A series of κ-carrageenan (κ-CG) hydrogels were prepared by using glutaraldehyde (GA) as crosslinker for controlled releasing of copper and manganese micronutrients. The hydrogels were characterized by gel content, swelling and degradation tests, Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR) and Scanning Electron Microscope (SEM) observations. The variations of swelling percentages (S%) with time, temperature and pH were determined for all hydrogels. As the amounts of crosslinker increased, S% decreased regularly in contrast to gel content results. The higher swelling values were obtained in basic medium than acidic and neutral mediums for all κ-CG hydrogels. Releasing of copper and manganese micronutrients from κ-CG hydrogels was investigated in water and soil. A simulated releasing model was also applied to estimate the releasing behaviors in agricultural irrigations. In all release studies, the cumulative release values increased with decreasing GA amounts. The release kinetic parameters were also calculated. It was detected that the releasing of micronutrients in soil was slower than that in water.

中文翻译：

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用于铜锰微量营养素控释的κ-角叉菜胶水凝胶的制备与表征

以戊二醛（GA）为交联剂，制备了一系列κ-角叉菜胶（κ-CG）水凝胶，用于铜和锰微量营养素的受控释放。水凝胶的特征在于凝胶含量、溶胀和降解测试、衰减全反射傅立叶变换红外光谱 (ATR-FTIR) 和扫描电子显微镜 (SEM) 观察。测定了所有水凝胶的溶胀百分比 (S%) 随时间、温度和 pH 值的变化。随着交联剂用量的增加，与凝胶含量结果相反，S% 有规律地下降。对于所有 κ-CG 水凝胶，在碱性介质中获得的溶胀值高于酸性和中性介质。在水和土壤中研究了铜和锰微量营养素从 κ-CG 水凝胶中的释放。还应用模拟释放模型来估计农业灌溉中的释放行为。在所有释放研究中，累积释放值随着 GA 量的减少而增加。还计算了释放动力学参数。结果表明，土壤中微量元素的释放速度比水中慢。