Influence of Temperature and Surfactants on the Solubilization of Hexachlorobutadiene and Hexachloroethane

Abstract

The solubilization of hexachlorobutadiene (HCBD) and hexachloroethane (HCA) in water as a function of temperature and in the presence of surfactants was investigated in order to predict their fate in groundwater and to increase their recovery. HCBD and HCA solubility data were experimentally determined at five temperatures in the range from (285.15 to 318.15) K. Thermodynamic parameters for dissolution (Δ sol G°, Δ sol H°, and Δ sol S°) have been calculated in order to propose a physical explanation of the minimum solubility observed between 293.15 and 298.15 K for both compounds. The solubilization process appeared to be influenced by the network of water molecules rather than by physical and chemical properties of HCBD or HCA, due to an opposite effect of temperature onto Brownian motion, which increases with temperature, and hydrogen-bond network, which collapses with temperature. Concerning the influence of surfactants, determination of the micelle−water partition coefficients (K mw) and the molar solubilization ratio (MSR) has shown that the solubilization per micelle was more important for nonionic surfactants Triton X-100 and Tween 80 than for anionic SDBS. Also, the increase of solubility was 1 order of magnitude higher for liquid HCBD than for crystalline HCA irrespective of surfactant.

In Situ Chemical Reduction of Chlorinated Organic Compounds

“…Temperature is known to have an effect on many physical and chemical properties of COCs, such as their solubility, Henry's law constant, density, viscosity, or interfacial tension (Stephenson 1992;Sleep and Ma 1997;Heron et al 1998;Knauss et al 2000;Mackay et al 2006;Chen et al 2012;Rodrigues et al 2017b;Koproch et al 2018), thus affecting their transport and fate processes. Temperature has also an effect on chemical reactions.…”

Elucidating the dechlorination mechanism of hexachloroethane by Pd-doped zerovalent iron microparticles in dissolved lactic acid polymers using chromatography and indirect monitoring of iron corrosion

“…The objective of our study was to elucidate the degradation mechanism of hexachloroethane (HCA, C 2 Cl 6 ) using Pd-mZVI in PLA, through the indirect monitoring of iron corrosion and its associated changes in solution chemistry by means of continuous measurements of pH, ORP and conductivity. HCA is a common highly chlorinated pollutant found in soil and groundwater, with a low aqueous solubility (Rodrigues et al 2017b). It is mainly used in the production of pyrotechnic devices and metal alloys, but it can also be a by-product of fabricating lower chlorination products (Stringer and Johnston 2001).…”