Superabsorbent Polymer with Excellent Water/Salt Absorbency and Water Retention, and Fast Swelling Properties for Preventing Soil Water Evaporation

In arid areas, the rapid evaporation of water leads to severe water shortage for plant growth. Superabsorbent polymers have the prospect of preventing water evaporation because of its excellent water absorbency. However, insufficient in salt resistance, water retention, and swelling rate limit its application. Herein, we fabricated Hydroxyethyl cellulose-g-(Acrylic acid-co-2-Acrylamido-2-methyl-1-propane sulfonic acid)/laterite (HEC-g-P (AA-co-AMPS)/laterite) with exceptional abovementioned performances by aqueous solution polymerization. Under optimal synthesis conditions, the water absorbency of the superabsorbent polymer were 1294 g/g, 177 g/g, and 119 g/g in distilled water, tap water, and 0.9 wt% NaCl solution, respectively. The water retention of the superabsorbent polymer was still as high as 97.7% after 16 h at 25 celcius, the water absorbency was up to 832 g/g after re-swelling for 5 times at 40 celcius, and the water absorption reached swelling equilibrium was only 5 min. We investigated the effect of the mount of swollen hydrogel on the water evaporation rate in soil, and the results showed that hydrogels were effective in inhibiting soil water evaporation. Our study provides a new horizon for the application of superabsorbent polymer.