Natural Carrageenan/Psyllium Composite Hydrogels Embedded Montmorillonite and Investigation of Their Use in Agricultural Water Management

The carrageenan/psyllium composite hydrogels with embedded montmorillonite have been successfully prepared for the synthesis of a new hydrogel material that is natural, biodegradable and to be used as an absorbent in agriculture. Hydrogels with different composition ratios were found to have the water absorption capacities attaining 2893% and 775%, for free and under load conditions, respectively. The one-way compressional test results have yielded the module values reaching to 226 kPa and showed that they increase with the carrageenan and montmorillonite contents. The hydrogels exhibited different morphological structure depending on the composition ratios. On the other hand, the contribution of the gels to the water absorption and the water retention properties of the soil was investigated by applying various tests to the soil samples mixed with hydrogels. The results showed that including the hydrogels into soil at a ratio of 0.4% increased the water holding capacity of soil from 0.533 to 0.836 g/g and raised the water content % of the soil more than 60%. Additionally, biodegradation test results indicated that depending on the compositional ratios, the hydrogels exhibited a high biodegradation behavior with a weight loss of 39.88% at the end of 35th day. These all finding suggest that these new natural composite hydrogels would be an eco-friendly alternative to present synthetic soil conditioners.