This purification technology offers a more environmentally friendly and economically competitive method for purifying drinking water supplies.
To create the colloidal polymer abstract, polysulfone is dissolved and precipitated in a mixed water bath, forming small, relatively uniform colloids. When this material is contacted with water containing low concentrations of humic acid (a natural organic constituent of many drinking water supplies) the humic acid is removed through adsorption on the colloidal phase. Colloidal polymer adsorbent has many advantages over the conventional method of activated carbon. Activated carbons must be disposed of or regenerated after their absorption capacity is exhausted. Regeneration is energy intensive and can cause secondary air and water pollution problems.
Disposal of activated carbon sludge also poses a secondary pollution problem. Colloidal polymer adsorbent does not require disposal, and the regeneration process is environmentally friendly. The humic material can be chemically desorbed and the polymer colloids reused.
Also, when compared with a common activated carbon used in the drinking water treatment field, Norit powder, the new polymer colloids demonstrate a larger adsorption capacity.
Benefits
In municipal water supplies, dissolved natural organic matter such as humic acid can give color, taste, and odor to water, and during treatment of the water supply, the natural organic matter can react with chemical disinfectants such as chlorine to produce known carcinogenicchlorinated-organic compounds like chloroform. Polymer colloids can be added directly to water supplies and allowed contact time in order to absorb natural organic compounds. The colloids have a large absorption capacity, and can easily and cheaply be regenerated through a simple chemical desorption step. The adsorbent need not be disposed and the regenerating solution is easily neutralized.
Polymer colloids are an economic and environmental solution to the problems associated with conventional purification methods.
The construction of nanoporous metal-organic frameworks (MOF) by copolymerization of organic molecules with metal ions has received widespread attention in recent...
The construction of nanoporous metal-organic frameworks (MOF) by copolymerization of organic molecules with metal ions has received widespread attention in recent years. These materials are thermally robust and, in many cases, have high porosity. However, recent experiments have shown that some MOFs are not stable when exposed to >4% water, limiting their usefulness.
Coordination bonding overcomes this limitation, requires mild conditions to create frameworks, and brings myriad choices of building blocks. Trifluoromethoxy group, which has been proved on most water repellent polymers and coating materials, reduces the water damage on MOF structures. A water resistant MOF, namely, ZnMOF3 is obtained through both solvothermal synthesis and microwave assisted solvothermal synthesis. It has a comparable vapor adsorbtion capacity with the commonly used MOFs, but does not adsorb moisture at 70 C.
In addition, exposing ZnMOF3 to boiling water vapor for one week does not result in any dramatic X-ray powder pattern change. ZnMOF3 is a potential adsorbent in many industrial applications such as air adsorption.
Researchers at the University of Illinois at Urbana-Champaign have developed a new technology capable of effectively detecting and quantifying metal ions in a...
Researchers at the University of Illinois at Urbana-Champaign have developed a new technology capable of effectively detecting and quantifying metal ions in a sample by color changes. Accurate, versatile, and inexpensive, this technology uses the catalytic DNA-directed assembly of gold nanoparticles and its associated color changes to determine the presence and concentration of a particular metal ion. The sensor works like a pH paper and yet can detect a diverse range of analytes.
This catalytic DNA (DNAzyme) based biosensor technology can be used to detect and quantify metal ions such as lead, based on a simple blue-to-red color change. This method combines the high sensitivity and selectivity of DNAzymes with the convenience of gold nanoparticle-based detection. The technology allows for semi-quantitative and quantitative detection of metal ions in both high and low concentrations. DNA has recently been found to catalyze a variety of chemical and biological reactions.
Catalytically active DNA are isolated through in vitro selection. The in vitro selection method can be customized to select DNAzymes that are active in the presence of any chosen substance (target analyte). Active DNAzymes can cleave another piece of DNA in the presence of the target analyte used in the in vitro selection. The piece of DNA being cleaved by DNAzymes can be used as a linker for DNA-tagged gold nanoparticles.
