biostudies-literatureLin LMOST | National Key Research and Development Program of China (NKPs)MOST | National Key Research and Development Program of ChinaMOST | National Natural Science Foundation of China (NSFC)MOST | National Natural Science Foundation of Chinae2501354122https://www.ebi.ac.uk/biostudies/studies/S-EPMC11962437biostudies-literatureUnknown122(12)The co-occurrence of arsenic and uranium in groundwater has been found in many countries, posing a significant challenge to human health. Here, we have demonstrated the efficient simultaneous removal of arsenic and uranyl-carbonate complexes from groundwater using {001}-TiO₂. Surprisingly, the presence of U(VI) greatly enhanced the adsorption of As(V) on {001}-TiO₂, while As(V) had a negligible impact on U(VI) adsorption. Through in situ ATR-FTIR spectroscopy, we uncovered a mechanism involving the formation of a ternary surface complex [Ti-U(VI)-As(V)] on the surface of {001}-TiO₂. This ternary surface complex formed through the substitution of CO₃^2- from uranyl coordination sites. Furthermore, the adsorbed As(V) and U(VI) can be easiProceedings of the National Academy of Sciences of the United States of AmericaTernary surface complexation promotes simultaneous removal of arsenic and uranium by TiO<sub>2</sub>.PMC1196243751678557 and 419772802023YFC3207902Luan FLi ZRen JLin LMeng YfalseTernary surface complexation promotes simultaneous removal of arsenic and uranium by TiO<sub>2</sub>.The co-occurrence of arsenic and uranium in groundwater has been found in many countries, posing a significant challenge to human health. Here, we have demonstrated the efficient simultaneous removal of arsenic and uranyl-carbonate complexes from groundwater using {001}-TiO₂. Surprisingly, the presence of U(VI) greatly enhanced the adsorption of As(V) on {001}-TiO₂, while As(V) had a negligible impact on U(VI) adsorption. Through in situ ATR-FTIR spectroscopy, we uncovered a mechanism involving the formation of a ternary surface complex [Ti-U(VI)-As(V)] on the surface of {001}-TiO₂. This ternary surface complex formed through the substitution of CO₃^2- from uranyl coordination sites. Furthermore, the adsorbed As(V) and U(VI) can be easi2025-01-01T00:00:00Z2025 Mar2026-06-03T12:10:31.371Z2026-04-27T03:11:28.598ZS-EPMC119624374011210410.1073/pnas.2501354122