Meta-analysis and empirical research on the effectiveness of biochar in remediating tetracyclines pollution in water bodies

The rapid increase in tetracycline pollution from intensive aquaculture necessitates urgent action to reduce tetracycline levels in water bodies, as its stability promotes antibiotic resistance, disrupts aquatic ecosystems, and poses health risks to humans through bioaccumulation. Current treatment methods like ozone oxidation are often costly or ineffective. Biochar, recognised for its cost-effectiveness and adsorption capacity, provides a promising solution. Through a meta-analysis of 110 research articles integrating 537 observations focused on plant-based biomass, this study identified the following: 1) key factors influencing biochar’s adsorption of tetracyclines include preparation processes and environmental conditions; 2) higher pyrolysis temperatures can boost adsorption capacity, especially above 600 °C; 3) pre-treatment using acids or salts is more effective than other modifiers. Additionally, a linear mixed-effects model predicted that specific pyrolysis temperatures combined with acid or salt modification would produce biochar with superior performance. Verification experiments with pine, poplar, and straw from wheat, rice, and corn modified with salts (CaCl₂, ZnCl₂, MgSO₄, AlCl₃, FeCl₃, K₂FeO₄) and acids (H₃PO₄, H₂SO₄, HNO₃) revealed significantly increased adsorption capacities, as predicted by the linear mixed-effects model. The adsorption capacity of biochar prepared from biomass modified with 1 M H₂SO₄ for 24 h and pyrolysed at 700 °C can reach 637.71 mg/g, and the biochar exhibits enhanced adsorption capacity compared with those previously reported. Results of this study demonstrate the feasibility and accuracy of using meta-analysis to predict the performance of biochar in the efficient adsorption of tetracycline from water and provide a robust scientific framework for customised biochar preparation with specific functions.