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Organic molecules are widely used as structure directing agents, mesopore generating agents or zeolite growth modifiers in the synthesis of various zeolites. However, the organic molecules used in zeolite synthesis are mostly positively charged cationic molecules, since the cationic group can balance the negative charge in the zeolite structure. Here we attempt for the first time to apply an anionic surfactant fatty alcohol polyoxyethylene ether ammonium sulfate (AESA) in the crystallization of zeolite Beta. It is found that both the crystallization process and the characteristics of the product were affected by the addition of AESA into the synthesis. Compared with that without AESA, it shows that the induction period was significantly prolonged for the synthesis of zeolite Beta with AESA, and the crystallinity and the completeness of the crystal were improved. The yield of the product was increased when AESA was used in the synthesis. The framework Si/Al ratio was increased when AESA was added into the synthesis gel, which could be due to the fact that the anionic surfactant AESA facilitated the formation of Si-O-Si bonds and hindered the combination of the negatively charged aluminum species to silicon species to form Si-O-Al bonds, thus increasing the incorporation of Si and reducing the incorporation of Al into the framework. Moreover, we demonstrate an ability to enrich chiral polymorph-A in zeolite Beta by using AESA in the crystallization, with the proportion of polymorph-A in the as synthesized zeolite Beta reaching 77.9%. It is reported that AESA did not remain in the structure of zeolite Beta when the crystallization was completed, which implies that AESA plays a role of zeolite growth modifiers during the crystallization. The results of this study suggest that anionic surfactants can be used in zeolite synthesis to optimize the crystallization process and achieve zeolites with the desired properties.

The adsorption of toluene and 1,3,5-trimethylbenzene and the catalytic transformation of 1,3,5-trimethylbenzene are applied as probing approaches to characterize the pore system of hierarchical EU-1 zeolites prepared using organofunctionalized fumed silica as the silicon source. The adsorption and diffusion of toluene and 1,3,5-trimethylbenzene are significantly improved in the hierarchical EU-1 zeolites compared with the conventional microporous EU-1 zeolite. The adsorption kinetics of toluene and 1,3,5-trimethylbenzene suggested that introducing mesopores significantly increases the rate of adsorption and improved the diffusion of large molecules. In the catalytic transformation of 1,3,5-trimethylbenzene, the conversion of 1,3,5-trimethylbenzene on the hierarchical EU-1 zeolites is doubled compared with the conventional microporous EU-1 zeolite, due to the improved diffusion of bulky molecules and enhanced accessibility of active sites in the hierarchical EU-1 structure. Although isomerization is the main reaction, differences are observed in the product ratios of isomerization to disproportionation between the hierarchical EU-1 zeolites and the microporous counterpart with different times on stream. The transformation of 1,3,5-trimethylbenzene over the hierarchical EU-1 zeolites has a higher isomerization to disproportionation ratio than that over the microporous EU-1 zeolite; this is due to the increased mesoporosity.

Three 1/10-scale bridge pier specimens were tested under quasi-static test. The specimens included two precast specimens (PC1 and PC2) and one cast-in-place reference specimen. The two precast bridge pier specimens were connected with prestressing threaded steel bar and steel flange at the connection between precast pier column and the foundation, and non-socket assembly scheme and socket assembly scheme are adopted, respectively. They were tested to verify the seismic performance of prefabricated piers connected by prestressed threaded steel bars and steel flanges and study which assembly scheme is better for non-socketed and socketed piers. The results show that the prefabricated pier with the combination of the prestressed threaded steel bars and steel flange has higher cracking load and smaller residual displacement, which indicates that it has good service performance and good self-resetting ability. Compared with the non-socket assembly scheme, the socket assembly scheme is superior due to its higher ductility, higher overall initial stiffness, and higher energy dissipation capacity. Therefore, the prefabricated assembled pier with the socket connection scheme of the combination of the prestressed threaded steel bars and steel flange has good service performance and seismic performance. After that, a hysteretic model for the precast assembled columns was proposed, which has a good agreement with the test results.

