Mesopore Surface Area Research Articles

RAFT Polymerisation and Hypercrosslinking Improve Crosslink Homogeneity and Surface Area of Styrene Based PolyHIPEs.

The influence of a polymerisation mechanism (reversible addition-fragmentation chain transfer; RAFT vs. free radical polymerisation; FRP) on the porous structure of highly porous poly(styrene-co-divinylbenzene) polymers was investigated. The highly porous polymers were synthesised via high internal phase emulsion templating (polymerizing the continuous phase of a high internal phase emulsion), utilising either FRP or RAFT processes. Furthermore, residual vinyl groups in the polymer chains were used for the subsequent crosslinking (hypercrosslinking) applying di-tert-butyl peroxide as the source of radicals. A significant difference in the specific surface area of polymers prepared by FRP (between 20 and 35 m2/g) and samples prepared by RAFT polymerisation (between 60 and 150 m2/g) was found. Based on the results from gas adsorption and solid state NMR, it could be concluded that the RAFT polymerisation affects the homogeneous distribution of the crosslinks in the highly crosslinked styrene-co-divinylbenzene polymer network. During the initial crosslinking, RAFT polymerisation leads to the increase in mesopores with diameters between 2 and 20 nm, resulting in good accessibility of polymer chains during the hypercrosslinking reaction, which is reflected in increased microporosity. The fraction of micropores created during the hypercrosslinking of polymers prepared via RAFT is around 10% of the total pore volume, which is up to 10 times more than for polymers prepared by FRP. Specific surface area, mesopore surface area, and total pore volume after hypercrosslinking reach almost the same values, regardless of the initial crosslinking. The degree of hypercrosslinking was confirmed by determination of the remaining double bonds by solid-state NMR analysis.

Enhanced adsorption and non-linear optical properties of DNA-CTAB functionalized mesoporous silica nanoparticles and their influence on enhancement of photoluminescence of Rhodamine 6G dye

We report a novel template method for synthesizing silica nanoparticles that are mesoporous as well as biocompatible. The mesoporous silica nanoparticles were synthesized using the Stober process and peptization method. We have used surface-modified deoxyribonucleic acid (DNA) with cetyl trimethyl ammonium bromide as a capping agent. The obtained silica particles were analyzed using x-ray diffraction, UV–vis spectroscopy, the Brunauer–Emmet–Teller method, scanning electron microscopy, and the open aperture Z-scan technique. The characterization results indicated that the DNA polymer’s presence influenced the formation of the silica particles. The silica particles are mesoporous, nanosized, and good adsorbent and also show enhanced non-linear optical properties when compared with existing silica nanoparticles. The solubility of the silica nanoparticles was also verified in dimethyl sulfoxide (DMSO). We have verified that the enhanced mesoporous surface area and reduced porous size of the silica nanoparticles influenced the photoluminescence of Rhodamine 6G dye in DMSO. This can be applied to lower the lasing threshold of the gain medium in lasing applications. Hence, the obtained silica nanoparticles have a variety of applications such that they can be used as adsorbents of nanosized particles, which is applicable for drug delivery purposes, bioimaging, catalytic activities, doping surface for thin film making, biosensing applications, and improvement of material quality for solar devices. The non-linear optical property of the mesoporous silica nanoparticles can be used for optical limiting applications in photonic devices.

Applicability of Consistency Criteria To Calculate the Brunauer–Emmett–Teller Surface Area of Graphite and Kerogen Mesopores

Applicability of Consistency Criteria To Calculate the Brunauer–Emmett–Teller Surface Area of Graphite and Kerogen Mesopores

Insight into the origin of oxidation behaviors of carbon fiber reinforced carbon aerogel composites with different porous skeletons

