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Adsorption/photodegradation of Congo Red on TNT surfaces: A kinetic study
Author : Saismrutiranjan Mohanty a, Sanjib Moulick b and Sanjoy Kumar Maji *a
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ABSTRACT
Hydrothermally synthesized titanate nanotubes (TNTs) were characterized and applied to remove Congo Red (CR) from synthetic as well as from the spiked tap and pond water under the optimized conditions at room temperature. Experimental results suggested that applying hydrothermally synthesized TNT at a dose of 4 g/L can remove to the tune of ~98% CR from the contaminated water medium with an initial concentration of 6 mg/L within 5.75 h. Removal followed both adsorption (0.75h, removed ~86%) and photodegradation (5.0 h, ~98% final). The adsorptive capacity of TNT was found to be 12.04 mg/g from Langmuir isotherm with physical adsorption from D-R isotherm, favorable (RL) and non spontaneous (Gº). Adsorption process followed pseudo-second order reaction model better than other three models. Like metals or metalloids, adsorption of CR did not follow either film diffusion or pore diffusion model. Study was also conducted to examine the effects of presence of coexisting ions in the removal of CR at different pH of media. Adsorption/degradation mechanism was proposed.
KEYWORD
Adsorption/photodegradation, dye, TNT, isotherm, kinetics