Batch and kinetic studies of Ni adsorption on highly humified Newfoundland peat

Metal precipitation and neutralization processes are used to treat effluents produced by the metals industry. Nickel (Ni) mining in Newfoundland and Labrador (NL) may become a source of pollution if lime precipitation techniques are used to treat effluents as an accumulation of the metal in aquatic organisms and plants may pose a health risk to humans and animals. Studies have indicated that peat can be used as a low-cost adsorbent for metals. This study investigated the kinetic and sorption equilibria parameters for the uptake of Ni with saprist NL peat. The aim of the study was to determine how the peat can be used to remove metals from the Ni mining effluents. A pseudo second order kinetic model with regression coefficients characterized kinetic parameters at a solution pH of 5.5 for peat doses of 4, 10, 21 and 40 g per litre with solution concentrations of 24, 50, 125 and 200 mg per litre. Langmuir and Freundlich isotherm equilibrium sorption parameters were determined. The study demonstrated that over 90 percent of Ni removal was obtained using the Langmuir isotherm. The adsorption process was significantly influenced by the peat dose and the initial metal concentration.12 refs., 4 tabs.