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鉴于天然硅藻土因理化构造缺陷而导致的吸附性能局限性和传统物化方法对硅藻土改性效果的有限性,为了显著改善硅藻土的吸附性能,采用聚羟基铝对硅藻土实施了柱撑改性.通过扫描电镜(SEM)、红外光谱(FTIR)、X射线衍射(XRD)分析了硅藻土柱撑前后理化特性的变化,并考察了柱撑前后硅藻土表面性能及其对Cu~(2+)、Zn~(2+)吸附特性的差异.结果表明,硅藻土最佳柱撑条件为n(OH-)/n(Al3+)=2.2、KCl浓度1.8 mol·L~(-1)、Al/土比10 mmol·g~(-1)、反应温度60℃、反应时间24 h、老化温度200℃、老化时间0.5 h.柱撑后,聚羟基铝被成功置入硅藻壳体内部,形成了有效柱体,增大了孔道间距,拓展了吸附反应界面,使微孔表面羟基数量增多,表面活性增强.柱撑前后硅藻土对Cu~(2+)、Zn~(2+)的等温吸附特性均符合Langmuir模型,吸附动力学特性均符合二级动力学模型.柱撑后硅藻土对Cu~(2+)、Zn~(2+)的吸附容量分别达到7.491 mg·g~(-1)、11.312mg·g~(-1),较柱撑前分别提高了32.9%、33.3%,硅藻土吸附性能得到了极大的改善.
In view of the limitations of natural diatomite due to physical and chemical structural defects caused by the limitations of adsorption properties and traditional physicochemical methods for the modification of diatomite limited, in order to significantly improve the adsorption performance of diatomite, polyaluminum aluminum for diatomite implemented The changes of pillars were analyzed by SEM, FTIR and XRD.The physical and chemical properties of diatomite before and after pillaring were investigated, The results showed that the optimal conditions for the adsorption of diatomite were n (OH -) / n (Al3 +) = 2.2 and KCl concentration was 1.8 mol·L ~ (-1), the ratio of Al / soil was 10 mmol · g -1, the reaction temperature was 60 ℃, the reaction time was 24 h, the aging temperature was 200 ℃ and the aging time was 0.5 h. The formation of effective column in the diatom shell increased the pore spacing and expanded the adsorption reaction interface, which increased the number of hydroxyl groups on the micropore surface and enhanced the surface activity. , And the isothermal adsorption characteristics of Zn 2+ conformed to the Langmuir model and the adsorption kinetics were in accordance with the second-order kinetic model. The adsorption of Cu 2+ and Zn 2+ by diatomite after column- The capacity of which reached 7.491 mg · g ~ (-1) and 11.312 mg · g ~ (-1) respectively, which increased by 32.9% and 33.3% respectively compared with those before the column. The adsorption capacity of diatomite was greatly improved.