Iranian Research Organization for Science and Technology Journal of Particle Science and Technology 2423-4087 11 2 2025 12 01 Adsorption of methylene blue on lithium titanate and its composite with carbon dots: Optimization of parameters and adsorbent recovery 101 116 1687 10.22104/jpst.2026.8046.1288 EN Mohadeseh Bazzi Department of Chemistry, University of Sistan and Baluchestan, Zahedan, Iran Zahra Yavari Department of Chemistry, University of Sistan and Baluchestan, Zahedan, Iran 0000-0003-1049-0448 Mehdi Shahbakhsh Department of Chemistry, University of Sistan and Baluchestan, Zahedan, Iran Journal Article 2025 12 09 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 https://jpst.irost.ir/article_1687_7fea637fd6d02b8f0adf6f7dc36aed93.pdf