Carbon fiber reinforced carbon aerogel (C/CA) composites are promising lightweight insulators for the thermal protection of aerospace vehicles at ultra-high temperatures. However, it is seriously lack of understanding their oxidation behaviors despite its importance for the applications in oxygen-containing environments. Herein, we fabricate two kinds of C/CA using resorcinol-formaldehyde (RF) and phenolic resin (PR) as precursors and investigate the effects of original and heat-treated skeletons on their oxidation behaviors. The results show that the composites derived from RF have the lower mass losses at 600−800 °C after 35-min oxidation with an apparent activation energy of 50.80 kJ mol−1 than the counterparts derived from PR with the value of 40.14 kJ mol−1. It can be explained by the existence of more impurities and macropores as well as the larger residual tensile stress in C/CA from PR. The temperature-dependent oxidation morphology evolution is similar to the time-dependent evolution, changing from the gradually enlarged pores, to the formed grooves and even island-like structure. However, the composites from RF have reversely the higher mass losses when they were heat treated at 1600 and 2300 °C, which is attributed to its relatively lower crystallinity and larger mesopore surface area. The significant increase in crystallinity and decrease in impurities and specific surface area are the main explanations for the remarkably lower oxidation rates after heat treatment. The oxidation behaviors of C/CA are jointly governed by the carbon-oxygen reaction and diffusion within pores; and the residual stress exerts a role to different extent.

Liquid-phase benzylation of toluene by benzyl alcohol over micro-mesoporous hierarchical mordenite zeolite.

In this work, post-synthetic effective acid (HNO3) and base (NaOH) etching technique are used to create hierarchical mordenite having different pore structure. The powder X-ray diffraction (P-XRD) technique was used to confirm the crystalline structure of the base-modified and acid-modified mordenite. Field emission-scanning electron microscope (FE-SEM) was employed to confirm the structural morphology of the materials. The modified mordenite was further characterised by inductive coupled plasma-optical emission spectrometry (ICP-OES), N2 adsorption-desorption isotherms, thermogravimetric analysis (TGA), and acid-base titration, to confirm the structural integrity, presence of active acidic sites, and other vital parameters. The structure was well conserved after the change, as evidenced by the characterisation. The toluene benzylation with benzyl alcohol using hierarchical mordenite and H-mordenite produced mono-benzylated toluene. Comparison between acid treated, base treated, and H-mordenite was done. All samples were catalytically active as proved by the catalytic result in the benzylation reaction. The results show that the base alteration dramatically enhances the mesoporous surface area of H-mordenite. Furthermore, the acid-treated mordenite had the highest benzyl alcohol conversion (75%), but the base-modified mordenite had benzyl alcohol conversion of 73% with the highest mono-benzylated toluene selectivity (61%). The process was further optimised by varying the reaction temperature, duration, and catalyst quantity. Gas chromatography (GC) was used to evaluate the reaction products and gas chromatography-mass spectrometry (GC-MS) was used to confirm them. Introduction of mesoporosity in the microporous mordenite was found to have significant effect on their catalytic activity.

Enhancement of catalytic and anti-carbon deposition performance of SAPO-34/ZSM-5/quartz films in MTA reaction by Si/Al ratio regulation

In order to further improve the catalytic performance of zeolite catalyst for methanol to aromatics (MTA) technology, the double-tier SAPO-34/ZSM-5/quartz composite zeolite films were successfully synthesized via hydrothermal crystallization. The Si/Al ratio of SAPO-34 film was used as the only variable to study this material. The composite zeolite material with 0.6 Si/Al ratio of SAPO-34 has the largest mesoporous specific surface area and the most suitable acid distribution. The catalytic performance for the MTA process showed that 0.6-SAPO-34/ZSM-5/quartz film has as high as 50.3% BTX selectivity and 670 min lifetime. The MTA reaction is carried out through the path we designed to effectively avoid the hydrocarbon pool circulation of ZSM-5 zeolite, so as to improve the aromatics selectivity and inhibit the occurrence of deep side reactions to a great extent. The coke deposition behavior was monitored by TG and GC-MS, it is found that with the increase of Si/Al ratio, the active intermediates changed from low-substituted methylbenzene to high-substituted methylbenzene, which led to the rapid deactivation of the catalyst. This work provides a possibility to employ the synergy effect of composite zeolite film synthesizing anti-carbon deposition catalyst in MTA reaction.

