Wetting properties of poultry litter and derived hydrochar

Abstract

Detailed assessment of hydrochar wetting properties, which could provide an essential understanding of underlying mechanisms during its application to soils, is lacking. We characterized hydrochar produced from hydrothermal carbonization (HTC) performed on poultry litter at various temperatures and for different times in terms of hydrophobicity and surface free energy properties. Hydrochar was more hydrophobic than untreated poultry litter, and its hydrophobicity increased with increasing HTC temperature (contact angle > 130°). These changes were correlated with degradation of hemicellulose and cellulose. Hydrochar produced at 250°C contained mostly lignin and displayed high hydrophobicity over both prolonged wetting periods and repeated wetting cycles. Surface free energy was calculated using the Owens–Wendt–Rabel–Kaelble and Wu models, with the latter resulting in lower standard errors. The surface free energy decreased as HTC treatment severity increased from 26 mJ/m2 in the poultry litter to 8 mJ/m2 after treatment at 250°C for 60 min. The dispersive component fraction of the surface free energy increased with increasing treatment severity. This study demonstrated that changes in the physical composition of hydrochar due to increased treatment severity increase its hydrophobicity and decrease its surface free energy. Moreover, due to non-persistent hydrophobicity, hydrochar produced at temperatures lower than 250°C will likely not show adverse effects on soils.

Using the Aqueous Phase Produced from Hydrothermal Carbonization Process of Brown Seaweed to Improve the Growth of Phaseolus vulgaris

“…Among these, different research works focused on the toxicity of AHL on seed germination. In some of these studies, AHL was mixed with other substrates as the hydrochar itself [ 32 , 33 , 34 , 35 ]. Most recently, Celletti et al [ 23 ] tested the effects on the growth of a whole Zea mays plant using diluted AHL solutions as a hydroponics medium.…”

Valorization of the poultry litter through wet torrefaction and different activation treatments

“…At elevated temperatures, the hydroxyl ions of the activation agent are able to react with heteroatoms in the carbonaceous structure. This leads to the release of heteroatoms from the structure in the form of volatiles or easy soluble compounds and consequently increases the carbon content in the processed material (Mau et al, 2018). Silica-alumina can be one of the major compounds that are part of the mineral matter of PL (Shankar Pandey et al, 2019).…”