Using Ash Prepared from Almond Shell for Removing Acid Red 18 from Aqueous Solutions

زمینه و هدف: رنگ اسید رد 18 یکی از پر مصرف ترین رنگ در صنایع نساجی به شمار می روند که افزایش خطرات زیست محیطی را به دنبال دارند. بنابراین لازم است که پساب صنایع نساجی قبل از تخلیه به محیط با استفاده از روش های موثر مورد تصفیه قرار گیرند. هدف از این مطالعه، ارزیابی حذف رنگ اسید رد 18 از محلول های آبی با استفاده از خاکستر تهیه شده از پوسته بادام می باشد. روش بررسی: در این مطالعه تجربی از اسید رد 18 به عنوان نماینده رنگ های آزو استفاده شد. پوسته بادام به روش حرارتی فعال شد (تهیه خاکستر) و در یک سیستم منقطع برای حذف رنگ از محلول های آبی به کار گرفته شد. عملیات آزمایشگاهی در شرایط: pH (12-2)، زمان تماس (120-15 دقیقه)، مقدار جاذب (2-2/0 گرم بر لیتر)، غلظت اولیه رنگ (100-25 میلی گرم بر لیتر) و دمای آزمایشگاهی (Cº 1±25) انجام شد. یافته ها: نتایج نشان داد که بیشترین میزان حذف اسید رد 18 (90) به وسیله خاکستر تهیه شده از پوسته بادام در 2=pH، زمان تماس 60 دقیقه و دوز جاذب 6/1 گرم بر لیتر به دست می آید. همچنین داده های تعادل با مدل های ایزوترم لانگمویر و فروندلیچ تطبیق داده شد که حاصل امر نشانگر تطابق بهتر داده های حاصل از مطالعه حاضر با مدل جذب لانگمیر (0/9782=R2) نسبت به معادله جذب فروندلیچ (0/9579=R2) می باشد. نتیجه گیری: مطالعه حاضر نشان داد که فعال سازی حرارتی پوسته بادام و کاربرد آن در شرایط کنترل شده، روش موثری در حذف رنگ های آزو از پساب های نساجی می باشد

The study of enhanced coagulation process efficacy and direct filtration’s effectiveness on elimination of natural organic materials from surface waters

زمینه و هدف: یکی از مشکلات اصلی استفاده از منابع آب های سطحی، غلظت بالای مواد آلی طبیعی آن است. مواد آلی طبیعی پیش ساز محصولات جانبی گندزدایی بوده و برخی از این مواد می توانند برای انسان سمی یا سرطان زا باشند. هدف از این مطالعه بررسی کارآیی فرآیند انعقاد پیشرفته و فیلتراسیون مستقیم برای حذف مواد آلی طبیعی از آب های سطحی بود. روش بررسی: در این مطالعه نیمه تجربی، پایلوت برای انعقاد پیشرفته با فیلتراسیون مستقیم با ظرفیت 144 لیتر بر ساعت طراحی شد. تالاب چغاخور واقع در 65 کیلومتری شهرکرد به عنوان محل نمونه برداری انتخاب و نمونه ها برداشت شد. جهت سنجش مواد آلی طبیعی (NOMs) از روش جذب UV در طول موج 254 نانومتر بوسیله دستگاه اسپکتروفتومتر استفاده شد. در این پژوهش تأثیر pH، دوز منعقد کننده کلروفریک (FeCl3) و دبی ورودی به سیستم بر حذف مواد آلی طبیعی مورد بررسی قرار گرفت. یافته ها: نتایج نشان داد که در شرایط بهینه میزان حذف NOMs حدود 94 درصد بود و مقدار باقیمانده آلاینده به کمتر از mg/l 2 رسید. شرایط بهینه برای حذف مواد آلی طبیعی در pH 2/6، دوز کلروفریک mg/l 60 و دبی l/h 95 اتفاق افتاد. بر اساس تحلیل اثر عوامل مورد بررسی، غلظت ماده منعقد کننده بیشترین اثر را بر راندمان حذف NOMs داشته و به ترتیب pH و دبی در رتبه های بعدی قرار داشتند. نتیجه گیری: طبق نتایج بدست آمده، انعقاد پیشرفته بوسیله کلروفریک با فیلتراسیون مستقیم می تواند بازدهی حذف مواد آلی طبیعی در تصفیه خانه آب را بهبود دهد

