Polyacrylonitrile (PAN) and Polyamide (PA)-6 based nanofibrous composite were prepared for air filtration application. PAN was electrospun on spun-bonded non-woven polypropylene which acts as a collector and the samples were coated with PA-6. Box-Behnken experimental design was used to design the experimental plan. As per the experimental plan, PA-6 coated samples were treated with different concentrations of an alkali solution (NaOH) (2%, 5% and 8%) and treatment temperature (60oC, 80oC and 100oC) to enhance the surface properties. As prepared nanofibrous composite was tested for its various properties such as surface morphology, particle filtration efficiency and air permeability. Fourier transform infra-red analysis and scanning electron microscope were performed to analyze the functional groups and morphology of the nanofibrous composite respectively. The air permeability of the control and treated samples was analyzed as per the standard procedure and the permeation level varies from 52.5 to 60 cm3/cm2/s for control samples, 65–195 cm3/cm2/s for treated samples. The overall filtration efficiency for treated samples varies from 36.54% to 78.56%. The sample which is treated with 5% NaOH at 60oC has a higher overall filtration efficiency of 78.56%.

Filtration of Particulate Matter (PM) 2.5 and PM 10 particles are focused by the filters used in Heating, Ventilation and Air Conditioning (HVAC) systems. Synthetic fibres/filaments are widely used to construct the filters for air conditioning filters and cleanroom filters which is not biodegradable. Natural fibres are easily biodegradable, exhibit better filtration characteristics as like synthetic fibres. In this research, alkali-treated coir fibres are used to construct the filter for filtering the particle range of 1.0 µm to 10 µm. Box- Behnken experimental design was used for the experimental plan and the experiments were conducted to construct the filters. The change in fibre properties by alkali-treatment was observed and the treatment with 5% and 10% alkali increases the crystallinity index of fibres. The influence of independent variables on the performance of developed filters was analyzed in detail. 5% NaOH treated fibre sample with 20% resin proportion and 60 g fibre content in the unit area was identified by a quality factor as the best combination of independent variables for constructing filter.