Gold nanoparticles aggregated by DNA linkers have a blue color. Once the DNA linkers are cleaved by DNAzymes, the formation of blue nanoparticle aggregates is inhibited, and a red color of separated gold nanoparticles results. The fraction of DNA linkers cleaved by DNAzymes in a certain time is governed by the concentration of the target analyte. Thus, from the color of the resulting nanoparticle aggregates, blue, purple or red, the concentration of the target analyte can be quantified.
This technology has been demonstrated for lead detection and quantification, and is generally applicable for detection of a wide range of other analytes. The detection limit of a lead sensor is already at or below the limit set by the federal agencies. A unique feature of the DNAzyme-nanoparticle sensor is that the dynamic range for detection can be varied easily by using an inactive variant of the DNAzyme. This feature is extremely important for practical application because the concentration of the target analytes is often unknown. Sensors with adjustable sensitivity range such as these are suitable for point-of-use application to detect chemical and biological terrorism agents.
Applications
Consumer Market: such as home-based toxic metal detection and quantification kits, including lead, mercury, arsenic and chromium, in a similar way that pH is monitored.
Environmental Monitoring: This technology can be applied for on-site real-time environmental monitoring of water resources and soil, etc.
Industrial Process Monitoring: This technology can be applied for on-site real-time monitoring of toxic metal ions in industrial process as well as in waste water management.
Medical Laboratory Diagnostics: for the analysis of both beneficial and toxic metal ions.
Developmental Biology and Clinical Toxicology: This technology can be used to monitor metal ion spatial distribution and transportation simultaneously.
Benefits
Selective: Catalytic DNA is stable, selective, and extremely sensitive; therefore there is little to no interference from other ions
Inexpensive and Simple To Use: Does not require expensive or complicated equipment, colorimetric detection will allow for use in private homes
Versatile: This technology can be developed to detect any metal ions, including Magnesium, Calcium, Manganese, Zinc, Cobalt, Copper, Lead, Mercury, Arsenic, Chromium and Cadmium, as well as other diverse analytes such as chemical and biological warfare agents.
Tunable: The sensitivity range can be tuned so that the sensors can detect and quantify a wide range of concentrations of the target analytes without false positive or false negative results.
Dr. Logan Liu from the University of Illinois at Urbana-Champaign has developed a continuous real-time sensor device capable of biomolecule measurement. The device has...
Dr. Logan Liu from the University of Illinois at Urbana-Champaign has developed a continuous real-time sensor device capable of biomolecule measurement. The device has smartphone integrated sensors and can test and measure the levels of contamination in surface and groundwater. LIFEDISC is more convenient and price efficient than the current available methods on the market. Additionally, LIFEDISC enables real-time, on site results, whereas conventional water testing requires lab work and can take weeks to analyze.
Dr. Xiao Su has created a system and method for the electrochemical remediation of mercury using semiconducting polymer electrodes. This system and method is directly...
Dr. Xiao Su has created a system and method for the electrochemical remediation of mercury using semiconducting polymer electrodes. This system and method is directly applicable to the remediation of mercury from water streams, such as wastewater streams, as well as to downstream chemical processes. The use of semi-conducting polymers highly increases the kinetics and efficiency of desorption, making this adsorption technology highly re-usable. When compared with current techniques this system and method does not require chemically intensive regeneration processes, this minimizes secondary pollution while achieving high ion-selectivity towards mercury even in very small amounts (ppb-range).
Researchers from the University of Illinois have developed a unique geometry of an electrodialysis system for enhanced efficiency of water purification. Electrodialysis...
Researchers from the University of Illinois have developed a unique geometry of an electrodialysis system for enhanced efficiency of water purification. Electrodialysis can be inefficient due to concentration polarization of the ion depleted zone. The unique geometry of this technology increases the flux of purified water by removing current limiting regime in electrodialysis system.
