جستجوی مقالات مرتبط با کلیدواژه « Clay » در نشریات گروه « محیط زیست »
تکرار جستجوی کلیدواژه « Clay » در نشریات گروه « علوم پایه »-
Industrial processes are among human activities that cause production of a large volume of wastewater containing organic pollutants such as phenol and its derivatives. Soil remediation is crucial for enhancing environmental quality for both humans and other living organisms. This study investigate the use of an electro-peroxone system to remove environmental pollutants from soil. In conjunction with ozonation, the study employed electrochemically generated hydrogen peroxide using a carbon electrode, addressing concerns about transportation and storage. Experiments were structured using response surface methodology (RSM) with three variables: ozone dosages ranging from 4 to 8 l/h, initial pollutant concentrations from 20 to 50 mg/kg, and treatment durations between 7 and 14 days. The effectiveness of phenol removal from soil was assessed by applying a consistent voltage of 2 V/cm to the soil samples in all experiments. Results revealed a negative correlation between initial pollutant concentration and ozone consumption and a positive correlation between treatment duration and pollutant removal efficiency. Optimal removal efficiency occurred with a 14-day treatment duration, an 8 l/h ozone dosage, and a 20 mg/kg initial pollutant concentration. The electro-peroxone system's application indicates its potential as a sustainable, eco-friendly, and cost-effective approach to soil remediation for pollution.Keywords: Clay, Hydrogen Peroxide, Ozone, Phenol}
-
Pollution, Volume:8 Issue: 4, Autumn 2022, PP 1103 -1115The effect of ceramic filter composition on improving the quality of produced water by reducing total dissolved solids (TDS), barium, and phenol for reverse osmosis (RO) treatment was investigated in the present work. The ceramic filters were fabricated using a residue catalytic cracking (RCC) unit spent catalyst with and without activation, clay, and Dioscorea hispida starch (DHS), at various compositions. The result showed that the optimum removal of TDS, barium, and phenol in produced water was achieved at a flow rate of sample 7 L/min and an operating time of 90 min. Ceramic filter with the composition of 60% spent catalyst without activation: 37.5% clay: 2.5% DHS reduced 34.84% TDS, 27.97% barium, and 71.11% phenol. While, the ceramic filter with a composition of 37.5% activated spent catalyst: 60% clay: 2.5% DHS was removed 51.44% TDS, 27.93% barium, and 85.29% phenol from produced water. The next steps of treatment of filtrates of the ceramic filter using reverse osmosis (RO) membrane showed that the permeate met the Indonesian standard for oil and gas wastewater. In addition, adsorption of TDS, barium, and phenol from produced water was dominated by clay composition in the ceramic filter.Keywords: Adsorption, clay, Dioscorea hispida, Oil reservoirs, spent catalyst}
-
BACKGROUND AND OBJECTIVESBoron is a micronutrient of high importance, both for plant development and normal growth. The range between boron deficiency and toxicity is very narrow, which makes boron unique among the essential micronutrients. Boron adsorption is one of the most important factors determining the release and fixation of this micronutrient, though its adsorption has not been widely studied in semiarid Tunisian soils. This study aims to improve knowledge of B adsorption process in calcareous salt-affected soils in semiarid areas. It equally focuses on the type of cation (monovalent and