Large Pore Research Articles

Preparation and modification of PVDF membrane via VIPS method for membrane distillation

Membrane distillation (MD) is a promising technology for treating high-salinity mine water. However, MD membranes are known to have low membrane flux and are prone to fouling. In this study, we used the cost-effective and controllable vapor-induced phase separation (VIPS) technology to prepare polyvinylidene difluoride (PVDF) membranes, replacing the traditional immersion precipitation method and optimizing the membrane structure by including LiCl and acetone as porogen in the casting solution. The results showed that the membrane prepared using the VIPS method exhibited a highly open interconnected porous surface. Unlike traditional MD membranes with a dense epidermal layer and large finger-like pores, these optimized membranes had a symmetrical and uniform internal structure, leading to a high flux of 8.62 kg·(m2·h)−1 during direct contact membrane distillation testing. Different porogens produced varied results on the VIPS process and varying effects on membrane structure. The use of LiCl promoted the formation of PVDF β-phase, resulting in a decrease in the number of spherical nodules on the membrane surface, as well as improved density and smoothness. Consequently, this reduced fouling risk during membrane distillation while slightly decreasing membrane flux. On the other hand, acetone rapidly evaporated during the VIPS process, facilitating pre-gelatinization and α-phase formation of PVDF. This concurrent effect effectively restricted excessive nodule growth on the membrane surface, endowing the membrane with antifouling capabilities while preserving high flux.

Reverse Separation of Carbon Dioxide and Acetylene in Two Isostructural Copper Pyridine‐Carboxylate Frameworks

Separating acetylene from carbon dioxide is important but highly challenging due to their similar molecular shapes and physical properties. Adsorptive separation of carbon dioxide from acetylene can directly produce pure acetylene but is hardly realized because of relatively polarizable acetylene binds more strongly. Here, we reverse the CO2 and C2H2 separation by adjusting the pore structures in two isoreticular ultramicroporous metal−organic frameworks (MOFs). Under ambient conditions, copper isonicotinate (Cu(ina)2), with relatively large pore channels shows C2H2‐selective adsorption with a C2H2/CO2 selectivity of 3.4, whereas its smaller‐pore analogue, copper quinoline‐5‐carboxylate (Cu(Qc)2) shows an inverse CO2/C2H2 selectivity of 5.6. Cu(Qc)2 shows compact pore space that well matches the optimal orientation of CO2 but is not compatible for C2H2. Neutron powder diffraction experiments confirmed that CO2 molecules adopt preferential orientation along the pore channels during adsorption binding, whereas C2H2 molecules bind in an opposite fashion with distorted configurations due to their opposite quadrupole moments. Dynamic breakthrough experiments have validated the separation performance of Cu(Qc)2 for CO2/C2H2 separation.

Experimental study on long-term impermeability of recycled aggregate concrete mixed with crystalline admixture and waste glass powder

The impermeability of recycled aggregate concrete (RAC) presents challenges for underground engineering, particularly concerning its larger pore. Combining crystalline admixture (CA) with waste glass powder (WGP) offers a feasible solution to enhance impermeability. To understand the collaborative mechanism of CA and WGP in improving RAC impermeability and establish an accurate mixture ratio, we conducted compressive strength tests and a series of permeability tests on WGP and CA modified recycled aggregate concrete (WRC). These tests involved different CA contents (0%, 1%, and 2%) and varying WGP replacement rates (0%, 10%, 20%, and 30%). Our findings indicated that when the WGP substitution rate exceeds 10%, the strength of the WRC decreases by approximately 23%. In contrast, the overall decline is about 5% when the CA content increases from 0% to 2%. Therefore, the WGP emerges as the primary factor influencing the compressive strength of WRC. Meanwhile, The WGP and CA play a major role in enhancing the short-term and long-term impermeability of WRC, respectively. Additionally, When the WGP substitution rate increases from 0% to 30% on same CA content, the RC increases by approximately 2%, indicating that elevated WGP content enhances the effectiveness of CA. Finally, the optimal combination to improve the impermeability of WRC is 10% WGP substitution and 1% CA content. Microscopic tests analyses show that under the influence of CA and WGP, C–S–H gel, C-A-S-H gel, and Ettringite are produced inside the WRC, effectively blocking pores and cracks, thus improving the specimen's impermeability. This research not only holds the potential to elevate impermeability but also offers a solution to the issue of waste glass accumulation, contributing to global sustainable development.

