Effect Of Different Templates Research Articles

Preparation of porous biochar from heavy bio-oil for adsorption of methylene blue in wastewater

The heavy bio-oil produced from biomass pyrolysis was used as carbon source to prepare porous biochar by one-step template method for methylene blue adsorption in wastewater. The effects of different templates and mass ratios on characteristic of porous biochar were studied. The methylene blue adsorption characteristics of porous biochar were investigated, and that of activated carbon was also discussed for comparison. The result showed calcium citrate was the most suitable template agent with the highest yield and the best microstructure of biochar. The specific surface area and micropore volume first increased and then decreased with the increasing mass ratio of template to bio-oil and carbonization temperature, reaching the maximum value of 922 m2/g and 0.182 cm3/g at 800 °C when the mass ratio was 2:1. The methylene blue adsorption capacity increased along with the increase of specific surface area and pH value. The adsorption capacity of porous biochar reached the maximum value of 411 mg/g at pH of 12, which was 28% higher than that of activated carbon. The adsorption process was consistent with Langmuir isothermal adsorption model and pseudo second-order kinetic model. This paper provides a new method to prepare effective adsorbent from heavy bio-oil for methylene blue removal.

Synthesis of stacked spherical hierarchical SAPO-34 zeolite and its methanol to olefin catalytic performance

In this paper, stacked spherical hierarchical SAPO-34 zeolite was synthesized by hydrothermal crystallization with tetraethylammonium hydroxide (TEAOH) and morpholine (MOR) as composite template by adding cetyltrimethylammonium bromide (CTAB) as mesoporogen and crystal growth inhibitor. The effects of different templates and CTAB amount on SAPO-34 zeolite was investigated by XRD, SEM, NH3-TPD, and BET. The results showed that hierarchical SAPO-34 zeolite with high MTO catalytic performance was synthesized. With the increase amount of CTAB, the morphology of SAPO-34 zeolite changed from cubic to stacked spherical. Furthermore, the use of composite template could also greatly reduce the synthesis cost of SAPO-34 zeolite, which was of significance for its industrial development.

Preparation of hydrogen storage carbon materials using bio-oil heavy components as carbon-containing precursor

A new method for preparing carbon materials using bio-oil heavy components has been proposed and their hydrogen capacity at low temperature was explored. The effects of different templates and mass ratio of template to bio-oil on specific surface area, pore size distribution and yield of carbon materials were studied. The thermal decomposition pathway of calcium citrate was proposed. Carbon materials prepared by calcium citrate have larger specific surface area (1688 m2 g−1), more uniform pore size distribution and higher yield (17.76%). The specific surface area and the microporosity first increased and then decreased with increasing mass ratio of template to bio-oil, and reached the maximum value when the mass ratio was 1:1. The yield of carbon materials increased with increasing mass ratio. Hydrogen adsorption capacity (0.73–1.80 wt%) of carbon materials increased along with the increase of specific surface area and microporosity. Furthermore, the interaction between carbon and hydrogen molecules is strong, as shown by the isosteric heat of adsorption of between 6.13 and 10.56 kJ/mol. This paper provides an economical and environmental-friendly method for the preparation of hydrocarbon storage materials, and also a new idea for the utilization of bio-oil heavy components.

The Use of Different Templates for the Synthesis of Reproducible Mesoporous Titania Thin Films and Small Pore Ultrafiltration Membranes

State‐of‐the‐art commercial membranes are made with the sol–gel method. But the pore size is somewhat restricted to control in a reproducible way. Furthermore, the synthesis of uniform pores via the sol–gel method is challenging, and therefore the resulting membranes often exhibit a limited selectivity. In contrast, the template‐assisted method (evaporation‐induced self‐assembly) described herein is able to form defect‐free membranes and thin films with more narrow pore size distributions and thus sharper cutoff curves in a more reproducible way. Moreover, the effect of different templates (Brij 58, Brij 56, Brij 78, Brij 76) and concentrations on the porosity of the titania top layer and separation performance is thoroughly investigated. The pore formation mechanism of the template‐assisted method is discussed. Under the synthesis conditions described herein, the Brij templates act as a separator, whereby the final pore size can be easily controlled by adjusting the amount of template used. Furthermore, the pores obtained with this template‐assisted method are more uniform. Such defect‐free, reproducible small pore ultrafiltration membranes with controllable pore size and narrow pore size distribution can open the path to further process intensification and more sustainable production by separating molecules with a small difference in molecular weight.

