The wool fabrics were treated with VOSO₄ aqueous solution and its photothermal conversion and heat retention behaviours were evaluated in comparison with the fabrics of untreated wool, normal polyester and polyester incorporated with zirconium carbide. The adsorption of vanadium ions onto the wool fabric was found to be the Langmuir type. The VOSO₄-treated wool fabric showed higher photothermal conversion than the untreated wool fabric, when it was irradiated with the visible/IR light. The temperature of the VOSO₄-treated wool single fabric under the light irradiation decreased slightly with an increase in the chamber humidity. The temperature of the single fabric after the light off increased largely with an increase in the chamber humidity. It was considered to be due to the increasing specific heat capacity of the fibre which absorbed and adsorbed water. The surface temperatures of the lighted side and of the back of the lighted side for the four-layered VOSO₄-treated wool fabrics were highest among the fabrics of untreated wool, normal polyester and polyester incorporated with zirconium carbide, when they were irradiated with the light at 65 %RH humidity. It was found that the VOSO₄-treated fabric is the warmest on the whole, when the same light is irradiated to the four kinds of layered fabrics.

A considerable amount of aramid non-woven fabrics (i.e., leftover materials, defective goods, etc.) is produced during the processing of products, leading to waste of resources as well as environmental pollution. Herein, a new strategy was proposed to fabricated multi-scale poly(m-phenylene isophthalamide) nanofiber membranes (mPMIAs) based on high-value-added application of aramid non-woven fabrics for high-temperature resistance filters. First, ultrafine PMIA nanofibers with a diameter of 17.87±8 nm (uPMIAs) and conventional PMIA nanofibers with a diameter of 112±38 nm (cPMIAs) were produced using electrospinning, and mPMIAs with different ratios of cPMIAs to uPMIAs (4:0,3:1,2:2,1:3, and 0:4) were then fabricated by adjusting the number of spin units. The results show that when the ratio of cPMIAs to uPMIAs is 2:2 (mPMIAs (2:2)), the nanofiber membrane exhibits excellent mechanical properties (fracture strength of 61.778 MPa) and thermal stability (up to 340 °C). More importantly, the mPMIAs (2:2) maintained a filtration efficiency of 98.05% for PM_0.3−10 at 300 °C. A particle vehicle exhaust filter was used to capture particles with a filtration efficiency that exceeded 97.51%. Hence, mPMIAs can potentially be utilized in high-temperature air filtration and industry filtration fields.