Coal gangue-enhanced eco-friendly superabsorbent composite for agriculture application

Improvement of the soil water retention through suitable amendments is one of the methods for the growh of the crop. In this study, a novel degradable superabsorbent of cellulose-g-polyacrylic acid/coal gangue (CS-g-PAA/CG) was prepared by grafting polyacrylic acid (PAA) on cellulose (CS) and introducing the solid waste coal gangue (CG) as an inorganic component. The structure, morphology, and thermal stability of the superabsorbent composite were systemically examined by FTIR, SEM and TGA. Meanwhile, the water absorption capacities of CS-g-PAA/CG in dinfferent pH or various saline solutions as well as the reuseability and the water retention capacity in soil were also investigated. The results suggested that the CG–polymeric network interaction was achieved through the electrostatic interactions or the hydrogen bonds and CS-g-PAA/CG possessed the eximious water absorption capacity, which was 681 g/g in distilled water and 81 g/g in 0.9 wt.% NaCl solution, respectively . What’s more, the plant pot experiments verifed the CS-g-PAA/CG not only significantly improved the soil’s water retention efficiency, but also could be promoted the plants growht. Furthermore, CS-g-PAA/CG degraded by about 44.71% in 70 d . The study demonstrates the potential of using a low rate of CS-G-PAA/CG for improment of the soil water rentention with the advantage of offering a non-toxic and eco-friendly solution to mass utilization of industrial solid waste for agricultural application.