Templating Effects in the Dynamic Chemistry of Cucurbiturils and Hemicucurbiturils

AbstractThis review concentrates on the remarkable macrocyclisation chemistry of cucurbituril family members. During a single step in the condensation reaction of cucurbit[6]uril or hemicucurbit[12]uril 24 new C−N bonds are formed. In the case of hemicucurbit[12]uril this leads to the highly efficient formation of a covalently bound chain of 48 atoms. This phenomenon is possible because all cucurbiturils are built up of dynamic covalent acylaminal linkers. Moreover, the reversibility of acylaminal linkages makes the formation of macrocycles susceptible to external stimuli. Influence of the chain‐growth and chain‐cycle equilibrium and the effect of different templates in CB chemistry is discussed. As anions have a pronounced effect on formation of hemicucurbiturils, a comprehensive overview on their role in modifying the solid‐state structures of hemicucurbiturils is given.

Synthesis of PDMS-SiO2 hybrids using different templates

Xerogels’ formation in the hydrolysis and condensation reaction of tetraethyl orthosilicate (TEOS) was studied by varying pH through adopting three different type basic catalysts (n-octylamine, dodecylamine and tetradecylamine), respectively. The effect of different templates to the formation of xerogels was investigated and characterized by FTIR, N2 physisorption, TG-DSC and SEM analysis. The results showed that the morphology and textural characteristics of the xerogels prepared in three kinds of organic amine solutions were quite different. The texture of xerogels became more compact after addition of hydroxyl-terminated polydimethylsiloxane (PDMS-OH). Comparing with dodecylamine and tetradecylamine, n-octylamine is more suitable as catalyst to TEOS/PDMS for stone consolidation.

Effect of Different Templates on Electrical Properties of Textured KNN-Based Ceramics

Platelike and perovskite structure NaNbO3 (NN) with orthorhombic, SrTiO3 (ST) with cubic and BaTiO3 (BT) with tetragonal were used as templates to fabricate grain-oriented 0.94(K0.5Na0.5)NbO3-0.06LiSbO3 (0.94KNN-0.06LS) ceramics by templated grain growth (TGG). The effects of different templates on the grain orientation, ferroelectric, dielectric, piezoelectric properties and strain behavior of 0.94KNN-0.06LS ceramics were systematically investigated. Textured ceramics with high orientation factor were obtained successfully when the platelike NN was used as a template, while high degree of grain orientation cannot be obtained with ST and BT template. The templated growth of <00l> oriented grains on the NN template resulted in textured ceramics with brick significantly high <00l> texture degree corresponding to 87% Lotgering factor at 5 mol% NN templates. Textured ceramics with NN templates exhibited excellent piezoelectric properties as compared to the random counterparts due to high degree of grain orientation, while ceramics used ST templates shown excellent strain behavior.

Synthesis and Characterization of HZSM-5 Catalyst for Methanol to Propylene (MTP) Reaction

The effects of different templates on HZSM-5 catalyst morphology and activity in the conversion of methanol to propylene (MTP) were investigated. High silica HZSM-5 catalysts (Si/Al = 200) were synthesized successfully using Ludox as silica source and different structure directing agents (SDAs). XRD, SEM, FT-IR, NH3-TPD, and N2 adsorption–desorption analytical techniques characterized the catalysts. Morpholine shaped nano plate–like morphology. TPAOH as template resulted in the high BET surface area (369.4 m2/g) and crystallinity. The HZSM-5 catalysts showed significant catalytic activity. The catalyst with TPABr as template represented the highest propylene selectivity (45%), methanol conversion (99.8%), and long lifetime (72 h).

Effect of different templates and texture on structure evolution and strain behavior of -textured lead-free piezoelectric BNT-based ceramics

In this work, <001> oriented 0.90(Bi0.5Na0.5)TiO3–0.05KNbO3–0.05SrTiO3 (BNT–KN–ST) ceramics with high degree of texturing were produced by templated grain growth using different perovskite plate-like (Bi0.5Na0.5)TiO3 and SrTiO3 as template particles. The effects of different template particles on the grain orientation, structure evolution, phase stability and strain response was systematically investigated to develop the lead-free piezoelectric materials with an excellent actuating performance. The strain response increased monotonously with the increase in the degree of texturing and the optimized microstructure was found to provide excellent strain properties with a large strain of 0.38% and normalized strain Smax/Emax = 540 pm/V for the textured samples with BNT template particles at room temperature as compared to the random counterparts. The temperature-dependent strain response is also compared to randomly oriented ceramics and the results demonstrated that the textured piezoceramics with BNT template particles exhibited the enhancement in the temperature stability over the temperature range room temperature-120 °C.

