Nano-Ag has been used for different reasons in consumer and commercial products over the past century. Nanosilver has appeared in an increasingly wide range of U.S. products, including athletic clothing, bed and bath linens, cosmetics, baby bottles, stuffed animals etc. It’s also used in hospital equipment. In Southeast Asia, nanosilver is used even more commonly and often openly. It has been sprayed in Hong Kong subways promoted with Korean toothpaste.
Cu is a known antibiotic material and is recently found effective in treating drinking water, industrial effluent, sewage, and to reduce disease transmission in public places such as washrooms. The Cu NPs are attached to a vermiculite material which is a mineral that is stable and used under extensively as filler in fireproof materials, plastics, paints and lightweight concrete.
New age sensors promise to be simple, portable, disposable, low power-consuming and inexpensive devices. Nanotech-paper based sensors are particularly promising for their affordability. SWCNTs trapped in paper with Au electrodes shows a detection limit of 20ppm of ammonia gas with a quick response.
Sapwood is comprised of xylem, a porous tissue that conducts sap from a tree’s roots to its crown through a system of vessels and pores. Such a pit-membrane is effective filters of contaminants. For example, a direct observation of 99% NP filtration down to 70nm is possible. This includes bacteria down to 200nm such as E. coli. This method could be used to treat up to 4L of water per day.
With over 50% of our physical weight being water, every human being needs to drink to stay healthy and fit. Pollution is threatening this vital life source for many countries. Particular nanostructures have an interesting promise to purify our waters.
Firstly, water purification membranes are typically divided into four categories according to pore size:
- microfiltration (MF, < few microns)
- ultrafiltration (UF, < 100 nm)
- nanofiltration (NF, < 10 nm)
- reverse osmosis (RO, < 1 nm)
Graphene Plus materials are effective at adsorbing organic pollutants such as hydrocarbons from water, soils and air. The first treatment project started in 2014. A Romanian former refinery site was to have its waster treated petroleum hydrocarbons. Approval was granted by the Italian Environmental Ministry for the use these products in oil spills clean-up activities.
Nanosurfaces may be functionalized and perhaps combined with other materials to create a nanoscavenger. For example, a nanofiber may be co-synthesized with functional additives such as quaternary ammonium salt (QAS) biocides, polyoxometalates (POMs), fullerenes and phthalocyanines capable of neutralizing chemical and biological agents. Magnetism may also be used to recover the nanoscavengers and perhaps subsequently extract antibiotics, precious metals and other caught substances for subsequent use.
Zeolite layered and silica doped nickel ferrite magnetic cores have been found particularly useful to eliminate toxic ions of heavy metals such as lead and cadmium from polluted water.