The objective of the present study was to assess major chemical reactions and chemical forms contributing to solubility and speciation of Fe(II), Co(II), and Ni(II) during anaerobic digestion of sulfur (S)-rich stillage in semi-continuous stirred tank biogas reactors (SCSTR). These metals are essential supplements for efficient and stable performance of stillage-fed SCSTR. In particular, the influence of reduced inorganic and organic S species on kinetics and thermodynamics of the metals and their partitioning between aqueous and solid phases were investigated. Solid phase S speciation was determined by use of S K-edge X-ray absorption near-edge spectroscopy. Results demonstrated that the solubility and speciation of supplemented Fe were controlled by precipitation of FeS(s) and formation of the aqueous complexes of Fe-sulfide and Fe-thiol. The relatively high solubility of Co (∼ 20% of total Co content) was attributed to the formation of compounds other than Co-sulfide and Co-thiol, presumably of microbial origin. Nickel had lower solubility than Co and its speciation was regulated by interactions with FeS(s) (e.g. co-precipitation, adsorption, and ion substitution) in addition to precipitation/dissolution of discrete NiS(s) phase and formation of aqueous Ni-sulfide complexes.
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http://dx.doi.org/10.1016/j.jhazmat.2014.01.051 | DOI Listing |
Mol Pharm
January 2025
Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, St. John's University, 8000 Utopia Parkway, Queens, New York 11439, United States.
Although glycine is the simplest of the amino acids, its solution and solid-state properties are far from straightforward. The aqueous solubility of glycine plays an important role in various applications, including nutrition, food products, biodegradable plastics, and drug development. There is evidence that glycine in subsaturated pH 3-8 solutions forms a dimer, as suggested by several techniques.
View Article and Find Full Text PDFChemosphere
January 2025
Faculty of Agronomy and Veterinary Medicine, University of Brasília, 70910-970, Brasília, Federal District, Brazil.
Phosphorus (P) plays an essential role for plant growth, but conventional P sources used in agriculture are finite and non-renewable. As a result, there is a growing need to explore alternative P sources such as sewage sludge (SS) - a P-rich solid waste and valuable renewable resource that is often mismanaged globally. Pyrolysis is a promising technique for managing SS.
View Article and Find Full Text PDFEnviron Res
December 2024
Engler-Bunte-Institut, Water Chemistry and Water Technology, Karlsruhe Institute of Technology, Engler-Bunte-Ring 9, 76131, Karlsruhe, Germany.
This study reviewed the recovery of humic substances (HS) from anaerobic digestate of sludge as a potential fertilizer, focusing on the quantification of HS, the efficiency of HS recovery, and its interaction with pollutants. The potential pitfalls of current misunderstanding for HS quantification in sludge were pointed out. HS present in sludge showed potential to be used as a fertilizer, which solubilized insoluble phosphates for enhanced soil fertility.
View Article and Find Full Text PDFEnviron Sci Technol
January 2025
School of Environmental, Civil, Agricultural and Mechanical Engineering, University of Georgia, Athens 30602, Georgia, United States.
This study investigated the speciation and aqueous dissolution of macronutrients in fire ash from diverse ecosystems and speciation of ash and smoke from laboratory burning, exploring the variations and their causes. The speciation of phosphorus (P), calcium (Ca), and potassium (K) in fire ash from five globally distributed ecosystems was characterized by using X-ray absorption spectroscopy and sequential fractionation. Aqueous dissolution of the macronutrients was measured by batch experiments at acidic and alkaline pHs.
View Article and Find Full Text PDFSci Total Environ
January 2025
Institute of Chemistry and Processes for Energy, Environment and Health ICPEES UMR 7515, University of Strasbourg, F-67087 Strasbourg Cedex 3, Strasbourg, France. Electronic address:
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