Milli-Q_Advantage_A10_维护使用概要.ppt

* * * Carbon black is a generic term which applies to a wide variety of products ! There is the “Animal Charcoal” which is prepared by charring animals bones, meat and blood, and which is used in organic chemistry to adsorb impurities after a synthesis.This product is too rough to be used in water purification. Then there are natural activated carbons which are prepared from wood or coconut shell. On the left side of the screen, you can see a picture of this material taken with a microscope. This material is characterized by a large developed surface (1100 m2/gram) which allows it to capture large amounts of organic molecules by tertiary (Van der Waals) forces. It has two inconvenients which make it unsuitable for Type I water preparation : it binds low molecular weight organics slowly , and releases relatively large amounts of ions. However, those two characteristics are not a problem other applications such as the pretreatnment of feed water to RO cartridges : the purpose of activated carbon in this application is to bind chlorine, not organics, and there are already many ions in tap water , therefore adding some more won’t hurt. This is the reason why we use this activated carbon in the ROpak and Progard cartridges. Howver, to prepare ultrapure water, a higher quality material is required. * * This slide shows how, practically, a reverse osmosis cartridge is produced : around a central tube, 2 membranes are wrapped in a spiral form.The 2 RO membranes are attached on the side of the tube ; between the lines where they are bound are several holes allowing water to go inside the tube..The two RO membranes are separated by a mesh spacer (not shown on this slide). Feed water comes from the top, and flows between the 2 RO membranes ; part of the feed water goes through the membranes (the permeate) flows between them , along the RO membrane spacer, to finally reach the holes, and go inside the hollow tube. The rest of the water forms the reject. This system allows