Amount Of Zeolite Research Articles

제올라이트에 의한 말라카이트 그린의 흡착특성

Malachite green is used a dye but malachite green is harmful toxic substance. In this study, the adsorption cha- racteristics of zeolite has been investigated for the adsorption of malachite green dissolved in water. The effects of initial dye concentration, contact time, pH and temperature on adsorption of malachite green by a fixed amount of zeolite have been studied in batch adsorber and fixed bed. The adsorption equilibrium data are successfully fitted to the Freundlich isotherm equation in the temperature range from 25 to 45 ℃. The estimated values of k and β are 23.60-46.88, 0.225-0.347, respectively. The mechanism of the adsorption process was determined from the intraparticle diffusion model. The effects of the operation conditions of the fixed bed on the breakthrough curve were investigated. When the inlet concentration and initial flow rate of malachite green are increased, the corresponding adsorption breaktime appears to decrease. Breaktime increased with increasing bed height and length of adsorption zone showed similar patterns.

Effect of addition of zeolite to iron-based activated-carbon-supported catalyst for Fischer–Tropsch synthesis in separate beds and mixed beds

In-reactor upgrading of the products of Fischer–Tropsch (FT) reactions using synthesis gas was studied by adding zeolite ZSM-5 to a supported iron-based FT catalyst. The effects of ZSM-5 amounts and bed arrangements on the product distribution were investigated. Product profiles were analyzed for changing the ZSM-5 weight from 50 to 200% of the FTS amount. Oligomerization, aromatization, isomerization, and cracking reactions are enhanced with increasing ZSM-5 weight. The base catalyst showed no selectivity toward aromatic compounds, but addition of ZSM-5 formed C7–10 aromatic compounds. Long-chain hydrocarbon molecules (C13+) formed by the base catalyst are effectively cracked, and the products are isomerized on the ZSM-5 catalyst surface. Two catalyst-bed configurations were used: separate-bed and mixed-bed. Both arrangements show conversion of alcohols to hydrocarbons and water. The separate-bed arrangement gave higher conversions of CO and H2, and higher yields of liquid hydrocarbons. The relative decline in FT activity for the mixed bed is probably due to metal migration from FT catalyst to ZSM-5, as confirmed by energy-dispersive X-ray spectroscopy of the spent ZSM-5. The maximum amount of i-C5–12 plus aromatics (a measure of high-octane gasoline-range hydrocarbons) is formed in the separate bed using equal amounts of zeolite and base catalyst.

Effect of varied quantities of zeolite on the reduction of polycyclic aromatic hydrocarbons in tobacco smoke

This research was carried out to determine the possibility of total and selective reduction of polycyclic aromatic hydrocarbons (PAHs) content in cigarette smoke by applying different amounts of zeolite directly to the cigarette blend. Zeolite catalysts CuZSM-5 were applied in the form of suspension to the cut tobacco blend in the quantities of 1 and 3%. After the equalization of the blend, the cigarettes were rolled on the cigarette making machine type MOLINS–9. The cigarettes were smoked according to the standard of ISO 3308 procedure. The smoke condensate which was extracted from Cambridge filter with methanol was analyzed by gas chromatography-microscopy (GC-MS). The obtained results indicated that there is a possibility of effective and selective catalytic reduction of PAHs in tobacco cigarette smoke. The determined reduction degree for the PAHs was 35.78 to 40.88%. The decrease of PAHs was proportional to the quantity of the zeolite added. CuZSM-5 showed a certain selectivity, especially towards fluoranthene (reduction ratio was 55.25:77.96%) and acenaphthylene (reduction ratio was 42.39:71.15%). It is possible to apply zeolite in the form of suspension to factory-made cigarettes because it does not affect the operation of machinery, especially the work of a cigarette maker.

Cr(VI) retention and transport through Fe(III)-coated natural zeolite

Cr(VI) is a group A chemical based on the weight of evidence of carcinogenicity. Its transport and retention in soils and groundwater have been studied extensively. Zeolite is a major component in deposits originated from volcanic ash and tuff after alteration. In this study, zeolite aggregates with the particle size of 1.4–2.4mm were preloaded with Fe(III). The influence of present Fe(III) on Cr(VI) retention by and transport through zeolite was studied under batch and column experiments. The added Fe(III) resulted in an enhanced Cr(VI) retention by the zeolite with a capacity of 82mg/kg. The Cr(VI) adsorption on Fe(III)-zeolite followed a pseudo-second order kinetically and the Freundlich adsorption isotherm thermodynamically. Fitting the column experimental data to HYDRUS-1D resulted in a retardation factor of 3 in comparison to 5 calculated from batch tests at an initial Cr(VI) concentration of 3mg/L. The results from this study showed that enhanced adsorption and retention of Cr(VI) may happen in soils derived from volcanic ash and tuff that contains significant amounts of zeolite with extensive Fe(III) coating.

