Magnetic biochar conjugated quaternary ammonium salt-constructed hemoperfusion adsorbent for viral removal with rapid and high-performance

[Display omitted] •A magnetic biochar conjugated quaternary ammonium salt (Fe3O4/C-2) was successfully constructed using the one-pot HTC method.•The Fe3O4/C-2 presented high removal rate of over 99.99 % toward virus within 45 min, which corresponds to a decrease in the infectious HIV titer by approximately 104 times.•Electrostatic interactions greatly contribute to the adsorption of viruses.•The Fe3O4/C-2 show good anticoagulant activity and magnetic separation performance.•The adsorbent is cost-effective and eco-friendly can be used for viral diseases treatment. Due to variations in virus structures and their high variability, treating viral infections remains challenging. Moreover, developing vaccines and medications for newly emerged viruses demands a significant time investment. Efficient methods are required to prevent dangerous infections caused by unknown pathogens. Hemoperfusion, with its low cost, can effectively remove toxins from the blood quickly, thus achieving therapeutic effects. The core of the hemoperfusion technology lies in the adsorbent. Therefore, the development of a viral adsorbent aiming to combat viruses through hemoperfusion was envisioned, following general principles to effectively save lives and buy time for the research and development of vaccines and medications. Towards this goal, a facile, green, and low-priced magnetic biochar/quaternary ammonium salt (Fe3O4/C-2) was constructed using the hydrothermal carbonization (HTC) method. HIV lentiviruses were used as a model pathogen to quantify the adsorption capacity and elucidate the adsorption mechanism. Benefiting from a macroporous structure and electrostatic interactions, fabricated Fe3O4/C-2 has a high adsorption capacity (965 ng g−1) and strong suppression of infectious activity (99.99%). Moreover, a low hemolysis ratio (100%), high activated partial thromboplastin time (APTT) (67.29 s), and low protein adsorption (