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Developing multifunctional materials with oil/water separation, dye adsorption, and antibacterial activities presents an enticing prospect for wastewater treatment. In this paper, a three-dimensional (3D) porous cellulose (CE)/quaternized cellulose (QCE) composite aerogel with super-wettability through co-deposition of polydopamine (PDA) and polyethylenimine (PEI) is reported. The PDA/PEI coating endows the aerogel with superhydrophilicity (WCA = 0°), and the QCE act as an anionic dye sorbent at the same time, endowing the material with antimicrobial activity against Escherichia coli (E. coli). Oil/water mixtures can be separated on an as-prepared aerogel with high efficiency (>99%), even when the filtration was repeated 10 times, and the as-prepared aerogel can also separate oil-in-water emulsions. Moreover, the as-prepared aerogel exhibited excellent adsorption performance for alizarin red, with a calculated maximum adsorption capacity of 454.545 mg g−1. Besides, our modification also endowed the aerogel with antibacterial and anti-oil-fouling activities. The inhibition zone test verified the efficient elimination of E. coli. This work may open a new avenue for designing versatile aerogel with multiple functions for waste water remediation. [ABSTRACT FROM AUTHOR]

Carbon aerogels, usually prepared from organic aerogel precursors, have many merits such as being light weight, high porosity, large surface area, excellent conductivity, and high temperature resistance for broad applications in the fields of adsorption, catalysis, and energy storage. Particularly, the application of carbon aerogels in advanced energy storage devices has gained increasing attention in recent years. This paper discusses the preparation and application of carbon aerogels derived from organic precursors. The development of resin- and biomass-derived carbon aerogels for application in supercapacitors and rechargeable batteries (e.g., Li-ion batteries – LIBs) is highlighted. Furthermore, the development and challenges of the carbon aerogel industry are discussed. This work offers a strategic guide to build a close connection between carbon aerogels and the energy storage economy. In general, the electrochemical performances mostly rely on the surface structures and chemical characteristics of carbon aerogels. Carbon aerogels possessing a 3D hierarchical porous network structure with appropriate microporosity and mesoporosity, heteroatom (e.g., N, S) doping, and active metal nanoparticle (e.g., MnO2, Co3O4) loading are key indexes to determine the capacitance, rate capability, and cycling stability of the assembled supercapacitors. Resin-derived carbon aerogels have the advantages of large specific surface area and highly tunable pores for application in supercapacitors, but the poor mechanical properties hinder their application in flexible supercapacitors. In addition, carbon aerogels for application in rechargeable batteries are mostly used as the supports for electroactive substances in LIBs and the separators of Li–S and Na–S batteries. Carbon aerogels derived from biomass precursors, in comparison with conventional resin precursors, are promising alternatives owing to the benefits of low cost (abundant in nature), sustainability, eco-friendliness, large specific surface areas, tunable pore structures, and strong mechanical properties. The challenges of promoting biomass-derived carbon aerogels for practical use include simplifying the procedure and further reducing the time and cost required for the preparation of carbon aerogels from diverse biomass precursors. [ABSTRACT FROM AUTHOR]

Ti3C2Tx has been extensively used as a promising sensing material for the construction of electrochemical sensors because of its excellent conductivity, surface area and mechanical properties, but the two-dimensional structure and poor catalytic activity of Ti3C2Tx limit the improvement of its analytical behavior. This paper reports a facile method for the synthesis of a Ti3C2Tx@gold nanoparticle-arginine- and serine-functionalized graphene quantum dot aerogel (Ti3C2Tx@Au–AS-GQD). AS-GQD was prepared by heating a mixture of citric acid, arginine and serine. The formed AS-GQD was used to reduce chloroauric acid to produce gold nanoparticles. The gold nanoparticles protonated with hydrochloric acid were dropped into a Ti3C2Tx aqueous solution to form Ti3C2Tx@Au–AS-GQD. The Ti3C2Tx@Au–AS-GQD shows one three-dimensional structure. Small gold nanoparticles were uniformly dispersed on the Ti3C2Tx sheets. The introduction of AS-GQD resulted in the formation of Schottky heterojunction and enhanced the catalytic activity. The electrochemical sensor fabricated with Ti3C2Tx@Au–AS-GQD exhibited high sensitivity, selectivity and repeatability in the electrochemical detection of chloramphenicol. The differential pulse voltammetric current at −0.6 V linearly increased with the increase in chloramphenicol within 0.003–100 μM, exhibiting a detection limit of 0.0012 μM (S/N = 3). The sensitivity of our sensor toward chloramphenicol was better than those of other electrochemical sensors. This study also paves an avenue for the construction of Ti3C2Tx composites with excellent catalytic activity in sensing, catalysis and energy storage and conversion. [ABSTRACT FROM AUTHOR]

The assembly of 2D Ti3C2Tx nanosheets into 3D structures with orderable structure has great importance for their use as catalyst carriers. However, Ti3C2Tx nanosheets are prone to accumulate in aqueous solutions owing to the strong van der Waals forces between Ti3C2Tx nanosheet layers, degrading their chemical properties. Carbon aerogel (Ti3C2Tx/G/Co) with a 3D porous structure and cobalt as the active site was prepared by a simple co-assembly–freeze–drying–high-temperature carbonization method for application in catalysis of ammonium perchlorate. [ABSTRACT FROM AUTHOR]

In this work, a high density of dispersed Co9S8 nanoparticles (NPs) loaded in carbon aerogels as bi-catalysts (Co9S87.5NP/CA catalysts) were successfully prepared by virtue of the seeded-growth method that is widely used for the synthesis of noble metal NPs. It is found that the optimal molar ratio of Co2+-to-Fe3+ ions for the formation of a high density of dispersed Co9S8 NPs with average sizes of 90 nm is determined to be 7.5 (represented by the superscript number) at the fixed concentration of tannic acid (TA) ([TA] : [Fe3+] = 1 : 1). Moreover, the concentration of Fe3+ precursors is the key that can guarantee the formation of dispersed Co9S8 NPs by the overgrowth of in situ Fe SA-NCs as seeds by the spatial confinement effect during the pyrolysis. Thanks to the multiple valence states of elemental Co in the Co9S8 NPs and their good dispersity in the as-prepared Co9S87.5NP/CA catalysts, the half-wave potential (E1/2) and the overpotential at 10 mA cm−2 (η10) towards the alkaline oxygen reduction reaction (ORR) and the acidic hydrogen evolution reaction (HER) can be improved up to 0.891 V and 177 mV, respectively. [ABSTRACT FROM AUTHOR]

