粉煤灰基沸石-TiO_(2)复合催化剂的合成及性能

Synthesis and properties of zeolite-TiO_(2) photocatalyst based on fly ash

粉煤灰作为一种固体废弃物,具有成本低廉、来源广泛等优点,可被广泛用于制备沸石的催化剂载体,实现其高值化利用的同时保护生态环境。以固体废弃物粉煤灰为原料制备了X型沸石-TiO_(2)复合光催化剂,在合成沸石的过程中成功负载TiO_(2),相较于合成沸石后再进行负载的方式,节约制备成本。采用4因素4水平正交试验,以TiO_(2)与粉煤灰的质量比、粉煤灰与氢氧化钠的质量比、粉煤灰与超纯水的质量比、晶化时间为影响因素,以亚甲基蓝去除率为目标函数探索了催化剂最佳制备条件,并对最佳催化剂进行了XRF、XRD、FTIR、SEM表征分析。试验结果表明,当m_(1)/m_(2)为1.0∶2.9、m_(3)/m_(2)为1.5∶1.0、灰水质量比为1∶10、晶化时间为24 h时(其中,m_(1)、m_(2)、m_(3)分别为TiO_(2)、粉煤灰和NaOH的质量),催化剂性能最佳。配制质量浓度为10 mg/L的亚甲基蓝模拟废液,添加该组条件下的催化剂0.25 g/L,30℃条件下反应1 h,在黑暗及紫外光照射条件下,亚甲基蓝去除率分别为42.47%和98.15%,说明该方法合成的X型沸石-TiO_(2)复合光催化剂对印染废水中的染料分子处理效果好,且粉煤灰属于火电厂废弃物,在低成本条件下制备了较理想的催化剂材料,实现以废制废。

Fly ash,as a kind of solid waste,has the advantages of low cost and wide sources,and can be widely used to prepare zeolite as catalyst carrier,realizing its high value utilization and protecting the ecological environment at the same time.The X-type zeolite-TiO_(2) composite photocatalyst was prepared from solid waste fly ash and TiO_(2) was successfully loaded during the synthesis of zeolite,which saved the preparation cost compared with the loading method after synthesizing zeolite.A 4-factor,4-level orthogonal test was used to explore the best preparation conditions of the catalyst with the mass ratio of titanium dioxide to fly ash,the mass ratio of fly ash to sodium hydroxide,the mass and volume ratio of fly ash to ultrapure water,and the crystallization time as the influencing factors,and the removal rate of methylene blue as the target function,and the best catalyst was characterized by XRF,XRD,FTIR,and SEM.The experimental results show that the best catalyst performance is achieved when m_(1)/m_(2) is 1.0∶2.9,m_(3)/m_(2) is 1.5∶1.0,the ash-water ratio is 1∶10,and the crystallization time is 24 h(where m_(1),m_(2),and m_(3) are the masses of TiO_(2),fly ash,and NaOH,respectively).The methylene blue simulated waste solution with a mass concentration of 10 mg/L is prepared,0.25 g/L of catalyst under this group of conditions is added,and the reaction is carried out at 30 ℃ for 1 h.The removal rates of methylene blue are 42.47% and 98.15% under the dark and UV irradiation conditions,respectively,indicating that the X-type zeolite-TiO_(2) composite photocatalyst synthesized by this method has a good treatment of dye molecules in printing and dyeing wastewater.Moreover,fly ash belongs to thermal power plant waste,and a more ideal catalyst material is prepared under low-cost conditions to realize waste to waste.