Modares Civil Engineering journal
مهندسی عمران مدرس
MCEJ
Engineering & Technology
http://mcej.modares.ac.ir
1
admin
2476-6763
10.22034
fa
jalali
1395
8
1
gregorian
2016
11
1
16
5
online
1
fulltext
fa
بررسی کارایی فرایند US/H2O2 در حذف بنزآلدئید از محلول های آبی
Evaluation of Ultrasound/H2O2 Process Efficiency in Removal of Benzaldehyde from Aqueous Solutions
- هدف از انجام این مطالعه، بررسی و ارزیابی فرایند اکسیداسیون پیشرفته US / H2O2 در تخریب ترکیب سمی بنزآلدئید می باشد. در این راستا اثر پارامترهای pH، غلظت اولیه بنزآلدئید، غلظت اولیه هیدروژن پراکسید، دامنه ارتعاش و فرکانس التراسونیک روی تخریب بنزآلدئید مورد مطالعه قرارگرفت. نتایج نشان داد که تخریب بنزآلدئید در سیستم US / H2O2 تحت تاثیر پارامترهای pH، غلظت اولیه بنزآلدئید، غلظت اولیه هیدروژن پراکسید، دامنه ارتعاش و فرکانس التراسونیک است. میزان تخریب بنزآلدئید با التراسونیک تنها در غلظت 10 میلی گرم بر لیتر از بنزآلدئید، pH=3 ، فرکانس 1 سیکل بر ثانیه و دامنه ارتعاش 100 میکرومتر در حدود 80% بدست آمد. نتایج درصد حذف بنزآلدئید با پراکسید هیدروژن تنها در غلظت 10 میلی گرم بر لیتر از بنزآلدئید، غلظت 100 میلی گرم بر لیتر از هیدروژن پراکسید و pH=3 ذرحدود 16% بود. نتایج نشان داد که هیدروژن پراکسید تنها برای تخریب بنزآلدئید موثر نیست در حالیکه ترکیب H2O2 با التراسونیک درصد تخریب بنزآلدئید را افزایش داده است. به طوریکه در مدت زمان 60 دقیقه، دامنه ارتعاش 100، فرکانس 1 سیکل بر ثانیه، غلظت بنزآلدئید 10 میلی گرم بر لیتر ، غلظت هیدروژن پراکسید 100 میلی گرم بر لیترو pH=3، بیشترین درصد حذف با راندمان 91% حاصل شد. مطابق نتایج تخریب بنزآلدئید در فرآیند التراسونیک / هیدروژن پراکسید با سینتیک شبه مرتبه اول تطابق خوبی داشت. بنابراین تخریب سونوشیمیایی بنزآلدئید با فرایند US / H2O2 می تواند روش موثری برای حذف بنزآلدئید از محلولهای آبی باشد.
Aromatic aldehydes are toxic compounds present in different waste-waters coming from the chemical and petrochemical industries. Their environmental fate may end up by their occurrence in the ground water through the infiltration/deep percolation processes of rain and snow water. Therefore, this kind of substances is contained not only in various industrial wastewaters, but occasionally also in drinking water. Hence, the degradation of such compounds in water and wastewater is still of special interest for many researchers. Benzaldehyde is an aromatic aldehydes used chiefly as a precursor to other organic compounds, ranging from pharmaceuticals to plastic additives and it has been classified as a hazardous substance by the United States Environmental Protection Agency. As a result, the use of alternative treatment technologies, aiming to mineralize or transform refractory molecules into others which could be further biodegraded, is a matter of great concern. Among them, advanced oxidation processes (AOPs) have already been used for the treatment of water and wastewater containing recalcitrant organic compounds such as pesticides, surfactants, colouring matters, pharmaceuticals and endocrine disrupting chemicals. Moreover, they have been successfully used as pretreatment methods in order to reduce the concentrations of toxic organic compounds that inhibit biological wastewater treatment processes. The main mechanism of AOPs function is the generation of highly reactive free radicals. Hydroxyl radicals (HO•) are effective in destroying organic chemicals because they are reactive electrophiles (electron preferring) that react rapidly and nonselective with nearly all electron-rich organic compounds. They have an oxidation potential of 2.33 ev and exhibit faster rates of oxidation reactions comparing to conventional oxidants such as O3. The diverse methods used for generating these radicals are photo catalysis and sonochemistry methods. A new alternative sonochemistry approach offers a solution for combating the persistent water and wastewater organic pollutants. Sonochemical degradation could be used for organic pollutant removal in aqueous solutions. The advantages of using ultrasound irradiation are the simplicity of its use , the ultrasound does not require additional chemicals, and it can be used for treatment of turbid solutions. In this research, ultrasonic/H2O2 advanced oxidation process has been studied for degradation of aqueous solution of benzaldehyde. The effect of key parameters such as ultrasonic frequency, ultrasonic amplitude, time, pH of solution and initial concentration of the benzaldehyde on the removing rate of benzaldehyde are investigated. Different concentrations of benzaldehyde and H2O2 were prepared and the solutions were exposed to ultrasonic treatment (UP 400S model). The experiments was carried out in a batch reactor for 60 min and each 5 min an aliquot was taken from the solutions. Absorbance of sampling solutions was recorded by UV-Vis spectrophotometer of Hack (DR 5000-15 V model). The results show that, the removal rate increases with the increase of time, ultrasonic frequency and amplitude and decreases with the increase of solution pH, H2O2 and benzaldehyde concentrations. As data shown, the degradation of benzaldehyde in ultrasonic/ H2O2 process best fitted by pseudo first order kinetic. It can be conclude the combined of ultrasonic/ H2O2 led to 91% degradation of benzaldehyde after 60 min.
بنزآلدئید,التراسونیک,هیدروژن پراکسید,تخریب
Benzaldehyde,Ultrasound,H2O2,degradation
119
127
http://mcej.modares.ac.ir/browse.php?a_code=A-16-17826-1&slc_lang=fa&sid=16
پروین
غربانی
100319475328460047644
100319475328460047644
Yes
عضو هیات علمی
علی
مهری زاد
100319475328460047057
100319475328460047057
No
مدیر پزوهش