Ancient masonry towers are an important cultural heritage and particularly vulnerable to damage during earthquakes. To investigate the dynamic characterization and the seismic performances of historical masonry towers, a 1/8-scale masonry model representative of an ancient Chinese tower was studied by shaking table tests. The experimental model was subjected to four scaled earthquake ground motion in two directions, the dynamic characteristics, the seismic response as well as the failure mechanism were analyzed. In addition, a nonlinear finite element model was also established with macro-modeling approach to further study its seismic response, the results between the tests and the model were compared and agreed well.

To reveal the influence of acid sites with different spatial locations of USY zeolite with different micro-/mesoporous structures and Si/Al ratio, catalytic cracking of methylcyclohexane on the zeolites is employed to study the synergism effects of acid sites and porous structures (“active region”) in the hierarchical USY zeolites. The results showed that the hierarchical USY zeolites have increased numbers of accessibly strong Brønsted acid sites and greatly enhanced diffusion ability due to the hierarchical pore-structure, resulting in mainly monomolecular protolytic scission in cracking reactions and less bimolecular hydrogen transfer. The isomerization reaction is from intramolecular transalkylation and the isomerics are the intermediates of the cracking reaction. The protolytic cracking that occurs in hierarchical high-silica USY-zeolites follows the Haag-Dessau cracking.

Porous activated carbon particles (GAC-1) with ultra-high specific surface area were prepared from starch by hydrothermal carbonization and high temperature activation. The porous structure and surface morphology of GAC-1 were characterized by N2 adsorption desorption isotherm and SEM. Compared with the commercially available activated carbon with the same particle size, the porous GAC-1 with ultra-high specific surface area shows better adsorption performance for CODCr, pyrazole and chloroform in wastewater. The results show that when the amount of activated carbon in the fixed bed is 160 g/L, the removal rate of CODCr, pyrazole and chloroform is 97.3%, 96.1% and 98.0%, respectively. The effluent meets the reuse requirements of the plant (CODCr ≤ 1500 mg/L). Finally, the activated carbon was regenerated five times by simple thermal regeneration method, and the COD removal rate could still reach 87.9%.

Mesoporous EU-1 zeolites with adjustable mesoporosity have been prepared by employing silanized silica into the starting synthesis gel, based on the hinder effect of organic moiety to crystal growth. The synthesized mesoporous EU-1 zeolites were characterized by XRD, NMR, SEM/TEM and N2 adsorption/desorption at 77 K, showing the persistence of inherent microporous framework structure of EU-1 zeolite and the existence of additional mesopores within the range of 3–10 nm. The generation of mesoporosities is from the intercrystalline voids of nanocrystal aggregates. The introduction of mesopores in EU-1 zeolite increased the adsorption of mesitylene with the kinetics diameter larger than the micropore size, and made it possible for the diffusion pattern of n-heptane from one-dimensional in microporous EU-1 to three-dimensional in mesoporous EU-1. This result together with the enhanced accessibility of acidic sites of mesoporous EU-1 improved greatly the catalytic activity and product yields of cumene cracking reaction involving bulky molecules.

The accumulation of heavy metal on catalysts during petrochemical process produces deactivated catalysts that cannot be directly disposed in nature, due to the high toxicity. The elimination of the detrimental effect of heavy metal ions can be achieved by immobilizing these ions in the form of spinel structure, yet this requires high-temperature calcination. Herein, Ni2+ ions are stabilized and confined within the surface NiAl2O4 on Al2O3 through hydrothermal process and subsequent low-temperature thermal treatment. The formation of nickel aluminum layered double hydroxide (NiAl-LDH) as intermediate favors the generation of surface aluminate spinel at the temperature as low as 450 ​°C. The formation of surface spinel is beneficial to restricting the mobility of Ni2+ ions. The growth and immobilization mechanisms of the surface spinel structure were proposed, which contributes to alternative and promising route for the low-temperature approach of the retention of the heavy metal ions mobility.

