waHat is abiotic reactions
Answers
Explanation:
Clay minerals are the major binding partners of organic matter in soils. Furthermore, these minerals show a broad spectrum of chemical reactivity. Besides the biotic pathways, these abiotic reaction potentials should be considered when investigating chemical processes in soils, such as genesis of humic substances and binding and transformation of xenobiotic substances. For mechanistically oriented laboratory experiments, it is practicable, due to the complexity of soil organic matter, to use simple organic compounds, i.e., aromatic constituents of lignin or humic acids. Therefore, in our work, phenols such as catechol, pyrogallol and 2,6-dimethylpenol were used to investigate their reactions on the surface of montmorillonite particles. Several reaction products containing quinonoid, carboxylic and carbonylic groups could be determined. In addition, the colored synthetic reaction products could not be removed from the mineral surfaces by organic solvents. We conclude that oxidation of the phenols is the first step in their transformation. This is followed by polymerization of the oxidation products. In order to elucidate the mechanisms of the catalytic activities, the surfaces of the clay particles were examined with a scanning electron microscope (SEM), coupled with an energy dispersive x-ray spectometry (EDX). In the vicinity of iron-rich iron domains of the clay surfaces, synthetic organic coatings were observed. We conclude that iron in the mineral structure is partially responsible for the catalytic activity of clays. To obtain structural information about the developed reaction products, infrared-spectrometry (FTIR), liquid 13C-nuclear magnetic resonance spectrometry (NMR) and matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF-MS) were used.