Impact of Feedstock on Biochar Surface Properties: Practical Application of Boehm’s and Potentiometric Titration

Biochar is a material created through the pyrolysis of different kind of biomass. On the basis of last research reports, it was found, that the kind of used biomass influences on surface properties of biochar. These properties are of key importance in effectiveness of biochar as a soil sorbent.

The experiments were carried out using three biochars derived from: tobacco, sweet corn cobs and vineyard which are produced by the "double-barrel" method.

The aim of the research was an investigation the effects of feedstock kind on surface properties of biochar. The characteristics of selected surface properties of biochar included the determination of: functional group content by Boehm's acid-base titration method; determination of the variable surface charge and distribution of surface functional groups from potentiometric titration.

Biochar samples exhibit a high variable surface charge (Q) and content of surface functional groups. Tobacco has the highest Q and content of acidic groups, while sweet corn cobs - the lowest one. Variable surface charge provides information about the quantity of surface functional groups. The distribution of surface functional groups exhibits the existence of 3 peaks, which indicate the presence of acidic groups (carboxylic, lactonic and phenolic).

The biochar from tobacco, vineyard or sweet corn cobs possessed merit for the improvement pollution removal from soil.

Research was conducted under the project "Water in soil - satellite monitoring and improving the retention using biochar" no. BIOSTRATEG3/345940/7/NCBR/2017 which was financed by Polish National Centre for Research and Development in the framework of "Environment, agriculture and forestry" - BIOSTRATEG strategic R&D programme