Related Experiment Video
Updated: Jan 3, 2026
08:34
A Dual-Functional Electroactive Filter Towards Simultaneously SbIII Oxidation and Sequestration
Published on: December 5, 2019
5.9K
Thallium(I) sequestration by jarosite and birnessite: Structural incorporation vs surface adsorption
J Aguilar-Carrillo1, L Herrera-García2, Iván A Reyes-Domínguez3
1CONACyT, Department of Environmental Technology, Institute of Metallurgy, UASLP, 78210, San Luis Potosí, Mexico.
Environmental Pollution (Barking, Essex : 1987)
|November 21, 2019
Summary
Jarosite and birnessite minerals effectively sequester toxic thallium (Tl) through distinct mechanisms. Jarosite incorporates Tl into its structure, while birnessite adsorbs Tl irreversibly, impacting Tl environmental mobility.
Area of Science:
- Environmental geochemistry
- Mineralogy
- Environmental science
Background:
- Jarosite and birnessite are key secondary minerals influencing trace element mobility.
- Geochemical interactions of these minerals with toxic thallium (Tl) are poorly understood.
- Understanding Tl sorption is crucial for assessing environmental risks, especially in mining-impacted areas.
Purpose of the Study:
- To investigate the sorption behavior of Tl(I) onto synthetic jarosite and birnessite.
- To elucidate the mechanisms of Tl sequestration by these minerals under acidic conditions.
- To assess the role of jarosite and birnessite in the environmental fate of thallium.
Main Methods:
- Sorption and desorption experiments were conducted using synthetic jarosite and birnessite.
- Experiments mimicked natural acidic conditions and varied Tl(I) concentrations.
- Mineral characterization involved X-ray diffraction (XRD), FTIR, SEM, and ICP analyses.
Main Results:
- Both jarosite and birnessite effectively removed aqueous Tl(I) via different mechanisms.
- Jarosite incorporated Tl(I) into its structure, forming Tl(I)-jarosite and dorallcharite.
- Birnessite adsorbed Tl(I) irreversibly, showing a strong affinity for Tl across studied concentrations.
- High Tl/Mn ratios inhibited birnessite formation, leading to Tl(III) oxidation and avicennite precipitation.
Conclusions:
- Jarosite and birnessite play significant roles in controlling thallium mobility and fate in the environment.
- Distinct sorption mechanisms (incorporation vs. adsorption) highlight mineral-specific interactions with Tl(I).
- Environmental conditions, such as Tl/Mn ratios, can alter mineral behavior and Tl speciation.
Related Concept Videos
01:19Complexation Equilibria: The Chelate Effect
1.1K
In complexation reactions, metal atoms or cations interact with ligands to form donor-acceptor adducts called metal complexes. Ligands that bind through one donor site are monodentate, ligands with two donor sites are bidentate, and those with more than two donor sites are polydentate ligands. For example, ethylene diamine is a bidentate ligand that binds through two nitrogen donor atoms, forming a five-membered ring. EDTA is a polydentate ligand that binds through four oxygen and two nitrogen...
1.1K
01:09Colloidal precipitates
4.6K
The high insolubility of some precipitates can result in an unfavorable relative supersaturation. This can lead to colloidal particles with a large surface-to-mass ratio, where adsorption is promoted. For instance, in the precipitation of silver chloride, silver ions are adsorbed on the surface of the colloidal particles, forming a primary layer. This layer attracts ions of opposite charge (such as nitrate ions), forming a diffuse secondary layer of adsorbed ions. This electric double layer...
4.6K
00:56Extraction: Advanced Methods
1.0K
Metal ions can be separated from one another by complexation with organic ligands–the chelating agent– to form uncharged chelates. Here, the chelating agent must contain hydrophobic groups and behave as a weak acid, losing a proton to bind with the metal. Since most organic ligands used in this process are insoluble or undergo oxidation in the aqueous phase, the chelating agent is initially added to the organic phase and extracted into the aqueous phase. The metal-ligand complex is...
1.0K
02:42Valence Bond Theory
10.9K
Coordination compounds and complexes exhibit different colors, geometries, and magnetic behavior, depending on the metal atom/ion and ligands from which they are composed. In an attempt to explain the bonding and structure of coordination complexes, Linus Pauling proposed the valence bond theory, or VBT, using the concepts of hybridization and the overlapping of the atomic orbitals. According to VBT, the central metal atom or ion (Lewis acid) hybridizes to provide empty orbitals of suitable...
10.9K
00:43Complexometric Titration: Ligands
2.1K
Different monodentate and polydentate ligands are used as complexing agents in complexometric titration reactions. The formation of complexes by mono- and bidentate ligands involves two or more intermediate steps, limiting their use as complexing agents. In comparison, polydentate ligands can form complexes with metal ions in a single-step process, facilitating sharper end points. This means polydentate ligands, such as amino carboxylic acid derivatives, are most commonly employed in...
2.1K
01:21Drug Distribution: Tissue Binding
3.8K
Upon entering the systemic circulation, drugs can distribute into the interstitial and intracellular fluid of various tissue cells. This distribution is facilitated by the binding of drugs to different cellular components within tissues, which may lead to drug accumulation in specific areas. Drugs bound to tissue components serve as reservoirs that release free drugs back into the system, prolonging the drug's overall action. However, this accumulation can also result in local toxicity.
For...
For...
3.8K