Goethite modified expanded vermiculite adsorbent for As(V) and Rhodamine B removal: Sustainable technologies development for waste materials disposal

Expanded vermiculite (EVer) was acid-activated, silanized, and subsequently modified with iron oxyhydroxide (goethite), resulting in the EVa-G adsorbent. Batch experiments demonstrated EVa-G?s high adsorption efficiency for arsenate As(V) and Rhodamine B (RB), with capacities reaching 59.31 mg g?? and 223.2 mg g??, respectively. After five adsorption/desorption cycles, the adsorbent retained high regeneration efficiencies - 88.6% for As(V) and 90.6% for RB - indicating excellent reusability. The desorbed RB solution was further treated via photocatalytic degradation (using ZnO) and arsenate stabilization, yielding environmentally safe effluents. Additionally, exhausted was EVa-G - after acidic washing and grinding (<50 ?m) was effectively repurposed as a filler in unsaturated polyester resin (UPR) composites. This significantly enhanced the flame-retardant properties of composites, especially when combined with aluminum trihydroxide (ATH). Although mechanical properties were slightly reduced, the developed multifunctional EVa-G adsorbent and associated sustainable reuse strategies represent a promising circular approach that efficiently integrates waste material recycling with environmental protection.