-
حرية الوصول المقاله
1 - The generalized second law of thermodynamics in f(R) gravity for various choices of scale factor
Rahul Ghosh Surajit ChattopadhyayAbstractThe present study is aimed at investigating the validity of the generalized second law (GSL) of thermodynamics in f(R) gravity. Choosing f(R)=R+ξRμ+ζR−ν with ξ,μ,ζ, ν > 0 (following the study of Nojiri and Odintsov in 2003), we have computed the time derivatives أکثرAbstractThe present study is aimed at investigating the validity of the generalized second law (GSL) of thermodynamics in f(R) gravity. Choosing f(R)=R+ξRμ+ζR−ν with ξ,μ,ζ, ν > 0 (following the study of Nojiri and Odintsov in 2003), we have computed the time derivatives of total entropy for various choices of scale factor pertaining to emergent, intermediate, and logamediate scenarios of the universe. We have taken into account the radii of Hubble, apparent, particle, and event horizons while computing the time derivatives of entropy under various situations being considered. After analyzing through the plots of time derivative of total entropy against cosmic time, it is observed that the derivative always stays at positive level. This indicates the validity of GSL of thermodynamics in the f(R) gravity irrespective of the choices of scale factor and enveloping horizon. تفاصيل المقالة -
حرية الوصول المقاله
2 - Thermodynamics of charged rotating solutions in Brans–Dicke gravity with Born–Infeld field
J. Pakravan M. V. TakookAbstractWe derive new exact charged rotating solutions of (n+1)documentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} egin أکثرAbstractWe derive new exact charged rotating solutions of (n+1)documentclass[12pt]{minimal} usepackage{amsmath} usepackage{wasysym} usepackage{amsfonts} usepackage{amssymb} usepackage{amsbsy} usepackage{mathrsfs} usepackage{upgreek} setlength{oddsidemargin}{-69pt} egin{document}$$(n+1)$$end{document}-dimensional Brans–Dicke theory in the presence of Born–Infeld field and investigated their properties. Because of the coupling between scalar field and curvature, the field equations cannot to be solved directly. Using a new conformal transformation, which transforms the Einstein-dilaton–Born–Infeld gravity Lagrangian to the Brans–Dicke–Born–Infeld gravity one, the field equations are solved. We also compute temperature, charge, mass, electric potential, and entropy; entropy, however, does not obey the area law. These quantities are invariant under conformal transformation and satisfy the first law of thermodynamics. تفاصيل المقالة -
حرية الوصول المقاله
3 - Removal of Basic Dye Bromophenol Blue from aqueous solution by Electrocoagulation using Al – Fe Electrodes: Kinetics, Equilibrium and Thermodynamics Studies.
Abideen Adeogun B BabuElectrocoagulation (EC) in a batch cell with Al anode and Fe cathode in monopolar parallel (MP) connection was used for the removal of basic dye, Bromophenol Blue (BPB). The effects of current density, pH, temperature and initial dye concentration, on the process were i أکثرElectrocoagulation (EC) in a batch cell with Al anode and Fe cathode in monopolar parallel (MP) connection was used for the removal of basic dye, Bromophenol Blue (BPB). The effects of current density, pH, temperature and initial dye concentration, on the process were investigated. Equlibrium data were analyzed using four model equations: Langmuir, Freudlinch, Temkin and DubininRadushkevich. Data obtained from the time dependent electrocoagulation removal of BPB were analyzed with pseudo-first-order, pseudo-second-order and Elovic kinetic models. The study showed that the process depend on current density, temperature, pH and initial dye concentration. The process attained equilibrium after 15 minutes at 30 oC, all the isotherm models fitted the data with R2 > 0.9. The maximum removal capacity Qm value of 166.50 mg g-1 was obtained for the study while the first order kinetic model best described the process based on the lower values of %SSE. The calculated thermodynamics parameters (∆Go, ∆Ho and ∆So) indicated that the process is spontaneous and endothermic in nature. تفاصيل المقالة -
