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

This study optimizes CO 2 -activated biochar production from vine shoots for adsorbing contaminants of emerging concern (CECs), focusing on pesticides acetamiprid, metalaxyl, and penconazole. Nine variables affecting biochar synthesis and adsorption capacity were examined using a two-step Design of Experiments (DOE). First, a Plackett–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 four key factors—pyrolysis temperature, pyrolysis time, activation temperature and activation time—to optimize both biochar synthesis yield and adsorption performance. Predictive models highlighted the importance of activation conditions in optimizing biochar's utility. Key physicochemical characterization confirmed the optimized biochar features. The best conditions, involving activation at 850 °C for 30 minutes, yielded biochar with a surface area of 740 m²/g, showing adsorption capacities of 172 mg/g for acetamiprid, 92 mg/g for metalaxyl, and 210 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 into sustainable 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. • Yield and adsorption capacity of vine-pruning biochar were optimized via DoE. • Nine synthesis factors were analyzed using Plackett-Burman and central composite designs. • Predictive models emphasized activation temperature and time for biochar effectiveness. • Activation at 850 °C for 30 minutes resulted in a 740 m²/g surface area biochar. • Biochar’s CEC adsorption was comparable to commercial activated carbon.