Journal of Porous Materials最新文献

Activated carbon paper is a type of porous carbon material with a highly developed pore structure and a large specific surface area. It finds extensive applications in adsorption, complexation, and catalyst support. To prepare high-performance activated carbon paper, this study investigates the changes in performance and structure of Poly(p-phenylene terephthalamide) (PPTA) paper under CO₂ activation, ZnCl₂ activation, H₃PO₄ activation, and NaOH activation conditions. The research reveals that carbon paper after CO₂ activation has a certain tensile strength (0.36 MPa), while chemically activated carbon paper lacks tensile strength. Incorporating 15% carbon fiber (CF) into PPTA paper increases the tensile stress (1.26 MPa) and tensile strain (4.18%) of the activated carbon paper. NaOH-activated carbon paper has the highest specific surface area (1321.6 m²/g), the most disordered carbon structure (I_D/I_G = 1.22), the lowest carbon yield (23.9%), and a pore rate 4.16% higher than that of CO₂-activated samples. The activated carbon paper prepared by ZnCl₂ activation has the highest content of C = N bonds, with the nitrogen content of pyridine increasing by 31.8% compared to CO₂ activation. This indicates that ZnCl₂ protects the N elements in PPTA paper during the activation process, preventing their decomposition during carbonization. The activated carbon paper prepared by H₃PO₄ activation has the lowest electrical conductivity (1.62 S/cm).

A numerical model is proposed to investigate the electrodeposition coating process of open-porous polyurethane (PU) foams with nickel. The modelling approach is based on the mixture theory, which accounts for the multi-phase nature of the system comprising the porous foam structure and the electrolyte which consists of the deposition material in form of cations. The model takes into consideration various physical and electrochemical phenomena, including different ionic transport mechanisms, i.e. diffusion, convection and migration. By solving the governing equations numerically, the coating process and the relevant variables are predicted over time. The simulation results are compared with experimental data to assess the agreement between the model and the experimental results. The findings reveal that the numerical model provides valuable insights into the electrodeposition process and facilitates a deeper understanding of the underlying mechanisms and it can be used for optimizing the coating process parameters.

A strategy was devised for the synthesis of SAPO-34, which involved a concentrated gel system-assisted two-step crystallization method. This strategy effectively controlled the size and morphology of SAPO-34. The successful synthesis of SAPO-34 crystals with micron-scale cubic morphology and nano-scale sheets were achieved using triethylamine as a low-cost template. The paper thoroughly examined the growth evolution that occurs during the crystallization process, and it delved into the factors such as gel concentration and crystallization conditions in the synthesis. Furthermore, potential theories regarding nucleation and growth mechanisms were suggested. A systematic study was conducted to examine how the morphology and acidity of SAPO-34 zeolites impact their catalytic performance. The results confirmed that the SAPO-34 with low silicon content and lamellar structure was successfully synthesized through a two-step crystallization within a gel system of H₂O/Al₂O₃ = 30, with a thickness of approximately 50–300 nm. SAPO-34 nanosheets demonstrated a substantial enhancement in catalytic performance, with a catalytic life of 370 min and an 84.1% selectivity towards light olefins.

The reduction of nitrophenols is a broadly accepted model for catalytic processes. Incorporating nanostructures into porous materials is becoming more widely acknowledged for its great importance. This strategy has attracted much interest because of its exceptional features imparted on the catalysts, offering enormous promise in accelerating the reduction of nitrophenols. In recent years, various nanostructures have been embedded to a wide range of porous materials, such as carbon, silica, metal-organic frameworks, and other inorganic materials. These porous frameworks possess unique physical and chemical characteristics, making them well-suited for catalytic applications. This thorough review begins by explaining the mechanism of nitrophenol reduction, exploring several nanostructures based on noble metals that are commonly used for catalytic reduction. Following that, a systematic description and comparison of nitrophenols catalytic reduction using various nanostructures on porous templates such as carbon-based, silica-based, zeolite-based, polymer-based, and metal-organic frameworks (MOF) were explained. In addition, this paper also examines several functional materials to enhance the catalytic reduction of nitrophenols. Herein, this write-up intends to narrow the knowledge gap on the recently synthesized catalysts and the practical requirements for removing nitrophenol. This write-up is hoped to offer valuable insights that can aid in the practical utilization of these catalysts for wastewater remediation applications.

A silica-enhanced agarose monolith adsorbent was synthesized and evaluated as a highly porous and robust adsorbent for the removal of Janus Green B (JGB) as a cationic dye from aqueous solutions. For this purpose, the molded agarose monolith adsorbent was reinforced by incorporating silica into its structure. The effects of sample volume, pH, contact time, and stirring speed on the removal efficiency of the sorbent were optimized using a response surface methodology with a central composite design. Under the optimal conditions, the monolith achieved satisfactory removal efficiencies greater than 98% for JGB. The maximum adsorption capacity of the agarose-silica adsorbent for 200 mg L^− 1 of JGB was approximately 60 mg g^− 1. Structural and morphological characterization was performed using Fourier transform infrared spectroscopy, scanning electronic microscopy and, energy-dispersive X-ray spectroscopy. The monolith exhibited excellent regenerable properties, with a removal efficiency exceeding 96% after three times of usages. Equilibrium adsorption data showed better agreement with the Freundlich isotherm model compared to Langmuir. This work demonstrated the enhanced physical stability and high porosity of the agarose-silica monoliths for the efficient removal of JGB cationic dye from real-life water and wastewater samples.

