Sorption of Metals and Organic Contaminants to Biochar.

Production of bioenergy creates a biocharcoal byproduct which may have potential for use as a soil amendment to sequester a range of anthropogenic inorganic and organic contaminant. Biochar soil amendments are commonly proposed as a means to improve soil fertility, water holding capacity, sequester soil carbon, and reduce greenhouse gasses. In this study, the potential for biochar to bind heavy metals (Cd, Pb, Ni,Cu), organic contaminants (pharmaceuticals), and dissolved organic matter (DOM) have been evaluated. The ability of biochar to bind DOM may have significant implications for the stabilization of biochar in soil and its ability to sequester C. In addition, if biochar has a high binding capacity for heavy metals and organic contaminants it could be a useful addition to land applied biosolids. Batch sorption experiments have been conducted using walnut shell biochar (900° C), wood biochar (700 and 900° C), activated carbon, and kaolinite. Results show that the walnut shell biochar and activated carbon both have very high binding capacity for all heavy metals (Cu in particular) and compost extracted DOM. Experiments are ongoing to evaluate sorption parameters for a wide range of pharmaceuticals commonly found in municipal biosolids.