Author: Zhongbao LiuPublisher:
ISBN:
Category :
Languages : en
Pages : 0
Book Description
Surfactant Solubilization and Biodegradation of Polycyclic Aromatic Hydrocarbon Compounds in Soil/aqueous and Aqueous Systems
Author: Zhongbao LiuSolubilization and biodegradation of polycyclic aromatic hydrocarbon compounds in soil-water suspensions with surfactants
Author: Shonali LahaSurfactant Effects on Solubilization, Dissolution and Biodegradation of Polycyclic Aromatic Hydrocarbons from Non-aqueous Phase Liquids
Author: Leticia Alonso BernardezPublisher:
ISBN:
Category :
Languages : en
Pages : 410
Book Description
"The objective of the thesis was to investigate the effects of nonionic surfactants on the dissolution and biodegradation of polycyclic aromatics hydrocarbons (PAHs) from a multicomponent non-aqueous phase liquids (NAPLs)." --
Solubilization and Biodegradation of Hydrophobic Organic Compounds in Soil
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 5
Book Description
Nonionic surfactants may strongly interact with hydrophobic organic compounds (HOCs), soil, and microorganisms in soil/aqueous systems. These interactions affect the potential for surfactant-facilitated HOC transport in soil and groundwater systems, and the feasibility of engineered surfactant cleanup of contaminated sites (McCarthy and Wober, 1991). At sufficiently high bulk liquid concentrations at 25 C, most nonionic surfactants form regular micelles in single-phase solutions, whereas certain surfactants, such as C12E4, may form bilayer lamellae or other types of aggregates in more complex two-phase solutions. The critical concentrations for the onset of micelle and aggregate formation are termed the critical micelle concentration (CMC) and the critical aggregation concentration (CAC), respectively. Important changes occur in surfactant sorption, surfactant solubilization of HOCs, and microbial mineralization of HOCs in the presence of nonionic surfactants at or near these critical surfactant concentrations.
The Potential for Solubilizing Agents to Enhance the Remediation of Hydrophobic Organic Solutes in Soil-water Suspensions
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 16
Book Description
This paper discusses the feasibility for use of surfactant solubilizing agents to enhance the solubility and the rate of microbial degradation of hydrophobic organic solutes in soil-water suspensions. Hydrophobic organic contaminants are strongly sorbed to soil or sediment material, and as a consequence the rate of microbial degradation may depend greatly on the desorption of the sorbed-phase contaminant and the accessibility of the contaminant to soil microorganisms. Chemical solubilizing agents may enhance the rate of hydrophobic organic solute degradation by increasing the rate of solute desorption from soil and the extent of solute partitioning to the aqueous phase. The presentation will review on-going research on: surfactant solubilization of polycyclic aromatic hydrocarbon (PAH) compounds in clean water, and in soil-water suspensions; and experiments to assess if the addition of surfactant to soil-water suspension results in faster rate of mineralization of PAH compounds in soil.
Surfactant-Enhanced In Situ Biodegradation of Strongly Sorbing Organic Substances in Soil Environments
Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 62
Book Description
Low-solubility Polycyclic Aromatic Hydrocarbons such as phenanthrene are easily biodegradable but due to sorption onto soil or/or their presence in a non-aqueous phase, their bioavailability is greatly reduced. In an aqueous environment where surfactants exist above their critical micelle concentration hydrophobic contaminant will partitioning into the hydrophobic core of the micelle. This enhances the apparent solubility of these hydrocarbons and therefore also their desorption from soils. Conceivably, in the absence of any inhibitory effects, such surfactants may enhance the biodegradation of the hydrocarbon. Through a set of screening experiments a group of non-ionic surfactants were identified which do not inhibit the bacterial degradation of the phenanthrene. A mathematical model was formulated to describe the interaction of the biomass-contaminant-water-surfactant system. The model assumes that the surfactant affects the solubility of phenanthrene and does not affect the biochemical characteristics of the biomass. An effective bioavailable concentration was defined. The model predicts experimental data well indicating that a part of the phenanthrene in the micelle phase can be degraded simultaneously with the phenanthrene in the aqueous phase. (jg) p.2.
