Please use this identifier to cite or link to this item:
Title: Hydrophobicity and surface free energy to assess spent coffee grounds as soil amendment. Relationships with soil quality
Authors: Cervera-Mata A
Aranda V
Ontiveros -Ortega A
Comino F
Martin-García JM
Vela-Cano M
Delgado G
Abstract: The aim of this work was to evaluate the effects of spent coffee grounds (SCG), a highly hydrophobic raw material, on the hydrophobicity of two Mediterranean agricultural soils. Physical, chemical, mineralogical and biological soil properties, most of them used to evaluate soil quality, were studied and related to the main hydrophobicity parameters. The in vitro assay was performed with two SCG doses (2.5 and 10%), two soils and two incubation times (30 and 60 days). Hydrophobicity was determined by the water drop penetration time test (WDPT), the contact angle (CA) with H2O, formamide and diiodomethane, and the surface free energy components (SFE) calculated using the Van Oss model. The addition of SCG increased the WDPT, CA and SFE, being the latter which was related to a greater number of soil quality variables. Hydrophobicity was related to lower humus quality index (HQI), and a higher proportion of labile organic matter, as shown by Infrared and UV–vis spectroscopy. An increase in hydrophobicity was related to an improvement of soil physical quality: a high aggregate stability index, saturated hydraulic conductivity, porosity (total and macro), water retention, and a less bulk density. The most critical effect related to the increase in hydrophobicity was the significant decrease in the available water content. The SEM images showed a greater occlusion and stabilization mechanism of the SCG particles incorporated in Vega soil, probably due to its higher content of smectite and carbonates. The appearance of fungal biomineralizations of calcium carbonate is associated with SCG addition and could be considered as an interesting and little studied process of inorganic carbon fixation and secuestration. These results showed that hydrophobicity can afford relevant information that can help to asses soil quality status after an amendment with SCG.
Keywords: Soil hydrophobicity
Surface free energy
Organic amendments
Soil hydrophobicity Surface free Waste management Organic raw material
Issue Date: Jan-2021
metadata.dc.description.sponsorship: This work was supported by project AGL2014-53895-R from the Spanish Ministry of Economy and Competitiveness and by the European Regional Development Fund (FEDER). Authors are also grateful to PAIDI funding for research groups RNM-127 and FQM-363. We also thank technical support provided by the Universidad de Jaén and Scientific-Technical Instrumentation Center (Funding by Universidad de Jaén, MINECO, Junta de Andalucía and FEDER). This paper will form part of Ana Cervera-Mata’s doctoral thesis,
Publisher: Elsevier
Citation: Cervera-Mata A
Appears in Collections:DF-Artículos

Files in This Item:
File Description SizeFormat 
catena2021.pdf3,47 MBAdobe PDFView/Open

This item is protected by original copyright