Synthesis and Characterization of Controlled-Release Urea Fertilizer from Superabsorbent Hydrogels

Abstract

It is very important to develop controlled-release fertilizers to ensure efficiency and environmental protection. This study aims to make a superabsorbent hydrogel-based controlled-release urea fertilizer. Superabsorbent hydrogels were prepared from the cellulose of corn cobs cross-linking with epichlorohydrin, and then an amount of urea as a fertilizer was stored inside the hydrogels (GEL-A). The GEL-A functionalization with carboxy-methyl was also carried out in this study to improve the hydrophilicity of hydrogels (GEL-B). GEL-A and GEL-B were immersed in water at a certain pH and temperature range and the urea concentration released from the hydrogels was monitored by a spectrophotometer. The results showed that the urea released by GEL-A and GEL-B was not much different. Respectively, the urea efficiency of GEL-A and GEL-Bwas around 5.29% and 5.56% for 180 min. The urea released from both hydrogels was not significantly affected by changes in the temperature of the solution. Urea release was influenced by pH, and the rate of urea release of GEL-B was faster than GEL-A, so pH control was needed in the application of this slow-release fertilizer.

Multifunctional Hydrogels Based on Cellulose and Modified Lignin for Advanced Wounds Management

“…Generally, the cross-linking process with ECH that takes place in various alkaline media is controlled by the synergy between the chemical and physical cross-linking processes of the polymer chains, and more precisely by (i) the chemical cross-linking processes, through the etherification reaction between the OH groups of ECH and those of the cellulose chains, as well as by (ii) the physical cross-linking process between the OH groups of the polymeric chains, with the reconstruction of hydrogen bonds [28].…”

Fertilizer technology based on optimized nitrogen release from urea‐loaded natural superabsorbent carriers

“…Matching plant demand with supply of nutrients during different growth stages is a primary prerequisite of sustainable agriculture. Nitrogen (N) is the key plant nutrient greatly affecting the crop yield of all major agricultural plants (Cao et al, 2017; Cassman et al, 2002; Chen et al, 2006; Cheng et al, 2018; Ciampitti et al, 2015; Ciampitti & Vyn, 2012; Fernandez et al, 2020; Gehl et al, 2005; Guo et al, 2020; Liu et al, 2019; Majeed et al, 2015; Muharam et al, 2020; Ransom et al, 2020; Soufizadeh et al, 2018; Tong et al, 2009). Up to 15% of the nitrogen demand can be supplied by foliar application with the intake efficiency of over 80% (Haegele et al, 2013).…”

Sugarcane bagasse derived phosphorylated cellulose as substrates for potassium release induced by phosphates surface and drying methods

“…The capability to retard or control plant nitrogen, phosphorous, and potassium macronutrients from varied fertilizer sources, i.e., urea ((NH 2 ) 2 CO), potassium sulfate (K 2 SO 4 ), diammonium hydrogen phosphate ((NH 4 ) 2 HPO 4 ), dipotassium hydrogen phosphate (K 2 HPO 4 ), over a prolonged time interval can also minimize environmental pollution from nutrient loss (Chen et al, 2018). The enhanced efficiency fertilizers (EEFs) based on cellulose or its derivatives have been predominantly reported as hydrogels (Bortolin et al, 2013;Kenawy et al, 2018;Li et al, 2015;Mohammadi-Khoo et al, 2016;Muharam et al, 2020;Olad et al, 2018;Rop et al, 2018;Senna et al, 2015;. For instance, the grafting copolymerization of sawdust cellulose, acrylic acid, acrylamide, and urea was performed using N, N ′ -methylenebis as crosslinker and potassium persulfate as an initiator to synthesize hydrogel fertilizers for slow-release of urea achieving 82.4% of release in water for 8 h .…”