Effect of different templates on structure evolution and large strain response under a low electric field in -textured lead-free BNT-based piezoelectric ceramics

<00l>-textured 0.83Na0.5Bi0.5TiO3–0.17Bi0.5K0.5TiO3 (BNT–BKT) ceramics with high degree of texturing (>80%) were synthesized by templated grain growth using different perovskite plate-like BaTiO3, SrTiO3 and NaNbO3 as template particles to develop lead-free piezoelectric materials with an excellent actuating performance. The effects of different template particles addition to BNT–BKT ceramics on the grain orientation, structure evolution, phase stability and macroscopic functional properties was systematically investigated. BaTiO3 template particles addition to form <00l>-textured BNT–BKT–BT textured ceramics suppresses an electric-field-induced long-range ferroelectric order, giving rise to a high field-induced Smax/Emax of 710pm/V under a relatively low driving field of 45kV/cm compared with existing lead-free Bi-perovskite ceramics. In particular, temperature-dependent strain response reveals that <00l>-textured BNT–BKT–5BT ceramics exhibit not only large Smax/Emax at a low driving field of 45kV/cm at room temperature but also enhanced the temperature stability of Smax/Emax featured by large Smax/Emax of 517pm/V at high temperature.

Effect of Different Templates on the Synthesis of Mesoporous Sodalite

Sodalite is a type of zeolite having ultramicropore size and high thermal stability with strong basic sites. However, sodalite has several drawbacks in the catalyst application due to its smallest pore size (2.8 Å) and low surface area. To overcome these disadvantages, microporous sodalite can be modified to have mesoporous structure but maintain its active sites suitable for catalyst applications. This study was focused on the synthesis of mesoporous sodalite using various organic templates as structure directing molecules. A hierarchical mesoporous sodalite has been synthesized hydrothermally at 150°C for crystallization by using several mesotemplate and fumed silica as a silica source. The synthesized samples were characterized using XRD, FTIR, BET surface area, and FESEM. XRD and FTIR showed that all templates being used in the synthesis produced sodalite phase. The sodalite synthesized using organosilane (trimethoxysilyl-propyldimethyloctadecyl ammonium chloride) and mixture of tetrapropyl ammonium hydroxide and cetyltrimethylammonium bromide with ratio of 1 : 1 showed mesoporosity as proven by higher BET surface area as compared to microporous sodalite with different pore structure as proven by pore distribution.

Effect of template on generating a standard curve for absolute quantification of an RNA virus by real-time reverse transcriptase-polymerase chain reaction

The effect of different templates on generating standard curves that are needed for the absolute quantification of an RNA virus by real-time reverse transcriptase-PCR (RT-PCR) was evaluated. We used infectious pancreatic necrosis virus (IPNV), a major viral pathogen of wild and cultured salmon, as a RNA virus example for the study. A dilution series of four different templates representing the IPNV protease gene (two in vitro transcribed RNAs of 100 bases and 500 bases in length, a plasmid DNA and a DNA oligo) were used as template to produce standard curves to quantify IPNV load in rainbow trout. The slope, the goodness of fit ( r 2), and the efficiency ( e) of PCR were statistically equivalent irrespective of the nature of template used in the PCR. Using a factorial ANOVA, no significant difference in IPNV copy number was observed using the four different standard curves for absolute quantification of IPNV in experimentally-challenged rainbow trout. However, when IPNV transcript abundance was less than 100 copies per reaction and when the template size was bigger than the amplicon size amplification was more variable. The data suggests that the size of the template used to generate standard curve should be very similar to the size of the amplicon. A synthetic DNA oligo template would be optimal for this purpose as it can be custom made and only requires the sequence information for its synthesis. However, if the standard curve is generated with template copy number in excess of 100 copies per reaction, the nature of the template has no effect on the standard curve, and therefore, the cheaper template would be the preferred choice of template over the other more expensive options.

Ultra-wideband pulse-based data communications for medical implants

Impulse radio (IR) ultra wideband (UWB) technology is assessed herein for wireless data communications with a capsule endoscope operating inside the digestive tract. The UWB channel is characterised for the frequency range of 1-5-GHz and line-of-sight (LOS) scenarios. Owing to the lack of a standardised mathematical model for in-body UWB signals, the channel characterisation is attained by using numerical simulations. Because of the lossy material properties of the human tissues, short delay spread of the in-body channel is observed. The design of a packet based IR-UWB transmitter is presented herein, considering the restrictions on power consumption, size, cost and complexity. A novel coherent receiver using a single-branch correlation scheme is proposed. The receiver system performance is optimised by adjusting the shape and the delay of the template pulse for providing maximum output of the correlator. Its bit-error-rate (BER) performance using bi-phase pulse amplitude modulation (BPAM) is evaluated. The effects of different templates on the system performance are also investigated. Fast synchronisation is achieved by using a bank of correlators; the number of correlator branches and the preamble length for successful synchronisation are estimated. This investigation reveals the feasibility of using IR-UWB for capsule endoscope fast data transmission.

