Calixarene-Based\nFunctional Fabric for Simultaneously\nAdsorptive Removal of Anionic and Cationic Dyes

This study investigated the adsorptive properties of\nfunctionalized\nfabric containing dimethylaminomethyl calix[4]­arene (DMAM-Calix) to\nremove anionic methyl orange (MO) and cationic Rhodamine B (RhB) dyes\nin aqueous media. Adsorption studies were performed using a filtration\nsystem packed with DMAM-Calix-functionalized fabric (<b>DCF</b>). The results revealed that the cationic and anionic structures\nwork compatibly in a binary mixture medium. Hydrogen bonding, π–π,\ncation–π, <i>n</i>–π and electrostatic\ninteractions between dye molecules and DMAM-Calix units of <b>DCF</b> were the main factors affecting the adsorption process. Experiments\non real wastewater samples of unknown composition confirmed that the\napproach could successfully remove MO and RhB dyes from real water\nsamples with high efficiency, especially for RhB. Isotherm and kinetic\ndata for MO were mainly represented by the Langmuir model and pseudo-second-order\nkinetic model, respectively. The adsorption capacities of <b>DCF</b> were found to be about 4.7 mg g<sup>–1</sup> for MO and 1.0\nmg g<sup>–1</sup> for RhB at pH 6.0, which were evaluated as\nsatisfactory considering the first use of a calixarene-derived coated\nfabric as an adsorbent, the anionic–cationic dye selectivity\nof <b>DCF</b>, and the low cost and ease of application of the\nmethod.