Ahmed A. Ahmed

Synthetic dyes found in wastewater create substantial environmental hazards and health risks, which require effective and sustainable wastewater treatment methods. This study investigates the use of Cyperus Rotundus as a natural adsorbent to remove methyl orange in aqueous solutions under a batch system. A total of 71 experimental runs were conducted to examine the effects of initial dye concentration (5–100 ppm), pH (3–11), contact time (10–90 min), and temperature (25–45°C) on the adsorption process. The maximum removal efficiency of 97% was obtained at a dye concentration of 10 ppm, pH of 4, and contact time of 90. Isotherm analysis revealed that the Langmuir model can provide the best fit with a maximum adsorption capacity of 2.25 mg/g, and a coefficient of determination (R2 = 0.657) while kinetic data followed the pseudo-second-order model indicating that chemisorption is the dominant mechanism (R2 > 0.95). Thermodynamic analysis proved that this adsorption is both spontaneous (with a standard Gibbs free energy change ranging from ΔGo = - 4.76 to -5.69 kJ/mol) and endothermic (enthalpy change ΔH° = 9.10 kJ/mol). Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR) were used to confirm the presence of dye adsorbent interactions by testing structural and functional changes of the groups that occurred after adsorption. The results show that Cyperus Rotundus is a low-cost biosorbent in methyl orange removal and can serve as a sustainable wastewater treatment material.

This research presents a new biocomposite adsorbents using response surface methodology (RSM) to find the best conditions for highest adsorption of Brilliant Blue G250 (BBG) from aqueous solution by Amberlite XAD-4/Agaricus campestris. The most effective parameters are determined by Plackett–Burman design (PBD) with specific ranges initial dye concentration (5–150 mg.L-1), temperature (20–50°C), contact time (5–100 min), pH (3–11), shaking speed (150–300 rpm), sample volume (5–75 mL), and adsorbent dosage (0.05–0.6 g). Then, in the second step, the optimum condition of effective factors is predicted using steepest ascent design. Finally, optimal medium conditions of effective parameters with central composite design are located. According to RSM, the best adsorbent amount, contact time, initial dye concentration, and sample volume for maximum removal% of BBG (96.72%) are 0.38 g, 60.78 min, 107.13 mg.L-1, and 28.6 mL, respectively. The adsorption of brilliant blue is approved by scanning electron microscopy. Under optimum conditions, it is concluded that XAD4/A. campestr is biocomposite is a suitable adsorbent for removing BBG from aqueous solution.