Surface Area Of Zeolite Research Articles

Characterization of Zeolite A from Coal Fly Ash Via Fusion-Hydrothermal Synthesis Method

Zeolite A has been successfully synthesized from coal fly ash by using fusion followed by hydrothermal method. This paper describes the characterization of zeolite A. The effects of hydrothermal time, Si/Al molar ratio, and alkalinity in the converting coal fly ash to zeolite A were also investigated. The coal fly ash was obtained from a local power plant at East Java, Indonesia and contained major oxides such as SiO2 (18.60 wt%), Al2O3 (7.18 wt%), Fe2O3 (40.20 wt%), CaO (25.20 wt%). The fusion hydrothermal method consists of the following steps: pre-treatment, fusion of coal fly ash with sodium hydroxide, aging, and hydrothermal process. The synthesized material was characterized by using X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Fourier Transform Infrared (FTIR), and specific surface area analytical method. The results show that the products contain zeolite A as the major phase, while the highest specific surface area of zeolite A is 37.121 m2/g. It implies that zeolite A as a higher value added product can be obtained from a solid waste/by-product of power plant, which has wide range applications, including for ion exchange and heavy metal adsorbent from waste water.

Preparation and Characterization of mordenite Zeolite from Iraqi Sand

Mordenite zeolite have been successfully synthesized from prepared nano-silica by hydrothermal method at 25 0C for 3 days. The produced sample was studied using XRD, XRF, SEM, FT-IR, AFM and BET surface area. SEM showed that the prepared sample crystallized in needle shape crystals. BET surface area and pore size of H-mordenite zeolite were 336.7 m2/g and 2.49 nm, respectively. AFM show that the average crystal diameter was 111 nm. Si/Al ratio and ion exchange percentage measured by XRF were 7.544 and 99.62 %, respectively.

Modification of pillared MFI zeolite nanosheets by nitridation with tailored activity in benzylation of mesitylene and benzyl alcohol

Abstract The modification of pillared MFI zeolites was performed by nitridation of silica pillared MFI zeolite nanosheets under NH3 atmosphere with different time. The resultant zeolites were characterized by a complementary combination of X-ray power diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), pyridine-IR spectroscopy and N2 adsorption–desorption isotherms. The analyses showed that the nitridation didn't destroy the crystallinity and specific surface area of zeolites, and the acidity of zeolites can be tailored by tuning the time of nitridation, resulting in the different concentration ratios of Bronsted-to-Lewis (B/L) acid sites. Moreover, the nitrided zeolites exhibited high selectivity to 2-benzyl-1,3,5-trimethylbenzene than parent silica pillared MFI zeolite nanosheets in benzylation of mesitylene with benzyl alcohol. A balance between Bronsted acid sites and Lewis acid sites can inhibit the self-etherification of benzyl alcohol and enhance the selectivity of alkylated product. These experimental data implied that nitridation was an effective method to modulate the acidity of zeolites and the synergy between Bronsted acid sites and Lewis acid sites was a decisive factor to determine the selectivity.

Ion exchange of zeolite coatings for adsorption heat pump applications

Coatings of NaA and NaX zeolites with various thicknesses were grown by direct crystallization on stainless steel plates. As a next step, ion exchange was applied to obtain the Li forms of the coatings. The materials obtained were characterized by X-ray diffraction (XRD), field emission gun scanning electron microscopy (FEGSEM), inductively coupled plasma (ICP), thermal gravimetry (TG), and N2 adsorption. The stabilities of the coatings in the ion exchange process were also determined. Li+ ions were observed to be readily exchanged with Na+ ions in zeolite coatings of various thicknesses but the percentage of exchange did not attain 100%. Favorable ion exchange conditions for obtaining both zeolite LiNaA and LiNaX coatings were determined. After Li exchange, the surface area of zeolite X increased by about 56% while the water capacities of zeolites X and A were enhanced by about 15 and 14%, respectively, for the conditions investigated. The ion exchange process resulted in some detachment from the coatings, which increased with enhanced coating thickness. Significant improvement was obtained in coating stability by using plates with roughened surfaces. Zeolite coatings in Li form may improve the performances of adsorption heat pumps, provided that relatively thick coatings remain stable to a desired extent during ion exchange.

