2013年11月8日星期五

4A molecular sieve

4A molecular sieve is an alkali metal aluminosilicate , can adsorb water , NH3, H2S, sulfur dioxide, carbon dioxide , C2H5OH, C2H6, C2H4 and other critical molecular diameter less than 4A . Widely used in gas and liquid drying , can also be used in certain gas or liquid purification and purification , such as argon gas from the system.
Molecular sieve is a kind of synthetic with micro groove cubic lattice sialic acid salts. According to the internal cavity of the crystal size and adsorption or reject molecules of different material, thus is called "molecular sieve". Molecular diameter less than the material can enter the molecular sieve of molecular sieve pores diameter crystal crystal, thus by adsorption, otherwise, the rejection. Molecular sieves are determined according to the different material molecular polarity of priority in the order of the adsorption.
According to the molecular adsorption effect on the choice of the size and shape of the different, namely only those smaller than the molecular sieve adsorption aperture molecules. For small polar molecules and unsaturated molecules, has selective adsorption performance, the larger the polarity, not the higher the degree of saturation, the choice and the stronger adsorption. Type A molecular sieve is A kind of molecular sieves which, its structure and NaCl are similar, belong to the cubic crystal system. Due to the 4 a molecular sieve effective aperture of 0.4 nm, so called 4 a molecular sieve, the space network structure by the silicon oxygen tetrahedron element [SiO4] and alumina tetrahedron unit [AlO4] staggered.
Application
1. Polyester additives agent: the role of 4 a zeolite as detergent additives mainly calcium ion exchange the water softening water, remove dirt and prevent dirt deposition. 4 a molecular sieve is most used in the generation of phosphorus to help lotion and apply the most sophisticated products. 4 a molecular sieve to replace sodium tripolyphosphate as detergent builder to solve the pollution of the environment has a major role. 4 a molecular sieves also can be used as a soap abrasive molding agent, toothpaste, etc.
2. Environmental protection, sewage treatment, 4 a molecular sieves can remove the NH3 - N in the sewage and Pb2 +, Cu2 +, Zn2 +, and Cd2 +, etc. Industry and agriculture, civil, and aquatic animal husbandry in the discharge of wastewater containing ammonia nitrogen, not only harm fish such as survival, pollution in aquaculture environment, and promote the growth of algae, and lead to the blocking of rivers and lakes. Due to the 4 a molecular sieve of NH4 + high commutativity choice, has been successfully applied in the field. From metal mining, smelting, metal surface treatment and effluent from chemical industry and other departments, containing heavy metal ion great harm to human body. Deal with the sewage with 4 a molecular sieves in addition to guarantee water quality qualified, can also recycle heavy metal.
3. The other purposes:
(1) water treatment - hard water softener, can replace the current widespread use of sulfonated coal in our country, thus reducing costs;
(2) the metallurgical industry - separating agent, separation, extraction from brine potassium, rubidium, cesium, etc. In industry for enrichment, separation and extraction process;
(3) the petrochemical industry, catalyst, desiccant, adsorbent;
(4) agriculture - soil conditioner;
(5) the medicine - silver zeolite antimicrobial agent.
About us
SILICA GEL supplier----Fenglong Chemical Co., Ltd. is primarily engaged in manufacturing silica gel since 2001. Our silica gel manufacturing plant is located in Maanshan with manufacturing capacity of more than 500-MT silica gel per year. We are manufacturing Indicating silica gel & Non-Indicating type of SILICA GEL in all grades such as blue silica gel, orange silica gel and basic silica gel such as type A silica gel , type B silica gel ,type C silica gel and another special silica gel Column chromatography silica gel . We are Chinese manufacturer of silica gel and supplying it across the world. Silica gel manufactured by us is of best quality which is widely used as cat litter, dessicant silica gel in anti-rusting and moisture-proof of product, packaging, drying and separation of gases, the catalyst carrier of petrochemical industry and so on.


Factors influencing the biochemical degradation of LAS

Factors influencing the biochemical degradation of LAS
Physical and Chemical Properties
Appearance under normal temperature as milky, liquid material; when it is warmed, it becomes transparent liquid. Soluble in water while insoluble in chloroform. Air bubbles would be generated when in water, which is of such functions as dispersing, decontamination and reducing surface tension, etc. It is easy to form stratified layer after long storage time while the chemical properties do not change, so it is better to use after thorough stirring.
The temperature
Microbial growth need to be in the right temperature, only in the appropriate temperature, the degradation rate of LAS was biggest. Optimum growth and microorganism decomposition temperature at 30 , and its activity in a certain temperature range varies with temperature
Increased. Studies have shown that at 20 , linear alkyl benzene sulfonate (LAS) degradation in the aquatic system speed is (1.5 ~ 3.5 ) 20 times. Chemical reaction rate is affected by temperature. So the temperature can affect LAS biochemical degradation.
PH
In general, the pH of water, microbial activity has a direct impact. Suitable pH range of different microorganisms. Degradation of LAS microorganisms such as bacteria, actinomyces, pH change will cause the change of cell charge, at the same time will affect the activity of enzyme in cells. However, for a river, the influence of pH value on the LAS is not very obvious.
The initial concentration of LAS
Pollutant itself to microbes, generally speaking, there are certain toxicity, and the toxicity increased with the increase of pollutants concentration increased. Studies show that when the concentration of LAS > 10 mg/L, the inhibition of its degradation is obvious. And studies have shown that LAS can affect aerobic degradation of organic matter in PH self-adjusting ability. When the initial concentration of LAS is greater than 20, then stop the aerobic degradation of organic matter in the PH of self-adjusting ability, reduce microbial activity.
Effect of dissolved oxygen
Most of the LAS aerobic degradation is mainly to increase the dissolved oxygen concentration , can significantly increase the degradation of LAS . Aerobic biodegradation of LAS mainly contains three kinds of mechanism: ( 1 ) by ω- oxidation of the terminal methyl group on the alkyl chain by oxidation of β or α- oxidation of long- chain molecules that form short -chain sulfonic disconnect benzene carboxylic acid ; ( 2 ) oxidation of the benzene ring to open crack action ; ( 3 ) de- substituted sulfonic acid salt removed by this process . However, these three mechanisms on the role of sequence researchers have not yet reached consensus view . Studies have shown LAS can be degraded under anaerobic conditions .
Other effects of coexisting substances
Biodegradation of LAS will be affected by the presence of other pollutants , when the water there are other biodegradable organic pollutants , will produce inhibition of microbial degradation of LAS or catalytic role in some of the water -binding makes the LAS chemically changed thus changing the biochemical degradation of LAS . LAS primary pollutants into the water after the other pollutants combine to form with a certain degree of dispersion of colloidal particles of industrial wastewater and domestic wastewater physicochemical and biochemical characteristics has a significant impact , and produce potentially dangerous.