Synthesis and application of ZIF-08 supported on Theobroma Cacao L. biochar for the adsorption of loratadine in aqueous media

Drugs can be eliminated from the body through two primary mechanisms: metabolization or direct release. This process is dependent on the water solubility of the drug and the type of metabolite generated. The release of unmetabolized drugs has led to a significant environmental impact due to the complex interactions of these compounds with wastewater, leading to their classification as emerging pollutants in ecosystems. To address this issue, we developed a composite material called ZIF-08@BC. This composite is based on cocoa shell biochar (BC) obtained through microwave-assisted pyrolysis, which was then impregnated with an imidazole zeolite-type metal-organic fragment (ZIF-08). The resulting composite material was extensively characterized using various analytical techniques, including TGA, XRD, BET, pH_PZC, and FTIR. The adsorption capacity of the ZIF-08@BC composite was evaluated using the drug loratadine as a model compound. The results showed that the best adsorption process conditions were an adsorbent dose of 0.07 mg/L, pH 6, an initial concentration of 40 mg/L, and a contact time of 40 minutes. Under these conditions, the composite achieved a maximum adsorption capacity of 21.041 mg/g. The adsorption process was found to best fit a pseudo-first-order kinetic model (R² = 0.966, q_e (calc) = 22.46 mg/g, and E = 0.009) and an isothermal Slip model (R² = 0.997 and ks = 0.182). In conclusion, the ZIF-08@BC composite has proven to be an effective adsorbent for the treatment of aqueous media contaminated with the drug loratadine. This composite material represents a promising alternative for mitigating the presence of this emerging contaminant in the environment.