Utilizing Pyracantha coccinea L. for dye adsorption in industrial wastewater treatment

In this study, color removal from industrial wastewater was achieved using pure, and dimethylglyoxime-modified Pyracantha coccinea L. fruits for adsorption. Maxilon yellow 4GL dye was used to represent the color-forming parameters in industrial wastewater. The optimal pH values for pure and modified biosorbents were 8 and 12, respectively. The decoloration analyses were conducted at different temperatures (5, 15, 30, and 45 °C) and biosorbent amounts (0.1, 0.2, 0.4, 0.6, 0.8, and 1 g). Scanning electron microscopy, Fourier-transform infrared spectrophotometry, and zeta potential analyses were performed to determine the structures of the biosorbents. Based on these analyses, the optimal amount of both biosorbents was determined to be 0.1 g. The highest color removal rates for the pure and modified adsorbents were obtained at 45 °C (77.22%) and 30 °C (74.14%). In the Langmuir isotherm model, the R_L values of the pure and modified adsorbents were determined at all temperatures (0 < R_L < 1). According to the n values of the Freundlich isotherm, the adsorption mechanism was physical. The homogeneity of the modified adsorbent surface increased at 5, 15, and 30 °C. Thermodynamic analysis revealed that the process was exothermic (ΔH < 0). FTIR results showed that C-N, N–O, and M–O bonds were formed when the pure biosorbent was modified, but the O–H and C-H bonds were lost. SEM analysis showed that the modification increased the number and diameter of the biosorbents and adsorption capacity. According to the zeta potential results, the surface charges of the biosorbents are similar.