Agrochemicals play an important role in agriculture, in maintaining productivity and defending against disease [1]. Unfortunately, a serious problem has been sparked by the widespread use of agrochemicals. Researchers are looking for approaches to reduce the use of agrochemicals in agriculture while achieving the necessary crop output to feed the world's growing population. Salicylic acid (o-hydroxybenzoic acid) is one of the hormones made by plants, and it has an important effect on a plant's growth and development [2]. In addition to causing a range of physiological and metabolic processes in plants that are involved in plant defense against various biotic and abiotic challenges, it regulates the growth of plants [3]. Generally, Salicylic acid (SA) can be utilized instead of the agrochemicals to accelerate blooming and enhance fruit preservation, as well as to grow crops that are high-quality and yielding, more resilient to adversity and more tolerant of cold [[4], [5], [6]].

Chitosan and chitosan nanoparticles (Cs-NPs) are promising polymeric and bio-based nanocarriers with potential applications in medicine, agriculture, wastewater treatment, and cosmetics, and can create antioxidant and antimicrobial effects after surface modification, leading to future active packaging options [[7], [8], [9]].They have a lot of potential as nanocarriers that encapsulate and release substances under controlled conditions, such as drugs or active compounds [10,11].Applications nanoparticles in drug delivery include the treatment of ocular infections, gastrointestinal disorders, lung disorders, cancer, and drug delivery to the brain [[12], [13], [14]].

Lignocellulosic biomass and their pulping-by products, rich in carbon, have potential in various fields such as wood composites, polymer composite, paper sheets, activated carbons, cement-mortar and hydrogels [[15], [16], [17], [18], [19], [20], [21]]. Lignin, a second-highest constituent, is underutilized. Nanoscale lignin nanoparticles (LNPs) can enhance surface area and properties, leading to controllable synthesis and improved antibacterial, antiradical, emulsion stabilization, and catalysis properties [22]. LNPs have been synthesized using various methods, including self-assembly, solvent exchange, acid precipitation, carbon dioxide saturation, aerosol processing, high shear/pressure homogenization, and ultrasonication [23].

The novelty of this study arises from using nitrogen-containing black liquor (BL) in preparation of LNPs, followed by chelation with chitosan nanoparticles (Cs-NPs) to produce nanocomposite gels that can act as a salicylic acid delivery system. The gels from chelation of LNPs with cationic starchsubstituted Cs-NPsis also prepared for comparison.Prior to the current work, the prepared nanomaterials (LNP and Cs-NPs) are characterized by TEM, ATR-FTIR, and XRD analysis.The nanocomposite systems loaded with SA are compared in order to investigate the release pattern. The encapsulation, release, kinetics, thermal, FTIR, and SEM are used to examine SA-loaded nanocomposites. This work is a continuation of our trials to reduce the negative environmental effects of BLs in the production of LNPs to control the release of monoammonium phosphate (MAP) fertilizer [24].