Expanded Graphite (EG) has been widely used for treating oil-polluted water. Removal of dye pigments from oily wastewater is the biggest challenge for paint industries. So, the present work focuses on treating simultaneously oil and dye-contaminated water by introducing TiO₂/EG composite. EG samples with the highest exfoliation volume have been prepared by microwave irradiation by optimizing time and tested through an oil adsorption study with different oils. TiO₂ NPs have been synthesized by the sol–gel method. A novel EG/TiO₂ composite has been synthesized by mixing TiO₂ NPs in graphite intercalation compound (precursor) and exfoliating the mixture for the optimized irradiation time. A comparative study of the effect of EG, TiO₂ NPs, and EG3/TiO₂ composite on oil and dye-polluted water has been performed in direct sunlight. Results of UV–visible spectroscopy showed that the addition of TiO₂ NPs with EG accomplished the dye degradation along with the adsorption of oil from polluted water.

Activated carbon with appreciable level of porosity and honeycomb like structure was synthesized through simple KOH activation of biochar obtained from Caladium tricolor leaves. The synthesized activated carbon was characterized for morphological and structural characteristics using various techniques. The material possesses an enhanced BET surface area (S_BET) of 1429m²/g with significant microporous texture. XPS data revealed the presence of Nitrogen as the inherent dopant in the material which enhance electrochemical and adsorption perfmance. The activated carbon has been employed as electrode material for electrical double layer type capacitance (EDLC) type supercapacitor which showed promising specific capacitance of 428 F/g at a current density of 1 A/g. Cyclic stability studies revealed a retention of capacitance of 98% for 5000 cycles. Further, adsorption studies were conducted using Furazolidone drug and the adsorption efficiency was found to be 90% following Langmuir isotherm model. Kinetic studies revealed that the adsorption follows pseudo-second order kinetics. The material also investigated for ORR activity which showed notable results which can be further improved to be employed as a metal free Oxygen reduction reaction (ORR) catalyst.

This study was performed to achieve two important scientifically challenging goals, environmental remediation of toxic heavy metals and utilization of agricultural lignocellulosic wastes. In this work, a series of mesoporous magnetic carbon (MMC) adsorbents were synthesized by carbothermic reduction at different temperatures employing date palm (Phoenix dactylifera L.) stones as the carbon source. The synthesized adsorbents were characterized by different technquies and the results confirmed the presence of zero-valent iron (ZVI) nanoparticles and other iron oxides as products of the carbothermal reduction. The nature of phases present, crystallite size and the surface properties were found to be dependent on the calcination temperature. The adsorbent MMC700 exhibited the smallest (ZVI) crystallite size 36 nm and the largest S_BET 341 m²/g. All adsorbents showed mesoporous structure with mesopore average diameter lower than 6 nm. The performance was evaluated in the removal process of toxic Cr(VI) in an aqueous medium, and the optimum conditions of the process were reported. The removal process was dependant of solution pH where best results was achieved at pH = 2. Complete removal of chromium was achieved in less than 5 min by MMC700. The results were better fitted with pseudo-second-order kinetics and followed the Freundlich model isotherm. The maximum adsorption capacity was found to be 265.25 mg/g for MMC700, suggesting its application as an efficient, low-cost, and easily separable adsorbent for the toxic Cr(VI) removal process. The prepared adsorbents exhibited superior performance in the removal process compared to other agricultural wastes or biomass - derived adsorbents reported in literature.

Nanosized ZSM-5 zeolite with high-quality is highly desired in industrial application. This paper reports an approach of rapid synthesis of this type zeolite, being realized by crystallizing gels with the Si/Al atomic ratio of 12.5–80 at 170 ℃ for 12 h under assistance of guanidinoacetic acid (GAA). As a result, the zeolite obtained from the synthesis possesses little crystal size (120–220 nm), high-quality and good monodispersity. Being associated with the superior morphology and structure, the zeolite displayed not only longer one-pass catalytic lifetime but also much higher regeneration stability in methanol-to-olefin reaction, comparing with the zeolite synthesized without GAA addition.

A multifunctional catalyst with attractive recuperation was manufactured by impregnating 4-dimethylamino pyridine (MP) with Ni supported on MCM-41 coated with CoFe₂O₄ (MCM-41/CoFe₂O₄/MP/Ni), which effectively acted as a selective catalyst for the synthesis of tetrazole and selective oxidation of sulfide with high effectiveness. The structures of the hybrid were examined by high-resolution transmission electron microscopies (TEM), field emission scanning electron microscopy (SEM), energy-dispersive X-ray spectrometer (EDS), Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction (XRD), vibrating-sample magnetometer (VSM), elemental mapping, and nitrogen adsorption−desorption isotherm. The hexagonal system of MCM-41 is well preserved after CoFe₂O₄ and 4-dimethylamino pyridine/Ni embedding. Results showed that the magnetite nanoparticles were coated with the MCM-41 silica with the formation of core–shell structured materials, and the 4-dimethylamino pyridine (MP) was successfully immobilized on the core–shell structured support. In this approach, the MCM-41/CoFe₂O₄/MP/Ni composite with spherical particles consisted of a mesoporous structure. This catalyst was recovered and reused several times without significantly decreasing efficiency and stability.