Exclusion of crystal violet and methylene blue from wastewater using titanate nanotube: Kinetics of the adsorption and photodegradation

Department of Chemistry, School of Applied Sciences, KIIT Deemed to be University, Bhubaneswar-751 024, Odisha, India School of Civil Engineering, KIIT Deemed to be University, Bhubaneswar-751 024, Odisha, India E-mail: maji.sanjoy@gmail.com Manuscript received online 09 December 2020, accepted 28 December 2020 Photo-adsorption of crystal violet (CV) and methylene blue (MB) from synthetic wastewater using hydrothermally synthesized titanate nanotubes (TNTs), a cheap adsorbent/photocatalyst was reported. Experimental results suggested 3 g/L dose of TNTs could efficiently adsorb/degrade CV (initial concentration: 20 mg/L) and MB (10 mg/L) to the tune of ~95% and ~98% respectively at agitation speed of 520±20 rpm and pH of 6.8±0.2. The effects of contact time, dose of adsorbent and dye concentration were investigated. Decolorisation of dyes from aqueous media followed adsorption and photodegradation in UV-light. The adsorption process of both dyes followed the pseudo-second order reaction model, whereas, for photodegradation it was arbitrary. The plausible photodegradation mechanism was proposed. The adsorption process follows neither the pore diffusion nor the film diffusion model. Turnover study results suggested the gradual suppression of loading solute dye on TNT surfaces