حرية الوصول المقاله
4 - Thermodynamic study of lead ion removal by adsorption onto nanographene sheets
Y. Saghapour M. Aghaie K. ZareA batch adsorption study was applied to investigate the adsorption of Pb2+ ions from aqueous solutionby nanographene (nG).The adsorption percentage of Pb2+ions onto nG samples at different initial pH,contact time (tc), adsorbent dosage (mnG) and temperature (T) were inv أکثرA batch adsorption study was applied to investigate the adsorption of Pb2+ ions from aqueous solutionby nanographene (nG).The adsorption percentage of Pb2+ions onto nG samples at different initial pH,contact time (tc), adsorbent dosage (mnG) and temperature (T) were investigated. The results showedthat nG is an excellent adsorbent for Pb2+ions removal from aqueous solutions with an adsorptionpercentage of up to 79.8% at initial Pb2+concentration of 20ppm and temperature of 298K.Theexperimental data could be well described by the Freundlich and Langmuire isotherm model;thermodynamic parameters of adsorption process (AG0, AH0, ASo) were also evaluated. The overalladsorption process was exothermic and spontaneous in nature .The results indicate that Pb2+ionsadsorption onto nG may be chemisorption. تفاصيل المقالة -
حرية الوصول المقاله
5 - Theoretical study of 2,3,7,8-tetrachlorodibenzo-para-dioxine removal by boron nitride-nanotube (BNNT): QSAR, IR-DFT
L. MahdavianThe study examined corrosion inhibition of corrosion inhibition of 5-methyl-2H-imidazol-4-carboxaldehyde and 1H-Indole-3-carboxaldehyde on mild steel in acidic medium using weight loss and Density Functional Theory (DFT) methods. DFT calculations were carried out at B3L أکثرThe study examined corrosion inhibition of corrosion inhibition of 5-methyl-2H-imidazol-4-carboxaldehyde and 1H-Indole-3-carboxaldehyde on mild steel in acidic medium using weight loss and Density Functional Theory (DFT) methods. DFT calculations were carried out at B3LYP/6-31+G** level of theory in aqueous medium on the molecular structures to describe electronic parameters. The values of thermodynamic parameters such as free energy of adsorption (ΔGºads), adsorption equilibrium constant (Kads), adsorption entropy (ΔSºads), adsorption enthalpy (ΔHºads) and activation energy (Ea) were calculated, analyzed and discussed. The adsorption process on mild steel surface showed that 4-methylimidazol-5-carboxaldehyde and Indole-3-carboxaldehyde obeyed Freundlich and Temkin adsorption isotherms respectively. Also, the molecular parameters associated with inhibition efficiency such as EHOMO, ELUMO, band gap energy (ELUMO- EHOMO), softness (S), electron affinity (EA) and number of electrons transfer were calculated. The higher inhibitory property of 5-methyl-2H-imidazol-4-carboxaldehyde was attributed to the presence of higher number of protonation sites as a result of higher number of nitrogen atoms, increase in number of plane protonated species and higher net charges on the ring atoms. تفاصيل المقالة -
حرية الوصول المقاله
6 - Thermodynamic Study of Hg(II) Ion Adsorption onto Nano Hydroxyapatite from Aqueous Solution
