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Transport of arsenic loaded by ferric humate colloid in saturated porous media
- Source :
- Chemosphere. 240
- Publication Year :
- 2019
-
Abstract
- The transport behavior of arsenic (As(V)) loaded by ferric humate (HA-Fe) colloid, denoted as HA-Fe/As(V), moving in a saturated quartz sand column, was tested in the laboratory under varying pH values, ionic strengths, and HA and Fe(III) content. The time-fractional advection-dispersion equation (fADE) model was then employed to analyze the observed migration of HA-Fe/As(V). Results showed that the stability of the HA-Fe colloid exhibited an upward trend with an increasing pH and HA content. An increasing HA content led to a decrease in the particle size of the HA-Fe colloid. However, the effect of Fe(III) concentration on colloidal particle size exhibited the opposite phenomenon. The ability of the HA-Fe colloid to load As(V) gradually increased with the increase of the Fe(III) concentration. During the co-transport of the HA-Fe/As(V) colloid, transport of As(V) was promoted with increasing pH, increasing HA and Fe(III) content, and decreasing ionic strength in the saturated porous medium. The transport behavior of As(V) can be well fitted by the fADE model. The model analysis revealed that sub-diffusion of As(V) was weakened in the HA-Fe/As(V) colloid with high HA content. Sub-diffusion of As(V) in the low pH colloid was stronger than that of the high-pH colloid, and the molecular diffusion and mechanical dispersion were more weakened in the high-pH colloid than that of the low-pH colloid. When observing varying ionic strengths, As(V) exhibited stronger sub-diffusion in the HA-Fe/As(V) colloid with a higher ionic strength. As for the Fe(III) content, transport of As(V) was mainly affected by sub-diffusion in the HA-Fe/As(V) colloid with a low Fe(III) content. These findings provided direct and necessary insights into the effects of the HA-Fe colloid on the migration of As(V) throughout saturated porous media under different hydrochemical conditions found in natural environments.
- Subjects :
- endocrine system
Environmental Engineering
Health, Toxicology and Mutagenesis
0208 environmental biotechnology
Analytical chemistry
Ionic bonding
chemistry.chemical_element
02 engineering and technology
010501 environmental sciences
Dispersion (geology)
complex mixtures
01 natural sciences
Ferric Compounds
Arsenic
Diffusion
Colloid
medicine
Water Movements
Environmental Chemistry
Colloids
Particle Size
Humic Substances
0105 earth and related environmental sciences
Molecular diffusion
Chemistry
digestive, oral, and skin physiology
Osmolar Concentration
Public Health, Environmental and Occupational Health
General Medicine
General Chemistry
Quartz
Pollution
020801 environmental engineering
Ionic strength
Ferric
Particle size
Porosity
medicine.drug
Subjects
Details
- ISSN :
- 18791298
- Volume :
- 240
- Database :
- OpenAIRE
- Journal :
- Chemosphere
- Accession number :
- edsair.doi.dedup.....35aaa2d863ad046157bd2fbf32261b4c