Fabrication of Ananas comosus leaf extract modified titanium dioxide nano bio adsorbent for the sequestration of basic dye from aqueous phase: equilibrium and kinetic studies

Abstract

A novel, titanium dioxide nano bio-adsorbent (TiO _2 L) based on Ananas comosus leaf extract was developed by sol-gel route and was subsequently used to decolorize toxic non-biodegradable basic dye Victoria blue (VB) from the aqueous solution. Several techniques were used to characterize the synthesized bio-adsorbent like XRD, FTIR, SEM-EDX and TEM to observe physio-chemical changes and adsorption interactions. The impact of process parameters on the adsorption behavior of TiO _2 L towards VB were comprehensively studied and the optimized conditions were initial dye concentration (50 mg L ^−1 ), dose (1.8 g L ^−1 ), contact time (40 min), and pH (6) of the solution. Different isotherm and kinetic models were used to analyze the equilibrium data among which Langmuir model appropriately fitted the equilibrium data based on high R ^2 (0.994) and pseudo second order described the reaction kinetics of VB adsorption onto the adsorbent. The maximum adsorption capacity was found to be 83 mg g ^−1 . Dye loaded adsorbent was regenerated and used for 3 cycles without subsequent loss in its efficiency. Thus, economic feasibility, environmentally friendly, better sorption capacity and regeneration potential, validates TiO _2 L as a potential adsorbent for VB from wastewater.

Keywords

• adsorption
• water pollution
• isotherm
• adsorbent