Electrospun nanofiber mats have emerged as promising materials for water purification applications, particularly in the removal of particulate matter and pathogens. Polymers such as polyacrylonitrile (PAN) and polyvinylidene fluoride (PVDF) are commonly used due to their mechanical stability, chemical resistance, and tunable fiber morphology. These mats exhibit high surface area-to-volume ratios and interconnected porous structures, enabling efficient filtration while maintaining low pressure drops. The performance of electrospun nanofiber mats in water filtration depends on several critical factors, including fiber diameter, mat porosity, and strategies to mitigate fouling. Comparisons with commercial microfiltration membranes highlight the advantages and limitations of nanofiber-based systems.

Fiber diameter is a key parameter influencing the filtration efficiency of electrospun mats. Studies have demonstrated that reducing fiber diameter enhances the capture of smaller particles due to increased surface area and reduced pore sizes. For instance, PAN nanofibers with diameters ranging from 100 to 500 nm have shown filtration efficiencies exceeding 95% for particles larger than 0.3 µm. The diameter can be controlled by adjusting electrospinning parameters such as polymer concentration, applied voltage, and feed rate. Lower polymer concentrations and higher voltages generally produce thinner fibers, though excessive thinning may compromise mechanical integrity. PVDF nanofibers, known for their hydrophobicity and chemical stability, exhibit similar trends, with optimal diameters for water filtration applications falling between 200 and 600 nm.

Porosity and pore size distribution are equally critical in determining the performance of nanofiber mats. The interconnected pores in electrospun mats typically range from 0.1 to 10 µm, making them suitable for microfiltration applications. Unlike conventional membranes with uniform pore structures, nanofiber mats possess a gradient porosity that enhances particle capture through depth filtration. This structure allows for higher dirt-holding capacity compared to surface-filtering commercial membranes. Research indicates that mats with porosity levels of 70–90% achieve balanced performance, combining high permeability with adequate particle retention. For example, PVDF nanofiber mats with 80% porosity have demonstrated water fluxes of 500–800 L/m²·h at operating pressures below 1 bar, outperforming many polymeric microfiltration membranes in terms of throughput.

Fouling mitigation remains a significant challenge in nanofiber-based filtration systems. Organic and biological foulants can clog pores and reduce flux over time. Surface modification techniques, such as grafting hydrophilic polymers or incorporating antimicrobial agents, have been explored to address this issue. PAN nanofibers functionalized with zwitterionic polymers exhibit reduced protein adsorption and bacterial adhesion, extending operational lifespans. Similarly, PVDF mats blended with silver nanoparticles show enhanced antifouling properties due to the biocidal effects of silver ions. These modifications often come with trade-offs; for instance, hydrophilic coatings may improve fouling resistance but could weaken mechanical strength. Comparative studies suggest that electrospun mats with tailored surface chemistry can rival commercial membranes in fouling resistance while offering easier cleaning and regeneration.

Commercial microfiltration membranes, typically made from materials like polyethersulfone (PES) or polyvinylidene fluoride (PVDF), are widely used in water treatment due to their consistent quality and scalability. However, they often suffer from high manufacturing costs and limited porosity. Electrospun nanofiber mats present a cost-effective alternative with higher porosity and customizable pore structures. In terms of particle removal efficiency, nanofiber mats can match or exceed commercial membranes, particularly for submicron particles. For pathogen removal, both systems achieve high log reduction values (LRVs) for bacteria (e.g., >6 LRV for E. coli), but nanofiber mats may require additional functionalization to achieve comparable virus retention.

Mechanical durability is another area where electrospun mats are often compared to commercial membranes. While traditional membranes exhibit higher tensile strength due to their dense structures, nanofiber mats can be reinforced through crosslinking or support layers. For instance, PAN nanofibers electrospun onto a polyester nonwoven scaffold show improved handling and longevity without significant flux reduction. Long-term studies indicate that properly engineered nanofiber mats can withstand continuous operation for several months, though further optimization is needed to match the lifespan of industrial-grade membranes.

Environmental considerations also favor electrospun nanofiber mats in some cases. The energy consumption during electrospinning is generally lower than that of phase inversion processes used for conventional membranes. Additionally, certain nanofiber polymers, such as PAN, can be recycled or incinerated with lower toxic emissions compared to halogenated membrane materials. However, the environmental impact of nanoparticle additives or surface treatments must be carefully evaluated to ensure sustainability.

In summary, electrospun nanofiber mats based on PAN or PVDF offer distinct advantages for particulate and pathogen removal in water purification. Their tunable fiber diameters and porous structures enable high filtration efficiency and flux rates, while surface modifications can mitigate fouling. Compared to commercial microfiltration membranes, nanofiber mats provide cost and performance benefits but require further development in mechanical robustness and scalability. Future research should focus on optimizing material combinations and fabrication techniques to bridge the gap between laboratory-scale success and industrial adoption. The potential for integrating these mats into modular or disposable filtration systems could further enhance their practicality for diverse water treatment scenarios.