Novel superabsorbent membranes made of PVA and Ziziphus spina-christi cellulose for agricultural and horticultural applications
Abstract
Novel superabsorbent membranes consisting of polyvinyl alcohol (PVA), cellulose nanocrystals (CNCs) from Ziziphus spina-christi fibers (ZSP-fibers), glutaraldehyde (GLA) and glycerin (G) were prepared using a Hydraulic Lamination Hot Press machine. Crosslinking of PVA was used to improve the agricultural and horticultural applications. The plasticizer was used to increase the plasticity of the superabsorbent membranes. Ziziphus spina-christi fibers are a new source from which to isolate pure cellulose via mechanical and chemical treatment. These membranes were characterized using FTIR, XRD, SEM, TS and DSC. The superabsorbent membranes showed a greater equilibrium swelling capacity compared with the neat hydrogel. Moreover, the water transport mechanism of all the superabsorbent membranes was Fickian diffusion type. The influence of various factors, such as loading values (1, 3, 5, 7 or 10 wt% from CNCs), time, solution pH, saline solutions and the reswelling capability, on the swelling behavior of the superabsorbent membranes was also investigated. The superabsorbent membranes exhibited a good pH-dependent swelling reversibility and a high water retention capability, making them a more efficient water-saving material. The biodegradability of the superabsorbent membranes was evaluated under environmental changes. The superabsorbent membranes were also investigated for any antimicrobial activities against pathogenic bacteria like Candida albicans (fungus), Bacillus subtilis (G +ve), Staphylococcus aureus (G +ve), Proteus vulgaris (G −ve) and Erwinia carotovora (G −ve). The results showed that the design of innovative bioactive superabsorbent membranes is promising for agricultural and horticultural applications.