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کاربرد گرافن اکسید پلیمره شده برای بهینه سازی حذف اورتو زایلن از آب توسط روش رویه پاسخ | ||
| محیط شناسی | ||
| مقاله 1، دوره 44، شماره 1، خرداد 1397، صفحه 1-15 اصل مقاله (838.16 K) | ||
| نوع مقاله: مقاله پژوهشی | ||
| شناسه دیجیتال (DOI): 10.22059/jes.2018.239006.1007479 | ||
| نویسندگان | ||
| آویده عزیزی1؛ الهام منیری* 2؛ امیر حسام حسنی3؛ همایون احمد پناهی4؛ فاطمه کاهی5 | ||
| 1دکتری مهندسی محیط زیست، دانشکده محیط زیست و انرژی، دانشگاه آزاد اسلامی واحد علوم و تحقیقات تهران، تهران، ایران. | ||
| 2دانشیار گروه شیمی، دانشگاه آزاد اسلامی واحد ورامین، پیشوا، تهران، ایران | ||
| 3دانشیار گروه مهندسی محیط زیست، دانشکده محیط زیست و انرژی، دانشگاه آزاد اسلامی واحد علوم و تحقیقات تهران، تهران، ایران. | ||
| 4استاد گروه شیمی، دانشگاه آزاد اسلامی واحد تهران مرکزی، تهران، ایران. | ||
| 5کارشناسی مهندسی شیمی، رئیس روابط عمومی شرکت ملی پخش فرآورده های نفتی ایران، تهران، ایران. | ||
| چکیده | ||
| در این تحقیق، میزان حذف اورتو زایلن با استفاده از گرافن اکسید پیوند داده شده با پلیمر متیل وینیل کتون و آنیلین توسط روش رویه پاسخ مورد بررسی قرار گرفت. آماده سازی جاذب با استفاده از فرایند پلیمریزاسیون توسط آغازگر آمونیوم پر سولفات و پلیمر متیل وینیل کتون انجام شد. سپس، محصول توسط آنیلین اصلاح شد. جاذب نهایی توسط طیف سنج مادون قرمز تبدیل فوریه، میکروسکوپ الکترونی روبشی، طیف سنجی پراش انرژی پرتو ایکس و آزمایش بی ای تی آنالیز شده است. برای کاهش تعداد آزمایشات، از روش رویه پاسخ استفاده شد و تاثیر پارامترهای منتخب (زمان تماس، pH و میزان جاذب) بر روی جذب اورتو زایلن از آب مورد آزمایش قرار گرفت. بعلاوه، شرایط بهینه برای رسیدن به درصد حذف 75 % بدست آمد ( زمان تماس برابر با 11 دقیقه، pH برابر با 4/35 و میزان جاذب برابر با 2/43 گرم بر لیتر). نتایج حاصله نشان داد که درصد حذف اورتو زایلن با غلظت اولیه 20 میلی گرم بر لیتر تحت شرایط بهینه، برابر با 74/5% بوده است. در این مقاله میزان ضریب همبستگی برای جذب اورتو زایلن 99/27% بدست آمد که نشان می دهد مدل دارای اعتبار می باشد. | ||
| کلیدواژه‌ها | ||
| جذب؛ گرافن اکسید؛ پلیمریزاسیون؛ اورتو زایلن؛ روش رویه پاسخ | ||
| عنوان مقاله [English] | ||
| Application of polymerized graphene oxide for optimization of o-xylene removal from aqueous solutions through response surface methodology | ||
| نویسندگان [English] | ||
| Avideh Azizi1؛ Elham Moniri2؛ Amir Hessam Hassani3؛ Homayon Ahmad Panahi4؛ Fateme Kahi5 | ||
| 1Ph.D in Environmental Engineering, Department of Environmental Engineering, Faculty of Environment and Energy, Science and Research Branch, Islamic Azad University, Tehran, Iran. | ||
| 2Associate Professor, Department of Chemistry, Varamin (Pishva) Branch, Islamic Azad University, Pishva, Tehran, Iran | ||
| 3Associate Professor, Department of Environmental Engineering, Faculty of Environment and Energy, Science and Research Branch, Islamic Azad University, Tehran, Iran. | ||
| 4Professor, Department of Chemistry, Central Tehran Branch, Islamic Azad University, Tehran, Iran. | ||
| 5BS in Chemical Engineering, Head of Public Relations, National Iranian Oil Products Distribution Company, Tehran, Iran. | ||
| چکیده [English] | ||
| Introduction Following an accidental oil spill, the removal of surface oil are usually the important concern for decreasing energy loss and damage to the environment. O-xylene is one of the common compounds which exist in the effluent of oil and petroleum industries. Consequently, the removal of o-xylene from groundwater and surface waters is essential. The one of main techniques that are useful for cleaning up the soluble oil are adsorption. Adsorption methods are simple and economical and the removal of toxic chemicals using porous adsorbents has aroused attention. Graphene as a new synthetic 2D allotrope of carbon has advantages as an adsorbent due to its flexible structure. Graphene has a very fine potential as adsorbent material due to its low cost and environmentally friendly product and by the fact that graphene can be reused without any significant change in its adsorption capacity. Materials and Methods Preparation of graphene oxide (GO) GO was prepared from graphite powder by Hummers and Offeman method. Polymerization of GO 2 g of GO powder were dissolved in 20 ml of dimethylformamide with stirring. Then, allylamine (10 ml) was added to the solution by continuous stirring at 160 rpm for 2 days. Later, the mixture was washed via dimethylformamide and filtered, the product was dried at room temperature. The grafting of GO with allylamine (GO-AA) was transferred into the flask and was dissolved in 30 ml of methanol. Next, APS (0.75 g) and MVK (30 ml) were rapidly poured to the solution. The mixture was heated at 60°C in a nitrogen atmosphere for 5 h under stirring. The solution was washed with methanol and filtered. At the end, the product was