Evaluation of Pathological Effects in Broilers During Fumonisins and Clays Exposure

This study was conducted to evaluate the possible protector effect of bentonite and zeolite in Bovans chicks fed a diet containing 59 mg kg(-1) of fumonisin B1 (FB1) during 3 weeks. A total of 200 one-day-old male chicks were treated varying the amount of bentonite and zeolite. Chick weight was registered weekly. At the end of the experiment, all the chicks were killed, and the livers were analyzed for gross examination and histopathological changes. Plasmatic activity of alanine amino transferase and aspartate amino transferase (AST) were also determined. Sphinganine and the sphinganine-to-sphingosine ratio in serum were evaluated. Both, bentonite and zeolite showed a protector effect against FB1 adsorption in the digestive tract of chicks. Chicks fed with FB1-contaminated feed, amended either with zeolite or bentonite, were heavier, and no macroscopic lesions were observed in the livers. AST activity might be considered as an indicator for FB1 exposition because AST levels were affected when only FB1 was present in the basal diet. These results indicate that both, zeolite and bentonite can be added into feed to diminish the effects of FB1.

Effect of zeolite on saturated hydraulic conductivity and crack behavior of silty clay paddled soil

The addition of zeolites to soil modifies soil physical and chemical properties. The objectives of this research were to study the effect of zeolite on saturated hydraulic conductivity, K s, and crack behavior in a silty clay paddled soil. Soil samples were mixed with 0, 4, 8 and 12 g kg−1 of zeolite for K s determination, and 0, 2, 4, 8 and 12 g kg−1 for soil crack measurements. Saturated hydraulic conductivity was measured using the constant head method. The results indicated that K s was significantly increased at a zeolite application rate of 8 g kg−1. Furthermore, an increase in zeolite content up to 8 g kg−1 decreased soil crack area after paddling and first rewetting. Higher amounts of zeolite (e.g. 12 g kg−1) increased crack density after the second rewetting. However, a 50% reduction in crack depth occurred with zeolite application rates of 8 and 12 g kg−1 in comparison with controls. Thus, a zeolite application rate of 8 g kg−1 is recommended for soil crack reduction in intermittent-flood irrigation. Furthermore, a relationship was obtained between crack area density (Ln), gravimetric soil water content and zeolite application rate. After the second irrigation, a relationship was also obtained between crack depth, gravimetric soil water content and zeolite application rate. Crack depth showed a positive and highly significant linear correlation with crack width.

Preparation and characterization of nanoparticle‐filled, mixed‐matrix membranes for the pervaporation dehydration of isopropyl alcohol

AbstractNovel polymeric mixed‐matrix membranes (MMMs) were prepared by the incorporation of different amounts of 13X zeolite into a sodium carboxymethylcellulose (NaCMC)/poly(vinyl alcohol) (PVA) blend matrix. The resulting MMMs were characterized by attenuated total reflectance–Fourier transform infrared spectroscopy to analyze the possible chemical reactions between NaCMC, PVA, zeolites, and glutaraldehyde. Scanning electron microscopy, differential scanning calorimetry, thermogravimetric analysis, and X‐ray diffraction were used to analyze the surface morphology, thermal stability, and crystallinity, respectively, of the membranes. Swellings studies were performed at 35°C, and we found that membranes containing 20 wt % zeolite showed higher values (960 kg m−2 h−1) at 17.5 wt % water in an isopropyl alcohol (IPA)/water mixture. Pervaporation (PV) experiments were also performed to evaluate the membrane performance in different compositions of the IPA/water mixture at 35°C. The mechanical properties were also tested, and we found that the optimum mechanical strength and percentage elongation at break were 42.24 N/mm2 and 3.38, respectively, for the membrane containing 15 wt % zeolite. The experimental results show that both the flux and selectivity increased with increasing zeolite content. The membrane containing 20 wt % zeolite showed the highest separation selectivity (5118) with a substantial flux of 0.121 kg m−2 h−1 at 35°C and with 10 wt % water in the feed; this suggested that the membranes could be used effectively to break the azeotropic point of the water–IPA mixture, so as to remove a small amount of water from IPA. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012

