Developing a Functional Geopolymer Foam Composite from Natural Fibers and Kaolinitic Soil from Al-Kharj and Exploring Its Application in Water Treatment

In recent decades, researchers have developed innovative compositions and methods to fabricate geopolymers and enhance their properties for diverse multifunctional applications. Geopolymer foams are regarded as promising functional materials across numerous disciplines; however, they face challenges such as brittleness and limited mechanical strength. This investigation aims to produce a geopolymer foam composite by incorporating three-dimensional (3D) Luffa Cylindrical Fibers (LCF) into a metakaolin-wollastonite geopolymer matrix. The composites were synthesized using an alkaline activator, mineral powders (wollastonite and metakaolin), a foaming agent (aluminum powder), and a foam stabilizer (olive oil). Their mechanical characteristics and capacity for Cu and As ion adsorption were examined, with structural analyses supplemented by scanning electron microscopy (SEM) and optical microscopy. Reinforcing with LCF markedly improved mechanical performance: flexural strength increased from 0.27 MPa to 0.60 MPa, while compressive strength rose from 0.04 MPa to 0.34 MPa. In addition to the amorphous structure, two new crystalline phases were detected: analcime and anorthite in the GLF matrix. The geopolymer foam composite (GLF) exhibited adsorption capacities of 4.6 mg/g for Cu, 5.18 mg/g for As, and 5.09 mg/g for methylene blue (MB) dye. The equilibrium adsorption capacity (qe) for Cu ions varies with the GLF mass, with smaller GLF masses yielding higher qe. Specifically, qe increases from 2.1 mg/g to 12 mg/g as the GLF mass decreases from 2 g to 0.25 g. Visual assessments reveal enhanced dye adsorption following LCF incorporation. Its high efficacy in removing Cu ions and metal-uptake capacity underscores its potential for practical water-treatment applications, offering sustainable solutions for environmental management.