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حرية الوصول المقاله
1 - بررسی تصفیه پساب‌های حاوی آنتی‌بیوتیک توسط روش نانوفتوکاتالیزوری
عالیه محمدی شقایق لاله محمدرضا دوستیامروزه همگام با پیشرفت صنعت، آلودگی آب نیز رو به افزایش است. آلاینده ها از مسیرهای گوناگون به منابع زیرزمینی و روان آب های سطحی وارد می شوند و به عنوان تهدیدی بالقوه برای سلامت انسان و سایر جانداران در چرخه حیات قرار می گیرند. با اینکه تاکنون روش های مختلفی برای تصفیه أکثرامروزه همگام با پیشرفت صنعت، آلودگی آب نیز رو به افزایش است. آلاینده ها از مسیرهای گوناگون به منابع زیرزمینی و روان آب های سطحی وارد می شوند و به عنوان تهدیدی بالقوه برای سلامت انسان و سایر جانداران در چرخه حیات قرار می گیرند. با اینکه تاکنون روش های مختلفی برای تصفیه آب و فاضلاب بکار رفته است اما اغلب این روش ها برای حذف بسیاری از آلاینده های آلی پایدار از جمله رنگ ها، داروها، حلال ها، آفت کش ها و غیره کارایی لازم را ندارند. آنتی بیوتیک ها از جمله آلاینده های آلی پایدار هستند که پس از مصرف به ندرت در بدن به طور کامل متابولیزه می شوند و 30 تا 90 درصد آن ها پس از دفع به صورت آلاینده های فعال در محیط زیست باقی می مانند. از این رو استفاده از روش های نوین نظیر فرایندهای فتوکاتالیزوری برای تصفیه آنتی بیوتیک ها مورد توجه پژوهشگران قرار گرفته است. با توجه به زمان کوتاه تولید نانوفتوکاتالیزور ها، قابلیت بازیافت و امکان استفاده مجدد از آن، تشکیل محصولات بی ضرر در طی واکنش، صرفه اقتصادی و سازگاری با محیط زیست، استفاده از نانو فتوکاتالیزور های نیمه هادی ناهمگن به عنوان یکی از فرایندهای اکسیداسیون پیشرفته، می تواند روشی موثر و کارآمد برای مقابله با آلودگی های زیست محیطی ناشی از آنتی بیوتیک ها باشد. در این مطالعه، ضمن معرفی روش اکسیداسیون پیشرفته، به نحوه به کارگیری نانو فتوکاتالیزور های ناهمگن، بررسی تأثیر عوامل عملیاتی مختلف واکنش فتوکاتالیزوری در تصفیه آب و فاضلاب حاوی آنتی بیوتیک ها و مطالعات مختلف و تحقیقات پبشین انجام شده در این زمینه پرداخته شده است. تفاصيل المقالة -
حرية الوصول المقاله
2 - The removal of Hexavalent chromium; (Cr (VI)) by ZnO/LECA as a nano photocatalyst using full factorial experimental design
Aref Shokri Safoora KarimiIn this research, a synthesized nano photocatalyst was prepared by supporting ZnO nanoparticle on Lightweight expanded clay aggregate (LECA). The catalyst was synthesized by co-precipitation method. The SEM, FT-IR and XRD tests were used to characterize ZnO/LECA, which أکثرIn this research, a synthesized nano photocatalyst was prepared by supporting ZnO nanoparticle on Lightweight expanded clay aggregate (LECA). The catalyst was synthesized by co-precipitation method. The SEM, FT-IR and XRD tests were used to characterize ZnO/LECA, which was employed for photocatalytic removal of Cr (VI) from aqueous solution in batch photoreactor. The full factorial experimental design (FFD) was used for the statistical analysis of data. The influence of catalyst amounts, pH, and initial concentration of Cr (VI) was investigated on the reduction of Cr (VI) to Cr (III). The number of active site was increased with increase in the concentration of catalyst to some extent. Also, the selection of other factors in optimized amount was important. The optimal conditions were obtained at 0.75 g/l of photocatalyst, pH at 5 and 20 mg/l of Cr(VI). The experimental and predicted reduction efficiency by FFD at optimal conditions were 97.6 and 96.18%, respectively. The comparison of experimental and predicted data showed a good agreement between them. تفاصيل المقالة -
حرية الوصول المقاله
3 - Application of TiO2/ZnS as a nano photocatalyst for degradation of Acid Red 18 in aqueous media using a central composite design
Aref Shokri Mahdi Sanavi FardIn this study, through the application of TiO2/ZnS as a novel nano photocatalyst, the degradation of AR18 in synthetic wastewater was explored. The nano photocatalyst was synthesized by the co-precipitation method and characterized by Scanning electron microscopy (SEM), أکثرIn this study, through the application of TiO2/ZnS as a novel nano photocatalyst, the degradation of AR18 in synthetic wastewater was explored. The nano photocatalyst was synthesized by the co-precipitation method and characterized by Scanning electron microscopy (SEM), Fourier transfer infrared (FTIR), and X-ray powder diffraction (XRD) techniques. The average size of ZnS/TiO2 nano photocatalyst was 79nm. For experimental design and statistical analysis of each factor including AR18 concentration, pH, catalyst dosage, and treatment time on the degradation rate of AR18 (response) by Central Composite Design (CCD) was used. The analysis of variance (ANOVA) demonstrates a second-order regression model with R2 = 0.9995, adjusted R2=0.9991, and predicted R2=0.9982) for the removal of AR18. The optimum conditions for each operating factor were as the following: AR18 concentration at 30 mg.L-1, catalyst dosage at 1.2 g.L-1, pH at 5, and treatment time at 120 min. In this condition, the actual and predicted AR18 removal was 94% and, 93.07%, respectively. تفاصيل المقالة -
حرية الوصول المقاله
4 - Degradation of Chloridazon in an aqueous environment using TiO2/Ag as a synthesized nano photocatalyst using central composite design