Metal organic framework supported surface modification of synthesized nickel/nickel oxide nanoparticles via controlled PEGylation for cytotoxicity profile against MCF-7 breast cancer cell lines via docking analysis

Metal organic framework, (MOFs) supported nanoparticles have proven a path for the treatment of various carcinomas to be effective against MCF-7 Breast cancer cell lines. Despite the globally widespread applications of nickel/nickel oxide nanoparticles, Ni/NiO@LAA_PEG NPs with surfactant Polyethylene glycol, (PEG) and l-Acsorbic acid, (LAA) as reducing agents in industrial, commercial, and biomedical fields, their response to human cells has not been elucidated. Hence in the reported article Ni/NiO@LAA_PEG NPs with an average size range of 75–80 nm was used to study their interaction with MCF-7 Breast cancer cell lines. So the best of our understanding this is the study related to MCF-7 Human Breast cancer cell lines to show cyto-genotoxicity of Ni/NiO@LAA_PEG NPs which seems mediated through MTT analysis with rising effect surface enhancement and indexed porosiveness for the interfacial advancement than standard drug Doxorubicin for their comparison to show their best effectivity to prepared Ni/NiO@LAA_PEG NPs.The theoretical performance was simulated using Gaussian-09@Autodock 4.2 with crystal preparation and docked with MCF-7 Human Breast cancer cell lines PDBs to show their correlation with wet method of preparation. The synthesized Ni/NiO@LAA_PEG NPs was characterized against UV/Vis spectroscopy for determination of peak pattern of 395 nm, the functional group analysis for the best binding of stretching with framed metal network of nanoparticles was to shown out their scissoring, wagging, and CH stretching, etc. at 661, 834 and 3425 cm−1respectively by FTIR analysis and an energy band gap of 2.2 eV for Ni/NiO@LAA_PEG NPs by optical studies. The mesopore range and surface area measurement was calculated with BET adsorption and BJH plot to find their coercivity and retentivity via adsorption-desorption curve for their best catalytic performance. The current interpretation of Ni 2p spectra of oxides and other compounds is based on charge transfer assignment of the main peak at 856.4 eV and broad satellite cantered at about 861 eV to the cd9 L and unscreened cd8 final state configurations.

Mass transfer simulation on remazol brilliant blue R dye adsorption by optimized teak wood Based activated carbon

The reactive dye of remazol brilliant blue R (RBBR) can be toxic to aquatic ecosystems and humans. Hence, the objectives of this study were to optimize teak wood-based activated carbon (TWAC) via response surface methodology (RSM) to adsorb RBBR and to simulate the mass transfer process using Polymath software. The optimum conditions in preparing TWAC were discovered to be 470 Watt of radiation power, 6.40 min of radiation time, and 1.48 g/g of impregnation ratio (IR), resulting in RBBR uptakes of 83.97 mg/g and TWAC’s yield of 30.60%. Isotherm study revealed that the adsorption of RBBR onto TWAC was best described by the Langmuir model with maximum monolayer adsorption capacity, Qm of 337.55 mg/g. The kinetic data were best described by the Polymath Mass Transfer (PMT) model where the rate constant, kPTM was found to increase from 4.84 to 5.22 h−1 when RBBR initial concentration increased from 25 to 300 mg/L. The PMT model predicted the adsorption surface area, am to be 940.79 m2/g, which is highly accurate with the actual mesopores surface area of 983.25 m2/g. The RBBR molecules formed an attraction force with TWAC’s surface functional groups through hydrogen bond (cyclohexane), dipole–dipole force (polysulfides and terminal/medial alkyne), and ion–dipole force (phenol and hydroxy group). Thermodynamic parameters of ΔH°, ΔS°, ΔG°, and Ea were computed to be −3.55 kJ/mol (exothermic), 0.07 kJ/mol.K, −24.37 kJ/mol (spontaneous) and 21.23 kJ/mol (physisorption), respectively.

