摘要
通过静态吸附实验,研究了凹凸棒石黏土经改性后对水溶液中低浓度磷的吸附热力学特性,测定了288～318K范围内的吸附等温线。结果表明:改性凹凸棒石黏土对水溶液中低浓度磷的吸附符合Langmuir等温方程。根据热力学函数关系计算出吸附过程的焓变(△H)为47.65kJ/mol,吸附Gibbs自由能(△G)为–21.46～–30.46kJ/mol,表明改性凹凸棒石黏土对水溶液中低浓度磷的吸附是自发的吸热过程,是物理吸附和化学吸附并存的过程。吸附熵变(△S)为35.13J/(mol·K),表明该吸附过程是熵增过程。
Adsorption thermodynamics of low concentration phosphate onto modified palygorskites were investigated via static adsorption experiments.The adsorption isotherms in the range of 288 to 318 K were determined.The results show that the adsorption data of phosphate onto modified palygorskites follow the Langmuir isothermal equation.The variations of adsorption enthalpy,the Gibbs free energy and the entropy could be calculated according to the thermodynamic function.The change of adsorption enthalpy is 47.65 kJ/mol.The changes of adsorption Gibbs energy are in the range of-21.46 to-30.46 kJ/mol.The adsorption of phosphate onto modified palygorskites is spontaneous and endothermic,and the physical adsorption and chemical adsorption coexists.The change of adsorption entropy is 35.13 J/（mol·K）,showing that the adsorption is an entropy-increasing process.
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
2010年第9期1816-1819,1825,共5页
Journal of The Chinese Ceramic Society
基金
国家"863"科技攻关计划(2007AA06Z118)
安徽省科技厅重大专题(07020303062)资助项目
关键词
凹凸棒石
磷
富营养化
吸附
热力学
palygorskite
phosphate
eutrofication
adsorption
thermodynamic