divalent) in function of the soil texture and time of shaking. These three latter factors influence boron adsorption, which also influence the availability for plants.METHODSA study was carried out on boron adsorption at different shaking time intervals (1, 3, 6 and 9 hours) in two soils of different textures in the absence and presence of different background electrolytes solutions (0.02 N CaCl2, 0.02 N MgCl2 , 0.02 N sodium chloride and 0.02 N potassium chloride.FINDINGSThe soil-A (clay loam) adsorbed more boron than soil-B (sandy loam). Boron adsorption was the highest in Soil-A under the presence of potassium chloride, close to the mean values given when using calcium chloride. In Soil-B, it was found with calcium chloride background electrolyte. Minor boron adsorption was observed in both soils when boric acid solution was used without background electrolytes. Adsorbed boron showed significant differences with the shaking time in all treatments used with background electrolytes solutions, except for boron solution treatment without background electrolyte in both soils. As a comparison of divalent and monovalent cations, boron adsorbed content was higher with the solution containing calcium than in sodium chloride solution, due to the fact that calcium carbonate is an important boron adsorbing surface.CONCLUSIONThis study reveals that the best conditions for maximum boron adsorption are defined by calcium chloride background electrolyte in this type of soil in a determined shaking time interval of 3 hours. This causes a low rate of boron assimilated by plants, which leads to the decrease of the crop yield and the agricultural production, and subsequently hurt the Tunisian national economy.Keywords: Divalent cations, Clay, Monovalent cations, Shaking time, Soil texture, Tunisia}
-
زمینه و هدف
رس های آلی از قرار گرفتن نوعی سورفکتانت کاتیونی در سطح و یا بین لایه های رس طبیعی یا سنتز شده ایجاد و کاربردهای وسیعی دارند. این تحقیق با هدف بررسی مقایسه راندمان جذب و رهاسازی نیترات توسط زیولیت طبیعی ایرانی (سمنان) و نمونه سنتز شده ی خالص وارداتی (Fluka-96096) اصلاح شده صورت گرفته است.
روش بررسیذرات میکرو-زیولیت کلینوپتیلولیت ایرانی و خارجی با استفاده از روش سانتریفیوژ جدا و سپس با استفاده از سورفکتانت هگزادسیل تری متیل آمونیوم بروماید (HDTMA-Br) به میکرو-زیولیت آلی تبدیل شدند. مورفولوژی و ساختار کانی زیولیت مورد مطالعه با استفاده از روش های XRD ، EDX ، SEM و AFM مورد بررسی و شناسایی قرار گرفت. راندمان جذب نیترات در دو سطح سورفکتانت 100و200 درصد گنجایش تبادل کاتیونی بیرونی (ECEC)در سطوح مختلف غلظت اولیه نیترات انجام گرفت. برای بررسی میزان ثبات نیترات جذب شده توسط زیولیت آلی، فرایند رهاسازی در سطح سورفکتانت 200 درصد ECEC در دو غلظت نیترات در زمان های مختلف به صورت فاکتوریل در قالب طرح پایه ی کاملا تصادفی انجام شد.
یافته هاراندمان جذب و پالایش نیترات در سطح سورفکتانت 200 درصد ECEC برای زیولیت های آلی Fluka در غلظت های اولیه 3، 6، 14، 20 و 30 میلی مولار نیترات به ترتیب، 77، 63، 48، 37 و 30 درصد می باشد. در حالی که این راندمان برای میکرو-زیولیت آلی ایرانی به ترتیب، 75، 67، 54، 50 و 33 درصد و اختلاف آن با زیولیت فلوکا در سطح احتمال یک درصد معنی دار نمی باشد. میانگین درصد رهاسازی میکرو-زیولیت آلی ایرانی 21 تا 31 درصد و در میکرو-زیولیت فلوکا 17تا 34 درصد است.
بحث و نتیجه گیریجذب نیترات تحت تاثیر غلظت های اولیه نیترات و سطوح متفاوت سورفکتانت قرار دارد. بهترین سطح سورفکتانت با بالاترین میزان جذب، سطح سورفکتانت 200 درصد ECEC می باشد. نتایج این تحقیق نشان داد که میکرو-زیولیت فلوکا نه تنها برتری قابل توجهی نسبت به زیولیت طبیعی ایران ندارد، بلکه در برخی موارد نوع ایرانی آن، برتری های اندکی در جذب و رهاسازی نیترات دارد.
