海藻酸钠水凝胶对尿素的缓释效果研究

Slow-releasing effect of sodium alginate hydrogel on urea

为研究海藻酸钠(SA)水凝胶在肥料缓释方面的应用效果,采用紫外分光光度法,通过测定SA"包裹"尿素水凝胶不同静水浸泡时间的氮元素的质量分数,计算"包裹"尿素在水中的扩散速率。结果表明,SA水凝胶对尿素起到明显的缓释作用,与纯尿素相比,SA水凝胶"包裹"尿素扩散时间延长了约300倍;同时,凝胶具有良好的吸水保水能力,其平均含水量高达88.9%。作为一种环境友好型材料与肥料缓释载体,海藻酸钠水凝胶具有一定的应用前景。

To investigate the application of sodium alginate （SA） hydrogel in controlled-release fertilizer, the contents of nitrogen released from the SA ＂encapsulated＂ urea is monitored by UV spectrophotometry method through soaking the SA ＂encapsulated＂ urea in water for different time. The diffusion rates of ＂encapsulated＂ urea in water can also be calculated. The results show that the SA ＂encapsulated＂ urea exhibits excellent slow-releasing performance. Compared with pure urea,its diffusion time in water is increased by ca. 300 times. Interestingly, the SA hydrogel displays excellent absorbing and retaining capacity of water,/, e. ,as high as 88.9% of the water retention. It is promising for SA hydrogel to be used as a sort of environment-friendly material and matrix, and opens a new window in the application of controlled-release fertilizer.