Edi Nasra, Deswati, Safni, Yulia Eka Putri, M. Iqbal Saputra Gemasih, Adewirli Putra
Silica xerogel derived from fly ash was synthesized and subsequently functionalized with ethylenediamine (EDA) and cupric ions (Cu2+) to produce a renewable hybrid adsorbent (SiO2@NH2-Cu) aimed at enhancing heavy metal removal from aqueous systems. The integrated process - comprising acid leaching, alkaline extraction, sol-gel gelation, and sequential organic/metal functionalization - successfully transformed crystalline fly ash into a high-purity amorphous silica framework. Acid activation increased the SiO2 content from 32.867 to 46.016 mg/kg, while the final xerogel achieved 71.053 mg/kg, confirming efficient impurity removal and silica enrichment. Fourier transform infrared (FTIR) analysis verified the incorporation of -NH2 and -CH2 groups, while energy dispersive X-ray spectroscopy (EDS) revealed 0.46 wt% Cu, indicating effective metal anchoring onto the amine-functionalized silica surface. Textural analysis showed a mesoporous architecture with a surface area of 77.42 m2/g, a pore volume of 0.3894 cm3/g, and an average pore diameter of 16.09 nm, demonstrating substantial pore expansion following functionalization. Field emission scanning electron microscopy (FESEM) imaging further revealed uniform morphology and homogeneous Cu distribution. An artificial neural network (ANN) model was developed to predict adsorption performance based on structural and surface chemistry parameters, including pore size, -NH2 group density, and Cu loading. Sensitivity analysis confirmed these parameters as the dominant contributors to adsorption efficiency. The combined experimental-computational approach highlights the synergistic role of EDA and Cu2+ in enhancing surface reactivity, establishing SiO2@NH2-Cu as a promising low-cost, sustainable adsorbent for wastewater treatment and related environmental applications. © (2026), (Polskie Towarzystwo Inzynierii Ekologicznej (PTIE)). All right reserved.
Department of Chemistry, Faculty of Mathematics Natural Sciences, Andalas University, Padang, Indonesia; Department of Chemistry, Faculty of Mathematics Sciences, Universitas Negeri Padang, Padang, Indonesia; Department of Medical Laboratory Technology, Syedza Saintika University, Padang, Indonesia
