A Comparative Kinetic and Thermodynamic Adsorption Study of Methylene Blue and Its Analogue Dye on Filter Paper
Bogyor A. Csavdari A.A. Lovász T. Bitay E.
January 2025Multidisciplinary Digital Publishing Institute (MDPI)
International Journal of Molecular Sciences
2025#26Issue 2
A comparative adsorption study was carried out for methylene blue (MB) and its 3,7-bis(N,N-(2-hydroxyethyl)amino)-phenothiazinium dye analog (MBI). Batch experiments employed aqueous solutions and commercial filter paper. Out of seven kinetic models tested by means of four quality statistical indicators, the pseudo-second-order, the double-exponential, and the bi-linear Weber–Morris equations were best fits. For both dyes, the process was described as a succession of two diffusion-controlled steps. The Freundlich isotherm was chosen from 11 models describing a variety of mechanism assumptions. Physisorption was considered responsible for the dye removal from liquid. Adsorption of MB is thermodynamically favored, whereas that of MBI is sterically hindered. Both processes are exothermic and exhibit reduced randomness at the S-L interface. The paper was found suitable for retaining MB but served rather filtration/purification purposes for MBI.
adsorption , adsorption isotherms , adsorption kinetics , adsorption thermodynamics , filter paper , methylene blue , methylene blue analog , model quality statistical indicators
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Department of Chemical Engineering, Babeş-Bolyai University of Cluj-Napoca, Arany Janos Street 11, Cluj-Napoca, 400028, Romania
Department of Analytical, Colloidal Chemistry and Technology of Rare Elements, Al-Farabi Kazakh National University, 71 Al-Farabi Avenue, Almaty, 050040, Kazakhstan
Department of Mechanical Engineering, Faculty of Technical and Human Sciences, Sapientia Hungarian University of Transylvania, Calea Sighișoarei 2, Târgu-Mureş, 540485, Romania
Bánki Donát Faculty of Mechanical and Safety Engineering, Óbuda University, Bécsi Street 96/b, Budapest, 1034, Hungary
Research Institute of the Transylvanian Museum Society, Napoca Street 2-4, Cluj-Napoca, 400009, Romania
Department of Chemical Engineering
Department of Analytical
Department of Mechanical Engineering
Bánki Donát Faculty of Mechanical and Safety Engineering
Research Institute of the Transylvanian Museum Society
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