Spectroscopic characterization of organic structures and organic-inorganicinteractions in paper mill sludge

Citation
Cmbf. Maia et al., Spectroscopic characterization of organic structures and organic-inorganicinteractions in paper mill sludge, ACT HYDR HY, 28(7), 2001, pp. 372-377
Citations number
15
Categorie Soggetti
Environment/Ecology
Journal title
ACTA HYDROCHIMICA ET HYDROBIOLOGICA
ISSN journal
03234320 → ACNP
Volume
28
Issue
7
Year of publication
2001
Pages
372 - 377
Database
ISI
SICI code
0323-4320(200108)28:7<372:SCOOSA>2.0.ZU;2-Q
Abstract
The organic composition and organic-inorganic interaction in paper mill slu dge (PS) solvent extracts (hexane, ethyl acetate, acetone and ethanol) and humic fractions, humic acid (HA) and humin (HU) were studied by electron pa ramagnetic resonance spectroscopy (EPR), proton and carbon-13 nuclear magne tic resonance spectroscopy (H-1 NMR; C-13 NMR), Fourier-transformed infrare d spectroscopy (FTIR), and ultraviolet-visible spectroscopy (UV-vis). The s trategy of fractionating the PS, sequentially, with organic solvents of inc reasing polarity is a reliable analytical procedure for humic substance sam ple separation because it results in more purified fractions. FTIR, H-1 NMR and C-13 NMR results showed that hexane extract consisted mainly of alipha tic hydrocarbon structures. Their contents in the extracts decreased as the polarity of the extracting solvent increased and the content of oxygen fun ctional groups increased. Carboxylic and carboxylate functional groups were found in the acetone extract, and ester and ether functions were predomina ntly found in the ethanol extract. EPR spectra revealed some Fe3+ complexes with rhombic structure (g(1) = 4.3; g(2) = 9.0) in the humic fractions and in all solvent extracts, except hexane. Quasi-octahedral Fe3+ complexes (g = 2.3; DeltaH(pp) less than or equal to 400 G) were found in the HU fracti on and in the acetone extract. The organic free radical content in the HA f raction was higher than the non-fractionated PS sample and HU fraction.