Chemical equilibrium calculation for evaluating the buffering capacity of acidic natural water equilibria with the mineral phase gibbsite

Abstract

A simple computer model based on the chemical equlibrium calculation is developed to evaluate the buffering capacity, β, of acidic natural water equilibria with the mineral gibbsite. The influence of various factors [temperature, equilibrium constant for solubility of Al(OH)₃ solid-phase K_sp, concentrations of fluoride, dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC)] on the β values calculated were investigated. This model has been tested with real water quality data and applied to the practical analysis of natural water samples. The uncertainties in theoretical calculation of buffering capacity associated with the errors from variations in thermodynamic constants and measured input data were evaluated by the Monte Carlo method.