Case Number 106035 - Novel Mercury (and other metal) Vapor Sorbents
Contact: Doug Nienaber
Description: Dr. Neville Pinto and his laboratory have developed a material to remove metal vapors from gas streams, particularly mercury.
Coal-fired power plants are the largest single man-made source of mercury pollution in the U.S. (approximately 48 tons of mercury annually, or about one-third of the total US anthropogenic mercury emissions). Mercury from coal-fired power plants is released into the air through the exhaust system when coal is burned. The primary exposure occurs when this mercury falls to the earth and runs into lakes, rivers, and streams and contaminates the fish, which subsequently contaminates humans when they eat these fish and shellfish. Coal-fired power plants also produce fly ash; the EPA has in recent decades required that fly ash be captured prior to release. This fly ash is also contaminated with mercury. Currently coal-fired power plants have taken to use activated carbon to trap mercury emissions. Activated carbon, often impregnated with iodine or sulfur, is widely used to trap mercury emissions from coal fired power stations, medical incinerators, and from natural gas at the wellhead.
UC has developed a sorbent that captures mercury for use in a coal-fired power plant. The UC sorbent can be produced from commercially available raw materials without the need for any exotic chemistry. This sorbent consists of a base of silica which has been functionalized and coated. The coating is a chemically active environment for reaction with mercury vapor. UC has observed Hg(II) capacity of up to 58 mg/g adsorbent at 160°C and thermal stability up to 200°C in lab testing (miligram quantities). UC is currently testing the sorbent (hundred gram quantities) in an EPA test facility in Research Park Triangle, NC. Based on UC's research the sorbent will cost less than activated charcoal (approximately 70-90% less). In addition the technology is greener because it minimizes secondary wastes and secondary emissions as well as reducing the amount of contamination in fly-ash. The sorbent also has the capability to be adapted to being used for other metal vapors, such as lead, zinc and cadmium.
In conclusion, UC investigators have developed a novel sorbent to remove mercury from flu gas which has high selectivity for mercury (both Hg(II) and Hg0), is capable of extended operation, minimizes secondary wastes and secondary emissions, costs less than $1000/lb Hg.
There is a patent pending, US Serial No. 11/550,927 entitled "High capacity materials for capture of metal vapors from gas"