Study of the effectiveness of the third generation polyamideamine and polypropylene imine dendrimers in removal of reactive blue 19 dye from aqueous solutions

Background: Dye and colored materials cause health risks in water and therefore, must be removed from water supplies and wastewater. The aim of this study was to evaluate the effectiveness of the third generation poly(amidoamine) (PAMAM) and poly (propylene imine) dendrimers (PPI-G3) in the removal of reactive blue 19 (RB19) dye from aqueous solutions and determine the optimum conditions for the removal. Methods: This study was performed in a laboratory and batch scale. In this study, synthetic wastewater was examined with three different concentrations of RB19 (25, 50, and 100 mg/L), different pHs (3, 7, and 10), various amounts of dendrimer (0.4, 0.8, 1.2, and 1.6 g/L), and at different times (15, 30, and 60 minutes) during the adsorption process. The remaining amount of dye was measured by spectrophotometer at 592 nm wavelength. Langmuir and Freundlich isotherms were also tested. Results: The results showed that by increasing the reaction time and adsorbent dosage, the rate of dye removal increased while by increasing the initial dye concentration and pH, the dye removal efficiency was significantly decreased. In this study, with increase of pH from 3 to 10, dye removal efficiency at a concentration of 25 mg/L, decreased from 72% to 20% and 88% to 17% by PAMAM and PPI dendrimers, respectively. Excel software was used for data analysis. Conclusion: Both adsorbents had a good dye removal efficiency, but PPI dendrimer was more effective in removing RB19. Adsorption data followed the Langmuir isotherm. Keywords: Adsorption, Wastewater, Dendrimer, Polyamide amine, Polypropylene imin

The use of chitin shrimp shells for the biosorption of zinc from aqueous solutions

The removal of zinc ions from aqueous solutions on the chitin extracted of shrimp shells has been studied by using batch adsorption method. Experiments were performed as a function of initial pH (3-7), initial metal concentration (50-500mg/l), and adsorbent dose (0/5-10 gr) at 25°C. .The equilibrium metal uptake was increased and percentage biosorption was decreased with an increase in the initial concentration. So, the data showed that optimum pH for efficient biosorption of zinc by chitin was 7. The pseudo first order and pseudo second order kinetic models were used to describe the kinetic data. The dynamic data fitted with the pseudo second order kinetic model for zinc. So, Experimental data obtained were tested with the adsorption models like Langmuir and Freundlich models and Biosorption isothermal data were well correspond by Freundlich model. So that chitin extracted of shrimp shells relatively high sorption capacity, when comparing with other sorbents that was evaluated as 270.270 mg/g

Physicochemical Characterization of Biopolymer Chitosan Extracted from Shrimp Shells

Chitosan is a deacetylated derivative of chitin, which is a naturally abundant mucopolysaccharide, supporting the matter of crustaceans, insects, and fungi. Because of its unique properties, such as non-toxicity, biodegradability, and biocompatibility, chitosan has a wide range of applications in various fields. The objective of the present work is to extract the polymer chitosan from Persian Gulf shrimp shells. In order to determine the physicochemical characteristics of the extracted chitosan, degree of deacetylation, molecular weight, water and fat binding capacities extraction rate, and apparent viscosity were measured using a variety of techniques including viscometry, weight measurement method and Fourier transform infrared spectroscopy (FTIR). The results of the study of the physicochemical properties, molecular weight (6.7×105 Da), degree of deacetylation (57%), ash content as well as yield (0.5%) of the prepared chitosan indicated that shrimp processing wastes (shrimp shells) are a good source of chitosan. The water binding capacity (521%) and fat binding capacity (327%) of the prepared chitosan are in good agreement with the other studies. The elemental analysis showed the C, H and N contents of 35.92%, 7.02%, and 8.66%, respectively. In this study, the antimicrobial activity of chitosan was evaluated against Staphylococcus aureus and Escherichia coli. The results indicated the high potential of chitosan as an antibacterial agent. Moreover, the results of the study indicated that shrimp shells are a rich source of chitin as 25.21% of the shell’s dry weight

