Detail publikace

Role of polar and apolar moieties in water adsorption by humic acids under arid conditions

Fashina, Bidemi Novak, Frantisek Kucerik, Jiri

Originální název

Role of polar and apolar moieties in water adsorption by humic acids under arid conditions

Typ

článek v časopise ve Web of Science, Jimp

Jazyk

angličtina

Originální abstrakt

In arid soils, humic acids (HAs) are used as amendments to improve water uptake from the atmosphere. This method of harvesting water involves several steps depending on the relative humidity (RH). At low RH, water is adsorbed solely on primary sorption sites such as polar groups. As RH increases, more water is adsorbed on polar groups forming secondary sorption sites, which grow as the RH increases. As a result, the neighboring sorption sites can connect to form water molecule bridges (WaMBs). The WaMBs are responsible for the transport of water in the form of clusters into hydrophobic pores resulting in an increase in water content in organic matter (OM), swelling of OM and formation of phase water. HA being a complex mixture complicates the understanding of the relationship between the proportion of polar groups and properties of water. The understanding of these relationships can guide the design of humic-based amendments applicable in arid systems. To address this issue, seven HAs were characterized by nuclear magnetic resonance followed by the investigation of the properties of water (water content, strength of WaMBs and strength of water binding) on the HAs. Results showed that the content of polar groups positively correlated with the amount of water adsorbed by HA and the stability of WaMBs. It was found that presumably apolar moieties such as aromatics and phenols increased the binding energy of water to HA thereby appearing to be responsible for preventing the desiccation. In addition, between 44 and 76% RH, the WaMB stability positively correlated with O-alkyl and peptides moieties. Therefore, both polar and apolar domains influence water properties depending on RH. We conclude that this synergism is an advantage in systems composed of hydrophobic and hydrophilic molecules held together by weak interactions providing high flexibility to the system under arid conditions.

Klíčová slova

Humic acid; Hydration; Desiccation; C-13 NMR; DSC; Water molecule bridges

Autoři

Fashina, Bidemi; Novak, Frantisek; Kucerik, Jiri

Vydáno

22. 9. 2021

Nakladatel

SPRINGER

Místo

DORDRECHT

ISSN

1388-6150

Periodikum

Journal of Thermal Analysis and Calorimetry

Ročník

145

Číslo

1

Stát

Maďarsko

Strany od

3031

Strany do

3039

Strany počet

9

URL

https://link.springer.com/article/10.1007/s10973-020-09964-6

BibTex

@article{BUT170303,
  author="Fashina, Bidemi and Novak, Frantisek and Kucerik, Jiri",
  title="Role of polar and apolar moieties in water adsorption by humic acids under arid conditions",
  journal="Journal of Thermal Analysis and Calorimetry",
  year="2021",
  volume="145",
  number="1",
  pages="3031--3039",
  doi="10.1007/s10973-020-09964-6",
  issn="1388-6150",
  url="https://link.springer.com/article/10.1007/s10973-020-09964-6"
}