Stimuli-responsive photoluminescent and structural properties of MIL-53(Al) MOF for sensing applications

Metal–organic frameworks (MOFs) are an intriguing group of porous materials due to their potential influence on the development of indispensable technologies like luminescent sensors and solid-state light devices, luminescent multifunctional nanomaterials. In this research work we explored MIL-53(Al), an exceptional class of MOF that, along with guest adsorption, undergoes structural transitions exhibiting breathing behavior between narrow pore and large pore under temperature and mechanical stress. Therefore, we opted for the time resolved luminescence and FT-Raman spectroscopy to investigate the mechanochromic and thermochromic response of this material under external stimuli. Intriguingly, when subjected to temperature changes, MIL-53(Al) exhibited a ratiometric fluorescence behavior related to the reversible relationship of photoluminescence emission intensity with respect to temperature. Moreover, under higher mechanical stress MIL-53(Al) displayed turn-on behavior in emission intensity, hence offering a thrilling avenue for the application in mechanically deformed-based luminescent sensors and ratiometric fluorescence temperature sensors.

Effect of silica fume type on rheology and compressive strength of geopolymer mortar

Silica fume (SF) is widely used in the developing of high-performance geopolymer systems. Previous studies have shown that using different types of SF may have different influences on the performance of geopolymers. What are the key factors (affecting the properties of geopolymers) still need to be clarified? This paper investigated the effects of three types of silica fume (SF1− SF3) with various silica contents (98.0%, 94.7% and 53.1%) and particle sizes (D50: 3.3 μm, 3.1 μm and 11.8 μm) on the rheology and compressive strength of alkali-activated calcium alumina cement (CAC)/fly ash mortar. The incorporation of SF can significantly increase the plastic viscosity. The increase in plastic viscosity was due to the ball-bearing action of the spherical SF particles, which reduced the friction between the particles under shearing. Replacing 20% of the fly ash with SF1 and SF2 improved the compressive strength of geopolymer mortars while the incorporation of SF3 decreased the compressive strength at the same replacement ratio. Inductively coupled plasma (ICP) spectrometry results indicated that the amorphous silica in the SFs was dissolved in an alkali solution. Activators with high concentrations of monomer and dimmer silicon groups may promote the reaction between precursors and activators. The formation of additional aluminosilicate gels reduced the amount of large capillary pores (500 nm to 1000 nm), leading to improved strength. The incorporation of coarse SF3 introduced extra voids in the mixture, as suggested by calculations of packing density, leading to reduced strength.

Compressive strength and microscopic mechanism of nanosilica modified recycled aggregate mortar

Due to low density, large pores, and numerous cracks, recycled aggregate mortar has defects of lower fluidity and lower strength compared to natural aggregate mortar. In order to modify inherent defects of recycled aggregates, nanosilica (NS) with different dosages (0%, 0.6%, 1.2%, 1.8%, 2.4% and 3%) was added to recycled aggregate mortar (RNC), and 40% natural sand in RNC was replaced by recycled aggregates. Then consistency test, compressive strength test and microscopic tests (SEM, EDS and XRD) were conducted to investigate working performance and microscopic mechanism. It was found that the addition of NS can improve the flowability of RNC, and the consistency value reaches the maximum (53 mm) while NS content is 2.4%, which increases by 14% comparing to the specimen without NS. The compressive strength of RNC increases and decreases with increasing NS content in the ranges of 0–1.8% and 1.8–3% respectively, and compressive strength is 3.3 and 5.9 MPa at curing ages of 7 d and 28 d respectively while NS content is 1.8%, which increase 50% and 14% comparing to the specimen without NS. Meanwhile, the consistency value of the specimen with NS content of 1.8% is 51 mm, which is close the maximum value corresponding to NS content of 2.4%. For that, 1.8% is suggested as the optimal content of NS. Moreover, the addition of NS can reduce the brittleness index and mechanical damage degree, and enhance the energy absorption effect. Microscopic analysis reveals that NS can not only fill the inherent cracks and pores of recycled aggregates, but also promote cement hydration reaction, and more hydration products (C-S-H) can efficiently reduce the cracks and pores of recycled aggregates. It is believed that the finds of this paper can provide theoretical support for the application of recycled aggregates in practical engineering.

