Removing Heavy Metals
Many industrial processes produce significant amounts of effluent containing heavy metals. Heavy metals are known to cause several health effects in humans and other living organisms. It is therefore necessary to remove heavy metals from waste water before it is returned to the water supply. Heavy metals can be removed from waste water through a variety of methods. Current methods, such as filtering, precipitation and ion exchange, are very expensive. The SORPMET project was undertaken by a group of European companies to identify and test new, cheaper methods of heavy metal removal. The study focused on four heavy metals: chromium, copper, nickel and zinc. Inexpensive minerals that occur naturally throughout Europe were investigated for their cleansing potential using the sorption method. Sorption removes heavy metals from the waste water stream through both absorption and adsorption. Several minerals were identified with high sorption capacity, removing up to 200 mg of metal per gram of sorbent. In addition, the partners experimented with inexpensive chemical treatments to boost the minerals' capacity for removal. It was found that the small improvement in sorption capacity did not justify the added cost. Prototypes were developed for different industrial applications. Several installations have already been made at Italian factories. Currently, the partners are analysing the latest results before moving forward to commercial exploitation. The results will promote cleaner, more competitive industry across Europe.
