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Article
INCREASING THE ADSORPTION SURFACE AREA OF ACTIVATED CARBON

Authors: Shahlaa E. Ebrahim --- Abbas H. Sulaymon
Journal: Journal of Engineering مجلة الهندسة ISSN: 17264073 25203339 Year: 2008 Volume: 14 Issue: 3 Pages: 2700-2717
Publisher: Baghdad University جامعة بغداد

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Abstract

Experiments were carried out to study the effect of various activated carbon-glass beads weight ratios, influent phenol concentrations, flow rate and bed depth on the performance of fixed bed adsorption column. The equilibrium data and interparticle diffusion coefficients obtained from separate experiments in a batch adsorber were fitted with theoretical model. The effect of adding different weight ratios of an inert solid material to the adsorbent bed in the adsorption process of phenol onto activated carbon was carried out. Adding 5 wt % glass beads to the activated carbon bed reduces the amount of activated carbon by 5% and increases the operating time by 80%.. Increasing the glass beads from 10 wt % and above makes the adsorption process inefficient compared with 0 wt % glass beads. A mathematical model was achieved to describe the mass transfer kinetics in a fixed bed column. The results show that the mathematical model includes external mass transfer and pore diffusion using nonlinear isotherms, provides a good description of the adsorption process for phenol in fixed bed adsorber.


Article
Utilization of Thomas model to predict the breakthrough curves for adsorption and ion exchange

Authors: Shahlaa E. Ebrahim --- Yasmen A. Mustafa
Journal: Journal of Engineering مجلة الهندسة ISSN: 17264073 25203339 Year: 2010 Volume: 16 Issue: 4 Pages: 6206 -6223
Publisher: Baghdad University جامعة بغداد

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Abstract

Fixed bed sorption processes such as adsorption and ion exchange do not operate at steady state. The design equations are differential that usually require numerical methods to solve. Thomas gives a general analytical solution for these equations. It is based on second-order reaction kinetics and the assumption of Langmuir isotherm. Computer program for the solution of Thomas model was designed using MATLAB 7.0. Four sets of experimental data are tested to show the capability of Thomas model to predict the breakthrough curves for adsorption and ion exchange processes. These data represent the sorption of o-cresol from water by activated carbon, acetic acid from air by activated carbon, phenol from water by natural zeolite, and trichloroethylene from air by zeolite-5A.The results show that there are a good agreement between the experimental data and the model.

أن عمليات الامتزاز والتبادل الايوني للطور الثابت تكون متغيرة ، فالمعادلات الخاصة بالتصاميم هي معادلات تفاضلية تحتاج الى حلول بالطرق العددية.توماس استطاع أن يعطي حل عام تحليلي لهذه المعادلات مستندا على ديناميكية التفاعل من الدرجة الثانية ومعادلة لانكمير عند التوازن. تم اعداد برنامج رياضي لموديل توماس بأستخدام MATLAB 7.0 . أستخدمت اربعة نماذج من التجارب لغرض أظهار مقدرة موديل توماس للتنبأ بمنحنيات الامتزاز والتبادل الايوني. البيانات مثلت امتزاز الاورثوكريسول من الماء بواسطة الفحم المنشط ، وحامض الخليك من الهواء بواسطة الفحم المنشط، والفينول من الماء بواسطة الزيولايت، وثلاثي كلوروالاثلين من الهواء بواسطة الزيولايت. النتائج بينت ان هناك تطابق جيد بين البيانات العملية والموديل.


Article
Removal of Lead, Cadmium, and Mercury Ions Using Biosorption

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Abstract

The biosorption of Pb (II), Cd (II), and Hg (II) from simulated aqueous solutions using baker’s yeast biomass was investigated. Batch type experiments were carried out to find the equilibrium isotherm data for each component (single, binary, and ternary), and the adsorption rate constants. Kinetics pseudo-first and second order rate models applied to the adsorption data to estimate the rate constant for each solute, the results showed that the Cd (II), Pb (II), and Hg (II) uptake process followed the pseudo-second order rate model with (R2) 0.963, 0.979, and 0.960 respectively. The equilibrium isotherm data were fitted with five theoretical models. Langmuir model provides the best fitting for the experimental results with (R2) 0.992, 0.9987, and 0.9995 for Cd (II), Pb (II), and Hg (II) respectively. The effect of various influent adsorbates concentrations, and flow rates on the performance of fixed bed adsorber was found for the three heavy metals. A mathematical model was formulated to describe the breakthrough curves in the fixed bed adsorber for each component. The results show that the mathematical model provides a good description of the adsorption process for Cd (II), Pb (II), and Hg (II) onto fixed bed of baker’s yeast biomass.

