| In this paper, novel magnesium silicate gels were synthesized using sodiumsilicate and magnesium salts as raw materials and the optimum hydrothermalsynthesis conditions were assured. The samples were characterized by N2adsorption-desorption isotherms, X-ray diffractometer, FT-IR spectrometers andthermogravimetry. The adsorption behavior of magnesium silicate gels were studiedby adsorbing dyes （methylene blue, fuchsin basic and malachite green）, metal ions(Co2+and Zn2+). The effects of the functions of initial concentration of solution,adsorbent dosage, contact time and initial pH on the adsorption performance werestudied.From the physical characterization, the BET surface areas of the samplesprepared were744m2·g-1,708m2·g-1,635m2·g-1, the average pore radius were7.08nm,7.59nm,7.46nm, respectively. The thermal stability of magnesium silicategels is better than magnesium trisilicate. From the X-ray diffractometer, magnesiumsilicate gels is an identical patterns of poor crystalline nature.The adsorption behavior of magnesium silicate gels were studied by adsorbingdyes （methylene blue, fuchsin basic and malachite green）. Studies showed theadsorption courses were all fast processes; the adsorptions were followed thepseudo-second order model and could be described by Langmuir isotherm. At15,25,35and45℃,the saturated adsorption mount for methylene blue were1026.5,1044.68,1071.44and1145.76mg·g-1, the saturated adsorption mount for fuchsinbasic were1057.5,1060.68,1063.49,1204.57mg·g-1, the saturated adsorptionmount for malachite green were758.03,1044.68,1186.36,1583.86mg·g-1.Magnesium silicate gels still have good adsorption properties after regenerated byroasting.Among the radioactive effluents,60Co and58Co are dominant radionuclides, which may represent a significant environmental hazard. The study of adsorptionCo2+and Zn2+onto magnesium silicate gels showed that the adsorptions werefollowed the pseudo-second order model and could be described by Langmuirisotherm. At25,30,35and40℃, the saturated adsorption mount for Co2+were109.74,102.22,133.25and134.42mg·g-1; the saturated adsorption mount for Zn2+were18.4,22.55,24.67and24.7mg·g-1. Magnesium silicate gels still have goodadsorption properties after regenerated by desorption.The novel magnesium silicate gels synthesized using sodium silicate andmagnesium salts have large surface areas. So the novel material have goodadsorption performance to pollutants in water. In the first place, the novel materialcan provide a new way for magnesium salts from brine utilization; moreever, auseful and cheap sorbent for pollution treatment can be made. |
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