Designing innovative microstructures and implementing efficient multicomponent strategies are still challenging to achieve high-performance and chemo-mechanically stable electrode materials. Herein, a hierarchical three-dimensional (3D) graphene oxide (GO) assisted Ti3C2Tx MXene aerogel foam (MXene-GAF) impregnated with battery-type bimetallic nickel vanadium selenide (NiVSe) has been prepared through a hydrothermal method followed by freeze-drying (denoted as NiVSe–MXene-GAF). 3D-oriented cellular pore networks benefit the energy storage process through the effective lodging of NiVSe particles, improving the access of the electrolyte to the active sites, and alleviating volume changes during redox reactions. The 3D MXene-GAF conductive matrix and heterostructured interface of MXene–rGO and NiVSe facilitated the rapid transport of electrical charges and ions during the charge–discharge process. As a result of the synergism of these effects, NiVSe–MXene-GAF exhibited remarkable electrochemical performance with a specific capacity of 305.8 mA h g−1 at 1 A g−1 and 99.2% initial coulombic efficiency. The NiVSe–MXene-GAF electrode delivered a specific capacity of 235.1 mA h g−1 even at a high current density of 12 A g−1 with a 76.8% rate performance. The impedance measurements indicated a low bulk solution resistance (Rs = 0.71 Ω) for NiVSe–MXene-GAF. Furthermore, the structural robustness of NiVSe–MXene-GAF guaranteed long-term stability with a 91.7% capacity retention for successive 7000 cycles. Thus, developing NiVSe–MXene-GAF provides a progressive strategy for fabricating high-performance 3D heterostructured electrode materials for energy storage applications. [ABSTRACT FROM AUTHOR]

As a dual-functional catalyst for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER), Ru clusters have great potential, but there are certain difficulties regarding their stability on the substrate and the tunability of their electronic environment. Here, the S doped graphited biochar aerogel electrocatalyst was designed and synthesized using terrestrial lignin and algal polysaccharide as a carbon substrate. The Ru clusters were anchored on the S-doped carbon aerogel (P-Ru/SC) by carefully designing the Ru-S bond via a novel plasma assisted high temperature carbonization treatment. The optimized P-Ru/SC-2 catalyst exhibits excellent electrocatalytic performance for the HER and OER, achieving ultra-small overpotentials of 119.6 mV and 193.4 mV at 10 mA cm-2. The dual-electrode requires only 1.47 V to reach 10 mA cm-2. It is worth noting that a large number of S sites on graphited carbon can strongly interact with the Ru clusters, significantly improving the catalytic activity and stability for the HER and OER. [ABSTRACT FROM AUTHOR]

N-doped carbon aerogel capsulated Co3O4 (Co3O4@NCA) is prepared via a hydrothermal method using an N-doped carbon aerogel (NCA) as a conductive carbon matrix and coating layer. Kinetic parameters are investigated using CV and GITT methods, and the improved performance could be ascribed to rapid lithium-ion diffusion and enhanced pseudocapacitance contribution induced by the introduction of carbon aerogel conductive matrices and the construction of porous nanomicro-hierarchical architectures, which endow the material with a large surface area, good conductivity, abundant pore channels, and plentiful defects and active sites, thus greatly increasing the lithium storage capacity. Used as an anode for lithium-ion batteries, Co3O4@NCA-1 displays a reversible capacity of 600.2 mA h g-1 during the 200th cycle under 100 mA g-1, 5.13 times larger than the specific charge capacity of 116.8 mA h g-1 for Co3O4 samples. Even if the current density is increased to 1 A g-1, it has 4.48 times the charge capacity of pure Co3O4. The Co3O4 modification strategy using NCA as a matrix to fabricate nanomicro-hierarchical architectures demonstrates potential applications in the energy storage field. [ABSTRACT FROM AUTHOR]

Cellulose nanofiber (CNF) is an environmentally friendly material with a high specific surface area, which is an ideal candidate for cathode catalysts in zinc–air batteries (ZABs). However, untreated CNF-based carbon materials suffer from low intrinsic activity and fewer micro-mesopores. Herein, we developed an N-doped porous carbon aerogel from CNF and graphite phase carbon nitride (g-C3N4) via hydrothermal pretreatment and the carbonization process. The CNF can serve as the skeleton of the aerogel that leads to an interconnected porous structure, while g-C3N4 guarantees the in situ N doping and the formation of more nanopores. Therefore, the as-prepared carbon aerogel exhibits excellent oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) performances owing to the successful N doping with sufficient graphite-N and pyridine-N active sites (69.1%) and high specific surface areas (785.4 m2 g−1). The assembled ZABs with a carbon aerogel deliver a specific capacity of 790 mA h g−1 and an energy density of 945.6 W h kg−1 with a long-term stability over 100 h. This work opens a new avenue for the effective conversion of abundant biomass into bifunctional air cathodes for energy-related applications. [ABSTRACT FROM AUTHOR]

A three-dimensional (3D) Pd–In2O3/rGO aerogel was fabricated via a one-step hydrothermal treatment and freeze-drying. The morphology and structure of the 3D Pd–In2O3/rGO aerogel were examined. The aerogel material had a porous network structure, which was particularly advantageous for gas adsorption. The Pd–In2O3 nanoparticles were uniformly grown on the thin layer of rGO. The specific surface area of the aerogel and its rich pore structure inhibited aggregation and accumulation of the nanoparticles. Moreover, this structure facilitated the formation of a P–N heterogeneous structure, which ultimately enabled successful detection of hydrogen (H2) at room temperature. The sensitivity for 10 000 ppm H2 at room temperature was 27.66, and detection was stable and reproducible. Most notably, the response and recovery times for H2 were as short as 11 and 13 seconds, respectively. The addition of a hydrogen-sensitive functional material to a reduced graphene oxide aerogel shows great promise for room temperature gas sensing. [ABSTRACT FROM AUTHOR]

In this paper, a Ag–Co3O4/graphene aerogel (GA) composite was prepared by dispersing Ag-modified low crystalline Co3O4 nanowires onto a GA carrier. The capacitive performance of the Ag–Co3O4/GA was studied and the results were compared with those of Co3O4/GA. Ag-functionalized Co3O4/graphene with precursor n(Ag)/n(Co) = 0.51 exhibited the highest specific capacitance (Cs) value of 1180 F g−1 at a current density of 1 A g−1, and the capacity retention was 86% after 1000 cycles at 5 A g−1. Furthermore, the electrochemical impedance spectroscopic results revealed a certain effect of electrolyte ions on the supercapacitive behavior. Ag-functionalized Co3O4/GA is believed to be one of the potential materials for supercapacitors with high performance. [ABSTRACT FROM AUTHOR]

Nowadays, physical absorption has become a feasible method to tackle the increasingly severe marine pollution. However, traditional aerogels suffer from low oil absorption capacity and poor compressibility, and high performance aerogels typically have the drawbacks of complex process flow and expensive raw materials. In this paper, inexpensive industrial raw material melamine was introduced into a graphene aerogel framework, and the aerogel presented ultralow density (3.54 mg cm−3), super-hydrophobicity (water contact angle is 158.2°), and excellent absorption capacity (440 g g−1). Melamine doping gives the graphene aerogel a honeycomb-like porous structure and excellent hydrophobicity, enhancing the flow and adsorption of organic solvents in the aerogel. It has a high application value for solving water pollution problems caused by oil spill accidents and chemical spills. [ABSTRACT FROM AUTHOR]

