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以粉煤灰(fly ash,FA)为原料,通过酸改性和沉淀焙烧法制备的粉煤灰基复合材料(CeO_2/Fe_2O_3/FA)用于直接湖蓝5B(Direct sky blue 5B,DSB 5B)染料的吸附,考察了最佳吸附条件和吸附性能,探讨了吸附机理及复合吸附剂的再生。结果表明,水体pH、染料起始浓度、接触时间和振荡频率均对CeO_2/Fe_2O_3/FA吸附DSB 5B有影响;吸附30 min即可达到动态平衡,吸附量比FA增大近11倍。在不同温度和不同起始染料浓度下的吸附过程均能用准二级吸附速率方程精确描述。等温吸附数据符合Langmuir模型,所得饱和吸附量为263.16 mg·g~(-1),同时也较好地符合Dubinin-Radushkevich(D-R)模型,由此获得的平均吸附能(E)及由Arrhenius方程求得的表观活化能(Ea)值均表明吸附过程是由物理吸附、氢键作用和化学吸附共同控制,但化学吸附起主要作用。热力学参数ΔG°、ΔH°和ΔS°的结果表明复合材料对DSB 5B的吸附具有界面上混乱度增加的自发吸热性质。复合吸附剂能用很稀的NaOH溶液再生,且可至少重复使用3次。作为一种低值高效的新型吸附剂,CeO_2/Fe_2O_3/FA能用于高浓度染料废水中DSB 5B的有效去除。
Fly ash (FA) as raw material, fly ash-based composites (CeO 2 / Fe 2 O 3 / FA) prepared by acid modification and precipitation calcination were used in direct blue blue 5B (DSB 5B ) Dye adsorption, investigated the best adsorption conditions and adsorption properties, discussed the adsorption mechanism and the regeneration of the composite adsorbent. The results showed that water pH, initial dye concentration, contact time and oscillation frequency all affected the adsorption of CeO2 / Fe2O3 / FA on DSB5B. After adsorption for 30 min, the dynamic equilibrium could be reached, and the adsorption capacity increased by nearly 11 times than that of FA. The adsorption process at different temperatures and different initial dye concentrations can be accurately described by quasi-second-order adsorption rate equation. The isothermal adsorption data conformed to the Langmuir model, and the obtained saturated adsorption capacity was 263.16 mg · g -1, which was also in good agreement with the Dubinin-Radushkevich (DR) model. The average adsorption energy (E) The calculated apparent activation energy (Ea) values indicate that the adsorption process is controlled by physical adsorption, hydrogen bonding and chemisorption, but chemisorption plays a major role. The results of the thermodynamic parameters ΔG °, ΔH ° and ΔS ° show that the adsorption of the composite onto DSB 5B has spontaneous endothermic properties with increased chaos in the interface. The composite adsorbent can be regenerated with a very dilute NaOH solution and can be reused at least three times. CeO_2 / Fe_2O_3 / FA can be used as a low-value and efficient adsorbent for the efficient removal of DSB 5B from high-concentration dye wastewater.