High efficiency filter: Cellulose-derived biochar fibril and magnesium oxide composite for boosting performance of heavy metal ions capture

The safe disposal of industrial and domestic sewage without bringing secondary pollution remains tremendously challenging. In order to effectively extract and dispose off heavy metal ions (HMIs), a practically applicable biochar fibril-magnesium oxide (BCF@MgO) filter has been designed and analyzed. The various characteriza-tions have been carried out to provide a deep insight into the composite properties. It is found that the cubic MgO flakes with the size about 200 nm are coated on highly-graphitized BCF as evidenced by XRD, SEM and Raman. Abundant crevices on MgO enlarge the composite specific surface area to 201.4 m2 g-1. The unique micro-structure endows the composite with remarkable removal performance: the up-taken capacities towards Cd2+ and Pb2+ reach 2035.4 and 3410.1 mg g-1, respectively. When treating a system that two HMIs co-exist, the removal efficiency still maintains almost 100%. The recovered Cd2+/Pb2+ ions are adsorbed on BCF, which makes the spent filter be easily taken out and eliminates the secondary pollution. Besides handling the complicated water treatment situation, our material is capable of cleaning up the polluted water to the drinkable water by simple and convenient filtering. The processes of gathering, depositing and immobilizing Cd2+/Pb2+ have further been elucidated by DFT calculations.

Automated summary

A biochar fibril-magnesium oxide filter has been designed for the effective removal of heavy metal ions from industrial and domestic sewage. The filter's unique micro-structure and abundant crevices enable high removal efficiency. It is also capable of treating complicated water treatment situations and purifying polluted water into drinking water.