dried at room temperature. Modification of polymerized GO with methyl vinyl ketone (GO-MVK) At first, GO-MVK was mixed with ethanol (150 ml) and aniline (50 ml) and added into the flask. The mixture was fitted under atmosphere of nitrogen at 40°C for 6 h, with agitation speed of 180 rpm. After filtering, the final product was washed with ethanol and further dried in vacuum oven at 40°C for 3 days. Batch adsorption experiments For batch adsorption experiment, the desired dosage of graphene oxide grafted with poly methyl vinyl ketone and aniline (GO-MVK-ANI) was mixed with 50 ml of aqueous o-xylene solution (20 mg/l) in a 100 ml flask which was shaken using a rotary shaker at 150 rpm at 25 ± 2ºC. Then, the solution was filtered with syringe filter. The concentration of o-xylene was quantified using GC-FID. RSM design RSM is the statistical and mathematical method for designing experiments, building models, and estimating the effects of several factors for desirable responses. This technique is suitable for optimizing the effective parameters with a minimum number of experiments. Herein, the effects of 3 variables in adsorption process including contact time, initial pH and adsorbent dose were investigated with a standard central composite design (CCD). The number of experiments is selected 20 basing on a 23 full factorial CCD for the 3 factors. Five levels of factors were investigated according to the obtained experimental data using MINITAB 16 which are presented in Table 1. Table 1 Experimental range and levels of independent variables Variable Factor Unit Range and level -α -1 0 1 +α Contact time X1 min 10.91 45 95 145 179.09 Initial pH X2 - 4.31 5 6 7 7.68 Adsorbent dose X3 g/L 0.05 0.8 1.9 3 3.75 Finally, the optimum value of parameters has been earned for the selected target (o-xylene removal efficiency) in optimization process of RSM program. Results and Discussion The synthesized product was characterized via Fourier transform-infrared resonance (FTIR) spectroscopy, scanning electron microscopy (SEM), Energy-dispersive X-ray (EDX) spectroscopy and Brunauer-Emmett-Teller (BET) analysis. The total pore volume and average pore diameter of the GO are enlarged by polymerization and modification. The effect of three different parameters including the contact time, initial pH and adsorbent dose on adsorption process of o-xylene using GO-MVK-ANI were investigated. The o-xylene adsorption behavior at different contact time was carried out and shown in Fig. 1a. As can be seen, the maximum o-xylene removal was observed in the initial 10 min of adsorption process. Then, the adsorption capacity became constant, approximately. The effects of pH on adsorption capacity are shown in Fig. 1b. There was no significant change in removal efficiency during the increasing of the pH range. According to Fig. 1c, when adsorbent dose increased, the o-xylene removal efficiency improved. The reasons of this enhancement are that the surface area of the adsorbent, available adsorption sites and also active functional groups are improved with increasing of adsorbent dose. Basing on RSM results, the R2-value is found very high for o-xylene removal (R2 = 99.27%) which is a good confirmation between the experimental and the predicted results. Finally, the optimization of adsorption process was applied for the removal of o-xylene. The experimental checking under optimum conditions (the contact time of 11 min, pH of 4.35 and adsorbent dose of 2.43 g/L) was obtained 74.5% for o-xylene removal efficiency which is close to the model result (75 %). Fig. 1 Main effects of (a) contact time, (b) initial pH and (c) adsorbent dose on o-xylene removal efficiency using GO-MVK-ANI Conclusions The aim of this research was to investigate GO-MVK-ANI to adsorb o-xylene from aqueous solutions. The total pore volume and average pore diameter of GO were improved from (0.016 cm3/g, 4.853 nm) to (0.022 cm3/g, 23.187 nm) by polymerization and modification. Based on the results acquired, adsorption contact time was 11 min. It confirms that this adsorbent has high efficiency in the removal of o-xylene for conditions that need rapid treatment. Moreover, GO-MVK-ANI has high stability in the different ranges of solutions pH. According to the ANOVA results, the model presents high R2-value of 99.27% for o-xylene removal and indicates that the accuracy of the polynomial model was successful. The o-xylene removal efficiency under experimental optimum conditions was obtained 74.5% which confirms close to the RSM results. | ||
| کلیدواژه‌ها [English] | ||
| Adsorption, Graphene oxide, Polymerization, O-xylene, Response Surface Methodology | ||
| مراجع | ||
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