Efficient removal of acid dyes using permanent magnetic resin and its preliminary investigation for advanced treatment of dyeing effluents

In order to deal with the contamination of dyes in wastewater, a new kind of magnetic strongly basic anion-exchange resin (noted as CDD-1) was prepared and characterized in this study. Batch experiments were performed to investigate its adsorption behaviors of two acid dyes sunset yellow (FCF) and acid green (AG9) under different experimental conditions. The reusability and adsorption performance of CDD-1 resin for biologically treated dyeing effluents treatment were also evaluated. The maximum adsorption capacity of FCF and AG9 onto CDD-1 resin at 308 K were 1.85 and 1.44 mmol/g, respectively. When the initial concentrations of two dyes were 0.05, 0.25 and 0.50 mmol/L, the initial adsorption rates of FCF were 1.76, 4.09 and 7.37 times higher than that of AG9, respectively. The FCF appeared a homogeneous monolayer chemisorption, while the AG9 adsorption was more like a multilayer adsorption, indicating other interactions except ion exchange may occur during the AG9 adsorption. The CDD-1 resin could be reused with most of its virgin adsorption capacity (93.6% for FCF and 78.9% for AG9) after 10 successive adsorption-desorption cycles. For real dyeing effluents treatment by the CDD-1 resin, the removal efficiencies of color degree were more than 90%, while that of CODcr were about 35-60%, which rendered it great potential for advanced treatment of dyeing effluents. (C) 2019 Elsevier Ltd. All rights reserved.