[Application of classical isothermal adsorption models in heavy metal ions/ diatomite system and related problems].
In order to fully understand adsorption nature of Cu2+, Zn2+, Pb2+, Cd2+, Mn2+, Fe3+ onto natural diatomite, and to find problems of classical isothermal adsorption models' application in liquid/solid system, a series of isothermal adsorption tests were conducted. As results indicate, the most suitable isotherm models for describing adsorption of Pb2+, Cd2+, Cu2+, Zn2+, Mn2+, Fe3+ onto natural diatomite are Tenkin, Tenkin, Langmuir, Tenkin, Freundlich and Freundlich, respectively, the adsorption of each ion onto natural diatomite is mainly a physical process, and the adsorption reaction is favorable. It also can be found that, when using classical isothermal adsorption models to fit the experimental data in liquid/solid system, the equilibrium adsorption amount q(e) is not a single function of ion equilibrium concentration c(e), while is a function of two variables, namely c(e) and the adsorbent concentration W0, q(e) only depends on c(e)/W(0). Results also show that the classical isothermal adsorption models have a significant adsorbent effect, and their parameter values are unstable, the simulation values of parameter differ greatly from the measured values, which is unhelpful for practical use. The tests prove that four-adsorption-components model can be used for describing adsorption behavior of single ion in nature diatomite-liquid system, its parameters k and q(m) have constant values, which is favorable for practical quantitative calculation in a given system.
Institute of Environmental Science and Engineering Research, Central South University of Forestry and Technology, Changsha 410004, China. zhujian198312@163.com
Jian
J
Zhu
Institute of Processing Technologies of Materials, Central South University of Forestry and Technology, Changsha 410004, China.
Qing-Ding
QD
Wu
Institute of Environmental Science and Engineering Research, Central South University of Forestry and Technology, Changsha 410004, China.
Ping
P
Wang
Institute of Environmental Science and Engineering Research, Central South University of Forestry and Technology, Changsha 410004, China.
Ke-Lin
KL
Li
Institute of Environmental Science and Engineering Research, Central South University of Forestry and Technology, Changsha 410004, China.
Ming-Jing
MJ
Lei
Institute of Environmental Science and Engineering Research, Central South University of Forestry and Technology, Changsha 410004, China.
Wei-Li
WL
Zhang
D000327:Adsorption; D007692:Diatomaceous Earth / Q000737:chemistry*; D007477:Ions; D019216:Metals, Heavy / Q000737:chemistry*; D008956:Models, Chemical
D007477:Ions; D019216:Metals, Heavy; D007692:Diatomaceous Earth; C033787:diatomite