Synergistic integration of Algerian Pozzolan into alginate matrix for enhanced dye removal: experimental insights and intelligent RSM/deep learning modelling

This study focuses on the use of hybrid composites as sustainable materials for removing Methylene Blue (MB) dye. Our approach involves the exploitation of low-cost hybrid alginate/Pozzolan (Alg/PZT) prepared via simple mixing, by dispersing PZT particles within the Alg matrix. The synthesised composite as well as the parent materials were characterised using powder X-ray diffraction XRD, Fourier transform infrared spectroscopy (FTIR), nitrogen adsorption–desorption and thermogravimetric analysis and its derivative TGA/DTG. Both XRD and FTIR analysis confirmed the interaction between Alg matrix and PZT, through peak shifts and structural homogenisation, as well as a reduction in crystallite size from 20.56 nm to 13.71 nm, while adsorption analysis revealed enhanced textural properties. TGA/DTG demonstrated higher thermal stability of the composite than pure Alg, affirming robust Alg–PZT interactions. The MB adsorption was carried out via a batch system. Alg/PZT exhibited a high removal efficiency reaching 95% at 160 min, adsorbent dose of 0.75 g L−1, MB solution of 20 mg L−1 and pH 9. Equilibrium data were fitted by Langmuir and Hill isotherms models, indicating predominantly monolayer adsorption on heterogeneous active sites, while kinetics followed a pseudo-second-order model, suggesting chemisorption-controlled mechanisms. The thermodynamic analysis (25-50°C) revealed the endothermic and spontaneous nature of MB adsorption with enthalpy and free energy values of 95.144 kJ mol−1 and −7.90 kJ mol−1 K−1, respectively. Furthermore, theoretical analysis, based on Response Surface Methodology (RSM) and deep learning (DL) enabled accurate prediction of removal efficiency with strong agreement between experimental and simulated results R2 = 0.996; RSME = 1.496; MAPE = 0.02), highlighting the capability of artificial intelligence tools to model complex adsorption behaviour. These findings establish the Alg/PZT biocomposite as a robust, eco-friendly and cost-effective solution for industrial wastewater treatment.