Biodegradable Starch Sachets Reinforced with Montmorillonite for Packing ZnO Nanoparticles: Solubility and Zn2+ Ions Release

Abstract

Agriculture's importance in human lives and the economy has directed studies to improve crop production. An essential challenge for improving fertilizer e cacy is reducing losses due to leaching and increasing the nutrients supplies. In this context, biodegradable sachets stand out as internal packaging instead of direct insertion into the polymer matrix, facilitating the system processing and making it easier to adapt the soil's nutritional quantity. Thus, the present work aimed to increase the zinc oxide (ZnO) solubility by obtaining nanoparticles using top-down and bottom-up approaches and packaging them in montmorillonite (MMT) reinforced starch sachets. The different diameters and forms of the ZnO nanoparticles were evaluated to understand the solubility dependence on these parameters. In this way, the top-down process was performed for the attritor milling method allowing the nanoparticles with about 71 nm average diameter and greater homogeneity than the commercial one (approximately 174 nm). The milled ZnO nanoparticles presented better solubility than those synthesized bottom-up processes and the commercial ones, reaching a 90 to 100% solubility plateau in 48 h. Concerning starch sachets, the 1% MMT (w w − 1 ) insertion in the polymeric matrix promoted increased water vapor barrier and mechanical properties, improving the tensile strength. In the solubility test for nanoparticulate ZnO packed in sachets, similar behaviors to free ZnO were observed due to the high a nity of the starch matrix with water.Therefore, starch sachet systems with improved properties from the MMT reinforcement insertion showed as an alternative source of Zn 2+ ions to minimize losses during application.

Antifungal and ultraviolet–visible barrier properties in starch films reinforced with CuO nanoparticles

“…According to Sun et al, 39 this improvement is explained by the adequate interface between the filler nanometric with the polymeric matrix, favoring the stress transfer. Peres et al 47 obtained films of corn starch reinforced with montmorillonite (MMT). The film reinforced with 1% (w w −1 ) MMT showed the best mechanical strength results, increasing the tensile strength from 2.5 to 3.8 MPa and maintaining the deformation at 60% compared to the pure film.…”

Photocatalytic Degradation of Methylene Blue from Aqueous Solutions by Using Nano-ZnO/Kaolin-Clay-Based Nanocomposite

“…Nanocomposite material developed from clay and ZnONPs is one of the most promising materials for the photocatalytic disintegration of dyes [42]. Several investigators have developed nanocomposites from clay like montmorillonite (MMT) [43] and halloysite (HC) [44][45][46]. Furthermore, a few researchers have employed NPs of silver and zinc oxide for surface modification of clay and the subsequent development of nanocomposites.…”