Preparation of Single-Helical Curdlan Hydrogel and Its Activation with Coagulation Factor G

β-1,3-glucans are a kind of natural polysaccharide with immunomodulatory, antitumor, and anti-inflammatory properties. Curdlan, as the simplest linear β-1,3-glucan, possesses a variety of biological activities and thermogelation properties. However, due to the complexity and variability of the conformations of curdlan, the exact structure–activity relationship remains unclear. We prepare a chemically crosslinked curdlan hydrogel with the unique single-helical skeleton (named S gel) in 0.4 wt% NaOH at 40 °C, confirmed by diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS). X-ray diffractometry (XRD) data show that S gel maintains the single-helical crystal structure, and the degree of crystallinity of the S gel is ~24%, which is slightly lower than that of the raw powder (~31%). Scanning electron microscopy (SEM) reveals that S gel has a continuous network structure, with large pores measuring 50–200 μm, which is consistent with its high swelling property. Using the 13C high-resolution magic angle spinning nuclear magnetic resonance (HRMAS NMR) method, we determine that most of the single-helical skeleton carbon signals in the swollen S gel are visible, suggesting that the single-helical skeleton of S gel exhibits fascinating mobility at room temperature. Finally, we reveal that the binding of S gel to coagulation Factor G from tachypleus amebocyte lysate increases and saturates at 20 μL tachypleus amebocyte lysate per mg of S gel. Our prepared S gel can avoid the transformation of curdlan conformations and retain the bioactivity of binding to coagulation Factor G, making it a valuable material for use in the food industry and the pharmaceutical field. This work deepens the understanding of the relationship between the single-helical structure and the activity of curdlan, promoting the development and application of β-1,3-glucans.

Synergistic effect of combining UiO-66 nanoparticles and MXene nanosheets in Pebax mixed-matrix membranes for CO2 capture

The use of membrane-based gas separation has garnered significant interest owing to its cost-effectiveness, outstanding performance and positive environmental impact. The performance of gas separation membranes can be considerably enhanced by mixed-matrix membranes (MMMs), but poor interactions between additives and membrane matrix and the agglomeration of highly incorporated fillers in MMMs limit the benefits of overcoming tradeoff effect. Therefore, the regulation of the state of fillers in membrane matrix is a crucial indicator in the development of MMMs. In this study, MXene (Ti3C2Tx) nanosheets and UiO-66 nanoparticles were prepared and used as fillers, in combination with a Pepax-1657 matrix, to synthesize MMMs for CO2-gas separation. As-prepared MMMs were used for the separation; the large pores (0.5–0.6 nm) of UiO-66 served as a highway to enhance CO2 permeability, and MXene nanosheets were used as selective channels to achieve high selectivity via the terminal polar surface groups of MXene. The combination of UiO-66 and MXene not only enhanced the selectivity, but also increased the solubility and diffusivity via selective CO2 adsorption and the tortuous pathway provided by MXene nanosheets. As a result, adding MXene and UiO-66 to Pebax helped MMMs overcome the tradeoff effect. MMMs loaded with 10 wt% MXene/UiO-66 exhibited a CO2 permeability coefficient of 214.6 Barrer and an ideal CO2/N2 selectivity coefficient of 102. Dual filler-containing MMMs showed enhanced CO2 permeability coefficient and CO2/N2 selectivity in comparison to pristine Pebax and individual nanofiller-added membranes. In this study, the combination of 2D MXene and UiO-66 nanoparticles exerted a synergistic effect in improving the CO2 separation efficiency of MMMs. This research provides a novel route for fabricating high-performance MMMs in the separation of CO2.

MOF‐derived Porous Carbon for Zinc‐ion Hybrid Capacitors with Ultra‐high Energy Density and Long Cycling Life

Zinc‐ion hybrid capacitors (ZHC) have been considered as emerging sustainable electrochemical energy storage devices. They integrate the benefits of high‐energy density of aqueous zinc ion battery (ZIB) with high‐power density of supercapacitor (SC). Metal‐organic frameworks (MOFs) have been widely used to design electrode materials for portable devices, especially in some energy storage fields because of their large specific surface area and adjustable pore structures. In this work, we prepare porous Mn3O4/C nanosheets with Mn‐BDC as a precursor. The assembled device delivers a specific capacitance of 155.3 mAh g‐1 at a current of 3 A g‐1 and keeps a retention rate of 97.7% after 10,000 cycles. Moreover, it provides an energy density of 464.5 Wh kg‐l at a power density of 100 W kg‐1.

