Chelation extraction of lead from soil using pyridine-2,6-dicarboxylic acid

Use of a chelating agent to determine the metal availability for leaching from soils and wastes

“…One possible explanation for the increased release using EDTA is that the dilute chelant solution was aggressive enough to dissolve a large fraction of the solid phase mineral. However, dilute solutions of EDTA and other chelating agents have been found to be much less aggressive towards solid phase mineralization than strong acids or caustics [19,24,25]. For example, the dissolution of well-crystallized Fe(II) oxide phases (goethite or hematite), with concentrations of EDTA similar to that used in this study, has been found to be kinetically controlled, requiring up to 3 months of contact time [24] Shorter contact times lead to the negligible dissolution of well-crystallized Fe(II) oxides.…”

“…However, dilute solutions of EDTA and other chelating agents have been found to be much less aggressive towards solid phase mineralization than strong acids or caustics [19,24,25]. For example, the dissolution of well-crystallized Fe(II) oxide phases (goethite or hematite), with concentrations of EDTA similar to that used in this study, has been found to be kinetically controlled, requiring up to 3 months of contact time [24] Shorter contact times lead to the negligible dissolution of well-crystallized Fe(II) oxides. In contrast, greater than 80% of amorphous Fe(III) oxides may be dissolved in solutions of 50 mM EDTA, 0.5M acetic acid and1M HNO 3 in``overnight'' extractions [25].…”

Use of a Chelating Agent to Determine the Metal Availability for Leaching From Soils and Wastes

“…In order to optimize the EDTA procedure, eighteen test conditions were tested representing a full factorial design of three EDTA concentrations (50, 100, and 150 mM), two LS ratios (50 and 100 ml/g dry) and three contact times (18,24, and 48 h). For each of two replicates, a mass of MSWI combined ash equivalent to 4 g dry was put into each of 18 500-ml HDPE extraction vessels.…”

Pre-treatment of the paper pulp in the bleaching process using biodegradable chelating agents

“…1), is a constituent of bacterial spores. PDA revealed to be a ready-biodegradable compound according to the OECD guidelines (Martins et al 2014), and due to its ability to complex with metal ions, it has been studied for remediation of soils (Macauley and Hong 1995;Hong and Chen 1996), used in detergents and cleaning applications (Rattinger et al 1994;Boskamp 1990). It is mentioned as a component of a bleaching composition by Turner et al (1997), but the study was focused on the textile bleaching and was used in a hydrogen peroxide composition together with other compounds.…”