Study of the humic-like compounds formed from L-tyrosine on homoionic clays

Abstract

The ability to produce humic-like polymeric compounds, with L-tyrosine as the starting material, was evaluated using different mineral systems, e.g. on Ca-, A1-and Cu(II)-saturated montmorillonite, nontronite and kaolinite, and on quartz. Clay minerals proved to be effective in the formation of these compounds, but not quartz, except in the presence of Cu(II). The newly formed compounds were fractionated by alkaline extraction. With clay systems, the amounts of substances produced appear to be related more to the interlayer cation than to the clay type. Copper cations appear to be more effective when not associated with the clay structure.

Mineral Surface Control of Organic Carbon in Black Shale

“…Two signals for the cyclopentadienyl (Cp) ligands were observed for the cis-isomers, whereas the Cp ligands are magnetically equivalent in the trans-isomers. A butatriene with tert-butyl groups, (Z)-2,2,7,7-tetramethyl-3,4,5-octatriene (1b) (21), also gave the zirconacyclopentyne 2b after 1 hour at rt (yield 90% by 1 H NMR, cis/trans ϭ 66/34), and the cis/trans ratio reached 12/88 after 48 hours.…”

“…This finding implies that OM is present dominantly within smectite interlayer sites. Many types of polar or charged molecules enter interlayer sites from aqueous solution (17,18), including atrazine (19), humic acid (20,21), and proteins (22,23). The last two groups are readily available in soil and marine environments (24,25).…”

In situ ATR-IR investigation of L-lysine adsorption on montmorillonite

“…For example, the biological degradation rates of amino acids are decreased if they are adsorbed on clay minerals [7][8][9], which has significant impacts for the nitrogen cycle in soils [9]. The hydrothermal stability [10] and reactivity [11,12] of amino acids are also known to be substantially affected by their adsorption on clay minerals.…”

Formation Mechanisms of Humic Substances in the Environment

“…Condensation of glucose and tyrosine/glycine/ tryptophan at 70 ° C: FTIR spectra resembling natural humic substances; yields of humic substances; XRD investigation into change in d -spacings Arafaioli et al (1997Arafaioli et al ( , 1999 ; Bosetto et al (1995Bosetto et al ( , 1997Bosetto et al ( , 2002 Smectites Condensation of arginine and glucose at 37 ° C; C and N fractions yields; FTIR spectra of solid residue and supernatant humic substances; XRD investigation into change in d -spacings Gonzalez and Laird (2004) …”