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Technology Scouting: Water Purification

14,125 bytes added, 07:05, 12 September 2012
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=Universities/Institute=
==IIT Madras==
'''Graphene from Sugar and its Application in Water Purification'''
'''In Collaboration with: VIT Madras'''
 
This paper describes a green method for the synthesis of graphenic material from cane sugar, a common disaccharide. A suitable methodology was introduced to immobilize this material on sand without the need of any binder, resulting in a composite, referred to as graphene sand composite (GSC). Raman spectroscopy confirmed that the material is indeed graphenic in nature, having G and D bands at 1597 and 1338 cm–1, respectively. It effectively removes contaminants from water. Here, we use rhodamine 6G (R6G) as a model dye and chloropyrifos (CP) as a model pesticide to demonstrate this application. The spectroscopic and microscopic analyses coupled with adsorption experiments revealed that physical adsorption plays a dominant role in the adsorption process. Isotherm data in batch experiments show an adsorption capacity of 55 mg/g for R6G and 48 mg/g for CP, which are superior to that of activated carbon. The adsorbent can be easily regenerated using a suitable eluent. This quick and cost-effective technique for the into a commercial water filter with appropriate engineering.
 
Source: [http://pubs.acs.org/doi/abs/10.1021/am300889u?prevSearch=%2528%2522water%2Bpurification%2522%2B%252B%2B%2522nanotechnology%2522%2529%2Band%2B%255BCollectionKey%253A%2B%252210.1555%252Fcategory.358319320%2522%255D&searchHistoryKey= ACS]
 
 
'''Understanding the Degradation Pathway of the Pesticide, Chlorpyrifos by Noble Metal Nanoparticles'''
 
Application of nanoparticles (NPs) in environmental remediation such as water purification requires a detailed understanding of the mechanistic aspects of the interaction between the species involved. Here, an attempt was made to understand the chemistry of noble metal nanoparticle–pesticide interaction, as these nanosystems are being used extensively for water purification. Our model pesticide, chlorpyrifos (CP), belonging to the organophosphorothioate group, is shown to decompose to 3,5,6-trichloro-2-pyridinol (TCP) and diethyl thiophosphate at room temperature over Ag and Au NPs, in supported and unsupported forms. The degradation products were characterized by absorption spectroscopy and electrospray ionization mass spectrometry (ESI MS). These were further confirmed by ESI tandem mass spectrometry. The interaction of CP with NP surfaces was investigated using transmission electron microscopy, energy dispersive analysis of X-rays, Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). XPS reveals no change in the oxidation state of silver after the degradation of CP. It is proposed that the degradation of CP proceeds through the formation of AgNP–S surface complex, which is confirmed by Raman spectroscopy. In this complex, the P–O bond cleaves to yield a stable aromatic species, TCP. The rate of degradation of CP increases with increase of temperature and pH. Complete degradation of 10 mL of 2 ppm CP solution is achieved in 3 h using 100 mg of supported Ag@citrate NPs on neutral alumina at room temperature at a loading of 0.5 wt %. The effect of alumina and monolayer protection of NPs on the degradation of CP is also investigated. The rate of degradation of CP by Ag NPs is greater than that of Au NPs. The results have implications to the application of noble metal NPs for drinking water purification, as pesticide contamination is prevalent in many parts of the world. Study shows that supported Ag and Au NPs may be employed in sustainable environmental remediation, as they can be used at room temperature in aqueous solutions without the use of additional stimulus such as UV light.
 
Source: [http://pubs.acs.org/doi/abs/10.1021/la2050515?prevSearch=%2528%2522water%2Bpurification%2522%2B%252B%2B%2522nanotechnology%2522%2529%2Band%2B%255BCollectionKey%253A%2B%252210.1555%252Fcategory.358319320%2522%255D&searchHistoryKey= ACS]
 
 
 
==Department of Environmental Geosciences, University of Vienna==
'''Measuring and Modeling Adsorption of PAHs to Carbon Nanotubes Over a Six Order of Magnitude Wide Concentration Range'''
 