Plasma activation on natural mordenite-clinoptilolite zeolite for water vapor adsorption enhancement

Water vapor is one of the crucial impurities in biogas which have to be removed for optimal performance. Utilization of natural zeolites as water vapor adsorbents is one of the proposed solutions. However, the small specific surface area of natural zeolite needs to be improved to increase the material adsorption capacity, one of the methods being physicochemical treatment. The consequences of the increased specific surface area by physicochemical treatment are the Si/Al ratio and hydrophobicity enhancement which counterbalance the benefits of the increased specific surface area. In this work, plasma activation treatment was applied successfully to increase the water adsorption capacity of natural zeolites after dealumination. The transformations of the chemical and physical properties of the material after plasma treatment are discussed. Our results point that the certain intrinsic properties on the zeolites in terms of Si/Al ratio and specific surface area are prerequisite to benefit from plasma activation. This work offers a new perspective on improving porous silica-based materials water adsorption characteristics which could lead to improved adsorbents in the future.

Acid and alkali treatments for regulation of hydrophilicity/hydrophobicity of natural zeolite

Hydrophilicity/hydrophobicity property of zeolite has been received much attention in recent years. Regulation of hydrophilicity/hydrophobicity of zeolite using relative simply process and cheap raw materials is needed to be further investigated and solved. The aim of this study is to investigate effect of acid and alkali treatments on structure, hydrophilicity/hydrophobicity of natural zeolite. The structure of the samples was characterized using ICP, XRF, XRD, laser particle size analyzer, N2 adsorption-desorption, XPS, SEM-EDX, etc. The hydrophilicity/hydrophobicity of the samples was determined using water vapor adsorption method coupled with BET specific surface area results. The results showed that acid treatment removed 5.05–23.26 wt% of aluminum from the framework of clinoptilonite using 0.1–3 M nitric acid while alkali treatment removed 0.49–7.64 wt% of silicon from the framework of clinoptilonite using 0.05–0.8 M sodium hydroxide. Accompanied by the removal of Al and Si, the specific surface area of zeolite obviously increased and decreased, respectively. Water vapor adsorptions on the alkali and acid treated zeolites with ascending SiO2/Al2O3 ratio gradually decreased which confirmed the increase of hydrophobicity and decease of hydrophilicity for the samples. This acid/alkali treatment method appears to be a simple and effective way to regulate hydrophilicity/hydrophobicity of natural zeolite.

A fast method for determination of surface area of zeolite-based catalysts and zeolites using near infrared emission spectroscopy

A new, fast and reagent-free method for determination of the surface area of zeolite-based catalysts and zeolites using direct spectral information from near infrared emission spectroscopy and chemometrics is described.

Investigation on the potential utilization of zeolite as an internal curing agent for autogenous shrinkage mitigation and the effect of modification

This paper presents an experimental investigation on the potential utilization of one natural zeolite as an internal curing agent for mitigation of self-desiccation and the subsequent autogenous shrinkage of cement paste with low w/b ratio (0.25). Incorporation of 20% zeolite by mass leads to higher internal relative humidity (90.4%) during the first 7 d compared to that of control sample (78.1%). It is indicating that the zeolite under investigated shows partially elimination effect on the self-desiccation and the autogenous shrinkage as well based on the time-zero defined by the onset of internal relative humidity drop. To obtain improved internal curing property, attempts have been done to modify the pore structure of zeolite by acid treatment and/or thermal treatment. However, both nitric acid treatment and thermal treatment shows negative effect on the improvement of internal curing property of zeolite. Because nitric acid treatment tends to increase the BET surface area of zeolite by increasing the volume of 2–7 nm pores, and the thermal treatment tends to reduce the porosity rather than to enlarge the pore size of zeolite.

A Further Investigation of NH4+ Removal Mechanisms by Using Natural and Synthetic Zeolites in Different Concentrations and Temperatures

We investigated the ammonium removal abilities of natural and synthetic zeolites with distinct Si/Al ratios and various surface areas to study how adsorption and ion exchange processes in zeolites perform under different ammonium concentrations and different temperatures. Five zeolites—natural mordenite, chabazite, erionite, clinoptilolite, and synthetic merlinoite—were immersed in 20, 50, and 100 mg/kg ammonium solutions. The results demonstrate that zeolites under high ammonium concentrations (100 mg/kg) possess higher physical adsorption capacity (0.398–0.468 meq/g), whereas those under lower ammonium concentrations (20 mg/kg) possess greater ion exchange properties (64–99%). The ion exchange ability of zeolites is extremely dependent on the cation content of the zeolites, and the cation content is affected by the Si/Al ratio. The surface area of zeolites also has a partial influence on its physical adsorption ability. When the surface area is less than 100 m2/g, the adsorption ability of zeolite increases obviously with surface area; however, adsorption ability is saturated as the surface area becomes larger than this critical value of 100 m2/g. When we placed the zeolites in 50 mg/kg ammonium concentration at different temperatures (5–50 °C), we found that the zeolites exhibited the highest ammonium removal ability at 30 °C and the potassium release was enhanced at 30–40 °C.

