Sodium alginate-based composite microspheres for controlled release of pesticides and reduction of adverse effects of copper in agricultural soils

Synthesis and characterization of double-network beads based on sodium alginate grafted polyacrylamide as nitrogen, phosphorus and potassium nutrients carrier

The use of conventional water-soluble mineral fertilizers in modern agriculture brings about serious economic and environmental issues related to the loss of nutrients, the contamination of underground water and the contribution to greenhouse gas emissions. To mitigate these issues, both researchers and industrials are turning to alternative solutions such as slow-release fertilizers. In line with this trend, here we report on the formulation of a novel sodium alginate based slow-release NPK fertilizer beads using sodium alginate as a biopolymer, polyacrylamide as a graft polymer, complex NPK fertilizer as a source of nutrient and calcium (Ca2+) as a crosslinking cation. Five NPK-rich sodium alginate-based slow-release beads were formulated and then extensively characterized by FTIR, XRD and SEM. The swelling capacity in water was also evaluated and was found to be a function of the grafting percentage. The nutrients release profiles were evaluated in water as well as in sandy loamy soil. The release experiments showed that the formulated hydrogel beads displayed a delayed nutrient release profile compared to water-soluble NPK fertilizer. The magnitude of the release was significantly slow down as the grafting rate increased with the graft copolymer at 20 wt% exhibiting the prolonged longevity as compared to the other formulations The cumulative release of nitrogen, phosphorus and potassium from the NPK-rich SA-g-PAM 20 % were 65 52, and 43 % during the first 56 days of release in water and were 23, 16, and 15 % during the first 35 days of release in a sandy loamy soil, respectively. The study of nutrients release kinetics indicated the release behavior of N, P and K in water and soil was controlled by a non-Fickian diffusion mechanism. These performances highlight that the fabricated fertilizer beads could be a promising alternative to water soluble fertilizer in the moder agriculture.

Macromolecules-based encapsulation of pesticides with carriers: A promising approach for safe and effective delivery

The global issue of pollution caused by the misuse and indiscriminate application of pesticides has reached critical levels. In this vein, encapsulating pesticides with carriers offers a promising approach that impacts key parameters such as pesticide release kinetics, stability, and biocompatibility, enhancing the safe and effective delivery of agrochemicals. Encapsulated pesticides hold the potential to reduce off-target effects, decrease environmental contamination, and improve overall crop protection. This review highlights the potential benefits and challenges associated with the use of both organic and in-organic carriers in pesticide encapsulation, and the current state of research in this field. Overall, the encapsulation of pesticides with carriers presents a promising approach for the safe and effective delivery of these vital agricultural compounds. By harnessing the advantages of encapsulation, this technique offers a potential solution to mitigate the adverse effects of conventional pesticides and contribute towards sustainable and environmentally conscious farming practices. Further research and development in this field is necessary to optimize the encapsulation process, carrier properties and advance towards sustainable and environmentally friendly pesticide delivery systems.

Controlled release herbicide formulation for effective weed control efficacy

Controlled release formulation (CRF) of herbicide is an effective weed management technique with less eco-toxicity than other available commercial formulations. To maximise the effectiveness of CRFs however, it is crucial to understand the herbicide-releasing behaviour at play, which predominately depends on the interaction mechanisms between active ingredients and carrier materials during adsorption. In this study, we investigated and modelled the adsorption characteristics of model herbicide 2,4-D onto two organo-montmorillonites (octadecylamine- and aminopropyltriethoxysilane-modified) to synthesise polymer-based CRFs. Herbicide-releasing behaviour of the synthesised CRF microbeads was then analysed under various experimental conditions, and weed control efficacy determined under glasshouse conditions. Results revealed that adsorption of 2,4-D onto both organo-montmorillonites follows the pseudo-second-order kinetics model and is predominately controlled by the chemisorption process. However, multi-step mechanisms were detected in the adsorption on both organoclays, hence intra-particle diffusion is not the sole rate-limiting step for the adsorption process. Both organoclays followed the Elovich model, suggesting they have energetically heterogeneous surfaces. Herbicide-releasing behaviours of synthesised beads were investigated at various pH temperatures and ionic strengths under laboratory and glasshouse conditions. Furthermore, weed control efficacy of synthesised beads were investigated using pot studies under glasshouse condition. Desorption studies revealed that both synthesised microbeads have slow releasing behaviour at a wide range of pHs (5-9), temperatures (25-45 °C), and ionic strengths. The results also revealed that synthesised microbeads have excellent weed control efficacy on different broad-leaf weed species under glasshouse conditions.

Co-production process optimization and carbon footprint analysis of biohydrogen and biofertilizer from corncob by photo-fermentation

In this study, corncob was taken as substrate, the co-production process of biohydrogen and biofertilizer by photo-fermentation was investigated and its carbon footprint analysis was conducted to evaluate the carbon transfer pathway. Biohydrogen was produced by photo-fermentation, and the hydrogen producing residues were immobilized by sodium alginate. Cumulative hydrogen yield (CHY) and nitrogen release ability (NRA) was taken as references, and the effect of substrate particle size on the co-production process was evaluated. Results showed that due to the porous adsorption properties, corncob size of 120 mesh was the optimal one. Under that condition, the highest CHY and NRA were 71.16 mL/g TS and 68.76%, respectively. The carbon footprint analysis indicted that 7.9% carbon element was released as carbon dioxide, 78.3% carbon element was immobilized in the biofertilizer, and 13.8% carbon element was lost. This work is significant of the biomass utilization and clean energy production.