Research Of Soil Amelioration With Zeolites Synthesised From Natural Matetials

Zeolites are a kind of inorganic porous materials with specific channel structure, including natural and synthetic zeolites. In recent years, the new materials and novel methods emerge in endlessly, providing a great convenience for the wide application of zeolite. As a result, zeolites are widely used in the fields of restoring the weak or damaged eco-environment, small-scale agriculture and so on in addition to chemical materials and wastewater treatment. In this paper, the research content includes two parts:1) using oil shale ash as the raw material by alkali fusion hydrothermal method to synthesize the high crystallinity and single phase NaX zeolite, and discussed the effect of NaX zeolite applied to sandy soil on seeds emergence.2) using natural mineral diatomite as the material by hydrothermal method to synthesize the high crystallinity and pure phase mordenite zeolite, and discussed mordenite zeolite influences on inorganic nitrogen in the soil, seeds emergence and the plant growth. The main conclusions are as follows:(1) NaX zeolite has been synthesized from oil shale ash by hydrothermal method. The results show that the product is single phase, good crystallinity, multilayer lamellar microspheres with the size of 1 um. NaX zeolite has a good adsorption performance with BET surface area being 441.80 m2/g and pore volumn being 0.20 cm3/g. Water static saturated adsorption capacity of NaX zeolite is 25.8%. Binary crystalline phase diagram of zeolites were rendered through the investigation to the ration of synthesis system.(2) Mordenite has been synthesized using natural mineral diatomite. The synthesized samples present the typical structure of mordenite, good crystallinity, irregular morphology and individual columnar with the size of 5-10 um. BET surface area of mordenite is 441.80 m2/g, pore volumn is 0.19 cm3/g and has a good adsorption performance. Water static saturated adsorption capacity of mordenite zeolite is 17.6%.(3) Laboratory column experiments showed that an addition of mordenite to the soil can significantly reduce the loss of nitrogen fertilizer. Compared with the control, the amount of NH4+-N in leachate can reduce up to 63%, and the content of NH+/-N in soil can be 97%. It plays an obvious role in promoting seeds emergence when mordenite is added to sandy soil. When using 1%-3% mordenite zeolite, it is most suitable for alfalfa seed cultivation. When adding 3% mordenite zeolite, it is most optimum zeolite rate to allium mongolicum regel seeds cultivation. But adding 5% mordenite zeolite to soil, which will seriously restrain alfalfa and allium mongolicum regel seeds emerge. In the cultivation of lettuce experiments we found that, it is most conductive to the growth of the lettuce in which 3% zeolite was used, getting the thick green leaf color, the most leaf numbers, and fresh weight and dry weight can be up to a maximum, respectively 16.6% and 14.7% compare to the control. According to the phalaenopsis cultivation experiment, founding mordenite plays an obvious role in promoting phalaenopsis growth and flowering.(4) Because of the high content of sodium ions in NaX zeolite framework, it cannot be directly used to improve the sandy soil. When NaX zeolite is modified to be NH4-X, we found nothing positive ameliorative effect of NH4-X on seed emergence in sandy soil. Consequently whether the X type zeolite can be used as a seedling substrate still need further discussion.