Selective, Photoenhanced Trapping/Detrapping of Arsenate Anions Using Mesoporous Blobfish Head TiO₂ Monoliths

The efficient and low-cost adsorption of arsenic toxins from drinking water is a global concern because of its adverse health effects. The simple extraction and eco-friendly environmental waste management of arsenic(V) species using hierarchy rutile TiO₂ were reported. Mesoporous microscale TiO₂ sphere 3D monoliths were successfully fabricated with uniform mesopores morphology-like blobfish head containing open nanoscale eyes through hydrothermal one-pot synthesis. The blobfish head TiO₂ (BHT) was mainly oriented along the predominant {110} facet and with dense top-surface atomic Ti⁴⁺ and O^2- sites along the crystal edge surface and central crystals. These characteristics lead to efficient adsorption and selective binding to As(V) species in acidic medium. The photoinduced irradiation of the BHT adsorbent promoted significant trapping and high adsorptivity, with a maximum capacity reaching 125 mg/g from drinking water. The BHT adsorbent selectively binds As(V) species among competitive anions, such as chlorides, bicarbonates, and sulfates, as well as cations, such as Ca²⁺, Mg²⁺, Co²⁺, Al³⁺, Ni²⁺, Cd²⁺, Mn²⁺, and Fe³⁺cations, in real samples. Results indicated that the BHT hierarchy can be cycled several times without deteriorating in its significant performances despite the severe treatment under irradiation or chemical treatment agents. The BHT monoliths might be an effective photoadsorbent for final disposals, particularly at low levels of As(V) species in real water sources.