Selective reduction is one of the most essential and frequently used transformations in organic synthesis. In this work, we developed a novel copper-based biomass-carbon aerogel catalyst (Cu(OTf)2@CAC) as a highly efficient and selective catalyst for maleimide reduction with hydrosilane as a hydrogen source for the first time. A strategy integrating chitin dissolution, nanofibrous regeneration, aerogel construction, and customizable carbonization was designed for the reduction of copper trifluoromethane sulfonate (Cu(OTf)2) to Cu(0) and Cu(I) on the CAC. The Cu(OTf)2@CAC exhibited excellent catalytic activity, chemo-selectivity, and recyclability for selective maleimide reduction to succinimides under mild conditions. Moreover, the Cu(OTf)2@CAC can be reused six times without noticeably losing activity. This work provides a representative and referential approach to achieve efficient catalytic conversion based on the reprocessing and customizable treatment of waste biomass resources. [ABSTRACT FROM AUTHOR]

The development of a highly effective microwave absorber with low filler loading remains a huge challenge. Herein, ultralight three-dimensional graphene/silver nanowire aerogel composites were prepared by a polyol and lyophilization method, and were employed as an effective filler in the fabrication of a high-performance electromagnetic wave absorber. The impedance matching was distinctly optimized by adjusting the ratio between the one-dimensional silver nanowires and two-dimensional graphene nanosheets of the composites, as well as the filler loading. A maximum reflection loss value of −50.25 dB and an effective absorption bandwidth of 5.95 GHz were obtained for the graphene/silver nanowire aerogel composite, with an ultra-low 5 wt% filler loading. The outstanding performance was mainly attributed to interfacial polarization caused by rich heterogeneous contact between the silver nanowires and graphene nanosheets, and internal multi-scattering absorption caused by abundant aerogel pores. This work offers a reliable method for fabrication of an ultra-lightweight aerogel-based microwave absorber with ultra-low filler loading for effective electromagnetic attenuation. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) have attracted extensive attention as promising materials for the elimination of various organic pollutants due to their high surface area, inherent porosity and tailorable functionality. However, powdery COFs are difficult to separate and reuse, which greatly limits their practical applications. Herein, a β-cyclodextrin functionalized imine COF (β-CD-COF) aerogel with good crystallinity and chemical stability was synthesized by the Schiff base reaction using a one-pot method for efficient removal of anionic and cationic dyes from water. The prepared β-CD-COF aerogel has a macroscopic three-dimensional bulk and hierarchical porous structure, which is conducive to adsorption and recovery, and it not only showed high adsorption capacity and fast binding kinetics for single anionic and cationic dyes (3403.91 mg g−1 for methyl orange (MO) and 2199.37 mg g−1 for methylene blue (MB)), but also exhibited outstanding simultaneous adsorption capacity in different binary and ternary pollutant systems. Additionally, the β-CD-COF aerogel showed good reusability for the co-adsorption of MO and MB. These results demonstrate the great potential of β-CD-COF aerogels for the simultaneous removal of anionic and cationic dyes in environmental applications. [ABSTRACT FROM AUTHOR]

Procyanidins (PC) are formed by the polymerisation of flavan-3-ol monomers, which have excellent bioactivity and present great health benefits. However, the application range of the PC is greatly limited due to their poor stability. Therefore, in this study, starch aerogels were used as carriers to encapsulate PC. After screening, wheat starch aerogel (WSA) was finally chosen to encapsulate PC. Afterward, characterization (SEM, XRD, FT-IR, TGA and BET), stability testing, investigations on antioxidant activity, and in vitro tests simulating digestion were carried out. The results of relevant characterization showed that the micro surface structure of the procyanidin wheat starch aerogel (PC-WSA) presented a network structure, and PC were encapsulated in WSA. In addition, PC-WSA allows PC to be released in the final stage of simulated digestion. Meanwhile, the results of antioxidant experiments indicate that PC-WSA exhibits antioxidant activity after encapsulating PC. Moreover, the retention of PC in PC-WSA was still 53.63 ± 3.23% when stored at 70 °C for 20 days. After 6 days of light exposure, the retention of PC in PC-WSA under different light sources was all above 85%, which was higher than that of PC. In conclusion, the wheat starch aerogel could improve the stability of PC and has great potential for application. [ABSTRACT FROM AUTHOR]

In this paper, sweet potatoes (Ipomoea batatas) are used as low-cost precursors to synthesize carbon aerogels with a hierarchical meso–macroporous and branching nanostructure (HMM-BNCA). An HMM-BNCA-modified glassy carbon electrode (GCE) (HMM-BNCA/GCE) exhibits high electrocatalytic activity for some electroactive biomolecules. For ascorbic acid (AA), the HMM-BNCA/GCE exhibits low oxidation peak potential and detection limit (−0.005 V and 0.45 μM, S/N = 3), high sensitivities (195.43 and 121.00 μA mM−1 cm−2) and wide linear ranges (10–1250 μM and 1250–4750 μM), which are superior to those obtained at the GCE and carbon nanotube (CNT)-modified GCE (CNT/GCE). The HMM-BNCA/GCE exhibits significant resistance to fouling and the interfering substances for the detection of AA. The successful and accurate detection of AA in real samples (such as vitamin C injections and vitamin C soft drinks) in this work demonstrates the feasibility and tremendous potential of HMM-BNCA/GCE for the analysis of AA in complex systems. [ABSTRACT FROM AUTHOR]

The quest for advanced water purification technologies has been vigorous over recent decades, motivated by the promise of ever more efficient, greener, and affordable tools. Halloysite nanotubes (HNTs) are naturally-occurring materials that have shown potential as dye sorbents. Unfortunately, these nanoclays suffer from low permeation during water treatment, which limits their widespread application. Here, we use cellulose nanocrystals (CNCs) as structural scaffolds to support HNTs and fabricate permeable aerogel sorbent materials with mechanical stability. Aerogels containing 40 wt% HNTs showed a maximum dye adsorption capacity of 60 mg g−1 towards methylene blue, with only 15% decay in efficiency after 5 cycles. The good mechanical properties of these materials allowed for their incorporation into free-flowing purification columns that displayed excellent dye removal ability. Overall, this work provides a new strategy to fabricate green, renewable, and low-cost sorbent materials for the removal of dyes and shows potential for the sorption of other ionic pollutants. [ABSTRACT FROM AUTHOR]

Diabetes and impaired glucose regulation (IGR) threaten the lives and health of numerous patients. Interstitial fluid (ISF) glucose, displaying an excellent correlation with blood glucose, is highly desired to address the limitations of invasive and minimally invasive glucose detection. Herein, we present a screen-printed iontophoretic biosensing system to extract ISF noninvasively and perform in situ instant glucose detection. A three-dimensional graphene aerogel combined with Prussian blue (GA@PB) was introduced as an electron mediator, providing suitable support for glucose oxidase (GOx) immobilization, highly boosting the detection sensitivity. Additionally, a self-made diffuse cell and an ex vivo model were developed to demonstrate the efficacy of ISF extraction based on reverse iontophoresis technology. Highly sensitive and accurate detection of ISF glucose could be achieved with an LOD of 0.26 mM over a 0–15 mM range. Finally, tests on healthy volunteers were conducted to further validate the feasibility of this as-proposed system. Combined with its well flexible and biocompatible features, it holds considerable prospects in the development of wireless wearable biosensors for continuous blood glucose monitoring. [ABSTRACT FROM AUTHOR]

