Highly degradable chitosan-montmorillonite (MMT) nanocomposite hydrogel for controlled fertilizer release  

作　　者：Zeou Dou Maria Vitoria Bini Farias Wensi Chen Dongjing He Yuhang Hu Xing Xie 

机构地区：[1]School of Civil and Environmental Engineering,Georgia Institute of Technology,Atlanta,GA 30332,USA [2]George W.Woodruff School of Mechanical Engineering,Georgia Institute of Technology,Atlanta,GA 30332,USA [3]School of Chemical and Biomolecular Engineering,Georgia Institute of Technology,Atlanta,GA 30332,USA

出　　处：《Frontiers of Environmental Science & Engineering》2023年第5期1-11,共11页环境科学与工程前沿（英文）

基　　金：performed in part at the Georgia Tech Institute for Electronics and Nanotechnology,a member of the National Nanotechnology Coordinated Infrastructure,which is supported by the National Science Foundation(Grant ECCS-1542174).

摘　　要：Fertilizer consumption is increasing drastically along with the rapid expansion of farming in response to the ever-growing population. However, a significant portion of the nutrients in traditional fertilizers is lost during leaching and runoff causing economic loss and environmental threats. Polymer-modified controlled-release fertilizers provide an opportunity for mitigating adverse environmental effects and increasing the profitability of crop production. Here, we present a cheap and easy-to-fabricate controlled-release fertilizer excipient based on hydrogels scaffolded by safe and biodegradable chitosan and montmorillonite (MMT) nanoclays. By introducing elastic and flexible physical crosslinking induced by 2-dimensional (2D) MMT nanoflakes into the chitosan hydrogel, highly swellable and degradable chitosan-MMT nanocomposites were fabricated. The addition of MMT into the chitosan hydrogels enhanced the total release of phosphorous (P) and potassium (K), from 22.0 % to 94.9 % and 9.6% to 31.4 %, respectively, compared to the pure chitosan gel. The chitosan-MMT nanocomposite hydrogel achieved a well-controlled overall fertilizer release in soil. A total of 55.3 % of loaded fertilizer was released over 15 d with a daily release of 2.8 %. For the traditional fertilizer podwer, 89.2 % of the fertilizer was washed out during the first irrigation under the same setup. In the meantime, the nanocomposites improved the water retention of the soil, thanks to its excellent water absorbency. Moreover, the chitosan-MMT nanocomposite hydrogels exhibited high degradation of 57 % after swelling in water for 20 d. Such highly degradable fertilizer excipient poses minimal threat to the long-term fertility of the soil. The engineered Chitosan-MMT biopolymer scaffold as a controlled-release fertilizer excipient provides a promising opportunity for advancing sustainable agriculture.

关 键 词：BIOPOLYMER Hydrogel Controlled-release fertilizer NANOCLAY Nanocomposite 

分 类 号：O63[理学—高分子化学]