نوع مقاله : مقاله پژوهشی

نویسندگان

• محمد نپتون ¹
• محمد جواد نحوی نیا ²
• جواد مظفری ²
• مژگان زنده دل ³

¹ گروه علوم و مهندسی آب، دانشگاه اراک

² گروه علوم و مهندسی آب دانشگاه اراک

³ گروه شیمی، دانشگاه اراک

چکیده

نانوجاذب‌ها به عنوان یک محصول نوظهور نقش مهمی در کنترل و حذف آلودگی‌های محیطی ایفا می‌کنند. از این رو، در این مطالعه جاذب‌ زئولیت کلینوپتیلولایت و نانو کامپوزیت تهیه شده از نانو ذرات Fe3O4 A Zeolite به منظور حذف یون نیترات از پساب واقعی در سیستم صنعتی تهیه گردید. همچنین تیمار زئولیت و تیمار زئولیت-خاک رس برای مقایسه مورد آزمایش قرارگرفتند. ستون‌های آزمایشگاهی از جنس PVC به ‌ارتفاع یک متر و قطر mm 100 استفاده گردید. ستون‌های مورد بررسی تا ارتفاع 60 سانتی‌متر از مواد مورد بررسی پر شد و بر روی ستون‌ها به اندازه 20 سانتی‌متر پساب به صورت مستمر قرار گرفت. آزمایش به‌صورت فاکتوریل و در قالب طرح پایه کاملا تصادفی در سه تکرار اجرا گردید. نتایج نشان داد نانوکامپوزیت با پایه زئولیت و Fe3O4 توانایی جذب بیش از 70 % نیترات را در مقیاس آزمایشگاهی کوچک و جریان غیرمستمر را داراست. در جریان مستمر و در مقیاس بزرگ آزمایشگاهی که دارای کاربرد صنعتی می‌باشد، میزان جذب نانوکامپوزیت، پس از 8 ساعت جریان مستمر به 27% خواهد رسید. این میزان جذب برای زئولیت-خاک رس 17% و برای زئولیت 4/13% می‌باشد. کاهش زمان تماس و افزایش میزان پساب در جریان مستمر ، سبب کاهش تاثیر جاذب‌ها خواهد شد. نتایج آنالیز واریانس یک طرفه برای مقایسه اثر حذف پساب در مقیاس صنعتی بین‌های جاذب‌های مورد استفاده نشان داد که جاذب نانوکامپوزیت استفاده شده دارای کارایی بیشتری نسبت به جاذب زئولیت و زئولیت/خاک رس می‌باشد. بطور کلی نتایج این تحقیق نشان می‌دهد نانوکامپوزیت استفاده شده در این مطالعه توانایی نسبی در حذف نیترات از محیط آبی دارد و در صورت افزایش زمان تماس، می‌توان در مقیاس صنعتی با درصد جذب مناسبی از آن استفاده کرد.

کلیدواژه‌ها

• پساب
• مقیاس صنعتی
• نانو کامپوزیت
• نیترات

موضوعات

• کیفیت آب

عنوان مقاله [English]

Investigation of Zeolite Efficiency in Nitrate Removal from Urban Wastewater by Fe3O4 Nano Particles in Industrial Scale

نویسندگان [English]

• Mohammad Nepton ¹
• Mohammad Javad Nahvinia ²
• Javad Mozaffari ²
• Mojgan Zendehdel ³

¹ Water science & engineering department, Arak University

² Water Science & Engineering Department, Arak University

³ Chemistry Department, Arak University

چکیده [English]

Introduction:

As a new product, nanoabsorbents play an important role in controlling and removing environmental pollution. Fe3O4 nanoparticles, due to their high absorption level, have a great ability to increase the efficiency of zeolite adsorbents in removing pollutants. Naeej et al. (2013) explained Zeolite modified with zero iron nanoparticles, due to having many absorption sites as a reducing agent, can have a great ability to remove nitrate from drinking water. Yaghmaian et al. (2015) investigated the removal of nitrate from aqueous solutions with zero-valent iron nanoparticles and stated that at a pH of 5.8 and a contact time of 55 minutes, more than 80% absorption is obtained. Qarlaqi et al. (2015) investigated the efficiency of iron oxide nanoparticles for urban sewage treatment. They stated that at pH equal to 3 and contact time of 15 minutes, the maximum amount of absorption is obtained. Therefore, in this study, clinoptilolite zeolite adsorbent and nano composite prepared from A Zeolite Fe3O4 nanoparticles were prepared in order to remove nitrate ions from real wastewater in industrial system. Also, zeolite treatment and zeolite- clay treatment were tested for comparison.



Methods:

In this research, Fe3O4 nanoparticles were used to increase the efficiency of zeolite in removing nitrate from aqueous solutions and real wastewater. Laboratory columns made of PVC material with a height of one meter and a 100 mm diameter were used. The investigated columns were filled up to a height of 60 cm with the investigated materials and 20 cm of wastewater was continuously placed on the columns. The investigated treatments include three adsorbent materials: a) six kilograms of zeolite (clinoptilolite), b) three kilograms of zeolite and three kilograms of clay, and c) six kilograms of nanocomposite prepared from zeolite and nanomagnetic with an optimal ratio (Ratio of Zeolite: 0.5 Fe3O4) was laboratory. Synthetic wastewater with a concentration of 40 ppm was prepared and used. The temperature of the wastewater used was 20 degrees Celsius and the pH of the treated wastewater was measured as 7.2. The experiment was carried out factorially and in the form of a completely random basic design in three replications.



Results:

The results showed that the nano composite based on zeolite and Fe3O4 can absorb 70% of nitrate in a small laboratory scale and non-continuous flow. In continuous flow and on a large-scale laboratory that has industrial application, the absorption rate of nanocomposite will reach 27% after 8 hours of continuous flow. This absorption rate is 17% for zeolite-clay and 13.4% for zeolite. Decreasing the contact time and increasing the amount of wastewater in continuous flow will reduce the effect of absorbents. The results of the average comparison of the nitrate concentration in the wastewater from the columns with different absorbers show that the difference between the nitrate concentration in all measurement times between the nanocomposite absorber and the other two absorbers is statistically significant at the 1% level. Also, the results of one-way analysis of variance to compare the effect of wastewater removal on an industrial scale between the adsorbents used showed that the nanocomposite adsorbent used has more efficiency than zeolite and zeolite-clay adsorbents. Due to the fact that the composition of nanocomposite (zeolite modified with nano Fe3O4) has more surface area than zeolite and clay adsorbent due to having nano compounds, so the reactivity of this adsorbent is increased and nitrate absorption in this adsorbent is more than other adsorbents. In general, the results of this research show that the nanocomposite used in this study has a relative ability to remove nitrate from the water environment, and if the contact time is increased, it can be used on an industrial scale with a suitable absorption percentage. The current research was done with continuous flow and short contact time. This is despite the fact that in most of the investigated studies, the contact time was more than 50 minutes. Therefore, the amount of absorption is less than the laboratory scale and non-continuous flow. To solve this problem, the continuous flow system should be designed in such a way that the contact time reaches at least more than 50 minutes. In addition, with proper design, passing through the filter can be done in two stages so that maximum absorption takes place.

کلیدواژه‌ها [English]

• Wastewater
• Industrial scale
• Nanocomposite
• Nitrate