Synthesis of cobalt–iron bimetallic nanocrystals supported on mesoporous silica using different templates

CoFe bimetallic samples containing 25 wt% total of metal content were prepared by incipient wetness impregnation of cobalt nitrate and iron nitrate salts over hexagonal mesoporous silica (HMS). A series of HMS silicas have been prepared by a neutral assembly pathway using two types of structure director: dodecylamine (DDA) and tetradecylamine (TDA). The effect of different templates in the formation of HMS mesoporous silica and bimetallic CoFe supported samples has been investigated and characterized by N 2 physisorption, X-ray diffraction (XRD), temperature programmed reduction (TPR), hydrogen chemisorption, thermogravimetric (TGA) and differential thermal (DTA) analyses. The amount of incorporated metal was estimated by atomic absorption spectroscopy (AAS). Also, a series of supported monometallic cobalt/iron samples were synthesized and compared to bimetallic ones. The textural properties revealed a lower percentage decrease in BET area and total pore volume for the CoFe/HMS (DDA) sample. XRD results showed α-Fe 2O 3 phase formation and higher Co 3O 4/CoFe 2O 4 crystallite sizes for CoFe/HMS (TDA) sample. The latter also presented lower reduction temperatures and a slightly lower dispersion (%) compared to CoFe/HMS (DDA).

Influence of template on Si distribution of SAPO-11 and their performance for n-paraffin isomerization

SAPO-11 molecular sieves were synthesized using single agent (i.e. diethylamine (DEA), di- iso-propylamine (DIPA) and di- n-propylamine (DPA)) or a mixture of DEA and DIPA (named DEPA) as the template under hydrothermal conditions. XRD indicated that the directing effect of different templates for AEL structure decreased in the order of DEPA > DPA > DIPA > DEA. 29Si MAS NMR showed that although all SAPO-11 samples synthesized at same Si content, that prepared with the mixed template contained more Si (4Al) sites, whereas Si ( nAl, 4- nSi, 0 < n < 4) environments were predominant in the samples synthesized with single template. The results indicated that the mixed template led to a better Si dispersion and then increased the number of total acid sites of SAPO-11. In the isomerization of n-tetradecane over different Pt/SAPO-11 catalysts, the sample prepared with DEPA showed high catalytic activity and selectivity for i-C 14, which were related to the most abundant weak acid sites of the sample.

Effect of different templates on microstructure of textured Na 0.5Bi 0.5TiO 3–BaTiO 3 ceramics with RTGG method

One-dimensional needle-like KSr 2Nb 5O 15 (KSN) and two-dimensional plate-like Bi 2.5Na 3.5Nb 5O 18 (BNN) particles were used as templates to fabricate grain-oriented Na 0.5Bi 0.5TiO 3–BaTiO 3 (NBTBT) ceramics by reactive-templated grain growth. The effects of the template concentration on the microstructure and orientation of NBTBT ceramics were investigated, and the mechanism of grain growth was discussed. The results show that NBTBT textured ceramics cannot be obtained with KSN template, since the needle-like KSN particles were aligned randomly along the tape casting direction. Ceramics contain perovskite NBTBT and tungsten–bronze-type KSN phase. Some cucurbit-like KSN grains resulted from the defects of needle-like KSN templates were detected. Textured ceramics with orientation factor more than 60% were obtained successfully when the plate-like BNN was used as templates. The results show that the texture fraction of NBTBT textured ceramics increase with increasing the content of BNN. The textured ceramics exhibited { h 0 0} preferred orientation have brick wall microstructure with strip-like grains aligning in the same plane as the casting plane. The reaction and crystal formation of textured NBTBT ceramics with plate-like BNN templates are by diffusion–recrystallization process. Finally the selecting rules of suitable templates are proposed.

Synthesis, characterization and catalytic properties of low cost titanium silicalite

The synthesis of titanium silicalite by two methods (gas–solid isomorphous substitution of Ti 4+ for Si 4+ and hydrothermal crystallization synthesis), aiming at decreasing its cost, and the characterization of the prepared catalyst are presented. In the hydrothermal crystallization synthesis method of titanium silicalite-1 (TS-1), TPABr can be used to replace TPAOH and the amount of TPABr can be decreased to 0.05 (TPA +/SiO 2). Organic amine cannot act as a template in the presence of TPA +. It can only regulate the basicity of the gel. The order of the template effect of different templates is as follows: TPA +>TBA +>TEA +≫organic amine. In the preparation of titanium-containing zeolite by secondary synthesis, the nature of the precursor and the preparation conditions have great influence on the incorporation of titanium into the framework. The mechanism of gas–solid isomorphous substitution is proposed, and under its guidance, we have successfully prepared Ti-ZSM-5, Ti-ZSM-11, Ti-β, and Ti-mordenite. The synthesized titanium-containing zeolites have been evaluated through catalytic hydroxylation of phenol, oxidation of styrene and epoxidation of propylene with aqueous H 2O 2. Results show that the Ti-containing zeolites possess high activity both in hydroxylation, styrene oxidation and in epoxidation.