Analytical and Spectroscopic Characteristics of Refuse Compost-Derived Humic Substances

Abstract

Animal manure composts contain a substantial amount of organic matter, subse- quently containing a significant amount of humic substances. In this study, we investigated the yields of refuse compost-derived humic substances and their analytical and spectroscopic charac- teristics. The humic acid (HA) and fulvic acids (FAs) of humic substances were extracted from refuse compost and purified. The composition of humic substances were determined by elemen- tal analysis and that of functional groups by Fourier transform infrared spectroscopy (FTIR) and solid-state 13 C nuclear magnetic resonance spectroscopy with cross-polarization and magic-angle spinning (CPMAS 13 C NMR). Elemental analysis indicates that C and N contents of HA surpass those of FAs. However, total functional group acidities of FAs were much greater than that of HA. Both FTIR and 13 C NMR spectra indicate that carboxyl contents of FAs surpass that of HA. The characteristics of compost-derived humic substances affects their reactions with metals es- pecially heavy metals, which in turn affects the mobility and biotoxicities of heavy metals in soil and the associated environments.