凝胶型保水缓释氮肥形貌结构及盐分的影响

Morphology and structure of gel-based water-absorbent slow release nitrogen fertilizers and the influence of salt

采用环境扫描电镜和红外光谱观察和解析凝胶型保水缓释氮肥的形貌及物理结构和化学特征。结果表明,保水缓释氮肥干样品相结构是一个整体不均匀而局部较均匀的凝胶。保水缓释氮肥凝胶吸水膨胀体为透明的水凝胶,具有网络结构和孔隙,这是其存贮水分的物理空间。盐分影响或破坏保水缓释氮肥的物理和化学结构,破坏程度为氯化钠小于氯化钙,氯化钙对保水缓释氮肥网络物理结构的破坏用蒸馏水洗涤几乎不可逆转。因此,提高保水缓释氮肥的耐盐性是提高保水缓释氮肥吸水倍率的重要因素。

The water absorbing capacity of a gel is related to the basic characteristics of morphology, physical and chemical structure of the gel. The morphology and physical structure and chemical characteristics of a gel-based water-absorbent slow release nitrogen fertilizer （WASRNF） were investigated by environmental scanning electronic microscopy （ESEM） and infrared spectroscopy （IR）. The results indicated that the phase structure of solid WASRNF was heterogeneous in macro-scale and homogeneous in micro-scale. The swelled gel of WASRNF is transparent hydrogel with network structure and pores to store water. The salts influenced and destructed physical and chemical structure of WASRNF, the effects of sodium chloride on WASRNF hydrogel were less than that of calcium chloride, and the destructive effect of calcium chloride on physical structure of WASRNF could hardly be inversed by distilled water. Thus, it is important to increase WASRNF＇s tolerance to salts to increase its water absorbency.