Browsing by Author "Irewale, Adewale Tolulope"

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    Utilization of functionalized biochar derived from water hyacinth eichhornia crassipies as green nano-fertilizers
    (Federal University of Technology, Owerri, 2025-10) Irewale, Adewale Tolulope
    This study investigated the production, characterization, and application of nano-biofertilizer synthesized from biochar (BC) derived from the aerial tissues of Eichhornia crassipes (water hyacinth), an invasive aquatic plant known for rapid growth and nutrient uptake that has adversely affected the aquatic ecosystem. BC was produced from its leaves (D1) and stems (D2) via pyrolysis at 600°C with residence times of 15, 30, 45, and 60 minutes, yielding 31% and 34% respectively. Incomplete carbonization was observed at residence time of 15 minutes while optimum pyrolysis occurred at 30 - 60 minutes. SEM and FTIR analyses revealed porous structures with surface functional groups including –COOH, –OH, C=C, and –S=O in but biomasses, although predominantly in D1. The biochar was alkaline (average pH 10.7), exhibited liming capacities of 14.76–28.94% CaCO₃ equivalent, zeta potentials of –34 to –38 mV, and particle sizes ranging from 146 to 583 nm. Although, deficient in copper and zinc, high nutrient availability was recorded with nitrogen (34,550 ppm), phosphorus (56 ppm), potassium (609 ppm), and water holding capacities between 1.58 and 2.26 g/g. BET isotherm modeling showed surface areas of 236.44–249.41 m²/g and pore volumes of 0.061–0.087 cm³/g, indicating mesoporous to microporous structures suitable for nanonutrient adsorption. Molecular dynamics simulations revealed thermodynamically favorable adsorptions between BC and ZnO and/or CuO nanonutrients, with a higher affinity for CuO. Comparative pilot field trials with nano-biofertilizer (NF) applied at 10 g, 20 g, and 40 g per 10 kg soil and a conventional fertilizer (CF) at 15g per 10kg soil (per manufacturer recommendation) showed that 10 g NF significantly enhanced growth and physiological parameters over other treatments. CF application resulted in higher plant mortality, indicating possible phytotoxicity of CF under the pilot field conditions. Comparative data obtained for plant height, leaf nitrogen content, chlorophyll concentration, number and surface area of leaves support the potential of biochar-based nanofertilizers as a low-dose, sustainable alternative to chemical fertilizers. Further studies are recommended to validate the predictions from molecular dynamics simulations, as well as to assess the environmental safety and scalability of the nanofertilizer in larger field trials.