SEM، EDX و XRD ارزیابی شد. برای بررسی اثر پوشش‌دهی نانوذرات از آزمایش ولتامتری چرخه‌ای استفاده گردید. نتایج حاکی از بهبود 202/44 درصدی شدت جریان الکتریکی در الکترود اصلاح شده بود.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Simultaneous removal of nitrate and phosphate using aluminum electrode coated by ZnO nanoparticles in electrocoagulation process

نویسندگان [English]

  • Shima Torabinejad-yazdi 1
  • Mohammad Delnavaz 2
1 MSc student of Environmental Engineering, Kharazmi University, Tehran, Iran
2 Civil engineering department, Faculty of Engineering, Civil Engineering Department, Kharazmi University
چکیده [English]

The excessive usage of nitrogen fertilizers leads to phosphate and nitrate become as a common inorganic pollutant in groundwater resources. Therefore,  an alternative process performance seems to be examined to remove these anions from water resources. This study aims to investigate the effect of two variables, water hardness and electrode distance, on the electrocoagulation process for simultaneous phosphate and nitrate removal. For this purpose, initial concentration=100 mg/l, current density=22.5 A/m2, pH=6 and retention time=40 min were considered. Under these conditions, the optimum removal efficiency of phosphate and nitrate were achieved at 2 cm electrode distance with 93.8% and 78%, respectively. While, the water hardness of 65 mg/l CaCO3 was shown 99.3% and 86% removal efficiency, respectively. Then, in order to improve the electrocoagulation process and reduce the passivation rate of the aluminum anode, the electrodes were modified with ZnO nanoparticles by the sol-gel method. The accuracy of electrode coating with zinc oxide nanoparticles was determined by SEM, EDX and XRD tests. The effect of coating was investigated by cyclic voltammetry, showing that current intensity at the modified electrode has improved 202.44%.

کلیدواژه‌ها [English]

  • Electrocoagulation
  • Phosphate and nitrate
  • Sol-gel
  • Cyclic voltammetry
  • ZnO
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