“…For example, several studies have shown that the humin fraction yields higher sorption values than does its corresponding source material (Nearpass, 1976 ;Garbarini and Lion, 1986 ;Chiou et al, 2000 ;Salloum et al, 2001 ;Kang and Xing, 2005 ;Bonin and Simpson, 2007 ). Solid -state 13 C NMR studies of humin have demonstrated that humin has functional groups similar to those of the whole soil or sediment from which it was isolated; however, the humin fraction has been observed to be higher in aliphatic and substituted aliphatic carbon but lower in aromatic carbon than corresponding humic acids (Almendros et al, 1991b(Almendros et al, , 1996Nierop et al, 1999 ;Salloum et al, 2001 ;Kang et al, 2003 ;Guignard et al, 2005 ;Wang and Xing, 2005b ;Keeler et al, 2006 ;Simpson and Johnson, 2006 ;Bonin and Simpson, 2007 ). A comparison of the 13 C CPMAS NMR spectra from two types of soil and corresponding humin isolates are shown in Figure 15.8 .…”