Interfacial integration of zirconium components with amino-modified lignin for selective and efficient phosphate capture

Abstract

Water pollution is becoming increasingly serious, and one of the main culprits is the excessive phosphate in aquatic systems. Herein, a flexibly prepared, environment-friendly sustainable and highly efficient bio-sorbent (AL-DETA@Zr) for phosphate capture was developed by diethylenetriamine-modified lignin integrated with zirconium hydroxide. The related properties and functional group changes of AL-DETA@Zr were investigated by multiple characterizations such as XRD, SEM, TGA, FTIR and XPS. According to a batch adsorption experiments, AL-DETA@Zr showed excellent thermal stability, fast adsorption rate for phosphate, and maximum sorption capacity of 167.7 mg/g. It was shown from the temperature experiments that the sorption process of phosphate over AL-DETA@Zr is endothermic and spontaneous. More importantly, it exhibited outstanding selective adsorption toward phosphate and anti-interference capability for co-existing anions. After three consecutive cycles, the sorption performance of AL-DETA@Zr did not decrease significantly, demonstrative of its excellent reusability under testing conditions. The mechanism of phosphate capture onto AL-DETA@Zr could be mainly ascribed to electrostatic attraction and ligand exchange. Accordingly, as-prepared AL-DETA@Zr would be a promising choice to remedy the excess phosphate in wastewater, due to its environment-friendly, high efficiency, excellent phosphate selectivity and mechanical stability.