Sol-gel TiO₂ decorated on eggshell nanocrystal as engineered adsorbents for removal of acid dye

ABSTRACT

Calcined eggshell (CES) food residue was modified by depositing sol-gel titanium dioxide (TiO₂) nanoparticles with narrow size distribution onto it through in situ precipitation and a novel hybrid nano biosorbent, namely TiO₂-CES, was obtained. The deposition was characterized and the TiO₂-CES nano network was used for efficient adsorption of single azo class anionic dye acid red nylon 57 (AN57) from aqueous solutions and the adsorption was pH dependent. Lower pH favored the sorption at the tested different pHs of 1.0–8.0. The calcination temperature had a cogent influence on the adsorption process. The sorption process reached equilibrium within 40 min, and the mathematical models were positively verified and could be described by a pseudo-second-order pattern, while equilibrium was described with Langmuir-type equation. In addition, the reusability study has proven that 0.5 M HNO₃ was efficient enough to desorb AN57 from the hybrid nano sorbent. All results validated that TiO₂-CES is Eco-Friendly adsorbent material practical treatment of dyes contaminated water.

GRAPHICAL ABSTRACT

KEYWORDS:

• Adsorption and acid red nylon 57
• calcined eggshell
• nanocrystal
• sol-gel