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2024 | Book

Sustainability in Ground Improvement: The Case of Xanthan Gum Biopolymer

Authors: Abdel-Mohsen O. Mohamed, Brendan C. O’Kelly, Amin Soltani

Publisher: Springer Nature Switzerland

Book Series : Green Energy and Technology

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About this book

Sustainable soil stabilization solutions aim to maintain a perfect balance between infrastructure performance and the social, economic and ecological processes required to sustain human equity, diversity, and the functionality of natural systems. To this end, biopolymers, either chemically synthesized from biological matter or biosynthesized by living organisms, are exhibiting great promise as a financially competitive and green alternative for conventional calcium-based binders. Recent experimental studies have shown that soils stabilized by polysaccharide-type biopolymers, such as xanthan gum (XG), exhibit a variety of promising physical and mechanical treatments, including improved water-retention capacity, reduced compressibility and hydraulic conductivity, enhanced shear strength, and improved resistance against wind/water erosion. Despite these advancements, the existing literature reveals numerous inconsistencies, and a thorough understanding of the behaviour/properties of XG-treated soils under diverse loading and environmental conditions remains somewhat elusive. More importantly, there remains a notable gap in understanding how different factors affect the interactions between XG and various soil types throughout the processes of mixing, curing, and later environmental exposure. This book represents the first of its kind, offering a comprehensive, fundamental overview of the current state of XG usage for sustainable ground improvement, while also identifying future research directions towards addressing existing gaps in knowledge and application.

