Study on Water Absorption–Dehydration Characteristics for SAP Composite Soil for Rainwater Harvesting

• Main Authors: Youwei Qin, Tao Yang, Siyuan Wang, Fangling Hou, Pengfei Shi, Zhenya Li
• Format: Article
• Language: English
• Published: MDPI AG 2020-08-01
• Series: Water
• Subjects: superabsorbent polymer; composite soil; soil column test; repeated water absorption; average dehydration time
• Online Access: https://www.mdpi.com/2073-4441/12/9/2380

As a water absorption material, superabsorbent polymer (SAP) has gained its popularity in agriculture and environmental remediations. This study conducted a comparative investigation on saturated water content of cinnamon soil mixed with SAP. Two SAPs, SAP1 and SAP2, with different behaviors were tested, where SAP1 is an organic superabsorbent polymer, and SAP2 is polyacrylic acid sodium salt polymer. The saturated water content of SAP composite cinnamon soil was investigated with the weighing method. The repeated water absorption capacity and dehydration behavior of SAP composite soil under different designed rainfall intensity were investigated with a soil column tester. The results showed that (1) cinnamon soil mixed with SAP increased the saturated soil water content, and SAP1 was more effective than SAP2; (2) SAP held strong water absorption ability and recycling efficiency with eight repeated absorption–dehydration tests; (3) the average dehydration time for SAP composite soil were 626 h and 1214 h under 5-year and 10-year design rainfall intensities.