بررسی کارایی فرایند نانوفیلتراسیون در حذف فلزات سنگین سرب، کادمیم، کروم شش ظرفیتی و مس از آبهای حاوی سولفات

نوع مقاله: مقاله پژوهشی

نویسندگان

1 استاد مرکز تحقیقات مهندسی بهداشت محیط و گروه بهداشت محیط دانشگاه علوم پزشکی کرمان

2 دانشجوی کارشناسی ارشد مهندسی بهداشت محیط، گروه بهداشت محیط دانشگاه علوم پزشکی کرمان

3 عضو مرکز تحقیقات بهداشت محیط و مربی گروه بهداشت محیط دانشگاه علوم پزشکی کرمان

چکیده

فلزات سنگین از آلاینده‌های مهم محیط زیست است. هدف از این پژوهش بررسی کارایی غشای نانوفیلتر در حذف فلزات سنگین سرب، کادمیم، مس و کروم شش ظرفیتی از آب‌های حاوی سولفات بود.غشای استفاده شده از نوع NF، مدل حلزونی-مارپیچی و قطر اسمی حد برابر 27 دالتون، با جریان متقاطع و ظرفیت اسمی 8/0 لیتر بر دقیقه بود. اثر متغیرهای غلظت اولیه فلز (دامنه 5تا 50 میلی‌گرم در لیتر برای سرب، کادمیم و مس و دامنه 1/0 تا 4/0 میلی‌گرم در لیتر برای کروم در 4 غلظت)، pH (9-4)، دبی عبوری (2/0، 4/0، 6/0 و 8/0 لیتر بر دقیقه) و غلظت آنیون سولفات (4 غلظت با دامنه 200 تا 800 میلی‌گرم در لیتر) بر کارایی فرایند در حذف فلزات بررسی شد. اندازه‌گیری با روش جذب اتمی و اسپکتروفوتومتری انجام شد.حداکثر راندمان حذف سرب،‌کادمیم، مس و کروم شش ظرفیتی در شرایط بهینه آزمایش به‌ترتیب برابر 91، 97، 98 و 95 درصد در نمونه‌های سنتتیک و 72، 53، 87 و 99 درصد در نمونه‌های واقعی بود. کارایی غشا در حذف سه فلز سرب، کادمیم و مس با افزایش pH و غلظت اولیه فلز نسبت معکوس داشت، اما در حذف کروم شش ظرفیتی،نسبت مستقیم بود. افزایش دبی تا میزان 6/0 لیتر بر دقیقه، افزایش نسبی کارایی غشا را در حذف هر چهار فلز به‌دنبال داشت.غشای NF، راندمان بالایی در حذف چهار فلز داشته و راندمان حذف در حضور یون‌های سولفات و افزایش دبی تا یک محدوده مشخص، به‌طور چشمگیری افزایش یافت. لذا می‌توان از این روش برای حذف آلاینده‌های ذکر شده استفاده نمود.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Survey of Nanofiltration Process Efficiency in Pb, Cd, Cr+6 and Cu Ions Removal from Sulfate-Containing Waters

نویسندگان [English]

  • Mohammad Malakootian 1
  • Abdolali Golpayegani 2
  • Ahmad Rajabizadeh 3
چکیده [English]

Heavy metals have been identified as major pollutants and also as one of the most serious environmental hazards. The aim of this study was to evaluate the efficacy of NF membrane to remove the heavy metals Pb, Cd, Cu and Cr+6 from waters containing sulfate. The membrane used in this study was of the NF, spiral-wounded model with a MWCO equal to 27Da, a cross-flowed stream, and a nominal capacity of 0.8 L/min. The effects of the parameters initial metal concentration (within the range of 5 to 50 mg/L for Pb, Cd, and Cu and 0.1 to 0.4mg/L for Cr+6 at four different concentrations), pH (4-9), flow rate (0.2, 0.4, 0.6, and 0.8 mg/L), and sulfate anion concentration (four concentrations ranging from 200 to 800 mg/L) on heavy metal removal efficiency of the membrane were investigated. Measurements were performed using atomic absorption and spectrophotometry. The maximum removal rates of Pb, Cd, Cu and Cr+6 for synthetic samples under optimal experimental conditions were 91, 97, 98, and 95%, and those for real samples were 72, 53, 87, and 99%, respectively. It was observed that the membrane efficiency for removing the three metals of Pb, Cd, and Cu decreased with increasing pH and initial metal concentration while it increased in the case of Cr+6. Increasing flow to 0.6 L/min led to a slight increase in membrane removal efficiency for all the four metals. Based on the results obtained, NF membranes are capable of removing a high percentage of heavy metals and a significant increase is observed in their heavy metal removal efficiency in the presence of sulfate ions and with increasing flow up to a certain level.

کلیدواژه‌ها [English]

  • Nanofilter
  • Lead
  • Cadmium
  • copper
  • Chromium (VI)
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