保水剂吸释水分与养分动力学规律研究

Kinetics Law of Absorption and Release of Water and Nutrients by Super Absorbent Polymers

摘要:

围绕保水剂吸收、释放水分和养分的性质，通过室内试验深入分析了3种粒径规格（0.8~1.6mm、1.6~3.5mm、3.5~5.0mm）的保水剂在不同浓度（0.02、0.04、0.08mol/L）NH4H2PO4养分溶液中反复吸释水分及养分的动力学规律。结果表明：保水剂吸水初始，吸水速率达到最大，随后逐渐减小并趋于溶胀平衡，吸水倍率与溶液浓度关系由大到小依次为0.02、0.04、0.08mol/L，与粒径关系由大到小依次为1.6~3.5mm、3.5~5.0mm、0.8~1.6mm，随吸水次数增多而减小。保水剂吸持水分的能力和每小时释水量随转速（土壤吸力）的增大不断减小，释水时保水率与溶液浓度关系由大到小依次为0.02、0.04、0.08mol/L，与粒径关系由大到小依次为0.8~1.6mm、3.5~5.0mm、1.6~3.5mm，离心次数对其影响不显著。保水剂释水时滤液中NH+4N、PO3-4P浓度随转速（土壤吸力）增大整体呈减小趋势，累积释放量与溶液浓度关系由大到小依次为0.08、0.04、0.02mol/L，与粒径关系由大到小依次为1.6~3.5mm、3.5~5.0mm、0.8~1.6mm，随离心次数增多而减少。相较其他粒径保水剂,1.6~3.5mm粒径保水剂在同样条件下吸收、释放较多水的同时，还能释放出更多养分离子。

Abstract:

n agricultural production, the characteristics of water absorption and release of super absorbent polymers (SAP) are generally affected by soil solution and nutrient icons. The study on SAP of absorption and release of water and nutrients was mainly focused on through laboratory tests. These tests were used to investigate the kinetics of repeated absorption and release of water and nutrients in three particle sizes of SAP (0.8~1.6mm, 1.6~3.5mm and 3.5~5.0mm) at different NH4H2PO4 concentrations (0.02mol/L, 0.04mol/L and 0. 08mol/L). The results indicated that the water absorption rate of SAP reached the maximum value initially, and then decreased gradually and finally tended to reach the swelling equilibrium state. The water absorbency was decreased with the increase of solution concentration while water absorbency under different particle sizes of SAP ranked as follows:1.6~3.5mm, 3.5~5.0mm and 0.8~1.6mm. Meanwhile, the water absorbency was decreased with the 〖JP〗increase of water absorption times. The ability of SAP to absorb water and the amount of water released per hour were decreased with the increase of rotational speed (soil suction). The water retention rate was decreased with the increase of solution concentration when releasing water, while the water retention rate under different particle sizes of SAP ranked as follows: 0.8~1.6mm, 3.5~5.0mm and 1.6~3.5mm. However, the influence of centrifugation times on water retention rate was not significant. The concentrations of NH+4N and PO34P of the released solution were decreased with the increase of rotational speed (soil suction). The cumulative amounts of NH+4N and PO3-4P were increased with the increase of concentration of solution, while the cumulative amounts of NH+4N and PO3-4P under different particle sizes of SAP ranked as follows: 1.6~3.5mm, 3.5~5.0mm and 0.8~1.6mm. The cumulative amounts of NH+4N and PO3-4P were decreased with the increase of centrifugation times. It can be concluded that the amount of water absorbing, releasing and nutrient releasing at particle size of 1.6~3.5mm for SAP were much more than the other treatments.