TEMPO-Oxidized Cellulose Beads for Cationic Dye Adsorption

Abstract

Toxic organic dyes present in wastewater should be removed before discharge. In this study, TEMPO-oxidized, regenerated cellulose beads were prepared using a simple falling ball technique for cationic methylene blue (MB) removal. The obtained cellulose beads were characterized using various analytical techniques. The results indicated that TEMPO-oxidized cellulose beads displayed porous structures with high content of carboxylic acid groups. Thus, the negatively charged cellulose beads can effectively adsorb cationic MB with an adsorption capacity of 495 mg/g at a starting concentration of 100 mg/L. This simple one-step adsorption process achieved near-complete MB removal at pH 7, indicating strong electrostatic interactions between cationic MB and negatively charged oxidized cellulose beads. The experimental data can be well described by the Langmuir isotherm model and the Pseudo-second-order model. The fabricated cellulose beads exhibit great potential for practical application in dye removal from wastewater.