Maysam Abdolkarimi Fariba Soleimani Aref ShokriIn this study, TiO2/Ag nano photocatalyst was synthesized by sol-gel method and used for degradation of Chloridazon (CLZ) in aqueous media. The prepared catalyst was characterized using powder X-ray diffractometry (XRD), Fourier transform infra-red (FTIR), and field emi أکثرIn this study, TiO2/Ag nano photocatalyst was synthesized by sol-gel method and used for degradation of Chloridazon (CLZ) in aqueous media. The prepared catalyst was characterized using powder X-ray diffractometry (XRD), Fourier transform infra-red (FTIR), and field emission scanning electron microscopy (FESEM) techniques. The Crystallite size of pure TiO2 and Ag/TiO2 nanoparticles was 20 and 60 nm, respectively. The Central Composite Design (CCD) was employed for experimental design and statistical analysis of independent operational parameters. According to the results of Response Surface Methodology (RSM) plots of Design-Expert software, the optimal conditions for each critical variable were as the follows: time at 113 min, pH at 6.8, initial concentration of CLZ at 40 mg/l, and catalyst concentration at 0.83gr/l. The maximum effectiveness in the experimental and predicted CLZ removal was 94.2 and 93.5%, respectively. The outcomes of Analysis of variance (ANOVA) demonstrated high determination coefficient quantities (R2 = 0.9997, Predicted R2=0.9989, and Adjusted R2=0.9994) which validated the reliability of the second-order regression model. تفاصيل المقالة -
حرية الوصول المقاله
5 - The removal of Hexavalent chromium; (Cr (VI)) by ZnO/LECA as a nano photocatalyst using full factorial experimental design
Safoora Karimi Aref ShokriIn this research, a synthesized nano photocatalyst was prepared by supportingZnO nanoparticle on Lightweight expanded clay aggregate (LECA). The catalystwas synthesized by the co-precipitation method. The SEM, FT-IR, and XRD testswere used to characterize ZnO/LECA, whic أکثرIn this research, a synthesized nano photocatalyst was prepared by supportingZnO nanoparticle on Lightweight expanded clay aggregate (LECA). The catalystwas synthesized by the co-precipitation method. The SEM, FT-IR, and XRD testswere used to characterize ZnO/LECA, which was employed for photocatalyticremoval of Cr (VI) from an aqueous solution in a batch photoreactor. The fullfactorial experimental design (FFD) was used for the statistical analysis of data.The influence of catalyst amounts, pH, and initial concentration of Cr (VI) wasinvestigated on the reduction of Cr (VI) to Cr (III). The number of active sites wasincreased with an increase in the concentration of catalyst to some extent. Also,the selection of other factors in the optimized amount was important. The optimalconditions were obtained at 0.75 g/l of photocatalyst, pH at 5 and 20 mg/l ofCr(VI). The experimental and predicted reduction efficiency by FFD at optimalconditions were 97.6 and 96.18%, respectively. The comparison of experimentaland predicted data showed a good agreement between them. تفاصيل المقالة -
حرية الوصول المقاله
6 - Inactivation of Fecal coliforms during solar and photocatalytic disinfection by zinc oxide (ZnO) nanoparticles in compound parabolic concentrators (CPCs)
Ahmadreza Yazdanbakhsh Kourosh Rahmani Hasan Rahmani Mansour Sarafraz Masoumeh Tahmasebizadeh Ayat RahmaniWater samples of 0, 50, and 100 nephelometric turbidity units (NTU) spiked with fecal coliforms (107 CFU/ml) were exposed to natural sunshine in 1l quartz glass tubes fitted with rectors’ compound parabolic concentrators CPCS at two forms CPC1 (whit nanoparticle z أکثرWater samples of 0, 50, and 100 nephelometric turbidity units (NTU) spiked with fecal coliforms (107 CFU/ml) were exposed to natural sunshine in 1l quartz glass tubes fitted with rectors’ compound parabolic concentrators CPCS at two forms CPC1 (whit nanoparticle zinc oxide) and CPC2(without nanoparticle zinc oxide). The samples were characterized using the X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscope (TEM). On clear days, the complete inactivation times (more than 7-log unit reduction in bacterial population) in the systems with CPC1, and CPC2 were 15, and 30 min, respectively. The maximum temperatures obtained in the water samples were 80 for CPC1, and 82 for CPC2. The use of CPC1 with hydroxyl radicals (OH•) production significantly improved the efficiency of the old CPCS technique, since these systems (CPC1-2) shortened the exposure times to solar radiation and also minimized the negative effects of turbidity and also regrowth was zero in the disinfected samples. Due to two simultaneous effects of high temperatures and UV, regrowth in most ways of solar disinfection was not seen in these examples. Overall, this technology has been proved to be a good enhancement method to inactivate microorganisms under real conditions and represents a good alternative technique to drinking water treatment. تفاصيل المقالة
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