RT info:eu-repo/semantics/article T1 Efficient recovery and characterization of humic acids from municipal and manure composts: A comparative study A1 Fernández-Delgado, Marina A1 López-Linares, Juan Carlos A1 Lucas, Susana A1 García-Cubero, Mª Teresa A1 Coca, Mónica K1 Humic acids K1 Manure compost K1 Municipal mixed waste compost K1 Alkaline extraction K1 contaminants of emerging concern K1 UHPLC-MS-QTOF AB The recovery of humic acids from low-quality compost obtained in municipal solid waste treatment plants provides opportunities for its valorization. This study compares the recovery and properties of the humic acids obtained from municipal mixed waste compost (MMWC) and manure compost. The effects of temperature, time, and KOH concentration on the ratio of humic acids in the extracted liquid and the content of organic carbon of the precipitates were investigated by response surface methodology. Optimal conditions were 30°C and 24 h for both composts, with a KOH concentration of 0.53 M for MMWC and 0.25 M for manure compost. The manure compost provided a liquid extract richer in humic acids than MMWC (76.6% vs. 33.7%), but the precipitates presented similar organic carbon contents (38.1% vs. 42.4%). Regarding composition, both humic acids presented higher organic carbon and nitrogen contents than the composts used as feedstock. The extraction and further precipitation of humic acids reduced the concentration of heavy metals. Humic acids from manure compost have a slightly higher average molecular weight (2650 Da) than those from MMWC (1980 Da), while both present similar C/N ratios and degree of aromaticity. Most contaminants of emerging concern present in the original composts were not detected in the humic acids. Thus, it was demonstrated that MMWC constitutes an attractive source of humic acids with properties similar to those obtained from a high-quality compost and, therefore, with potential economic value. PB Elsevier YR 2023 FD 2023 LK https://uvadoc.uva.es/handle/10324/66595 UL https://uvadoc.uva.es/handle/10324/66595 LA eng NO Waste Management 172 (2023) 245–255 NO Producción Científica DS UVaDOC RD 28-nov-2024