羟基硝酸锌对甲基橙的吸附性能研究

Study on the adsorption performance of hydroxyzinc nitrate to methyl orange

本文研究了采用直接沉淀法合成的羟基硝酸锌(ZHN)对甲基橙的吸附性能,分析了ZHN的吸附热力学、动力学行为,并探讨了吸附机理;同时还研究了溶液初始pH值和ZHN使用量对ZHN吸附效果的影响规律。结果表明:高温时ZHN的吸附热力学行为更符合Freundlich模型,低温时更符合Langmuir模型,其吸附动力学过程更符合准二级动力学方程;低温或低平衡浓度条件转变为高温或高平衡浓度条件时,吸附机理从表面吸附为主逐步过渡为以表面吸附和层间离子交换吸附共同作用方式为主;pH=7的中性溶液中ZHN对甲基橙的吸附率最高,ZHN使用量对吸附率和单位平衡吸附量影响规律呈相反趋势。

This paper studies the adsorption performance of Zinc Hydroxynitrate(ZHN)synthesized by the Direct Precipitation Method on methyl orange,analyzes the thermodynamics and kinetic behavior and the mechanism of ZHN adsorption,and discusses the influence of ZHN usage and initial pH value of the solution on the adsorption performance.The results show that the thermodynamic behavior of ZHN adsorption can be described as Freundlich model at high temperature and the Langmuir model at low temperature.,and the kinetic process conforms to the quasi-second-order kinetic equation;when the condition changes from low temperature or low equilibrium concentration to high temperature or high equilibrium concentration condition,the adsorption mechanism will be gradually adjusted from surface adsorption to the combined action of surface adsorption and interlayer ion exchange adsorption;the adsorption rate of ZHN to methyl orange is the highest in the neutral solution of pH=7,and the opposite trend is presented between the influence of ZHN usage on the adsorption rate and unit equilibrium adsorption capacity.