Narrow Pore Size Distribution Research Articles

Ag–CeO2/SBA-15 composite prepared from Pluronic P123@SBA-15 hybrid as catalyst for room-temperature reduction of 4-nitrophenol

The catalytic activity of the SBA-15-supported silver and/or ceria catalysts in the 4‑nitrophenol reduction under mild conditions is described. The catalysts are prepared by wetness impregnation of Pluronic P123@SBA-15 hybrid applied to stabilize small Ag and CeO2 particles. The bare SBA-15 and the catalysts on the basis thereof are characterized by N2 sorption, XRD, SAXS, TEM, UV–vis DRS, and H2-TPR. The catalysts possess high surface area (594−754 m2/g) and narrow pore size distributions (5.5–7.8 nm). Silver and ceria particles are stabilized in a highly dispersed state (predominant sizes below 5 nm) in the ordered SBA-15 structure. The Ag–CeO2/SBA-15 catalyst demonstrates the presence of the developed Ag–CeO2 interface that enhances the catalytic activity in 4-nitrophenol reduction to 4‑aminophenol (k = 0.016 s−1) at room temperature and ambient pressure due to the cooperation of silver and ceria active sites.

Room-temperature swelling of block copolymers for nanoporous membranes with well-defined porosities

Selective swelling of block copolymers (BCPs) has been an efficient way to produce nanoporous materials with well-defined porosities. Currently, the cavitation of bulk BCP films by selective swelling needs to be performed at elevated temperatures (typically 50–70 °C), which is not only tedious in operation but also energy extensive. Herein, we develop the room-temperature (RT) swelling strategy to enable pore formation in BCP films with no need of heating. Simply introducing a solvent selective to the majority blocks of BCPs into the swelling bath allows the initiation of selective swelling-induced pore generation at room temperature because of plasticizing effect on BCP matrix. The swelling degrees and porosities of BCP films can be flexibly tuned by changing the compositions of the swelling bath and the swelling durations. The universality of this RT swelling strategy is also demonstrated by its applicability to both polystyrene (PS)-based BCPs and polysulfone-based BCPs with high glass transition temperatures. We prepare composite membranes with nanoporous polystyrene-block-poly (2-vinyl pyridine) (PS-b-P2VP) selective layers on top of macroporous substrates by using this RT swelling approach. Interestingly, thus-produced membranes exhibit more uniform pores with narrow pore size distributions, resulting in better selectivity. RT swelling is featured as convenient and energy-saving, and is desired in large-scale manufacturing of nanoporous BCP materials for various applications.

Interface engineering integrates fractal-tree structured nitrogen-doped graphene/carbon nanotubes for supercapacitors

To construct atomic-scale and seamless interface between various dimensional carbon nanostructures is essential for maximizing the componental attributes and benefiting the transport of masses, electrons, ions and energies involved in reactions and energies storages. Inspired by the structure of ‘Catalpa bungei’ tree which arranges its thorns regularly as nodes to bridge leaves and branches for nutrient transport, herein, NiMgAl layered double hydroxides (LDHs) are used to grow the graphene/carbon nanotubes (CNTs) host matrix, and then CO2 etching is employed to create defective sites within the matrix for anchoring the metal nanoparticles and grafting the tiny graphene oxide (GO) sheets. Based on such strategy, CNTs as the ‘branches’ can be grown over the metal nanoparticles and GO as the ‘leaves’ can be covalently bonding with the matrix with chemical vapor deposition (CVD), so that an all-in-one and omnidirectional fractal-tree structure of N-G/CNTs composite can be prepared deliberately. The results demonstrate that the N-G/CNTs composite has a high specific surface area of 190.66 m2 g−1, a narrow pore size distribution of 4–6 nm, uniform microstructural and compositional distribution, and excellent electron and ion conductivity. As a net consequence, the N-G@CNTs electrode exhibits excellent capacitor performance. In addition, three quasi-solid-state symmetrical supercapacitors assembled from the optimized N-G@CNTs composite can illuminate LED lamps. Our strategy can build solid ladder for manupulating structural units and integrating interfaces in a deliberate way to synergize the materials performance.