Synthesis of mesopore-dominated porous carbon with ultra-high surface area via urea-assisted KOH activation

A mesoporous porous carbon (PC-KOH + Urea) with ultra-high specific surface area (SSA) was prepared from steam exploded poplar through urea-assisted KOH activation. The obtained PC-KOH + Urea had an ultra-high SSA of 3316 m2 g−1 and a total pore volume (VT) of 1.96 cm3 g−1, much higher than that of PC-KOH and PC-Urea, produced by KOH and urea activation alone, respectively. Meanwhile, PC-KOH + Urea possessed extremely high mesopores surface area (Smeso) (2183 m2 g−1) and mesopore volume (Vmeso) (1.46 cm3 g−1). In addition, urea can also serve as nitrogen source to dope nitrogen into PC-KOH + Urea, resulting in nitrogen content of 3.29%. To study the effects of urea on pore-forming, thermogravimetric analysis (TG) and thermogravimetric infrared technology (TG-IR) were adopted. It can be assumed that the ultra-high SSA of PC-KOH + Urea was mainly attributed to the reactions between pyrolysis products of urea and carbon. With ultra-high SSA, mesopore-dominated structure, and nitrogen doping, PC-KOH + Urea exhibited a high specific capacitance of 335.3 F g−1 at current density of 0.5 A g−1 in 6 M KOH aqueous electrolyte. In cyclic stability measurement, the capacitance retentions of PC-KOH + Urea were 99.6% after 4000 cycles. Thus, urea-assisted KOH activation was a feasible method to produce porous carbon with excellent performance.

Molten NaCl assisted pyrolysis of ZIF-8/PAN electrospun fibers to synthesis 1D cross-linked mesoporous N-rich carbon as oxygen reduction electrocatalysts

Controllable preparation of cross-linked mesoporous carbon materials on a large scale remains challenging. In the present work, a simple NaCl-assisted pyrolysis strategy is proposed here to efficiently convert closed pores into open pores in the pyrolysis products of 2-methylimidazole zinc salt nanoparticles/polyacrylonitrile (ZIF-8/PAN) electrospun fibers to prepare 1D cross-linked mesoporous N-rich carbon-based oxygen reduction reaction (ORR) electrocatalyst. The total specific surface area of micropores and mesopores was significantly increased from 162 m2/g to 1069 m2/g (mesopores: 704 m2/g). The ORR catalytic activity of open pore was superior to that of closed pore with more positive onset potential (0.96 vs. 0.85 V) and half-wave potential (0.79 vs. 0.72 V), larger limiting current density (5.23 vs. 3.62 mA cm−2) and electron transfer number (3.89 vs. 3.15). Such enhanced performance was attributed to the transformation from closed to open pores which greatly improved the mass transfer performance and the number of active sites.

Optimization and mass transfer simulation of remazol brilliant blue R dye adsorption onto meranti wood based activated carbon

Remazol brilliant blue R dye (RBBR) brings toxicity to living organisms once it enters the environment. This study utilized response surface methodology (RSM) and Polymath software for optimization and mass transfer simulation purposes, respectively. RSM revealed that the optimum preparation conditions of meranti wood-based activated carbon (MWAC) were 441 W, 5.76 min, and 1.35 g/g for radiation power, radiation time, and KOH:char impregnation ratio (IR), respectively, which translated into 86.39 mg/g of RBBR uptakes and 31.94 % of MWAC’s yield. The simulation study predicted the mass transfer rate, rm to be 112.20 to 1007.50 s−1 and the adsorption rate, k1 to be 3.96 to 4.34 h−1. The developed model predicted the adsorption surface area, am to be 790.04 m2/g and this value is highly accurate as compared to the actual mesopores surface area of 825.58 m2/g. Mechanism analysis divulged that the interaction that occurred between RBBR molecules and MWAC’s surface were hydrogen bond (methylene and alkyne), dipole–dipole force (alkyl carbonate, terminal alkyne, and methoxy), and ion–dipole force (primary amine). The isotherm and kinetic studies found that the adsorption data obeyed the Freundlich model and pseudo-first-order (PFO) model the best, respectively. The Langmuir maximum adsorption capacity, Qm was computed to be 327.33 mg/g. Thermodynamic parameters were calculated to be −4.06 kJ mol−1, 0.06 kJ mol−1 K−1, –22.69 kJ mol−1, and 16.03 kJ mol−1 for ΔH°, ΔS°, ΔG°, and Ea, respectively, which signified the adsorption process studied was exothermic, spontaneous and governed by physisorption.

