A study on the dissolution kinetics of basalt-water interaction under different pH conditions I: Release of elements and pH neutralization effect

1993 ◽  
Vol 12 (2) ◽  
pp. 183-191
Author(s):  
Dang Zhi ◽  
Hou Ying
Keyword(s):  
Dissolution Kinetics ◽  
Water Interaction ◽  
Ph Conditions ◽  
Ph Neutralization ◽  
Kinetics Of

The dissolution of calcite at pH > 7: kinetics and mechanism

1990 ◽  
Vol 330 (1609) ◽  
pp. 47-70 ◽  
Keyword(s):  
Calcium Carbonate ◽  
Solubility Product ◽  
Dissolution Kinetics ◽  
Theoretical Modelling ◽  
Normal Rate ◽  
Bulk Solution ◽  
Rate Law ◽  
Rate Laws ◽  
Ph Conditions ◽  
Kinetics Of

A technique is described that allows an assessment of the various candidate rate laws that have been proposed to predict the dissolution kinetics of calcite under high pH conditions. A combination of theoretical modelling and experimentation allows us to choose the following rate law as that which best fits the observed data: rate ( mol c m − 2 s − 1 ) = k − k ′ [ C a 2 + ] s [ CO 3 2 − ] s ′ , where k ′ = k / K sp and K sp is the solubility product of calcium carbonate. The modelling developed differs from previous studies in that it deals in terms of surface concentrations of reactants, [ Ca 2 + ] s and [ CO 3 2 − ] , as opposed to those present in bulk solution.

scholarly journals Gelatin Beads/Hemp Hurd as pH Sensitive Devices for Delivery of Eugenol as Green Pesticide

2021 ◽  
Author(s):  
Gianluca Viscusi ◽  
Giuliana Gorrasi
Keyword(s):  
Release Kinetics ◽  
Barrier Properties ◽  
Ph Sensitive ◽  
Release Behavior ◽  
Sorption Coefficient ◽  
Highly Sensitive ◽  
Mean Diameter ◽  
Ph Conditions ◽  
Kinetics Of ◽  
Hemp Hurd

AbstractIn this paper gelatin beads reinforced with natural hemp hurd have been produced as pH sensitive devices for the release of eugenol, as green pesticide. The composites beads, with a mean diameter of about 1 mm, were obtained by polymer droplet gelation in sunflower oil. Thermal properties were evaluated showing no noticeable difference after the introduction of hemp hurd. Barrier properties demonstrated an improvement of hydrophobization. The introduction of 5% w/w of hemp hurd led to a reduction of sorption coefficient of about 85% compared to unloaded gelatin beads. Besides, the diffusion coefficient decreased, introducing 5% w/w of hemp hurd, from 8.91 × 10−7 to 0.77 × 10−7 cm2/s. Swelling and dissolution phenomena of gelatin beads were studied as function of pH. The swelling of gelatin beads raised as pH increased up to 2.3 g/g, 9.1 g/g and 27.33 g/g at pH 3, 7 and 12, respectively. The dissolution rate changed from 0.034 at pH 3 to 0.077 h−1 at pH 12. Release kinetics of eugenol at different pH conditions were studied. The released eugenol after 24 h is 98%, 91%, 81 and 63% w/w (pH 3), 87%, 62%, 37 and 32 wt% (pH 7) and 81%, 68%, 60 and 52 wt% (pH 12) for unloaded gelatin beads and gelatin beads with 1%, 3 and 5% of hemp hurd, respectively. The eugenol release behavior was demonstrated to be highly sensitive to the pH release medium, which allows to tune such devices as green pesticide release systems in soils with different level of acidity/basicity.

Short time dissolution kinetics of refractory elements Fe, Al, and Ti in Asian outflow-impacted marine aerosols and implications

2013 ◽  
Vol 79 ◽  
pp. 93-100 ◽  
Author(s):  
Shih-Chieh Hsu ◽  
Fei-Jan Lin ◽  
Tsun-Hsien Liu ◽  
Shuen-Hsin Lin ◽  
Shuh-Ji Kao ◽  
...  
Keyword(s):  
Dissolution Kinetics ◽  
Marine Aerosols ◽  
Refractory Elements ◽  
Short Time ◽  
Kinetics Of
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