Arsenic pollution of water is one of the severest environmental challenges for human health, and adsorption is the most often used technique in investigations of selective As removal. However, the ...development of low-cost and easily recoverable adsorbent for aqueous arsenic adsorption remains a challenge. In this work, the α-FeOOH-decorated monolith bamboo composites (α-FeOOH/MB) were fabricated via directly decorating α-FeOOH nanoneedles on the waste bamboo framework without pre‑carbonization. As expected, the as-prepared α-FeOOH/MB exhibits considerably increased adsorption capacity for aqueous arsenic over pure α-FeOOH nanoneedles, with increases of 1.88 and 1.52 times for As(V) and As(III), respectively. Meanwhile, the α-FeOOH/MB composites exhibit positive reusability (recovering 89.73 % and 80.17 % adsorption capacity for As(V) and As(III) after 5 cycles) and are easy to separate after water treatment. Furthermore, the α-FeOOH/MB composites exhibit high arsenic adsorption selectivity even in the presence of competing anions. Overall, the as-obtained α-FeOOH/MB composites, reuse of waste bamboo, are a kind of favorable candidate for arsenic decontamination in practical application owing to the high adsorption capacity, low-cost and facile separation features.
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•α-FeOOH-decorated monolith bamboo (α-FeOOH/MB) was synthesized.•Waste bamboo was directly used as the support without any pre-treatment.•Bamboo's inherent 3D monolithic structure facilitates separation and recycling.•The α-FeOOH/MB composites are highly effective for aqueous As(V) and As(III) removal.•Surface complexation was the dominant removal mechanism.
Polymerized high internal phase emulsions as highly porous adsorption materials have received increasing attention and wide applications in separation science in recent years due to their remarkable ...merits such as highly interconnected porosity, high permeability, good thermal and chemical stability, and tailorable chemistry. In this review, we attempt to introduce some strategies to utilize polymerized high internal phase emulsions for separation science, and highlight the recent advances made in the applications of polymerized high internal phase emulsions for diverse separation of small organic molecules, carbon dioxide, metal ions, proteins, and other interesting targets. Potential challenges and future perspectives for polymerized high internal phase emulsion research in the field of separation science are also speculated at the end of this review.
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Three-dimensional flexible nitrogen-doped carbon monoliths (3DNC) were prepared by one-step carbonization method of commercially available melamine foam. The carbonization temperature ...effect on the electrochemical performance of nitrogen-doped carbon monoliths was investigated. With the increase of carbonization temperature, the specific capacitance of binder-free 3DNC electrode intensifies up to 221Fg−1 at a current density of 0.5Ag−1 at 950°C in 2M NaOH and weaken for higher temperature, which can be explained by the balance between nitrogen doping concentration and the specific surface area at different carbonization temperature. Further, the optimized 3DNC exhibits 96% retention after 5000 cycles measurements, indicating its superior long-term stability. Moreover, the assembled symmetric device outputs the maximum energy density of 9.34 Wh kg−1 as well as the maximum power density of 6.9kWkg−1. These results demonstrate the potential application of the designed 3DNC structures for energy storage devices.
The growth of the Hier-Beta zeolite spheres undergoes a reverse crystal-growth route – surface-to-core crystallization. Display omitted
•Hier-Beta is obtained by steam-assisted crystallization of ...carbon–silica monolith.•The growth of the zeolite undergoes the route – surface-to-core crystallization.•Hier-Beta shows high activity in the dehydration of fructose into HMF.
A direct synthetic route for hierarchical Beta zeolite has been developed via steam-assisted crystallization (SAC) of carbon–silica composite monolith. SEM and TEM observations show that Hier-Beta zeolites are rough spheres (diameter: 500–600nm), composed of connected nanoparticles and have single crystallinity. Deep investigation shows that the growth of the zeolite spheres undergo a reverse crystal-growth route – surface-to-core crystallization. Such materials demonstrate the greatly enhanced catalytic activity in the dehydration of fructose into 5-hydroxymethylfurfural (HMF), because of the intra-crystalline mesoporous structure and efficient diffusion of reactant/product molecules.
