Preparation And Application Of Molecular Sieve From Fly Ash

The adsorption,ion exchange and catalytic properties of molecular sieve made it widely used in air separation,radioactive material cleaning and water purification treatment.Fly ash from different sources?FA1,FA2 and FA3?has different physical and chemical properties?different morphology,silicon-aluminum ratio,etc.?,and the properties and types of the prepared molecular sieves are also different.The specific surface areas of the molecular sieves prepared by FA1,FA2 and FA3 are 173 m²/g,132 m²/g and 113 m²/g,respectively.Moreover,the pore size distribution of molecular sieves prepared from FA1 fly ash is more concentrated,with an average pore diameter of 4.6 nm and an average pore volume of 0.63 m L/g.The molecular sieve loaded TiO₂ composite material has a photocatalytic 20 mg/L methylene blue sub-solution?MB?efficiency of 80%.Because the magnetic iron oxide in fly ash inhibits crystallization during the synthesis of molecular sieve and has a photocatalytic effect on TiO₂;non-magnetic iron oxide has almost no effect on the crystallization of molecular sieve and is beneficial to TiO₂ photocatalysis.Therefore,fly ash is different Pretreatment methods?untreated,magnetic separation,magnetic separation and pickling?have an effect on the performance of molecular sieves.The specific surface area of the molecular sieve prepared by fly ash after magnetic separation can reach 341 m²/g,and the MB photocatalytic efficiency of the composite material at 30 mg/L can reach 78%.Na X-type molecular sieve is prepared by using alkali-melt hydrothermal method with fly ash as the raw material.When the ash-alkali ratio?mass ratio of fly ash:Na OH:Na2CO3?is 1:1.5:0.3,the alkali melting temperature is 500?.When the crystallization time is 24 h and the crystallization temperature is 70?,the specific surface area of the synthesized molecular sieve can reach 448 m²/g,and the photocatalytic efficiency of MB at 40 mg/L can reach 80%.Using fly ash as a raw material,adding sodium silicate nonahydrate to increase the silicon content,and at the same time,seed crystals prepared at a ratio of SiO₂:Al₂O₃:Na2O:H2O to 7:1:6:300,and Na Y molecular sieve is prepared by the alkali fusion hydrothermal method,When the ash-alkali ratio?mass ratio of fly ash: Na OH: Na2CO3?is 1:1.5:0.3,when the seed amount is 10 m L,the crystallization time is 24 h,and the crystallization temperature is 90? The molecular sieve has a specific surface area of 507 m²/g and a photocatalytic MB efficiency of 40 mg/L of 85%.Figure 61;Table 15;Reference 65...