Preface Free

Agriculture and industrial developments are not possible without the indispensable element water. All living and non-living things require water for their existence in one way or another. So, if somebody says that ‘water is the liquid of life’, it is absolutely correct. Nobody can live without water.

The population explosion, increasing urbanization and industrialization are the major reasons for the depletion of water availability worldwide and that's why the water crisis has become a global challenge today. Scientists, policy makers and academicians are continuously trying hard to address this problem to the best of their knowledge and abilities, but without complete success.

Besides the water crisis, the availability of ‘safe water’ is another associated challenge. Because of various types of pollutants and impurities present in water, whatever water is available is not always ‘safe’. Unfortunately drinking such ‘unsafe’ water is the fate of billions of people around the world and pure water is always a ‘dream’ for them.

Dissolved solids, synthetic dyes, agriculture runoffs, industrial effluents and microorganisms are a few of the things responsible for making water unsafe. The presence of heavy metals is an add-on to this list, and these are so dangerous that they may actually lead to death. Metals such as arsenic, cadmium, chromium, copper, lead, mercury, nickel and zinc are commonly found at contaminated sites and in aqueous systems. For example, arsenic poisoning claims thousands of deaths every year in Bangladesh and West Bengal in India, while lead is very toxic to living organisms, accumulating in the bones, brain, kidney and muscles, and may be the cause of many serious disorders such as anaemia, kidney diseases, nervous disorders, sickness and even death.

The presence of heavy metals in water is due to both natural and anthropogenic sources. Natural sources may include parent rocks and metallic ores and, on the other hand, agriculture (fertilizers, animal manures, pesticides), metallurgy (mining, smelting, metal finishing), energy production (leaded gasoline, battery manufacture, power plants), microelectronics, sewage sludge and scrap disposal can be included in the anthropogenic sources.

Removal of these heavy metals is a big problem for everyone. Examples of the many techniques being tried to achieve this include biosorption, bioremediation, phytoremediation, photocatalytic processes, use of functionalized magnetic nanoparticles and use of industrial and agricultural waste.

This book is a sincere effort to showcase the latest research in the field of heavy metals removal, written by leading scientists and researchers. At this point in time I express my gratitude to all contributors who made this volume possible. I hope that the chapters presented will be a good source of reference material for scientists in their further research and development.

Also, I hope that this book provides an insightful text on the theme of ‘heavy metals removal’ and processes that are being studied, optimized and developed to sustain both mankind and nature.

I sincerely welcome feedback from all my valuable readers and critics.

Happy reading!

Sanjay K. Sharma

Jaipur, India