Hydrolysis of sucrose over composite catalysts

The hydrolysis of sucrose into glucose and fructose was carried out over composite catalysts at 80°C. These catalysts consisted of USY and Beta zeolites dispersed in polymeric matrices (PDMS and PVA). The swelling degree of polymers increased with the amount of zeolite immobilised in PDMS and PVA. This result can be explained by the increase in the polymeric matrix channelling. Additionally, the effective diffusivity of sucrose increases with the amount of USY and Beta zeolite that was dispersed in PDMS.The catalytic activity increases with the amount of zeolite dispersed in the polymeric matrix. The PVA composites showed higher catalytic activity than the PDMS ones.To study the catalytic stability of the Beta2/PVA catalyst, four consecutive batch runs were carried out with the same catalyst. The Beta2/PVA catalyst was recycled and reused with a negligible loss in its activity.

Highly regioselective di-tert-amylation of naphthalene over reusable H-mordenite zeolite

Highly regioselective di-tert-amylation of naphthalene using different alcohols can be achieved over a H-mordenite (HM) zeolite. For example, the tert-amylation of naphthalene using tert-amyl alcohol in cyclohexane over HM (Si/Al = 10) zeolite has been optimised to give a 70% yield of 2,6-dialkylnaphthalenes, of which 2,6-di-tert-amylnaphthalene was produced in 46% yield along with 2-tert-amyl-6-tert-butylnaphthalene (23%) and 2,6-di-tert-butylnaphthalene (1%). This has been achieved by varying the reaction time, temperature, pressure and amounts of tert-amyl alcohol and zeolite. No 2,7-dialkylnaphthalenes were seen under the conditions tried. The zeolites can be easily regenerated by heating and then reused.

Ammonia volatilization from urea at different levels of zeolite

Ammonia (NH3) loss due to hydrolysis of urea can be substantial. When applied to the soil, up to 50% NH3 volatilizes. This decreases urea-N use efficiency. The objective of this study was to minimize ammonia loss from urea using different levels of clinoptilolite zeolite. Six treatments were evaluated; (1) soil alone, (2) 2.60 g granular urea, (3) 2.60 g liquid urea, (4) 2.60 g liquid urea + 4 g of zeolite, (5) 2.60 g liquid urea + 8 g of zeolite and (6) 2.60 g liquid urea + 12 g of zeolite. The incubation study was conducted using close-dynamic air flow system method to measure the amount of NH3 released. At the end of this study, soils samples were analyzed for pH, exchangeable ammonium (NH4+) and available nitrate (NO3-) using standard procedures. When urea was applied in liquid form, NH3 loss was reduced when compared with granular urea, but not significantly different among the treatments with and without zeolite inclusion. Increase in soil pH was observed upon addition of higher amount of zeolite when compared with urea alone. High NH4+ content and low NH3 loss for T5 directly showed that high cation exchange capacity (CEC) of the amended soil due to inclusion of zeolite was responsible for retention of more NH4+ in the soil even though the soil pH was higher when compared with T1 and T2. Liquid urea mixed with zeolite reduced NH3 loss and increased NH4+ retention in the soil. Key words: Ammonia volatilization, granular urea, liquid urea, zeolite.

Zeolite 13X for adsorption of ammonium ions from aqueous solutions and hen slaughterhouse wastewaters

In this study adsorption efficiencies of various zeolites were tested for removal of ammonium ions from aqueous solutions. In the experiments performed with different initial ammonium concentrations, highest removal was obtained for Zeolite 13X so forthcoming studies were carried out with this zeolite type. The effects of initial NH4+ ion concentration, zeolite amount, pH and agitation time on adsorption efficiency were investigated with batch experiments. Langmuir, Freundlich and Dubinin–Radushkevich (D–R) models were applied to experimental data and calculated correlation coefficients were determined as 0.54, 0.93 and 0.89 for the models, respectively. Main energy of adsorption (E), calculated as 0.542kJ/mol, demonstrated physical characteristics of adsorption process. Optimal conditions determined for aqueous solutions were used also for hen slaughterhouse wastewaters. In kinetic calculations it was obtained that pseudo-second order reaction kinetic model was well-fitted for both synthetic solution and wastewater.

Investigation of using natural zeolite in brake pad

Brake pads in automobiles are made of composite materials composed of more than ten different ingredients. The choice of the friction material has an important impact on a vehicle’s braking performance. Drivers expect the brake system to stop the automobile under all possible conditions. In the present study, natural zeolite was used as a new material in brake pad. Zeolite has a silica ingredient which gives the pad materials a ceramic like behavior. Zeolite is ground to obtain the dust. Different amount of zeolite is used in the mix of other regular ingredients in brake pad. Newly formulated brake pad material with seven different ingredients has been tested under Friction Assessment and Screening Test (FAST). In this experimental study, the change of friction coefficient, the temperature of friction surface and the amount of wear were measured. In addition, micro-structural characterizations of braking pads were carried out using scanning electron microscopy (SEM).