Photocatalytic conversion of CO2 to fuels has attracted immense attention because it offers a cleaner energy technology and safer environment. In this study, performance of structured montmorillonite ...(MMT) dispersed Fe-doped titanium dioxide (Fe/TiO2) nanocomposite was tested for dynamic photo-induced CO2 reduction by H2 to fuels. Cordierite monolithic support was employed in order to improve the photo-activity and reusability of Fe-MMT/TiO2 nanocomposite in a CO2 utilization process. MMT-clay supported Fe/TiO2 samples were prepared by a controlled and direct sol-gel method and were dip-coated over the monolith micro-channels. The efficiency of Fe-loaded MMT/TiO2 for CO2 reduction by H2 toward CO was investigated using a cell type and a monolith photo-reactor under UV-light. The maximum CO yield over 3 wt % Fe-10 wt % MMT-loaded TiO2 catalyst reached 166 μmole g-catal.−1 h−1 at selectivity 99.70%, considerably higher than the amount of CO produced over the MMT/TiO2 (16 μmole g-catal.−1 h−1) and the pure TiO2 (5 μmole g-catal.−1 h−1) catalysts. The other products observed with adequate amounts were CH4 and C2H6. More importantly, photo-activity and stability of Fe-MMT/TiO2 catalyst for CO evolution was significantly improved using monolith photo-reactor compared to the cell type reactor under the same operating conditions. This enactment was evidently due to higher quantum efficiency of monolith photoreactor, improved adsorption-desorption process in a catalyst coated monolith channels and hindered charges recombination by Fe. The reusability of catalyst loaded over the monolithic support showed greater recycling capability than the catalyst dispersed in a cell reactor. This development confirmed higher photo-activity of Fe-MMT/TiO2 photo-catalyst loaded over monolithic support for CO2 photo-reduction to cleaner fuels.
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Woody biochar monolith with ultra-high carbon content and highly ordered macropores has been prepared via one-pot pyrolysis and carbonization of red cedar wood at 750°C without the need of ...post-treatment. Energy-dispersive spectroscope (EDX) and scanning electron microscope (SEM) studies show that the original biochar has a carbon content of 98wt% with oxygen as the only detectable impurity and highly ordered macroporous texture characterized by alternating regular macroporous regions and narrow porous regions. Moreover, the hierarchically porous biochar monolith has a high BET specific surface area of approximately 400m2g−1. We have studied the monolith material as supercapacitor electrodes under acidic environment using electrochemical and surface characterization techniques. Electrochemical measurements show that the original biochar electrodes have a potential window of about 1.3V and exhibit typical rectangular-shape voltammetric responses and fast charging–discharging behavior with a gravimetric capacitance of about 14Fg−1. Simple activation of biochar in diluted nitric acid at room temperature leads to 7 times increase in the capacitance (115Fg−1). Because the HNO3-activation slightly decreases rather than increases the BET surface area of the biochar, an increase in the coverage of surface oxygen groups is the most likely origin of the substantial capacitance improvement. This is supported by EDX, X-ray photoelectron spectroscopy (XPS), and Raman measurements. Preliminary life-time studies show that biochar supercapacitors using the original and HNO3-activated electrodes are stable over 5000 cycles without performance decays. These facts indicate that the use of woody biochar is promising for its low cost and it can be a good performance electrode with low environmental impacts for supercapacitor applications.
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•Core-double-shell architecture was designed as efficient HER and OER electrocatalysts.•Cobalt phosphide and NiFe-LDH were used as representative HER and OER catalysts.•The ...architecture consist of core–shell porous carbon fiber (CFC@EC) and TMCs.•Lattice distortions were created in the TMCs by CFC@EC, facilitating the exposure of active sites.•Enhanced performance is due to the strong electronic interaction between the hybrids.
Different transition metal compounds (TMCs) nanostructures grown on conductive substrates have been considered as promising self-supportive non-precious electrocatalysts for electrochemical water splitting, but extremely challenging to develop facile and generalized approaches for rational design and enhancing their catalytic properties. Herein, we develop a general strategy to boost the hydrogen and oxygen evolution reactions (HER and OER) performance of TMCs by designing monolith electrocatalyst architectures. The monoliths comprises of TMCs integrated on carbon fiber cloth core–shell (CFC@EC) structure. The CFC@EC allows the creation of numerous lattice distortions and strong electronic interactions between CFC@EC and metal cations of the TMCs. Such lattice distortions exposes more active sites in CFC@EC/TMCs compared to the pristine CFC coated TMCs (CFC/TMC). Cobalt phosphide (CoP) nanowires and NiFe-LDH coated on CFC@EC exhibits the optimized HER and OER activities. Overall water splitting device assembled based on the optimized HER and OER electrodes also achieve low overall potential of 1.53 V at 10 mA cm−2. More importantly, we further experimentally verify that the integration of Ni3N and Ni3S2, CoS2, NiCo-LDH, NiMn-LDH with CFC@EC also reveal similar improved performance, providing a general and valuable strategy into the design of other self-supporting electrocatalysts for water splitting and beyond.
