Modified Natural Zeolites as Catalysts for Catalytic Reduction of NO with COmMain Components of Exhaust Gases

The study of oxidized-reduced properties of modified natural zeolites from deposits of Georgia--clinoptilolite and mordenite in reaction of reduction NO with H2, NH3, CH4 and especially CO was carried out for the purpose to obtain effective catalyst for afterburning of toxic components of automobile exhaust. The activity of zeolites essentially depends on nature of cation and temperature of reaction and slightly depends on structure of zeolite and ratio of reactants. The introduction of copper and iron ions in preliminary decationated clinoptilolite and mordenite causes growth of conversion degree of nitrogen and carbon monoxides almost on a degree, especially in low temperature interval. The reaction between NO and CO molecules proceeds in coordinative sphere of TM cations through formation ofnitrosyl and carbonyl complexes.

Effect of Natural Zeolite on Pore Structure of Cemented Uranium Tailings Backfill

The use of some environmental functional minerals as backfill-modified materials may improve the leaching resistance of cemented uranium tailings backfill created from alkali-activated slag(CUTB),but these materials may participate in the hydration reaction of the cementitious materials,which could have a certain impact on the pore structure of the CUTB,thus affecting its mechanical properties and leaching resistance.In this paper,natural zeolite is selected as the backfill-modified material,and it is added to alkali-activated slag paste(AASP)and CUTB in cementitious material proportions of 4%,8%,12%,and 16%to prepare AASP mixtures and CUTB mixtures containing environmental functional minerals.After the addition of natural zeolite,the porosity of the CUTB generally increases,but when the content is 4%,the porosity decreases to 22.30%.The uniaxial compressive strength(UCS)of the CUTB generally decreases,but the decrease is the smallest when the content is 4%,and the UCS is 12.37 MPa.The addition of natural zeolite mainly reduces the number of fine pores in the CUTB,but the pores with relaxation times T_(2)of greater than 10 ms account for about 10%of the total pores,and there are a certain number of large pores in the CUTB.The main product of alkali-activated slag is calcium(alumino)silicate hydrate(C-(A)-S-H gel).When natural zeolite is added,the hydration products develop towards denser products with a high degree of polymerization and the formation of low polymerization products is reduced.This affects the internal fracture pores of the hydration products and the interface pores of the CUTB,has an irregular effect on the pore characteristics of the CUTB,and influences the UCS.

Adsorption and Desorption of Natural Zeolite on NH_4^+

The adsorption and desorption kinetic of natural zeolite on NH4＋ was stud-ied by lab analysis. The results showed that the adsorption and desorption kinetic of natural zeolite on NH4＋ coincided with the first-order kinetics, modified Freundlich equation, parabolic diffusion model, and heterogeneous diffusion model. The desorp-tion of the adsorbed NH4＋ was far rapider than the adsorption, which can be fin-ished within 60 min.

Hydro-Adsorption Study by Dynamic Laser Speckle of Natural Zeolite for Adsorbent and Fertilizer Applications

The dynamic behavior caused by hydro-adsorption process of materials based on a rich mineral clinoptilolite together with their acidic, basic and calcinated forms has been studied by the dynamic laser speckle (DLS) technique. We propose a modified Peleg’s equation to improve fitting of DLS data. Textural (BET), structural (XRD) and spectroscopic (FTIR) properties were also studied and compared. We demonstrated that DLS was the most sensitive, simple and inexpensive method for comparing the performance of adsorptive materials with slightly modified surfaces. It also allowed the correlation with physicochemical properties.

Removal of Orthophosphate from Aqueous Solution Using Natural Zeolite

This study was focused on orthophosphate adsorption on natural zeolite which was obtained from South of Thailand and has been carried out by Vanadomolybdophosphoric Acid （VMPA） and using spectrophotometry technique. The phosphate solution were prepared artificially by adding certain quantities of KH2PO4 in water at the initial orthophosphate concentration of 5, 10 and 20 mg/L. While the adsorbent quantity was 1g of natural zeolite per 50 mL, aqueous solution NaOH IN and HCI IN solutions were used as pH regulators. The effect of equilibrium pH, adsorbent mass and contact time was studied. The results showed that natural zeolite adsorption efficiency was 99.18%, 99.33% and 99.02% （5, 10 and 20 mg/L）, respectively, at pH of 12 and a contact time of 30 minutes at 298 K. Moreover, the isotherm can be used to evaluate the capacity and nature of the interaction between a sorbent and a sorbate. This work considers the Langmuir and Freundlich isotherm. Based on the R2 of adsorption isotherm studies, the adsorption data for phosphate fitted well the Freundlich isotherm for natural zeolite （R^2=0.99）, with multi-layer adsorption. The results are in good agreement with recent experimentl data.

