Environmental Inorganic Chemistry for Engineers

James G. Speight

• Publisher: Butterworth-Heinemann
• Year: 2017
• Print ISBN: 9780128008331
• eBook ISBN: 9780128011423
• Topic: Technology & Engineering
• Subtopic: Agronomy
• Index: Technology & Engineering

Environmental Inorganic Chemistry for Engineers explains the principles of inorganic contaminant behavior, also applying these principles to explore available remediation technologies, and providing the design, operation, and advantages or disadvantages of the various remediation technologies.Written for environmental engineers and researchers, this reference provides the tools and methods that are imperative to protect and improve the environment. The book's three-part treatment starts with a clear and rigorous exposition of metals, including topics such as preparations, structures and bonding, reactions and properties, and complex formation and sequestering.This coverage is followed by a self-contained section concerning complex formation, sequestering, and organometallics, including hydrides and carbonyls. Part Two, Non-Metals, provides an overview of chemical periodicity and the fundamentals of their structure and properties.- Clearly explains the principles of inorganic contaminant behavior in order to explore available remediation technologies- Provides the design, operation, and advantages or disadvantages of the various remediation technologies- Presents a clear exposition of metals, including topics such as preparations, structures, and bonding, reaction and properties, and complex formation and sequestering

Chapter One

Inorganic Chemicals in the Environment

Abstract

Contamination by inorganic chemicals is a global issue, and such toxic chemicals are found practically in all ecosystems. It is the inappropriate management of such waste (e.g., through haphazard and unregulated disposal) that poses negative impacts on the environment. It is the purpose of this chapter to introduce the reader to the various aspects of inorganic chemicals and the environment and the role that inorganic can play dealing with the various issues of the environment. Throughout the pages of this book, the reader will be presented with the definitions and explanations of terms related to inorganic chemistry and how inorganic chemistry can be understood and used and the effects of the chemical on the environment.

Keywords

Environment; Atmosphere; Aquasphere; Terrestrial biosphere; Inorganic chemistry; Indigenous chemicals; Nonindigenous chemicals; Use and misuse of chemicals

1.1 Introduction

Environmental chemistry focuses on environmental concerns about materials, energy, and production cycles and demonstrates how fundamental chemical principles and methodologies can protect the floral (plant) and faunal (animal, including human) species within the environment (Anastas and Kirchhoff, 2002). More specifically, the principles of chemistry can be used to develop how global sustainability can be supported and maintained. For this, future environmental chemists and environmental engineers must acquire the scientific and technical knowledge to design products and chemical processes. They must also acquire an increased awareness of the environmental impact of chemicals on the environment and develop an enhanced awareness of the importance of sustainable strategies in chemical research and the chemical industry, specifically in the context of this book the inorganic chemicals industry.

By way of introduction, although other classification systems have been published, a general classification of chemical pollutants is based on the chemical structure of the pollutant and includes (i) organic chemical pollutants and (ii) inorganic chemical pollutants. For the purposes of this text, organic chemical pollutants are those chemicals of organic origin or that could be produced by living organisms or are based of matter formed by living organisms (Speight, 2017a).

On the other hand, inorganic chemical pollutants are those chemicals of mineral origin in (not produced by living organisms). In general, substances of mineral origin (such as ceramics, metals, synthetic plastics, and water) as opposed to those of biological or botanical origin (such as crude oil, coal, wood, and food). In addition, minerals are the inorganic, crystalline solid that makes up rocks. With certain exceptions, inorganic substances do not contain carbon or its compounds. In scientific terms, no clear line divides organic and inorganic chemistry.

Inorganic chemistry focuses on the classification of inorganic compounds based on the properties of the compound(s) (Weller et al., 2014). Partly, the classification focuses on the position in the periodic table (Fig. 1.1) of the heaviest element (the element with the highest atomic weight) in the compound, partly by grouping compounds on the basis of structural similarities. Also, inorganic compounds are generally structured by ionic bonds and do not contain carbon chemically bound to hydrogen (hydrocarbons) or any of their derivatives that contain elements such as nitrogen, oxygen, sulfur, and metals. Examples of inorganic compounds include sodium chloride (NaCl) and calcium carbonate (CaCO₃) and pure elements (Cox, 1995).

Fig. 1.1 The periodic table of the elements.

Thus, this text relates to an introduction to the planned and unplanned effects of inorganic chemicals on the various environmental systems. Inorganic chemicals are an essential component of life, but some chemicals are extremely toxic and can severely damage the floral (plant life) and faunal (animal life) environment (Table 1.1).

Table 1.1

Examples of the Classification of Elements According to Their Effects in the Biological Systems^a

Essential

O, C, H, N, P, Na, K, Mg, Cl, Ca, S

Trace

I, Fe, Cu, Zn, Mn, Co, Mo

Nonessential

Al, Sr, Ba, Sn

Toxic

Cd, Pb, Hg

^a Essential elements are necessary for life processes; trace elements are also necessary for life processes; nonessential elements are not essential. If they are absent, other elements may serve the same function; toxic elements disturb the natural functions of the biological system.

