Synthesis And Ecotoxicological Evaluation of Gelatin‐Urea Delivery System for Biostimulation Purposes

Abstract

In this study, the behavior of slow‐release urea capsules is investigated for bioremediation purposes. The urea capsules (u/PUA/HG) are produced by an emulsion system (O/W) containing a double coating of polyurea (internal) and gelatin hydrogel (external), using for both toluene‐2,4‐diisocyanate (TDI) as a reagent. The slow‐release system are characterized by Fourier transform‐infrared spectroscopy by ATR, optical microscopy, swelling index test (%), and urea release test (%). Eco‐toxicological studies are carried out to evaluate the toxicity of composites using germination (and root growth) of lettuce seeds. Also, preliminary study is conducted based on assessed of the Pseudomonas aeruginosa microbial behavior in the presence of composites. The characterization results indicate the effective coating of the urea granules. However, the FTIR analysis reveals an excess of unreacted TDI in the u/PUA/HG sample. Furthermore, there is an observed inhibition of both root growth and germination that corresponds to the quantity of the sample and TDI used. Notably, there is a notable 70% increase in microbial growth compared to the control group after 48 h. Upon concluding the urea release test spanning 144 h, a significant 43% reduction is observed for u/PUA/HG at 24°C. Additionally, there is a delay of 119 h in the total release time at 36°C, when compared to u/PUA. Collectively, the outcomes of this study strongly suggest the potential of u/PUA/HG as a bio‐stimulant, particularly in its effect on P. aeruginosa growth. These findings highlight its promising application as a bioremediator in the future.