Chemical Analysis and Molecular Models for Calcium–Oxygen–Carbon Interactions in Black Carbon Found in Fertile Amazonian Anthrosoils

Abstract

Carbon particles containing mineral matter promote soil fertility, helping it to overcome the rather unfavorable climate conditions of the humid tropics. Intriguing examples are the Amazonian Dark Earths, anthropogenic soils also known as "Terra Preta de Índio'' (TPI), in which chemical recalcitrance and stable carbon with millenary mean residence times have been observed. Recently, the presence of calcium and oxygen within TPI-carbon nanoparticles at the nano- and mesoscale ranges has been demonstrated. In this work, we combine density functional theory calculations, scanning transmission electron microscopy, energy dispersive X-ray spectroscopy, Fourier transformed infrared spectroscopy, and high resolution X-ray photoelectron spectroscopy of TPI-carbons to elucidate the chemical arrangements of calcium-oxygen-carbon groups at the molecular level in TPI. The molecular models are based on graphene oxide nanostructures in which calcium cations are strongly adsorbed at the oxide sites. The application of material science techniques to the field of soil science facilitates a new level of understanding, providing insights into the structure and functionality of recalcitrant carbon in soil and its implications for food production and climate change.

Biochar built soil carbon over a decade by stabilizing rhizodeposits

“…In this fraction, the C 1s photoelectron peak was composed of four components (Supplementary Table 10): C1s A in 284.6 eV from aromatic C (C=C); C1s B in 286.2 ± 0.2 eV, which may be assigned to phenol or hydroxyl (C-OH) groups, ether (C-O-C) or pyrrolic (C-N) groups; C 1s C in 287.5 ± 0.4 eV, assigned to carbonyl (C=O) groups; and C 1s D in 289.1 ± 0.3 eV, assigned to the carboxyl (COOH) groups 43,44 .…”

Calcium incorporation in graphene oxide particles: A morphological, chemical, electrical, and thermal study

“…Therefore we believe that Ca ions are reducing the GO-Ca containing samples mainly through epoxy functional group. Indeed, the Ca ion epoxy interaction in oxide nanographene was previously theoretical studied showing the adsorption energies of −147 kcal/mol [78,79], hence making the GO structure more stable.…”

Behavior the Water in Typical Yellow Oxisoil of Central Amazon Under Biochar Application

“…Biochar known through studies in the Amazonia Dark Earth, has been evidenced in the literature as a direct contributor in the chemical, physical and biological aspects of the soil (ARCHANJO et al, 2014;LIMA et al 2016). Due to its polycyclic aromatic chemistry, its use in soils has promoted immobilization of inorganic and organic pollutants, increased microbiological activity and greater availability of water and nutrients (LEHMANN et al, 2011).…”

“…Due to the release of volatile compounds of the biochar, micro, meso and macropores, respectively, smaller than 2.00 nm, between 2.00 nm -50.00 nm and greater than 50.00 nm originate, which interfere in the increase of their surface area, increasing water storage in their spaces (ARCHANJO et al, 2014). This effect was verified with the use of biochar in a sandy texture plintite soil by Carvalho et al (2014), where they obtained an increase of about 1% of water available to the plants at each T ha -1 of biochar.…”