Fixation of chromium and arsenic in a contaminated South Florida calcareous and organic soil mixture, with Portland cement

Portland cement was evaluated as a fixation agent for a South Florida toxic soil mixture containing Chromium and Arsenic. Metal extraction assessment focused timely patterns of: concentration, solid loadings, effective diffusivities, and leachability indexes for three scaled preparations and controls, following Atomic Absorption Spectrometry (A) on leachates and Scanning Electron Microscopy (SEM) matrix views. Fixation abated leaching Arsenic; released Chromium three folded Arsenic, yet non-toxic; sequential leaching and the EP toxicity test, rendered lower than 0.1 per cent, and less; year-round leaching matched the 24-hour EP test desorptions often. SEM suggested impact of diverse cement-soil matrices upon kinetics. Leaching Arsenic fitted a diffusion for semi-infinite particles, with initial lag. Correlated desorptions for Chromium, prescribed another model. Diffusion coefficients for Arsenic in weekly and monthly extractions, significantly overlapped. Adequacy of evaluated random error was confirmed by predicted observations. Cement detoxified the soils; no scaled preparation worked better than others tested