Effects of Liquid CO2 Phase Transition Fracturing on Methane Adsorption of Coal

Liquid CO2 phase transition fracturing (LCPTF) is a kind of novel waterless fracturing technology for enhancing the coalbed methane (CBM) recovery. Relevant current studies are focused on exploring the transformed effect of LCPTF on the nanopore structure in coal. However, its influence on gas adsorption capacity has been rarely reported. This study addresses coal induced with LCPTF. The structure alterations of mesopores (2–50 nm) and macropores (>50 nm) and their effects on the gas adsorption capacity are evaluated with comprehensive measurements of a mercury intrusion porosimetry, low-temperature N2 adsorption, and isothermal adsorption. The results indicate that LCPTF has an enlarged effect on macropores, resulting in an increase in pore size and volume and a reduction of the pore specific surface area. The pore-enlarged-transformed effects of LCPTF cause an increase in pore size and a reduction of the pore volume and pore specific surface area of mesopores. The variations of the pore structure after LCPTF cause a reduction of the adsorption constant a and the increase in the adsorption constant b, indicating LCPTF’s reductive effect on adsorption capacity as well as its enhanced effect on desorption capacity. A novel effect evaluation method of LCPTF for improving CBM recoverability is proposed based on the variations of gas saturation and critical desorption pressure. This study examines, from the perspective of adsorption and desorption, the mechanism of LCPTF for enhancing CBM recovery, which provides theoretical guidance for LCPTF’s technical improvement and optimization of field application so as to secure a more reliable and efficient CBM recovery.

A Comparative Study on the Microstructure and Petrophysical Properties of Undeformed and Naturally Deformed Shales

Structural deformation is one of the main impacts responsible for understanding the hydrocarbon accumulation mechanism. Predicting its function in gas storage and migration in a microscopic scale is thus a significant issue in predicting reservoir quality. The purpose of this article is to make a comparative study on the microstructure and petrophysical properties of undeformed and naturally deformed shales developed in the Southeast Sichuan Basin. The results show that (1) organic pores, ranging from 10 to 200 nm, are more developed in undeformed shale, whereas carbonate solvopores, clay-hosted pores, and microfractures are dominant in deformed shale. (2) Undeformed shales have Dubinin–Radushkevich (DR) CO2 adsorbed contents ranging between 0.009 and 0.018 g, DR CO2 micropore surface areas of 3.90–15.59 m2/g, and Dubinin–Astakhov (DA) CO2 micropore volumes of 0.002 and 0.035 cc/g. Naturally deformed shales have larger DR CO2 adsorbed contents, DR CO2 micropore surface areas, and DA CO2 micropore volumes, typically in the ranges of 0.019–0.031 g, 13.15–20.97 m2/g, and 0.006–0.012 cc/g, respectively. (3) Undeformed shales have N2 adsorbed contents ranging between 1.94 and 6.03 cc/g, Brunauer–Emmett–Teller (BET) N2 mesopore and macropore surface areas of 0.55–7.35 m2/g, and Barrett–Joyner–Halenda (BJH) N2 mesopore and macropore volumes of 0.002 and 0.006 cc/g. Naturally deformed shales have larger N2 adsorbed contents, BET N2 mesopore and macropore surface areas, and BJH N2 mesopore and macropore volumes, typically in the ranges of 5.72–14.45 cc/g, 7.47–17.64 m2/g, and 0.005–0.015 cc/g, respectively. (4) All samples have a unimodal micropore size distribution with a distinct peak associated with a 1.5 nm micropore fraction and have a multimodal mesopore and macropore size distribution. Naturally deformed shales show more homogeneous pore size distribution curves with morphological consistency than undeformed shales, indicating that structural deformation can significantly influence pore structural heterogeneity. (5) Deformed shales exhibit higher porosity and permeability compared to the undeformed samples due to the open pore-fracture network associated with the inorganic pores and microfractures. Average porosity and permeability in deformed shales can be 1.8 and 15 times higher than those in the undeformed shales. We conclude that the microstructural heterogeneity from strong to weak and the changes of a relatively single organic pore-dominated pore system to complex pores and microfractures dominated the pore-fracture system within shales due to structural deformation being the key cause of the quantitatively and qualitatively studied microstructure and petrophysical property differences.