کلید واژگان: زئولیت آلی, گنجایش تبادل کاتیونی بیرونی زئولیت, رس}Background and objectiveOrganocalys are modified by cationic surfactant on surface and between layers of natural or synthesis clays and widely are used. The objective of this study were comparison of absorption efficiency and release of nitrate in aqueous solutions by modified Iranian natural zeolite-clinoptilolite (Semnan) and synthesis zeolite of Fluka-96096.
Material and MethodsThe Iranian and Fluka-96096 micro-zeolite (clinoptilolite) was separated by centrifuge method. The micro-zeolites were first modified by hexa-decyltrimethyl-ammonium (HDTMA), a cationic surfactant. Structure and morphology of zeolites were determined XRD, SEM, EDX and AFM. In this study, adsorption efficiency in initial concentrations of nitrate by modified zeolite with surfactant loading of 100 and 200% external cation exchange capacity (ECEC) was investigated in a completely randomized factorial design. The nitrate release as affected by time at 4 and 14 mM of nitrate in surfactant loading 200% ECEC were also evaluated.
ResultsThe results showed that absorption efficiency of nitrate by Fluka micro-organozeolite with surfactant loading of 200% ECEC in 3, 6, 20 and 30 mM nitrate were 77, 63, 48, 37 and 30% respectively, whereas, by Iranian micro-organ zeolite were 75, 67, 54, 50 and 33% respectively and no significant together (p≤0.01). The mean of nitrate release were 31 to 21%, in Iranian micro-organ zeolite, whereas for Fluka micro-organ zeolite were 17 to 34%.
Discussion and ConclusionThe adsorption efficiency of nitrate was significant by initial nitrate concentration and surfactant’s level. The best adsorption efficiency of nitrate occurred at 200% of ECEC. The results of this research showed that the micro-organ zeolite of Fluka-96096 not only is not better than Iranian micro-zeolite, but also, Iranian micro-organ zeolite have been better for nitrate absorption and release in some cases.
Keywords: Organ Zeolite, External Cation exchange Capacity of Zeolite, Clay} -
In this study, removal of methylene blue (MB) and maxilon blue SL 200% (MB SL) dyes from aqueous solutions by using raw clay (RC) of Nevsehir (Turkey) vicinity and ultrasonic-acid modified clay (MC) was investigated. Adsorption was carried out with 500 mg/L MB and 50 mg/L for MB SL in terms of different adsorbent dosages, contact time, solution pH, temperature and stirring speed. The fitting of adsorption process with respect to Freundlich and Langmuir isotherms was examined. In this study, it was determined that the experimental data for MB dye removal by using RC (R2= 0.9737, Qo=3333 mg/g) and MC (R2=0.9914, Qo=5000 mg/g) were well fitted to Langmuir isotherm model. In addition to this, the experimental data for the removal of MB SL dye by using RC (R2= 0.9104, KF =19.45 mg/g) and MC (R2=0.9933, KF =44.62 mg/g) were well fitted to Freundlich isotherm model. As a result; it was indicated that raw clay can be used for the removal of cationic MB and MB SL dyes and ultrasonic-acid modified clay has high adsorption capacity for both of the dyes. Low-cost clay can be used for the removal of MB and MB SL dyes in preference to other adsorbents. Ultrasonic-acid modification was found as an alternative significant method for adsorbent modification.Keywords: Adsorption, Clay, Dye, Ultrasonic, acid modification}
-
The aims of the current research were determination of the carbon sequestration in three soils types with different plant coverage in Gazvin and Zanjan provinces. One of the studied sites was located in Gazvin province with slaine soils. This site was covered with plants for slaine soils. The second site was located in Zanjan province with gypsic soils. This site was covered with plants for gypsic soils. The third site also was located in calcie soils of Zanjan province. This site was under barley cultivation. The sequestrated carbon was studied in 2 layers of each soil profile including 0-30 and 0-100 cm and the distribution ofthe organic carbon were mapped by GIS software. The results showed that the total soil organic carbon was significantly different among the locations. Total carbon stores of 0-30 cm for the first, second and third locations were 279, 303 and 220 ton/ha, and carbon stores of 0-100 cm for the first, second and third locations were 486, 320 and 602 ton/ha, respectively.Keywords: Carbon sequestration, GIS, Plant, Electrical conductivity, Clay}
