Composite Polymers from Leather Waste to Produce Smart Fertilizers

Abstract

The leather industry is facing important environmental issues related to waste disposal. The waste generated during the tanning process is an important resource of protein (mainly collagen) which can be extracted and reused in different applications (e.g., medical, agricultural, leather industry). On the other side, the utilization of chemical fertilizers must be decreased because of the negative effects associated to an extensive use of conventional chemical fertilizers. This review presents current research trends, challenges and future perspectives with respect to the use of hide waste to produce composite polymers that are further transformed in smart fertilizers. Hide waste contains mostly protein (collagen that is a natural polymer), that is extracted to be used in the cross-linking with water soluble copolymers to obtain the hydrogels which are further valorised as smart fertilizers. Smart fertilizers are a new class of fertilizers which allow the controlled release of the nutrients in synchronization with the plant’s demands. Characteristics of hide and leather wastes are pointed out. The fabrication methods of smart fertilizers and the mechanisms for the nutrients release are extensively discussed. This novel method is in agreement with the circular economy concepts and solves, on one side, the problem of hide waste disposal, and on the other side produces smart fertilizers that can successfully replace conventional chemical fertilizers.

Production, Mechanisms, and Performance of Controlled-Release Fertilizers Encapsulated with Biodegradable-Based Coatings

“…A new agritech revolution is springing up, driven by the developments in information technology, robotics, genetics, plant probiotics, and the evolution of controlled-release systems . In the specific case of CRFs, an important achievement is focused on: low-solubility fertilizers, coated fertilizers, superabsorbent biobased polymers (SABs), and nanofertilizers (specifically, nanomaterials used as macronutrient carriers). , SABs have attracted considerable attention due to their three-dimensional cross-linked polymer networks that have a great potential to absorb and retain large amounts of water, while reducing irrigation times. , The recent development of nanofertilizers with high surface areas and sorption capacity for nutrients improves the NUE in plants by a faster response through different adsorption routes (i.e., seed treatment, soil amendment, and foliar spray) (Figure ). ,, Different studies have demonstrated that nanofertilizers are an emerging CRF alternative to improve NUE. ,− For instance, in both soil and water, hybrid nanofertilizers increased the NUE in A. esculentus , as compared to a conventional fertilizer .…”

“…211,213 SABs have attracted considerable attention due to their three-dimensional cross-linked polymer networks that have a great potential to absorb and retain large amounts of water, while reducing irrigation times. 159,160 The recent development of nanofertilizers with high surface areas and sorption capacity for nutrients improves the NUE in plants by a faster response through different adsorption routes (i.e., seed treatment, soil amendment, and foliar spray) (Figure 5). 161,162,214 Different studies have demonstrated that nanofertilizers are an emerging CRF alternative to improve NUE.…”

The Influence of the Content of Recycled Natural Leather Residue Particles on the Properties of High-Density Fiberboards

“…Some research has focused on the use of leather waste in wood-based composites, highlighting its potential as a reinforcing material. These review articles [14,15] present current research trends and prospects for the use of leather waste to produce composite polymers that are further transformed, for example into smart fertilizers. They produced value-added boards using leather particles and partially liquefied bamboo fiber.…”

Advanced Collagen-Based Composites as Fertilizers Obtained by Recycling Lime Pelts Waste Resulted during Leather Manufacture

“…Our previous works [ 21 , 22 , 23 ] reported on the synthesis and physical–chemical characterization of novel collagen-based hydrogels by recycling the protein hide waste from the leather industry in ecological conditions and obtaining advanced collagen-based composites with N, P, and K nutrients encapsulated and functionalized with two synthetic polymers, namely poly-acrylamide and poly(sodium 4-styrenesulfonate-co-glycidyl methacrylate) (P(SSNa-co-GMAx), and two natural compounds, namely starch and dolomite, in order to be used as fertilizers for poor soil amendment. The reason why the last two natural compounds were selected for collagen functionalization was to test their efficacy on improving fertilizer quality by using starch as an organic and dolomite as a mineral amendment, as they are both available in high amounts and as waste to be recycled.…”