ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTExtraction of Organic Pollutants from Environmental Solids with Sub- and Supercritical WaterSteven B. Hawthorne, Yu. Yang, David J. MillerCite this: Anal. Chem. 1994, 66, 18, 2912–2920Publication Date (Print):September 15, 1994Publication History Published online1 May 2002Published inissue 15 September 1994https://pubs.acs.org/doi/10.1021/ac00090a019https://doi.org/10.1021/ac00090a019research-articleACS PublicationsRequest reuse permissionsArticle...

Most organic pollutants are serious environmental concerns globally due to their resistance biological, chemical, and photolytic degradation. The vast array of uses compounds in daily life causes a massive annual release these substances into the air, water, soil. Typical examples include pesticides, polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs). Since they persistent hazardous environment, as well bio-accumulative, sensitive efficient extraction detection...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSubcritical Water Extraction of Polychlorinated Biphenyls from Soil and SedimentYu. Yang, Soren. Bowadt, Steven B. Hawthorne, David J. MillerCite this: Anal. Chem. 1995, 67, 24, 4571–4576Publication Date (Print):December 15, 1995Publication History Published online1 May 2002Published inissue 15 December 1995https://pubs.acs.org/doi/10.1021/ac00120a022https://doi.org/10.1021/ac00120a022research-articleACS PublicationsRequest reuse permissionsArticle...

The polarity of water drops dramatically when heated under enough pressure to maintain the liquid state. For example, dielectric constant (ε) is 80 at ambient temperature, but ∼30 250 °C. Thus, low tem perature can be used extract polar organics, while higher temperature will moderately and nonpolar organics. Four samples (a soil, a catalyst, two sludges) were extracted by subcritical dif ferent temperatures pressures. At lower (50−150 °C), phenols BTEX (benzene, toluene, ethylbenzene,...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCombined Temperature/Modifier Effects on Supercritical CO2 Extraction Efficiencies of Polycyclic Aromatic Hydrocarbons from Environmental SamplesYu. Yang, Ahmad. Gharaibeh, Steven B. Hawthorne, and David J. MillerCite this: Anal. Chem. 1995, 67, 3, 641–646Publication Date (Print):February 1, 1995Publication History Published online1 May 2002Published inissue 1 February...

In this study, porous layer solid-phase microextraction (SPME) was investigated for the extraction of polycyclic aromatic hydrocarbons (PAHs) from water. The coatings were prepared using silica particles (5 μm diameter) bonded with phenyl, C8, and monomeric polymeric C18 stationary phases use in HPLC. It found that several factors affected selectivity PAHs, including functional group phase, alkyl chain length phase type (monomeric or polymeric). distribution coefficients PAHs increased an...

Owing to the insolubility of binary phase system for oxidative desulfurization, a formic acid/H2O2 with quaternary ammonium salts as phase-transfer catalysts was employed in oxidation thiophene. Four catalytic systems ultrasound were carried out, tetrabutyl bromide behaved optimum active catalyst, and desulfurization rate 94.67%. Dispersion catalyst between organic aqueous phases related extraction constant. When amount exceeded 0.0019 mol L-1, would serve well transfer polar substance...

The unique characteristic of subcritical water is its widely tunable physical properties. For example, the polarity (measured by dielectric constant) significantly decreased raising temperature. At temperatures 200−250 °C (under moderate pressure to keep in liquid state), pure similar that methanol or acetonitrile at ambient conditions. Therefore, may be able serve as mobile phase for reversed-phase separations. To investigate retention behavior separation, factors BTEX (benzene, toluene,...

A simple and reliable system for determining the solubility partitioning behavior of liquid fuel components in water up to 250 °C has been developed. The shows good agreement with literature values at ambient temperature toluene fuel/water coefficients (Kfw). Toluene increased ∼23-fold by raising from 200 but was not affected changing pressure 1 50 bar. increases benzene, toluene, ethylbenzene, xylenes, naphthalene gasoline into increasing ranged 10-fold benzene 60-fold when raised °C....

There are billions of tea drinkers around the world. However, optimized tea-brewing temperature and time conditions for achieving a higher concentration antioxidants in drinks have not been thoroughly studied. Finding out brewing can benefit significantly. In this work, we studied ten from seven different popular green, Oolong, black, scented teas using hot water extraction followed by HPLC analysis. The antioxidant yield was evaluated at 25-100 °C with 5 to 720 min time. Our results show...

Subcritical water has been successfully used as an environment-friendly extraction fluid for many classes of organic compounds. While only solvent trapping was in previous subcritical extractions, sorbent tested this study. After extraction, the trap (silica-bonded C18 column) coupled to a HPLC system analysis. The coupling technique with eliminates liquid−liquid extractions and provides better sensitivity. Alkylbenzenes polycyclic aromatic hydrocarbons were extracted from sand contaminated...

The solubility of methyl, ethyl, and butyl parabens (4-hydroxybenzoate) in water was determined at (298, 373, 423, 473) K using a homemade heating/mixing system by high performance liquid chromatography analysis. increased for all three studied when temperature raised from 298 to 423 K. However, the decreased with further increase 473 This due degradation as revealed separate study. A new model developed guide estimation paraben subcritical water. values predicted this compare reasonably...

A subcritical water degradation and extraction method was developed to remediate environmental soils contaminated by highly recalcitrant organochlorine pollutants. Hydrogen peroxide used effectively decompose pollutants under conditions. As a optimization study, the static wet oxidation of chlorophenols first performed in with without added hydrogen peroxide. Complete achieved using an oxidant, thus, from sand matrix then attempted. oxidant were within 30 min at 100 °C. We investigated...

In this study, the off-line coupling of subcritical water extraction (SBWE) with chromatography (SBWC) was achieved using a sorbent trap and thermal desorption. The employed to collect extracted analytes during extraction. After extraction, connected system, desorption trapped performed before SBWC run. thermally desorbed were then introduced into separation column detected by UV detector. Anilines phenols from sand analyzed technique. Subcritical flavones orange peel followed...