-
This study reports the adsorption of crystal violet (CV) cationic dye on natural clay originated from Agadir region (south Morocco) through batch adsorption experiment, in order to develop a low-cost, natural, eco-friendly and alternative adsorbent for the removal of organic pollutants. Several analytical techniques (XRD, BET, TDA, TGA and FTIR) were used to characterize the studied material. The effect of different parameters were studied such as pH (3–10), adsorbent mass (0.02- 0.3 g), contact time (20–120 min), initial dye concentration (100–900 mg/L), and temperature (25– 65 °C) on the adsorption of CV dye. The results Showed That CV adsorption on the natural clay depends on pH, initial dye concentration and temperature. The adsorption equilibrium data were fitted in Langmuir, Freundlich and Timken adsorption isotherm models. The adsorption data obtained were well described by Langmuir isotherm model with correlation coefficients (2 =0.99). Maximum adsorption capacity of clay was found to be 250 mg/g. Adsorption kinetics were well fitted by Pseudo-second order kinetic model (R2= 0.999). Thermodynamic study revealed that the adsorption of CV on clay is spontaneous physical sorption process, endothermic and favorable. Experimental results indicate that the clay studied is a promising adsorbent for the removal of cationic dye molecules from aqueous solutions.Keywords: Adsorption, Clay, Dye, Kinetic, Isotherm models, Thermal Analysis}
-
The aim of this study was to examine the potential of clay material for the elimination of excess fluoride from groundwater. This study is based on empirical laboratory research. The Natural clay material was gathered and dried in an oven at 105ºC for 24 hours. The effect of pH, contact time, adsorbent dose, temperature and adsorbent size was investigated. SEM, FT-IR and XRD were used to characterize the physical attributes (particle size, pore size and distribution, surface roughness) of the natural clay material. The removal efficiency of clay material was augmented by raising the adsorbent dose and contact time, and decreasing the initial concentration of F-. At low pH (pH=2), the maximum amount of fluoride adsorbed by the clay material (F-= 1.0 mg/L). The amount of fluoride adsorbed increased from 1.0 to 1.6 mg/L, (C0=2.3 mg/L) with the maximum temperature of 343K. This seems to be the mechanism is endothermic in nature. The results indicated that clay material can be successfully used as an effective adsorbent for F- removal. We concluded that clay material can be a cheap, efficient, and environmental friendly adsorbent of F- from aqueous solutions.Keywords: Clay, Fluoride, Groundwater, Adsorbent dose}
-
هدف از بررسی مواد در مقیاس نانو، یافتن طبقه جدیدی از مصالح با عملکردهای نوین است، که آن ها را می توان به عنوان مصالحی با عملکرد ویژه و چندمنظوره بیان نمود. با توجه به تحقیقات وسیعی که در سالهای اخیر در موضوع اندرکنش خاک و آلودگی صورت گرفته است در زمینه فرایند اندرکنش آلاینده های فلز سنگین و نانورسها تحقیقات قابل توجهی انجام نشده است. آلاینده فلز سنگین مس، به عنوان یکی از آلاینده های فلز سنگین متداول در پروژه های ژئوتکنیک زیست محیطی شناخته شده است. بر این اساس هدف این پژوهش مطالعه رفتار ژئوتکنیک زیست محیطی نانورس ها و نانورس های اصلاح شده با کربنات از نظر قابلیت جذب آلاینده فلز سنگین مس بوده است. برای دستیابی به این هدف، با انجام یک سری آزمایش های ژئوتکنیک زیست محیطی، فرایند اندرکنش