Electro-Fenton Regeneration of Activated Carbon Fibers for the Removal of Pharmaceutical Residues

Introduction The electro-Fenton process is based on in-situ production of the Fenton’s reagent in order to continuously generate hydroxyl radicals in the bulk solution [1]. It is also possible to promote the generation of additional powerful oxidant species by using anode material with high oxygen evolution overpotential. Therefore, such electrochemical advanced oxidation process (EAOP) is able to degrade a large range of organic pollutants [1]. However, energy efficiency of EAOPs is strongly affected by mass transport limitations during the treatment of low concentrations of pollutants such as pharmaceutical residues. In fact, a large amount of hydroxyl radicals are wasted in parasitic reactions such as hydroxyl radical dimerization. The combination of adsorption and electro-Fenton processes aims at overcoming this drawback. Adsorption on activated carbon fibers (ACFs) is used for pre-concentration of organic pollutants. Then, ACFs can be directly used as cathode during the electro-Fenton process for desorption, degradation and mineralization of organic compounds as well as for regeneration of ACFs for additional adsorption steps [2]. The possibility to easily regenerate ACFs improve the cost-effectiveness of this material, which presents more suitable characterisitcs than grain or powder activated carbon (e.g. low intra-particle diffusion limitation leading to fast adsorption kinetics, narrow pore size distribution leading to selective adsorption of micropollutants). This innovative strategy was applied for the removal of pharmaceutical residues. Scale-up from batch to continuous filtration reactor was investigated. Material and methods A first set of experiments was performed in batch reactor for both adsorption and electro-Fenton processes, by using clofibric acid and ofloxacin as model pharmaceutical residues. Design parameters (e.g. anode material: boron-doped diamond (BDD) or TiOx) and operational parameters (current density, treatment time) were optimized for improving regeneration efficiency and mineralization of pharmaceutical residues. Regeneration efficiency was assessed by comparing the adsorption capacity of regenerated ACFs and pristine ACFs. Mineralization rate of desorbed organic compounds was measured by total organic carbon analysis. Biodegradability and acute toxicity (Microtox®) of the solution was also assessed. ACFs were characterized by scanning electron microscopy, Hg porosimetry, and Raman spectroscopy. Then, the study was focused on the design, implementation and optimization of this combined process in a single continuous filtration reactor and using a real effluent. Results and discussion Batch experiments using clofibric acid as model pollutant were performed in order to better understand the influence of critical design and operational parameters. The efficiency of the process was discussed as regards to (i) desorption of organic compounds and regeneration efficiency, (ii) degradation and mineralization of organic compounds and (iii) stability of ACFs for several successive adsorption/regeneration cycles. By using BDD as anode and a current density of 21 mA cm-2, it was observed that increasing the treatment time from 3 to 6 h strongly improved the regeneration effectiveness from 45 to 75%. Further increasing the treatment time to 9 h did not show significant positive effect because of the lower availability of a portion of adsorbed compounds within the ACF porosity. Besides, dividing the current density by a factor of 2.5 (8 mA cm-2) only reduced the regeneration efficiency from 75 to 64%, indicating that low current density might be more cost-effective. Using TiOx instead of BDD anode also only reduced the regeneration efficiency from 64 to 60%. TiOx is a new promising electrode material that is much less expensive than BDD. Therefore, using TiOx anode was considered as a more cost-effective configuration. A great advantage of this process is also that >80% of organic compounds desorbed from ACF were mineralized, thus avoiding the production of a toxic effluent. Regeneration efficiency was then assessed during 10 cycles of adsorption/regeneration without significant decrease due to the protection of the ACF surface by the cathodic polarization effect. Finally, this treatment strategy was implemented in a continuous filtration reactor where both adsorption and electro-Fenton regeneration could take place sequentially. Process efficiency for treating a real effluent was assessed by comparing breakthrough curves of pristine and regenerated filters. The development of this technology is currently focused on point-of-use filters for domestic applications (about 5 liters per day) as well as on industrial wastewater treatment (pilot-scale unit able to treat 10-20 liters per hour).

