Utilization Of Coal Fly Ash As Source For The Synthesis Of Ordered Mesoporous Sieves And The Study Of Heavy Metals And Phenolic Compounds Adsorption Performance

This paper was prepared to use coal fly ash as the main raw resource to synthesize mesoporous molecular sieves, and carried on the research about the heavy metal and phenolic compounds adsorption performance, which aroused wide concern due to the benefit of high efficiency, low cost and based on waste control by waste compared with other conventional adsorbents.This paper was to carry out a research from synthesis of mesoporous molecular sieves, materials quality characterization to heavy metal and toxic organism adsorption. The two parts were mainly discussed:one is the impact factors of the synthesis of SBA-15, MCM-41and MCM-48using coal fly ash, ensuring the quality from the structure and the performance; another is analysis of the adsorption mechanism of heavy metals and phenolic organic compounds thoroughly through dynamic research and the adsorption isotherm model. In this study we not only can get the new type adsorption material with high efficiency, wide sources and low cost, which can provide certain theoretical basis and technical support for deep treatment of industrial toxic organism and practical engineering application and have certain practical significance of relieving the environmental hazards, but also make the comprehensive utilization of the coal fly ash "Resources".First of all, using P123as template agent to synthesize SBA-15in strong acidic medium by alkali-hydrothermal synthesis method. The specific surface area is831m2/g and pore diameter is9.25nm. Modified SBA-15by grafting the amino group. Then, using NH2-SBA-15as adsorbent to adsorb Pb(II), adsorption process conforms to the secondary dynamics rate equation and chemical adsorption, adsorption isotherm model is more suitable to Langmuir model. As the temperature increases, the greatest adsorption capacity of Pb(II) is116mg·g-1at35℃Combine the silicon resource extracted from coal fly ash with CTAB as template agent in different reactant mole ratio of0.2CTAB:1SiO2and0.5CTAB:1SiO2in alkaline medium, synthesize ordered mesoporous molecular sieve MCM-41and MCM-48. The specific surface area of MCM-41is1000m2/g and pore diameter is3.18nm. Using MCM-41as adsorbent to process hydroquinone and p-chlorophenol deeply, the parameters such as initial adsorbent dosage, pH value and adsorption temperature can affect adsorption performance, the equilibrium adsorption data fitted to Langmuir isotherms. At35℃, the adsorption capacity of hydroquinone is263mg·g-1and p-chlorophenol is537mg·g-1. Due to the harsh reaction condition, ethanol must be added as activator, the specific surface area is1256m2/g and pore diameter is2.88nm. The characterization methods showed that all products have thermal stability and high degree of order.