Abstract
Superabsorbent integrated multiple functions, including absorbing water, preserving water and controlled releasing for fertilizer, which has attracted extensive attention in modern agriculture. In this study, a novel multifunctional superabsorbent of polyacrylic acid/humic acid/semicoke (PAA/HA/SC) with high water retention and favorable slow release performance was developed by incorporation of humic acid (HA) and oil shale semicoke (SC) via a simple free radical polymerization. The water retention, swelling kinetics, pH-dependent and swelling reversibility were investigated systematically. The water retention results showed that the prepared superabsorbent exhibited outstanding water-retention capacities of 824 g/g and 80 g/g in distilled water and 0.9 wt% NaCl solution respectively, as 15 wt% of HA and 6 wt% of SC were introduced into the three dimensional polymeric network of PAA. The slow release behaviors in distilled water and various salt solutions indicated that the release amount of HA was relatively fast in the initial stage, and then became flat after 16 days. Besides, the soil column leaching experiment revealed that the release amount of the HA reached the maximum value of 222.14 mg/L after 9 days, and potted experiment confirmed the growth-promoting effect for plant of PAA/HA/ SC. This work explored the practical application of SC in green and sustainable chemical engineering area, also provided an important reference for application of multifunctional superabsorbent in modern agriculture.

Keywords Plus：SLOW-RELEASESODIUM ALGINATEFERTILIZERHYDROGELPOLYMERGROWTHUREA

Published in EUROPEAN POLYMER JOURNAL，Volume 159；10.1016/j.eurpolymj.2021.110750，OCT 5 2021