Study of the effectiveness of the third generation polyamideamine and polypropylene imine dendrimers in removal of reactive blue 19 dye from aqueous solutions

Background: Dye and colored materials cause health risks in water and therefore, must be removed from water supplies and wastewater. The aim of this study was to evaluate the effectiveness of the third generation poly(amidoamine) (PAMAM) and poly (propylene imine) dendrimers (PPI-G3) in the removal of reactive blue 19 (RB19) dye from aqueous solutions and determine the optimum conditions for the removal. Methods: This study was performed in a laboratory and batch scale. In this study, synthetic wastewater was examined with three different concentrations of RB19 (25, 50, and 100 mg/L), different pHs (3, 7, and 10), various amounts of dendrimer (0.4, 0.8, 1.2, and 1.6 g/L), and at different times (15, 30, and 60 minutes) during the adsorption process. The remaining amount of dye was measured by spectrophotometer at 592 nm wavelength. Langmuir and Freundlich isotherms were also tested. Results: The results showed that by increasing the reaction time and adsorbent dosage, the rate of dye removal increased while by increasing the initial dye concentration and pH, the dye removal efficiency was significantly decreased. In this study, with increase of pH from 3 to 10, dye removal efficiency at a concentration of 25 mg/L, decreased from 72% to 20% and 88% to 17% by PAMAM and PPI dendrimers, respectively. Excel software was used for data analysis. Conclusion: Both adsorbents had a good dye removal efficiency, but PPI dendrimer was more effective in removing RB19. Adsorption data followed the Langmuir isotherm

Synthesis of a Doped α-Fe₂O₃/g-C₃N₄ Catalyst for High-Efficiency Degradation of Diazinon Contaminant from Liquid Wastes

In this work, a hematite/porous graphite carbon-nitride (α-Fe2O3/g-C3N4) catalyst was synthesized through the doping of hematite loaded onto porous graphite carbon-nitride using a heat treatment process. Then, the ability of catalyst was evaluated to degrade diazinon (DZN) for the first time, mainly via the sonophotocatalytic process. Among the samples, the greatest DZN degradation was observed in the sonophotocatalytic system, which separated 100% of DZN from the aqueous solution after 50 min, while the removal percentages for the sonocatalytic, photocatalytic, and adsorption systems were 72.9, 89.1, and 58.1%, respectively. The results of scavengers showed that both sulfate and hydroxyl radicals (•OH) participated in removing DZN, although positive holes and negative •OH played a major role. Moreover, the removal efficiencies of the target pollutant using the sonophotocatalytic process were higher than those using the photocatalytic, sonocatalytic, and adsorption processes. The reaction profile followed pseudo-first-order kinetics, and the reaction rate coefficient for the sonophotocatalytic system was 2.2 times higher than that of the photocatalytic system and 2.64 times higher than that of the sonocatalytic system. The energy consumption of the sonophotocatalytic system after 60 min was 11.6 kWh/m3, while it was 31.1 kWh/m3 for the photocatalytic system. A DZN removal percentage of 100% was obtained after 50 min under the following conditions: UV intensity of 36 watts, ultrasound frequency of 36 kHz, DZN concentration of 50 mg/L at pH 5, and α-Fe2O3/g-C3N4 dosage of 0.4 g/L. The catalyst reusability was examined with only a 9.9% reduction in efficiency after eight consecutive cycles. The chemical oxygen demand (COD) and total organic compound (TOC) removal percentages were 95.6% and 88.6%, respectively, and the five-day biochemical oxygen demand (BOD5)/COD ratio was 0.16 at the beginning of the degradation process and 0.69 at the end of the process. In addition, toxicological experiments showed that degradation of DZN by the sonophotocatalytic process exhibited low toxicity. All results confirmed that the sonophotocatalytic process using α-Fe2O3/g-C3N4 was a highly efficient process for DZN pollutant removal from liquid wastes