Iron/manganese oxide-decorated GO-regulated highly porous polyacrylonitrile hollow fiber membrane and its excellent methylene blue-removing performance

Polyacrylonitrile (PAN) hollow fiber membrane wet-spun without any porogen usually has a wide pore size distribution, low porosity, and unstable porous structure. In this work, graphene oxide (GO) was selected as a structural optimizer to tune the porous structure of the PAN membrane. The results show that pore size and porosity increase from 156.4 nm and 37.0% to 590.8 nm and 81.4% as GO amount increases from 0 to 0.15%, which also causes a narrower pore size distribution. A simple and viable route of gradient hydrolysis, coordination, and oxidation was then adopted to decorate the PAN membrane with well-grown and well-dispersed iron/manganese oxide to achieve a functional membrane that could remove methylene blue (MB) from water stably and efficiently in the presence of H2O2. Compared with the membrane without GO, the functional membrane has a higher oxide decoration ratio, lower water contact angle, larger pores, higher porosity, and better mechanical property, and its MB solution flux is roughly two times higher than that of the membrane without GO. Additionally, the functional membrane can remove MB from the water after 30 cycles without any obvious efficiency attenuation; by contrast, MB removal efficiency induced by the membrane without GO attenuates remarkably after 25 cycles.

RESEARCH FOR FORMING POROUS STRUCTURES BASED ON PVC

In this work, we report on phase equilibrium in systems «plasticizer mix - blowing agent». Dioctiphthalate, butylbenzylphthalate and dicresyl phosphate were used as plasticizer, and simple oligoesters (ethylene glycol, diethylene glycol, triethylene glycol) served as a blowing agent. We conducted an experiment and built triple phase diagrams. Diphenylcresylphosphate proved to be fully compatible with diethylene and triethylene glycol, but not to the ethylene one. Triple systems «Butyl benzyl phthalate - Diphenylcresylphosphate - Simple oligoesters» turned out to be homogeneous for several created compounds. To achieve this for a triple system, the minimal quantity threshold is either 20% of triethylene glycol or 30% of diethylene. As for the case of dioctyl phthalate for second plasticizer, the minimal threshold for blowing agents is 70%. We constructed a device that allows to detect phase equilibrium for liquid systems. We devised several compounds and a technological proccess for creating porous PVC-based membranes using thermal molding. We selected such molding due to several advantages when compared to other methods for producing porous membranes, such as: required density, elasticity, open pores, and narrow pore size distribution. We managed to create several samples based on emulsion type PVC, butyl benzyl phthalate, diphenylcresyl phosphate, diethylene and triethylene glycol. During the phase inversion thermal process temperature should be around 180 degrees of celsium. Porous materials have the following properties: open porosity 38-44%, breaking strength 1.0 – 1.2 MРa, relative extension 43-63%, maximal pore size (2.3 – 2.8)·10-6 m, average pore size (0.5 – 1.1)·10-6 m.

Effect of oxidation degree of GO nanosheets on microstructure and performance of polysulfone-GO mixed matrix membranes

Graphene oxide with increasing degree of oxidation (GO-x) were incorporated in polysulfone (PSF) mixed-matrix ultrafiltration membranes. Synthesized GO-x were characterized for average particle size by AFM and DLS method; oxygen functionalities and nanostructure properties by XPS, FT-IR, XRD, Raman analysis, TEM, and elemental analysis; surface charge by zeta potential. Increasing oxidation degree, increased the proportion of carbonyl functional groups, exfoliation, lowered zeta potential and particle size in GO. GO-x with higher oxidation degree showed significantly improved dispersibility in N-methyl-2-pyrrolidone and polysulfone matrix. Blending hydrophilic GO-x, enhanced phase-separation kinetics improving porosity, tensile strength, permeability, protein rejection, and fouling resistance of membranes. With the increase in the oxidation degree of the matrix, contact angle and surface charge on the membranes decreased. 2%-GO-7/P membrane showed permeate flux of 352 kg m−2 h−1 bar−1 while, 1%-GO-7/P membranes acquired permanent negative charge and displayed permeability of 250 kg m−2 h−1 bar−1 with BSA rejection of about 97%, compared to control membrane permeability of 102 kg m−2 h−1 bar−1 with BSA rejection of about 91%. Thus, the membrane flux-rejection trade-off is overcome. 1%-GO-7/P membrane displayed exceptional flux recovery of over 99% on simple DI water flushing. The superior performance of GO-x/P membranes is attributed to faster diffusion rate of water across GO matrix over that through the polymer solution, which increased the number of thermodynamic instabilities giving higher rate of phase inversion resulting in narrow pore size distribution and higher pore density, demonstrating simple approach for enhancing performance of UF membranes.

