Highly electrostatic cellulose acetate materials assisted by copper ion coordination for air filtration

Petroleum-based electret air filtration materials can capture particulate matter efficiently by electrostatic adsorption, but the non-degradation of such materials causes environmental pollution. Cellulose acetate (CA) is an environmentally friendly filtration material with great application potential. However, its polyhydroxyl structure and weak polarization make it difficult to construct high electrostatic, which is not conducive to filtration. Here, we report a molecular chain spacing expansion strategy for achieving high-performance cellulose-based electrospun materials for air filtration by coordination with copper ion (Cu²⁺). Through the coordination we show that the restriction of CA hydrogen bonding network for its dipole orientation polarization under the external electric field (independent polarization properties) is weakened, i.e., its dipole moment was greatly improved from 5.23 debye to 8.86 debye. Due to its high surface potential (7.97 kV), the Cu²⁺-coordinated CA film exhibits excellent filtration performance with a high PM 0.3 removal efficiency of 99.15 % and a low pressure drop of 37.3 Pa, which is 39.98 % higher than that of the pure CA film. Moreover, by comparing the filtration performance of particles with different sizes (PM 0.3, PM 0.5, PM 1.0), it is found that the electrostatic adsorption works better for smaller particles.