Keywords

Biosorption --- yeast --- Cd --- II --- Pb --- II --- Hg --- II --- fixed bed --- mathematical model --- mass transfer coefficient.


Article
Competitive Removal of Cu2+, Cd2+and Ni2+by Iron Oxide Nanoparticle (Fe3O4)
الازالة التنافسية لايونات النحاس والكادميوم والنيكل بواسطة مادة النانو المازة(اوكسيد الحديد)

Authors: Hasanain Saad Alhares حسنين سعد عبد الزهرة الحارس --- Shahlaa E. Ebrahim شهلاء اسماعيل ابراهيم
Journal: Journal of Engineering مجلة الهندسة ISSN: 17264073 25203339 Year: 2015 Volume: 21 Issue: 4 Pages: 98-122
Publisher: Baghdad University جامعة بغداد

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Abstract

A competitive adsorption of Cu2+, Ni2+, and Cd2+ ions from a synthetic wastewater onto nanomaterial was studied.(Fe3O4) nanoparticles obtained from US Research Nanomaterials, Inc., Houston, TX 77084, (USA), was used as nanosorbent. Experimental parameters included pH, initial metal concentrations, and temperature were studied for nanosorbent. The uptake capacity 11.5, 6.07 and 11.1 mg/g for Cu2+, Ni2+and Cd2+, respectively, onto nanosorbent . The optimum pH values was 6 and the contact time was 50 min. for Cu2+, Ni2+and Cd2+, respectively. The equilibrium isotherm for nanosorbent single system component is of a favorable type and Freundlich isotherm model gives the best fit model for representing the experimental data for this system. Binary and ternary component systems were conducted in order to find the adsorption isotherm constants for each component system using nanosorbent. A set of adsorption models were tested to choose the best fit model for the experimental data, Combination of Langmuir- Freundlich model seems to give the best fitting. In single, binary and ternary component systems, Cu2+ always adsorbed more favorable onto nanosorbent than Cd2+and Ni2+. The adsorption capacity parameters were: Cu2+> Cd2+> Ni2+. Thermodynamic study was carried out for these three pollutants onto nanosorbent. The results of adsorption show that the adsorption nature for heavy metals is an endothermic and physical nature process.

الدراسة الحالية تهدف الى تقييم عملية الامتزاز للمعادن الثقيلة(النحاس،النيكل و الكادميوم) من المياه الصناعية بواسطة مادة النانو.وتم شراء مادة النانوالمازة وهي اوكسيد الحديد (Fe3O4) من الولايات المتحدة الامريكية. كذلك تم دراسة تغيير بعض العوامل المختبرية على عملية الامتزاز مثل الدالة الحامضية، التركيز الاولي، والحرارة لمادة النانو. ان سعة الازالة هي 11.1,6.07,11.5mg/g لايونات النحاس والنيكل والكادميوم على التوالي باستخدام مادة النانو. وجد ان افضل نسب الازالة لمادة النانو تحصل عند قيمة الحامضية 6 لجميع الايونات وان وقت الازالة الامثل هو 50 دقيقة . تم القيام بسلسلة من تجارب الدفعات (batch experiment) للملوثات بصورة منفردة وثنائية وثلاثية لغرض الحصول على مخططات الامتزاز الحيوي لكل ملوث. وقد تم استخدام عدد من الموديلات الرياضية التي تصف عملية الامتزاز. وجد أن موديل (Freundlich) ، أفضل موديل رياضي يمثل النتائج العملية بالنسبه للمنفرده.اما بالنسبة الى التجارب الثنائية والثلاثية ، وجد ان موديل (Combination of Langmuir- Freundlich) افضل موديل رياضي يمثل النتائج العملية. وجد أن ايونات النحاس اعلى قدرة وملائمة على الامتزاز بواسطة مادة النانو بينما ايونات النيكل اقل قدرة من بقية الايونات . كما وجد ان طبيعية الامتزاز للمعادن الثقيلة هو ماص للحرارة من خلال التجارب الحرارية (thermodynamic study) وذو طبيعة فيزياوية.

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