title: Sequestration of phosphorus from wastewater by cement-based or alternative cementitious materials.
abstract: Cement-based and alternative cementitious materials were tested in the laboratory for their capability of removing phosphate from wastewater. The results demonstrated that both Langmuir and Freundlich adsorption isotherms were suitable for describing the adsorption characteristics of these materials. Among the four types of filter media tested, the cement-based mortar A has the highest value of maximum adsorption (30.96 mg g(-1)). The P-bonding energy (KL) and adsorption capacity (K) exhibited a positive correlation with the total content of Al2O3 and Fe2O3 in each mortar. The maximum amount of P adsorbed (Qm) and adsorption intensity (1/n) exhibited a positive correlation with the CaO content in each mortar. For three of them, the P-removal rates were in excess of 94 percent for phosphorus concentrations ranging from 20 to 1000 mg L(-1). The underlying mechanisms were examined using field emission scanning microscopy (FESEM), coupled with energy-dispersive X-ray spectroscopy (EDX) and X-ray powder diffraction (XRD). The results reveal that the removal of phosphate predominantly followed a precipitation mechanism in addition to weak physical interactions between the surface of adsorbent filter media and the metallic salts of phosphate. The use of cement-based or alternative cementitious materials in the form of ground powder shows great promise for developing a cost-effective and environmentally sustainable technology for P-sequestration and for wastewater treatment.
authors.affiliation: Corrosion and Sustainable Infrastructure Laboratory, Western Transportation Institute and Civil Engineering Department, PO Box 174250, College of Engineering, Montana State University, Bozeman, MT 59717-4250, USA; Laboratory of Road Ecology and Pollution Emergency Response, Research Center for Environmental Protection and Transportation Safety, China Academy of Transportation Sciences, Beijing 100029, China.
authors.forename: Xinjun
authors.initials: X
authors.lastname: Wang
authors.affiliation: Laboratory of Road Ecology and Pollution Emergency Response, Research Center for Environmental Protection and Transportation Safety, China Academy of Transportation Sciences, Beijing 100029, China.
authors.forename: Jiding
authors.initials: J
authors.lastname: Chen
authors.affiliation: Laboratory of Road Ecology and Pollution Emergency Response, Research Center for Environmental Protection and Transportation Safety, China Academy of Transportation Sciences, Beijing 100029, China.
authors.forename: Yaping
authors.initials: Y
authors.lastname: Kong
authors.affiliation: Corrosion and Sustainable Infrastructure Laboratory, Western Transportation Institute and Civil Engineering Department, PO Box 174250, College of Engineering, Montana State University, Bozeman, MT 59717-4250, USA. Electronic address: xianming_s@coe.montana.edu.
authors.forename: Xianming
authors.initials: X
authors.lastname: Shi
mesh_terms: D000327:Adsorption; D003252:Construction Materials; D007700:Kinetics; D010758:Phosphorus / Q000302:isolation & purification*; D012996:Solutions; D013052:Spectrometry, X-Ray Emission; D013696:Temperature; D062065:Wastewater / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*
chemical_list: D010758:Phosphorus; D012996:Solutions; D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: Adsorption isotherms; Constructed wetland; FESEM; Mortars; Wastewater treatment; XRD