11-09 :: September 2011
nanotimes News in Brief
that can extract toxic lead and cadmium ions from industrial effluent, waste water streams or contami- nated groundwater.
To make the tobermorite, Coleman simply heats a mixture of ground cullet, lime (as a calcium source) and caustic soda (sodium hydroxide solution) to 100° Celsius (212° F) in a sealed Teflon container. Initial tests show that uptake of lead and cadmium from solution are rather slow, so Coleman suggests that, at this stage of development, the synthetic mineral might best be used in the in situ remedi- ation of groundwater rather than in industrial ex situ effluent filtration processes. The concept is now being extended to create other classes of ion exchange filter from unrecyclable and low-quality waste glass.
“The cullet-derived sorbent could be used in reac- tive barriers to prevent the lateral migration of pol- lutants in groundwater, rather than as a remediation material for waterways,” says Coleman. “Heavy metal-contaminated land and groundwater are global problems, arising from industrial and military activities and also from the natural leaching of hea- vy metal-bearing minerals,” she adds.
Nicola J. Coleman: 11 Å tobermorite ion exchanger from recycled container glass, In: International Journal of Environment and Waste Management (IJEWM), Vol. 8(2011), Issue 3/4, Pages 366-382, DOI:10.1504/IJE- WM.2011.042642:
http://dx.doi.org/10.1504/IJEWM.2011.042642
49
An international team of researchers has for the first time demonstrated that random, haphazardly grown silicon nanowires can significantly boost the power-producing capabilities of solar cells by trapping a broad spectrum of light waves and cap- turing sunlight streaming in from a wide variety of angles. The nanowires, which are wrapped in a shell of silicon oxide, serve as an antireflective coating on top of the usually shiny silicon wafer.
P. Pignalosa, H. Lee, L. Qiao, M. Tseng, and Y. Yi: Graded index and randomly oriented core-shell silicon nanowires for broadband and wide angle antireflection, In: AIP Advances, Volume 1(2011), Issue 3, September 2011, Article 032124 [6 pages], DOI:10.1063/1.3624838:
http://dx.doi.org/10.1063/1.3624838
Researchers from the University of Notre Dame in Indiana (USA) have harnessed another one of graphene’s remarkable properties to better control a relatively untamed portion of the electromagnetic spectrum: the terahertz band. Terahertz radiation offers tantalizing new opportunities in communi- cations, medical imaging, and chemical detection. Straddling the transition between the highest energy radio waves and the lowest energy infrared light, terahertz waves are notoriously difficult to produce, detect, and modulate. Modulation, or varying the height of the terahertz waves, is particularly impor- tant because a modulated signal can carry informa- tion and is more versatile for applications such as chemical and biological sensing. Some of today’s
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67