Revisiting Structural Insights Provided by Analytical Pyrolysis About Humic Substances and Related Bio- and Geo-Polymers

Progress achieved in the knowledge of the structure and composition of humic substances and related forms of natural organic matter (composted or charred biomass, black carbon, etc.) by the use of analytical pyrolysis and related techniques is reviewed. It is suggested that the fingerprinting potential of pyrolytic techniques, when the results are processed from appropriate ‘pyronomic’ approaches, may lead to unbiased and operative insights on the functional relationships in recalcitrant C forms as well as to a successful quantitative monitoring of various environmental impacts. On the other hand, classical experimental limitations associated to the low, sample-dependant, yields of pyrolytic compounds and the coexistence of molecular assemblages from different origin (i.e. thermoevaporation products, thermally altered products and rearrangement products) can be in several cases managed by sequential degradation strategies. In addition, suitable multivariate data treatments can be applied to remove spurious information and to identify compound patterns with improved discriminating potential as regards structural features of humic-type macromolecules and related bio- and geo-polymers.