نانورس و آلاینده فلز مس مطالعه شده است. بررسی ظرفیت بافرینگ و میزان نگه داری فلز مس به وسیله نانورس های اصلاح شده در حضور کربنات نشان میدهد که بخش قابل توجهی از ظرفیت بافرینگ و قابلیت خاک در نگه داری آلاینده، ناشی از حضور کربنات است. نتایج تحقیق حاضر بیان گر آن است که در نمونه های بنتونیت، کائولینیت و چهار نانورس کلوزایت، ترتیب قابلیت نگه داری آلودگی به صورت ذیل بوده است:Bentonite > Cloisite®Na+ > Kaolinite > Cloisite®30B > Cloisite®20A > Cloisite®15A لیکن با افزایش درصد کربنات ترتیب قابلیت نگه داری آلاینده توسط نمونه های رسی فوق تغییر می کند. هنگامی که نمونه های نانورس با 8% کربنات اصلاح می شوند، ترتیب قابلیت نگه داری آلودگی فلز سنگین مس توسط نمونه ها به صورت ذیل بوده است:
کلید واژگان: نانورس, کربنات, فلز سنگین مس, ظرفیت بافرینگ}The main objective to study the materials in nano scale is establishing the new classification of materials and their new function which may introduce a noticeable application for them. Even though there have been several researches on the process of soil-contaminant interactions, the process of heavy metal contaminant and nano-clays have not been investigated yet. On the other hand, contamination of soils with Cu ions is very common in geo-environmental projects. The main objective of this research is to investigate the interaction process of Cu contaminant with nano-clays before and after treatment with carbonate. To achieve this objective, series of geo environmental experiments were performed. These experiments included, batch equilibrium testing, buffering and pH measurements. The achieved results indicate that the main part of buffering capacity and contaminant retention of soil are due to the presence of carbonate in soils. According to the achieved results in betonies, kaolinite, and four nano-clay samples the contaminant retention of soils is as follows: Betonies > Cloisite®Na+ > Kaolinite > Cloisite®30B > Cloisite®20A > Cloisite®15A. Furthermore, with increasing of carbonate content there will be a change on the order of ability of samples for contaminant retention. For soil samples with 8% carbonate, the Cu retention of samples will be according to the following order:Cloisite®Na+ > Cloisite®15A ≥ Cloisite®20A > Cloisite®30B > Bentonite
Keywords: Nano, clay, Carbonate, Buffering capacity, Heavy metal contaminant} -
An organophilic clay-based adsorbent was prepared by incorporating a cationic surfactant,hexadecyltrimethylammonium (HDTMA) at different levels of CEC in Tunisian smectite-illite clay. The presence of the HDTMA surfactant enhanced the adsorption ability of the clays toward plyphenolic compounds from aqueous systems. Adsorption experiments were carried out using a batch equilibration technique to investigate the removal of tannin by the surfactant modified clay. Adsorbent characterizations were investigated using X-ray diffraction, infrared spectroscopy, surface area analysis, and potentiometric titration. The effects of pH, contact time and initial solute concentration on the adsorption of tannin onto modified clay were investigated. The adsorption process was much dependent on the pH and was found to follow pseudosecond- order kinetics. The optimum pH value was at pH ranging from 4.5 to 6. The maximum removal efficiency of tannin from aqueous solution was 91%. The adsorption isotherms were measured and correlated to Langmuir isotherms. From the results it can be concluded that the surfactant-modified clay could be a good adsorbent for treating tannin-contaminated waters.Keywords: Clay, HDTMA, Tannin, Adsorption, Langmuir isotherm}
- نتایج بر اساس تاریخ انتشار مرتب شدهاند.
- کلیدواژه مورد نظر شما تنها در فیلد کلیدواژگان مقالات جستجو شدهاست. به منظور حذف نتایج غیر مرتبط، جستجو تنها در مقالات مجلاتی انجام شده که با مجله ماخذ هم موضوع هستند.
- در صورتی که میخواهید جستجو را در همه موضوعات و با شرایط دیگر تکرار کنید به صفحه جستجوی پیشرفته مجلات مراجعه کنید.
©2000-2024 magiran.com All Rights Reserved.