Bandara, P.M.C.J.Balasooriya, N.W.B.Weerasooriya, R.2025-11-122025-11-122022-10-28Proceedings of the Postgraduate Institute of Science Research Congress (RESCON) -2022, University of Peradeniya, P 23978-955-8787-09-0https://ir.lib.pdn.ac.lk/handle/20.500.14444/6544Drinking water treatment using sand filters has a long history in water purification plants, and it is one of the most energy-intensive components. Sand filters have many variants, such as rapid sand filters, etc., to enhance their efficiency. The majority of sand filters are used to trap suspended solids and colloid particles in the water. In the present study, the sand granules are modified to improve their efficiency by simultaneously removing fluoride and turbidity. The sand particles were chemically modified using iron oxide in the presence or absence of graphene oxide (labeled as Fe₂O₃-S for Fe₂O₃ coated sand, or Fe₂O₃- GOS for Fe₂O₃ and graphene oxide coated sand) mimicking the natural sand coating processes that occur in the environment. The graphene oxide (GO) was synthesized using Sri Lankan vein graphite as a starting material. The surface properties of sand composites were characterized by IR spectroscopy, X-ray diffraction, and surface titration methods conducted to probe their sites’ reactivity. According to the surface titration data, the pHzpc was at 6.30 for GOS, Fe₂O₃-S, and Fe₂O₃-GOS surface titration are in progress. Compared to Fe₂O₃-S, GOS and Fe₂O₃-GOS showed enhanced stability in water. The fluoride removal efficiency of sand, Fe₂O₃-S, GOS, and Fe₂O₃-GOS were 4.3, 17.0, 69.0, and 73.0%, respectively, at 2 mg l -1 initial fluoride loading. In the presence of bare sand, the water turbidity values increased from 0.85 to 1.04 NTU due to the presence of negatively charged colloids. However, when sand was chemically modified, the turbidity was decreased by 60% in Fe₂O₃-S, 90% in GOS, and 96% in Fe₂O₃-GOS (from 0.85 NTU to 0.34 NTU, 0.08 NTU, and 0.03 NTU). Our data suggested that the Fe₂O3-GOS is the most stable for excess fluoride and turbidity removal in water. All these experiments were conducted in batch mode, and column mode experiments are in progress for reactor designs.en-USCoated sandFluorideGraphene oxideSand filtersTurbidityArticle