Na Article – Brent Stewart – Applications

Health Sodium is the sixth most abundant element in The Earth’s crust, which contains 2,83% of sodium in all its forms. Sodium is, after chloride, the second most abundant element dissolved in seawater. The most important sodium salts found in nature are sodium chloride (halite or rock salt), sodium carbonate (trona or soda), sodium borate (borax), sodium nitrate and sodium sulfate. Sodium salts are found in seawater (1.05%), salty lakes, alkaline lakes and mineral spring water. The production of salt is around 200 million tonnes per year; this huge amount is mainly extracted from salt deposits by pumping water down bore holes to dissolve it and pumping up brine. The chemical element sodium symbol is: Na, atomic number: 11 and atomic weight 22,9898. It’s a soft metal, reactive and with a low melting point, with a relative density of 0,97 at 20C (68F). From the .mercial point of view, sodium is the most important of all the alkaline metals. There are a number of technologies to remove sodium from water including ion exchange (IX), distillation, EDI and reverse osmosis (RO). RO is the most economical solution for removing sodium, it essentially removes 99%+. Pure Aqua, Inc. specializes in RO technology, to see Pure Aqua’s standard line of packaged RO equipment. Boron Article: Brent Stewart – Applications Engineer Boron is not present in nature in elemental form. It is found .bined in borax, boric acid, kernite, ulexite, colemanite and borates. Vulcanic spring waters sometime contains boric acids. Borates are mined in US, Tibet, Chile and Turkey, with world production being about 2 million tonnes per year. Boron is a non metallic element and the only non-metal of the group 13 of the periodic table the elements. Boron is electron-deficient, possessing a vacant p-orbital. It has several forms, the most .mon of which is amorphous boron, a dark powder, unreactive to oxygen, water, acids and alkalis. It reacts with metals to form borides. Humans can be exposed to boron through fruit and vegetables, water, air and consumer products. we have a regular daily intake of about 2 mg and about 18 mg in out body in total. When humans consume large amounts of boron-containing food, the boron concentrations in their bodies may rise to levels that can cause health problems. Boron can infect the stomach, liver, kidneys and brains and can eventually lead to death. When exposure to small amounts of boron takes place irritation of the nose, throat or eyes may occur. It takes 5 g of borc acid to make a person ill and 20 grams or more to put its life in danger. The WHO standard is 0.5 ppm for maximum concentration of Boron in drinking water, the level was actually increased to reflect the difficulty in meeting the previous requirement of 0.3 ppm. While RO technology removes boron, the rejection is poor. Boron exists in water as an acid or ion depending on the pH; membranes reject ions much greater than non-ionic acids. Similarly, membranes reject multivalent ions much for effectively then monovalent ions. The polarity of water forms a sheath around the ion, creating a larger ion that is easier to reject by the membrane, the larger the charge, the larger the sheath and rejection. The selection of the proper membrane and pH control is important when designing seawater RO systems (SWRO). Where one pass does not meet the WHO spec., a second pass or ion exchange can be used to polish the water from the first pass. About the Author: 相关的主题文章: