Unveiling a one-minute wastewater treatment using polyacrylonitrile and polyvinyl chloride followed by smartphone-based digital image colorimetry

In this research, two one-minute wastewater treatment approaches were developed using polyacrylonitrile (PAN) and polyvinyl chloride (PVC) powders. The former process led to higher than 90% and the latter higher than 95% removal efficiencies of methylene blue from the aqueous solutions. The rapidity of the treatment process and the exhaustive removal of the pollutant are the highlights of the developed methods. The adsorbents were thoroughly characterized using scanning electron microscopy, Fourier transform infrared spectrophotometry, energy-dispersive X-ray, and Brunauer–Emmett–Teller analyses before being applied. PAN showed tiny particles piled up on each other ranging from 60 to 84 nm. The composing elements were 70.27% carbon and 29.73% nitrogen. Also, the surface area was determined to be 12.585 m² g⁻¹. On the other hand, PVC showed spherical morphology ranging from 132 to 543 nm. The elemental composition of 97.19% carbon and 2.81% chlorine was recorded for PVC. Also, the surface area of PVC was documented to be 13.302 m² g⁻¹. To conduct the procedures, the determined weights of each adsorbent were separately added into the dye-contaminated solutions and stirred on magnetic stirrers. In different time intervals, samples were taken, centrifuged to separate the adsorbent particles, and underwent colorimetric analysis. This approach dramatically reduced the analysis costs and location limitations, besides the need for no expert users. Evaluation of the isotherm models of the adsorption also revealed the preference of Freundlich and Langmuir models for PAN- and PVC-based remediation methods, respectively.