Carbon Gels-Modified TiO2: Promising Materials for Photocatalysis Applications

Carbon gels are a kind of porous organic polymer, which play pivotal roles in electrode, supercapacitor, hydrogen storage, and catalysis. Carbon gels are commonly prepared by the condensation of resorcinol and formaldehyde. The as-prepared polymers are further aged and sintered at a high temperature in an inert atmosphere to form cross-linked and intertwined porous structures. Owing to its large specific area and narrow pore size distribution, this kind of material is very appropriate for mass transfer, substrate absorption, and product desorption from the pores. In recent years, carbon gels have been discovered to function as effective hybrid materials with TiO2 for photocatalytic applications. They could act as efficient deep-traps for photo-induced holes, which decreases the recombination probability of photo-induced carriers and lengthens their lifetime. In this mini-review, we will discuss the state-of-the-art paragon examples of carbon gels/TiO2 composite materials applied in photo(electro)catalysis. The major challenges and gaps of its application in this field will also be emphasized.

Mesoporous Mixed Zirconium–Niobium Oxide (Zr6Nb2O17): An Efficient Catalyst for the Phenol Red Bromination Reaction

In search for the improved catalytic efficacy, considerable attention has been focused on mixed metal oxides in the last decade. The present study reports catalytic activity of mesoporous mixed metal oxide, Zr6Nb2O17 for the first time. In this study, the mesoporous Zr6Nb2O17 has been synthesized through a soft template based wet chemical approach. The mesoporous Zr6Nb2O17 is realized after the removal of surfactant through calcination at 500°C, and preserves its mesoporosity after crystallization by heat treatment at 550°C. The synthesized oxide exhibits surface area as high as 221 m2/g and pore size of 3.3 nm with narrow pore size distribution. The synthesized mesoporous Zr6Nb2O17 shows significant catalytic activity for the bromination of phenol red. Careful structural characterizations and catalytic activity studies of the mesoporous Zr6Nb2O17 are documented in this report.

Mesoporous Octahedron-Shaped Tricobalt Tetroxide Nanoparticles for Photocatalytic Degradation of Toxic Dyes.

The present article reports a facile approach to fabrication of mesoporous octahedron-shaped tricobalt tetroxide nanoparticles (Co3O4 NPs) with a very narrow size distribution for eco-friendly remediation of toxic dyes. Co3O4 NPs were fabricated by a sol–gel process using cobalt chloride hexahydrate (CoCl2·6H2O) and monosodium succinate (C4H5O4Na) as a chelating/structure-directing agent and sodium dodecyl sulfate as a surfactant. Moreover, the phase structure, elemental composition, and thermal and morphological facets of Co3O4 NPs were investigated using XRD, FT-IR, EDS, Raman, XPS, TGA, SEM, and TEM techniques. The face-centered cubic spinel crystalline structure of the Co3O4 NPs was confirmed by XRD and SEM, and TEM analysis revealed their octahedron morphology with a smooth surface. Moreover, the narrow pore size distribution and the mesoporous nature of the Co3O4 NPs were confirmed by Brunauer–Emmett–Teller measurements. The photocatalytic activity of Co3O4 NPs for degradation of methyl red (MR), Eriochrome Black-T (EBT), bromophenol blue (BPB), and malachite green (MG) was examined under visible light irradiation, and the kinetics of the dye degradation was pseudo-zero-order with the rate constant in the order of MR > EBT > MG > BPB. Furthermore, the mechanism of photo-disintegration mechanism of the dye was examined by a scavenging test using liquid chromatography–mass chromatography, and its excellent photodegradation activities were attributed to the photogenerated holes (h+), superoxide (O2–) anions, and hydroxyl (·OH) radicals. Finally, the synergistic effect of the nano-interconnected channels with octahedron geometry, mesoporous nature, and charge transfer properties along with photogenerated charge separations leads to an enhanced Co3O4 photocatalytic activity.