Design of Nickel Supported Hierarchical ZSM-5/USY Zeolite Bifunctional Catalysts for One-Pot Menthol Synthesis via Liquid-Phase Citral Hydrogenation.

Nickel-supported hierarchical zeolite catalysts were prepared through a desilication reassembly process under optimized conditions and applied in one-pot menthol synthesis. In this work, the hierarchical zeolite-supported metal bifunctional catalysts were prepared with the help of desilication re-assembly and wetness impregnation techniques and applied in menthol synthesis via citral hydrogenation. The prepared catalysts were characterized using PXRD, BET, FE-TEM, NH3-TPD, H2-TPR, pyridine adsorption, and ICP-OES techniques. As a result, the physicochemical and acidic properties, such as mesopore surface area, metal dispersion, acidity, catalytic activity, and strong Lewis acid sites of pure microporous ZSM-5/USY zeolites, were significantly improved. Consequently, with the occurrence of superior physicochemical and acidic properties, the Ni/HZ-0.5 M catalyst exhibited outstanding catalytic activity (100% conversion, TOF 7.12 h-1) and menthol selectivity (83%, 4 h) with uniform stability at 100 °C, 1.0 MPa hydrogen. Similarly, the cracking rate decreased with the decrease in Bronsted acid sites.

Removal of Bisphenol S from Aqueous Solution using Activated Carbon Derived from Rambutan Peel via Microwave Irradiation Technique

Bisphenol S (BPS) was introduced to replace Bisphenol A (BPA) in plastic production. Unfortunately, recent studies have shown that BPS is toxic. This study explores the conversion of rambutan peel into rambutan peel-based activated carbon (RPAC) via the economic route of single-stage microwave irradiation technique at radiation power and radiation time of 440 W and 6 min, respectively, under CO2 gasification. The resulted RPAC posed BET surface area of 402.68 m2/g, mesopores surface area of 332.98 m2/g, total pore volume of 0.23 cm3/g, and average pore diameter of 2.26 nm, which lies in the mesopores region. The surface of RPAC was filled with various functional groups such as methylene, aliphatic fluoro, phenol, nitro, and alkyl compounds. Adsorption of BPS onto RPAC achieved equilibrium faster at lower BPS initial concentration as compared to the higher ones. Isotherm study found that the Langmuir model suits this adsorption process the best with a maximum monolayer adsorption capacity of 27.89 mg/g whereas the kinetic study showed that pseudo-second order (PSO) represented the kinetic data the best. Intraparticle diffusion plots suggested that the adsorption process consisted of three regions and each region was controlled by a different type of diffusion mechanism. Boyd plot confirmed that film diffusion was responsible for the slowest step in the adsorption process whilst thermodynamic parameters disclosed that adsorption of BPS onto RPAC was spontaneous, exothermic, governed by physisorption, and the randomness of the adsorption process was found to reduce at the solid-liquid interface.