As with organic chemicals (Speight, 2017a), contamination of the environment by inorganic chemicals is a global issue, and toxic inorganic chemicals are found practically in all ecosystems because, at the end of the various inorganic chemical life cycles, inorganic chemicals have been either recycled for further use or sent for disposal as chemical waste (Bodek et al., 1988). Current regulations do not permit the unmanaged disposal of chemical waste but, in the past (particularly in the first decades of the 20th century), the inappropriate management of chemical waste (e.g., through haphazard disposal and unregulated burning) has led to a series of negative and lingering impacts on the floral and faunal species that are part of the environment.

Briefly, inorganic chemistry deals with the synthesis and behavior of inorganic and organometallic compounds. The exception to the subdiscipline is the multitude of chemical compounds that fall within the subdiscipline of organic chemistry that covers the multitude of organic compounds (carbon-based compounds, usually containing C

H bonds). The distinction between the two subdisciplines is far from absolute, as there is much overlap within the subdiscipline of organometallic chemistry. Nevertheless, the principles of inorganic chemistry have application in every aspect of the chemical industry, including materials science, catalysis, surfactants, pigments, coatings, medications, fuels, and agriculture.

Many inorganic compounds are ionic compounds, consisting of cations and anions joined by ionic bonding (Chapter 2). An ionic compound is a chemical compound comprising ions (charged species) that are held together by electrostatic forces (ionic bonding). These can be simple ions such as sodium (Na⁺) and chloride (Cl⁻) in sodium chloride, sodium hydroxide that consists of sodium cations (Na⁺) and hydroxide anions (OH⁻), or polyatomic species such as the ammonium ${{(\mathrm{N}\mathrm{H}}_4}^{+})$

and carbonate ${{(\mathrm{C}\mathrm{O}}_3}^{2-})$

ions in ammonium carbonate. In any salt, the proportions of the ions are such that the electric charges cancel out, so that the bulk compound is electrically neutral. The ions are described by their oxidation state, and their ease of formation can be inferred from the ionization potential (for cations) or from the electron affinity (anions) of the parent elements (Chapter 2). Ionic compounds containing hydrogen ions (H⁺) are classified as acids, and those containing basic ions, such as the hydroxide anion (OH⁻) or oxide anion (O²⁻), are classified as bases. Some ions are classed as amphoteric because of the ability of these ions to react with either an acid or a base (Davidson, 1955). This is also true of some compounds with ionic character, typically oxide derivatives or hydroxide derivatives of the less electropositive metals (which results in the compound having significant covalent character), such as zinc oxide (ZnO) aluminum hydroxide [Al(OH)₃], aluminum oxide (Al₂O₃), and lead(II) oxide (PbO).

Important classes of inorganic compounds are the oxide derivatives (

O²⁻), the carbonate derivatives $\left(\text{—}{{\mathrm{C}\mathrm{O}}_3}^{2-}\right)$

, the sulfate derivatives $\left(\text{—}{{\mathrm{SO}}_4}^{2-}\right)$

, and the halide derivatives (such as the chlorides,

Cl⁻¹)—all of these derivatives occur as minerals in the Earth (Chapter 2). Many inorganic compounds are characterized by high melting points (Chapter 4). Other important features include their high melting point and ease of crystallization, where some salts are very soluble in water (such as sodium chloride, NaCl) and crystallize form concentrated solutions of the salt others (such as silica—silicon dioxide, SiO₂). Thus,

Inorganic chemistry: oxygen and metals are the dominant elements.

Organic chemistry: carbon and hydrogen are the dominant elements.

By way of further definition and to alleviate any potential confusion, bioinorganic chemistry (bioinorganic chemistry and biological inorganic chemistry) is a subcategory of chemistry that examines the role of metals in biology systems including the associated environmental issues (Bertini et al., 1994; Fraústo da Silva and Williams, 2001). Thus, bioinorganic chemistry includes the study of both natural phenomena such as the behavior of metalloproteins and artificially introduced metals, including those that are nonessential (Table 1.1) in medicine and toxicology. Many biological processes, such as respiration, depend upon the molecular species that fall within the realm of inorganic chemistry and, as a blend of biochemistry and inorganic chemistry, bioinorganic chemistry is important in elucidating the activity of proteins and the effect of the properties of inorganic compounds as they pertain to the activity and well-being of floral and faunal organisms and an understanding of the various elements inorganic compounds on floral and faunal systems.

As a side but relevant note, it must be assumed that all chemicals are toxic unless proved otherwise. In relation to the environmental effects of inorganic chemicals, consideration must also be given to the effect of the so-called harmless chemicals (the indigenous chemicals and the natural products chemicals) when they are added back to the environment in amounts that exceed the natural abundance. Within the local environment, these chemicals will...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Author Biography
• Preface
• Chapter One: Inorganic Chemicals in the Environment
• Chapter Two: Inorganic Chemistry
• Chapter Three: Industrial Inorganic Chemistry
• Chapter Four: Properties of Inorganic Compounds
• Chapter Five: Sources and Types of Inorganic Pollutants
• Chapter Six: Introduction Into the Environment
• Chapter Seven: Transformation of Inorganic Chemicals in the Environment
• Chapter Eight: Environmental Regulations
• Chapter Nine: Removal of Inorganic Compounds From the Environment
• Appendix
• Conversion Factors
• Glossary
• Index