I have fitted the fluoride adsorption kinetics data to Lagergren’s pseudo-first order and Ho's pseudo-second order kinetic models. What do these kinetic models explain about the adsorption kinetics?
Please find required information from the article attached below:
Hello Dayananda,
Chemical kinetics is the study of rates of chemical processes and factors that influence them in the attainment of equilibrium in a reasonable amount of time.
The most popular kinetic models are the Lagergren pseudo-first order and pseudo-second order kinetics. For many adsorption processes, the pseudo-first order kinetics was found to be suitable for only the initial 20 to 30 minutes of interaction time and not for the whole range of contact times. K1 and qe can be evaluated from the graph of ln (qe-qt) versus t, if a straight line, and hence the adsorption follows a pseudo first order kinetics model.
If the adsorption system follows a pseudo-second order kinetics, then the rate limiting step may be chemical adsorption involving valecy forces through sharing or exchange of electrons between the adsorbent and sorbate, then a plot of t/qt versus t would be linear and k2 and qe can be determined from the intercept and gradient of the graph. One of the advantages of the pseudo-second order equation for estimating qe values, is its small sensitivity to the influence of random experimental errors. Check out my papers:
1. Zaynab Aly, Adrien Graulet, Nicholas Scales, Tracey Hanley, “Removal of aluminium from aqueous solutions using PAN-based adsorbents: characterisation, kinetics, equilibrium and thermodynamic studies, Journal of Environmental Science and Pollution Research (2014) 21: 3972-3986. DOI 10.1007/s11356-013-2305-6.
2. Z. Aly and V. Luca, “Uranium extraction from aqueous solution using dried and pyrolyzed tea and coffee wastes”, J. Radioanaly. Nucl. Chem., Volume 295, issue 2, (2013) pages 889-900. DOI: 10.1007/s10967-012-1851-6.
Dear Dr. Selvaraju Sivamani
Hello and thank you so much for your valuable explanation. Do you can please send me your paper which you listed at the end of text?
Dear Dayananda,
They are about adsorption orders.
Try attachments.
Yuh-Shan Ho
E-mail: [email protected]
http://dns2.asia.edu.tw/~ysho/
The suggestion/paper by Y S Ho Sir has helped me to understand some concept about pseudo-first and second order kinetic model for adsorption process. Thank you Sir.
Hi dear Dayanandan
You can visit the attached page to understand more and more about kinetics data.
https://chem.libretexts.org/Core/Physical_and_Theoretical_Chemistry/Kinetics/Reaction_Rates/Second-Order_Reactions/Pseudo-1st-order_reactions
Yours faithfully
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