Bioethanol to Hydrogen Membrane Surface Characteristics Change Study

The problem of the gradual transformation of the modern economy towards greater production and consumption of ‘green’ energy requires a significant revision of existing technologies. One of the possible ways to develop green energy is the use of hydrogen as the most environmentally friendly fuel. Hydrogen can be obtained both by electrolysis, using solar energy, and using biorenewable raw materials, which can be used as ethanol, biogas, peat, agricultural waste. At the same time, for regions with a low level of illumination, the production of hydrogen by electrolysis of water using electricity generated by solar panels is inaccessible, and therefore the processing of biorenewable raw materials can take a leading position. Bioethanol is a large-capacity product with a proven production technology that widely uses waste from agriculture and wood processing. Ethanol can be used as a feedstock for hydrogen generation by means of catalytic pyrolysis or catalytic steam reforming. Membrane-catalytic steam reforming of ethanol with the production of hydrogen makes it possible to obtain hydrogen without the use of an additional purification step, however, the efficiency and stability of the membrane becomes the determining parameter that ensures the efficiency of the entire process. The degradation of inorganic membranes during catalytic steam reforming is closely related to the change in porosity as a result of hydrolysis of the membrane surface. In this connection, the study of the physicochemical properties of membranes during operation can make a significant contribution to the development of stable catalytic membranes for hydrogen production. The article presents the results of studying the physicochemical properties of an inorganic membrane for ethanol steam reforming by the method of low-temperature nitrogen adsorption. The Langmuir, Brunauer-Emmett-Taylor, t-plot and Barrett-Joyner-Halenda models were used to estimate the surface change. An increase in the surface area of mesopores during the operation of the membrane was determined.

Efficient copper removal using low-cost H3PO4 impregnated red-gram biochar-MnO2 nanocomposites

Copper metal removal from wastewater is an essential step to detoxify wastewater before release into human contact. To serve the same purpose, H3PO4 impregnated and KMnO4 functionalised, red-gram seed coat biochar is synthesized, for efficient and economic biosorption of aqueous copper ions. Response Surface Methodology (RSM) is employed to achieve a high optimal adsorption capacity of 493.34 mg/g, using a low adsorbent dosage of 0.6 g/L in only 90 min. Pre- and post-adsorption characterization of the adsorbent was done using XRD & XPS spectroscopy, FE-SEM, TGA and BET analysis to study its microstructure and mechanism of adsorption. A high mesoporous surface area of 207 m2/g and the negatively charged moieties on the surface help in complexation of the ions by reduced monolayer chemisorption. Cyclic regeneration of the adsorbent was studied to assess the adsorption efficiency, which retained a value as high as 70 % after 3 adsorption-desorption cycles.

Hydrothermally stable mesoporous aluminosilicates as superior FCC catalyst: From laboratory to refinery

Well-ordered aluminosilicates (MAs) were prepared by in-situ assembly of pre-crystallized units of zeolite Y precursors at a commercial scale, and applied in an industrial fluid catalytic cracking unit for the first time. Compared with incumbent equilibrium catalyst, the surface area of trial equilibrium catalysts (30% inventory ratio) increased from 110 m2 g−1 to 120 m2 g−1. Moreover, a significant increase of the mesoporous surface area of trial equilibrium catalysts (30% inventory ratio) from 33 m2 g−1 to 40 m2 g−1 (22% increase). Furthermore, the equilibrium catalyst that contain 80% LPC-65 yields significantly lower heavy oil (0.23%) and higher total liquids (0.53%) compared with LDO-70. The industrial results demonstrated excellent hydrothermal stability and superior catalytic cracking properties, showing the promising future in the industrial units.

Application of δ-MnO2 and biochar materials in an arsenic-contaminated groundwater.

