SOLID-STATE, 13C, CROSS-POLARIZATION, “MAGIC-ANGLE” SPINNING, NMR SPECTROSCOPY STUDIES OF SEWAGE SLUDGE

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Abstract
Using 13C, solid-state NMR, we examined sludges and composts obtained from varied locations. A minimum of sample preparation is required with this technique. The samples are simply dried and ground before they are packed into the rotor. The spectra of the sewage sludges examined are composed of four broad envelopes of chemical shifts representative of carbonyl carbon, aromatic carbon, aliphatic carbon adjacent to -OH or -N, and aliphatic carbon. The intensities of the carbonyl carbon, aliphatic carbon adjacent to -OH and -N and aliphatic carbon resonances were less in the compost spectra, when compared with the intensity of the aromatic carbon resonances, than in the sewage sludge spectra. Spectra of four reference compounds (stearic acid, cellulose, lignin, and protein (keratin)) are included to assist in the interpretation of the sample spectra. Interrupted decoupling experiments were conducted to simplify these complex spectra and estimate the amount of nonprotonated (branched and carbonyl) carbon they contain. This preliminary solid-state, NMR study of sludges demonstrates that this technique is an effective tool for studying these complex systems.