S. Ghasemlou H. Aghaie M. MonajjemiHydroxyapatite nanocrystals were synthesized by sol-gel combustion method for the sorption ofHg(II) ions from aqueous solutions. The effects of varying parameters such as pH, temperature, initialmetal concentration, and contact time on the adsorption process were examin أکثرHydroxyapatite nanocrystals were synthesized by sol-gel combustion method for the sorption ofHg(II) ions from aqueous solutions. The effects of varying parameters such as pH, temperature, initialmetal concentration, and contact time on the adsorption process were examined. Adsorptionequilibrium was established in 360 minutes and the maximum adsorption of Hg(II) on thehydroxyapatite was observed to occur at pH 7.0. The adsorption data correlated with Freundlich andLangmuir isotherms. The Langmuir isotherm showed a better fit to the equilibrium data. Theadsorption thermodynamic parameters (ΔG 0, Δ H 0, and Δ S 0) were calculated which showed anendothermic adsorption process. The equilibrium parameter (RL) indicated that hydroxyapatitenanocrystals are useful for Hg(II) removal from aqueous solutions. تفاصيل المقالة -
حرية الوصول المقاله
7 - نقد و بررسی دیدگاه های اصلی رقیب در مورد مسأله ی بازگشت پذیری
سید رضا ملیح زهرا شجاعیبا کشف قانون دوم ترمودینامیک و تلاش برای ابتنای آن بر دینامیک کلاسیک در نیمه دوم قرننوزدهم میلادی، مسأله یا پارادوکس بازگشت پذیری برای اولین بار مطرح شد، زیرا قوانین دینامیککلاسیک برخلاف قانون دوم ترمودینامیک نسبت به زمان متقارن یا بازگش تپذیر بودند. در این مقالهپس از ش أکثربا کشف قانون دوم ترمودینامیک و تلاش برای ابتنای آن بر دینامیک کلاسیک در نیمه دوم قرننوزدهم میلادی، مسأله یا پارادوکس بازگشت پذیری برای اولین بار مطرح شد، زیرا قوانین دینامیککلاسیک برخلاف قانون دوم ترمودینامیک نسبت به زمان متقارن یا بازگش تپذیر بودند. در این مقالهپس از شرح این مسأله به بیان دو رهیافت اصلی در حل این مسأله می پردازیم. در اولین دیدگاه کهپریگوژین از سردمداران آن است، بازگشت ناپذیری ناشی از ناپایدار یهای دینامیکی دانسته می شود وتعریف می شود؛ در حال یکه در دیدگاه بی نظمی این ویژگی در سطح میکروسکوپی در قالب نوعیدیگر، افرادی مانند پرایس و بریکمان بازگشت ناپذیری در سطح ماکروسکوپی را ناشی از وجودشرایط اولیه ی خاصی برای جهان در نظر م یگیرند و برقراری بازگش تپذیری در سطح میکروسکوپیرا در تضاد با آن نم یدانند. با وجود تفاوت این دو دیدگاه در مبانی نظری، نشان خواهیم داد کهمی توان این نتیجه ی مشترک را از آنها استخراج کرد که بازگشت پذیری اصولاً به لحاظ عملیغیرممکن است. تفاصيل المقالة -
حرية الوصول المقاله
8 - Rice Bran as a Sorbent for Malonic Acid From Aqueous Solution
Narges Samadani Langeroodi Vida Jodaian Sepideh MehraniThe adsorption of malonic acid on the rice bran was studied under various conditions such as temperature, contact time, adsorbent dose and concentration of adsorbate. Batch adsorption experiments were conducted and the result showed that the adsorption was dependent on أکثرThe adsorption of malonic acid on the rice bran was studied under various conditions such as temperature, contact time, adsorbent dose and concentration of adsorbate. Batch adsorption experiments were conducted and the result showed that the adsorption was dependent on all these parameters. The adsorption process obeys the Langmuir and Freundlich adsorption isotherms. The adsorption capacity was found to be 1.24 mg/g. The Sorption of malonic acid on the rice bran was rapid during the first 20 minutes and the equilibrium was found to be attained within 50 minutes. Negative values of Gibbُ s free energy change (ΔG°), show that the adsorption was feasible and spontaneous and negative values of enthalpy change (ΔH°), confirm exothermic adsorption. Adsorption of malonic acid on the rice bran was characterized by Fourier transform infrared (FT-IR) spectroscopy. تفاصيل المقالة -
