HAO Yanling, ZHANG Yu, QU Aoyun

 

(School of Chemical and Biological Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China)

 

Abstract: The composites FO/P, MO/P and FMO/P were prepared by combining Fe-Mn oxide and palygorskite clay. The batch experiments were carried out to investigate adsorption characteristics of phosphate on composites namely adsorption kinetics, isotherm and mechanism, the effects of mass ratio of metal and palygorskite, calcination temperature, solution pH, ionic strength and vibration time. Results indicate that adsorption performance of FMO/P is better than FO/P and MO/P and its phosphate removal ratio attains 95% towards 20 mg/L phosphate solution when mass ratio of metal and palygorskite is 0.1. Adsorption is highly pH dependent while ionic strength has no significant effect and phosphate removal is achieved by the formation of inner-sphere surface complexes. Adsorption equilibrium can be reached in about 60 min and adsorption processes follow pseudo-second-order equation most effectively with the characteristic of chemical adsorption. Freundlich equation can be more suitable to describe adsorption isotherm of FMO/P, revealing higher heterogeneous adsorption and saturation adsorption capacity estimated from Langmuir equation reaches 49 mg/g.

 

Key Words: palygorskite; Fe-Mn oxide; composite; adsorption; phosphate

EARTH AND ENVIRONMENT Vol.45, No.6, Tot No.320, 2017, Page 649-653