Technologies

Clean Technology : Water purification

Clean Technology Portfolios

Technologies

Rechargeable Desalination Battery

UW–Madison researchers have designed a rechargeable desalination cell that can operate on seawater and is capable of performing a desalination/salination cycle with a net potential input as low as 0.2 volts. The cell comprises a sodium-storage electrode coupled to a chloride-storage electrode made of nanocrystalline bismuth foam.

The bismuth-based electrodes are able to store chloride ions in their bulk by oxidizing Bi to BiOCl in the presence of an oxygen source, such as water. Advantageously, BiOCl is insoluble in water over a wide pH range and inert against water oxidation. It also is stable over a wide range of anodic potentials. As a result, the new electrodes can be used for chloride removal in a variety of aqueous sources.

The BiOCl electrode can be converted back to a bismuth electrode by a reduction reaction, where the chloride ions are released into the electrolyte. This reverse reaction allows for the repeated use of the electrode for chloride storage/release via multiple chlorination/dechlorination cycles.
P170083US01

Hydrogels for Water Purification and More

UW–Madison researchers have developed modified hydrogels for treating contaminated water sources and other forward osmosis applications. Compared to conventional hydrogels they are able to swell and deswell far more rapidly and with greater amounts of liquid.

The new hydrogels are crosslinked mixtures of a superabsorbent agent and a stimuli-responsive agent such as poly(N-isopropylacrylamide) (PNIPAm). They are formed or ‘templated’ in the presence of a lyotropic liquid crystal (LLC) phase to endow them with special hydrodynamic properties.
P150302US02

Water Purification Membranes Bearing Antimicrobial Polymers

UW–Madison researchers and collaborators at Ben Gurion University in Israel have developed novel antibacterial water treatment membranes suitable for a wide range of water purification applications. The new entities are conventional membranes to which antimicrobial polymers have been attached. The antimicrobial agents are nylon-3 copolymers, which can be prepared via ring-opening polymerization of beta-lactams. Optimized nylon-3 copolymers display antimicrobial activity on par with natural antibiotic peptides. The polymers are immobilized on the surface of the membranes with chemically defined linkers.
P110224US02

Ultrafast Synthesis of Activated Carbon

Researchers at the University of Wisconsin System have developed an ultrafast method for the controlled production of various grades of activated and functionalized carbons. The proposed technology is a method to produce mesoporous carbon. The method is simple and can be rapidly carried out in large scale production with common reagents and processing equipment (heat source, acid and carbon source such as cellulose).
T130012US02

Ultrafast Synthesis of Activated Carbon

Researchers at the University of Wisconsin System have developed an ultrafast method for the controlled production of various grades of activated and functionalized carbons. The proposed technology is a method to produce mesoporous carbon. The method is simple and can be rapidly carried out in large scale production with common reagents and processing equipment (heat source, acid and carbon source such as cellulose).
T130012US02

Nanoporous Insulating Oxide Deionization Device for Softening and Treating Water

UW-Madison researchers have developed an improved deionization device capable of desalinating salt water, deionizing (softening) water and treating bacteria-contaminated water. This apparatus uses electrodes containing nanoporous insulating metal oxides rather than conventional carbon electrodes. The nanoporous insulating metal oxides provide superior capacitance, energy and power (see WARF reference number P06293US). The device contains two composite electrodes consisting of a conductive backing layer and a composite insulating oxide layer with an intermediate porous layer. These electrodes have the ability to remove hardening ions, salts and bacteria from residential and industrial water supplies more thoroughly than traditional methods.
P07104US

Photocatalytic Water Treatment Device

UW-Madison researchers have developed a water treatment cartridge that removes both inorganic and organic contaminants from water through the process of photocatalysis. Their device makes use of titanium dioxide, a ceramic material known to oxidize, and thus destroy, pathogenic microorganisms and complex organic molecules in the presence of ultraviolet light. UV-activated titanium dioxide also changes the valence state of inorganic molecules, such as heavy metals, facilitating their removal from water by other means. For example, titania ceramics oxidize arsenic (III), which is difficult to remove from water, to arsenic (V), which can be easily removed by adsorption.

The cylindrical water treatment device is composed of a stack of paired disks made of UV-transparent plastic. Each disk has a circular opening at its center like a washer, and carries a pattern of alternating concentric ribs and grooves on both faces. When the disks are fit together in pairs, the grooves and ribs form a series of concentric flow channels. Channel surfaces are coated with a thin layer of titanium dioxide, which is activated by a tubular UV light source inserted into the cartridge’s hollow center.
P06347US

Spectroscopic Detection of Water Contaminants Using Glow Discharges from Liquid Microelectrodes

UW-Madison researchers have developed a micro-fabricated, on-chip spectroscopic system for on-site, real-time analysis of trace contaminants in liquids and gases. The system works as follows: Two microfluidic channels transport sampled water from two large reservoirs into two smaller pools, or liquid electrodes. A micro-glow discharge generated between the liquid electrodes sputters water molecules and impurity atoms into the discharge region. The resulting discharge emits discrete wavelengths of light that correspond to specific atomic transitions. By analyzing a spectrum of these wavelengths, the chemical composition of the water can be determined.
P02042US