Synthesis and Characterization of ZSM-5 Zeolite from Dealuminated and Fragmentated Bayat-Klaten Natural Zeolite

Synthesis of ZSM-5 zeolite was conducted using natural zeolite of Bayat-Klaten by employing fragmentation method of sub-molten system through breaking zeolite framework into its monomer in alkaline condition at 250°C. Prior to fragmentation, one part of zeolite was treated with dealumination and the other one without dealumination, labeled as ZSM-5_a and ZSM-5_wa, respectively. Characterization with FTIR, XRD, and EDX showed that the fragmentation was successful, in which the structure of zeolite was damaged and the infrared bands due to AlO4 and SiO4 were appeared. The synthesis of ZSM-5 was performed hydrothermally using tetrapropylammonium hydroxide (TPAOH) as a directing agent of pore structure and addition of LUDOX (40% silica suspension in water). The XRD characterization showed the as synthesized materials had the structure of ZSM-5 zeolites with high crystallinity. Imaging with SEM showed the characteristic of hexagonal ZSM-5 crystals. The BET surface area analysis showed a typical surface area of microporous zeolite, 262 m2/g, and pore diameter of 1.496 nm; indicating that the ZSM-5 zeolite obtained was micropore size. The Si/Al ratio of ZSM-5_a and ZSM-5_wa were 18 and 21, respectively. These results indicated that Bayat-Klaten natural zeolite can be used as silica and alumina source for high crystalline ZSM-5 with medium Si/Al ratio and having good thermal stability. Thus, these materials are potential to be tested as fluid hydrocracking catalyst.

Effect of Mechanical Treatment on the Structure and Properties of Natural Zeolite

The morphology, specific surface area, structure, and phase composition of natural zeolite powder from the Tokai deposit which underwent mechanical treatment in a planetary mill was studied using the following methods: scanning electron microscopy (SEM), X-ray structural analysis, Brunauer–Emmett–Teller (BET) method, laser diffraction, and elemental analysis. The identification of natural zeolite X-ray patterns showed that the powder consisted of seven phases with different contents of minerals: smectite, quartz, cristobalite, clinoptilolite, illite, orthoclase, and calcite. Initially, the average size of the zeolite particles was 27 μm; after the treatment for 20 min, it was 5.5 μm; and after 600 min, it was 28 μm. Moreover, most of the particles lost their initial shape during the mechanical activation and acquired a spherical shape. It was shown that, during the first 60 min of mechanical treatment in the planetary mill, powder particles were ground, and the specific surface area increased to 33 m2/g. The further mechanical activation was determined by agglomeration of particles and a decrease in the specific surface area. The X-ray structural analysis showed that the studied powder consisted of four phases: hexagonal, monoclinic, orthorhombic, and tetragonal modifications. Mechanical treatment of natural zeolite led to the decrease in the coherent scattering regions and to the growth of microdistortions of the crystal lattice. It was shown that the continuous mechanical effect on zeolite led to the increase in the amount of an amorphous phase in the powder from 13 to 52%. The changes in the specific surface area determined by the BET method and calculated from the coherent scattering region (CSR) had the same character, and the phase composition determined the specific surface area of natural zeolite.

Performance of Activated Natural Zeolite/Cu as a catalyst on Degradation of Glycerol into Ethanol Assisted by Ultrasonic

The purpose of this study was to convert glycerol into ethanol using the catalyst of activated natural zeolite/Cu assisted by ultrasonic. The catalyst was characterized using X-Ray Diffraction and BET isotherm adsorption. The degradation process carried out at the temperature of 60 °C and at various time of 1, 2, and 4 hours. The product of glycerol degradation was analyzed using Gas Chromatography. The results showed that the structure of natural zeolite was a mordenite. The BET analysis showed that the surface area of natural zeolite is 99.096 m2/g greater than that of natural zeolite impregnated Cu that is 6.597 m2/g. The total pores, however, a natural zeolite is 0.026 cm3 smaller than that of natural zeolite impregnated Cu that is 0.058 cm3. The highest yield of ethanol as the product of glycerol degradation was 3.704% produced when the sonication times is 2 hours using activated natural zeolite catalyst. The activated zeolite has a prospect to be used as a degradation reaction catalyst for molecules that goes through the Bronsted Lowry acid mechanism.

