Waste-to-resource valorization of babassu biomass: biochar integrated with ceramic microfiltration for oily water treatment

Abstract Produced water from oil production contains high levels of suspended solids, hydrocarbons, and salts, requiring efficient treatment before reuse or discharge. This study proposes a hybrid system integrating adsorption using babassu coconut biochar with ceramic microfiltration to treat real produced water from the Rabo Branco field in Brazil. A comprehensive characterization was performed for both the biochar (surface area, pore volume, TGA, SEM, FTIR, elemental composition, and true density) and the produced water (oil and grease, turbidity, total solids, pH, conductivity, and salinity) before and after treatment. The biochar exhibited a high specific surface area (304.79 m 2 /g) and a micro–mesoporous structure (pore volume: 0.18 cm 3 /g; average pore size: 1.88 nm). Powdered biochar reduced oil and grease content (OGC) from 429.8 to 9.8 mg/L, enabling stable membrane performance with permeate fluxes of 210–220 L/m 2 h. Across three real produced water samples, turbidity removal reached 99.88–99.99%, with final values between 0.02 and 0.6 NTU. OGC removal reached 100%. Total solids decreased by 10–13%, while conductivity and salinity declined by 9–12%. These results demonstrate the high efficiency of the system, strong fouling control and high reproducibility. The novelty of this study lies in the use of babassu biochar in a continuous-flow hybrid system, an approach that appears to be scarcely explored in the literature. The system offers a low-cost, scalable, and sustainable solution for produced water treatment, with potential for industrial application. By valorizing agro-industrial residues and enhancing effluent reuse, this approach supports environmental protection and aligns with the United Nations Sustainable Development Goals (SDGs).