Oxidation of PAHs in a simplified system using peroxy-acid and glass beads: Identification of oxidizing species.

Polycyclic aromatic hydrocarbons (PAHs) are organic contaminants of concern due to their ubiquity, persistence in the natural environment and adverse health effects. Numerous studies have looked into the removal and treatment of these contaminants, with mixed results. High molecular weight PAHs have been particularly problematic due to their hydrophobicity and high affinity for organics, resulting in mass transfer limitations for even the fastest advanced oxidation processes (AOPs).

Influence of pH on sediment-associated sorption reactions of benzidine.

Benzidine has been marked as a priority chemical on the National Priorities List by the U.S. Environmental Protection Agency because of its carcinogenic nature.

Effective treatment of PAH contaminated Superfund site soil with the peroxy-acid process.

Peroxy-organic acids are formed by the chemical reaction between organic acids and hydrogen peroxide. The peroxy-acid process was applied to two Superfund site soils provided by the U.S.

Sorption and desorption behavior of benzidine in different solvent-sediment systems.

The sorption and desorption behavior of benzidine in eight solvent-sediment systems were studied using a batch method. The solvents tested included deionized water (DI), calcium chloride solution (CaCl2), sodium hydroxide solution (NaOH), acetonitrile (ACN), a mixture of acetonitrile and ammonium acetate solution (ACN-NH4OAc), methanol (MeOH), ammonium acetate solution (NH4OAc) and hydrochloric acid solution (HCl). Three sets of sorption isotherm experiments were conducted separately in these eight solvents with seven days, three weeks, and two months of contact times, respectively.

Benzidine transformation processes in natural sediments.

Aromatic amines, such as benzidine and 3,3'-dichlorobenzidine, are chemicals used in the pigment and dye processes. Release of these compounds into the environment is important because of their carcinogenic and toxic nature. In the present study, the sediment and water samples were collected from Lake Macatawa (Holland, MI, USA) and subsequently spiked with benzidine.

Short-term interactions of aniline and benzidine with three soils in both natural and artificial matrices.

The fate of aromatic amines in natural systems is important to understand due to the persistence and toxicity of these chemicals. Laboratory experiments were performed to elucidate aniline and benzidine behavior in silty-clay, sandy loam, and sandy soils, and six background matrices (rainwater, 12.5 mM CaCl(2), 25 mM CaCl(2), and each passed through soil columns).

Slow desorption behavior of one highly resistant aromatic amine in Lake Macatawa, Michigan, USA, sediment.

The desorption behavior of benzidine from Lake Macatawa (Holland, MI, USA) sediment was investigated in this study using batch solvent extraction method. Seven solvents were tested as the extracting reagents: Deionized water (DI), calcium chloride in DI (CaCl2), sodium hydroxide in DI (NaOH), acetonitrile (ACN), a mixture of acetonitrile and ammonium acetate in DI (ACN-NH4OAc), methanol (MeOH), and hydrochloric acid in DI (HCl). These solvents are proposed to react with sediment-associated benzidine by different mechanisms (e.

Sorption of benzidine and 3,3'-dichlorobenzidine to lake sediments. 1. Conceptualization and development of a multiparameter model.

Aromatic amines, such as benzidine and 3,3'-dichlorobenzidine (DCB), are part of the dyes and pigments manufacturing process. The prolonged use of these carcinogenic chemicals in the past generation has introduced a significant amount of contamination to the environment. Their persistency in several mediums has sparked a number of studies in an attempt to develop predictive tools of their fate and transport in the environment.

Concentrations and distribution of 3,3'-dichlorobenzidine and its congeners in environmental samples from Lake Macatawa.

Release of 3,3'-dichlorobenzidine (DCB), an intermediate in dye manufacturing processes, is of environmental concern due to its carcinogenic nature. An 11-year field study has been conducted to elucidate the fate and behavior of DCB and its congeners in the Lake Macatawa (Holland, MI, USA) sediment-water system. The sediments were variable in composition, ranging from sandy sediments with 1-8.