New Insight into the Confinement Effect of Microporous Carbon in Li/Se Battery Chemistry: A Cathode with Enhanced Conductivity.

Embedding the fragmented selenium into the micropores of carbon host has been regarded as an effective strategy to change the Li-Se chemistry by a solid-solid mechanism, thereby enabling an excellent cycling stability in Li-Se batteries using carbonate electrolyte. However, the effect of spatial confinement by micropores in the electrochemical behavior of carbon/selenium materials remains ambiguous. A comparative study of using both microporous (MiC) and mesoporous carbons (MeC) with narrow pore size distribution as selenium hosts is herein reported. Systematic investigations reveal that the high Se utilization rate and better electrode kinetics of MiC/Se cathode than MeC/Se cathode may originate from both its improved Li+ and electronic conductivities. The small pore size (<1.35 nm) of the carbon matrices not only facilitates the formation of a compact and robust solid-electrolyte interface (SEI) with low interfacial resistance on cathode, but also alters the insulating nature of Li2 Se due to the emergence of itinerant electrons. By comparing the electrochemical behavior of MiC/Se cathode and the matching relationship between the diameter of pores and the dimension of solvent molecules in carbonate, ether, and solvate ionic liquid electrolyte, the key role of SEI film in the operation of C/Se cathode by quasi-solid-solid mechanism is also highlighted.

Supported silver catalysts prepared via melt infiltration: Synthesis, characterization and performance in selective hydrogenation

Heterogeneous supported catalysts are often synthesized by impregnation or precipitation methods. Recently, melt infiltration has emerged as an alternative method that allows high metal loadings and eliminates the need for a solvent, but challenges arise regarding control over the particle size and distribution. In this work, melt infiltration for the synthesis of supported silver catalysts is explored. The narrow pore size distribution of the chosen ordered mesoporous silica support, SBA-15, allowed in depth in-situ and ex-situ characterization of the infiltration of the precursor, molten silver nitrate, into the support and its subsequent decomposition to form metallic silver nanowires or nanoparticles. The heat treatment parameters during decomposition played a key role in determining whether nanowires or nanoparticles were formed. The supported silver catalysts containing high silver weight loadings were investigated in the selective hydrogenation of cinnamaldehyde, where the silver nanowires showed superior activity and selectivity over the nanoparticles. Hence, melt infiltration shows great promise for the synthesis of supported silver catalysts containing high silver weight loadings, which are applicable in, e.g., selective oxidation or hydrogenation reactions.

Conjugate Microporous Polymer-Derived Conductive Porous Carbon Nanoparticles with Narrow Pore-Size Distribution for Electromagnetic Interference Shielding

Conductive porous carbon nanoparticles (PCNs) with narrow pore-size distribution are considered as a versatile platform for material design and multiapplications, but their fabrication still remain...

Tensile mechanics of polymeric foam ribbons

Whereas size reduction that accompanies new technologies calls for more complex and more constrained shapes for foams to be used as seals, ribbons or surface coatings, little is known about the mechanics of foam systems characterized by a potentially small number of pores across their thickness and possessing parietal or free surface pore layers. Elastic stiffness and rupture stress have been measured for open-cell foam ribbons produced thanks to a method allowing to tune finely and independently several crucial parameters: ribbon thickness, pore size and solid volume fraction. Results reveal that the longitudinal elastic stiffness of foam ribbons increases significantly as the number of pores across the ribbon thickness decreases within the range 1–10. This increase is understood through the contribution of the parietal layers with respect to the bulk layers. Similarly, rupture stress of foam ribbons characterized by narrow pore size distributions increases as a function of the ratio pore size/ribbon thickness. All others things being equal, the rupture stress is smaller for polydisperse samples compared to monodisperse samples.

