Chemisorption of basic fuchsine in packed beds of dialdehyde cellulose fibres

Abstract

The discharge of textile dyes in water systems, due to poor binding to fabrics, is a major health and environmental concern. The majority of synthetic dyes used in textile are hazardous and carcinogenic. Despite efforts in addressing challenges associated with covalent binding of dyes to fibers and effluent filtration, there has been no promising green solution based on green materials and chemistry. Here, we demonstrate that dialdehyde cellulose (DAC) engineered through the chemical functionalization of cellulose fibres provides great functionality for Schiff base dye conjugation. Breakthrough curves (BTCs) of basic fuchsine in packed beds of DAC fibers were fitted to a Langmuir model and pseudo-first order kinetics. DAC fibers with an aldehyde density of 10.8 mmol g-1 had an adsorption capacity, adsorption and desorption rates of 204 mg g-1, 0.05 min-1 and 9.0 × 10-5 min-1, respectively. For cellulose fibers, used as a control, these values are 61 mg g-1, 0.15 min-1 and 2.6 × 10-3 min-1, respectively. It is shown that all dye is chemisorbed on DAC fibres, after initial physisorption and ion-exchange. Addition of 1 M NaCl to the dye solution resulted in coagulation of the dye and the removal capacity through filtration increased to 489 mg g-1, a process ideal for dye recovery or water purification.