Nanotechnology in the Environment—The Good, the Bad, and the Ugly

Nanotechnology is the ability to work at the molecular level, atom by atom, to create larger structures with fundamentally new molecular organization, novel properties, and functions. Engineered nanomaterials, typically a tenth the size of a human cell, are currently being used for a broad range of novel applications, including drug delivery, tissue engineering, tumor treatment, imaging, catalysis, detectors/sensors, and energy storage and transmission devices. Although some nanomaterials have been synthesized since the 1980s, their widespread production is relatively recent and their market size is expected to reach $1 trillion within 10 to 15 years. Such rapid growth suggests the potential for large environmental footprints, some of which will be good, some bad, and some ugly. On the good side, some nanomaterials hold great promise for reducing waste production, cleaning up industrial contamination, providing potable water, and improving the efficacy of energy production and use. The high potential to improve environmental technologies some of which date back to the Victorian era is intrinsically related to the small size of engineered nanomaterials, which results in significantly different properties than the associated bulk materials. Small size translates into a large surface to volume ratio, which implies greater opportunity to interact with environmental pollutants. In a sense, nanomaterials are “all surface.” This can be a highly desirable property for water, wastewater, and hazardous waste treatment. Some nanomaterials can be superior adsorbents or catalysts that remove pollutants more efficiently and at a substantially lower cost than current materialintensive approaches such as ion exchange resins and activated carbon adsorption. Nanotechnology also offers the potential for multifunctional materials, such as nano-architectured membranes for water treatment that incorporate chemically reactive nanomaterials to accomplish both separation and degradation of pollutants and enhance antifouling properties. The good news is that many of our colleagues are making significant progress toward the development of environmental nanotechnologies. These include nanosized iron for reductive treatment of chlorinated solvent DNAPLs, nanomagnetite for the removal of arsenic by sorption and magnetic separation, high-performance nanoscale Pd/ Au catalysts for treating particularly challenging contaminants in water that must be removed to a very low level, and novel advanced oxidation and disinfection approaches, to name a few. We hope to publish more papers in these emerging areas of research in the near future. On the bad side, the environment will be increasingly prone to