Power generation by reverse electrodialysis in a single-layer nanoporous membrane made from core-rim polycyclic aromatic hydrocarbons.

Nanoporous graphene and related atomically thin layered materials are promising candidates in reverse electrodialysis research owing to their remarkable ionic conductivity and high permselectivity. The synthesis of atomically thin nanoporous membranes with a narrow pore size distribution, however, remains challenging. Here, we report the fabrication of nanoporous carbon membranes via the thermal crosslinking of core-rim structured monomers, that is, polycyclic aromatic hydrocarbons. The mechanically robust, centimetre-sized membrane has a pore size of 3.6 ± 1.8 nm and a thickness of 2.0 ± 0.5 nm. When applied to reverse electrodialysis, the nanoporous carbon membrane offers a high short-circuit current with an output power density of 67 W m-2, which is about two orders of magnitude beyond that of the classic ion-exchange membranes and current prototype nanoporous membranes reported in the literature. Crosslinked and atomically thin porous polycyclic aromatic hydrocarbon membranes therefore represent new scaffolds that will revolutionize the rapidly developing fields of sustainable energy and membrane technology.

Achieving high volumetric EDLC carbons via hydrothermal carbonization and cyclic activation

A novel activation method involving hydrothermal carbonization (HTC) and a pressure-induced low temperature oxidation has been demonstrated for cellulose derived HTC char by using hydrogen peroxide as an active di-oxygen source. The optimized porosity versus gravimetric capacitance results from cellulose derived HTC char synthesized at 220 °C. Almost homogeneous and small particle size micro-ellipse/sphere, relatively high surface area and narrow pore size distributions lead to a high bulk density, i.e. 0.73 g cm−3, of coating-type electrodes, which is much denser than those manufactured from steam-activated carbons for supercapacitor industry, i.e. 0.52 g cm−3. The resulting carbon prepared herein achieves a relatively high volumetric capacitance in an organic electrolyte-based supercapacitor, reaching a competitive value of an industrial system with the features being environment-friendly, cost-effective as well as high yield, and less energy consumption.

Porous Carbons Derived from Sustainable Biomass via a Facile One-Step Synthesis Strategy as Efficient CO2 Adsorbents

In this work, porous carbons were achieved from sustainable biomass lotus stalk. Unlike the common carbonization-activation two-step method, a facile one-step KOH activation procedure was explored to make the carbonaceous sorbents. The as-made adsorbents have advanced porous structures and hold superior CO2 uptake, up to 3.68 and 5.11 mmol/g at 1 bar, 25 and 0 °C, respectively. After carefully checking the relationship of CO2 uptake with each porous characteristic, the volume of narrow micropores is found to be the leading factor that determines the CO2 adsorption abilities of the adsorbents under ambient conditions. Moreover, the narrower pore size distribution is also preferential to the adsorption of CO2. Apart from the high CO2 uptake, these lotus stalk-derived adsorbents also possess extra excellent CO2 capture properties such as good recyclability, fast adsorption kinetics, reasonable CO2/N2 selectivity, suitable heat of adsorption, and high dynamic adsorption capacity. These results demonstrate that these cost-effective carbonaceous adsorbents developed by the facile one-step method have potential in the application of actual CO2 capture.

