Energy & Green Tech

Hybrid membrane doubles the lifetime of rechargeable batteries

The energy density of traditional lithium-ion batteries is approaching a saturation point that cannot meet the demands of the future—for example in electric vehicles. Lithium metal batteries can provide double the energy ...

Energy & Green Tech

Green hydrogen: Transportation in the natural gas grid

Researchers at the Fraunhofer-Gesellschaft have developed a technology for the energy-efficient and economic separation of hydrogen from natural gas. This membrane technology makes it possible for the two substances to be ...

Engineering

Attachable skin monitors that wick the sweat away

A new preparation technique fabricates thin, silicone-based patches that rapidly wick water away from the skin. The technique could reduce the redness and itching caused by wearable biosensors that trap sweat beneath them. ...

Energy & Green Tech

Harnessing the sun to purify concentrated waste streams

Reverse osmosis is one of the most common methods for purifying saline water, but the process produces limited results. About 20% to 50% of the water that enters the system remains as a concentrated waste stream.

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Membrane

A membrane is a layer of material which serves as a selective barrier between two phases and remains impermeable to specific particles, molecules, or substances when exposed to the action of a driving force. Some components are allowed passage by the membrane into a permeate stream, whereas others are retained by it and accumulate in the retentate stream.

Membranes can be of various thickness, with homogeneous or heterogeneous structure. Membrane can also be classified according to their pore diameter. According to IUPAC, there are three different types of pore size classifications: microporous (dp < 2nm), mesoporous (2nm < dp < 50nm) and macroporous (dp > 50nm). Membranes can be neutral or charged, and particles transport can be active or passive. The latter can be facilitated by pressure, concentration, chemical or electrical gradients of the membrane process. Membranes can be generally classified into three groups: inorganic, polymeric or biological membranes. These three types of membranes differ significantly in their structure and functionality.

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