Organic-Inorganic hybrid membrane for simultaneous heavy metal removal at drinking water pollution concentration levels

This study proposes a novel approach for simultaneous removal of potentially toxic metals from contaminated drinking water. The strategy is based on multi-layer graphene oxide hybrid membranes made up of Fe3O4@amyloid fibrils nanoclusters intercalated into the graphene oxide sheets via flow through approach. The hybrid membrane outperforms the previously known graphene-based membranes with adsorption capacity in the range of 128–570 mg g−1 of material. The membrane's removal efficacy exceeds 99.9% in both low (150 µg/L) and high (10,000 µg/L) metal concentration regimes, representative of ground water and wastewater contamination and complies with WHO drinking water requirements. Following NSF/ANSI 42,53–2007a American Standard Regulations, samples with metal concentrations of 150 µg/L and 20 mg L−1 calcium coexisted at pH 6.5 ± 0.25, complete removal of heavy metals (100%) in the effluent was observed. Benchmark testing on real municipal and ground water samples in continuous operation mode shows that ∼ 7500 and 5000 L water/g of membrane were treated well while maintaining WHO drinking water standards. The saturated membrane regenerated and successfully reused several times without losing purification performance. The present technique shows a great deal for addressing the worldwide problem of contaminated drinking water due to good selectivity, low fabrication cost, and excellent performance on real water.