Two activated biochar materials, peanut char (δ-MnO2 /A-PC) and corn char (δ-MnO2 /A-CC), were used to treat an arsenic solution containing 97.5% As(III) and 2.5% As(V). After reacting with δ-MnO2 /A-PC for 24 h, 18.8% of As(III) and 35.4% of As(V) remained in the solution, revealing that some As(III) was oxidized to As(V) and the other was removed by adsorption. However, δ-MnO2 /A-CC caused the solution to retain 15.6% of As(III) and 41.7% of As(V) under the same conditions, indicating that δ-MnO2 /A-CC had higher oxidation for arsenic species than δ-MnO2 /A-CC. Adsorption capacities for δ-MnO2 /A-PC and δ-MnO2 /A-CC to arsenic were 1.50 and 1.53 mg/g in a solution with 0.5ppm As(III), respectively. After coating with δ-MnO2 , the proportion of mesopore surface areas of δ-MnO2 /A-CC increased from 33.3% to 79.0%, but their mesopore volumes increased from 67.6% to 89.4%. Fourier-transform infrared spectroscopy and X-ray diffraction analyses demonstrated that δ-MnO2 was coated onto the surfaces of the biochars. The 600°C-ACC had a higher specific surface area, 221 m2 /g, than the δ-600°C-APC, 81.5m2 /g; δ-MnO2 /A-CC could attach more Mn (38.2%) than δ-MnO2 /A-PC (27.8%). The elemental analysis revealed that δ-MnO2 /A-PC and δ-MnO2 /A-CC had similar carbon contents of 26.2%. PRACTITIONER POINTS: The δ-MnO2 /biochar adsorbent can oxidize As(III) into As(V) in the groundwater. δ-MnO2 /biochar adsorbed large amounts of As(III) and As(V). Adsorbent that contains more δ-MnO2 has a higher oxidation capacity. The δ-MnO2 /biochar made from corn stalks could combine with more δ-MnO2 .

Effect of desilication on the catalytic activity of Fe-FER for direct, selective, partial oxidation of methane

The effect of desilication on the physic-chemical properties of ferrierite zeolite was investigated using spectroscopic and solid characterisation techniques including N2-adsorption, XRD, SEM, H2-TPR, NH3-TPD and in situ FTIR. Stability of active oxygen species formed from N2O over the Fe-FER catalysts and the catalytic activity for direct conversion of methane to value-added products at temperatures between 300 °C and 400 °C were studied.Ferrierite zeolites, pre-treated with 0.1 M, 0.2 M and 0.3 M NaOH solutions preserved the crystal structure of the ferrierite zeolite but their textural properties were significantly modified, leading to an increase in mesopore area and creating a greater concentration of terminal Si-OH groups, concomitant with increase in the amount of extra-framework Al and reduction in the number of bridging Si-OH-Al species.Batch-mode catalytic reaction studies of methane with N2O conducted in an in situ FTIR cell demonstrate that the methoxy groups formed on extraframework iron sites followed by the migration of these species to silicon defect sites, which resulted in a decline in the intensity of terminal Si-OH groups bands in the IR spectra.N2O-TPD experiments confirm that N2O is converted to N2, O2 and NO over Fe-FER catalysts at 350 °C. The decline in the desorption temperature of these products observed over Fe-FER catalysts treated with alkaline solution is consistent with a significant increase in the mesopore surface area from 28.3 m2/g to 102.4 m2/g. The peak areas of desorbed O2 and NO were estimated, and the different ratios of O2/NO observed on these catalysts appears to be related to the difference stabilities of surface oxygen species.Studies under continuous reaction conditions demonstrate that, at a similar level of methane conversion (ca. 2.8 %), Fe-FER catalysts prepared with the moderately alkaline solution (0.2 M NaOH) results the highest yield of methanol, dimethyl ether and formaldehyde. It is asserted that this enhanced selectivity is the result of the comparatively high concentrations of terminal silanol groups, Brønsted-acid sites, stability of active oxygen species and mesopore volume.