ChemInform Abstract: Batch Dissolution Kinetics: The Shrinking Sphere Model with Salts and Its Potential Application to Biogenic Silica

ChemInform ◽  
2008 ◽  
Vol 39 (39) ◽  
Author(s):  
Victor W. Truesdale
Keyword(s):  
Potential Application ◽  
Biogenic Silica ◽  
Dissolution Kinetics ◽  
Sphere Model ◽  
Batch Dissolution

In vitro, batch-dissolution of biogenic silica in seawater – the application of recent modelling to real data

2005 ◽  
Vol 66 (1) ◽  
pp. 1-24 ◽  
Author(s):  
Victor W. Truesdale ◽  
Jim E. Greenwood ◽  
Andrew R. Rendell
Keyword(s):  
Biogenic Silica ◽  
Real Data ◽  
Batch Dissolution

Dissolution kinetics of biogenic silica from the water column to the sediments

2002 ◽  
Vol 66 (3) ◽  
pp. 439-455 ◽  
Author(s):  
Dirk Rickert ◽  
Michael Schlüter ◽  
Klaus Wallmann
Keyword(s):  
Water Column ◽  
Biogenic Silica ◽  
Dissolution Kinetics ◽  
Kinetics Of

scholarly journals Association of trace elements and dissolution rates of soil iron oxides

Soil Research ◽  
2014 ◽  
Vol 52 (1) ◽  
pp. 1 ◽  
Author(s):  
D. Ketrot ◽  
A. Suddhiprakarn ◽  
I. Kheoruenromne ◽  
B. Singh
Keyword(s):  
Trace Elements ◽  
Dissolution Rate ◽  
Significant Proportion ◽  
Dissolution Kinetics ◽  
Major And Trace Elements ◽  
Cube Root ◽  
Fe Oxide ◽  
Fe Oxides ◽  
Batch Dissolution ◽  
Dissolution Behaviour

In this study, nine Oxisols and five Ultisols from Thailand were used to determine the association of major and trace elements with iron (Fe) oxides. The Fe oxides were concentrated and the association of elements (Al, Ca, Cu, Cr, Mg, Mn, Ni, Pb, P, Si, V, Ti, Zn) with Fe was evaluated using batch dissolution in 1 m HCl at 20°C. The dissolution behaviour of Fe oxide concentrates was determined using batch dissolution and flow-through reactors. In addition to Fe, both Al and Ti were present in significant amounts in the Fe oxide concentrates. Manganese was the most abundant trace element, and Cu, Zn, Pb and As concentrations were <250 mg kg–1 in most samples. The dissolution behaviour of Fe-oxide concentrates indicated that Al, Cr and V were mostly substituted for Fe3+ in the structure of goethite and hematite. A significant proportion of Mn, Ni, Co, Pb and Si was also present within the structure of these minerals. Some Mg, Cu, Zn, Ti and Ca was also associated with Fe oxides. The dissolution kinetics of Fe oxide concentrates was well described by three models, i.e. the cube root law, Avrami–Erofejev equation and Kabai equation, with the dissolution rate constants (103k) corresponding to the three models ranging from 0.44 to 6.11 h–1, from 1.01 to 4.40 h–1 and from 0.03 to 4.12 h–1, respectively. The k constants of Fe oxide concentrates in this study were significantly and negatively correlated with the mean crystal dimension derived from [110] and [104] of hematite, the dominant mineral in most samples. The steady-state dissolution rate of a soil Fe-oxide concentrate (sample Kk) was substantially higher than for synthetic goethite under highly acidic conditions; this is possibly due to the greater specific surface area of sample Kk than the synthetic goethite.

Dissolution kinetics of biogenic silica collected from the water column and sediments of three Southern California borderland basins

2009 ◽  
Vol 113 (1-2) ◽  
pp. 41-49 ◽  
Author(s):  
Tao Cheng ◽  
Douglas E. Hammond ◽  
William M. Berelson ◽  
Janet G. Hering ◽  
Suvasis Dixit
Keyword(s):  
Water Column ◽  
Biogenic Silica ◽  
Southern California ◽  
Dissolution Kinetics ◽  
California Borderland ◽  
Kinetics Of

scholarly journals Lead Immobilization and Hydroxamate Ligand Promoted Chloropyromorphite Dissolution

2014 ◽  
Vol 2014 ◽  
pp. 1-10
Author(s):  
Nadia K. Adam
Keyword(s):  
Dissolution Kinetics ◽  
Dissolution Behavior ◽  
Acetohydroxamic Acid ◽  
Model Calculations ◽  
Batch Dissolution ◽  
Phosphate Mineral ◽  
Soils And Sediments ◽  
Lead Release ◽  
Ph Dependent ◽  
Aqueous Complexation

The immobilization of lead, a major environmental contaminant, through phosphate amendments to form the sparingly soluble lead phosphate mineral chloropyromorphite [Pb5(PO4)3] (CPY) is an effective in situ strategy for soil remediation. An important question is the effect of microbial processes on this remediation. Here, we investigate the role of the microbial siderophore ligand desferrioxamine-D1 (DFO-D1) and its analog acetohydroxamic acid (aHA) in CPY lability using pH-dependent batch dissolution kinetics and model calculations. Both (0.01) M aHA and (0.00024) M DFO-D1 are similarly effective and enhance lead release from CPY by more than two orders of magnitude at pH > 6 compared to in the absence of ligands. This is consistent with model calculations of pH-dependent (aqueous) complexation of lead with hydroxamate ligands. More importantly, pH-dependent ligand sorption is predictive of its ligand promoted dissolution behavior. Our results suggest that organic ligands can significantly increase CPY lability at alkaline pHs in soils and sediments and that addition of P amendments to immobilize Pb as CPY may only be successful at acid pHs.

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