Fabrication of lignosulfonate-derived porous carbon via pH-tunable self-assembly strategy for efficient atrazine removal

Herein, a straightforward protocol was developed for the one-pot synthesis of N-doped lignosulfonate-derived carbons (NLDCs) with a tunable porous structure using natural amino acids-templated self-assembly strategy. Specifically, histidine was employed as a template reagent, leading to the preparation of 10-NLDC-21 with remarkable characteristics, including the large specific surface area (SBET = 1844.5 m2/g), pore volume (Vmes = 1.22 cm3/g) and efficient adsorption for atrazine (ATZ) removal. The adsorption behavior of ATZ by NLDCs followed the Langmuir and pseudo-second-order models, suggesting a monolayer chemisorption nature of ATZ adsorption with the maximum adsorption capacity reached up to 265.77 mg/g. Furthermore, NLDCs exhibited excellent environmental adaptability and recycling performance. The robust affinity could be attributed to multi-interactions including pore filling, electrostatic attraction, hydrogen bonding and π-π stacking between the adsorbents and ATZ molecules. This approach offers a practical method for exploring innovative bio-carbon materials for sewage treatment.

Double-layered cellulosic interfacial evaporator via upcycling of waste cotton fabrics for efficient solar desalination

Constructing efficient solar-driven interfacial evaporators (SDIEs) derived from biomass or waste stream materials (e.g., cellulose) is still challenging due to their less elaborate porous structure. Herein, we showed waste cotton fabrics could be dissolved and regenerated into aerogels with tunable channels suitable for constructing a double-layered SDIE. The evaporator consists of a polypyrrol-coated top layer featuring vertical channels with larger pores and a hydrophilic bottom layer featuring smaller pores. With such design, the photothermal and pro-evaporative capabilities of the top layer was coupled with the strong capillary effect of the bottom layer to drive effective evaporation. A desirable evaporation rate of 3.20 kg m−2h−1, 80.0% solar-to-vapor conversion efficiency under 1 sun irradiation, and a reduced evaporation enthalpy of 962 J g−1 was achieved. The SDIE also exhibits high purification efficiency (exceeding 99%) during long-term operation of seawater desalination and shows great potential in treatment of waste streams of high salinity dyeing effluent. In summary, this work demonstrates a case of upcycling waste cotton fabrics for water desalination.

Direct carbonation of porous materials produced from self-hardened paper mill fly ash

A high-Ca fly ash generated from a paper mill using a fluidized bed boiler was used as the potential medium to sequester CO2 via the direct carbonation process. In this study, the fly ash samples were exposed to accelerated carbonation to produce hardened pastes. The influence of the porosity controlled by the amount of foam in the matrix for maximizing CO2 sequestration was determined. The effect of porosity on carbonation was evident. The samples prepared with 40 % foam and a water-to-fly ash ratio of 0.79 recorded porosities of 56.1 % (carbonated) and 66.8 % (naturally carbonated (NC)) with the lowest mechanical strength of 2.1 and 1.1 MPa, respectively. These naturally carbonated (NC) samples have been cured naturally without using high CO2 pressure. Meanwhile, the samples prepared with 10 % foam and a water-to-fly ash ratio of 0.5 recorded porosities of 41.1 % (carbonated) and 52.9 % (NC) with the highest strength at 10.2 and 4.6 MPa, respectively. The highest carbonation efficiency determined by thermogravimetric analysis was obtained from the carbonated samples with 40 % foam. Scanning electron microscopy–energy-dispersive spectroscopy depicted the areas with high Al/Si content but low Ca–O content (dark areas) and carbonated areas with high Ca–O content (bright areas). Mercury intrusion porosimetry was used to determine the pore size distribution, whereby the samples were dominated by large capillary pores, resulting in their high porosity in this study.

