Silver is among the widely used metal in the world.  Its metallic properties make it a great conductor.  Its anti-microbial properties are also being exploited in several applications.   Reducing silver to nano-sized particles helps to make the element highly effective, making it more in demand for several use in the industry of medicine and technology.  Currently, there are many silver nanoparticles industrial uses that resulted in a boost in its demand and production.  Silver nanoparticles can be used as an ingredient for electroconduit slurry, air purifiers, water purifiers, and even as an ingredient for inks used in inkjets.

According to the Institute of silver, industrial demand for silver metal grew to as much as 7%, with 6% coming from the sector of electric and electronic sector.  Companies such as BASF are currently experimenting with industrial uses of silver nanoparticles.  Membrane switches are made with silver inks, as with electrical circuits in printed electronics.  Inks with silver nanoparticles are being developed by companies such as Bayer Material Science for an advanced generation of ink-jet printers that can be used to print applications used for electronic use for sensors, actuators and RFID systems. 

Several companies such as Earthrise Capital Partners, LLC and Nanomaterials Investors, LLC are currently funding research for silver nanoparticles industrial uses.  The investment given also includes how to market inks with silver nanoparticles to consumers.  Currently, the silver nanoparticles being produced are suitable for use with transistors, conductors, and semiconductors.  Several synthetic procedures are being tested in order to produce silver nanoparticles at low temperatures which is cost efficient without causing any change in the physical, optical, and catalytic properties.  Low temperate procedures make silver nanoparticles perfect for printing electronics on paper and plastics, materials that can easily be destroyed when exposed to high temperatures. 

A potential for silver nanoparticles industrial use is making it as a coating on polyurethane (PU) foams.   The material is ideal as it can be washed, dried, and stored for long periods of time and still retain the same number of nanoparticles.  The material is tested as an element in water filtration to eliminate bacteria.  The output of the water was free of bacteria when the water introduced to the system had a bacterial load of 1 x 10⁵-1 x 10⁶ CFU/mL.  Domestic use of the system is seen as possible for bacteria were not present in water checked in a flow rate of 0.5 L/min.  The filtered water samples were further tested to validate the data and the result of the sample was acceptable within WHO standards for safe drinking water.  The system also shows possibility of use but not limited to, air filtration, air quality management both for domestic and industrial setting, as well as anti-bacterial packaging. Chemical compounds used for the preparation of silver nanoparticle coated foams are easily available, non-toxic, and cost-effective.  The process involved is also simple, making this form of application of silver nanoparticles easy for third-world countries to adopt where technology is limited but bacterial contamination is widely apparent. 

Samsung is causing a stir in the industrial world by creating appliances that emit silver nanoparticles.  SilverCare washing machines are made with sterling silver plates located inside.  It also emits 400 billion silver nanoparticle ions through electrolization, penetrating every fiber of the clothes washed.  This results in washed clothes that are clean, and also sterile as bacteria are eliminated when they come in contact with the silver nanoparticles.  The press release of this washing machine states that clothes will not smell as much (or not smell at all) when they come in contact with sweat because of the absence of bacteria.  Baby clothes are kept clean and bacteria-free without any irritating chemicals that leave residue between the fibers.  Delicate clothing such as underwear, lingerie, and other clothing that cannot be subject to high temperatures are protected with a coating of silver nanoparticle for up to one month.

Industrialists are not worried about the long-term effects of silver introduced to the environment with every use of silver nanoparticle-coated appliance and the synthesis of silver nanoparticles.  There were studies that observed significant mutations in fish exposed to silver nanoparticles, but it is not clear if the mutation is caused by the presence of silver, or presence of a nanoparticle.  Tests were also done on the effects of silver nanoparticles on nitrifying bacteria, and it was found that the nanosilver inhibited its growth by up to 50%.  This test was done by loading 100% of silver nanoparticles with a peak concentration of 0.75 mg/L that lasted for 12 hours. 

In an experiment on shock loading of 100% AgNPs (lasting for 12 hours), a peak concentration of 0.75 mg/L total Ag in the activated sludge basin (more than 95% associated with biomass) was detected, and about 50% nitrifying bacterial growth inhibition (or nitrification inhibition) accompanied with a slight accumulation of nitrite concentration in wastewater effluent was observed.  An accompanied increase in nitrate levels indicates that if released silver nanoparticles reach threshold levels, waste water treatment will be drastically affected.   This experiment concluded that silver nanoparticles are highly toxic to the beneficial bacteria that remove ammonia in sewage waters.  If the growth of the nitrifying bacteria is halted, the ammonia will eventually accumulate rendering the water toxic to all life forms.  Massive fish deaths would result in river waters where the silver nanoparticles are released.  Sludge from the treatment plant is commonly recycled for use as fertilizer in field crops.  If the sludge contains silver nanoparticles, using it for soil amendment will only harm the soil as the nanoparticles will also kill beneficial bacteria that helps nourish and protect crops from disease and pests.  The Water Environment Research Foundation gave $150,000 to Zhiqiang Hu to establish when silver nanoparticles will begin to cause harm on waste water treatment.  Hu is an assistant professor of civil and environmental engineering in MU’s College of Engineering.  It is estimated that the follow-up research will be concluded within this year (2010).   

There are certainly some advantages of silver nanoparticles industrial uses.  Still, the effects of silver nanoparticle synthesis and release of the nanoparticles in the environment must be closely studied as well. 

http://www.gzjiechuang.com.cn/en/cpzs_con.aspx?id=93

Silver and its importance to printed electronics:  http://www.printed-electronics-reports.com/press/205.shtml

This War Against Germs Has a Silver Lining: http://online.wsj.com/article/SB114955908525572199.html

Every silver-lined solar cell: http://www.materialstoday.com/view/6231/every-silverlined-solar-cell/

Samsung's SilverCare Washing Machine: http://www.treehugger.com/files/2006/01/every_dirty_loa.php