Fluidized-Bed Coating with Sodium Sulfate and PVA−TiO2, 1. Review and Agglomeration Regime Maps

Sustainable SMART fertilizers in agriculture systems: A review on fundamentals to in-field applications

Agriculture will face the issue of ensuring food security for a growing global population without compromising environmental security as demand for the world's food systems increases in the next decades. To provide enough food and reduce the harmful effects of chemical fertilization and improper disposal or reusing of agricultural wastes on the environment, will be required to apply current technologies in agroecosystems. Combining biotechnology and nanotechnology has the potential to transform agricultural practices and offer answers to both immediate and long-term issues. This review study seeks to identify, categorize, and characterize the so-called smart fertilizers as the future frontier of sustainable agriculture. The conventional fertilizer and smart fertilizers in general are covered in the first section of this review. Another key barrier preventing the widespread use of smart fertilizers in agriculture is the high cost of materials. Nevertheless, smart fertilizers are widely represented on the world market and are actively used in farms that have already switched to sustainable technologies. The advantages and disadvantages of various raw materials used to create smart fertilizers, with a focus on inorganic and organic materials, synthetic and natural polymers, along with their physical and chemical preparation processes, are contrasted in the following sections. The rate and the mechanism of release are covered. The purpose of this study is to provide a deep understanding of the advancements in smart fertilizers during the last ten years. Trends are also recognized and studied to provide insight for upcoming agricultural research projects.

Potential of Rejected Sago Starch as a Coating Material for Urea Encapsulation

Increases in food production to meet global food requirements lead to an increase in the demand for nitrogen (N) fertilizers, especially urea, for soil productivity, crop yield, and food security improvement. To achieve a high yield of food crops, the excessive use of urea has resulted in low urea-N use efficiency and environmental pollution. One promising alternative to increase urea-N use efficiency, improve soil N availability, and lessen the potential environmental effects of the excessive use of urea is to encapsulate urea granules with appropriate coating materials to synchronize the N release with crop assimilation. Chemical additives, such as sulfur-based coatings, mineral-based coatings, and several polymers with different action principles, have been explored and used for coating the urea granule. However, their high material cost, limited resources, and adverse effects on the soil ecosystem limit the widespread application of urea coated with these materials. This paper documents a review of issues related to the materials used for urea coating and the potential of natural polymers, such as rejected sago starch, as a coating material for urea encapsulation. The aim of the review is to unravel an understanding of the potential of rejected sago starch as a coating material for the slow release of N from urea. Rejected sago starch from sago flour processing is a natural polymer that could be used to coat urea because the starch enables a gradual, water-driven mechanism of N release from the urea-polymer interface to the polymer-soil interface. The advantages of rejected sago starch for urea encapsulation over other polymers are that rejected sago starch is one of the most abundant polysaccharide polymers, the cheapest biopolymer, and is fully biodegradable, renewable, and environmentally friendly. This review provides information on the potential of rejected sago starch as a coating material, the advantages of using rejected sago starch as coating material over other polymer materials, a simple coating method, and the mechanisms of N release from urea coated with rejected sago starch.

Microfluidic encapsulation for controlled release and its potential for nanofertilisers

Nanotechnology is increasingly being utilized to create advanced materials with improved or new functional attributes. Converting fertilizers into a nanoparticle-form has been shown to improve their efficacy but the current procedures used to fabricate nanofertilisers often have poor reproducibility and flexibility. Microfluidic systems, on the other hand, have advantages over traditional nanoparticle fabrication methods in terms of energy and materials consumption, versatility, and controllability. The increased controllability can result in the formation of nanoparticles with precise and complex morphologies (e.g., tuneable sizes, low polydispersity, and multi-core structures). As a result, their functional performance can be tailored to specific applications. This paper reviews the principles, formation, and applications of nano-enabled delivery systems fabricated using microfluidic approaches for the encapsulation, protection, and release of fertilizers. Controlled release can be achieved using two main routes: (i) nutrients adsorbed on nanosupports and (ii) nutrients encapsulated inside nanostructures. We aim to highlight the opportunities for preparing a new generation of highly versatile nanofertilisers using microfluidic systems. We will explore several main characteristics of microfluidically prepared nanofertilisers, including droplet formation, shell fine-tuning, adsorbate fine-tuning, and sustained/triggered release behavior.

Controlled Release Fertilizers: A Review on Coating Materials and Mechanism of Release

Rising world population is expected to increase the demand for nitrogen fertilizers to improve crop yield and ensure food security. With existing challenges on low nutrient use efficiency (NUE) of urea and its environmental concerns, controlled release fertilizers (CRFs) have become a potential solution by formulating them to synchronize nutrient release according to the requirement of plants. However, the most significant challenge that persists is the "tailing" effect, which reduces the economic benefits in terms of maximum fertilizer utilization. High materials cost is also a significant obstacle restraining the widespread application of CRF in agriculture. The first part of this review covers issues related to the application of conventional fertilizer and CRFs in general. In the subsequent sections, different raw materials utilized to form CRFs, focusing on inorganic and organic materials and synthetic and natural polymers alongside their physical and chemical preparation methods, are compared. Important factors affecting rate of release, mechanism of release and mathematical modelling approaches to predict nutrient release are also discussed. This review aims to provide a better overview of the developments regarding CRFs in the past ten years, and trends are identified and analyzed to provide an insight for future works in the field of agriculture.

Flexible polyvinyl alcohol/2-hydroxypropanoic acid films: effect of residual acetyl moieties on mechanical, thermal and antibacterial properties

This work ascertains the effect of the degree of hydrolysis of polyvinyl alcohol under extended interaction with 2-hydroxypropanoic acid (lactic acid). Systems based on three different types of polyvinyl alcohol matrices (of hydrolysis degree 80, 88 and 98 mol%) and lactic acid were characterized according to their physicochemical, mechanical and thermal properties. An agar diffusion test and the dilution and spread plate technique were conducted to facilitate antibacterial activity to counteract Staphylococcus aureus and Escherichia coli. A mathematical model was applied to the experimental data to estimate the antibacterial efficacy of the resultant flexible films.

Effect of the borax mass and pre-spray medium temperature on droplet size and velocity vector distributions of intermittently sprayed starchy solutions

The droplet size–velocity field plot of the modified tapioca starch solution atomized using an airless full cone nozzle.