Peat Characterization and Uptake of Nickel (II) and Cobalt (II) in a Saprist Peat Column

Abstract

In this study, fibrist and saprist sphagnum peat soils taken from a bog in Torbay, Newfoundland (Canada) were characterized. The saprist and fibrist peat soils had wet bulk densities of 0.65 and 0.60 g/cm 3 , respectively, and cation-exchange capacities of 70 and 45 meq/100 g, respectively. The pH of both peat soils was 4.2 and the soils were amorphous for the most part; however, the fibrist peat was more porous than the saprist peat. Results of Fourier transform infrared spectroscopy and 13 carbon nuclear magnetic resonance suggested the presence of carboxylic acid, alcoholic hydroxyl, phenolic hydroxyl, amine and amide functional groups in both peats. The less reported amine and amide groups may have been observed because non-destructive characterization techniques were employed. The saprist peat was studied as an Ni 2+ and Co 2+ adsorbent in a vertical downflow fixed-bed column and at the end of each column experiment, metal ions in the upper layer of the peat were desorbed with HCl. The metal sorption capacity of the saprist peat increased with decreasing flow rate and overall the sorption capacity of Ni 2+ was two times greater than the sorption capacity of Co 2+ . Ni 2+ may have been retained by a combination of ion exchange and complexation, while Co 2+ may have been retained only by complexation.