1. The Charles E. Via Jr. Department of Civil and Environmental Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0246, Center for NanoBioEarth, Department of Geosciences, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0420, and Surface Analysis Laboratory, Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061-0001