Synthesis of a Doped α-Fe2O3/g-C3N4 Catalyst for High-Efficiency Degradation of Diazinon Contaminant from Liquid Wastes

In this work, a hematite/porous graphite carbon-nitride (α-Fe2O3/g-C3N4) catalyst was synthesized through the doping of hematite loaded onto porous graphite carbon-nitride using a heat treatment process. Then, the ability of catalyst was evaluated to degrade diazinon (DZN) for the first time, mainly via the sonophotocatalytic process. Among the samples, the greatest DZN degradation was observed in the sonophotocatalytic system, which separated 100% of DZN from the aqueous solution after 50 min, while the removal percentages for the sonocatalytic, photocatalytic, and adsorption systems were 72.9, 89.1, and 58.1%, respectively. The results of scavengers showed that both sulfate and hydroxyl radicals (•OH) participated in removing DZN, although positive holes and negative •OH played a major role. Moreover, the removal efficiencies of the target pollutant using the sonophotocatalytic process were higher than those using the photocatalytic, sonocatalytic, and adsorption processes. The reaction profile followed pseudo-first-order kinetics, and the reaction rate coefficient for the sonophotocatalytic system was 2.2 times higher than that of the photocatalytic system and 2.64 times higher than that of the sonocatalytic system. The energy consumption of the sonophotocatalytic system after 60 min was 11.6 kWh/m3, while it was 31.1 kWh/m3 for the photocatalytic system. A DZN removal percentage of 100% was obtained after 50 min under the following conditions: UV intensity of 36 watts, ultrasound frequency of 36 kHz, DZN concentration of 50 mg/L at pH 5, and α-Fe2O3/g-C3N4 dosage of 0.4 g/L. The catalyst reusability was examined with only a 9.9% reduction in efficiency after eight consecutive cycles. The chemical oxygen demand (COD) and total organic compound (TOC) removal percentages were 95.6% and 88.6%, respectively, and the five-day biochemical oxygen demand (BOD5)/COD ratio was 0.16 at the beginning of the degradation process and 0.69 at the end of the process. In addition, toxicological experiments showed that degradation of DZN by the sonophotocatalytic process exhibited low toxicity. All results confirmed that the sonophotocatalytic process using α-Fe2O3/g-C3N4 was a highly efficient process for DZN pollutant removal from liquid wastes

Determining the relationship between health literacy level and quality of life among the elderly living in nursing homes

BACKGROUND: The literacy level of the elderly is predictive of health behaviors, average hospitalization in health centers, and the type of verbal interaction with health service providers; as the level of literacy changes, the quality of life may also change. This study aimed to determine the relationship between health literacy level and quality of life among the elderly living in nursing homes in 2018-2019. MATERIALS AND METHODS: This study was of a descriptive-analytic, correlation type that was performed on 175 elderly of selected nursing homes in Tehran. The research tools included the Abbreviated Mental Test; Control, Autonomy, Pleasure and Self-realization questionnaire-19; and Health Literacy of Iranian Adults Questionnaire (HELIA). Data were analyzed using descriptive and inferential statistics by SPSS 22 software. RESULTS: The total score of health literacy and the quality of life of the elderly was 51.01 and 47.75, respectively. The literacy of most of the studied samples was 'inadequate' and 'not much adequate' (0-66). The relationship between health literacy and quality of life in the elderly was significant, and there was a direct and statistically significant relationship between them (P = 0.003). That is, by an increase in literacy rates, the scores of quality of life of elderly people were also increased. The correlation was equal to r =-0.28. Health literacy has the ability (31.98%) to predict the quality of life. CONCLUSION: The results showed a lack of enough education literacy, the average quality of life, and the existence of a significant relationship between health literacy and quality of life in the elderly. The wide range of inadequate literacy in the elderly reveals the importance of paying more attention to the issue of literacy in health planning and health promotion at the national and local levels