Climate change detection aided by membranes

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M e m b r a n e turns waste into power source Researchers at the Warwick Process Technology Group, part of the University of Warwick, UK, have devised a process that uses membranes to turn sewage and wet waste from paper mills into high purity hydrogen for fuel cells. Previous attempts to extract pure hydrogen from bio-matter to power fuel cells had met with limited success, even with dry material. The new process, in contrast, uses a plated membrane reactor to extract pure hydrogen from the more difficult, but exceedingly abundant wet bio-matter. In the first part of the process the waste biomass is gasified to break it down into methane, water, carbon monoxide, carbon dioxide (CO2) and a small amount of hydrogen. All these gases are then fed into a reactor, where a chemical reaction extracts the hydrogen from both the methane and the water. Under normal circumstances this reaction would reach an equilibrium and stop once a certain amount of hydrogen had been generated. However the reactor incorporates a palladium-coated ceramic semipermeable membrane, which only lets hydrogen pass through. This keeps the reaction going as long as it is being fed with the waste biomass because the hydrogen never builds up to the point where equilibrium is reached. Researchers have been able to harvest very pure hydrogen from the system (over 95% pure). The hydrogen produced by this energy efficient method can then be used to power hydrogen fuel cells. This process is also much cleaner

patents+technologies

than the traditional production methods of hydrogen, as it does not use fossil fuels, and therefore does not produce more CO 2 than is produced naturally from the material biodegrading, and no other emissions such as nitrous oxides (NOx). The research team led by Dr Ashok Bhattacharya are part of a European consortium that includes Dutch, German and UK companies. To date the research consortium has received @3.9 million (US$3.7 million) in funding to scale-up their laboratory system into larger prototypes. It is eventually anticipated that the research team's plated membrane reactors will be built as small industrial units located on-site at sewage plants or paper mills.

Cost effective charcoal filter recycling Pulsatron Technology Corp, based in California, USA, has designed a system that removes trapped contaminants such as hydrocarbons and mercaptans from saturated charcoal filters, restoring their filtration capabilities. The new system, called the Pulsatron filter recycling unit combines the electronic power of the company's existing pulse corona technology called Pulsatech ®, with a pressurized deabsorption system, to split harmful molecules back to their natural elements. The Pulsatech device has already proven effective against NOx, volatile organic compounds (VOCs) and odours from continuously flowing waste streams of burning processes. Based on extensive testing and a study on how various industries use

filters, Pulsatron anticpates that the filter recycling system could save companies using charcoal based filtration systems thousands of dollars. Most used charcoal filters are currently either incinerated or discarded.

Climate change detection aided by membranes According to Sterlitech Corp of Kent, Washington, USA, oceanographers are using its silver membranes to test for climatic changes in the open ocean.

Scientists are using the radioactive particle marker thorium-234 (234Th) to gain a better understanding of both the temporal and spatial variability of biological particle formation and sinking in the world's oceans. To measure total thorium concentrations 234Th is scavenged from a relatively small amount of sea water using manganese dioxide. The resulting precipitate is then filtered through a 1.2/~m silver membrane. The radioactivity from the particulate 234Th captured on the membrane is then measured. Silver membranes are said to be particularly suitable for thorium sampling bacause unlike either glass fibre or quartz filters, they do not possess any background radiation and do not absorb dissolved 2~4Th (or dissolved organic carbon or nitrogen). Also, silver membranes are relatively dense so they partially reflect the radioactivity, resulting in a higher counting efficiency Finally, particulate samples are stable on the membrane, so other elements of interest such as carbon, nitrogen or silica can be sampled after the 234Th analysis is completed.

Patent Summaries Plate-shaped Filter Element having Reinforced End Edges and a Method of Producing Same, MHB Filtration GmbH + Co. KG, Germany. WO 0 1 / 4 7 6 2 0 . Date of Publication: 05 July 2001. Filter for Polymer Melts, Union Carbide Chemicals & Plastics Technology Corp, USA. WO 0 1 / 4 7 6 8 7 . Date of Publication: 05 July 2001.

Seitz-Schenk Filtersystems GmbH, Germany. WO 0 1 / 4 7 6 1 6 . Date of Publication: 05 July 2001.

Cylindrical Filter and Method of Manufacturing the Filter, Chisso Corp, USA. WO 0 1 / 5 2 9 6 9 . Date of Publication: 26 July 2001. Impregnated Filter, Honeywell International Inc, USA.

Method and Device for Supplying Filtering Aids and/or Process Materials during Filtration,

Filtration+Separation

WO 0 1 / 5 4 7 9 6 . Date of Publication: 02 August 2001.

July/August 2002

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