Advanced g-C3N4 and bimetallic FeNi-BTC integration with carbon quantum dots for removal of microplastics and antibiotics in aqueous environments

In this study, a novel approach was undertaken by integrating the photocatalyst graphite carbon nitride (g-C3N4) with FeNi-BTC (BTC: Benzene-1,3,5-tricarboxylic acid) and carbon quantum dots (CQDs) to enhance the interaction between semiconductors. The g-C3N4/CQD/FeNi-BTC material was synthesized using an environmentally friendly method that eschews the use of harmful solvents, using a combination of hydrothermal and microwave methods. The resulting material boasts a large pore volume (1.192 cm3g–1), a high surface area (1090 m2g–1), a small particle size (40–60 nm), and the capability to absorb visible light (2.27–2.52 eV). This material demonstrates remarkable efficiency in adsorbing microplastics, including polystyrene and polyethylene terephthalate (PET), at a concentration of 1200 mg L–1, achieving nearly 100% efficiency in just 45 minutes. Additionally, the g-C3N4/CQD/FeNi-BTC material shows significant effectiveness in degrading tetracycline, with an efficiency of 98.28% after 90 minutes of exposure to visible light irradiation. The study extensively explores factors that influence the pollutant treatment process, including time, concentration, pH value, temperature and the water source. The process of adsorbing MP on g-C3N4/CQD/Fe8Ni2BTC material is mainly physical adsorption, following pseudo-second-order reaction kinetics, endothermic reaction (ΔH > 0), and the adsorption process occurs spontaneously (ΔG < 0). This comprehensive approach provides valuable insights into the potential of the g-C3N4/CQD/FeNi-BTC material for treating pollutants in a range of aquatic environments, highlighting its versatility and effectiveness in environmental remediation.

BIO-ADSORPTION OF HEAVY METAL ION FROM WATER USING ACTIVATED CARBON

The discharge of effluent polluted with heavy metals have become a growing concern for researchers around the world. This study evaluated the removal efficiency of commercial activated carbon and rice husk activated carbon as adsorbents for the removal of copper ion in water. A nominal size of 1 mm was obtained after sieving the Rice Husk, washed with distilled water, dried in an oven t at 80 ℃ for 12 hours, and pyrolyzed in a furnace at 550 ℃ for 30 minutes. The chars produced were later air-dried and then activated with lemon juice. The Rice Husk Activated Carbon (RHAC) and Commercial Activated Carbon (CAC) purchased from the market were both subjected to the following analyses: bulk density, X-ray Fluorescence (XRF), Brunauer–Emmett–Teller (BET), Scanning Electron Microscope (SEM) and Energy Dispersive X-ray (EDX) in order to characterise the adsorbents and to understand their suitability for the removal of copper ion in water. One of the properties of an adsorbent is large pores which is exhibited by the activated carbons as revealed by the SEM analysis. Likewise, the XRF and EDX analyses confirmed that the adsorbents had larger proportion of Silica (50.1 – 50.25%), Carbon (60.06 – 84.87 wt .%) and Oxygen (15.13 – 21.60 wt. %) which is a property of a good adsorbent. BET analysis showed that the surface areas of the rice husk activated carbon and the commercial activated carbon were 998.35 and 1208.25 m2/g, respectively. The bulk densities of the rice husk activated carbon and the commercial activated carbon were 0.3325 and 0.2812 g/cm3, respectively. The maximum removal efficiency using RHAC was observed at 60 ℃ and 120 minutes at 83.96 and 89.21 %, respectively while for CAC the maximum removal efficiency was observed at 60 ℃ at 84.61 % and 30 minutes at 83.3 %. Initial concentration of 20 mg/l was observed to have the highest removal efficiency for the two activated carbon specimens. The modelled effect of initial concentration, temperature and contact time on removal efficiency yielded R2 values of 1, 0.918; 1,1 and 1,1 respectively for the CAC and RHAC.

Displacement Mechanism and Flow Characteristics of Polymer Particle Dispersion System Based on Capillary Bundle Model

