Aquatic arsenic removal with a Zr-MOF constructed via in situ nitroso coupling

• Novel Zr-MOF adsorbent was prepared via nitroso coupling, assembling Zr-oxo clusters. • The MOF provides ample internal space to transport and accommodate As(V) species. • The MOF shows excellent stability, adsorptive capacity and selectivity for As(V) removal. • Mechanistic study reveals respective roles of MOF clusters and linkers in adsorption. Assembly of hexanuclear Zr-oxo clusters via in situ covalent coupling of nitroso groups afforded a metal–organic framework (MOF) with fcu topology. The MOF, namely SUM-8, emerged as an excellent adsorbent for aquatic arsenic removal in terms of adsorptive efficiency, capacity, selectivity, and cyclability, on accounts of its chemical stability and structural parameters suitable for arsenate diffusion/accommodation.