Morphological Assessment of the Small Intestine of Broilers Fed Dietary Natural Zeolite Including Plant Extract

Many kinds of feed additives （e.g., probiotics, prebiotics, antibiotics, etc.） can be used in chicken diets to stimulate intestinal morphological maturation and, consequently, intestinal function. The aim of this trial was to investigate the possibility that natural zeolite including plant extract （ZEM） could encourage the hypertrophy of intestinal villi and the absorptive function of epithelial cells in broiler chickens. At 7 days old, 64 male Marshall Chunky broilers were divided into four groups, each with four replicates of four chickens. The birds were fed a basal mash diet supplemented with ZEM at 0% （control）, 0.05%, 0.1%, and 0.2% for 42 days. At 49 days old, four chickens from each treatment were killed to obtain intestinal samples. Morphological intestinal assessment was conducted using both a light and a scanning electron microscope. A tendency to increased villus height and cell area could be observed throughout the intestinal segments of the broilers fed ZEM. Particularly, the villus height in the duodenum was significantly increased （P 〈 0.05） in the 0.05% ZEM group when compared with the control group. The area of the villus cells tended to be higher in the ZEM groups in all intestinal regions and showed a significant increase （P 〈 0.05） in the ileal part of the 0.2% ZEM group. Also, the assessment of cells mitosis in the intestinal crypts showed significantly higher numbers （P 〈 0.05） in all levels of ZEM groups in the duodenum and a tendency to increase in value in the jejunum and ileum, as compared with the control group. More protuberated cells and multi-cell clusters were found in the ZEM groups than in the control group, resulting in a rough cellular surface. In conclusion, the present study might suggest that the intestinal villi and epithelial cells on the villus apical surface are hypertrophied in the ZEM groups, and that intestinal villi adapt to enhance their absorption capacity by increasing the absorptive surface area. These results are indicated that ZEM can provide effective nutritive value when used as a feed additive.

Sono-Transesterification of Kapok Seed Oil with CaO:BaO-(x:y)/Active Natural Zeolite Catalyst

Kapok seed oil is an environmentally friendly biodiesel feedstock.The problem of the best catalyst for transester-ification of Kapok seed oil still continues today.The research developed a base-heterogeneous catalyst with the effect of ultrasonic waves during transesterification.So,the study aims:(1)to determine the type of natural zeolite used,(2)to determine the characteristics of the synthesized CaO:BaO/ANZ catalyst,and(3)to determine the effectiveness of the CaO:BaO/ANZ catalyst in the biodiesel production process through sono-transeste rification of kapok seed oil.The research stages consisted of:(1)activation of natural zeolite and its characterization,(2)preparation of CaO:BaO/ANZ catalyst,(3)characterization of CaO:BaO/ANZ catalyst,(4)esterification and uti-lization of catalyst in the transesterification,(5)analysis of transesterified products.The results showed that the natural zeolite type from the southerm area of Malang is mordenite(MOR)type.Then,after the natural zeolite was impregnated,the obtained catalyst compositions were CaO:BaO-9:9/ANZ,CaO:BaO-14:9/ANZ,and CaO:BaO-4:11/ANZ with a surface area of 129.7;124.6;128.5 m^(2)/g,and acidity of 1.037;0.254;and 0.685 mmol/g,respectively.The best catalyst for transesterification of kapok seed oil was CaO:BaO-9:9/ANZ,which resulted in a biodiesel yield of 73.6%with a density of 889.6 kg/m^(3) and kinematic viscosity of 2.987 cSt.The characteristics of the produced biodiesel meet requirement of SNI 7182:2015.

Effect of the Composite of Natural Zeolite and Fly Ash on Alkali-Silica Reaction

The effect of the composite of natural zeolite and fly ash on alkali-silica reaction (ASR) was studied with natural alkali-reactive aggregate and quartz glass aggregate respectively.The expansive experiment of mortar bar and concrete prism was completed.The results show that ASR can be suppressed effectively by the composite of natural zeolite and fly ash.

Characterization and Modification of Indonesian Natural Zeolite for Hydrocracking of Waste Lubricant Oil into Liquid Fuel Fraction

