SiO2 aerogels (SAs) coating on the surface of 3D weft-knitted spacer fabrics (WKSFs) used as sorbent in oil spill cleanup

Abstract

Oily wastewater and advanced manufacturing organic pollutants are posing a serious global threat to the environment. Herein, SiO2 aerogels prepared from tetraethylorthosilicate (C8H20O4Si) by sol-gel method were coated on various 3D weft-knitted spacer fabrics (WKSFs) to study and compare the oil spill cleanup behavior in different temperatures (20 °C, 30 °C, 40 °C, 50 °C, and 60 °C), oil, and water medium. SEM and BET were used to observe the surface morphology and specific surface area of WKSFs. FTIR-ATR and XRD for the microstructure of fabrics were used to characterize the surface changes induced by the silica aerogel coating. TGA was performed to clarify the thermal degradation of WKSFs. The findings demonstrated that entirely the sorbents, particularly sorbent 2, ensured significant oil weight gain (%) and retention rate (%) in all cases. Sorbent 2 (with a weight of 350 g/m2, a thickness of 3 mm, a stitch density of 1.58/inch, a fabric density of 117 kg/m3, and a spacer yarn arrangement angle of 79.96°) showed a higher oil weight gain (%) and retention rate (%) of ((763 ± 2.31 %, 758 ± 2.08 %, and 740 ± 2.52 %) and (88.92 ± 0.87 %, 88.74 ± 0.68 %, and 85.88 ± 1.02 %)) for vegetable oil and ((698 ± 2.65 %, 693 ± 2.52 %, and 673 ± 2.65 %) and (91.18 ± 0.83 %, 90.82 ± 0.75 %, and 88.16 ± 0.90 %)) for engine oil in temperature, oil, and water medium, respectively. The statistical study revealed that coated WKSFs performed significantly at the 0.05 level (P = 0.000). The outcomes also revealed that the varieties of 3D fabric physical structures, specific surface areas, pore sizes, pore volumes, porosity ratios, water contact angles, silica aerogel add-on %, surface roughness, thermal behaviors, temperatures, and oil characteristics all played a significant effect on oil weight gain and retention capacity, especially in the oil spill cleanup performance.