Sulphate-supplemented nitrogen, phosphorus and potassium (NPKS) fertilizer was nanoformulated through ionic gelation of chitosan (CS) and tripolyphosphate (TPP) at pH value of 5.5 to afford a series of nanofertilizers. The CS-TPP nanoparticles and CS-TPP-NPKS nanofertilizers were engineered using different dose of CS (0.125, 0.25, 0.5 and 1%) and NPKS fertilizer (20, 40 and 60 ppm). These nanoparticles were characterized through particle size distribution, zeta potential, SEM, XRD, FTIR, EDX and ICP-MS. The results revealed CS-TPP-NPKS particles with size range of 220–530 nm, polydispersity index (PDI) value between 0.2–0.5 and positive zeta potential. A preliminary evaluation of these nanoparticles along with inorganic NPK and NPKS fertilizers were conducted under greenhouse condition using maize (Zea mays L.) as a test crop. Findings from this study showed that inorganic NPKS (20:7:3:0.5) fertilizer, CS-TPP nanoparticles, and formulated NPKS nanofertilizers gave higher maize plants growth increases than NPK fertilizer and control treatments. The tallest plant (37.73 cm) and highest number of leaves (9) were recorded with the CS-TPP-NPKS nanofertilizer treatment obtained using 1% CS/NPKS (40 ppm). On the other hand, application of the nanoformulated derivative with 0.25% CS/NPKS (20 ppm) produced maize plants with superior chlorophyll content with 12.71 chlorophyll index value. A highly varied magnitude of the coefficient of variation in nutrient contents and uptake was recorded among the treatments. These results revealed that the incorporation of sulphur nutrient into NPK fertilizer and its transformation to nanoparticles have the potential characteristics for effective and productive growth of maize and sustainable agricultural activities.

A novel, modified polypyrrole/m-phenylediamine (PPy–mPD) composite, decorated with magnetite (Fe₃O₄) nanoparticles, and prepared via an in-situ oxidative polymerisation, was investigated. The PPy–mPD/Fe₃O₄ nanocomposite was employed for the removal of highly toxic oxyanion hexavalent chromium Cr(VI) from an aqueous solution. The structure and successful formation of the PPy–mPD/Fe₃O₄ nanocomposite was confirmed and investigated using various techniques. The presence of Fe₃O₄ was confirmed by high resolution transmission electron microscopy, with an appearance of Fe lattice fringes. The estimation of the saturation magnetisation of the nanocomposite, using a vibrating sample magnetometer, was observed to be 6.6 emu/g. In batch adsorption experiments, PPy–mPD/Fe₃O₄ nanocomposite (25 mg) was able to remove 99.6% of 100 mg/L of Cr(VI) at pH 2 and 25 °C. Adsorption isotherms were investigated at different Cr(VI) concentration (100–600 mg/L) and temperature (15–45 °C). It was deduced that adsorption follows the Langmuir model, with a maximum adsorption capacity of 555.6 mg/g for Cr(VI) removal. Furthermore, isotherm data were used to calculate thermodynamic values for Gibbs free energy, enthalpy change and entropy change, which indicated that Cr(VI) adsorption was spontaneous and endothermic in nature. Adsorption–desorption experiments revealed that the nanocomposite was usable for two consecutive cycles with no significant loss of adsorption capacity. This research demonstrates the application potential for the fascinating properties of PPy–mPD/Fe₃O₄ nanocomposite as a highly efficient adsorbent for the removal of heavy metal ions from industrial wastewater.

Development of cost-effective and eco-friendly methods of nanoparticle synthesis could play a crucial role in integrating nanotechnology and phytomedicine for biological applications. In this study, biogenic silver nanoparticles (AgNPs) were synthesized using the ethanolic extract of Pelargonium sidoides DC at 60°C. Formation of nanoparticles was monitored using UV-Visible spectroscopy at different time intervals. A maximum absorption at 456 nm was observed as the reaction time increased, resulting in a red shift of the surface plasmon band (SPB). Attenuated total reflectance Fourier transform infrared spectroscopy (FTIR) revealed the reducing and stabilizing activity of flavonoids, coumarins, tannins, and phenols. Size and morphology of the AgNPs were analysed using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) which indicated the spherical nature of the nanoparticles with sizes ranging from 11 to 90 nm. Further characterization of the AgNPs was carried out using EDS, XRD, and Raman spectroscopy, respectively. Additionally, the AgNPs had a marginally higher antimicrobial activity when compared to the plant extract against Gram-positive Streptococcus pneumoniae (ATCC 27336) and Bacillus cereus (ATCC 10876) and Gram-negative Moraxella catarrhalis (ATCC 25240), Escherichia coli (ATCC 25922), and Pseudomonas aeruginosa (ATCC 27853).

Recent breakthroughs in agro-inputs research have led to the development of nanomaterials that can promote precision agriculture and better environmental security. The agricultural sector is increasingly facing the negative impacts of changing climates due to various stress conditions. To curb this scenario, economical and low-risk practices such as decreasing fertilizer inputs and seed priming have been promoted. In the current study, the H. odoratissimum aqueous extract was used to nucleate the Zn ionic species and grow the zinc oxide nanoparticles (ZnO NPs). The developed nanocomposites and their ionic zinc precursor were then integrated into tripolyphosphate (TPP)-crosslinked chitosan (CS/TPP) nanostructures by ionic gelation. Advanced physicochemical characterization techniques (SEM, EDS, TEM, DLS, FTIR, TGA, and XPS) were exploited to report the morphology, hydrodynamic size, surface charge, and structural organization of the developed nanomaterials. These revealed positively charged particles with hydrodynamic size in the 149–257 nm range. The NPs were used as priming agents for Zea mays seeds. At 0.04%, the ZnO-loaded CS/TPP NPs achieved higher root and shoot elongation in 10-day old seedlings compared to other treatments. The pristine CS/TPP NPs, Zn(II)-laden CS/TPP NPs, and ZnO-loaded CS/TPP NPs at 0.01% significantly promoted the early seedling development of seeds under salt stress. This represents the first report showing ZnO integrated chitosan nanocomposites as an auspicious nanopriming agent for stimulating the seed germination of maize. The study envisages offering perspectives on utilizing green nanotechnology to improve the early seedling development of maize. Furthermore, it has the potential to contribute towards UN SDG 2, thus addressing the threats to global food insecurity and doubling agricultural productivity by 2030.

Respiratory tract infections arise due to the introduction of microbes into the airway, disrupting the normal, healthy, complex interdependent microbiome. The selective disruption of this community can be either beneficial or dangerous. Nanoparticles are a potential tool for modifying this population. Coated silver nanoparticles (AgNPs) were synthesized using ethanolic extracts of Hypoxis hemerocallidea (EEHH), a Southern African plant used extensively in traditional medicine and the source of many bioactive secondary metabolites. The room temperature reaction between silver nitrate and EEHH forms largely spherical AgNPs with an average diameter of 6–20 nm. These nanoparticles show similar levels of antibacterial activity as the broad-spectrum antibiotic streptomycin against Bacillus cereus, Streptococcus pneumonia, Escherichia coli, Pseudomonas aeuroginosa, and Moraxella catarrhalis. However, the AgNPs synergistically increase the antibacterial activity of streptomycin when they are applied in combination (30–52%). AgNPs are reiterated to be promising dual-function antibiotics, synergistically enhancing activity while also acting as delivery agents for small molecules.