Histamine is an organic nitrogenous compound released from mast cells, often as part of an instant immune response. Life-threatening anaphylaxis can occur with significant histamine intolerance, which is also referred to as histaminosis caused by overproduction of histamine in the body. Herein, we demonstrate the synthesis of FeS2-incorporated rGO aerogel (FeS2-AG) by lyophilization, as an active SERS substrate for the detection of histamine in blood serum. The morphological characterization revealed the nanoflower structure of FeS2 and uniform porosity of the aerogel, in which the nanoflower structure of FeS2 was homogenously distributed on the surface of the porous aerogel. The cubic structure of FeS2 nanoflowers was revealed by X-ray diffraction and Fourier transform infrared spectroscopy demonstrated the characteristic peak at ∼1176 cm−1 which is related to pyrite surface chemistry of FeS2 nanoparticles. The as-fabricated sensor exhibited an enhancement factor of 1.61 × 107 with a limit of detection of 0.08 ng mL−1. The substrate exhibited a good selectivity and linear range of detection towards histamine in the presence of 2-fold concentration of ascorbic acid, glucose, urea, and uric acid. This excellent performance of the sensor can be ascribed to the chemical enhancement occurring via the interaction of oxy functional groups of aerogel and multiple coordination sites (ferrous ions (Fe2+)) of FeS2 with histamine molecules causing reconstruction of the band gap. This newly formed energy band further leads to the occurrence of the Raman resonance effect, providing an enhancement in the SERS signal over that of the Raman signal obtained from bulk histamine. The sensor showed good recovery percentage of 97.25% from real samples, highlighting the efficiency of the as-fabricated sensor towards histamine detection. [ABSTRACT FROM AUTHOR]

In this work, the preparation of magnetic graphene noble metal aerogels (GA–Fe3O4–Au–ethanol) was realized by self-assembly induced by radiation reduction. The prepared material GA–Fe3O4–Au–ethanol can be easily attracted by a magnet. Meanwhile, GA–Fe3O4–Au–ethanol successfully realized the degradation of 4-nitrophenol (4-NP), which was considered an environmentally harmful pollutant. It is worth mentioning that the prepared materials showed a better catalytic performance than general noble metal catalysts, and it was found that the content of noble metals in the fabricated composite significantly influenced the catalytic reaction rate. The successful preparation of this material provides a feasible scheme for treating pollutant 4-NP. [ABSTRACT FROM AUTHOR]

At present, it is challenging to improve the activity and humidity resistance of ozone catalysts. Herein, an integrated MnOx–Al2O3 aerogel was prepared by a sol–gel method in this study, and its application in catalytic ozonation of toluene was explored preliminarily. Compared with the MnOx–SiO2 aerogel and impregnation catalysts (MnOx–silicalite-1 and MnOx–γ-Al2O3), the MnOx–Al2O3 aerogel exhibited superior performance in toluene removal and enhanced ozone utilization efficiency under optimal conditions (room temperature, O3 : C7H8 = 14 : 1, GHSV = 45 000 h−1 and 120 ppm C7H8). After reacting for 360 min, the 5 wt% MnOx–Al2O3 aerogel still showed stable catalytic ability, with the efficiency of toluene removal and ozone degradation maintained at 64.1% and 62.7%, respectively. Based on SEM characterization, the MnOx–Al2O3 aerogel demonstrated low MnOx agglomeration. From XPS and NH3-TPD analyses, it was found that the catalyst had a high content of Mn3+/Mn, Oβ/O, oxygen vacancies and acid sites, which was positively related to ozone degradation. Among them, an increase in the number of weak acid and moderately strong acid sites could prolong the life of active oxygen, which was the key to promoting the deep oxidation of toluene effectively. In addition, the MnOx–Al2O3 aerogel exhibited remarkable load-adjustability and humidity resistance. Therefore, the development of aerogel catalysts for catalytic ozonation of toluene is an effective strategy to alleviate the current ozone catalyst problem. [ABSTRACT FROM AUTHOR]

Adsorbent materials with high absorption capacity, stable mechanical properties, greenness and economy are highly desirable for efficient removal and recovery of oil from wastewater. Herein, an ultralight, low-cost and reusable hydrophobic aerogel of cellulose acetate/polyethylene oxide hybrid nanofibers was developed through thermal crosslinking and organosilicon modification. Through thermal crosslinking and an ice crystal template, a hierarchical pore structure was obtained which endowed the aerogel with mechanical stability and oil-absorption capacity. In addition, the structure was further strengthened after chemical vapor deposition of methyl trichlorosilane and good hydrophobicity (contact angle of 135.5°) can be realized. The surface-modified aerogel presented an ultralow density (8.74 mg cm−3), excellent resilience (completely recover to its original height after 50 compression cycles), high absorption capacity (weight gain of 63–128 g g−1) and reusability. Therefore, nanofibrous aerogels with outstanding compressive resilience and reusability make it promising to meet the increasing demand in the field of oil pollution cleaning. [ABSTRACT FROM AUTHOR]

In this study, a novel sodium alginate–streptomycin sulfate composite aerogel (Alg–Stre) was synthesized by using chemical grafting and vacuum freeze-drying techniques to remove heavy metal ions from water. The experimental results show that the prepared Alg–Stre can effectively remove heavy metal ions such as Pb2+ and Cu2+ from water. Among these ions, Alg–Stre demonstrated the best removal effects for Pb2+ (99.8%, 0.1 mM) and Cu2+ (94.6%, 0.1 mM) in water. The utmost adsorption capacities of Alg–Stre for Pb2+ and Cu2+ are 280 mg g−1 and 160.2 mg g−1, respectively, which are competitive with those of most reported Pb2+- or Cu2+-sorbents. In addition, the adsorption abilities of Alg–Stre for Pb2+ and Cu2+ remained stable in solution pH values of 3.0 to 6.0 and at ambient temperatures of 20 °C to 50 °C. The simple preparation process, high removal efficiency, suitability for different environments and conditions, and recyclability of Alg–Stre confirm the broad application prospects of this material in the field of sewage disposal. [ABSTRACT FROM AUTHOR]

With increasing attention on environmental impacts and sustainable development, the conversion of underutilised bagasse (BG) or low-value fibre waste into biosorbents has considerable potential applications. In this study, BG carboxymethyl cellulose (BGCMC) with a high degree of substitution (DS) was prepared by controlling the ratio of monochloroacetic acid (MCA) and sodium hydroxide to BG cellulose. BGCMC aerogels (BCGel) were obtained using the crosslinking reaction of citric acid (CA) with hypophosphite sodium (HPS) as a catalyst. The adsorption results were more suitable to be described by the Langmuir isotherm (R2 > 0.99), with maximum adsorption capacities of BC3Gel for Pb(II) and MB of 353.36 and 1260.9 mg g−1, respectively. Additionally, after treatment with 50% alcohol or 0.05 M EDTA solution, BCGel exhibited satisfactory removal performance even after five regeneration cycles. X-ray photoelectron spectroscopy (XPS) and energy-dispersive X-ray spectrometry (EDS) results demonstrated that cationic exchange and electrostatic interaction were the main Pb(II) and MB adsorption mechanism. The adsorption mechanism of BCGel for pollutants involves the interaction of multiple adsorption forms. The excellent Pb(II) and MB adsorption capacities of BCGel provide another avenue for the recycling of waste BG in the wastewater treatment field. [ABSTRACT FROM AUTHOR]