Remediation of benzo(a)pyrene in contaminated sediments using peroxy-acid.

Release of benzo(a)pyrene is of an environmental concern due to its toxic nature. To elucidate the degradation of benzo(a)pyrene in lake sediments an advanced oxidation process (AOP) employing peroxy-acids as oxidizing agents was investigated. The sediments used in this study were collected from Lake Macatawa (Holland, MI) throughout the eastern basin and ranged in composition from sandy to silty-clay.

Optimization of the peroxy acid treatment of alpha-methylnaphthalene and benzo[a]pyrene in sandy and silty-clay sediments.

The majority of polycyclic aromatic hydrocarbons (PAHs) released to the environment come from anthropogenic sources involving the incomplete combustion of organic compounds. Several techniques are available for the degradation of PAHs. Among the abiotic/biotic processes used to degrade PAHs, an alternative strategy utilizing a primary chemical oxidative step to be combined with a biological was created.

Liquid chromatographic aqueous product characterization of high-energy electron beam irradiated 2-chlorobiphenyl solutions.

Polychlorinated biphenyls (PCBs) are of environmental concern due to their toxic nature. Ionizing radiation has been suggested as a means to remediate PCB-contaminated samples in complex matrices. A set of experiments was performed to qualitatively and quantitatively determine the aromatic degradation products of 2-monochlorobiphenyl (2-MCB) in an aqueous system exposed to ionizing radiation.

Remediation of alpha-methylnaphthalene-contaminated sediments using peroxy acid.

Laboratory experiments have been conducted to elucidate the degradation of alpha-methylnaphthalene in lake sediments using an advanced oxidation process (AOP) employing peroxy-acids as oxidizing agents. Abiotic degradation of alpha-methylnaphthalene was observed in sediment samples exposed to a 1:1:1 v/v/v mixture of water/organic acid/hydrogen peroxide solution. Sediment samples were collected from Lake Macatawa (Holland, MI) and ranged in total organic carbon content from 2.

Transport behavior of 3,3'-dichlorobenzidine in a freshwater estuary.

Like many hydrophobic organic compounds, 3,3'-dichlorobenzidine (DCB) partitions preferentially to (sediment) particles in lake systems. As such, the behavior of DCB in these systems is substantially affected by the movement of sediments. A field investigation of DCB distribution in sediments of Lake Macatawa (Holland, MI, USA) was initiated.

Hydrogen atom abstraction reactions of charged polyaromatic sigma-radicals related to the active intermediates of the enediyne antitumor drugs.

Polar effects are demonstrated to play an important role in controlling the reactivity of polyaromatic sigma-radicals that are structurally related to the active intermediates of the enediyne anticancer type antibiotics. This was accomplished by measuring the rate constants of hydrogen atom abstraction for novel, charged dehydroquinolines, dehydroisoquinolines, dehydrobenzenes, and dehydronaphthalenes in the gas phase by using Fourier-transform ion cyclotron resonance mass spectrometry. The reactivity trends observed for these radicals upon hydrogen atom abstraction from tetrahydrofuran and 2-methyltetrahydrofuran, simple models of deoxyribose, do not reflect differences in reaction exothermicities, radical sizes, exact location of the radical site in the ring system, or heteroatom-radical site distances.

Photodechlorination of 3,3'-dichlorobenzidine in water.

Laboratory experiments have been conducted to elucidate the photochemical behavior of 3,3'-dichlorobenzidine (DCB) and its congeners in aquatic systems. Photodechlorination of DCB was observed in aqueous samples that were irradiated with monochromatic radiation from a variable-wavelength laser at several wavelengths in the range 300 nm < or = lambda < or = 360 nm. Analytical measurements performed by high-performance liquid chromatography (HPLC) and Fourier-transform ion cyclotron resonance (FT-ICR) mass spectrometry revealed that 3-chlorobenzidine (MCB) was produced as a transient intermediate in the photodechlorination process, with subsequent photodechlorination to yield benzidine as a stable photoproduct.