ABSTRACT
Nanomaterials are typically defined as materials smaller than 100 nm in at least one dimension. At this scale, materials often possess novel size-dependent properties different from their large counterparts, many of which have been explored for applications in water and wastewater treatment. Some of these applications utilize the smoothly scalable size-dependent properties of nanomaterials that relate to their high specific surface area, such as fast dissolution, high reactivity, and strong sorption. Others take advantage of their discontinuous properties, such as superparamagnetism, localized surface plasmon resonance (SPR), and quantum confinement effect. Most applications discussed in this chapter are still in the stage of laboratory research. Pilot-tested or field-tested exceptions will
1.1 Introduction ..............................................................................................................................1 1.2 Nanoremediation Using TiO2 Nanoparticles ............................................................................3 1.3 Gold Nanoparticles for Nanoremediation .................................................................................6 1.4 Zerovalent Iron Nanoparticles ..................................................................................................6 1.5 Silicon Oxide Nanoparticles for Nanoremediation ..................................................................7 1.6 Other Materials for Nanoremediation ......................................................................................9 1.8 Conclusion .............................................................................................................................. 13 References ........................................................................................................................................ 13
be noted in the text. According to Bhattacharyyal et al. (2010), the word “nano” is developed from the Greek word meaning “dwarf.” In more technical terms, the word “nano” means 10−9, or one billionth of something. For example, a virus is roughly 100 nm in size (Cao 2004; World Health Organization and UNICEF 2013; U.S. Bureau of Remediation and Sandia National Laboratories 2003; Mara 2003). Naturally, the word nanotechnology evolved due to the use of nanometer-sized particles (sizes of 1-100 nm). The potential uses and benefits of nanotechnology are enormous. Environmental pollution is a serious day-to-day problem faced by the developing and developed nations in the world. Air, water, and solid waste pollution due to anthropogenic sources contribute a major share to the overall imbalance of the ecosystem. Water is the most essential substance for all life on Earth and a precious resource for human civilization. Reliable access to clean and affordable water is considered one of the most basic humanitarian goals, and remains a major global challenge for the twenty-first century. Water has a broad impact on all aspects of human life including, but not limited to, health, food, energy, and the economy. In addition to the environmental, economic, and social impacts of poor water supply and sanitation, the supply of fresh water is essential for the safety of children and the poor (Cloete et al. 2010; Elimelech and Phillip 2011; Mara 2003). It is estimated that 10-20 million people die every year due to waterborne diseases, and nonfatal infections cause the death of more than 200 million people every year. Every day, about 5000-6000 children die due to the water-related problem of diarrhea. There are currently more than 0.78 billion people around the world who do not have access to safe water resources (Moore et al. 2003; Montgomery and Elimelech 2007; Eshel 2007), resulting in major health problems. It is estimated that more than one billion people in the world lack access to safe water, and within a couple of decades the current water supply will decrease by one-third. The increasingly stringent water quality standards, compounded by emerging contaminants, have brought new scrutiny to existing water treatment and distribution systems widely established in developed countries. The rapidly growing global population and the improvement in living standards continuously drive up demand. Moreover, global climate change accentuates the already uneven distribution of fresh water, destabilizing the supply. Growing pressure on water supplies makes the use of unconventional water sources (e.g., stormwater, contaminated fresh water, brackish water, wastewater, and seawater) a new norm, especially in historically water-stressed regions. Furthermore, current water and wastewater treatment technologies and infrastructure are reaching their limit for the provision of adequate water quality to meet human and environmental needs.
