鼠李糖脂对堆肥介质中水分下渗和保持性能的影响

Effect of rhamnolipid on water permeation and reservation in compost matrix

为了探讨生物表面活性剂鼠李糖脂对堆肥介质中水分下渗和保持性能的影响,通过下渗实验模拟堆肥,测定了添加表面活性剂后的堆肥样品的含水率。实验结果表明鼠李糖脂保持水分能力优于SDS和Triton X-100,且添加鼠李糖脂浓度越高,介质水分保持性能越好。不同浓度的鼠李糖脂对水在介质中下渗过程的影响各异,400 RE mg/L的鼠李糖脂促进了水的下渗,且效果优于两种化学表面活性剂,而浓度高于800 RE mg/L的鼠李糖脂阻碍了水的下渗。不同深度段的颗粒介质中水分含量和鼠李糖脂含量变化存在对应关系,浓度为400 RE mg/L鼠李糖脂可以提高介质中水的承载能力,这可能是由于鼠李糖脂能够显著降低溶液的表面张力,有效增强溶液在颗粒介质表面的铺展和向微孔中的扩散所致,而高浓度的鼠李糖脂形成的聚集体堵塞了扩散孔道,反而阻碍了介质中水的下渗和减弱了介质对水的承载能力。

In order to explore the effect of biosurfactant rhamnolipid on water reservation and permeation in compost matrix, the permeation experiment was used for the simulation of compost and the moisture content of compost samples after surfactant addition was determined. The results show that rhamnolipid was superior to SDS and Triton X-100 in water bearing, and the higher the rhamolipid concentration added, the better the effect. The effect of rhamnolipid on water permeation in the matrix changed with the biosurfactant concentration. 400 RE mg/L rhanmolipid enhanced water permeation and the effect was better than that of the two synthetic surfactants. However, when the rhamnolipid concentration was higher than 800 RE mg/L it slowed down the water downflow. The water content was relevant to rhamnolipid content in the compost matrix of different depth sections. 400 RE mg/L rhamnolipid enhanced water bearing capacity in the matrix, which probably resulted from the ability of rhamnolipid to decrease water surface tension and to enhance water spreading on the granule surface and diffusion in micropores. However, rhamnolipid of high concentrations was readily to form large aggregates which blocked the micropores and weakened water permeation and bearing capability in the matrix.