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A straightforward approach to recycle waste expanded polystyrene (EPS) foam to produce polystyrene (PS) microfibers using the improvised centrifugal spinning technique is demonstrated in this work. A typical benchtop centrifuge was improvised and used as a centrifugal spinning device. The obtained PS microfibers were characterized for their potential application for oil adsorption. Fourier transform infrared spectroscopy results revealed similarity on the transmission bands of EPS foam and PS microfibers suggesting the preservation of the EPS foam’s chemical composition after the centrifugal spinning process. Scanning electron microscopy displayed well-defined fibers with an average diameter of 3.14 ± 0.59 μm. At the same time, energy dispersive X-ray spectroscopy revealed the presence of carbon and oxygen as the primary components of the fibers. Contact angle (θCA) measurements showed the more enhanced hydrophobicity of the PS microfiber (θCA = 100.2 ± 1.3°) compared to the untreated EPS foam (θCA = 92.9 ± 3.5°). The PS microfiber also displayed better oleophilicity compared to EPS foam. Finally, the fabricated PS microfibers demonstrated promising potential for oil removal in water with a calculated sorption capacity value of about 15.5 g/g even at a very short contact time. The fabricated PS fiber from the waste EPS foam may provide valuable insights into the valorization of polymeric waste materials for environmental and other related applications.

In this study, a versatile sensing platform based on a commercially available filter paper for the development of a colorimetric sensor using label-free gold nanoparticles (AuNPs) for the detection of cyanide in water is presented. The developed sensor can be applied for the direct detection of cyanide from an aqueous sample efficiently in a wide concentration range. The synthesised AuNPs were found to have an average size of about 13.2 ± 2.65 nm with a surface plasmon resonance peak at around 525 nm. Successful integration of AuNPs on the WFP substrate was observed through the FESEM-EDX analysis and supported by the presence of an absorbance peak at about 528 nm on the spectrum of the WFP-AuNPs composite. The colour of the WFP-AuNPs composite changed from purple-red to white in the presence of cyanide. Using the paper-based sensor, the limit of detection is calculated to be 7.68 × 10−6 M (0.5 ppm). The said sensitivity is good enough for the determination of cyanide in industrial wastewater samples. The developed sensor also showed excellent selectivity towards cyanide over other ions, demonstrating its practical applicability to monitor cyanide contamination in different environmental samples. Furthermore, the applicability of the sensor was demonstrated using several real water samples spiked with cyanide, including creek and tap water. Notably, the sensor showed great promise for the rapid, cost-effective, and versatile monitoring of cyanide contamination in various aqueous samples.