[Preparation of Poly-hydroxy-aluminum Pillared Diatomite and Characteristics of Cu, Zn Adsorption on the Pillar in Aqueous Solutions].

As an alternative solution to the limitations in adsorption properties of natural diatomite caused by its physicochemical structure defects and modification effects to diatomite using conventional physical/chemical methods, the diatomite was pillared using poly-hydroxy-aluminum to improve its adsorption properties. The change in physicochemical characteristics of the diatomite before and after pillaring were analyzed by Scanning Electron Microscope (SEM), Fourier Transform Infrared (FTIR) and X-ray Diffraction (XRD). The difference in surface properties of diatomite and its adsorption characteristics of Cu, Zn before and after pillaring were analyzed at the same time.

[Differential Effect and Mechanism of in situ Immobilization of Cadmium Contamination in Soil Using Diatomite Produced from Different Areas].

In order to understand the difference of in situ immobilization effect and mechanism of Cd contamination in soil using diatomite produced from different areas, the test was conducted using diatomite produced from Yunnan Tengchong, Jilin Linjiang, Zhejiang Shengzhou and Henan Xinyang of China as modifiers to immobilize cadmium contamination in simulated soil. The results indicated that the diatomite from all the four producing areas could effectively immobilize available Cd in soil, decreasing the available Cd content in soil by 27.7%, 28.

[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).