Lignin conversion processes produce carbon-rich residues [Oregui-Bengoechea et al. J. Anal. Appl. Pyrolysis 2015, 113, 713−722; Zakzeski et al. Chem. Rev. 2010, 110, 3552–3599] that can be converted into valuable materials such as magnetic activated carbons (MACs). Such lignin-derived MACs can be further used as functional substrates for hydrotreating NiMo catalysts. In this work, we studied the activity of different NiMo-MACs for the catalytic conversion of lignin in a formic acid/ethanol media (lignin-to-liquid, LtL, process). Two KOH-activated LtL hydrochars from eucalyptus (MACE) and Norwegian spruce (MACS) lignins were used as catalyst supports. In addition, the activity of the resulting NiMo-MACs, namely, C-MACE and C-MACS, was compared with a NiMo catalyst supported on a commercial activated carbon (AC). At reaction conditions of 340 °C and 6 h, the best result was obtained for the NiMo-MACS with a yield of 72.2 wt % of oil and 21.1 wt % of organic solids. At 300 °C and 10 h, both NiMo-MAC catalyst...

Hierarchical mordenite zeolite nano-rods bundles were successfully synthesized by a novel approach of using organosilane functioned fumed silica as silicon source. The organic moiety linked on the surface of fumed silica inhibits the growth of zeolite crystal into large size, leading to the nano-rods assembled bundles. The mordenite nanorods bundles exhibited significantly improved mesitylene adsorption capacity compared with the conventional mordenite. As a catalyst, the hierarchical mordenite nanorods bundles showed remarkable catalytic performance in the benzylation of mesitylene by benzyl chloride, due to the efficient diffusion rate and improved accessibility of the active sites in the hierarchical mordenite nanorods bundles.

Lignin is naturally abundant and a renewable precursor with the potential to be used in the production of both chemicals and materials. As many lignin conversion processes suffer from a significant production of solid wastes in the form of hydrochars, this study focused on transforming hydrochars into magnetic activated carbons (MAC). The hydrochars were produced via hydrothermal treatment of lignins together with formic acid. The activation of the hydrochars was performed chemically with KOH with a focus on the optimization of the MACs as adsorbents for CO2. MACs are potentially relevant to carbon capture and storage (CCS) and gas purification processes. In general, the MACs had high specific surface areas (up to 2875 m2/g), high specific pore volumes, and CO2 adsorption capacities of up to 6.0 mmol/g (1 atm, 0 °C). The textual properties of the MACs depended on the temperature of the activation. MACs activated at a temperature of 700 °C had very high ultramicropore volumes, which are relevant for potent...

Supplemental material, Supporting_information_4 for Probing the pore structure of hierarchical EU-1 zeolites by adsorption of large molecules and through catalytic reaction by Zaibin Guo, Wenming Hao, Jinghong Ma and Ruifeng Li in Journal of Chemical Research

CO is a toxic gas discharged as a byproduct in tail gases from different industrial flue gases, which needs to be taken care of urgently. In this study, a CuCl/AC adsorbent was made by a facile route of physically mixing CuCl2 and Cu(HCOO)2 powder with activated carbon (AC), followed by heating at 533 K under vacuum. The samples were characterized by X-ray powder diffraction (XRD), inductively coupled plasma optical emission spectrometry (ICP-OES), N2 adsorption/desorption, and scanning electron microscopy (SEM). It was shown that Cu(II) can be completely reduced to Cu(I), and the monolayer dispersion threshold of CuCl on AC support is 4 mmol&middot, g&minus, 1 AC. The adsorption isotherms of CO, CO2, CH4, and N2 on CuCl/AC adsorbents were measured by the volumetric method, and the CO/CO2, CO/CH4, and CO/N2 selectivities of the adsorbents were predicted using ideal adsorbed solution theory (IAST). The obtained adsorbent displayed a high CO adsorption capacity, high CO/N2, CO/CH4, and CO/CO2 selectivities, excellent ad/desorption cycle performance, rapid adsorption rate, and appropriate isosteric heat of adsorption, which made it a promising adsorbent for CO separation and purification.

