Understanding the complex and dynamic metal-biochar interactions under natural settings is of great relevance to the application of biochar for environmental remediation and soil amendment. To find the optimal biochar for above-mentioned applications, extensive research has been devoted to study the interactions between metal and biochar. However, a thorough understanding of the interaction mechanism and how the interactions change in the biochar-soil environment over time is missing. In the present study, we characterize the interaction between zinc and biochars prepared from wheat straw and sludge, and incubate the zinc-loaded biochars with zinc-limited soils of different properties (e.g., pH and mineralogy). Zinc adsorption capacity and binding thermodynamics are measured using batch adsorption and flow adsorption microcalorimetry. The retention of zinc in the biochars and mobilization of zinc to soil are quantified by inductively coupled plasma mass spectrometry (ICP-MS). The speciation of zinc on biochars and soil is characterized by X-ray adsorption spectroscopy. Preliminary results suggest that the affinity of zinc varies between different biochars, due to different surface chemistries on biochars. The relative mobility of zinc is found to be dependent on the binding affinity and solution chemistry.

Speciation dynamics of metal at biochar-soil interface: Effects of biochar and soil properties

249th National Meeting (2015)

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