Reaction Mechanisms in Environmental Engineering

Analysis and Prediction

James G. Speight

• Publisher: Butterworth-Heinemann
• Year: 2018
• Print ISBN:
  9780128005392
• eBook ISBN:
  9780128006672
• Topic: Technology & Engineering
• Subtopic: Agronomy
• Index: Technology & Engineering

Reaction Mechanisms in Environmental Engineering: Analysis and Prediction describes the principles that govern chemical reactivity and demonstrates how these principles are used to yield more accurate predictions. The book will help users increase accuracy in analyzing and predicting the speed of pollutant conversion in engineered systems, such as water and wastewater treatment plants, or in natural systems, such as lakes and aquifers receiving industrial pollution. Using examples from air, water and soil, the book begins with a clear exposition of the properties of environmental and inorganic organic chemicals that is followed by partitioning and sorption processes and sorption and transformation processes. Kinetic principles are used to calculate or estimate the pollutants' half-lives, while physical-chemical properties of organic pollutants are used to estimate transformation mechanisms and rates. The book emphasizes how to develop an understanding of how physico-chemical and structural properties relate to transformations of organic pollutants. - Offers a one-stop source for analyzing and predicting the speed of organic and inorganic reaction mechanisms for air, water and soil - Provides the tools and methods for increased accuracy in analyzing and predicting the speed of pollutant conversion in engineered systems - Uses kinetic principles and the physical-chemical properties of organic pollutants to estimate transformation mechanisms and rates

Part I

Introduction

Outline

Chapter 1. Environmental Chemistry

Chapter 2. Chemicals in the Environment

Chapter 3. Chemical and Physical Properties

Chapter 4. Mechanisms of Introduction Into the Environment

Chapter 1

Environmental Chemistry

Abstract

This chapter introduces the reader to the study of the environment and the concept that such a study must be interdisciplinary of physical, chemical, and biological sciences. Some of the fields of interest are: (1) chemistry, which includes: constitution of environmental matter (air, water, soil, and selected chemicals), materials, and energy balances, (2) biology, which includes: microbiology, botany, zoology, sociology, and biodiversity, and (3) physics, which includes: meteorology, climatology, hydrology, oceanography, and the oceans–atmosphere system. The focus of this book is the category dealing with chemistry, particularly the reaction mechanisms of chemical pollutants with the environment and the various aspects of chemical remediation, as well as the interactions of any chemicals used in the remediation process.

Keywords

Chemical transformations; Environment; The aquasphere; The atmosphere; The lithosphere

1. Introduction

Environmental chemistry is the study of the chemical and biochemical phenomena that occur in natural places and is the study of the sources, reactions, transport, effects, and fates of chemical species in the air, water, and soil environments, as well as the effect of human activity and biological activity on these (Tinsley, 2004). More specifically, environmental chemistry is the study of chemical processes occurring in the environment which are impacted by humankind's activities. These impacts may be felt on a local scale, through the presence of urban air pollutants or toxic substances arising from a chemical waste site, or on a global scale, through depletion of stratospheric ozone or global warming.

Furthermore, the study of the environment is an interdisciplinary subject that integrates physical, chemical, and biological sciences; some of the fields of interest are: (1) chemistry, which includes: constitution of environmental matter (air, water, soil, and selected chemicals), materials, and energy balances, (2) biology, which includes: microbiology, botany, zoology, sociology, and biodiversity, and (3) physics, which includes: meteorology, climatology, hydrology, oceanography, and the oceans–atmosphere system. The focus of this book is the category dealing with chemistry, particularly the reaction mechanisms of chemical pollutants with the environment and the various aspects of chemical remediation, as well as the interactions of any chemical used in the remediation process.

Almost any chemical from natural sources or anthropogenic sources can pollute the environment. However, it is the synthetic and other industrial chemicals that are emphasized here. Whether the chemical is present in a small amount or present in the ecosystem in large amount (the effective amount of the chemical depending upon the chemical), the potential for pollution is real (Table 1.1) (Hill, 2010). The presence of a chemical in a large amount causes acute toxicity in the form of having an adverse effect on the flora and fauna of an ecosystem. On the other hand, the presence of a chemical in a small amount can give rise to chronic effects, in which the flora and fauna will suffer when exposed to the long-term exposure to very low concentrations of a substance.

Table 1.1

General Categories of Types of Pollutants

Category	Examples
Organic chemicals	Polychlorinated biphenyls (PCBs), oil, many pesticides
Inorganic chemicals	Salts, nitrate, metals and their salts
Organometallic chemicals	Methylmercury, tributyltin, tetraethyl lead
Acids^a	Sulfuric, nitric, hydrochloric, acetic
Physical	Eroded soil, trash
Radiological	Radon, radium, uranium
Biological	Microorganisms, pollen

^a Acids, as well as physical and radioactive pollutants, can be either organic or inorganic— sulfuric acid is inorganic, acetic acid (found in vinegar) is organic. Biological pollutants are mostly organic chemicals, but often contain inorganic chemicals.

Furthermore, pollution by chemicals is a definitive case of habitat destruction (Miller, 1984; Speight, 2017a,b) and involves (predominantly) chemical destruction rather than the more obvious physical destruction. The overriding theme of the definition is the ability (or inability) of the environment to absorb and adapt to changes brought about by human activities. Thus, environmental pollution occurs when the environment is unable to accept, process, and neutralize any harmful byproduct of human activities (such as the gases that contribute to acid rain).

Briefly, in the context of this book, a pollutant is a (1) nonindigenous chemical that is present in an ecosystem or (2) an indigenous chemical that is present in an ecosystem in greater than the natural concentration. Both types of pollutants are the result of human activity and have an overall detrimental effect upon the ecosystem or upon floral (plants) or faunal (animals, including humans) species in an ecosystem. In addition, the term ecosystem represents an assembly of mutually interacting organisms and their environment in which materials are interchanged in a largely cyclical manner and is, essentially, a community of organisms together with their physical environment, which can be viewed as a system of interacting and interdependent relationships. This can also include processes such as the cycling of chemical elements (such as heavy metals) and chemical compounds through the floral and faunal components of the system.

A contaminant is a chemical that is present in nature at a level higher than fixed levels or that would not otherwise be there. This may be due to human activity and bioactivity. The term contaminant is often us...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Biography
• Preface
• Part I. Introduction
• Part II. Transformation Processes
• Part III. Conversion Tables and Glossary
• Index