Concrete behavior usually degrades due to freeze-thaw cycles, fire, or both. Existing studies on the degradation behavior of concrete due to exposure to high temperatures were primarily focused on unfrozen concrete. In this paper, the degradation behavior of damaged concrete, after different freeze-thaw cycles (25, 35, 45, and 55 cycles), exposure temperatures (20°C, 300°C, 400°C, and 500°C), and cooling methods (water-cooled and air-cooled), was tested with seventy-five prism specimens. The degradation behavior of the damaged concrete, such as surface characteristics, weight loss, compressive strength, peak strains, and elastic modulus, was studied and analyzed. Results show that (i) the surface color of the concrete does not change significantly throughout the test. As the number of freeze-thaw cycles and temperatures increase, the weight loss of the concrete specimens increases gradually. (ii) After freeze-thaw cycles, the relative strengths and elastic modulus of the concrete specimens significantly degrade compared with those of the unfrozen ones at same temperatures. (c) At elevated number of freeze-thaw cycles and exposure temperatures, the peak strain of the concrete increases gradually. (d) Cooling methods have different effects on the degradation of concrete under different number of freeze-thaw cycles. Finally, a uniaxial compression constitutive model for concrete after freeze-thaw cycles and then exposure to high temperatures was established and a good agreement was observed with test results.

The hierarchical zeolite ZSM-5 was synthesized in a CH3CH2OH–H2O hydrothermal system by using hexadecyltrimethyl ammonium bromide (CTAB) as sole template at a low crystallization temperature (130 °C). The effects of ethanol and CTAB on crystallization process and morphologies of ZSM-5 products were investigated. Ethanol molecules in synthesis system were beneficial to speed up crystallization, though crystal growth in NaOH-CTAB-H2O system was more difficult. The existence of CTAB resulted in highly crystalline and pure phase hierarchical ZSM-5 microspheres assembled by nanocrystals. The traces of crystallization evolution by XRD, FT-IR, N2 adsorption/desorption, SEM/TEM, 29Si MAS NMR, 27Al MAS NMR spectra and TGA revealed that the hierarchical ZSM-5 microspheres were formed through the transformation of mesostructured amorphous aluminosilicates, in which the initial surfactant micelles were gradually excluded and thus acted as a molecule structure-directing agent to direct the crystallization of MFI nanozeolite. At the same time, the CTAB may disrupt nanocrystals further growth and aggregate them into hierarchical microsphere through CTA+. Pyridine (Py) and pivalonitrile (Pn) adsorbed FT-IR spectra showed that the hierarchical ZSM-5 microspheres possessed large number of accessible acid sites due to the introduction of mesopores into zeolite. Therefore, it displayed much higher catalytic activities for both large molecules 1,3,5-trimethylbenzene (TMB) transformation and 1,3,5-triisopropylbenzene (TIPB) cracking reactions than conventional MFI zeolite, and the high selectivity to isomerization products (1,2,3- and 1,2,4-TMB) and benzene product from over-cracking.

Strong and dense activated carbon discs (ACDs) were synthesized and studied. The discs were produced in a multistep manner from a precursor based on hydrothermally treated beer waste (HTC-BW). The ...

