Flow-Driven Deformable Filter Enables Ultimate As(III) Control by Enhancing the Mass Transport of the Adsorbate to Highly Dispersed Active Sites

Abstract

The development of decentralized household filters is one of the most feasible solutions for treating As(III)-contaminated groundwater worldwide. To avoid the health risks caused by premature breakthroughs, it is vital to design a robust filter to intensify the effective contact between active sites and trace As(III). Herein, we have developed a filter filled with a flexible adsorbent that can continuously change its configuration under the shear force of a flowing fluid to actively enhance mass transport, wherein bimetallic Fe/Zr nanoparticles were encapsulated in a deformable graphene hydrogel to serve as active sites. The corresponding characterization revealed that the nanoparticles were highly dispersed in confined spaces composed of graphene nanosheets, enabling a 2.3-fold increase in the adsorption kinetics. Numerical simulations verified that its deformability reduced the hydrodynamic dead volume, resulting in a 43.6% increase in the mass transfer efficiency. Based on the above advantages, a homemade filtration column ensured an ultra-low As(III) concentrations (0.2 μg L–1) in effluent from an influent containing 200.0 μg L–1 As(III), and the total treatment volume reaches up to 3198.4 BV (bed volume). Overall, this flexible adsorbent-based filter enabled quick and ultimate As(III) control for households exposed to As(III) contamination.