Impregnation of ZnO over a new hydrogel bead based conducting polymer and alginate for textile dye treatment: Interface charge transfer assessment, real wastewater treatment, and dye selectivity

In this study, we have taken a novel approach to dye removal and real wastewater treatment by employing dual smart strategies: surface charge transfer engineering and developing an easily recoverable photocatalyst. The removal of acid blue 92 (AB92) dye by using a novel 3D polypyrrole-zinc oxide-sodium alginate (PPy-ZnO-SA) nanocomposite under UV-C, visible light, and natural sunlight was investigated. The nanocomposite hydrogel was characterized using various techniques, including XRD, Raman, FESEM, TEM, XPS, PL, DRS, and CV analyses, and the type of effective interactions in different stages of removal was investigated by FTIR analysis. The optimum conditions (reaction time = 284 min, dye concentration = 19.37 mg/L, and dose of beads 36 g/L) were optimized by the central composite design (CCD) approach, and the removal efficiency of AB92 was achieved at 93.80 % and 97.16 % for UV and visible light, respectively. The nanocomposite's performance on various dyes was studied, and the catalyst successfully removed an average of 71.64 % of the cationic dyes and 95.13 % of the anionic dyes under light. After examining both photocatalytic and coagulation treatments, our analysis of actual textile wastewater revealed a COD reduction of 94.04 % and 84.62 % under UV and visible light, respectively.