During the development of oil reservoirs, a rapid increase in water cut following reservoir flooding leads to inefficient or ineffective circulation of injected water, rendering a significant portion of the remaining oil in the reservoir inaccessible. The displacement method using polymer particle dispersion systems effectively solves the issue of rapid water breakthrough in oil reservoirs. Owing to the particle phase separation phenomenon, polymer particles can selectively penetrate into the larger pores where water circulation is inefficient, enhance their flow resistance, and thereby achieve equilibrium displacement along with an increased swept volume. This paper investigates the heterogeneous distribution of polymer particles within a porous medium, incorporates the red blood cell dendrite concentration distribution theory from biological fluid mechanics, and develops a mathematical model to delineate the viscosity characteristics of polymer particle dispersion systems, taking into account the phase separation phenomenon. Building on this foundation, it formulates a capillary bundle model for the polymer particle dispersion system specifically designed for oil displacement and proceeds to determine its relative permeability curve. Simulation outcomes reveal that at a water saturation level of 0.063, the concentration of polymer particles in fractured large pore capillaries is markedly elevated, yet capillaries with a pore size under 26 μm remain devoid of polymer particles. With the increase of water saturation, the concentration of polymer particles in large pore capillaries reduces, whereas it progressively augments in medium pore capillaries. Upon reaching a peak water saturation of 0.751, capillaries smaller than 18 μm are entirely free of polymer particles. These findings suggest that the heterogeneous distribution of polymer particles markedly inhibits the percolation capabilities of the dispersed system following a water phase breakthrough, facilitating the entry of more dispersion into oil-laden capillaries and thus enhancing the flow capacity of the oil phase.

Cu-BTC Derived Mesoporous CuS Nanomaterial as Nanozyme for Colorimetric Detection of Glutathione.

In this paper, Cu-BTC derived mesoporous CuS nanomaterial (m-CuS) was synthesized via a two-step process involving carbonization and sulfidation of Cu-BTC for colorimetric glutathione detection. The Cu-BTC was constructed by 1,3,5-benzenetri-carboxylic acid (H3BTC) and Cu2+ ions. The obtained m-CuS showed a large specific surface area (55.751 m2/g), pore volume (0.153 cm3/g), and pore diameter (15.380 nm). In addition, the synthesized m-CuS exhibited high peroxidase-like activity and could catalyze oxidation of the colorless substrate 3,3',5,5'-tetramethylbenzidine to a blue product. Peroxidase-like activity mechanism studies using terephthalic acid as a fluorescent probe proved that m-CuS assists H2O2 decomposition to reactive oxygen species, which are responsible for TMB oxidation. However, the catalytic activity of m-CuS for the oxidation of TMB by H2O2 could be potently inhibited in the presence of glutathione. Based on this phenomenon, the colorimetric detection of glutathione was demonstrated with good selectivity and high sensitivity. The linear range was 1-20 μM and 20-300 μM with a detection limit of 0.1 μM. The m-CuS showing good stability and robust peroxidase catalytic activity was applied for the detection of glutathione in human urine samples.

Superior Heat and Mass Transfer Performance of Bionic Wick with Finger-like Pores Inspired by the Stomatal Array of Natural Leaf.

The thermal management of electronics has gained significant attention, with loop heat pipes (LHPs) emerging as an attractive solution for heat dissipation. The heat transfer performance of LHPs is influenced by the heat and mass transfer processes within the wick. However, designing the pore diameter of the wick is challenging due to the different requirements of flow resistance and capillary force. Specifically, the working fluid needs large pores to reduce resistance, while the liquid suction requires small pores to provide a large capillary force. To address this issue, we drew inspiration from the stomatal array of natural leaves used for transpiration and developed an alumina ceramic bionic wick with finger-like pores using the phase-inversion tape casting method. The finger-like pores in the wick resemble the straight hole structure of stomata, which increases the gas-liquid interface area within the wick. This design allows for timely discharge of water vapor generated by boiling, thereby reducing mass transfer resistance. Additionally, numerous micrometer-sized small pores surrounding the finger-like pores provide sufficient capillary force to replenish liquid for the gas-liquid evaporation interface. Experimental results demonstrate that the introduction of finger-like pores in the wick increases gas and water permeabilities by 2.4 and 5.2 times, respectively. Furthermore, the superior heat and mass transfer performance of the bionic wick was demonstrated with an LHP. This work effectively addresses the conflicting demands of capillary force and flow resistance, enhancing the heat transfer performance of LHPs, which holds great promise for addressing heat dissipation challenges in high power density electronic chips and has potential applications in aviation, aerospace, and microelectronics for efficient thermal management.

