TY - JOUR

T1 - Hydrothermal carbonization and pyrolysis in wetland engineering

T2 - Carbon sequestration, phosphorus recovery, and structural characterization of willow-based chars with X-ray μ-computed tomography

AU - Acosta, Andrés C.

AU - Arias, Carlos A.

AU - Biller, Patrick

AU - Wittig, Nina K.

AU - Baragau, Ioan Alexandru

AU - Alhnidi, M. Jamal

AU - Ravenni, Giulia

AU - Sárossy, Zsuzsa

AU - Benedini, Lidia

AU - Abramiuc, Laura Elena

AU - Popescu, Dana Georgeta

AU - Negassa, Wakene

AU - Marulanda, Victor F.

AU - Müller-Stöver, Dorette S.

AU - Brix, Hans

N1 - Funding Information: Andr\u00E9s C. Acosta thanks Aidan Mark Smith for the kind tutorship during HTC experiments and acknowledges part of the funding through the Ministry of Science and Technology of Colombia grant no.885. Use of the Novo Nordisk Foundation research infrastructure AXIA (grant NNF19OC0055801 ) is gratefully acknowledged. The European Commission supported this research through grant no.821410 (PAVITR project) and LIFE INTEXT (LIFE18 ENV/ES/000233). Ioan-Alexandru Baragau, Laura Elena Abramiuc, and Dana Georgeta Popescu acknowledge the funding through the Core Program of the National Institute of Materials Physics, granted by the Romanian Ministry of Research, Innovation and Digitization ; Project PC3-PN23080303 Publisher Copyright: © 2024 The Author(s)

PY - 2024

Y1 - 2024

N2 - Willows from engineered wetland systems (EWS) offer a sustainable approach to wastewater treatment and biomass production. Our study assesses their potential for nutrient recovery and carbon sequestration using slow pyrolysis (600 °C) and hydrothermal carbonization (250 °C). Here, we propose EWS-pyrochars as a ready-to integrate opportunity for soil amendment, as they exhibit a predominant CO2 release and the absence of harmful compounds in pyrolysis-chromatograms, indicating higher stability than hydrochars. Using sequential P-extractions, we observed a high bioavailability in the willow-woodchips and a significant P-retention in EWS-chars—up to 92 % in pyrochars and near-complete retention in hydrochars, along with a higher labile-P fraction of 21 % in hydrochars than 5 % in pyrochars. Utilizing X-ray-based techniques, Raman spectroscopy, scanning electron microscopy, and gas physisorption, we characterized the EWS-chars' structures. We revealed innovative 3D-visualizations, which transcend previous literature by providing insights into the chars' internal porosity and quantifying, for the first time, their carbonaceous structural thickness via a meshing algorithm and the mean Feret diameter. EWS-pyrochars exhibit remarkable aromaticity with a higher concentration of overall sp2 C-atoms at 63 % vs. 43 % in hydrochars. Moreover, unlike hydrochars, which depict occluded porosity, EWS-pyrochars exhibited 92 % water storage-like pores. Although hydrochars indicated lower carbonization and thermal stability than pyrochars, their higher carbon retention (55 vs. 41 % in pyrochar) suggest superior annual benefits—on a 10 ha EWS scale—of 80-tons of carbon sequestration and 334 kg of phosphorus recovery versus 60-tons of carbon and 298 kg of phosphorus with pyrochars. Our findings suggest innovative materials for resource recovery, advancing the engineered wetland systems field, shifting their traditional use, and opening the opportunity for future integration into biorefineries.

AB - Willows from engineered wetland systems (EWS) offer a sustainable approach to wastewater treatment and biomass production. Our study assesses their potential for nutrient recovery and carbon sequestration using slow pyrolysis (600 °C) and hydrothermal carbonization (250 °C). Here, we propose EWS-pyrochars as a ready-to integrate opportunity for soil amendment, as they exhibit a predominant CO2 release and the absence of harmful compounds in pyrolysis-chromatograms, indicating higher stability than hydrochars. Using sequential P-extractions, we observed a high bioavailability in the willow-woodchips and a significant P-retention in EWS-chars—up to 92 % in pyrochars and near-complete retention in hydrochars, along with a higher labile-P fraction of 21 % in hydrochars than 5 % in pyrochars. Utilizing X-ray-based techniques, Raman spectroscopy, scanning electron microscopy, and gas physisorption, we characterized the EWS-chars' structures. We revealed innovative 3D-visualizations, which transcend previous literature by providing insights into the chars' internal porosity and quantifying, for the first time, their carbonaceous structural thickness via a meshing algorithm and the mean Feret diameter. EWS-pyrochars exhibit remarkable aromaticity with a higher concentration of overall sp2 C-atoms at 63 % vs. 43 % in hydrochars. Moreover, unlike hydrochars, which depict occluded porosity, EWS-pyrochars exhibited 92 % water storage-like pores. Although hydrochars indicated lower carbonization and thermal stability than pyrochars, their higher carbon retention (55 vs. 41 % in pyrochar) suggest superior annual benefits—on a 10 ha EWS scale—of 80-tons of carbon sequestration and 334 kg of phosphorus recovery versus 60-tons of carbon and 298 kg of phosphorus with pyrochars. Our findings suggest innovative materials for resource recovery, advancing the engineered wetland systems field, shifting their traditional use, and opening the opportunity for future integration into biorefineries.

KW - Carbon sequestration

KW - Engineered wetland systems

KW - Hydrothermal carbonization

KW - Phosphorus recovery

KW - Pyrolysis

KW - X-ray micro-computed tomography

KW - Carbon sequestration

KW - Engineered wetland systems

KW - Hydrothermal carbonization

KW - Phosphorus recovery

KW - Pyrolysis

KW - X-ray micro-computed tomography

U2 - 10.1016/j.cej.2024.151916

DO - 10.1016/j.cej.2024.151916

M3 - Journal article

AN - SCOPUS:85193201093

VL - 492

JO - Biochemical Engineering Journal

JF - Biochemical Engineering Journal

SN - 1369-703X

M1 - 151916

ER -