Bushy sphere dendrites with husk-shaped branches axially spreading out from the core for photo-catalytic oxidation/remediation of toxins.

This work describes densely interlinked bushy "tree-like chains" characterized by neatly branched sphere dendrites (bushy sphere dendrites, BSD) with long fan-like, husk-shaped branching paths that extend longitudinally from the core axis of the {110}-exposed plane. We confirmed that the hierarchical dendrite surfaces created bowls of swirled caves along the tree-tube in the mat-like branches. These surfaces had high-index catalytic site facets associated with the formation of ridges/defects on the dominant {110}-top-cover surface. These swirled caves along the branches were completely filled with 50-100 nm poly-CN nano-sphere-fossils with orb-like appearance. Such structural features are key issues of the inherent surface reactivity of a powerful catalyst/trapper, enabling photocatalytic oxidation and trapping of extremely toxic arsenite (AsO33-) species and photo-induced recovery of arsenate (AsO43-) products from catalyst surfaces. The light-induced release of produced AsO43- from BSD indicates (i) highly controlled waste collection/management (i.e., recovery), (ii) low cost and ecofriendly photo-adsorbent, (iii) selective trapping of real sample water to produce water-free arsenite species; (iv) multiple reuse cycles of catalysts (i.e., reduced waste volume). Matrixed dendrites, covered with 3D microscopic sphere cores that capture solar-light, trap toxins, and are triggered by light, were designed. These dendrites can withstand indoor and outdoor recovery of toxins from water sources.

Effective, Low-Cost Recovery of Toxic Arsenate Anions from Water by Using Hollow-Sphere Geode Traps.

Because of the devastating impact of arsenic on terrestrial and aquatic organisms, the recovery, removal, disposal, and management of arsenic-contaminated water is a considerable challenge and has become an urgent necessity in the field of water treatment. This study reports the controlled fabrication of a low-cost adsorbent based on microscopic C-,N-doped NiO hollow spheres with geode shells composed of poly-CN nanospherical nodules (100 nm) that were intrinsically stacked and wrapped around the hollow spheres to form a shell with a thickness of 500-700 nm. This C-,N-doped NiO hollow-sphere adsorbent (termed CNN) with multiple diffusion routes through open pores and caves with connected open macro/meso windows over the entire surface and well-dispersed hollow-sphere particles that create vesicle traps for the capture, extraction, and separation of arsenate (AsO43- ) species from aqueous solution. The CNN structures are considered to be a potentially attractive adsorbent for AsO43- species due to 1) superior removal and trapping capacity from water samples and 2) selective trapping of AsO43- from real water samples that mainly contained chloride and nitrate anions and Fe2+ , and Mn2+ , Ca2+ , and Mg2+ cations. The structural stability of the hierarchal geodes was evident after 20 cycles without any significant decrease in the recovery efficiency of AsO43- species. To achieve low-cost adsorbents and toxic-waste management, this superior CNN AsO43- dead-end trapping and recovery system evidently enabled the continuous control of AsO43- disposal in water-scarce environments, presents a low-cost and eco-friendly adsorbent for AsO43- species, and selectively produced water-free arsenate species. These CNN geode traps show potential as excellent adsorbent candidates in environment remediation tools and human healthcare.

Mesotubular-Structured Hybrid Membrane Nanocontainer for Periodical Monitoring, Separation, and Recovery of Cobalt Ions from Water.

Exposure to toxins can cause deleterious effects even at very low concentrations. We have developed an optical sensor, filter, and extractor (i.e., containerlike) in a nanoscale membrane (NSM) for the ultratrace sensing, separation, and recovery of Co(2+) ions from water. The design of the NSM is successfully controlled by dense decoration of a hydrophobic oil-hydrophilic receptor onto mesoscale tubular-structured silica nanochannels made of a hybrid anodic alumina membrane. The particular structure of the nanocontainer is ideal to control the multiple functions of the membrane, such as the optical detection/recognition, rejection/permeation, and recovery of Co(2+) species in a single step. A typical sensor, filter, and extractor assessment experiment was performed by using a benchtop contact time technique and a flow-through cell detector to allow for precise control of the optical detection and exclusive rejection of target ions and the permeation of nontarget metal ions in water. This nanocontainer membrane has great potential to meet the increasing needs of purification and separation of Co(2+) ions.