Table of Contents

Frontmatter
Chapter 1. Unraveling the Challenges of Xanthan Gum Soil Stabilization
Abstract
Soil stabilization is a crucial aspect of civil engineering and construction projects, aimed at improving the engineering properties of soil materials. Xanthan gum (XG), a biopolymer derived from fermentation processes, has gained widespread attention as a potential soil-stabilizing agent due to its unique rheological properties. This chapter provides an overview of the traditional soil stabilization techniques, followed by outlining the potential benefits and main technical issues of employing XG as a soil-stabilizing agent. In addition, the chapter discusses the overall challenges and considerations associated with the utilization of XG for soil stabilization purposes, including its effectiveness, environmental impact, cost implications, and compatibility with different soil types. By examining these factors, engineers and researchers can make informed decisions regarding the application of XG in soil stabilization projects. The chapter concludes with an outline of the topics that are discussed in the later chapters of this book.
Abdel-Mohsen O. Mohamed, Brendan C. O’Kelly, Amin Soltani
Chapter 2. Xanthan Gum Production and Structure
Abstract
In nature, microbial polysaccharides are essential components of biofilms, which are the main support form of life on earth (Flemming et al. in Nat Rev Microbiol 14:563–575, 2016), and microorganisms’ lifestyle (Penesyan et al. in NPJ Biofilms Microbiomes 5:34, 2019). These biofilms contain microbial cells that are fixed within a self-produced matrix of extracellular polymeric substances, which are composed of polysaccharides, proteins, lipids, and nucleic acids (Powell et al. in NPJ Biofilms Microbiomes 29:13, 2018). The relative composition and molecular structure of these polymeric substances vary depending on the producing microorganism and the environmental conditions (e.g., fluid chemistry, pressure, and temperature). Therefore, depending on the potential industrial application, different industrial fermentation processes can be adopted.
Abdel-Mohsen O. Mohamed, Brendan C. O’Kelly, Amin Soltani
Chapter 3. Rheology of Xanthan Gum Aqueous Solution
Abstract
Xanthan Gum (XG) is a polysaccharide that is produced by the bacterium Xanthomonas campestris through fermentation, as discussed in Chap. 2. The practical use of XG in various industries, including food processing, pharmaceuticals, cosmetics, agriculture, and engineering, is mainly a result of its ability to induce high viscosity at low polymer concentrations in aqueous environments. It can modify the rheological behavior of fluids (i.e., the flow and deformation of XG suspension under applied stresses) by acting as a thickener and stabilizer. For the former, XG is a highly effective thickening agent. It forms a network of long-chain polymers that entrap water and increase the viscosity of the fluid. As elaborated later, the thickening properties of XG are dependent on various factors, such as XG concentration, the solution pH and temperature, shear rate, and the presence of salts and/or other chemical additives. Moreover, the rheological behavior of XG solutions is pseudoplastic, which means that the viscosity decreases with increasing shear rate. Additionally, XG is an effective stabilizer, particularly in emulsions. It can stabilize oil-in-water emulsions by forming a protective layer around the oil droplets, preventing them from coalescing. XG can also stabilize suspensions by preventing settling and maintaining a uniform distribution of particles.
Abdel-Mohsen O. Mohamed, Brendan C. O’Kelly, Amin Soltani
Chapter 4. Xanthan Gum–Soil Interactions
Abstract
To the civil engineer, soil is any uncemented or weakly cemented accumulation of mineral grains formed by physical and/or chemical weathering of rocks, with the void spaces between the solids containing water (pore water) and/or air. Chemical weathering causes changes in mineral form of the parent rock leading to the formation of groups of colloidal crystalline particles (i.e., < 2-μm sized particles according to their civil engineering classification) known as clay minerals. Basic structural units of most clay minerals are a silicon–oxygen tetrahedron and an aluminum–hydroxyl octahedron, with the valency imbalances in both units resulting in net negative charges.
Abdel-Mohsen O. Mohamed, Brendan C. O’Kelly, Amin Soltani
Chapter 5. Stability of Xanthan Gum–Soil Cohesive Networks
Abstract
As discussed in Chaps. 2 and 3, Xanthan Gum (XG) is a high-molecular-weight polysaccharide consisting of a repeating pentasaccharide unit, composed of glucose, mannose, and glucuronic acids, and which are linked by β(1,4)-glycosidic bonds. The anionic carboxyl and hydroxyl groups on the XG molecule make it highly hydrophilic, and it can interact with various compounds, including water and metal ions. XG has excellent water-holding capacity, thickening ability and stabilizing properties, making it widely used in various applications, including agriculture, food processing, pharmaceutical, environmental and geotechnical engineering, and petroleum industries. In recent years, XG has also been increasingly investigated as a soil stabilizer to improve the physical and mechanical properties of soils.
Abdel-Mohsen O. Mohamed, Brendan C. O’Kelly, Amin Soltani
Chapter 6. Strength and Compressibility of Xanthan Gum-Treated Soils
Abstract
Xanthan gum (XG) is a high molecular weight anionic polysaccharide produced by the bacterium Xanthomonas campestris. Because of its unique rheological properties (as discussed in Chap. 3), XG is widely employed as a thickening, stabilizing, and gelling agent for a variety of industrial applications, including, food processing, cosmetics, pharmaceuticals, and oil and gas. Recently, XG has been explored as a chemical soil-stabilizing agent, owing to its ability to form a three-dimensional reinforcement-type network within soils for enhancing their geo-mechanical properties.
Abdel-Mohsen O. Mohamed, Brendan C. O’Kelly, Amin Soltani
Chapter 7. Xanthan Gum (XG) Sorption and Hydraulic Conductivity of XG-Treated Soils
Abstract
As discussed in Chaps. 4, 5, and 6, properties of xanthan gum (XG), soil, and soil solution influence adsorption and aggregative success of XG–soil structure. Molecular weight, size, conformation and surface charge are all aspects of the XG that affect its sorption onto the soil particles. XG interacts more with the clay fraction of soils; as such, the particle surface area, type and amount of clay, soil structure, and pore-size distribution are soil attributes that influence the nature and level of XG sorption onto clay particle surfaces. The pH level, ionic strength, and electrolyte concentration of the soil solution also influence the sorption of XG onto clays.
Abdel-Mohsen O. Mohamed, Brendan C. O’Kelly, Amin Soltani
Metadata
Title
Sustainability in Ground Improvement: The Case of Xanthan Gum Biopolymer
Authors
Abdel-Mohsen O. Mohamed
Brendan C. O’Kelly
Amin Soltani
Copyright Year
2024
Electronic ISBN
978-3-031-75313-8
Print ISBN
978-3-031-75312-1
DOI
https://doi.org/10.1007/978-3-031-75313-8