Adsorption characteristics of phosphorus from aqueous solutions onto phosphate mine wastes

The present study aims to investigate the key parameters and mechanisms affecting the removal of phosphorus ions from aqueous solutions onto phosphate mine slimes (PMS) in batch mode. PMS is an abundant waste generated by phosphate mine industry. The results indicate that phosphorus removal increases with increasing initial aqueous phosphorus concentrations, adsorbent dosage and temperature, and decreased with increasing pH values. The adsorption data kinetic modeling, the energy dispersive spectroscopy (EDS) and the Fourier transform infra-red spectroscopy (FTIR) analysis before and after adsorption of phosphorus onto PMS show that the main involved mechanisms are both ion exchange with chlorides and sulphur anions and complexation with some functional groups such as hydroxyl, carboxylic and acid halides groups. Furthermore, the results of the elementary composition analysis of PMS before and after adsorption indicated that the phosphorus content in PMS has increased by about 43% which promote its potential to be used as a fertilizer. In comparison with other natural adsorbents, PMS could be considered as one of the most efficient natural materials for the removal and recovery of phosphorus with the possibility of agronomic reuse as fertilizer.