Chitosan-Graft-Poly(acrylic acid) Superabsorbent’s Water Holding in Sandy Soils and Its Application in Agriculture

Abstract

Sandy soil has a low ability to absorb and store low water, low nutrient content, and a high water evaporation rate, so it is not suitable to be used as agricultural land. Superabsorbents can be used to overcome these weaknesses. The purpose of this study was to measure the abilities of the superabsorbents, including water holding, swelling, and water retention of sandy soil enriched with superabsorbent, and to analyze the chitosan-graft-poly(acrylic acid) superabsorbent characteristics. The superabsorbent was prepared by mixing a chitosan solution with ammonium persulfate as an initiator and acrylic acid, which had been neutralized with KOH. Then, the mixture was cross-linked with N,N′-methylenebisacrylamide (MBA). The resulting superabsorbent gel was dried in an oven and then crushed for analysis. The results showed that an increase in chitosan concentration increased the gel fraction, swelling, reusability, and water holding. Meanwhile, an increase in chitosan concentration decreased water retention in sandy soils. The swelling kinetics can be predicted using the pseudo-second-order model with high accuracy (R2 value of 0.99).

Preparation of Crosslinked Poly(acrylic acid-co-acrylamide)-Grafted Deproteinized Natural Rubber/Silica Composites as Coating Materials for Controlled Release of Fertilizer

“…The measurement was performed at 25 and 45 °C. The water retention was calculated as follows [ 28 , 29 ]: …”

Research Advances in Superabsorbent Polymers

“…In recent years, natural polymers, especially polysaccharide-based superabsorbent polymers, have garnered significant attention due to their non-toxicity and good hydrophilicity, biocompatibility, and biodegradability compared with synthetic polymers. The main materials used for superabsorbent polymers are natural polymers, such as cellulose [ 48 , 49 , 50 , 89 ], chitosan [ 51 , 52 , 53 , 90 ], starch [ 54 , 55 , 56 , 57 , 91 ], proteins [ 9 , 58 , 59 , 60 ], amino acids [ 61 , 62 , 63 , 92 ], and alginate [ 64 , 65 , 66 , 93 ].…”

Bioremediation of Crude Oil Contaminated Saline Soil Using a Bacterial Consortium and Different Carriers

“…In part, this was not surprising because chitosan is an organic substance used in agricultural amendments (Rassaei, 2024) to enhance the population of, metabolic activity, and enzyme production by, beneficial soil microorganisms (Shcherban, 2023). Chitosan additions have been shown to improve soil properties including water holding capacity (Jayanudin et al, 2022) and decrease electrical conductivity by modification of cation exchange properties (Rassaei, 2024). While we were unable to specify the mechanisms underway, the application of chitosan likely enhanced these soil properties, facilitating soil conditions that led to enhanced degradation of organic pollutants.…”