حرية الوصول المقاله
9 - مطالعه تئوری سینتیک و ترمودینامیک واکنش متوالی هیدروآمیناسیون نوع کوپ و نوآرایی]3و2[ میزنهیمر
میترا صانعی احسان زاهدی سید حسین قربانی احمد سیفهیدروآمیناسیون نوع کوپ نوربورن با استفاده از N-آلیل-N-متیلهیدروکسیلآمین در دمای ℃120 و حلال تتراهیدروفوران منجر به تولید حد واسط ناپایدار دو قطبی N-اکسید شده که پس از نوآرایی]3و2[ میزنهیمر به محصول خنثی با پایداری بالاتر تبدیل میشود. سینتیک و ترمودینامیک این واکنش أکثرهیدروآمیناسیون نوع کوپ نوربورن با استفاده از N-آلیل-N-متیلهیدروکسیلآمین در دمای ℃120 و حلال تتراهیدروفوران منجر به تولید حد واسط ناپایدار دو قطبی N-اکسید شده که پس از نوآرایی]3و2[ میزنهیمر به محصول خنثی با پایداری بالاتر تبدیل میشود. سینتیک و ترمودینامیک این واکنش متوالی در سطح محاسباتی M06-2X/aug-cc-pVTZ مورد مطالعه قرار گرفته است. مرحله اول واکنش گرمازا و غیر خودبخودی است در حالیکه مرحله دوم گرمازا و خودبخودی است. اثرات نامطلوب آنتروپی و دمای بالا باعث میشود که ثابت سرعت مرحله اول، علیرغم پایینتر بودن انرژی فعالسازی، از مرحله دوم کوچکتر بوده و تعادل به سمت تولید حد واسط دو قطبی N-اکسید نباشد. نتایج سینتیکی نشان داد که مرحله رفت هیدروآمیناسیون نوع کوپ مرحله تعیین کننده سرعت بوده، ثابت سرعت کلی واکنش در دمای ℃120 از مرتبه cm3.molecule–1.s–1 27-10 بوده و وابستگی دمایی آن با استفاده از تصحیحات کوانتومی ویگنر و ایکارت بصورت و است. تفاصيل المقالة -
حرية الوصول المقاله
10 - تولید کربن فعال شده از بطریهای PET دورریز و استفاده از آن جهت جذب سطحی آهن (III) از آب
فرخنده اوشال سعید جامه بزرگی مژده لیاقتی دلشاددر این پژوهش ابتدا کربن فعال با استفاده از بطریهای PET دورریز تهیه شد و کربن فعال تهیه شده با استفاده از آنالیزهای FTIR ، BET و SEM شناسایی شد و در ادامه جذب سطحی یونهای فلزی آهن (III) بر روی کربن فعال بررسی شد. اثر متغیرهایی از جمله غلظت اولیه آهن، pH، مقدار جاذب و ز أکثردر این پژوهش ابتدا کربن فعال با استفاده از بطریهای PET دورریز تهیه شد و کربن فعال تهیه شده با استفاده از آنالیزهای FTIR ، BET و SEM شناسایی شد و در ادامه جذب سطحی یونهای فلزی آهن (III) بر روی کربن فعال بررسی شد. اثر متغیرهایی از جمله غلظت اولیه آهن، pH، مقدار جاذب و زمان بررسی شد و نتیجهها نشان داد بهینه مقدار جذب یون آهن در محلول ppm 100 با pH برابر 5 و مدت تماس 60 دقیقه و میزان جاذب 2/0 گرم اتفاق میافتد. ایزوترمها با استفاده از مدلهای ایزوترم لانگمویر، فروندلیچ و تمکین و سینتیکهای جذب با استفاده از مدلهای شبه مرتبه اول و شبه مرتبه دوم مورد مطالعه قرار گرفت و مشاهده شد رفتار فرایند مورد نظر از ایزوترم لانگمویر تبعیت میکند و سینتیک آن بر واکنش شبه مرتبه اول منطبق میشود. تفاصيل المقالة -
حرية الوصول المقاله
11 - مروری بر تحقیقات انجام شده در زمینه تحلیل اکسرژی در بخش های مختلف انرژی
محمد امین صادقی عبدالله خالصی دوستمحدودیت روزافزون منابع انرژی جهان، بعضی ممالک را بر آن داشته است سیاستهای مربوط به انرژی را ارزیابی کرده و روشهایی را برای جلوگیری از اتلاف انرژی بهکارگیرند. در کشورهای در حال توسعه نیز وسایل کممصرف و تکنیکهای جدید برای بهرهبرداری بهتر از منابع محدود انرژی موردتوج أکثرمحدودیت روزافزون منابع انرژی جهان، بعضی ممالک را بر آن داشته است سیاستهای مربوط به انرژی را ارزیابی کرده و روشهایی را برای جلوگیری از اتلاف انرژی بهکارگیرند. در کشورهای در حال توسعه نیز وسایل کممصرف و تکنیکهای جدید برای بهرهبرداری بهتر از منابع محدود انرژی موردتوجه قرارگرفته است. قانون اول ترمودینامیک فقط پایستاری انرژی در هر فرآیند را بیان میکند و حرف دیگری ندارد. ولی قانون دوم باکیفیت انرژی و بهخصوص، با افت کیفیت انرژی در هر فرآیند، با تولید انتروپی و فرصتهای ازدسترفته برای انجام کار، سروکار دارد و امکان بهبود کیفیت را فراهم میآورد. قانون دوم ترمودینامیک وسیله باارزشی برای بهینهسازی سیستمهای پیچیده ترمودینامیکی است. جهت بررسی قابلیت تبدیل به کار پارامتری به نام اکسرژی تعریف میشود. اکسرژی بیشینه یا کمینه انتروپی کار مفید قابل حصول از سیستمی است که در فرآیندی از حالتی به حالت دیگر میرسد.در این تحقیق تلاش بر بررسی پژوهش های پیشین در زمینه بهینه سازی سکتورهای مختلف انرژی است و مطالعات پیشین بررسی شده است. تفاصيل المقالة -
