Metal removal from wastewater using peat

Peat has been investigated by several researchers as a sorbent for the capture of dissolved metals from wastestreams. Besides being plentiful and inexpensive, peat possesses several characteristics that make it an effective media for the removal of dissolved metal pollutants. The mechanism of metal ion binding to peat remains a controversial area with ion-exchange, complexation, and surface adsorption being the prevalent theories. Factors affecting adsorption include pH, loading rates, and the presence of competing metals. The optimum pH range for metals capture is generally 3.5–6.5. Although the presence of more than one metal in a solution creates competition for sorption sites and less of a particular ion may be bound, the total sorption capacity has been found to increase. Studies have also shown that metals removal is most efficient when the loading rates are low. In addition, recovery of metals and regeneration of the peat is possible using acid elution with little effect on peat’s sorption capacity.