Membranes nylon mesh

Figure 3 is a schematic representation of a typical CO electrode. A KCI/HCOJ containing electrolyte solution is trapped within a nylon mesh spacer layer whose pH is monitored by a contacting conventional glass pH electrode. A CO permeable membrane isolates the electrolyte layer from the analyte phase. Currently available... 

Thus, glucose oxidase can be randomly immobilised on the modified nylon mesh (I). The resultant enzyme membrane (II) when held tautly over a platinun anode disc provides a high performance, long life glucose electrode which can be housed in a Stelte cell adapted for flow injection analysis (4). 

Utilike the enzyme nylon meshes, the viscose acetate-catalase membrane became very brittle after a y-radiation dose of 1.2 Mr ad, a condition which often led to tearing when attempting to reassemble the electrode for recalibration (7). 

Enzymes have been attached to a nylon matrix (135-13 7), a pig intestine (138), the hydrophobic membrane of a gas-selective sensor (139), and controlled pore glass (140). Recent comparative studies of the coupling agents GA and benzoquinone support the preferential use of benzoquinone for binding GOD to nylon mesh (13 7), or to cellulose acetate membranes (141) with lysine (13 7). Both investigations report robust electrode behaviors with respect to prolonged exposure to glucose, while lifetimes of the membrane electrodes were ca. 3 months. 

This reaction produces p-nitrophenoxide which strongly absorbs 404 nm radiation. The sensor tip is constructed with alkaline phosphatase covalently immobilized on a nylon membrane. This membrane is positioned at the common end of a bifurcated fiber-optic bundle. One arm of this bundle is connected to the source optics and the other is connected to the detector optics. Incident radiation is transported from a 100 watt tungsten-halogen lamp source to the sensor tip. A fraction of this incident radiation is back scattered off the nylon mesh and a fraction of this back scattered radiation is collected by the fiber-optic bundle and directed to a 404.7 nm interference filter and then to a photomultiplier tube detector. 

The probe chamber was canpletely filled with couplant gel, retained by a nylon mesh membrane of 5 microns aperture and 37 microns thread diameter stretched across the chamber opening. The enclosed probe ceurrying shoe was pressed against the inside of the wetted membrane and traversed as required within the chamber. 

Figure 4.15 shows the cross section of the spiral wound module.24 The spiral construction starts with two sheets of membrane placed back to back with a nylon tricot mesh spacer material in between. This tricot spacer provides the permeate channel for the membranes. These sheets of membrane and spacer are glued on 3 sides so that the permeate can only exit the spacer on one side. This set of membranes and spacer is called a "leaf." Leaves are then placed together with a low density polypropelene mesh spacer to provide the feed/reject channel for the membranes. The thickness of the mesh feed spacer can be adjusted from 28 mils to 34 mils to accommodate higher solids influent water (thicker feed spacers are more forgiving with respect to fouling with suspended solids than thinner spacers—see Chapter 4.4.2.3). The entire collection of leaves and mesh feed spacers are then wrapped around a perforated permeate collection tube so that the open side of the leaf is toward the perforated permeate tube (see Figure 4.16). Note that an 8-inch diameter membrane module has about 16 leaves, and each leaf is about 50 inches in length.

The surface of the diffusion-limiting membrane is protected from mechanical damage during deployment by a mesh (8) of either stainless steel for organic analytes or nylon for inorganic analytes.This mesh is held in place during deployment by a removable PTFE ring (9). 

Sheldon and Sutcliffe (17) and Sheldon (16) used a Coulter Counter to examine the particle retention of nylon and stainless-steel meshes, Whatman glassfiber filters, and Nuclepore and Millipore membranes. With light particle loading and low vacuum (12-13 cm of mercury), the Millipore and glassfiber filters retained particles of much smaller diameter than the manufacturers stated pore size. The meshes and Nuclepore membranes showed 50% retention of particles (by number) at their manufacturers reported pore sizes. 

Figure 4.15 shows deconstructed spiral wound module. The spiral construction starts with two sheets of membrane placed back to back with a nylon tricot mesh spacer material in between. This tricot spacer provides the permeate channel for the membranes. These sheets of membrane and... 

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