KNOXVILLE - Researchers from a laboratory in Tennessee have discovered a new method for removing carbon dioxide from ambient air while conducting a study that was intended to help remove contaminants from water. According to a news release by Oak Ridge National Laboratory, the new method is simple and reliable. The discovery is being billed as a new option to capture and store carbon and help combat global warming. Scientists at the lab in Oak Ridge, Tenn., discovered the new method while trying to use a compound called guanidine to remove contaminants such as sulfate, chromate and phosphate from water. Radu Custelcean, a research scientist at the lab, said in a release that after exposing a