钾长石负载二氧化锰对Ni2+的吸附性能研究

Study on adsorption performance of K-feldspar loaded MnO2 for Ni2+

以钾长石为原料,在其表面负载二氧化锰以合成二氧化锰/钾长石复合吸附材料(MnO2/Kfs)。通过静态吸附实验考察了不同影响因素对Ni^2+吸附性能的影响,并对吸附过程中吸附等温特性、吸附动力学和吸附热力学进行了研究。结果表明,溶液初始pH、MnO2/Kfs添加量、吸附时间和温度的增加均有利于MnO2/Kfs对Ni^2+的吸附;在20mL初始质量浓度为100mg/L的Ni^2+溶液中,MnO2/Kfs添加量为0.20g、初始pH为6、298K下吸附10h时,MnO2/Kfs对Ni^2+的吸附率达到90.68%。吸附过程符合准二级动力学模型和Langmuir等温模型,表明MnO2/Kfs对Ni^2+的吸附是以化学吸附为主的单分子层吸附;温度为298、308、318K时,其理论最大吸附量分别为14.217、22.114、27.218mg/g。吸附热力学结果表明,吸附是一个自发吸热熵增的过程。MnO2/Kfs重复使用4次对Ni^2+仍有较高的吸附率,再生性能良好。

With K-feldspar as raw material,MnO2was loaded on the surface of K-feldspar to prepare the composite adsorption material of MnO2/Kfs.The influence of different factors on the adsorption performance of this composite material was studied by static adsorption test,and the adsorption isotherm properties,adsorption kinetics,and adsorption thermodynamic were also researched.Results showed that the increase of initial pH,MnO2/Kfs dosage,adsorption time and temperature were all benefit for the adsorption of MnO2/Kfs on Ni^2+.With the MnO2/Kfs dosage of 0.20 g,initial pH of 6,temperature of 298 K and adsorption time of 10 h,the adsorption rate of MnO2/Kfs on Ni^2+reached 90.68%in 20 m L Ni^2+solution with the initial mass concentration of 100 mg/L.The adsorption process fitted with the pseudo-second-order kinetics model and Langmuir adsorption isotherm model respectively.Above results indicated that the adsorption of MnO2/Kfs on Ni^2+belongs to monolayer chemisorptions.The theoretical maximum adsorption capacities of the MnO2/Kfs are 14.217,22.114,27.218 mg/g when the temperature are 298,308,318 K respectively.The adsorption thermodynamic results indicated that this adsorption process is a spontaneous,endothermic and entropy increasing process.After reused for 4 times,MnO2/Kfs still had high adsorption rate for Ni^2+and good regeneration performance.