A SEM and X-ray study for investigation of solidified/stabilized arsenic-iron hydroxide sludge.
Despite the fact that the solidification/stabilization of arsenic containing wastes with Portland cement and lime has an extensively documented history of use, the physical and chemical phenomena as a result of the interaction between arsenic and cement components have not been fully characterized. The study investigates the behavior of synthesized arsenic-iron hydroxide sludge, the by-product of arsenic removal by coagulation with ferric chloride, in solidified/stabilized matrices as well as its binding mechanisms by exploring the cementitious matrices in the micro-scale by scanning electron microscopy equipped with energy dispersive X-ray spectrometer (SEM-EDS). It was revealed that arsenic can be chemically fixed into cementitious environment of the solidified/stabilized matrices by three important immobilization mechanisms; sorption onto C-S-H surface, replacing SO4(2-) of ettringite, and reaction with cement components to form calcium-arsenic compounds, the solubility limiting phases.
Phenrat
Tanapon
T
National Research Center for Environmental and Hazardous Waste Management, Chulalongkorn University, Bangkok, Thailand.
Marhaba
Taha F
TF
Rachakornkij
Manaskorn
M
D001151:Arsenic / Q000032:analysis / Q000737:chemistry*; D003252:Construction Materials; D007501:Iron / Q000032:analysis / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D012989:Soil Pollutants / Q000032:analysis*; D018505:Waste Management; D014961:X-Ray Diffraction
D012989:Soil Pollutants; D007501:Iron; D001151:Arsenic