Adsorption of methylene blue on lithium titanate and its composite with carbon dots: Optimization of parameters and adsorbent recovery

Bazzi, Mohadeseh; Yavari, Zahra; Shahbakhsh, Mehdi

doi:10.22104/jpst.2026.8046.1288

Adsorption of methylene blue on lithium titanate and its composite with carbon dots: Optimization of parameters and adsorbent recovery

Document Type : Research Article

Authors

Mohadeseh Bazzi

Zahra Yavari

Mehdi Shahbakhsh

Department of Chemistry, University of Sistan and Baluchestan, Zahedan, Iran

10.22104/jpst.2026.8046.1288

Abstract

Porous lithium-titanium oxide (pLT) was produced by the combustion synthesis method. Based on the XRD pattern, the as-synthesized powder phase was Li₂TiO₃. The carbon dots were incorporated onto the lithium titanate sponge (pLT-CD) using the microwave method and natural precursors. Two synthesized structures were used to remove methylene blue from wastewater. A morphological comparison of pLT and pLT-CD was performed using field emission scanning electron microscopy. Elemental mapping of the pLT-CD composite was used to investigate the dispersion of CD on pLT and its stability in aqueous media. The experiments of methylene blue removal by adsorbents were designed using the Taguchi method. The effect of pH, time, temperature, and methylene blue concentration on the treatment process by pLT and pLT-CD was studied. The maximum removal percentage was observed at pH 8, room temperature, 10 min, and 40 ppm dye concentration on the pLT-CD composite adsorbent. The adsorption equilibrium was better described by the Freundlich isotherm, indicating multilayer adsorption on heterogeneous surfaces. Kinetic results followed a pseudo-second-order model, with pLT-CD showing a higher adsorption rate due to enhanced surface interactions and increased active sites. Adsorbent recovery was performed by UV-Vis irradiation on the saturated adsorbent to decompose the adsorbed dye. An efficiency drop of about 20 and 13.60 % was observed for pLT and pLT-CD, respectively, after four consecutive cycles

Graphical Abstract

Adsorption of methylene blue on lithium titanate and its composite with carbon dots: Optimization of parameters and adsorbent recovery

Highlights

Fabrication and characterization of porous Li₂TiO₃(pLT)
Incorporation of carbon dots on Li₂TiO₃(pLT-CD)
Analysis of the adsorption of methylene blue on pLT and pLT-CD
Optimization of adsorption parameters

Keywords

Taguchi method

Adsorbent recovery

Carbon dots

Porous lithium-titanium oxide

Dye removal

Subjects

Adsorption

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