Preparation Of 18-crown-6/MM,T And Its Potential Ecotoxicity Research

With the rapid development of industry, it brings not only material wealth, but also environmental disruption, particularly heavy metal pollution problems. It is urgent for researchers to deal with heavy metal pollution. The inorganic adsorption materials had been developed rapidly during the past decades. It became a wide method for researchers to improve the adsorption properties of the material by the means of modification.Montmorillonite(MMT) is abundant, inexpensive, and has good physical and chemical properties(eg. high specific surface area, good absorption properties, etc.). So it had been paid wide attention to prepare a range of modified Na+-MMT through different methods(intercalation, silylation, etc.). In this paper, we have prepared the 18-crown-6 modified Na+-MMT and studied the adsorption of copper ions by modified Na+-MMT under different conditions(eg. ionic strength, p H, etc.). Besides, when the modified Na+-MMT as an adsorbent material was used in the environment, it might release chemicals(18-crown-6)into the surroundings, resulting in secondary pollution. Therefore, it is important to assess the ecological risk of 18-crown-6.(1) 18-crown-6/MMT was characterized as following: XRD results showed that, in contrast to MMT, 18-crown-6/MMT interval-distance became larger. TGA results showed that 18-crown-6/MMT had a significant weight loss at 396℃, which indicated that18-crown-6 intercalated into MMT successfully. The results of infrared analysis showed that 18-crown-6/MMT had a new peak at 2922 cm-1compared to MMT, which was assigned to hydrocarbon(C-H) stretching peak and indicated that MMT was modified by18-crown-6successfully.(2) The removal of copper ion by modified Na+-MMT was investigated and the results are as follows: the results of adsorption kinetics and thermodynamics showed that the adsorption of copper ion on the modified Na+-MMT fit well with the pseudo-second order kinetic equation(correlation coefficient R2=0.9994) and Langmuir isotherm equation(correlation coefficient R2=0.9900). The adsorption of copper can reach equilibrium within 60 minutes. With the decrease of p H, the adsorption amount falled. The increase of ionic strength might reduce the adsorption amount of copper ions. The impact study of co-existing ions on the absorption of copper ions showed that lead ions(Pb2+) had a stronger significant inhibitory effect on the absorption of copper ions(Cu2+) compared to zinc ions(Zn2+).(3) Mortality, avoidance, burrowing behavior and respiration of the earthworm Eisenia fetida were investigated in artificial soil contaminated with 18-crown-6 based on OECD standard method. The data showed that 48-h EC50 of 18-crown-6 to the earthworm was 120 mg kg-1soil and the 7-d LC50 was 584 mg kg-1soil.(4) In the earthworm bio-filter system, the expression level of heat shock protein 70 in earthworm increased significantly when 18-crown-6 was added into the sewage. It suggests that heat shock protein 70 is available as an effective and sensitive bio-indicator.