Operational parameters affecting synthesis yield and adsorption capacity of vine-pruning derived biochar for pesticide removal: Impact and modelling

Abstract

This study optimizes CO2-activated biochar production from vine shoots for adsorbing contaminants of emergingconcern (CECs), focusing on pesticides acetamiprid, metalaxyl, and penconazole. Nine variables affecting biocharsynthesis and adsorption capacity were examined using a two-step Design of Experiments (DOE). First, aPlackett–Burman Design screened five factors: biomass bed height, pyrolysis gas composition, pyrolysis gas flow,activation gas flow rate, and biomass particle size. Next, a Face-Centered Central Composite Design refined fourkey factors—pyrolysis temperature, pyrolysis time, activation temperature and activation time—to optimize bothbiochar synthesis yield and adsorption performance. Predictive models highlighted the importance of activationconditions in optimizing biochar’s utility. Key physicochemical characterization confirmed the optimized biocharfeatures. The best conditions, involving activation at 850 ◦C for 30 minutes, yielded biochar with a surfacearea of 740 m²/g, showing adsorption capacities of 172 mg/g for acetamiprid, 92 mg/g for metalaxyl, and210 mg/g for penconazole. The adsorption capacity of acetamiprid significantly surpasses reported efficiencies,with no comparable studies available for metalaxyl and penconazole. This research offers valuable insights intosustainable viticultural waste management, demonstrating the potential of vine-pruning biochar as an effective,eco-friendly adsorbent for CECs removal and laying groundwork for further environmental applications.