Enhancing Imidacloprid Adsorption Capability in Sugarcane Mill Mud through Hydrothermal Activation

The sugar industry in Australia produces a significant amount of waste, with an annual yield of four million tonnes of sugar products derived from thirty million tonnes of sugarcane. One of the notable by products is sugarcane mill mud. This work is focused on the hydrothermal activation of mill mud waste sourced from a sugar mill. The objective was to produce an economically feasible adsorbent material suitable for pesticide adsorption applications. Significant alterations were noted in the mill mud that underwent hydrothermal activation, encompassing discernible chemical and physical modifications, accompanied by altered surface properties. Comprehensive characterisations using electron microscopy and X-ray photoelectron spectroscopy studies. The hydrothermal activation process resulted in a transformation of the physical structure, shifting from agglomerated multiple layers to discrete forms characterised by single layers. The evaluation of the highest adsorption capacities for organic compounds, carried out using the methylene blue dye assay, demonstrated a significant increase at least three times after activation. It is noteworthy that the hydrothermally activated mill mud displayed a mono-layer adsorption profile, which contrasts with the untreated mill mud sample. The adsorptivity of the activated mill mud was assessed in relation to imidacloprid, a commonly used pesticide in Australian sugarcane farms. The objectives of this evaluation were to assess the efficacy of the mill mud as an adsorbent for pesticide. Evidently, the adsorption capacity exhibited equivalence to that of the reference activated carbon, surpassing the commercially available coconut activated carbon. This discovery highlights the potential of its application as a protective measure against pesticide runoff barrier in sugarcane plantation.