Modification of TEMPO-oxidized cellulose nanofibers as a source of potassium and its impact on onion plant

Abstract

This research study aims to improve the productivity and vegetative growth characteristics of onion to meet local demands and the volume of exports. This was done by the application of foliar nano-fertilizers based on cellulose nanofibers (CNF). TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl) -oxidized cellulose nanofibers (TO-CNFs) were fabricated using the TEMPO-oxidized method in the presence of sodium or potassium hydroxide to obtain sodium carboxylate TO-CNFs (N-CNF) and potassium carboxylate TO-CNFs (K-CNF), respectively. Also, potassium acrylate was used in grafting N-CNF to get potassium polyacrylate-g-sodium carboxylate TO-CNFs (G-CNF). The prepared CNFs were described via various techniques such as FTIR, SEM, TGA, and XRD. X-ray analysis demonstrated that N-CNF, K-CNF, and G-CNF consisted of a crystalline domain of crystallinity index 0.45, 0.41, and 0.55, respectively. K-CNF showed marginally lower thermal stability than N-CNF influenced by its crystalline properties. The vegetative growth and the yield of onion plants, plus the content of photosynthetic pigments, minerals, cellulose, hemicellulose, and lignin, as well as total phenols, flavonoids, and indoles, were studied. The results showed that the application of K-CNF as a foliar nano-fertilizer improved the onion yield and the content of elements, protein, total soluble solid, phenols, and indoles as well as the content of cellulose and lignin