Utilization Of Rice Husk Ash As Silica Source For The Synthesis Of Ordered Mesoporous Silicas And Their Application Of Adsorption

Rice husk is a by-product after processing, produced a tremendous waste of rice husk ash without treatment, has caused great environmental pollution. Considerable attentions have been paid to adsorption technologies as efficient and versatile methods for water treatment. However, most of normal adsorbents have a low adsorption capacity. Therefore, based on the hot issue of water adsorption treatment, ordered mesoporous silica materials were synthesized using rice husk ash as the silica source, RHMCM-41and SBA-15were synthesized by hydrothermal method, silylanization MCM-41and SBA-15were synthesized by cocondensation method, which used as adsorbents for water treatment. The adsorption behavior and mechanism were investigated in detail. The results showed that:Characterization results indicated that both RHMCM-41and CH3-MCM-41possess an ordered2D hexagonal mesoporous structure. CH3-MCM-41possesses high specific surface (613m2/g), pore diameter (3.41nm), pore wall thickness (1.54nm) slightly increased. Adsorption of2,4-DNT onto CH3-MCM-41was investigated systematically using batch experiments. Results indicated that2,4-DNT can be effectively removed by CH3-MCM-41than RHMCM-41at neutral condition (pH=6.82). The adsorption mechanism is primarily brought about by hydrophobic interaction between2,4-DNT and CH3-MCM-41surface, then form an electron donor-acceptor complex between electron donor functions at the siloxane surface and the aromatic ring system of the2,4-DNT may be postulated as a plausible mechanism of interaction.Characterization results indicated that SBA-15and CH3-SBA-15possess an ordered2D hexagonal mesoporous structure. The high specific surface (473m2/g) and pore diameter (4.38nm) have a slight decrease, pore wall thickness (6.98nm) slightly increased. With the software Origin, isotherms of adsorption process were studied by linear method and non-linear method. The results showed different forms of equation would effect r2and X2significantly and impact the final determination where nonlinear method would be a method of avoiding such errors. Redlich-Peterson isotherm was most suitable for the data followed by Freundlich and then Langmuir isotherm by the non-linear method. The maximum adsorption capacities of Methylene Blue onto CH3-SBA-15was263mg/g, which larger than much of adsorbent materials from literatures.