•A new molecularly imprinted monolith-based adsorbent was fabricated.•Molecular simulation technique was used to quickly screen functional monomer.•The prepared MBA exhibited satisfactory specific ...recognition performance.•MBA/MIMD was employed to perform field sample preparation of triazine herbicides.•Approach for the quantification of triazine herbicides in waters was established.
Field selective extraction is crucial for accurate monitoring of triazine herbicides (TAHs) in aqueous samples. For this purpose, using atrazine as template and 3-acrylamido phenylboronic acid as functional monomer which was quickly screened with calculation simulation technology, a new molecularly imprinted monolith-based adsorbent (MBA) was fabricated and utilized as the extraction phase of laboratory-made multichannel in-tip microextraction device (MIMD). A series of techniques were adopted to characterize the physical and chemical properties of the synthesized MBA. Under the optimized preparation conditions, the recognition factor and capture capacity of MBA towards atrazine were as high as 2.9 and 23.4 mg/g, respectively, and the enrichment factors towards TAHs located in the range of 276–359. The study about adsorption isotherm evidenced the adsorption of MBA towards atrazine was fit for Freundlich adsorption model. Under the beneficial extraction parameters, the introduced MBA/MIMD was utilized to on-site extract TAHs in a variety of aqueous samples prior to HPLC determination. High sensitivity (limit of detection: 0.25–0.64 ng/L), good precision (relative standard deviation: 1.4–9.5%) and satisfying recovery (81.0–113%) were achieved. Accuracy and reliability of the introduced method were inspected through confirmation experiments. Owing to the good results and outstanding merits, the established MBA/MIMD technique is appropriate for field sample preparation of TAHs and the developed method can be utilized to monitor TAHs residuals in various aqueous samples.
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•S-doped carbon monoliths (rock-like) was developed via nanocasting and chemical activation method.•Synthesized monoliths showed remarkably high dynamic CO2 adsorption capacities at ...30 °C.•The monolithic adsorbents exhibited excellent regeneration performance after five cycles.•CO2 adsorption process followed Temkin isotherm model.
Advanced and effective adsorbents synthesized via cost-effective methods are needed for CO2 capture applications. Heteroatom doping is regarded as one of the major factor of the porous carbons for efficient CO2 adsorption. In the present study, oxygen and sulfur enriched carbon monoliths were prepared using nanocasting technique followed by chemical activation method. Low-cost phenol-formaldehyde (PF) resin and sodium thiosulphate were chosen as the carbon and sulfur source, respectively. The surface area of the monolithic carbons varied from 390 to 510 m2 g−1 and sulfur content was 2.89 wt% in the S-doped monolith. The effect of different adsorptive operating conditions i.e. adsorption temperatures and CO2 concentrations on the CO2 capture capacities were evaluated. The nanocasted monoliths exhibited excellent dynamic adsorption capacities (1.35–2.10 mmol g−1), which are much greater than in the case of direct carbonized PF sample (0.97 mmol g−1). This is ascribed to the fact that the surface area gets enhanced by implementing nanocasting method whereas the incorporation of oxygen and sulfur functionalities increases the basic character of the monoliths. The as-prepared monolith shows the stable and excellent regenerability over subsequent adsorption and desorption cycles. Moreover, the Temkin isotherm model best fitting with adsorption data indicates the heterogeneous surface of the monoliths. Combined with the effective synthesis of the monoliths, high CO2 uptake, and easy regenerability could make it a most suitable material for CO2 adsorption in the practical applications.
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Environmental concern associated with excess fluoride has intrigued the unceasing exploration of new multifunctional hybrid materials to mitigate any undesirable consequence to human ...health. Herein, a novel hybrid monolith has been successfully fabricated via a facile in-situ growth strategy for highly efficient defluoridation from contaminated waters, in which homogeneously dispersed UiO-66 particles are perfectly anchored on three dimensional (3D) porous carbon foam (CF). Benefiting from fully exposed active sites, excellent pore accessibility and efficient mass transport, the integrated UiO-66/CF hybrid monolith exhibits fast adsorption kinetics, and outstanding uptake capacity toward fluoride as high as 295 mg g−1, which greatly outperforms the previously reported adsorbents. Furthermore, the fluoride removal efficiency of the spent monolith can reach up to 70% after four cycles, accompanied by facile separation nature and outstanding water stability. More significantly, the resulting UiO-66/CF packed column (0.36 g) can continuously treat 400 mL of F− solution with 6.2 mg L−1 before the breakthrough point occurs, highlight its potential feasibility for fluoride removal in the practical applicability.
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