Understanding the interactions between organic contaminants and carbon nanomaterials is essential for evaluating the materials<nowiki>’</nowiki> potential environmental impact and their application as sorbent. Although a great deal of work has been published in the past years, data are still limited in terms of compounds, concentrations, and conditions investigated. We applied a passive sampling method employing polyoxymethylene (POM-SPE) to gain a better understanding of the interactions between polycyclic aromatic hydrocarbons (PAHs) and multiwalled carbon nanotubes (CNTs) over a 6 orders of magnitude wide concentration range. In the low-concentration range (pg-ng L–1), sorption of phenanthrene and pyrene was linear on a nonlogarithmic scale. Here, sorption could thus be described using a single sorption coefficient. Isotherm fits over the entire concentration range showed that (i) monolayer sorption models described the data very well, and (ii) the CNTs sorption capacity was directly related to their surface area. Sorption coefficients for 13 PAHs (11 of which have not been reported to date) were also measured at environmentally relevant low concentrations. No competition seemed to occur in the low-concentration range and sorption affinity was directly related to the solubility of the subcooled liquid of the compounds.
 
Source: [http://pubs.acs.org/doi/abs/10.1021/es2007726?prevSearch=%2528thilo%2Bhofmann%2529%2BNOT%2B%255Batype%253A%2Bad%255D%2BNOT%2B%255Batype%253A%2Bacs-toc%255D&searchHistoryKey ACS], [http://medienportal.univie.ac.at/presse/aktuelle-pressemeldungen/detailansicht/artikel/nanotechnology-for-water-filter/ Medienportal]
 
 
 
==National Nanotechnology Center, NANOTEC, Thailand==
'''"SOS water" mobile water purifier'''
 
Researchers at Thailand<nowiki>’</nowiki>s National Nanotechnology Center (NANOTEC) have build the first locally made prototype solar powered water purification unit "SOS water" which combined the use of antimicrobial nanocoating to ceramic filters. Compared to conventional ceramic filter, an antimicrobial nanocoating ceramic filter will increase an extra security by killing or incapacitating bacteria left in the water and preventing the growth of mold and algae in the body of the filter. The project was implemented as a result of the need to provide drinking water to communities affected by the 2011 mega flooding in Thailand.
 
The researchers adapted the antimicrobial nanocoating know-how for water filtration and assembled into in the production of mobile solar-operating system (SOS) water purification. The raw water goes through 6 filtration steps one of which is the antimicrobial nanocoating ceramic filtration unit. The quality of drinking water meets the 2010 guide standard of drinking water by Department of Health, Ministry of Public Health, Thailand. The SOS water system is capable of producing 200 liters of drinking water per hour and easily integrated into a pick-up, light truck, a trailer or a flat hull boat. The researchers have collaborated with the Thai Red Cross Society to do field testing of a prototype SOS water the result of which was outstanding. NANOTEC has donated the prototype SOS water to HRH Princess Maha Chakri Sirindhorn, Executive Vice President of the Thai Red Cross Society on June 28, 2012 for community relief effort.
 
Source: [http://www.nanotec.or.th/en/?p=3721 NANOTEC]
 
 
==LEITAT Technological Center, Spain==
'''Ceramic and Polymeric Membranes for Water Purification of Heavy Metals and Hazardous Organic Compounds'''
 
To develop a new generation of nanostructured Low-Fouling and Self-Cleaning Membranes for Water Purification possessing several key properties such as:
 
* catalytic degradation of pharmaceuticals and organics
* removal of heavy metals
* scavenging of precious metals and rare earths
Source: [http://nano4water.eu/fileadmin/template/pdfs/Thessaloniki/01_Cerampol_Faccini.pdf Nano4water]
 
===Fouling resistant ceramic honeycomb nanofilters for efficient water treatment===
'''Company/Institute:''' Fraunhofer Institute for Ceramic Technologies and Systems IKTS, Germany
 
Improve the efficiency of high performance water purification by ceramic membranes:
 
* strongly increase membrane area of ceramic NF membranes
* apply and test anti fouling layers to reduce fouling tendency
* develop process schemes for treatment of different waters
* Life cycle assessment, cost analysis, techno-economical evaluation
* Active participation of industrial partners: RKV (membrane manufacturer), VMW (end-user) and CYCLUS (OEM, end-user)
Source: [http://nano4water.eu/fileadmin/template/pdfs/Thessaloniki/02_CeraWater_Weyd.pdf Nano4water]
 
 
 
==Division of Materials Science, Lulea University of Technology, Sweden==
'''Nanoenabled membranes based on bio-materials for water purification'''
 