Mixed perovskites have vast industrial potential, but some challenges (i.e., aggregation and chemical instability) limit their applications. Herein, a novel environment-friendly carbon aerogel (CAg) synthesized from sodium alginate (SA) was used as a precursor to create a double-B-site perovskite/carbon aerogel hybrid adsorbent ((Sr0.7Mn0.3Co0.5Fe0.5O3-δ)/CAg) (DB-perovskite/CAg hybrid). The adsorbent was extensively characterized via different techniques, including X-ray photoelectron spectroscopy and Fourier transform infrared (FTIR) spectroscopy. The removal efficiency for crystal violet (CV) and acid yellow 17 (AY17) was conducted over various pH, adsorbent/adsorbate dosages, and reaction times in an aqueous system. The maximum adsorbed concentration (Qmax) recorded by 206 mg g-1 and 113 mg g-1 for CV and AY17, respectively, and compared to the performance of only DB-perovskite (114 mg g-1 and 59 mg g-1), respectively. The adsorption site energy distribution was studied by applying the density functional theory (DFT). The adsorption on the DB-perovskite/CAg hybrid was significantly regulated by pH change. The cooperative metal active/Lewis acid sites of the DB-perovskite/CAg adsorbent led to a faster and higher adsorption capacity toward CV and AY 17. The doping of Mn indicated a synergistic effect in improving the adsorption of either dye through the introduction of abundant active sites and strengthening of metal-functional groups (-C-O-C, -COOH, and C-OH/O-H)-p aromatic bonding, confirmed by DFT calculations. [ABSTRACT FROM AUTHOR]

Marine oil leakage and toxic chemical discharge accidents have occurred frequently, leading to serious water pollution problems. Thus, effective treatment of oily wastewater is imminent. Carbon aerogels are widely used for oil/water separation because of their unique structural properties. Herein, a carbon nanosphere aerogel (MCA) with abundant pores and magnetic response was synthesized using magnetic carbon nanospheres as precursors. The MCA demonstrates excellent adsorption properties for various oils and organic solvents (43.82–83.58 g−1) and good reusability. With good mechanical properties, the MCA could be recycled by simple extrusion. The adsorption capacity of the MCA was still 90.24% of the initial value after ten adsorption–compression cycles. In particular, importantly, the MCA could realize positioning adsorption and rapid recovery after adsorption saturation through a magnetic field. Large-scale oil in water could be separated and collected using a continuous oil/water separation device with the MCA as the filter. In short, the MCA is a promising adsorbent in oil spill treatment. This work has a good scientific research value and practical application prospect. [ABSTRACT FROM AUTHOR]

Global population growth and industrialization have exacerbated the nonrenewable energy crises and environmental issues, thereby stimulating an enormous demand for producing environmentally friendly materials. Typically, biomass-based aerogels (BAs), which are mainly composed of biomass materials, show great application prospects in various fields because of their exceptional properties such as biocompatibility, degradability, and renewability. To improve the performance of BAs to meet the usage requirements of different scenarios, a large number of innovative works in the past few decades have emphasized the importance of micro-structural design in regulating macroscopic functions. Inspired by the ubiquitous random or regularly arranged structures of materials in nature ranging from micro to meso and macro scales, constructing different microstructures often corresponds to completely different functions even with similar biomolecular compositions. This review focuses on the preparation process, design concepts, regulation methods, and the synergistic combination of chemical compositions and microstructures of BAs with different porous structures from the perspective of gel skeleton and pore structure. It not only comprehensively introduces the effect of various microstructures on the physical properties of BAs, but also analyzes their potential applications in the corresponding fields of thermal management, water treatment, atmospheric water harvesting, CO2 absorption, energy storage and conversion, electromagnetic interference (EMI) shielding, biological applications, etc. Finally, we provide our perspectives regarding the challenges and future opportunities of BAs. Overall, our goal is to provide researchers with a thorough understanding of the relationship between the microstructures and properties of BAs, supported by a comprehensive analysis of the available data. [ABSTRACT FROM AUTHOR]

The vigorous development of rare earth elements has become particularly important for the recycling and reuse of rare earth waste solutions. We use the specific coordination of the phosphate group and La3+ to recover and separate La3+ from secondary resources. First of all, cellulose nanocrystals should be phosphorylated by using phosphoric acid in an aqueous medium. Phosphoric acid groups are introduced to the surface of the cellulose nanocrystal, and then poly-N-isopropylacrylamide is introduced for modification. The purpose is to increase the mechanical properties of the material. The material was characterized by scanning electron microscope, transmission electron microscope, Fourier infrared spectroscopy, N2 adsorption–desorption analysis, and thermogravimetric and static adsorption experiments. The results of the static adsorption experiments show that the maximum adsorption capacity is 92.28 mg g−1 when the pH is 7.0. After recycling the material five times, the material could still have 87.24% of the maximum adsorption capacity. [ABSTRACT FROM AUTHOR]

At present, oil pollution on water has caused a disastrous and inestimable impact on the ecological environment and economic development. There is an urgent need for highly efficient materials for oil–water separation. There has been extensive research on Janus structural materials for use as novel oil–water separation materials. Herein, we developed an in situ construction strategy for the three-dimensional (3D) Janus structure based on a hydrophobic matrix and used a facile method to construct a 3D Janus structural cellulose aerogel with asymmetric wettability. Vacuum-assisted chemical vapor deposition technology was used to modify cellulose aerogel for the hydrophobic matrix. The hydrophilic layer was formed by coating dopamine with in situ polymerization on one side of the hydrophobic matrix. Moreover, the oxidative polymerization of dopamine in organic solution was investigated. The 3D Janus structural cellulose aerogel showed opposite wettability, with hydrophobicity on one side with a water contact angle of 142° and hydrophilicity on the other side. Due to the asymmetric wettability and interconnected network structure, the material achieved highly efficient separation performance for various mixtures of oil and water, even water-in-oil emulsion, with a penetration flux up to 3121 L m−2 h−1 and separation efficiency of 99.5%, driven only by gravity. The droplet size in the recycled filtrate was measured as 0.5–2 nm. In this work, we not only developed a novel, highly efficient, and environmentally friendly oil–water separation material for the field of water treatment, but we also provide a new construction strategy and a scientifically significant reference for Janus structural porous materials. [ABSTRACT FROM AUTHOR]