Biophysiological and factorial analyses in the treatment of rural domestic wastewater using multi-soil-layering systems

Multi-soil-layering (MSL) system was developed as an attractive alternative to traditional land-based treatment techniques. Within MSL system, the environmental cleanup capability of soil is maximized, while the soil microbial communities may also change during operation. This study aimed to reveal the nature of biophysiological changes in MSL systems during operation. The species diversity in soil mixture blocks was analyzed using Illumina HiSeq sequencing of the 16S rRNA gene. The interactive effects of operating factors on species richness, community diversity and bacteria abundance correlated with COD, N and P removal were revealed through factorial analysis. The results indicated the main factors, aeration, bottom submersion and microbial amendment, had different significant effects on microbial responses. The surface area and porosity of zeolites in permeable layers decreased due to the absorption of extracellular polymeric substances. The findings were applied for the design and building of a full-size MSL system in field and satisfied removal efficiency was achieved. The results of this study can help better understand the mechanisms of pollutant reduction within MSL systems from microbial insights. It will have important implications for developing appropriate strategies for operating MSL systems with high efficiency and less risks.

Obtaining high crystalline ball milled H-Y zeolite particles with carbon nanostructures as a damping material

Abstract Nanosized zeolites have attracted interest for many applications including catalysis due to their higher surface area and hence more accessible active sites compared to the microsize zeolite particles. Ball milling is considered as a fast and an efficient technique to reduce the particle size down to nanometer range. However, it is usually accompanied by the formation of large undesired flakes and slabs with a loss of crystallinity and surface area. This study attempts to utilize carbon nanostructures (CNS) as a damping material to overcome the reported drawbacks. The idea of using CNS as a damping material is novel as this is the first study which reports the usage of CNS as damping material that prevents the zeolite micro particles from severe loss in crystallinity compared to the same process without CNS addition. Utilization of CNS gives two-fold advantages pertaining to its flexibility and superior mechanical properties and secondly the ease by which it can be removed off through oxidation after ball milling. Different parameters such as the ball milling solvent and post treatment conditions were varied and studied to observe the changes in final ball milled particle properties, such as morphology, crystallinity index, surface area and particle size distribution. Optimum ball milling and post treatment conditions registered a final zeolite surface area of 1522 m2/g compared to the initial 850 m2/g for micron sized particles. Moreover, x-ray diffraction and high resolution transmission electron microscopy (HR-TEM) images revealed highly crystalline zeolite nano particles with a crystallinity index of 38% which is more than 30% higher than previously reported study of ball milled zeolite particles without any damping material.

The influence of mechanical activation on the nanostructure of zeolite

A Hungarian natural zeolite was mechanically activated by grinding in a Netzsch MiniCer stirred media mill for various activation times from 0 to 480 min. The research goal was to produce submicron-size activated zeolite with narrow particle size distribution and to investigate the energetic aspects of grinding and material characteristics. During mechanical activation (MA) the grinding energy was measured and stress energy was calculated. Additionally, the particle size distribution of the product was characterized by a Horiba 950 LA laser particle size analyzer (LPSA). Furthermore, the BET specific surface area and adsorption capacity of the MA zeolite were measured using TriStar 3000 apparatus and methylene blue adsorption test, respectively. The structural characterization of mechanically activated zeolite was carried out using Rietveld refinement on X-ray powder diffractometry data, Fourier transform infrared spectroscopy and transmission electron microscopy (TEM-EDS). TEM images and LPSA data of MA zeolite revealed the presence of particles below 100 nm. Significant amorphization, as well as the decrease in clinoptilolite phase, was found during entire MA process, while methylene blue adsorption was maintained. Finally, the relationship between grinding operating parameter (specific grinding energy) and material characteristics (amorphous content, the crystallite size of quartz and clinoptilolite) was created.

Sustainable Synthesis of ZSM-5 Zeolite from Rice Husk Ash Without Addition of Solvents

The development of sustainable and environmentally friendly techniques for synthesizing zeolites has attracted much attention, as the use of solvents in the hydrothermal synthesis of zeolites is a major obstacle for realizing green and sustainable synthesis ways. As a solid waste, it still has a challenge for zeolites synthesis from rice husk ash by solvent-free method to increase its recovery rate and economic value. Our approach focused on reutilization of rice husk ash by converting it to ZSM-5 zeolite without employing solvents. The influence of TPABr/SiO2, Na2CO3·10H2O/SiO2 and synthesis time on ZSM-5 crystal growth and ZSM-5 zeolite properties were evaluated by various analytical methods. The results suggested that the optimal conditions of TPABr/SiO2, Na2CO3·10H2O/SiO2 and synthesis time for the ZSM-5 synthesis were 0.125, 0.3 and 72 h, respectively. Base on the optimal synthesis condition, the recovery rate of Si and Al were 98%, which were 70% compared with that of hydrothermal method. The synthesis process was solid phase conversion, Na2CO3·10H2O played key role in promoting hydrolysis and condensation of Si–O–Si and Si–O–Al bonds during synthesis process. The resultant ZSM-5 zeolite exhibited well-defined crystallinity and porosity, ZSM-5 aggregate particles possessed micro-/meso-porous structures. The BET surface area of synthetic ZSM-5 zeolite was 304 m2/g, comparable to hydrothermal synthetic ZSM-5 zeolite (320 m2/g). Overall, proposed synthetic route provides novel green alternative for the recovery of rice husk ash, further mitigating the environmental and health care concerns.

