Large-scale uranium extraction from seawater (UES) is widely considered as reconciliation to increasing global energy demand and climate change crises. However, an ideal uranium sorbent combining features of high capacity,...
Water pollution has attracted worldwide significant attention ever since the finding of its harmful effects on the whole ecosystem, including human health. Although several materials are known for selective removal of specific contaminants, designing a single material that can adsorb a variety of water contaminants is still a very challenging task due to a lack of proper design strategies. Herein, we have rationally designed a new class of anion exchangeable hybrid material where the nanosized cationic metal–organic polyhedra (MOP) are embedded inside a porous covalent organic framework (COF) with specific binding sites for toxic oxoanions. The resulting hybrid material exhibits very fast and selective sequestration of high as well as trace amount of a wide range of toxic oxoanions (HAsO 4 2– , SeO 4 2– , CrO 4 2– , ReO 4 – , and MnO 4 – ) from the mixture of excessive (∼1000-fold) other interfering anions to well below the permissible drinking water limit. Moreover, the hybrid cationic nanotrap material can reduce the As(V) level from a highly contaminated groundwater sample to below the WHO permitted level.
Metal-based oxoanions are potentially toxic pollutants that can cause serious water pollution. Therefore, the segregation of such species has recently received significant research attention. Even though several adsorbents have been employed for effective management of chemicals, their limited microporous nature along with non-monolithic applicability has thwarted their large-scale real-time application. Herein, we developed a unique anion exchangeable hybrid composite aerogel material (IPcomp-6), integrating a stable cationic metal-organic polyhedron with a hierarchically porous metal-organic gel. The composite scavenger demonstrated a highly selective and very fast segregation efficiency for various hazardous oxoanions such as, HAsO 4 2À , SeO 4 2À , ReO 4 À , CrO 4 2À , MnO 4 À , in water, in the presence of 100-fold excess of other coexisting anions. The material was able to selectively eliminate trace HAsO 4 2À even at low concentration to well below the As V limit in drinking water defined by WHO.
In recent years, detoxification of contaminated water by different types of materials has received a great deal of attention. However, lack of methodical in-depth understanding of the role of various physical properties of such materials toward improved sorption performance limits their applicable efficiencies. In perspective, decontamination of oxoanion-polluted water by porous materials with different morphologies are unexplored due to a shortfall of proper synthetic strategies. Herein, systematic optimization of sequestration performance toward efficient decontamination of toxic oxoanion-polluted water has been demonstrated by varying the morphologies of an imidazolium-based cationic polymeric network [ionic porous organic polymers (iPOP-5)]. Detailed morphological evolution showed that the chemically stable ionic polymer exhibited several morphologies such as spherical, nanotube, and flakes. Among them, the flakelike material [iPOP-5(F)] showed ultrafast capture efficiency (up to ∼99 and >85% removal within less than 1 min) with high saturation capacities (301 and 610 mg g–1) toward chromate [Cr(VI)] and perrhenate [Re(VII)] oxoanions, respectively, in water. On the other hand, the spherical-shaped polymer [iPOP-5(S)] exhibited relatively slow removal kinetics (>5 min for complete removal) toward both Cr(VI) and Re(VII) oxoanions. Notably, iPOP-5(F) eliminated Cr(VI) and Re(VII) selectively even in the presence of excessive (∼100-fold) competing anions from both high- and low-concentration contaminated water. Further, the compound demonstrated efficient separation of those oxoanions in a wide pH range as well as in various water systems (such as potable, lake, river, sea, and tannery water) with superior regeneration ability. Moreover, as a proof of concept, a column exchange-based water treatment experiment by iPOP-5(F) has been performed to reduce the concentration of Cr(VI) and Re(VII) below the WHO permitted level. Mechanistic investigation suggested that the rare in situ exfoliation of flakes into thin nanosheets helps to achieve ultrafast capture efficiency. In addition, detailed theoretical binding energy calculations were executed in order to understand such rapid, selective binding of chromate and perrhenate oxoanions with iPOP-5(F) over other nonmetal-based anions.
generations. This has necessitated the enhanced use of renewable forms of energy. While solar energy and wind energy are perhaps the most explored forms of renewables, other forms such as mechanical energy have received relatively less attention. In fact, the energy from diverse mechanical motions such as body motion, wind, and water tidal energy has been mostly squandered and ignored in the past. Fortunately, the scientific community has begun to take notice of the availability of such other energy sources available to us as a partial solution to the growing energy-related problems. [1,2] Indeed, in the recent decade, mechanical energy conversion technologies have witnessed substantial progress, especially in the area of distributed micro/nano-power sources, portable high-voltage sources, wearable electronics, and high-precision sensors. At the heart of this progress are the devices known as triboelectric nanogenerators (TENGs) which basically exploit the concept of charge separation accomplished by relative motion between two dissimilar materials in proximity, the well-known phenomenon of friction being an expression of the process. [3] The dissimilarity of materials emanates from Triboelectric nanogenerators (TENGs) are receiving significant attention lately as efficient mechanical energy harvesting devices. They are finding multiple uses in numerous low-power applications. Current TENG designs, although innovative, fall short on practical demands like performance tunability, modulatory, and stability. This invites further research in the use of new materials for TENGs. Metal-organic frameworks (MOFs) offer a unique feature of molecular tunability to optimize energy conversion which has been exploited in this study. Prototypal hybridization strategy is deployed on underexplored isoreticular subfamily UiO-66(Zr) MOFs through UiO-66-X/PVDF (X = H or Br) composites for TENG output tuning and amplification. UiO-66-X/PVDF exhibits good aquatic and thermal stability accompanying substantial boost in TENG power. Functionalized H 2 BDC linker improved surface roughness and potential. UiO-66-Br encased in PVDF matrix boosted charge and TENG performance by enhancing electrification. Computational details support observations. Device captures waste energy in a vertical contact-separation mode and functions consistently amidst diverse environmental settings. Functionalized TENG-2 delivers a V p-p of 110.41 V, which is 2.92 times and 14.12 times higher than unfunctionalized TENG-1 and PVDF film, respectively. Findings reveal maiden example of ligand-mediated functional group-driven performance tuning of TENG and mechanistic insight using isoreticular MOFs/PVDF composites.
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