Preface

Food, beverages, medicines, cosmetics, and detergents are ubiquitous in daily life. A close look at these diverse products reveals one common ingredient: surfactants. Because of its their wide and expansive applications, surfactants are a billion-dollar industry that is estimated to reach a market size of USD 57.8 billion by 2028, USD 24.8 billion of which will come from the market for natural surfactants. Although a large portion of the existing surfactant market is essentially synthetic, the availability of natural surfactants at the commercial scales and the growing need for them is directly related to the increasing consciousness of environmental change and the need to mitigate it. Natural surfactants derived from renewable resources like vegetable crop oils are considered environmentally "green and safe" because of their low eco-toxicity in addition to their highly biodegradable characteristics in contrast to most synthetic surfactants that have long degradation times, often several months, allowing the build-up of toxic waste in natural underwater reservoirs, rivers, and soil.

This book is a compilation of several chapters that highlight the use of specific surfactants and their functional properties in different applications that range from enhanced oil recovery (EOR) from ocean beds to nano-emulsion-based drug delivery systems for the treatment of cancer. Keeping in view a large audience consisting of experts as well as researchers new to the subject, we have avoided all mathematical derivations of formulas used across the book, but appropriate references have been provided for the reader interested in equations.

This volume consists of eight chapters presenting various perspectives and insights on both synthetic and natural surfactants used in different applications.

Chapter 1 examines the structure-property relationship connecting surface tension, torque, and bending rigidity of interfacial films to predict the micro-emulsion characteristics of an oil-surfactant-brine micro-emulsion representing an EOR system.

Chapter 2 studies the effects of sodium lignosulphonate (SLS) produced from sugar cane bagasse, which is a waste material, on the yield of oil recovered EOR processes as a function of SLS concentration and at different salinities. This study suggests the feasibility of profitably using bagasse that is usually burnt and that causes massive atmospheric pollution.

Chapter 3 compares the detergency of saponins extracted from tea leaves on fabrics with the detergency of a well-known commercial product. The results reveal comparable benefits and suggest the possibility of replacing a slowly degrading synthetic surfactant like lauryl alcohol benzyl sulphonic acid (LABSA) with saponins that are natural, green, and readily biodegradable.

Chapter 4 establishes the advantages of using microemulsion systems for drug delivery in the treatment of cancer. These systems are thermodynamically stable and the presence of lipids enhances the bioavailability of drugs resulting in quicker alleviation of symptoms.

Chapter 5 provides an overview of biosurfactants derived from renewable feedstock like vegetable oils and sugar and the advantages of using these industrially. It also discusses the various challenges in bulk production of these materials.

Chapter 6 examines the interaction of the antiulcer drug roxatidine acetate loaded on chitosan nanoparticles with serum albumin. It investigates the influence of a surfactant Tween 80 in the release of the active ingredient using fluorescence and circular dichroism spectroscopy.

Chapter 7 discusses the presence of microplastics and nanoparticles in water bodies and ecotoxicity arising therefrom. This study demonstrates that polyethylene and titanium dioxide nanoparticles largely enhance the ecotoxicity of water bodies endangering aquatic life.

Chapter 8 highlights the importance of surfactant-enhanced remediation of soil contaminants, especially hydrophobic organic contaminants.

I take this opportunity to thank all the authors for their excellent contributions and the staff at IntechOpen for their assistance throughout the publication process. I also wish to thank my wife Malabika and my two children Sourav and Siddharth for their help and cooperation. I dedicate this book to the loving memory of my parents.

> **Dr. Ashim Kumar Dutta** Vice President (R&D), India Glycols Limited,

> > Uttarakhand, India

## **Chapter 1**