Hydrogen sulfide adsorption by zinc oxide-impregnated zeolite (synthesized from Malaysian kaolin) for biogas desulfurization

The adsorption of hydrogen sulfide (H2S) from the gas stream in a fixed-bed reactor has been investigated using zinc oxide (10–30wt% loading) impregnated on Na-A zeolite prepared from local kaolin. The adsorbents obtained were characterized by XRF, XRD, FTIR, nitrogen adsorption and SEM. Reductions of micropore surface area and micropore volume of Na-A zeolite were observed after modification with zinc oxide. H2S adsorption capacity was the highest, 15.75mgS/g sorbent, when 20wt% ZnO was loaded on Na-A zeolite. Reduction in adsorption capacity was observed when wt% ZnO increased above 20wt%.

Dynamic laser speckle technique as an alternative tool to determine hygroscopic capacity and specific surface area of microporous zeolites

Adsorption phenomena have several technological applications such as desiccants, catalysts, and separation of gases. Their uses depend on the textural properties of the solid adsorbent and the type of the adsorbed liquid or gas. Therefore, it is important to determine these properties. The most common measurement methods are physicochemical based on adsorption of N2 to determine the surface area and the distribution of pores size. However these techniques present certain limitations for microporous materials. In this paper we propose the use of the Dynamic Laser Speckle (DLS) technique to measure the hygroscopic capacity of a microporous natural zeolite and their modified forms. This new approach based on the adsorption of water by solids allows determine their specific surface area (S). To test the DLS results, we compared the obtained S values to those calculated by different conventional isotherms using the N2 adsorption-desorption method.

Utilization of iron ore tailing for the synthesis of zeolite A by hydrothermal method

The iron ore tailing (IOT) is an industrial waste, in which large accumulations represent a serious environmental threat. To reduce the environmental burden and improve the economic benefits, the science and industry focus on the transformation of IOT into new functional materials. In this study, the zeolite A was synthesized from IOT without acid leaching purification. The IOT and zeolite A were studied by XRD, XRF, XPS, SEM, and simply BET. As a result of the hydrothermal reaction, zeolite A was synthesized from the IOT. It was shown that the experimental conditions (SiO2/Al2O3, Na2O/SiO2, and H2O/Na2O) have a significant influence on the type of zeolite and its content in the synthetic products. The calcium ion-exchange capacity and the BET surface area of zeolite A product closely similar to that of the commercial 4A zeolite and superior to the zeolite A synthesized by traditional method discussed in this paper. The research result indicates that the zeolite A can be prepared from IOT and it can be reduce calcium ion as water softener.

Wet impregnation of silver oxide on Lampung natural zeolite as an adsorbent to produce oxygen-enriched air using PSA technique

High purity oxygen can be used for various things. Oxygen purification method to be applied on this research is the Pressure Swing Adsorption (PSA) technique. The adsorbent that would be used is a natural zeolite, namely ZAL (Zeolite Alam Lampung). Natural zeolite has non-polar properties, so it will adsorb gas with high quadruple moment, which is nitrogen. The varied variable is the size of adsorbent and the concentration of H2SO4. The sizes are 18-35 mesh, 35-60 mesh, and 60-100 mesh. While the H2SO4 concentration are 1M, 2M and 3M. Size of ZAL, and the concentration of sulfuric acid (H2SO4) were varied to get the optimum value. The adsorbent will be activated in aqua demine, H2SO4, NaOH, and through a calcination process. The purpose of this pre-treatment was to remove the impurities and to increase the specific surface area of zeolite. Moreover, ZAL will also be modified by wet impregnation technique using AgNO3 solution with 1%-wt loading nominal. The morphology, composition, and crystal phase were characterized by BET, scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX). The result of the adsorption process was analyzed by using GC (Gas Chromatograph). ZAL 35-60 mesh 1M showed the best performance on adsorbing nitrogen, with its lowest peak at 60356 μV. The result of this research suggested that ZAL itself has the main role on adsorbing nitrogen, while AgxO did not give any significant effect