EDT in Environmental Remediation

Review Article

1,2-Ethanedithiol application review · CAS 540-63-6

Last updated: October 2026

Abstract

The strong affinity of soft sulfur donors for soft metal ions underpins the use of 1,2-ethanedithiol in water treatment. This article reviews thiol-functionalized metal-organic frameworks, the adsorption of thallium and silver, the soft–soft interaction principle that governs selectivity, and emerging applications in environmental science.

6.1Thiol-Functionalized MOFs

Metal-organic frameworks offer a high internal surface area that can be decorated with thiol groups. Grafting EDT, or using it to post-synthetically modify a framework, produces adsorbents whose sulfur sites capture heavy metals from aqueous solution (Hoyle & Bowman, 2010).

Framework–CH=CH₂ + HSCH₂CH₂SH → Framework–S–CH₂CH₂SH

Reaction 1. Radical thiol-ene grafting of EDT onto a vinyl-functionalised framework.Conditions: Photoinitiator with UV light at ambient temperature, inert atmosphere.

6.2Heavy Metal Adsorption (Tl, Ag)

Thallium and silver ions bind strongly to the sulfur donors of functionalized frameworks, and the resulting uptake can exceed that of unmodified materials. The adsorbed metals are later recovered by elution, allowing the adsorbent to be regenerated for repeated cycles.

Table 1. Reported uptake of selected soft metal ions by thiol-functionalized adsorbents.

Metal ion	Adsorbent type	Binding motif	Uptake trend
Tl(I)	Thiol-functionalized MOF	S–Tl coordination	High
Ag(I)	Thiol-functionalized MOF	S–Ag coordination	High
Cd(II)	Unmodified framework	O-donor	Low
Pb(II)	Thiol-functionalized framework	Mixed S/O	Moderate

Qualitative summary based on the hard–soft acid–base behaviour of thiol sulfur donors (Pearson, 1963).

6.3Soft–Soft Interaction Principle

According to hard–soft acid–base theory, soft sulfur donors prefer soft acceptors. EDT therefore discriminates in favour of mercury, silver, thallium and gold over harder ions such as calcium or magnesium, giving the adsorbent a useful selectivity in complex water matrices (Pearson, 1963).

6.4Emerging Applications

Current research extends thiol-functionalized materials toward membrane filters, sensor coatings and sorbents for remediation of contaminated groundwater. The combination of high affinity and regenerability keeps dithiol chemistry central to these developments.

References

Hoyle, C. E., & Bowman, C. N. (2010). Thiol-ene click chemistry. Angewandte Chemie International Edition, 49(9), 1540–1573.
Pearson, R. G. (1963). Hard and soft acids and bases. Journal of the American Chemical Society, 85(22), 3533–3539.

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