حرية الوصول المقاله
12 - Thermodynamic analysis of nanocrystalline solid solution formation in the W-Co-Si ternary system by mechanical alloying
Majid zarezadeh Reza BeygiCo3W2Si intermetallic compound was synthesized by mechanical alloying (MA) of W, Co and Si elemental powder mixtures. The phase composition of the milled products was evaluated by X-ray diffraction (XRD) analysis. Morphological evolutions were characterized by transmiss أکثرCo3W2Si intermetallic compound was synthesized by mechanical alloying (MA) of W, Co and Si elemental powder mixtures. The phase composition of the milled products was evaluated by X-ray diffraction (XRD) analysis. Morphological evolutions were characterized by transmission electron microscopy (TEM). The results showed that high energy ball milling performed in the present work led to the formation of Co3W2Si intermetallic phase after 50h MA. A thermodynamic analysis of the process was then carried out using Miedema model. The thermodynamic results showed that there exists a positive thermodynamic driving force in W–Si and Co-Si binary systems and W-Co-Si ternary system to form a solid solution at all compositions but Gibbs free energy change in Co-W binary system is positive for solid solution formation. So that, there is no thermodynamic force to form a solid solution in Co-W system. In Co-W-Si ternary system, the addition of elemental W to Co3Si compound decreases Gibbs free energy change and more stable structure forms. تفاصيل المقالة -
حرية الوصول المقاله
13 - Adsorption of phosgene on Al12N12 nanocluster: Quantum chemical study
A Amiri Reza Ghiasi Karim Zare Reza FazaeliThis study investigated the adsorption of phosgene gas on Al12N12 nano-cluster with using CAM-B3LYP functional. Six possible isomers of the interaction between Al12N12 nano-cluster and phosgene were considered. The interactions between nano-cluster and phosgene were exa أکثرThis study investigated the adsorption of phosgene gas on Al12N12 nano-cluster with using CAM-B3LYP functional. Six possible isomers of the interaction between Al12N12 nano-cluster and phosgene were considered. The interactions between nano-cluster and phosgene were examined through energy decomposition analysis (EDA). Charge transfer between fragments were illustrated with electrophilicity-based charge transfer (ECT). Thermodynamics parameters of the interaction between of nano-cluster and phosgene gas were calculated. The temperature and pressure effects on the thermodynamic parameters were illustrated.Computational investigation of the adsorption behavior of phosgene on Al12N12 cage revealed e-isomer was most stable isomer in between the studied isomers. The calculated Ecoh values showed that e-isomer was most stable isomers. The larger HOMO-LUMO gap value in the e-isomer of Al12N12… COCl2 rather than Al12N12 cage showed that COCl2 adsorption meaningfully increase this value. Therefore, we believe that the Al12N12 may be a suitable nanoscale carrier for COCl2 gas. The positive value of ECT revealed charge flow from Al12N12 to COCl2 gas. Thermodynamics analysis showed that easy adsorption under lower temperature and higher pressure. تفاصيل المقالة -
حرية الوصول المقاله
14 - Quantum chemical study of the adsorption of phosgene on Al12N12 nano-cluster
