Molecular understanding of speciation transformation of phosphorus and sulfur in food waste digestate during hydrothermal treatment.
Waste Manag
; 190: 55-62, 2024 Sep 13.
Article
en En
| MEDLINE
| ID: mdl-39276505
ABSTRACT
Recovering phosphorus (P) and sulfur (S) from biowaste is a key strategy to address the current P resources shortage and soil S deficiency. Food waste digestate (FWD) contains high contents of P and S, while its direct application is severely limited by available nutrient leaching loss and pollutant exposure. Hydrothermal treatment (HT) is an effective technique for biowaste disposal, enabling detoxification and resource recovery. The study systematically investigated the speciation transformation of P and S in FWD during HT, using chemical extraction and in-situ X-ray absorption near-edge structure (XANES) spectroscopy. The results revealed that up to 98% of P in FWD was enriched in the solid product (hydrochar) after HT, with organic P and labile P being converted into stable Ca-bound forms, predominantly hydroxyapatite. This transformation reduced the risk of P leakage loss compared to untreated FWD. Interestingly, the S speciation evolution exhibited more complexity. The highest S proportion in hydrochar of 73.6% was observed at 140 °C under HT. As the temperature increased from 140 °C to 180 °C, S in the hydrochar gradually dissolved into the liquid phase, attributed to unstable aliphatic compounds (mercaptan) and the sulfides oxidizing to sulfates. Above 180 °C, intermediate oxidation states and sulfates were reduced and formed metal sulfides. These findings have important implications for understanding the viability of HT for FWD disposal and the value-added utilization of FWD.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Idioma:
En
Revista:
Waste Manag
Asunto de la revista:
SAUDE AMBIENTAL
/
TOXICOLOGIA
Año:
2024
Tipo del documento:
Article
País de afiliación:
China
Pais de publicación:
Estados Unidos