ISSN 1000-3665 CN 11-2202/P

    复合吸湿凝胶制备优化及其在干旱-半干旱地区的生态修复应用

    Optimization of composite atmospheric hygroscopic gel preparation and its application in ecological restoration in arid-semi-arid regions

    • 摘要: 水资源匮乏是限制干旱-半干旱地区生态修复效果的主要原因,吸附式空气取水技术在解决生态修复植物需水问题方面展现出极大潜力,但目前该领域应用研究相对较少。通过将异丙基丙烯酰胺(N-isopropylacrylamide,NIPAM)和丙烯酰胺(acrylamide,AM)共聚合成新型复合凝胶并负载吸湿盐,测试凝胶配比对其吸水与释水性能的影响以及在不同温湿度和光照条件下的性能及野外产水表现。结果表明:当NIPAM∶AM质量比为1∶1.5时复合凝胶的吸附与释水性能达到平衡,综合产水量最高,溶胀率达到24.7 g/g的同时可实现75.3%的释水,比聚-异丙基丙烯酰胺凝胶的产水量增加了31.3%;在温度20 °C,相对湿度50%条件下,复合凝胶负载的吸湿盐CaCl2∶LiCl摩尔比为1∶7时,吸湿量最高,为负载纯LiCl凝胶的1.14倍,且在相对湿度30%~100%条件下均可吸湿。将以上优化后的复合吸湿凝胶应用于干旱-半干旱地区矿山生态修复工程中,夏季日均产水量约为0.74 g/g,当用量在14.1~17.6 g时可弥补基于彭曼公式计算的植物生态需水量缺口,验证了应用的可行性。

       

      Abstract: Scarcity of water resources in arid and semi-arid regions is the main reason limiting the effect of local ecological restoration, and adsorptive airborne water extraction technology has shown great potential in solving the problem of water demand of plants in ecological restoration, but fewer studies have been conducted on the application of this technology in this field at present. Therefore, in this study, NIPAM and AM were co-polymerized to form a new composite gel and loaded with hygroscopic salts to test the effects of gel ratios on the water absorption and release properties, as well as the performance under different temperature, humidity and light conditions, and water production in the field. The results showed that the composite gel with NIPAM∶AM mass ratio of 1∶1.5 had the optimal balance between water adsorption and water release, and the dissolution rate reached 24.7 g/g while 75.3% of water release could be realized, which was 31.3% more than the water production of the PNIPAM gel. Under the condition of temperature 20 °C and relative humidity (RH) 50%, the composite gel loaded with hygroscopic salt CaCl2∶LiCl molar ratio of 1∶7 has the highest hygroscopicity, which is 1.14 times of that of the loaded pure LiCl gel, and can be hygroscopic under the condition of 30%−100% RH. The above optimized composite hygroscopic gel was applied to the ecological restoration project of mines in arid-semi-arid areas, and the average daily water yield in summer was about 0.74 g/g, which could make up for the shortfall of the ecological water demand of plants based on Penman's formula when the dosage was in the range of 14.1~17.6 g, which verified the feasibility of the application.

       

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