Highly efficient and reusable magnetic anion-exchange microbeads for reactive dye removal

A novel magnetic anion exchange microbead (NAEM) with excellent reuse and anti-fouling performance was developed, and used for removal of an reactive dye sunset yellow (FCF). The NAEM initial adsorption rate was 16.7-, 25.8-, 31.6-, and 31.6-fold that of commercial IRA-958, D201, A520, and IRA-900 resins, respectively. The adsorption of FCF on different anion-exchange resins appeared to be multilayered, implying physical adsorption also contributes to FCF removal. The polyacrylic resin matrix exhibited higher affinity than the polystyrene matrix towards FCF. The equilibrium adsorption capacity for FCF at 298 K was in the following order: NAEM (1.95 mmol/g) > IRA-958 (1.01 mmol/g) > D201 (0.85 mmol/g) > A520 (0.81 mmol/g) > MAER (0.78 mmol/ g) > IRA-900 (0.59 mmol/g). NAEM reinforced the anti-interference capacity of FCF adsorption when the concentrations of NaCl or Na2SO4 were lower than 20 mmol/L. After 10 cycles of regeneration, the FCF adsorption capacity of NAEM was 1.76-, 2.79-, 2.81-, 3.05-, and 5.26-fold higher than MAER, IRA-958, D201, A520, and IRA-900, respectively. The high adsorption capacity and excellent reusability may facilitate the practical applications of NAEM in wastewater treatment against reactive dyes.