Asma Amiri Reza Ghiasi Karim Zare Reza FazaeliThis study investigated the adsorption of phosgene gas on Al12N12 nanoclusterusing CAM-B3LYP functional. Six possible isomers of the interaction betweenAl12N12 nanocluster and phosgene were considered. The interactions betweennanocluster and phosgene were examined throu أکثرThis study investigated the adsorption of phosgene gas on Al12N12 nanoclusterusing CAM-B3LYP functional. Six possible isomers of the interaction betweenAl12N12 nanocluster and phosgene were considered. The interactions betweennanocluster and phosgene were examined through energy decomposition analysis(EDA). Charge transfer between fragments was illustrated with, electrophilicitybasedcharge transfer (ECT). Thermodynamics parameters of the interactionbetween nanocluster and phosgene gas were calculated. The temperature andpressure effects on the thermodynamic parameters were illustrated. تفاصيل المقالة -
حرية الوصول المقاله
15 - طبقهبندی شاخص آنتروپی اقتصادی در یک مدل کلان اقتصادی
بهروز صادقی عمروآبادی محسن رنانیهدف این مقاله طبقه بندی شاخص آنتروپی اقتصادی در یک مدل کلان اقتصادی است. بدین منظور، از روش توصیفی - تحلیلی و نظریه سیستم ها در یک مدل کلان اقتصادی استفاده شد. یافتهها نشان میدهد شاخص آنتروپی اقتصادی در یک مدل کلان اقتصادی به چهار بخش آنتروپی شوک، آنتروپی تنفس، آنتروپ أکثرهدف این مقاله طبقه بندی شاخص آنتروپی اقتصادی در یک مدل کلان اقتصادی است. بدین منظور، از روش توصیفی - تحلیلی و نظریه سیستم ها در یک مدل کلان اقتصادی استفاده شد. یافتهها نشان میدهد شاخص آنتروپی اقتصادی در یک مدل کلان اقتصادی به چهار بخش آنتروپی شوک، آنتروپی تنفس، آنتروپی خواب و آنتروپی زباله تقسیمبندی می شود. افزایش شاخص آنتروپی اقتصادی با توجه به بروز مشکلات کمیابی منابع زیستمحیطی، امکان وقوع فاجعهای اقتصادی محتملتر میشود. این رخداد، نه تنها رشد اقتصادی بلکه محیطزیست به مثابه مکان زندگی را نیز با مشکلات جدی روبرو خواهد کرد. با توجه به نتایج، کاهش بیثباتیها و فشارهای بیرونی جهت کاهش آنتروپی شوک، تدوین قوانین مناسب برای بنگاههای تولیدی جهت کاهش آنتروپی تنفس، سیاستهای مبتنی بر کاهش زبالههای فیزیکی و زبالههای اجتماعی جهت کاهش آنتروپی هرزروی پیشنهاد میشود. تفاصيل المقالة -
حرية الوصول المقاله
16 - Kinetics and thermodynamics of the esterification reaction according to the Langmuir-Hinshelwood mechanism
Rohollah EzzatiIn this work, kinetics and thermodynamics of esterification reaction were studied. This research investigated the esterification reaction between methanol and acidified oil catalyzed by sulfonated cation exchange resin and proposed a new rate equation for consideration أکثرIn this work, kinetics and thermodynamics of esterification reaction were studied. This research investigated the esterification reaction between methanol and acidified oil catalyzed by sulfonated cation exchange resin and proposed a new rate equation for consideration of kinetics of this reaction according to the Langmuir-Hinshelwood mechanism. Thermodynamics and kinetics parameters were calculated according to this equation. The results of this study showed that this new equation was a reasonable equation for kinetics study of the esterification reaction. Also, kinetics parameters were calculated for this reaction. Activation energy and Arrhenius pre-exponential factor were equal to and respectively. تفاصيل المقالة -
حرية الوصول المقاله
17 - Adsorption study of patent blue VF using ginger waste material
Rais Ahmad Rajeev KumarGinger waste material (GWM) has been utilized as adsorbent for removal of hazardousPatent Blue VF (PBVF) dye from aqueous solution. Batch adsorption experiments wereperformed as a function of pH, contact time, dye concentration, adsorbent dose and temperature.The optimu أکثرGinger waste material (GWM) has been utilized as adsorbent for removal of hazardousPatent Blue VF (PBVF) dye from aqueous solution. Batch adsorption experiments wereperformed as a function of pH, contact time, dye concentration, adsorbent dose and temperature.The optimum pH required for the maximum adsorption was found to be 2. The experimentalequilibrium adsorption data were tested using Langmuir and Freundlich isotherm equations andmaximum monolayer adsorption capacity was found to be 9.56 mg/g. Adsorption kinetics datawere modeled using the pseudo first order and pseudo second order kinetic equations andintraparticle diffusion model. Results indicate that pseudo second order model best describeadsorption kinetics data. تفاصيل المقالة -