The Mg 2 + and Ca 2 + exchange properties in the meso-zeolite LTA were investigated. These meso-zeolite materials with intracrystalline mesopores ca. 3 nm were prepared using organic functioned fumed silica as silica source. The Dual-site Langmuir (D-L) expression appropriately describes the equilibrium data for the Ca 2 + and Mg 2 + exchange. The fitting results with D-L model suggest that two kinds of ion-exchange sites in the meso-zeolites exist, one in the part of intrinsic micropore structure (internal surface area) and the other one in the part of established mesopore structure (external surface area). The latter site has lower enthalpy values of Ca 2 + or Mg 2 + exchanges than the former one. Ca 2 + or Mg 2 + exchange kinetics is conducted at 273 K, 288 K and 308 K. The results show the emergence of mesopores lowering the activation energy of ion exchange and accelerating Mg 2 + exchange extremely in the materials. The diffusion rate of hydrated Mg 2 + in the meso-zeolite LTA increases by 17.5 times, higher than that of conventional LTA at 273 K. And the meso-zeolite LTA possesses large Mg 2 + competitive ability in a solution containing Ca 2 + and Mg 2 + . These properties make the meso-zeolite LTA a suitable material which could be used effectively in hard water softening and detergent building for Mg 2 + removing.

Activated carbons were produced by chemical activation of hydrothermally carbonized (HTC) beer waste, withphosphoric acid as the activation agent. The activation was optimized within a full factori ...

Cu(I) adsorbents have high adsorption capacity and high selectivity for CO, thanks to the strong π-complexation bonds formed between CO and Cu(I) ions. It is important that the porous support for making Cu(I) adsorbents should have high surface area, however, the effect of pore size has never been reported. In the current study, Cu(I) adsorbents were prepared by impregnating activated carbons (ACs) with Cu(II) chloride and Cu(II) carboxylate, followed by heat treatment at mild condition in vacuum to get highly dispersed CuCl/AC adsorbents. Four ACs with different pore size distribution were studied as the supports for making CuCl/AC adsorbents. The pore size distribution characterized by Ar adsorption at 87 K was defined as ultramicropore (

A high-acidity HUSY zeolite with mesoporous structure was prepared by alumination with a dilute aqueous NaAlO2 solution and characterized by XRD, N2 adsorption, IR framework vibration and 29Si MAS NMR methods. The results indicated the extra-framework aluminum was reinserted into the tetrahedral framework through isomorphic substitution of framework Si (0Al) sites by Al ions, whereas the crystal and micropore structure were unaltered. FTIR spectra of hydroxyl vibrations and pyridine adsorbed on realuminated zeolites showed that the number of Bronsted acid sites and strong Lewis acid sites increased whereas weak Lewis acid sites decreased twice. The mesoporous structure composed of inter-and intra-crystalline pores in the aluminated HUSY increased the external surface area of the zeolite, improving accessibility of molecules to the active sites and enhancing its catalytic ability. The realuminated HUSY zeolite supported with Ru catalyst exhibited a higher catalytic activity for benzene hydrogenation than the parent HUSY zeolite; the reaction rate in comparison to the mesozeolite increased by 5.5 times.

An ordered mesoporous zeolite LTA is prepared by using organofunctionalized silica as Si-source. The mesoporous zeolite LTA has nano-cages of 3 nm interconnected to each other through 0.8–1.2 nm channels. A Jacobsen salen complex can be encapsulated successfully in the supercages of the zeolite. 29Si, 27Al-MAS NMR and in situFT-IR spectra reveal a new crystallization mechanism. The mesostructure and nano-supercages in the zeolite result from the bond-blocking action during the crystal growth. The zeolite has connatural micropore and ordered mesopore systems within the zeolite particles. The mesoporosity of the mesoporous zeolite can be rationally controlled by the degree of silanizing. The diffusion rate of hydrated Mg2+ in the synthesized submesoporous zeolite is 170 times higher than in a traditional zeolite at 308 K.

