Sugarcane bagasse cellulose-PAA micro-composite super-water absorbent for sandy soil amendment: Exploring a complete set of studies from one-pot electron beam processing to pot-testing

Abstract

Sugarcane bagasse cellulose-poly(acrylic acid) micro-composite super water absorbent (SAB) was prepared using micro-fibrous cellulose extracted from sugarcane bagasse (CSB). One pot and up-scalable processes using electron beam (EB) induced simultaneous free radical graft copolymerization and cross-linking were designed and optimized to produce an interpenetrating polymer network of CSB-PAA. The CSB was prepared in the presence of acrylic acid (AA) (CSB/AA) in two different systems, i.e., i) water and ii) aqueous NaOH/urea co-solvent. The effects of CSB (2.5 and 5.0 %w/v) and AA (10–50 %v/v) concentrations and EB absorbed doses (5–100 kGy) on gel fraction, swelling ratio, and water absorption kinetics of the obtained EB-induced CSB-PAA micro-composite hydrogel (eCSB-PAA) were studied. The eCSB-PAA prepared using CSB in aqueous NaOH/urea co-solvent showed a good swelling ratio up to a maximum value of ∼400 g/g and was assigned as eCSB-PAA microcomposite super-water absorbent (eSAB). Aiming at eSAB, the effects of material composition, pH, and particle sizes on the water absorption kinetics were observed. The water retention ability of eSAB mixed with sandy soil (SS) (SS/eSAB) was assessed in terms of water flow rate, moisture content, and available water capacity (AWC) in comparison with SS and cultivation soil (CS). The water diffusion determined from water content as a function of soil depth was also investigated. The performance of eSAB for SS amendment was carried out in pot-testing using baby corn as a model plant. The eSAB showed its potential to slow down the water flow rate and increase water retention in SS. The SS/eSAB promoted baby corn growth and improved the qualities of baby corn products. This work shows the potential of EB processing to produce eSAB from CSB with the assistance of PAA. The eSAB is a promising super-water absorbent composed of cellulosic biomass for amending SS and solving drought areas for farming.