Clean Technology : Remediation & waste reduction

Clean Technology Portfolios


Slippery Antifouling Surfaces with Health, Environmental and Consumer Applications

UW–Madison researchers have developed a new approach for fabricating and functionalizing SLIPS on objects of arbitrary shape, size and topology (e.g., inside a hollow tube, etc.). The new SLIPS have greater control over how fluids behave when they come in contact. For example, they can be designed with oil-free regions to immobilize fluid droplets and/or control how they slide across the surface.

The new SLIPS are antifouling to bacteria, fungi and mammalian cells, and may be used for the controlled release of antibiotics and to prevent thick liquids or dirt from building up on a surface. They are fabricated via the infusion of oils into reactive polymer multilayers.

Sustainable Process to Remediate Liquid Waste Streams

UW–Madison researchers have developed an environmentally sound and cost-effective system to remediate effluent streams containing organometallic/inorganometallic contaminants. Metals are recovered in the process and the treated water can be recycled for industrial applications.

The system includes units for electro-oxidation, electro-deposition and electro-adsorption. These units work sequentially to (1) break the strong chemical bonds in the waste stream, (2) recover the heavy metal ions and (3) remediate the organic/inorganic material.

A primary advantage of the new system is the redesigned electro-deposition unit, which houses a concentrating cathode and helps in the recovery of metals present even in very low concentrations in a reusable form.

Superabsorbent, Sustainable Aerogels

UW–Madison researchers have developed organic aerogels with excellent absorbent properties. They are made by combining a water soluble polymer and cellulose nanocrystals/nanofibers (CNFs) derived from biomass. The polymer, such as PVA (polyvinyl alcohol), is cross-linked to form a gel and then water is removed by freeze-drying. The surface of the aerogel is coated with an organosilane, making it highly water repellent and superoleophilic (‘oil loving’).

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).

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).

Biodegradable Poly(Vinyl Ester) Block Copolymers and Related Poly(Vinyl Alcohol) Surfactants

UW–Madison researchers have developed PVA-based amphiphiles in which both the hydrophilic and hydrophobic blocks are biodegradable. Through careful selection of vinyl esters polymerized into a block copolymer structure, they have shown that ester functionalities along the backbone may be selectively hydrolyzed to unmask a PVA-block in a hydrophilic-hydrophobic diblock copolymer.

Given the well-known ability of PVA to self-associate and form gels, the polymer surfactants micellize and modify the rheological properties of the solutions in which they are dissolved. The tunable solution rheology of these surfactant dispersions, coupled with their environmental degradability, suits the polymers to a wide range of uses.

They can be synthesized using reversible-addition fragmentation chain transfer (RAFT) polymerization, organobismuth-mediated living radical polymerization or cobalt-mediated radical polymerization.

Earthworm Extract Provides a Biological Means of Decontaminating Prion-Containing Surfaces

UW–Madison researchers have developed a method of using earthworm extract to degrade prion proteins and minimize or eliminate their infectivity.  The extract can be applied to a surface that may carry prion-infected material to decontaminate it.  It contains enzymes, collectively called lumbrokinase, that are capable of reducing prion infectivity by at least 75 percent.

Photoelectrocatalytic Oxidation Removal of Ammonia for Aquaculture Systems

UW-Madison researchers have developed a water recirculation device that removes nitrogenous waste using photoelectrocatalytic oxidation (PECO).  This device avoids the disadvantages of biofilters in recirculation systems to allow for increasingly efficient and cost effective aquaculture production.

A photocatalytic anode and cathode are combined to form an electrolytic cell.  The photoanode is illuminated with ultraviolet (UV) light to create a highly oxidative surface.  Ammonia that comes into contact with the photoanode is converted primarily into nitrogen gas.  The products can be controlled by applying a potential difference to the photoanode. 

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.

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.

Nanoscale Corona Discharge Electrode

This invention describes the use of nanotubes and other nano-objects as corona discharge electrodes. A metal wire or plate, or other conductive substrate can be coated with nanostructures, such as carbon nanotubes, to produce a robust discharge electrode with a small radius of curvature. These novel corona ion sources provide high ion concentration and high charging efficiency with minimal ozone production.

Protein-Polysaccharide Hybrid Hydrogels

A UW–Madison researcher has developed a biodegradable, hybrid protein-polysaccharide hydrogel capable of absorbing large volumes of water or other liquids, and retaining the liquid in its structure without dissolving. The hydrogel consists of two matrices: an acylated, cross-linked protein matrix and an anionic polysaccharide matrix. The matrices interpenetrate, resulting in a homogeneous hydrogel with superior saline absorption and retention characteristics as compared to hydrogels fabricated solely from protein matrices.

To form the hybrid hydrogel, the polysaccharide matrix can simply be trapped within the protein matrix, or the two matrices can be covalently cross-linked by bridging moieties. The biodegradable nature of this hybrid hydrogel overcomes problems with current, synthetic hydrogels, which are extremely slow to degrade and may be composed of toxic components.

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.

Cleavable, Water-Soluble Surfactants

UW-Madison researchers have developed a chemo-degradable surfactant with labile groups that is potentially useful in eliminating these problems, by allowing the destruction of emulsification properties upon addition of chemical reagent to the solution. Specifically, the researchers have designed and synthesized disulfide-containing surfactants capable of being oxidized by sodium hypochlorite (bleach) to form less surface-active compounds, leading to the disruption of emulsions. This method offers a simple and rapid way to change solution properties by transforming the surfactant structure using bleach, a common and inexpensive product.

Improved Optical Waveguide

UW–Madison researchers have developed a waveguide that propagates light in an attenuated total reflection (ATR) mode, i.e., it enables samples to be examined directly in the solid, liquid or gas state without further preparation. The device comprises a transparent internal reflection element (IRE) and a porous, particulate transition metal oxide coating on at least one surface of the IRE. This device potentially could be useful for the economical scale-up of photocatalytic reactors for commercial remediation applications.