Amine-functionalized magnetic microspheres from lignosulfonate for industrial wastewater purification.

Amine-functionalized magnetic microspheres (LS-Fe-NMA) were successfully prepared from lignosulfonate by magnetization and amine modification to remove Cr(VI) from industrial wastewater. In addition to SEM, FTIR, XPS, magnetic hysteresis curves and other characterizations, the adsorption tests were performed in real Cr(VI)-containing industrial wastewater. The experimental influencing factors, such as adsorbent types, LS content in the composites, adsorption time, dosages of adsorbent and adsorption temperature were systematically explored. The results of adsorption models fitting proved that the adsorption conformed to the Langmuir model and the pseudo-second-order kinetic model. At 45 °C, the calculated equilibrium adsorption amount by LS-Fe-NMA in industrial wastewater was 642.11 mg/g. In addition, the adsorption process followed the principle of spontaneous endothermic reaction. It was found that electrostatic interaction, redox and complexation existed during the adsorption process. The excellent adsorption performance and reusability of LS-Fe-NMA for Cr(VI) demonstrates its practical application value in real Cr(VI)-containing industrial wastewater.