Superabsorbent Hydrogel from Cassava Waste Pulp – Acrylamide – Acrylic Acid to Increase Water Holding Capacity in Sandy Soils

Abstract

Abstract In this investigation, a superabsorbent hydrogel was produced from cassava waste pulp (CWP) and acrylic acid (AA) – acrylamide (AAm) in a ratio of 2:1.5:1 (CWP:AA:AAm) by grafting and crosslinking methods. The grafting procedure is initiated with ammonium persulfate (APS) at a concentration of 1%. In this study, cross-linked structures were produced using several concentrations of methylene bisacrylamide (MBA) (0%, 0.5%, 1%, and 1.5%). The impact of MBA concentration on the properties of the superabsorbent hydrogel was observed. The parameters investigated in this study included the equilibrium degree of swelling (EDS), grafting degree, gel fraction, and swelling kinetics (comprising the swelling exponent, swelling constant, and diffusion coefficient). Following this, the hydrogels were sprinkled into sandy soil with the purpose of examining the effects of hydrogel incorporation on the soil’s water holding capacity. The sample with a concentration of 0.5% MBA yielded the highest EDS at 9178% (g/g), as determined by the results. The gel fraction value obtained for the sample was 81.04% (g/g) and the crosslink density of this sample was measured to be 2.78 × 1023 m-3, while the maximal water holding capacity was found to be 54.16%.