Determination of Sources of Organic Matter in Solid Waste by Analysis of Phenolic Copper Oxide Oxidation Products of Lignin

Abstract

The decomposition behavior of lignocellulosic materials is related to the taxonomic classes of the parent plant tissues. Thus, methods to characterize the composition of mixtures of lignocellulosic materials such as municipal solid waste (MSW) according to different taxonomic classes of plants are useful. The copper oxide (CuO) oxidation products of lignin provide molecular markers that allow for characterization of the initial plants. The objective of this study was to determine if the chemical composition of the monomers present after CuO oxidation can be used to infer information on the content of woody angiosperms (hardwood—HW), non-woody angiosperms (leaves and grasses—LG), woody gymnosperms (softwood—SW), and non-woody gymnosperms (needles—GN). Results showed that the composition of HW and SW in synthetic mixtures can be estimated from CuO oxidation products of lignin within an error of ±60% of the expected values. The high uncertainty in the estimate of composition in synthetic mixtures can be attributed to the fact that the components selected for the synthetic mixtures had different CuO oxidation products compared to the average which was used in developing the mixing model. Application of the mixing model to estimate the composition of samples from a Kentucky (KY) landfill showed that the majority of the samples are from HW and SW with little to no non-woody tissues (LG, GN). However, the mixing model is not sufficiently precise to infer more detailed information on MSW composition.