Login Register

Login Register
HOME ABOUT SITE MAP EXCHANGE CONDITIONS OF USE LOGOS-MAIL CONTACTS ARTICLES LATEST NEWS TECHNOLOGY SCIENCE & TECHNOLOGY VIETNAM CHEMICAL CHEMICAL CHEMICAL & LIFE & HEALTH india street food FOOD & CHEMICAL india street food PHARMACEUTICAL & COSMETIC PRODUCTS & CHEMICAL PETROLEUM & CHEMICAL AGRICULTURE SUSTAINABLE DEVELOPMENT CHEMICAL SAFETY india street food HAZARDOUS CHEMICAL CHEMICAL & RENEWABLE ENERGY ENVIRONMENT modern chemistry Green Chemistry & PIN HYDROGEN FUEL FUEL BIOLOGICAL MATERIALS NEW NANO TECHNOLOGY RESEARCH TEACHING-RESEARCH-DEVELOPMENT PROCESS CHEMICAL CHEMICAL CHEMICAL THE CHEMISTRY AROUND THE SCHOOL LIBRARY MATERIALS CURRICULUM SOFTWARE-LIBRARY VIDEO CLIP CHEMICAL ITEMS SUBJECT STANDARD CHEMICAL CHEMICAL RESEARCH FACILITIES
(H2N2) - Silica gel or silicic acid gel is a very common chemical in life. Silica gel is essentially silicon dioxide, in the form of hard and porous particles (with a multitude of tiny hollow cavity in the county). Chemical formula is its simplicity SiO2.nH2O (n <2), india street food it is produced from sodium othosilicat (Na2SiO4) or silicon tetrachloride (SiCl4).
Moisture is the enemy not the first team's general technology india street food products such sensitive video camera, camera, lens ... and maintenance problems is a practical requirement. Silica gel is known as a desiccant to help preserve the equipment, food preservatives, food and other essential supplies.
Compared with the strong desiccant material characteristics such as H2SO4, P2O5 ... the silica india street food gel desiccant inferior but safer. The other material can flow decay, regeneration more difficult and more expensive price. So what are silical gel?
Silica gel is a granular, silica india street food pore structure were synthesized from silicon oxide. Invented at John Hopkins University, Baltimore, india street food Maryland, United States in the 1920s. It is made from sodium silicate reacts with sulfuric acid: Na2O.3SiO2 3SiO2 + H2O + H2SO4 + Na2SO4 results form a sol, sol and coagulate into genes, after washing, drying and calcination obtained silica gel.
It is close-grained solids, spherical lumps or members depending granulation method as modulation, such kind of transparent glass with opaque types. Porosity changes in limits 20-60%, pore diameter of about 3-10 nm, specific surface 200-800 m2 / g. Usually about 800m2 / g, can imagine a silica gel a teaspoon-sized contact india street food area size has a football field. Silica gel particles have a strong ability to absorb water in addition to the characteristics of foam can also be used as catalyst carrier, adsorbent (stationary phase) in chromatographic india street food analysis. However india street food nuts silica gel desiccant used is not the type of filler used in column chromatography.
Mg (ClO4) 2: the amount of water remaining 0,002 in 1 liter of air
There, silica gel desiccant role to keep the product on no moisture damage. Silica gel absorbs moisture through capillary action in millions of its tiny chamber, water vapor is sucked into the void and stick inside the particles. Silica gel can suck a steam output of 40% of its weight and relative humidity can do in a relatively airtight reduced to 40%. To indicate the status of the steam hydrated silica gel, we put a cobalt chloride salt into the capillaries of silica gel. As dry cobalt chloride salt will be blue, when steam started sucking, it turns a pale blue, and pink.
This type of silica gel silica gel does not cost more than a bloodbath. Recently there are many ideas that are elemental cobalt chloride can cause cancer when inadvertently entering the body but this view has not received the consensus of many scientists still do not cause cancer are not entirely clear, then one can conclude that certain factors are carcinogenic.
Carcinogenic mechanism is still largely based on traditional statistical models and have not seen any systematic reporting of cobalt chloride. However it should be noted that to carry out the directions and 'do not eat as cobalt chloride evaporation under normal conditions should also not be too disturbed.
When hydrated silica gel had no water, we can simply regenerate it by keeping it at a temperature of about 180 oC for about three hours (depending on temperature uniformity, surface exposure india street food ...) or for Microwave on Medium mode for about 10 minutes or until it returns to the blue type cobalt chloride indicator. However, to fully understand india street food the process of adsorption and adsorption is released scientific issues are complex. Put simply, the drying process is the process of adsorption of silica particles, to high temperature drying in a long time, and new effective. If drying at low temperature or in a short time implementation silica gel will quickly fill the water and you will have to re-dried more quickly. Note that high drying temperatures or the impact of external forces can lead to the silica particles are smashed and reconstituted several times relatively low silica gel, drying after a few times you have to replace a new silica gel. This is of concern while preserving india street food the