Study Of Nanometer Magnesia Preparation And Printing Wastewater Disposal

With China's rapid economic development, environmental issues, especially water pollution is a growing problem, while China is a country with the largest reserves of magnesium,so the use of nano-magnesium oxide sewage treatment have great possibilities.The full text is divided into six sections, namely the introduction, laboratory testi-ng methods, the preparation of nano-magnesium oxide powder, nano-magnesium oxide powder dye sewage treatment study of magnesium sintering of the initial pre-paration and pollution control research and conclusions And prospects.Using magnesium chloride and ammonia as raw material, the use of direct precipitation method can be prepared the best performance of nano-magnesium oxide powder, and the low cost of production in the process of environmental pollution problems. Specific process is as follows: deionized water dissolved magnesium chloride, TX-10 for dispersing agent, in conditions of constant temperature and stirring constantly, dropping ammonia, magnesium chloride control / ammonia (mole ratio) for a certain proportion, dropping completely, and then continuously stirred tank reactor for a period of time. Respond fully, it will be generated by magnesium hydroxide precipitation filter transferred to the vacuum filter funnel, during adding deionized water washing precipitation. No washing chloride ions to be. Precipitation will be washed, dried in the oven, the system can be a nano-magnesium oxide calcined powders.Preparation of the impact of magnesium oxide powder is affected by a lot of factors:⑴supersaturation, the nucleation rate soon. Growth rate decreased to a small grain size.⑵reaction temperature higher production of magnesium hydroxide precipitation greater, faster.⑶longer reaction time, a large quantity of precipitation, but the response time is too long will cause the re-growth of nanoparticles.⑷ammonia / magnesium chloride (mole ratio), the saturation increases to generate small size of magnesium hydroxide precipitation. Excessive ammonia chloride can guarantee adequate response to increased yield.⑸When surfactant addition of a low, the generation of magnesium hydroxide particles but not more than the surfactant particle size.⑹calcined system. Finally considered magnesium size, yield and activity, identified by the legal system of direct precipitation nano-magnesium oxide in the best conditions: temperature 55℃, MgCl2 concentration of 1.4 mol ? L-1, with reaction mol ratio 5:1, surfactant wt concentration of 0.20 percent, and the reaction time of 15 min, calcination temperature of 450℃, calcined for 3 h time. Using TEM and XRD detection, particle size products can be seen in the 50 to 60 nm, dispersion, and high purity. Because Nano-magnesium oxide powder has large specific surface area, surface energy, the organic dye adsorption sewage good governance role. Adsorption experiment are as follows:Preparation the red and yellow dye solution by adding the appropriate amount of Sodium Hexametaphosphate dispersing agent for the two solution of magnesium powder, mixing full after 24 h ;static filtering out sediment, and fully dry Add to muffle furnace burning, precipitation turning to white;Filter out the solution by spectrophotometer measured its concentration; preparation of the same Yellow dye solution, the two calcination precipitation grinding, joined counterparts color solution, mixing 24 h static. Repeat the above steps three times. See through the experimental data, magnesium powder dye adsorption on the good effect of the red dye adsorption rate of more than 80 per cent of the yellow dye adsorption rate of more than 90%, more importantly, the powder can be recovered repeatedly use adsorption and absorption performance and stability. After adsorption calcined powders after the XRD analysis, the results showed that the calcined powders purity still very high, the calcined powders can be removed by good adsorption of the dye. Even after the recovery of many of the significant decline powder adsorption still can be used in other areas, such as used for refractories, etc.With nano-magnesium, sodium silicate and starch as raw materials,I prepared sintered.Through dye adsorption experiments it shows that sintering red dye soluteion to a certain extent the effects of absorption, compared with the nano-powder, sinter has smaller proportion of the loss.In summary, this paper explore the preparation of nano-magnesium oxide powder optimal programme, and study the adsorption of the dye effects of powders, and explore new ways of sewage treatment.