제주 스코리아로부터 합성된 Na-P1 제올라이트에 의한 2가 중금속 이온의 제거특성

The removal performances of divalent heavy metal ions (<TEX>$Pb^{2+}$</TEX>, <TEX>$Cu^{2+}$</TEX>, <TEX>$Cd^{2+}$</TEX>, <TEX>$Sr^{2+}$</TEX> and <TEX>$Mn^{2+}$</TEX>) were studied using the Na-P1 zeolite synthesized from Jeju scoria in the batch and continuous fixed column reactor. The uptakes of heavy metal ions by synthetic Na-P1 zeolite decreased in the order of <TEX>$Pb^{2+}$</TEX> > <TEX>$Cu2^{2+}$</TEX> > <TEX>$Cd^{2+}$</TEX> > <TEX>$Sr^{2+}$</TEX> > <TEX>$Mn^{2+}$</TEX> based on the selectivity of each ion to ionic exchange site of Na-P1 zeolite for single and mixed solutions in batch or continuous fixed column reactor. For mixed solution, each heavy metal ion uptake was lower than that in single solution, and especially the uptake for <TEX>$Mn^{2+}$</TEX> decreased greatly. In batch reactor, the uptakes of heavy metal ions by synthetic Na-P1 zeolite were described by Freundlich or Langmuir equation, but they followed the former better than the latter. In continuous fixed column reactor, the maximum ion exchange capacity obtained for each of heavy metal ions, was about 90----- of that in batch reactor. The uptakes of heavy metal ions by synthetic Na-P1 zeolite increased with the increase of initial heavy metal concentration and solution pH, and the decrease of the amount and particle size of synthetic zeolite.

Lead Removal from Aqueous Solution by Natural and Pretreated Zeolites

Hazardous metal cations enter water through the natural geochemical route or from the industrial wastes. Their separation and removal can be achieved by adsorptive accumulation of the cations on a suitable adsorbent. In the present work, toxic Pb(II) ions are removed from water by accumulating it on the surface of natural zeolite in three different forms; one untreated and two treated samples, one sample treated with 2 M HCI solution and other is treated with 3 M NaOH solution. Natural zeolite is mainly composed of clinoptilolite, and mordenite, with amount of non-zeolite phase (smectite and illite) and C and CT opal. The adsorption experiments are carried out using a batch process in environments of different pH, initial Pb(II) concentration, interaction time and amount of zeolites. Treated zeolite samples show high exchange capacity for Pb(II) compared to untreated sample, however, acid-treated sample shows an exceedingly good exchange capacity. Equilibrium data fitted well with the Langmuir isotherm model with maximum adsorption capacity of 115, 126, and 132 mg g−1 of untreated natural zeolites, alkali-treated zeolites and acid-treated zeolites respectively. The rates of adsorption were found to confirm to pseudo-first order kinetic with good correlation and the overall rate of lead ions uptake.

PVC silver zeolite composites with antimicrobial properties

Poly(vinyl chloride) (PVC) composites containing increasing amounts (2–20%, w/w) of silver zeolite (SZ) were prepared by melt mixing and characterized by thermal, mechanical and rheological analyses. The addition of large amount of SZ did not influence the processability and the formability of the composites, if compared to neat plasticized PVC. The antibacterial activity of PVC SZ composites was tested on Escherichia coli and Staphylococcus epidermidis and resulted promising both in culture broth and on agar plate and also in sterile urine seeded with these strains, for simulation purposes. In sterile urine, composites induced a significant reduction (4–6 log units) of viability of both strains already at 24 h, inhibiting E. coli growth up to 20 days, whereas their antimicrobial action against S. epidermidis vanished within 5 days. The silver release in sterile urine was determined up to 20 days. It was found that the highest amount of silver ions was released during the first day (0.365 ppm), whilst from days 6 to 20 the silver release decreased, reaching a steady daily mean value of 0.02 ppm.

The effect of zeolite amount on the physical and mechanical properties of concrete

Concrete is one of the most commonly used materials in building construction and thus it is important to investigate its properties. For these purpose four different types of lightweight concrete has been produced by using different amount of zeolite used as an aggregate. The zeolites were obtained from around the Goldes town of Manisa province in Turkey. The ultrasound velocity, compressive strength, Schmidt hardness, flexural strength and elasticity module of those concrete have been measured. Ultrasonic velocity increases with increasing amount of zeolite, compressive strength, Schmidt hardness, flexural strength and elasticity module decreases depending on the amount of zeolite. Key words: Zeolite, aggregate, lightweight concrete, physical properties, mechanical properties.