As it is a material obtained from natural resources, the functionalization and applications of cellulose have attracted interest recently. In this work, we reported a facile method for preparing bio-inspired functionalized corncob cellulose/rGO (CL/rGO) aerogels through freeze-drying technology. Measurements of the adsorption performance toward MB showed us that cellulose/rGO aerogels had good adsorption performance at pH = 7 and room temperature. In addition, we carried out adsorption–desorption cycling experiments to evaluate the stability and recyclability of CL/rGO aerogels. The good adsorption abilities endow the CL/rGO aerogels with great potential applications, e.g., they can be utilized for dye wastewater treatment. [ABSTRACT FROM AUTHOR]

Solar evaporation generation is a promising method for purifying high salinity water using renewable solar energy. However, the design for the efficient antifouling solar-thermal water evaporation of low-cost systems remains a challenge. Here, a simple, anti-oil-fouling and macroporous aerogel based on polyvinyl alcohol (PVA), sodium alginate (SA), and polyaniline (PANi) was prepared by an in situ polymerization and freeze-drying technique. Solar water evaporation experiments were performed on the aerogel under one-sun illumination. Because of the synergistic effects of the abundant macroporous structure, roughness of the surface, and hydrophilic polymeric matrix, the aerogel displayed high solar absorption, and superhydrophilic and underwater superoleophobic surface properties. As a result, under one-sun illumination, the aerogel had a maximum solar-thermal efficiency of 91.5% and an evaporation rate of 1.46 kg m−2 h−1. More importantly, the aerogel exhibited almost identical evaporation performance in oily wastewater and saline alkali water. After 25 cycles, the photothermal conversion efficiency was found to be 87% and the aerogel was still resistant to oil contamination. The high solar vapor generation rate and antifouling functionality make the macroporous aerogel a promising material for solar-thermal water desalination, even in oil-contaminated water. [ABSTRACT FROM AUTHOR]

In the face of increasingly severe electromagnetic wave (EMW) pollution, the research of biomass-based carbon materials due to the advantages of being green, renewable, environment-friendly, porous and light has become one of the most attractive topics. However, there is little research on the microstructure control of biomass-based materials. Herein, two kinds of chitosan-derived carbon aerogels (CAs) were prepared by adjusting the amount of chitosan and changing the pre-freezing method. Two morphologies of bamboo tube structure (BTS) and isolated island structure (IIS) were controlled by the growth speed and direction of ice crystals in a refrigerator and freeze dryer differently. The obtained samples with very low densities of 0.075-0.174 g cm-3 can bear 400 times their own weight. Furthermore, the unique layer spacing and porous characteristics make the infrared emissivity of IIS aerogels possess 0.545-0.709 at 20-300 °C with greater thermal insulation. In particular, the effective absorption bandwidth (EAB) of the IIS aerogel nearly contains the entire Ku band within the thickness of 1.0-1.4 mm, and the minimum reflection loss (RLmin) peaks appear to shift to the left compared with the IIS aerogel. Besides, the simulation results of radar cross-section (RCS) show that the IIS with a thickness of 1.4 mm can reduce the RCS by ~20.3 dB m² at 14.1 GHz. This study provides a reference for the study of eco-friendly chitosanderived carbon absorbers. [ABSTRACT FROM AUTHOR]

Facing the fast development of telecommunication technology, traditional electromagnetic wave absorbing materials are unable to meet the microwave shielding requirements in practical applications. Herein, a Ti3C2Tx MXene/rGO composite aerogel was synthesized by facile hydrothermal and freeze-drying treatment. The prepared aerogel shows a unique porous three-dimensional network structure, which is of great advantage in improving its microwave absorption capability. Mixing Ti3C2Tx and rGO adjusts the impedance match in the absorption process. When the weight ratio of Ti3C2Tx to rGO is 1 : 6, the minimum reflection value (RLm) reaches −53.49 dB at 17.0 GHz (thickness = 2.2 mm), and the corresponding effective absorption bandwidth is 4.4 GHz (from 13.6 GHz to 18.0 GHz). rGO nanosheets of large size could retard the oxidation of Ti3C2Tx to some extent. With its excellent microwave absorption performance, broad effective bandwidth, outstanding thermal resistance, and heat insulating properties, the composite aerogel has a great practical potential. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks stand as unique building blocks, bridging the gap between coordination chemistry and materials science. While significant advances have been made in their design, current efforts focus on expanding their pore size above the microporous regime and on their shaping into well suitable end use devices. For such a purpose, we herein explored the use of chitosan hydrogel microspheres as a mold to grow an extended network of MOFs, followed by CO2-supercritical drying to generate three-dimensional polysaccharide nanofibrils embedding entangled MOF nanoclusters. This strategy was found to be highly versatile, and allows for shaping HKUST-1, ZIF-8, ZIF-67 and Fe-BTC inside chitosan microspheres. The resulting lightweight aerogels display excellent activity for oxime oxidation, with HKUST-1 loaded on chitosan beads standing as the most promising. The virtues of supercritical drying were substantiated by comparing the catalytic activity of these aerogels with their xerogel analogues as well as pristine HKUST-1. Interestingly, moreover, the configuration of MOFs in chitosan beads precludes the metal from leaching and allows easy recovery of the catalyst from the medium and its possible recycling. [ABSTRACT FROM AUTHOR]

A novel cellulose-based aerogel was prepared by a chemical cross-linking reaction and hydrogen bonding between cellulose nanofibers (CNF), polyethylene glycol diglycidyl ether (PEGDE), and hyperbranched polyethyleneimine (HPEI). The obtained aerogel was employed as an adsorbent for the removal of Congo red (CR) dye. The aerogel morphology was examined by scanning electron microscopy (SEM), the chemical structure and thermal stability of aerogels were characterized by Fourier transform infrared (FT-IR) spectroscopy and X-ray photoelectron spectroscopy (XPS), and the thermal stability was determined using thermogravimetric analysis (TGA). The influences of contact time, pH value, concentration of dyes, and adsorptive selectivity on the adsorption capacity of the aerogels were investigated. The adsorption experiment showed that the aerogels were excellent adsorbents of CR due to their highly porous structure and the existence of abundant amine groups. Thermodynamic and kinetic studies showed that a pseudo-second-order equation (R2 > 0.9967) and Langmuir model (R2 > 0.9948) were more suitable for the adsorption of the aerogel. The maximum adsorption capacity for CR by the aerogel according to the Langmuir model was 2125.96 mg g−1. [ABSTRACT FROM AUTHOR]

The development of aerogel materials with high preparation efficiency, no pollution, and high adsorption efficiency is still an effective solution for water pollution caused by heavy metal ions. We propose a simple and efficient way to prepare composite aerogel with a porous network-like structure to adsorb copper ions. The new adsorbent (CTC) was prepared by impregnating cellulose nanofiber (CNF)/multi-walled carbon nanotubes (MWCNTs) aerogel directly into the chitosan solution. The influence of different experimental factors such as the concentration of impregnated chitosan solution, pH value, temperature, and contact time on the CTC adsorption effect was tested. The results showed that the adsorption of CTC reached equilibrium after 2 h. At 25 °C, when the pH value of the solution was four and the concentration of impregnated chitosan was 0.6 wt%, the maximum adsorption capacity was 46.05 mg g−1. CTC was expected to become a new environmentally-friendly adsorbent for copper ion adsorption due to its high adsorption efficiency and use of no toxic substances in the preparation process. [ABSTRACT FROM AUTHOR]