Synthesis of highly ordered TiO2-Al2O3 and catalytic performance of its supported NiMo for HDS of 4, 6-dimethyldibenzothiophene

The highly ordered mesoporous TiO2-Al2O3 composite oxides were prepared via a facile evaporation-induced self-assembly (EISA) method. All of those synthesized materials were characterized by means of XRD, XRF, N2 adsorption, FTIR, Py-FTIR and TEM. The results show that the hexagonally ordered mesoporous TiO2-Al2O3 oxides with high specific surface area, high thermal stability and narrow pore size distributions were successfully synthesized by EISA. The corresponding NiMo catalysts supported on TiO2-Al2O3 oxides were further characterized by H2-TPR, HRTEM and XPS. Their hydrodesulfurization catalytic performances were tested in a fixed-bed reactor, using 4,6-dimethyldibenzothiophene as the probe. The analyzing results exhibit that the incorporation of TiO2 could effective weaken the support-metal interactions, thus enhancing the reduction degree of active metals and forming more “Type II” Ni-Mo-S active phases that would be beneficial for the HDS of highly refractory organosulfur compound. The catalytic results reveal that the 4,6-DMDBT conversion over NiMo/TA-n catalysts gradually increased as the Ti/Al molar ratio increases, and reaches a maximum values at NiMo/TA-0.4. The NiMo/TA-0.4 exhibited the highest hydrodesulfurization catalytic performance of 4,6-DMDBT due to the synergistic effect of suitable textural properties, high thermal stability and moderate metal-support interactions.

Optimization of γ-Alumina porosity via Response Surface Methodology: The influence of engineering support on the performance of a residual oil hydrotreating catalyst

As is evident in the literature, co-precipitation process has been narrowly studied from the "process" point of view thus far, and consequently majority of this complex phenomenon remains unknown scientifically. This work firstly tries to screen in depth the synthesis procedure of γ-Alumina in terms of precipitation, whereas such key parameters governing this process as temperature, reactant concentrations, mixing rate, and aging time are thoroughly analyzed by using Response surface methodology (RSM) for the very first time. Considering some significant novel interactions between these variables, the porosity of the final materials in terms of Specific Surface Area (SSA), Total Pore Volume (TPV), and Mean Pore Diameter (MPD) could be adjusted without using any surfactant or other additional organic compounds. For instance, simultaneous enhancement in SSA, TPV, and MPD, respectively, up to 334.5 m2. g−1, 1.93 cm3.g−1, and 23.01 nm with a narrow pore size distribution were achieved only by adjusting the process variables which have not been reported ever before. Two optimized materials suggested by Central Composite Design (CCD) were reproduced, analyzed by using such techniques as XRD, FT-IR, BET, SEM, and TG analyses and then used to prepare final Hydrotreating (HDT) catalyst for application in a trickle bed continuous hydrotreater.

Sludge‐based mesoporous activated carbon: the effect of hydrothermal pretreatment on material preparation and adsorption of bisphenol A

AbstractBackgroundThe excess sludge produced by sewage treatment plants contains a large number of pollutants, which is of huge environmental risk. Transforming this kind of solid waste into adsorption materials is an effective approach to realize the resource utilization of sludge. Combined with hydrothermal pretreatment and chemical activation, the synthesis of sludge‐based mesoporous carbon is used to remove bisphenol A (BPA) in wastewater.ResultsA resource recycling measure to prepare mesoporous activated carbons (MACs) from sewage sludge was developed via the combination of hydrothermal pretreatment and chemical activation using sewage sludge and sulfuric acid as carbon precursor and activating agent, respectively. The combination of hydrothermal pretreatment and chemical activation not only can make efficient use of the activating agents but also facilitate the deep pyrolysis of the sludge. The resultant MAC obtained using the hydrothermal pretreatment possessed a larger total surface area, less crystalline phase and a narrower pore size distribution compared to other samples. Meanwhile, the MAC obtained from hydrothermal pretreatment presented the highest amount of adsorption of BPA and achieved a better capture than the reference commercial activated carbons. In addition, a possible adsorption mechanism has been proposed to further analyze the enhanced adsorption performance.ConclusionsThe yield and mesoporous content of the obtained MAC is 59.19% and 31.51%, respectively. The maximum adsorption capacity for BPA is 137.87 mg g−1. Microporosity, hydrogen bonding and π–π effect introduced by the hydrothermal pretreatment play an important role in BPA adsorption. © 2020 Society of Chemical Industry