Coral-like hydroxy sodalite particles from rice husk ash as silica source

Coral-like hydroxy sodalite (HS) particles were prepared from rice husk ash as silica source in the presence of other aqueous-based precursor materials following a simple process under hydrothermal condition at 90 °C for 15 h. The particles obtained at 90 °C for different times (6, 10 and 15 h) were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and field emission scanning electron microscopy (FESEM). The HS crystals along with a small amount of zeolite A particles were observed at 90 °C/6 h while phase pure HS particles were obtained at 90 °C for 10 and 15 h. The characteristic vibration bands of the HS particles were confirmed by FTIR spectroscopy. FESEM images showed that the HS particles obtained at 90 °C/15 h were coral-like morphology which were formed through the self-assembly of the smaller particles generated at the initial stage of reaction (6 and 10 h) under the same experimental conditions. A proposed mechanism for the formation of coral-like HS particles was also illustrated.

Consolidation and Hydraulic Conductivity of Zeolite-Amended Soil-Bentonite Backfills

The effect of zeolite amendment for enhanced sorption capacity on the consolidation behavior and hydraulic conductivity, k, of a representative soil-bentonite (SB) backfill for vertical cutoff walls was evaluated via laboratory testing. The consolidation behavior and k of test specimens containing fine sand, 5.8% (dry weight) sodium bentonite, and 0, 2, 5, or 10% (dry weight) of one of three types of zeolite (clinoptilolite, chabazite-lower bed, or chabazite-upper bed) were measured using fixed-ring oedometers, and k also was measured on separate specimens using a flexible-wall permeameter. The results indicated that addition of a zeolite had little impact on either the consolidation behavior or the k of the backfill, regardless of the amount or type of zeolite. For example, the compression index, Cc, for the unamended backfill specimen was 0.24, whereas values of Cc for the zeolite-amended specimens were in the range 0.19≤Cc≤0.23. Similarly, the k for the unamended specimen based on flexible-wall tests was 2.4×10-10 m/s, whereas values of k for zeolite-amended specimens were in the range 1.2×10-10≤k≤3.9×10-10 m/s. The results of the study suggest that enhancing the sorption capacity of typical SB backfills via zeolite amendment is not likely to have a significant effect on the consolidation behavior or k of the backfill, provided that the amount of zeolite added is small (≤10%).

A Study on the Characteristics of Zeolite-Enhanced Activated Sludge in the A/O Biological Nitrogen Removal Process

This paper mainly studies the use of the activated sludge process with zeolite to upgrade the traditional secondary water treatment plants. With the addition of an appropriate amount of zeolite, the living environment of several micro-organisms in the activated sludge can be improved, thus raising the activity and number of micro-organisms and increasing the level of nitrification. Simultaneously, it also can improve size distribution and structure of sludge particles, the settling property, thus reducing the specific resistance of sludge. However, excess doses of zeolite will increase the viscosity of the sludge, which will reduce the compression performance in sludge thickening. This is not favorable to the operation of the secondary sedimentation tank and the pipeline transport of sludge. Therefore, we suggest the further study of the lower doses of zeolite, to find the optimum effect and eliminate the negative ones.

Clavulanic Acid Adsorption Studies in Zeolites

Zeolites are crystalline inorganic solids containing aluminium, silicon and oxygen arranged in a highly regular structure, and they are usually used in separation processes. In this study, zeolites have been shown to act as adsorbents for clavulanic acid. Ion exchange with different compensating cations (Na+, K+, Ca2+, Ba2+, Mg2+, Sr2+) was used to modify the natural zeolite (NZ) and the synthetic faujasite (13X). Kinetic analysis of the adsorption of clavulanic acid indicated that the 13X-Na zeolite was the most appropriate for this purpose. Under equilibrium conditions, the retention by this zeolite was about 17.4% (C*/C0 = 0.826), with the amount of clavulanic acid adsorbed relative to the amount of zeolite employed (q*) being ca. 0.5 mg/g. The 13X-Na zeolite was characterized in terms of its Si/Al ratio (1.5), density (dz = 2.248 g/cm3), superficial area (SBET = 444.860 m2/g), total pore volume (Vpore = 0.308 cm3/g), micropore volume (Vmicro = 0.203 cm3/g) and particle porosity (ep = 0.69). Adsorption...