Interpolymer interactions play a vital role of determining the microstructure and properties of polymer aerogels. In terms of poly(vinyl alcohol) (PVA) aerogels, the conformation and behaviour of polymer chains in semidilute aqueous solutions make considerable contribution to the evolution of polymer matrixes during preparation. In this work, we investigated the microstructure of a group of PVA-based aerogels from the view of interactions between polymer chains. In PVA/poly(ethylene oxide) (PEO) aerogels, disordered microstructures were formed with the increase in PEO amount, owing to the existence of weak hydrogen bonds and some existing crystalline domains of PVA and PEO. PVA/poly(acrylic acid) (PAA) samples, presented straight stripe-shaped structures, because of the strong interactions between PVA and PAA. In PVA/carboxyl methyl chitosan (CM-CTS) aerogels, high density of stripe microstructures were observed, due to the rigid conformation of CM-CTS in water and few hydrogen bonds existed between PVA and CM-CTS. PVA/PAA aerogels possess compressive strength as high as 0.94 MPa. The porosity of the PVA/PEO aerogel reached 98.6%. Factors such as chain length and pH value of the precursor solutions on the microstructure of aerogels were also investigated. A possible forming mechanism was put forward from the view of interpolymer interactions, accordingly. Such way of tuning the microstructure of PVA-based aerogels may provide a new understanding with respect to the microstructure of polymer aerogels and pave new ways for the practical use of this versatile light material. [ABSTRACT FROM AUTHOR]

Different sorbents, including activated carbons, an Ag-aerogel, Ag-xerogels, an Ag-alumina, an Ag-zeolite, a Ag2S-polyacrylonitrile composite, and a carbon foam were investigated for static I2(g) loading at 71 °C for 56 d followed by 4.7 d of desorption. The iodine loadings were 630–1249 mg g−1 for activated carbons and 87–744 mg g−1 for other sorbents. [ABSTRACT FROM AUTHOR]

To meet practical application requirements, high specific energy and specific power and excellent cyclability are highly desired. Herein, we design and synthesize fine CuCo2O4 nanoparticles wrapped in a conductive rGO aerogel network as a robust conductive anode for Li-ion capacitors (LICs). The nanostructure of the resulting CuCo2O4/rGO composite provides a high capacity of 1285 mA h g−1 at a small current density of 0.1 A g−1. Moreover, the conductive anode was combined with an activated carbon (AC) cathode (denoted as CuCo2O4/rGO//AC) to construct high-performance LICs. The as-prepared device (CuCo2O4/rGO//AC LIC) exhibits capacitance of 49.5 F g−1 at 1 A g−1 and retained capacitance of 34.0 F g−1 when the current density increased to 4 A g−1, demonstrating outstanding rate performance. Excitingly, our fabricated CuCo2O4/rGO//AC LIC exhibits ultra-high specific energy and specific power (396 W h kg−1/8 kW kg−1) with excellent cyclability (∼100% retention after 16 000 cycles) for the first time. We demonstrate that a single LIC cell could light a blue LED with sufficient illumination for 100 s, opening the way to possible realistic applications. Additionally, based on the synergistic effect of the conductive rGO aerogel matrix and the downsized CuCo2O4 particles of the CuCo2O4/rGO anode, the superior electrochemical performance was attributable to increased conductivity and structural integrity during Li+ insertion/extraction. [ABSTRACT FROM AUTHOR]

Electrode materials for supercapacitors have been one of the crucial factors for the successful design of a renewable energy storage device. In this work, we present a bottom-up approach for the large-scale synthesis of three ternary hybrid aerogel nanocomposites, namely CMGA-1, CMGA-2 and CMGA-3, via the facile self-assembly of reduced graphene oxide (rGO), molybdenum disulfide (MoS2) and polymeric carbon nitride nanosheets derived from urea (TE_UCN). The three composites differ from each other only in the content of TE_UCN, with TE_UCN wt% of 33%, 60% and 71.4%, respectively, for CMGA-1, CMGA-2 and CMGA-3. All three composites possess a large surface area with a hierarchical porous structure. The influence of the wt% of TE_UCN in these composites on the electrochemical performance of the electrode was investigated using charge–discharge curves. When used as the electrode for supercapacitors, the nanocomposites exhibit pseudocapacitive behavior in NaCl solution. Comparing the three nanocomposites investigated here, CMGA-3 showed the best electrochemical performance, with a specific capacitance of 467 F g−1 and the ability to retain up to 80.4% of this capacitance even after 2000 cycles, demonstrating good stability and improved cyclic performance. The excellent supercapacitance of CMGA-3 is due to its high surface area (Brunauer–Emmett–Teller surface area = 432.3 m2 g−1) and low equivalent series resistance of 3.24 Ω. [ABSTRACT FROM AUTHOR]

The electrochemical carbon dioxide reduction reaction (eCO2RR) is a promising technology that uses electrical energy to catalytically reduce greenhouse gas-CO2, converting CO2 into high value-added products such as hydrocarbons and alcohols. However, due to the complexity of the eCO2RR, the activity and selectivity of the eCO2RR is highly dependent on the intrinsic catalytic activity of a catalyst with mass transportation-favorable morphology. Herein, silk fibroin-derived carbon aerogels (CAs) loaded with small amounts of Cu and Ag nanoparticles were synthesized. Based on the molar content of Cu, the catalysts were labeled SF-CuAg/CA-N (N = 20%, 40%, 60%, 80%). Among them, SF-CuAg/CA-40% showed a good FECO of 71% at −1.26 V vs. a reversible hydrogen electrode (RHE), and a significant current density of −15.77 mA cm−2 towards CO at −1.06 V vs. RHE, which is close to 2.6, 2.53 and 2.71 times those of SF-CuAg/CA-20% (−6.02 mA cm−2), SF-CuAg/CA-60% (−6.24 mA cm−2) and SF-CuAg/CA-80% (−5.82 mA cm−2). The SF-CuAg/CA-N composite materials prepared in this study provide new ideas for the design of highly efficient electrocatalysts for the eCO2RR. [ABSTRACT FROM AUTHOR]

We developed a novel electrospinning strategy, using choline chloride–lactic acid (ChCl–LA) deep eutectic solvent (DES) as an electrospinning solvent to produce lignin fiber aerogels (LFA). The novel strategy is sustainable and cost-effective because no toxic or flammable volatile organic solvents were used and the precursors and waste were designed to be recycled. The fabricated LFA has the appearance of a piece of cotton, and the specific mass was calculated and found to be as low as 3 mg cm−3 with a porosity of over 99.7%. After stabilization and carbonization at a high temperature, the LFA can transform into lignin-based carbon fiber aerogels (LCFA). The LCFA has a high specific surface area (580 m2 g−1) and conductivity, and can be used as an electrochemical electrode material. We made supercapacitor electrodes using the LCFA, the specific capacitance of which is 155 F g−1, much higher than that of commercial multi-wall carbon nanotubes (39 F g−1) at a current density of 0.5 A g−1. The LCFA also have a high electrochemical cycling stability. For the supercapacitor electrodes, only a 2% decrease was observed after 5000 cycles. Moreover, all waste in this work was recycled and reused five times to achieve electrospinning with almost no waste. [ABSTRACT FROM AUTHOR]

