GREENSBORO, North Carolina, Nov. 19 -- The University of North Carolina Greensboro campus issued the following news: Biochar, a centuries-old technology for enriching depleted agricultural soils, has been getting second looks in recent years as a potential solution to a range of challenges, from making fire-resistant building materials to storing carbon from the atmosphere. At UNC Greensboro, Jianjun Wei is researching ways to make it better at removing lead, mercury and other heavy metals, plu  more