Design of an efficient, tunable and scalable freestanding flexible membrane for filter application

Abstract

Severe impacts of water contamination on the environment and human health have compelled us to study and design an efficient and reusable filter with tunable pore size.

Thermally Stable, Thin, Ultralight, Reusable, and Flexible Multiwalled Carbon Nanotube Membranes for Removal of Heavy Metals, Polycyclic Aromatic Hydrocarbons, and Particulates from Coal Smoke

“…As a result, because most membranes are subjected to stress and deformation during processing and use, it is vital to analyze membrane mechanical properties in settings that are comparable to actual loading conditions. As shown in Figure j, the tensile strength of the designed MWCNT membranes has often been found to be around ∼0.56 MPa, indicating that the membrane is mechanically strong enough for air filtration duties. , Moisture-containing air pollutants reduce the filtration efficiency of commercial HEPA filters due to membrane fouling, and they do not possess a self-cleaning concept. So, keeping that in mind, we have designed a self-cleaning hydrophobic (contact angle of 138° ± 6°) MWCNT membrane as compared to a hydrophilic HEPA filter (contact angle of 80° ± 4°), shown in Figure k.…”

“…In addition, HEPA (High-Efficiency Particulate Air) filters are designed to remove particles larger than approximately 300 nm (such as dust, pollen, pet dander, and other large airborne particles) with high efficiency due to size-based exclusion. , Thereafter, the pore size of multiwalled carbon nanotube (MWCNT) membranes is much smaller than that of HEPA filters, allowing the selective filtration of nanoparticles, molecules, or ions at the nanoscale level. This property is beneficial for applications where precise control over the size and separation of particles is required, such as nanofiltration and molecular separation. − …”

“…29−32 The MWCNT-based membrane developed through a vacuum-filtration assisted technique has been used for pollutant filtration by utilizing the superior physical properties of MWCNTs such as high aspect ratio, large surface area, high thermal stability, hydrophobicity, narrow pores, high porosity, high packing density, and interconnected open tubular networks. 30 In addition, several attempts have also been made to lower the toxicity of air using granular activated carbon, 33 zeolite, 34 Zr-MOFs, 35 fabric filters (FFs), 36 electrostatic precipitator (ESP), 8 Ce/Mo doping catalyst membrane, 37 SiO 2 −TiO 2 nanofibers, 38 MnO 2 −HC filter, 39 polyimide (PI) nanofiber, 40 and TiO 2 nanotube, 41 but their irregular and variable pore size, microsize fiber, low thermal stability, thickness, hydrophilic nature, reusability, and flexibility are disadvantageous for air filtration and add other pollutants to the air. Thus, we believe that MWCNT membrane-based filters might be a viable alternative for removing PM, PAHs, and HM from the air.…”

Multiwalled Carbon Nanotube-Based Freestanding Filters for Efficient Removal of Fine Particulate Matters (PM0.3), Microplastics (MP0.3), and Bioaerosols

“…As a result, a research article published earlier by our group possessed MWCNT membranes with the tensile strength of functionalized MWCNT membranes (FMWCNTs) where the MWCNT membrane has a tensile strength of ∼18.3 MPa while the FMWCNT membrane has a tensile strength of ∼6 MPa. In the present study, we have used the same pristine MWCNT membrane having a tensile strength of ∼18.3 MPa for air filter application …”

“…In the present study, we have used the same pristine MWCNT membrane having a tensile strength of ∼18.3 MPa for air filter application. 51 In the PM and MP filtration experiments, we use the air filtration setup to investigate the filtration efficiency of the MWCNT membrane. Highly polluted air with a high concentration of particulate matter (PM) (size 0.3−2.1 μm) was generated by burning coal dust in the furnace, which was then pushed by compressed air and smoke stored in the gas chamber joined with OPS, and smoke was also collected in a gas impinger for further characterization of the sample for 45 min.…”