* Development of bio-based nano-enhanced membranes for water treatment, with special focus on fertilizers, pesticides, heavy metal ions and mictobial contaminants relevant in Europe
* Use biobased nanomaterials like cellulose nanofibers and cellulose or chitin nanocrystals isolated from industrial residues and side-streams
* Tailored interaction with contaminants and low/anti fouling by surface functionalization
* The membranes and filters, possible compostable after use (eg. with recovered fertilizers)
* Prototype of membrane modules and scale up plan
Source: [http://nano4water.eu/fileadmin/template/pdfs/Thessaloniki/05_NanoSelect_Mathew.pdf Nano4water]
 
 
 
==Harvard University, School of Engineering and Applied Sciences==
'''An Electrochemical Carbon Nanotube Filter for Water Treatment Applications'''
 
Carbon nanotubes (CNTs) have a number of unique physical chemical properties such as have high aspect ratios, high specific surface areas, mechanical strength, chemical stability, and are conducting or semiconducting. Thus, CNTs can be formed into mechanically-strong and electrically-conducting porous thin films or three-dimensional networks that have potential for many applications including water purification. Chad D. Vecitis of Harvard University designed and modified a filtration device to allow for in situ electrochemistry using a perforated stainless steel cathode and an electrochemically-active multi-walled carbon nanotube (MWNT) microfilter anode; 40 to 100 mm in height and pore diameter of 50 to 130 nm. The electrochemical carbon nanotube filter performance towards the removal and oxidation of aqueous dyes, anions, and microorganisms is evaluated. Electrochemical filtration at 2 V resulted in <nowiki>></nowiki>98% oxidation of influent dye and <nowiki>></nowiki>6-log removal and/or inactivation of influent bacteria and virus. Environmental applications of the electrochemical CNT filter are discussed.
 
Source: [http://environmental-technology.seas.harvard.edu/research Harvard University], [http://www.andrew.cmu.edu/org/nanotechnology-forum/Forum_8/Abstract/Abstract_Vecitis.pdf Carnegie Mellon]
 
 
 
==Penn Engineering, University of Pennsylvania==
'''High Speed Water Sterilization System for Developing Countries'''
 
HydraVita is a high-speed water sterilization system designed for use in developing countries. To our knowledge, this is the first sterilization system to implement a silver nanowire/carbon nanotube-coated cotton filter (AgNW/CNT filter). The device<nowiki>’</nowiki>s main capabilities are inactivating bacteria and reducing the turbidity levels of water. In order to accomplish these objectives, HydraVita incorporates two main components: a turbidity-mesh cartridge that eliminates organic impurities and a AgNW/CNT filter cartridge that kills bacteria. In order to power the filter, the system is equipped with two 12V rechargeable batteries and a solar panel. This allows HydraVita to be used in remote locations with no connection to the power grid. Furthermore, the system is designed for modularity so that it can be easily disassembled for cleaning and maintenance in the field. The input and output water reservoirs are outfitted with standard NPT valves that give operational flexibility to the user, as it can be directly connected to a hose, water tank, or piping system. HydraVita<nowiki>’</nowiki>s novelty stems from its high-speed functionality, low manufacturing cost, modularity, and ease of maintenance.
 
Source: [http://www.seas.upenn.edu/~rlodhiya/Documents/ESE FINAL POSTER.pdf Penn Engineering]
 
 
 
==Wright State University, United States==
'''Metal Nanoparticles on Hierarchical Carbon Structures: New Architecture for Robust Water Purifiers'''
 
A new architecture for robustand powerful water purification media has been investigated. It consists of carbon nanotubes (CNT) attached to porous microcellular substrates. This is similar to several elegant and multifunctional designs seen in nature where dendrites and capillaries are attached to larger organs increasing their surface area. For this application, palladium and silver nanoparticles are attached to these surfaces for catalytic and anti-microbial activities. Palladium is a powerful catalyst for several reactions. In this study, the kinetics of carbon tetrachloride removal form water using Pd-activated material has been measured, and found to be very high. Silver nanoparticles are useful as antimicrobial agents and as plasmonic sensors. The effectiveness of these structures to remove E-coli from water has been tested, and the rates compared to currently available nano-silver materials. Both nano-particles were seen to be strongly attached to the nanotubes which were in turn strongly attached to the substrate. Durability tests indicate that failure occurs by delamination of graphite inside the substrate, rather than removal of individual CNT or nanoparticles from CNT. This observation bodes well for future use of this architecture in robust and efficient water purification devices.
 
Source: [http://www.techconnectworld.com/World2012/wednesday.html TechConnect]
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