Activated carbons (ACs) are actively researched as electrode materials for supercapacitors and there is a significant interest to produce ACs from sustainable and low cost precursors. In this study, various ACs were prepared from hydrothermally carbonized sugars by KOH activation. Both the hydrothermal carbonization and activation processes were optimized to tailor the properties (e.g. textural properties, chemical composition, N-doping, electrical conductivity) of the ACs. For instance, the Brunauer-Emmett-Teller (BET) surface areas (S-BET) were tuned in the range of 800-3000 m(2) g(-1) with associated variation in the extent of microporosity and pore size distributions (PSDs). The ACs were evaluated electrochemically as materials for supercapacitor electrodes in a symmetrical two-electrode cell using an aqueous electrolyte. The relationship between the electrochemical, textural, electrical, and physicochemical properties were analyzed systematically to understand the key factors determining the electrochemical performance. A high specific capacitance (C-m) of similar to 260 F g(-1) was achieved at a moderately high S-BET of similar to 1300 m(2) g(-1), which was equivalent to a C-m/S-BET of 20 mu F cm(-2), for an optimal AC prepared from hydrothermally carbonized glucose. The very high surface-specific capacitance highlights that the specific surface area is certainly not the sole limiting parameter for effective electrode materials.

Two new oxohalides Co4Se3O9Cl2 and Co3Se4O10Cl2 have been synthesized by solid state reactions. They crystallize in the orthorhombic space group Pnma and the monoclinic space group C2/m respectively. The crystal structure of the two compounds are made up of similar building blocks; Co4Se3O9Cl2 is made up of [CoO4Cl2], [CoO5Cl] and [SeO3] polyhedra and Co3Se4O10Cl2 is made up of [CoO4Cl2] and [SeO3] polyhedra. As several Co-containing compounds have proved to be good catalysts for water oxidation, the activities of the two new compounds were compared with the previously found oxohalide Co5Se4O12Cl2 in reference to CoO and CoCl2. The one electron oxidant Ru(bpy)3(3+) was used as oxidizing species in a phosphate buffer and it was found that the activities of the oxohalide species were in between CoO and CoCl2. The roles of Cl(-) and PO4(3-) ions are discussed.

Particles of iron oxide (Fe3O4 ; 20–40 nm) were embedded within activated carbons during the activation of hydrothermally carbonized (HTC) biomasses in a flow of CO2. Four different HTC biomass samples (horse manure, grass cuttings, beer production waste, and biosludge) were used as precursors for the activated carbons. Nanoparticles of iron oxide formed from iron catalyst included in the HTC biomasses. After systematic optimization, the activated carbons had specific surface areas of about 800 m2g1. The pore size distributions of the activated carbons depended strongly on the degree of carbonization of the precursors. Activated carbons prepared from highly carbonized precursors had mainly micropores, whereas those prepared from less carbonized precursors contained mainly mesopores. Given the strong magnetism of the activated carbon–nano-Fe3O4 composites, they could be particularly useful for water purification.

Self-aggregated colloids can be used for the preparation of materials, and we studied long rod-like aggregates formed on the evaporation of water from dispersed particles of colloidal hydrochar. The monodispersed hydrochar particles (100–200 nm) were synthesized by the hydrothermal carbonization of glucose and purified through dialysis. During the synthesis they formed colloidal dispersions which were electrostatically stable at intermediate to high pH and at low ion strengths. On the evaporation of water, macroscopically large rods formed from the dispersions at intermediate pH conditions. The rods formed at the solid-water interface orthogonally oriented with respect to the drying direction. Pyrolysis rendered the rods highly porous without qualitatively affecting their shape. A Cu-Si alloy was reactively infiltrated into the in-situ pyrolyzed hydrochars and composites of tricopper silicide (Cu3Si)-silicon carbide (SiC)/carbon formed. During this process, the Si atoms reacted with the C atoms, which in turned caused the alloy to wet and further react with the carbon. The shape of the underlying carbon template was maintained during the reactions, and the formed composite preparation was subsequently calcined into a Cu3Si-SiC-based replica of the rod-like assemblies of carbon-based colloidal particles. Transmission and scanning electron microscopy, and X-ray diffraction were used to study the shape, composition, and structure of the formed solids. Further studies of materials prepared with reactive infiltration of alloys into self-aggregated and carbon-based solids can be justified from a perspective of colloidal science, as well as the explorative use of hydrochar prepared from real biomass, exploration of the compositional space in relation to the reactive infiltration, and applications of the materials in catalysis. &nbsp