Designed nanomaterials

Nanomaterials for water treatment technologies

       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 which relate to the 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, and quantum confinement effect. Most applications discussed below are still in the stage of laboratory research.

 

        Nanotechnology provides leapfrogging opportunities to develop next-generation water supply systems. In the developed world, near-term applications include solving problems with existing treatment processes (e.g., DBPs, emerging contaminants, and membrane fouling) through system retrofitting. Many nanotechnologies can enhance treatment capabilities and efficiency with minimum alterations to the existing infrastructure, enabling the use of nonconventional water sources such as wastewater for different reuse scenarios. Nanotechnology-enabled POU systems can polish tap water for drinking or other high-end use, alleviating the risk associated with secondary contamination in the distribution system. In developing countries, nanotechnology would enable POU systems that are easy to operate, maintain, and replace, and can be tailored to specific treatment needs with minimal use of electricity or chemicals.

 

        In the future, nanotechnology will likely play an important role in reshaping water supply systems to be more sustainable and smarter (i.e., differentiating and responding to changes in available water resources, and water quality and quantity requirements). This will most likely be achieved by centralized basic treatment (e.g., suspended solids removal) near the source water, complemented by differential treatment and water reuse at the point of use (residential communities, farms, industries, etc). The large variety of nanomaterials makes it possible to have modular units for different treatment goals, which allow easy control of functionality and capacity by plugging in or pulling out modules. As the same treatment schemes for differential reuse of wastewater can be applied to treat natural water to varying quality, local combined water treatment and reuse can be realized. Furthermore, future nanotechnology-enabled systems might function on-demand by detecting contaminants in real time and triggering corresponding treatment when needed.

 

Reference
       Qu X, Alvarez P J J, Li Q. Applications of nanotechnology in water and wastewater treatment[J]. Water research, 2013, 47(12): 3931-3946.
       Qu X, Brame J, Li Q, et al. Nanotechnology for a safe and sustainable water supply: enabling integrated water treatment and reuse[J]. Accounts of chemical research, 2012, 46(3): 834-843.