Aromatic‐rich oil production from catalytic co‐pyrolysis of pine sawdust and LDPE with bifunctional biochar by different preparation methods

AbstractBackgroundCatalytic co‐pyrolysis of biomass with waste plastics can produce high‐quality chemicals, making it a potential alternative to fossil fuels. The production of aromatic‐rich oil was achieved in this work by the catalytic co‐pyrolysis of pine sawdust and low‐density polyethylene (LDPE) using a series of biochar (BC) made using different preparation methods. Zinc chloride (ZnCl2) was employed to activate the BC during the preparation process, owing to its optimal activity for the co‐pyrolysis intermediates. The study compared the effects of BCs activated using different treatment methods on the yield and fractions of pine sawdust and LDPE co‐pyrolysis in a fast pyrolysis tube furnace at 650 °C.ResultsThe study indicates that the ZnCl2 BC, prepared from pine sawdust by fast pyrolysis (F‐AC), exhibited the best aromatic catalytic activity. The selectivity to aromatic hydrocarbons was 72.53%, and the content of BTEX (benzene, toluene, ethylbenzene, and xylene) was 32.17%.ConclusionThe Diels–Alder reaction and aromatization were made more effective due to the Zn sites and large pore structure in F‐AC. Using Fourier transform infrared, scanning electron microscopy and X‐ray photoelectron spectroscopy analysis, it was found that F‐AC contained more oxygen (O)‐containing groups in abundance, which improved its adsorption capacity for reaction intermediates. At the same time, the porous structure and high SSA of BC provided a region for the reaction intermediate to interact with the active center containing O‐containing groups. This enhanced the synergy between biomass and plastics and raised the selectivity of aromatic hydrocarbons. It provides a reference for the application of carbon‐based materials in the co‐pyrolysis of biomass and waste plastics. © 2024 Society of Chemical Industry (SCI).

Adsorption performance and mechanism of Arsenic(III) and Arsenic(V) by using copper-manganese binary oxide

ABSTRACT Arsenic contamination threatens the safety of drinking water in many areas of the world. As(V) is less toxic and easier to remove than As(III). Hence, it is essential to oxidise As(III) to As(V). Based on the previous studies, Cu-Mn binary oxide (CMBO) (with a molar ratio of Cu/Mn = 3:1) was prepared by a two-step method. The results showed that CMBO has a large specific surface area (67.74 m2/g) and pore size (16.87 nm). Moreover, CMBO has an inconspicuous crystal structure and abundant hydroxyl groups, which are favourable for arsenic adsorption. The adsorption kinetics results indicated that As(III) was oxidised to As(V) during the adsorption process, and the adsorption rate for As(V) removal was faster than that for As(III) removal. The saturated adsorption capacities of As(III) and As(V) were calculated to be 64.17 mg/g and 84.87 mg/g via the Langmuir isotherm model, respectively. The results of the pH effect studies indicated that acidic conditions promoted the removal of both As(III) and As(V) by CMBO due to the electrostatic attraction. The spectroscopic analysis results demonstrated that Mn oxides within CMBO played a vital role in As(III) oxidation. The removal of As(III) by CMBO was attributed to the synergistic effect of As(III) oxidation by Mn oxides and As sorption by Cu oxides. Overall, CMBO is a promising sorbent with great potential for removing arsenic.

Insights into the hexamine-assisted ZnO based-MOFs formation on PET fabric for improved self-cleaning, flame retardant, and hydrophilic properties

Organo-metallic frameworks (MOFs) have attracted much attention in the last decade due to their large pore size, large surface area, selective adsorption of small molecules, and optical or magnetic responses in the presence of guest molecules. Particularly, the use of MOFs on textile products through in situ synthesis leads to special properties in a simple method. Here, the polyester fabric was first activated by alkali hydrolysis and then the ZnO-based MOFs were synthesized to obtain a fabric with multifunctional features. FESEM images and EDX elemental analysis showed the presence of MOF particles and zinc, nitrogen, and hydrogen on the polyester surface. The weight of the treated samples increased however the water spreading time decreased due to the polar groups of the MOFs creating higher hydrophilic properties. The presence of hydroxyl and amine groups on the surface of the MOFs-treated polyester was confirmed by FTIR spectroscopy. The final fabric showed photocatalytic self-cleaning, and UV protection properties. In addition, TGA, ash percentage, and burnt length results demonstrated the flame-retardant properties. The tensile strength, thickness, and stiffness of the MOFs-treated fabrics also increased. Finally, the hexamine-assisted ZnO-based MOFs on the polyester surface improve its properties and usability.