“…More recently, Molina et al (2014) demonstrated that U-PEO with molar mass of 500 g mol − 1 provided selective adsorption of anionic dyes, rather than cationic dyes. In other work, hybrid matrices composed of 3-glycidoxypropyl-trimethoxysilane (GPMS) linked to end-group functionalized polyetheramines (U-PEO and U-PPO) showed good adsorption capacity (415 mg g − 1 ) for the rose bengal anionic dye (Moura et al, 2015). Montmorillonite (Mt) is an efficient adsorbent of cationic dyes such as methylene blue (MB), crystal violet, methyl violet, basic blue 16, and others (Aladağ et al, 2014;Almeida et al, 2009;Fil et al, 2012;Gunay et al, 2013;Zhu et al, 2014).…”