Search

Abstract: Fogwater and air samples were collected in Baton Rouge between November 2004–February 2005 and during February 2006 at Houston. Organic compounds present in the fog samples were detected, quantified and then grouped into different compound classes based on molecular size, solubility and polarity using gas chromatography/mass spectrometry, high performance liquid chromatography with diode array detection and ion chromatography. Organic compounds were grouped as n-alkanes, aromatics and polycyclic aromatics, carbonyls, alcohols, amides and esters. Organic compounds in fog and air samples in Houston indicated clear urban/industrial anthropogenic origin, while compounds detected in Baton Rouge fog and air samples showed a mix of both agricultural and urban/industrial anthropogenic inputs. Among the various polycyclic aromatic compounds detected, the total concentration of naphthalene and its derivatives was 2.8 μg m−3 in Houston and 0.08 μg m−3 in Baton Rouge air. Analysis of concentrations of organic compounds pre- and post- fog revealed that compounds with low vapor pressure had higher scavenging efficiency in fog sampled at the two locations. Concentrations of organic compounds in fog samples were higher than those predicted by conventional air-water Henry''s law equilibrium. Observed higher concentrations in the aqueous phase were modeled accounting for surface adsorption and accumulation of gas phase species and the presence of humic-like substances in fogwater. [Copyright &y& Elsevier]

The interest in the use of non-noble metal catalysis is quite relevant to biomass processing due to costs, environmental concerns and the substantial scale of these operations. The aim of this article is to cover all aspects of the use of iron based catalysts in various biomass processing applications, especially focusing on the developments in the last five years. The appeal of metallic iron and its compounds in catalysis as well as the diversity of the type of transformations are discussed in the introduction sections of this review. The recent advances in the use of iron or its compounds in biomass pretreatment, saccharification, liquefaction and pyrolysis are reviewed as major topics in the review article. In addition, the use iron based catalysts in processing biomass derived small molecules to fuel; polymer and chemical feedstocks are also discussed in the article. • Iron catalysts are attractive due to high abundance and relatively low toxicity. • Uses in pretreatment, saccharification, liquefaction and pyrolysis are reviewed. • Transformations of biobased molecules to fuels and feedstocks are also reviewed. [ABSTRACT FROM AUTHOR]

Fog samples were collected in two population centers of the US Gulf Coast (Houston, Texas and Baton Rouge, Louisiana) using Caltech active strand cloud collectors. A total of 32 fogwater samples were collected in Baton Rouge (November 2004–February 2005) and Houston (February 2006). These samples were analyzed for pH, total and dissolved organic carbon, major inorganic ions, and a variety of organic compounds including organic acids, aromatics, carbonyls, and linear alkanes. Fogs in both environments were of moderate density, with typical fog liquid water contents <100mgm−3. Fog samples collected in Houston reflect a clear influence of marine and anthropogenic inputs, while Baton Rouge samples also reflect agricultural inputs. The volume-weighted mean fog pH was somewhat more acidic (∼4.3) in Houston than in Baton Rouge (∼5.0). A wide pH range was observed in fog at both locations. Houston fog had higher concentrations of Cl−, NO3 −, Na+, Mg2+, and Ca2+. Sulfate to nitrate ratios were high in fogs at both locations, typical of many clouds in the eastern US. Total organic carbon concentrations were much higher in Houston fogs than in Baton Rouge fogs. Efforts to speciate dissolved organic carbon (DOC) reveal large contributions from organic acids and carbonyls, with smaller contributions from other organic compound families including aromatics, alkanes, amides, and alcohols. Approximately 40% of the fog DOC was unspeciated in samples from both study locations. [Copyright &y& Elsevier]