Study on Wastewater Treatment in the Textile Industry by Adsorption of Reactive Red 141 Dye Using a Phosphogypsum/Vanadium Composite Developed from Phosphate Industry Waste

A novel method has been explored based on the recovery of two industrial wastes V 2 O 5 and phosphogypsum from the fertilizer production industry, which also provide a significant challenge due to their toxicity and environmen - tal impact. To solve the problem of these two harmful wastes, these residues have been transformed into valuable resources, by the elaboration of Nanoparticles vanadate-hydroxyapatite (NPs-HAP/VAP) adsorbent, contributing a sustainable solution without requiring expensive or highly skilled work. This comprehensive investigation ex - plores the adsorption of the reactive red 141 dye (RR 141) on Ca 10 (VO 4 ) x (PO 4 ) 6−x (OH) 2 , with (x i = 0, 1.5, 3, 4.5, and 6). Using a Centered composite design (CCD), several parameters influencing the adsorption process were examined. The optimal adsorption capacity is 50 mg. g – 1 under optimal conditions 57.5 mg of the adsorbent dose, 152.5 mgL -1 for the RR 141, pH 8, 92.5 minutes of contact time, and incorporation ratio of 4.5 with an R 2 of 0.99. These results reinforce the effectiveness of our chosen CCD model. Kinetic analysis demonstrated a pseudo-order reaction model with an R 2 ˃ 0.92, while the Sips isotherm describes the adsorption process. Thermodynamic studies revealed spontaneous adsorption, suggesting a physical character enhanced by a positive entropy variation.