Nanocomposites and nanomaterials

Study of adsorption kinetics of methylene blue onto the surface of composites ТіО2/activated carbon
Kukh A.A., Ivanenko I.M., Byts O.V.
National technical university of Ukraine “Igor Sikorsky Kyiv polytechnic institute”, Peremohy ave., 36, room 145, 03056 Kyiv, Ukraine              E-mail: angela.kukh@gmail.com

Adsorption of the impurities onto the surface of a composite catalyst may be a crucial stage of the heterogeneous photocatalytic process. Processing of isotherms using kinetic models of pseudo-first and pseudo-second order allows to identify its’ limiting stages [1]. In case of the use of functional materials that contain immobilized TiO2 particles, the chemical reaction between the adsorbate and the functional groups of the adsorbent may contribute to the kinetics of adsorption.
The composites series TiO2/activated carbon (ТіО2/AC) based on the original activated carbon Norit SAE SUPER were synthesized using the low-temperature hydrolysis method [2]. 
The experimental data were processed using kinetic models (Table 1). To establish a model that best describes the adsorption of methylene blue (MB) dye onto composites, the regression coefficients for each model were compared.
Table 1. Kinetic parameters of adsorption of dye onto the composites
Sample	Pseudo-first order	Pseudo-second order	
	K1, min-1	qe(calc), mg/g	R2	K2, g/(mg·min)	qe(calc), mg/g	R2	
ТіО2/AC(1)	0,1087	45,8	0,9841	0,0011	71,94	0,9870	
ТіО2/AC(2)	0,1019	45,01	0,9997	0,0025	56,5	0,9993	
ТіО2/AC(3)	0,1016	11,07	0,9471	0,0357	23,98	0,9997	
ТіО2/AC(4)	0,2350	50,71	0,9798	0,0050	45,04	0,9908	
ТіО2/AC(5)	0,2971	25,83	0,8713	0,0181	51,28	0,9934	
As evident from Table 1 adsorption of MB is best described by the pseudo-second order model. We can assume that during the adsorption of dye onto the composites, the chemical reaction stage makes a greater contribution to the overall heterogeneous adsorption and photocatalytic processes.

1. Popoola L.T. Characterization and adsorptive bahvoir of snail shell-rice husk (SS-RH) calcined particles (CPs) towards cationic dye // Heliyon, 2019.–Vol. 5.–P.1–38.
2. Kukh A.A., Ivanenko I.M., Astrelin I.M. TiO2 and its composites as effective photocatalyst for glucosedegradation processes // Appl. Nanoscience, 2018.–P.1-6.