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Rhamnolipid Biosurfactant Adsorption and Transport in Biochar Amended Agricultural Soil

Title: Rhamnolipid Biosurfactant Adsorption and Transport in Biochar Amended Agricultural Soil.
Name(s): Vu, Kien Anh, author
Chen, Gang, professor directing thesis
Clark, Clayton, committee member
Ahmad, Hafiz, committee member
Huang, Wenrui, committee member
Department of Civil and Environmental Engineering, degree granting department
Florida State University, degree granting institution
Type of Resource: text
Genre: Text
Issuance: monographic
Date Issued: 2013
Publisher: Florida State University
Place of Publication: Tallahassee, Florida
Physical Form: computer
online resource
Extent: 1 online resource
Language(s): English
Abstract/Description: Rhamnolipid biosurfactant is a bacterial biosurfactant produced by several Pseudomonas species, which can wet hydrophobic soils by lowering the cohesive and/or adhesive surface tension, allowing the water to spread out more evenly and better penetrate the hydrophobic soils. Because of its bio-degradability, rhamnolipid biosurfactant applications bring minimal adverse impact on the soil and groundwater as compared with that of chemical wetting agents. Rhamnolipid biosurfactant applications save the water consumptions during agricultural irrigation, especially under draught conditions. This research was designed to investigate the applications of rhamnolipid biosurfactant applications in agricultural soils. Performance of rhamnolipid biosurfactant in intact soil columns collected from agricultural soils was explored and related to the soil and wetting agent properties. In addition, the impact of the organic concentration of wetting agent fate and transport was investigated. The results show that Rhamnolipid biosurfactant may lower the water surface tension (relates to Gibbs free energy of the interaction between rhamnolipid biosurfactant molecules), and wet the agricultural soil samples. The critical micelle concentration (CMC) of rhamnolipid biosurfactant, which is defined as the minimum concentration to form the initiate micelle, is about 40 mg/L. Moreover, the adsorption isotherm of rhamnolipid biosurfactant on the soil is inversely proportional to the increase of concentration of surfactant due to the formation of micelle. But this adsorption isotherm is not dependent to the concentration of biochar-amended soils. The column transport of rhamnolipid biosurfactant is also explored. The results show that the thermodynamic properties of rhamnolipid biosurfactant may control its transport. The retention time of rhamnolipid biosurfactant on the soil changes over the time (pore volume) due to its soprtion, but does not relate to the concentration of biochar-amended soil samples. This transport may also be represented by the advection-dispersion equation with a local equilibrium assumption. The results prove that we may apply rhamnolipid biosurfactant and biochar in the agricultural soils in subtropical area. This application will enhance the water containing ability of soil for crop purpose, and improve the properties of soil.
Identifier: FSU_migr_etd-8654 (IID)
Submitted Note: A Thesis submitted to the Department of Civil and Environmental Engineering in partial fulfillment of the requirements for the degree of Master of Science.
Degree Awarded: Fall Semester, 2013.
Date of Defense: November 1, 2013.
Keywords: Biochar, Biosurfactant, Rhamnolipid, Transport, Transport Modeling
Bibliography Note: Includes bibliographical references.
Advisory Committee: Gang Chen, Professor Directing Thesis; Clayton Clark, Committee Member; Hafiz Ahmad, Committee Member; Wenrui Huang, Committee Member.
Subject(s): Civil engineering
Environmental engineering
Persistent Link to This Record:
Owner Institution: FSU

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Vu, K. A. (2013). Rhamnolipid Biosurfactant Adsorption and Transport in Biochar Amended Agricultural Soil. Retrieved from