Hexavalent chromium (Cr(VI)) is an noxious and highly toxic heavy metal that presents a serious threat to human health if present even in low concentrations in drinking water. Photocatalytic reduction of Cr(VI) to its less toxic Cr(III) state is a potential strategy to combat Cr(VI) pollution, but the efficiency of the process is low, especially in the absence of hole scavenger organic reagents. To address this issue and prepare efficient photocatalysts for Cr(VI) removal from water, in this study, we explored Prussian blue (PB) as a co-catalyst for improving the photoreduction performance of different high surface area TiO2-based materials (titania or silica–titania nanoparticles and aerogels). The photocatalyst nanomaterials were surface-modified with nanocrystalline PB using the photodeposition route. The PB layer acts as an effective electron acceptor/mediator between the semiconductor photocatalyst and Cr(VI) species. All the PB-modified photocatalysts exhibit higher photocatalytic activity (up to 9 times faster) as compared to the unmodified photocatalysts towards reduction of Cr(VI). Importantly, the PB-modified photocatalysts exhibited high photocatalytic performance (98–99% reduction in 40 min for pH = 5.6 and in 10 min for pH = 3) without addition of organic reagents. The simple approach reported herein can be followed to prepare new PB-photocatalyst systems with improved photocatalytic performance towards Cr(VI) reduction and other target applications. [ABSTRACT FROM AUTHOR]

This study was performed to investigate the potential application of a chitosan (CS) and quinoa polysaccharide (QS) composite aerogel for the adsorption of dyes from water. The properties of the synthesized CSQS composite aerogel were characterized by Fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), the Brunauer–Emmett–Teller (BET) method, and X-ray photoelectron spectroscopy (XPS). Results showed that the CSQS composite aerogel possesses a porous, loose and flexible structure with a mesoporous nature and high hydrophobicity. Meanwhile, various factors such as the initial concentration, temperature, contact time, and pH have been investigated for evaluation of the optimum adsorption for the removal of Congo red (CR) and methylene blue (MB) in batch sorption experiments, and experimental results showed that the maximum adsorption capacity was found to be 342 mg g−1 for CR and 57.80 mg g−1 for MB under the optimum conditions. The adsorption kinetics of CR and MB on the CSQS composite aerogel were found to be well modeled by pseudo-second-order and pseudo-first-order kinetic models, respectively. In addition, the experimental equilibrium data were represented well by the Langmuir isotherm model. The results in this article demonstrated that the obtained aerogel is suitable for application in drinking water purification. The entire synthesis process of the CSQS aerogel is green and economical without additional need for toxic agents, which allows the process to greatly reduce the discharge of secondary pollution to the environment. The facile, scalable and general strategy presented here can be extended to the preparation of other polysaccharide-based aerogel materials, and has a good prospects for application in the removal of dyes from water. [ABSTRACT FROM AUTHOR]

Herein, fabrication of a functionalized graphene aerogel (f-GA) from a biomass (pear fruit)-derived graphene aerogel (GA) is described. Functionalization showed a prominent effect that results in the improved adsorption capacity of f-GA compared to GA, and even better (∼more than double) than commercially available activated carbon (AC). f-GA has been studied for the removal of three different model pollutant dyes, namely crystal violet (CV), methylene blue (MB), rhodamine B (RhB) and their mixtures, along with it also being used for dye removal from unknown real industrial samples. Moreover, a detailed comparative analysis showed the adsorption capacity of f-GA towards CV, MB, and RhB has been improved up to ∼6, ∼7, and ∼10 times, respectively, compared to that of control GA. The recyclability of f-GA was also tested: it works for five cycles without losing its apparent performance. [ABSTRACT FROM AUTHOR]

Nitrogen self-doped mesoporous carbon is synthesized from a novel polybenzoxazine and used as an electrode for supercapacitor applications. Two different types of carbon are derived from the same polybenzoxazine, which is synthesized from apigenin, furfuryl amine, and formaldehyde. Carbon derived from calcination is denoted as APFC-N and the other carbon type derived from an aerogel is denoted as APFC-G. The surface areas of APFC-N and APFC-G are found to be 248 and 635 m2 g−1, respectively. The pore size of APFC-G carbon is in the range of 2–5 nm, which is a suitable pore size for use as an electrode in electrochemical applications. The electrochemical properties of carbon obtained from the aerogel method (APFC-G) show good performance for supercapacitor applications with a specific capacitance of 120 F g−1 at a current density of 0.5 A g−1. At a low voltage scanning rate of <50 mV s−1, a better rectangular shape is observed in the cyclic voltammogram of APFC-G. The impedance spectra of both carbon types agree well with the results of capacitance and the cyclic voltammogram analyses. Also, good cycling stability is retained, even after 25 000 continuous charge–discharge cycles. [ABSTRACT FROM AUTHOR]

Organic–inorganic hybrid materials have attracted extensive attention in photocatalysis. In this work, p-aminobenzoic acid (PABA) grafted TiOx semiconductive aerogels were successfully prepared and characterized by N2 physisorption, FT-IR, SEM, TG, XPS, UV-vis DRS, PL, etc. The aerogels showed strong absorption of visible light. The absorption edges of the aerogels gradually red shifted with the increase of the grafting amount of PABA. Meanwhile, the porosity of the aerogels could also be changed with the composition. When the molar ratio of the grafted PABA to Ti was 0.56, the aerogel had a BET surface area of 264.1 m2 g−1, the average pore size was 7.7 nm, and the pore volume was 0.46 cm3 g−1. Correspondingly, the aerogel had a narrow band gap of 2.07 eV with a low PL intensity. Its conductivity was 0.0085 μS mm−1. Photocatalytic reduction of CO2 was carried out in 150 mL of 0.2 M ethylenediamine (EDA) aqueous solution under irradiation by a 300 W Xe lamp. The methanol yield reached 4090 μmol g-cat−1 within 4 h of irradiation. Comparatively, the methanol yield over the NH2-MIL-125(Ti) 2040 μmol g-cat−1. [ABSTRACT FROM AUTHOR]

Unsymmetrical dimethylhydrazine (UDMH) contaminated waste gas and related intermediates pose a great threat to human health. TiO2–reduced graphene oxide aerogel (rGA) samples with different graphene content levels were synthetized and characterized for the degradation of UDMH. The effects of GO content, humidity, and temperature were investigated under UV and VUV light, with highest UDMH conversion values of 68% and 95%, respectively. Compared with pure TiO2, the enhanced degradation activity of TiO2–rGA under UV light can be attributed to a synergetic effect between absorption and photocatalysis, while the high UDMH conversion under VUV light relies on photolysis and ozonation. The high oxygen-containing group content, rather than a high SSA, and electron trapping by graphene are key factors determining the outstanding performance of TiO2–rGA with 80 mg of GO. The prepared TiO2–graphene aerogels are promising for the degradation of gas-phase UDMH. [ABSTRACT FROM AUTHOR]