In the environmental technology industry alone, nanomaterials will enable new means of reducing the production of industrial wastes, using resources more sparingly, remediating industrial contamination, providing potable water, and improving the efficiency of energy production. This paper discusses three new kinds of nanotechnology materials that should be developed in the future: Membranes, oxidants, and adsorbents. Nanoscale control of membrane architecture may yield membranes of greater selectivity and lower cost in both water treatment and water fabrication. Fullerene-based oxidant nanomaterials such as C60 have a high electron affinity and reactivity, and are capable of producing reactive oxygen species such as singlet oxygen and superoxides. Fullerenes might be used in engineered systems to photocatalytically oxidize organic contaminants, or inhibit or inactivate microbes. The ability to tailor surfaces can help to increase adsorbing capacities or recognize specific contaminants. The potential environmental risks are that nanomaterials could interact with biota and that their toxicity adversely may affect ecosystems. As nanochemistry emerges as an important force behind new environmental technologies, we are also presented with the responsibility of considering the environmental implications of an emerging technology at its inception and taking every precaution to ensure that these technologies develop as tools of sustainability rather than becoming future liabilities.