A Novel Hydrogel Based on Renewable Materials for Agricultural Application

Abstract

This study details the design and characterization of a new, biodegradable, and renewable whey/cellulose-based hydrogel (i.e., agricultural hydrogel). This was formulated from cellulose derivatives (carboxymethylcellulose (CMC) and hydroxyethylcellulose (HEC)) and acid whey cross-linked with citric acid, with the aim to obtain an agricultural product with a high swelling capacity to uphold the quality of soil and conserve water resources. With regard to the swelling behaviour of the prepared hydrogels, the authors initially assessed the swelling ratio and capacity for water uptake. Evaluating the chemical structure of the hydrogel and its thermal and viscoelastic properties involved performing Fourier transform infrared spectroscopy, differential scanning colorimetry, thermal gravimetric analysis, and rheological measurement of the hydrogel films. According to preliminary results, sufficient swelling capacity and stiffness were observed in a hydrogel prepared with 3% CMC and HEC, cross-linked with 5% citric acid. Moreover, the kinetics of water uptake revealed a promising capacity that was sustainable after 5 drying and swelling cycles. The results confirmed that the stability of the hydrogel was enhanced by the presence of the citric acid. As a consequence, it is necessary to utilize an appropriate cross-linking concentration and abide by certain conditions to ensure the swelling properties of the prepared hydrogel are sufficient. Further investigation of the topic, especially in relation to applications in soil, could confirm if the whey-cellulose-based hydrogel is actually suitable for agricultural use, thereby contributing to the advancement of sustainable arable farming.

The Synergic Effect of Whey-Based Hydrogel Amendment on Soil Water Holding Capacity and Availability of Nutrients for More Efficient Valorization of Dairy By-Products

“…Also, the positive microbial biomass stimulation of whey makes it a candidate substrate for appropriate in situ bioremediation of different compounds [60]. The pH swing remains also very important because a significant effect of pH on the swelling ratio of natural-based hydrogels was observed under laboratory [36] and field conditions [20].…”

“…The citric acid in anhydrous form (Lach-Ner, Neratovice, Czech Republic) was added at concentrations equal to 10% wt as a cross-linking agent. The hydrogel samples were prepared according to the procedure detailed by Durpekova et al [36]. The hydrogel samples were analyzed by accredited methods (Table 1) in the Research Institute for Soil and Water Conservation.…”

“…Since the laboratory characterization of the novel whey/cellulose hydrogel crosslinked by citric acid showed a decent capacity for water uptake together with desirable properties of thermal stability and viscoelasticity [36], the objective of this study was to explore the effects of different soil-hydrogel mixtures on several critical soil parameters under controlled experimental conditions. The investigated soil parameters were chosen to cover the basic desirable properties (water retention characteristics), synergic ameliorative effects (nutritional status of soil), and the potentially adverse effects (undue pH drop, excessive mobilization of soil macro-elements).…”

Biopolymer Hydrogel Based on Acid Whey and Cellulose Derivatives for Enhancement Water Retention Capacity of Soil and Slow Release of Fertilizers

“…Samples were prepared according to a procedure described in Durpekova et al [ 13 ], with minor modification. Briefly, a mixture of the CMCNa and HEC at a weight ratio equal to 3:1 and total polymer concentration of 3 wt% was dissolved in the untreated acid whey under mechanical stirring at room temperature (20–22 °C) for 24 h until a homogeneous solution was obtained.…”

Cellulose: a fascinating biopolymer for hydrogel synthesis

“…173 Most of the chemically crosslinked hydrogels that are being synthesized for various applications use toxic chemicals as crosslinkers. Das et al, 9 Demitri et al, 60,61 and S. Durpeko et al 174 have synthesized carboxymethyl cellulose (CMC) and hydroxyethyl cellulose (HEC) based hydrogels for agriculture applications using the non-toxic natural crosslinker citric acid (CA). The presence of HEC in the CMC/HEC hydrogel structure has promoted the formation of intermolecular bonding between polymer chains, resulting in a stable and robust hydrogel structure.…”