改性普鲁兰复合吸附剂除氟中共存离子竞争性吸附研究

发布时间：2018-07-26 20:06

【摘要】：本文采用氯化铝作为辅助剂配合MgOP用于脱氟,以探讨其对溶液处理后的pH的调节作用。并对在铝盐存在时,MgOP的除氟行为进行了动力学和热力学的研究。结果表明:铝离子会在酸性环境和氟离子发生络合反应,生成稳定的络合物或沉淀,而在碱性环境下这种络合反应则会消失。由于吸附过程中,出水pH随时间而增加,因此在溶液由酸性变为碱性时,和铝离子络合的氟离子会发生解离反应,从而回到溶液中,使得溶液中的氟离子浓度略微有所增加。在氯化铝存在时,伪二阶动力学模型和粒子内扩散模型以及Langmuir吸附等温线模型能很好描述MgOP的除氟过程,且此过程为吸热反应。本文对同时含有氟离子和磷酸盐的双组分吸附系统进行了研究。结果表明:在初始氟离子和磷酸盐浓度为10mg/L时,MgOP固体浓度为2g/L时,氟离子和磷酸盐的去除率都达到90%以上且溶液的初始pH对其吸附结果无显著影响。在氟离子存在时,MgOP对磷酸盐的吸附平衡较单组分吸附系统中的会大大提前,但对吸附剂的吸附容量无显著影响;而在磷酸盐存在时,MgOP对氟离子的吸附速率会受到影响,但MgOP的吸附容量和吸附平衡未受到显著影响。几种典型形态磷酸盐对MgOP的除氟性能无显著影响,且MgOP对该形态下的磷酸盐也有较好的处理效果。在双组分系统中,MgOP的除氟过程符合伪二阶动力学模型和粒子内扩散模型以及Langmuir吸附等温线模型,且该过程为吸热反应。MgOP对氟离子和磷酸盐的最大吸附量分别为164.79mg/g和464.9mg/g。不同的离子加入顺序会影响MgOP处理双组分吸附系统的结果。总而言之,MgOP的吸附性能优秀,可以应用于同时含氟和含磷废水的处理,并且氯化铝能有效改善MgOP除氟后溶液出水pH较高的问题。同时实验结果表明在双组分吸附系统中当初始氟离子和磷酸盐浓度较低时,MgOP对二者的吸附量不会受到影响,但其吸附速率会改变。
[Abstract]:In this paper, aluminum chloride was used as auxiliary agent combined with MgOP for defluorination in order to study its effect on pH adjustment after solution treatment. The kinetics and thermodynamics of defluorination of MgOP in the presence of aluminum salt were studied. The results show that aluminum ions can react with fluorine ions in acidic environment to form stable complexes or precipitates, but this complex reaction will disappear in alkaline environment. As the pH of effluent increases with time during the adsorption process, when the solution changes from acidic to alkaline, the fluorine ion complexed with aluminum ion will undergo dissociation reaction, and then return to the solution, and the concentration of fluoride ion in the solution will increase slightly. In the presence of aluminum chloride, pseudo-second-order kinetic model, intraparticle diffusion model and Langmuir adsorption isotherm model can well describe the defluorination process of MgOP, which is an endothermic reaction. In this paper, a two-component adsorption system containing fluorine ion and phosphate has been studied. The results show that when the initial concentration of fluorine ion and phosphate is 10mg/L, the removal rate of fluoride ion and phosphate is more than 90%, and the initial pH of the solution has no significant effect on the adsorption results. In the presence of fluorine ions, the adsorption equilibrium of phosphate by MgOP is much earlier than that in single-component adsorption system, but it has no significant effect on the adsorption capacity of adsorbents, but the adsorption rate of fluorine ions is affected by MgOP in the presence of phosphate. However, the adsorption capacity and adsorption equilibrium of MgOP were not significantly affected. Several typical forms of phosphate had no significant effect on the defluorination performance of MgOP, and MgOP had a good effect on the treatment of phosphate in this form. In the two-component system, the defluorination process is in accordance with pseudo-second-order kinetic model, intraparticle diffusion model and Langmuir adsorption isotherm model, and the maximum adsorption capacity of fluorine ion and phosphate is 464.9 mg / g for 164.79mg/g and 464.9 mg / g for fluorine ion and phosphate in the process of endothermic reaction. The results of the two-component adsorption system treated by MgOP were affected by the addition order of ions. All in all, MgOP has excellent adsorption performance and can be used in the treatment of wastewater containing both fluorine and phosphorous, and aluminum chloride can effectively improve the high pH of effluent water after MgOP defluorination. At the same time, the experimental results show that the adsorption capacity of MgOP is not affected when the initial concentration of fluorine ion and phosphate is low, but the adsorption rate will change in the two-component adsorption system.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703

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