حرية الوصول المقاله
18 - Kinetic and thermodynamic studies of the removal of murexide from aqueous solutions on to activated carbon
Ardeshir Shokrollahi Mehrourang Ghaedi Mojdeh Ranjbar Ameneh AlizadehThe objective of this study was to assess the adsorption potential of activated carbon (AC) asan adsorbent for the removal of Murexide (Mu) from aqueous solutions. The influence of variablesparameters including pH, amount of adsorbent, sieve size of adsorbent, temperatu أکثرThe objective of this study was to assess the adsorption potential of activated carbon (AC) asan adsorbent for the removal of Murexide (Mu) from aqueous solutions. The influence of variablesparameters including pH, amount of adsorbent, sieve size of adsorbent, temperature and contact timeon Mu removal was studied. Following optimization of variables, the relation between concentrations ofdye remained in aqueous and adsorbent has been evaluated using various adsorption isotherm modelslike, Langmuir, Freundlich, Tempkin, Harkins-Jura and Dubinin–Radushkevich. Thermodynamicparameters such as enthalpy (ΔH◦), and, entropy (ΔS◦), activation energy (Ea), stickingprobability (S*), and Gibb’s free energy changes (ΔG◦) were also calculated. It was found fromevaluated different thermodynamic parameters, viz., ΔH◦, ΔS◦ and ΔG◦ that the adsorption of Muby AC was feasible, spontaneous and endothermic process. The kinetic studies suggest that the allprocess following pseudo second order kinetics and involvement of intera- particle diffusion mechanism.The results indicated that the intraparticle diffusion also is the rate limiting factor. تفاصيل المقالة -
حرية الوصول المقاله
19 - Adsorption Features Remove a Toxic Dye from an Aqueous Solution by a Cost-effective Palm Leaf Activated Carbon (PLAC)
Ali M. Mohammed Aseel M. Aljeboree Ahmed B. Mahdi Yasir Salam Karim Mohammed Abed Jawad Ayad F. AlkaimThis research addressed the elimination of the dye Congo red (CR) from an aqueous solution utilizing dried palm leaf activated carbon (PLAC). Therefore, we performed batch experiments for isotherms and sorption kinetics. According to the experimental data, the adsorptio أکثرThis research addressed the elimination of the dye Congo red (CR) from an aqueous solution utilizing dried palm leaf activated carbon (PLAC). Therefore, we performed batch experiments for isotherms and sorption kinetics. According to the experimental data, the adsorption method largely depends on the equilibrium time, initial concentration of dye, pH solution, and adsorbent amount. We observed sorption equilibrium for the dye Congo red via PLAC in 60 min and an adsorption capacity of 52.1 mg g-1. A pseudo-first-order kinetic model was followed by sorption kinetics, whereas the Langmuir isotherm has been proposed to be help reache the equilibrium factor. The above data demonstrated that PLAC is an effective, low-cost, and environmentally friendly biomaterial for removing the dye from the aqueous solution. تفاصيل المقالة
سند
Sanad is a platform for managing Azad University publications
الروابط
المراكز ذات الصلة
دعامة
الصفحات الرسمية
حقوق هذا الموقع الإلكتروني مملوكة لنظام SANAD Press Management. © 1442-1446