Enhanced humification by carbonated basic oxygen furnace steel slag – II. Process characterization and the role of inorganic components in the formation of humic-like substances

Influence of the composition of the initial mixtures on the chemical composition, physicochemical properties and humic-like substances content of composts

“…The specific composting conditions that optimize the transformation of organic raw materials into HS-like are still not fully understood (Barje et al, 2012;Qi et al, 2012). This study aimed at assessing the effect of the proportion of bulking agent, C-and N-rich raw materials and C/N ratio on the final properties of composts.…”

“…Recently our team showed that humiclike substances (HS-like), which can be further used as liquid organic amendments, could be recovered from low quality composts (Silva et al, 2013). Although there are several ongoing studies on the optimization of the operational composting conditions, the information regarding the influence of these conditions on the content and characteristics of HS-like is scarce (Barje et al, 2012;Qi et al, 2012). The knowledge of key factors that influence humification would allow the improvement of the composts quality in terms of HS-like content.…”

Binding Characteristics and Dissociation Kinetics for Iron(II) Complexes with Seawater Extractable Organic Matter and Humic Substances in a Compost

“…5 Such Fe(III)-oxides can be reduced to soluble species in the presence of DOM, such as humic substances. 6 DOM is capable of reducing Fe(III), and all of the reduced Fe(II) becomes complexed with DOM.…”

Determination of Labile Fe(II) Species Complexed with Seawater Extractable Organic Matter Under Seawater Conditions Based on the Kinetics of Ligand-exchange Reactions with Ferrozine

“…16 In this technique, seawater extractable organic matter (SWEOM) from the compost serves as a chelator of Fe and allows for its elution from the steel slag. 17,18 Fe(III)-oxides are found on the surface of the steel slag, 19 and can be reduced to soluble Fe(II) species in the presence of dissolved organic matter. 20 It has been reported that all of the reduced Fe(II) species are complexed with dissolved organic matter.…”

“…2,3,22,24,25 Readily dissociable complexes (labile species) are the likely primary source of soluble iron for algae. 2,19,[26][27][28] A key factor in the uptake of Fe(II) involves ligand-exchange reactions between dissolved organic matter and receptor proteins on the cell-membrane. 2 The kinetics of ligand-exchange reactions of Fe(II)-humic acid complexes have been investigated using ortho-phenanthroline or ferrozine (FZ) as models of receptor proteins, 17,29 although the conditions (pH 3.6 or 5, I = 0.02) were far from those for seawater (pH 8, I = 0.7).…”