کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
221531 464260 2016 12 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Thermodynamic parameters of cadmium adsorption onto orange peel calculated from various methods: A comparison study
ترجمه فارسی عنوان
پارامترهای ترمودینامیکی جذب کادمیوم بر روی پوست پرتقال بدست آمده روش های مختلف: مطالعه مقایسه
کلمات کلیدی
ثابت تعادل. پارامترهای ترمودینامیکی؛ جذب فیزیکی؛ جاذبه الکترواستاتیک؛ کادمیوم؛ پوست پرتقال پیشنهاد ویرایش
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی مهندسی شیمی (عمومی)
چکیده انگلیسی


• The thermodynamic parameters were calculated from the Langmuir, Freundlich, Henry, and partition constants.
• The thermodynamic parameters were strongly dependent on derivation of the applied constants.
• The Langmuir and Freundlich constants (dimensionless) were appropriate for calculating the thermodynamic parameters.
• The adsorption mechanism involved physical adsorption.
• Electrostatic attraction played a primary role in the adsorption process (∼90%).

Thermodynamic adsorption investigation plays a key role in estimating adsorptive mechanisms (i.e., physical or chemical). Accuracy estimation of the thermodynamic parameters is directly dependent on the equilibrium constant between two phases (KC; dimensionless). In this study, the thermodynamic parameters were calculated from the KC constants derived from the adsorption isotherm constants (i.e., Langmuir, Freundlich, and Henry) and partition coefficient, with and without dimensionality consideration. Results showed that the optimal selection of KC is strongly dependent on: the adsorption characteristics (i.e., Henry, Freundlich, and Langmuir) where equilibrium data are actually located; and the correlation coefficient of the van’t Hoff equation. Both the Langmuir and Freundlich constants (dimensionless) are appropriate to calculate the thermodynamic parameters. The Langmuir constants from its four linear forms can be applied to calculate the thermodynamic parameters without significant difference. The Cd(II) biosorption process onto the orange peel (OP) occurred spontaneously (−ΔG°), in an exothermic nature (−ΔH°), and with increased randomness (+ΔS°). The biosorption process involved physical adsorption with minimal activation energy (Ea) and adsorption energy (E). The biosorption phenomenon reached fast equilibrium and reversibility. The negatively charged carboxylic groups (–COO−) on the OP’s surface play an important role (approximately 90%) in Cd2+ biosorption through electrostatic attractions (out-sphere complexes).

Figure optionsDownload as PowerPoint slide

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Environmental Chemical Engineering - Volume 4, Issue 3, September 2016, Pages 2671–2682
نویسندگان
, , ,