The Potential for Solubilizing Agents to Enhance the Remediation of Hydrophobic Organic Solutes in Soil-water Suspensions. [Quarterly Report].
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Author: Publisher:
ISBN:
Category :
Languages : en
Pages : 16
Book Description
This paper discusses the feasibility for use of surfactant solubilizing agents to enhance the solubility and the rate of microbial degradation of hydrophobic organic solutes in soil-water suspensions. Hydrophobic organic contaminants are strongly sorbed to soil or sediment material, and as a consequence the rate of microbial degradation may depend greatly on the desorption of the sorbed-phase contaminant and the accessibility of the contaminant to soil microorganisms. Chemical solubilizing agents may enhance the rate of hydrophobic organic solute degradation by increasing the rate of solute desorption from soil and the extent of solute partitioning to the aqueous phase. The presentation will review on-going research on: surfactant solubilization of polycyclic aromatic hydrocarbon (PAH) compounds in clean water, and in soil-water suspensions; and experiments to assess if the addition of surfactant to soil-water suspension results in faster rate of mineralization of PAH compounds in soil.
Biosurfactant Enhanced Bioremediation of Polycyclic Aromatic Hydrocarbon Contaminated Environmental Media
Author: Bezza Fisseha AndualemPublisher:
ISBN:
Category : Bioremediation
Languages : en
Pages : 268
Book Description
Polycyclic aromatic hydrocarbons (PAHs) are a diverse class of toxicants that are ubiquitously and persistently present in the environment. These compounds present a risk for human health and the environment, as they are mutagens, carcinogens and teratogens. Bioremediation has shown promise as a potentially effective and low-cost treatment option, but concerns about the slow process rate and bioavailability limitations have hampered more widespread use of this technology. In the fundamental work of this thesis a series of experiments was designed utilizing the biosurfactant produced by Pseudomonas aeruginosa LBP5, LBP9 and CB1. Specifically, these experiments were designed to determine if the presence of various levels of partially purified biosurfactants produced by the isolates, would affect the degradation of a range of PAHs. The biodegradation and biotransformation of PAHs were studied in three bioremedial systems: soil slurry, liquid culture experiments with enriched consortium on PAHs from petroleum contaminated sites and Bioslurry reactor study with autochthonous consortium. Biosurfactant-producing and polycyclic aromatic hydrocarbon degrading microorganisms were isolated from petroleum-contaminated crane service station soil and creosote contaminated wood treatment plant soils in Pretoria area. Bacterial isolates LBP9 and LBP5 isolated from crane service station soil and isolates CB1, CN2, CN3, CN5 isolated from creosote contaminated soil were found to be the most efficient biosurfactant producing strains. The biosurfactant produced by the strains LBP9, LBP5 and CB1 were extracted and characterized by attenuated total reflectance Fourier transform infrared spectroscopy (ATR FTIR) and Thin layer chromatography (TLC). Evaluation of the ability of the LBP9 biosurfactant for applications in enhancing biodegradation of mixed polycyclic aromatic hydrocarbons (PAHs) with a consortium of bacteria indicated that the biosurfactant was able to enhance the removal of significant amount of PAHs from the liquid culture medium at different concentrations. In this study at 400 mg/L amendment of lipopeptide the solubility of Phenanthrene, Fluoranthene and Pyrene was increased to 19.4, 33 and 45.4 times their aqueous solubility, respectively, and the extent of substrate utilization rate of the PAHs was enhanced up to 3 fold in the sole substrate microcosms. A second goal of these experiments was to discern the efficacy of exogenous lipopeptide application and stimulation of in situ biosurfactant production through biostimulation / nutrient amendments in the removing of polycyclic aromatic hydrocarbons (PAH) from creosote PAH contaminated soil. This work also suggests that it may be more practical to stimulate indigenous biosurfactant production within a soil than to add pre-purified compound. In general, the results presented in the studies show the potential of biosurfactants in assisting the bioremediation of polycyclic aromatic hydrocarbon contaminated environmental media in a reasonable timeframe.
Author: Zhongbao Liu
Author: Jia Wei