Modification and characterization of natural zeolite under some various methods for hydrocracking catalyst of waste lubricant to gasoline and diesel fractions have been conducted. Natural zeolite from Klaten was activated using hydrothermal treatment at temperature 500 ℃ for 6 h （produced ZAAHd）, the ZA sample was treated with hydrothermal followed by Microwave （produced ZAAHdM）, the ZA sample was treated with HCI 3 N at temperature of 90 ℃ for 30 min （produced ZAAH）, the ZAAH sample was heated in to microwave （produced ZAAHM）, the ZAAHM was treated hydrothermal （produced ZAAHMHd）, the ZAAHMHd sample was heated in to microwave （produced ZAAHMHdM）, soaking of natural zeolit activated by HCl-microwave-hydrothermal-microwave in NH4NO3 1 N which was stirred using stirer at room temperature for 24 h （produced ZAAHMHdMN） and the ZAAHMHdMN sample was heated into microwave （ZAAHMHdMNM）. The heating process by microwave was conducted at 550 watt for 15 rain. Catalyst characterization involved determination of the number of total acid sites using gravimetric method with vapour adsorption of NH3 and pyridine, catalyst crystallinity by XRD （X-ray diffraction） and TO4 （T= Si and AI） site by infra red spectrophotometer （IR）. Hydrocracking of waste lubricants oil was performed in a fixed bed reactor of stainless steel at temperature of 450 ℃, H2 flow rate of 15 mL/min., feed/catalyst ratio of 5. Liquid products of the hydrocracking were analyzed using GC （gas chromatography）. The characterization results showed that various modification of natural zeolite increased acidity and dealumination degree of the catalysts. Products of the hydrocracking were liquid, coke, and gas fractions. Liquid products consisted of gasoline fraction （C5-C12）, diesel fraction （C12-C20）, and heavy oil fraction （〉 C20）.Thc conversion of liquid products was increased with the increase of catalyst acidity. The greatest liquid product conversion was produced by the ZAAHMHdMNM catalyst, i.e., 56.80%, with selectivity towards gasoline, diesel, and heavy oil fractions was 88.37%, 8.61% and 3.02%, respectively. The increase of catalyst acidity increased the selectivity of gasoline fraction.

Obtaining and Reviewing X-ray Diffraction Analysis of the Uranium Catalyst SAPO-U, W, V Based on Natural Zeolite Chankanayskoe Deposits for the Oxidation of S02 to S03

We first obtained by impregnating the zeolite with salts U, W and V and examined the X-ray uranium catalyst SAPO-U, W, V based on natural zeolite Chankanayskogoe deposits for the oxidation of SO2 to SO3.

Feasibility of Natural Zeolite for Heavy Metal Stabilization in Municipal Solid Waste Incineration Fly Ash: A Novel Approach

The current study investigated the sorption process of heavy metals, especially lead (Pb2+) and Zinc (Zn2+), in Municipal Solid Waste Incineration (MSWI) fly ash applying natural zeolite, namely mordenite, as an inexpensive adsorbent to assess its feasibility for the treatment of fly ash. Batch experiments were performed to investigate the effects of the influential parameters, such as metals initial ion concentration, dosage of adsorbent, liquid to solid (L/S) ratio, and equilibrium concentration of metal on the immobilization of Pb2+ and Zn2+, in a novel approach. Heavy metals removal efficiency increased with increasing the dosage of mordenite influenced by the media-specific surface area. Heavy metals adsorption is ascribed to various mechanisms of ion exchange and adsorption processes. The Langmuir and Freundlich isotherm models were investigated using the adsorption data. The adsorption process describes better in the Freundlich isotherm model compared to the Langmuir isotherm model with a high determination co-efficient (R2), especially for the adsorption of Pb2+. In addition, the affinity of mordenite to Pb2+ was shown to be higher than that of Zn2+. This allows the use of mordenite to capture of Pb2+ in MSWI fly ash. Results raise expectations about using mordenite as a low-cost material for treating MSWI fly ashes. The results show that heavy metal (Pb2+ and Zn2+) removed by mordenite adsorbent is practical and effective. In order to achieve the higher efficiency on heavy metal stabilization in MSWI fly ash, additional experiments are necessary.

Preparation of Ethyl 4-Nitrobenzoate Using Ultradispersed Natural Zeolite Catalysts, Ultrasound and Microwave Irradiation

The new possibilities of preparing the ethyl 4-nitrobenzoate by esterification of 4-nitrobenzoic acid (4-NBA) with ethanol under argon at 80°C are shown;particularly, over catalysts: on micrometric (4.8 - 7.0 μm) or ultradispersed crystallites (290 - 480 nm) of hydrogen forms of nanoporous natural zeolites H-CL, H-MOR, H-HEU-M, H-PHI and under irradiation of the reaction mixture with ultrasound (US, 37 kHz, 330 W, 2 h) or microwaves (MW, 2450 MHz, 300 W, 2 h). Ultradispersed crystallites of zeolite catalysts were prepared from hydrogen forms of parent natural zeolites by their treatment with US or MW. In the esterification, the synergism of the actions of catalysts and MW or US was revealed;wherein on the ultradispersed best catalysts H-HEU-M and H-MOR conversion of 4-NBA and yield of ethyl 4-nitrobenzoate reached up to 70% and 67%, respectively. GC/MS, FTIR, NMR methods were used in the study.

Removal of Ag(I) from Aqueous Solution by Japanese Natural Clinoptilolite

The present study examined the adsorption of silver ion in aqueous solution onto natural clinoptilolite zeolite from Futatsui Mine, Akita Prefecture, Japan. The effects of various parameters, i.e., solution pH, adsorbent dosage, adsorption time, silver ion solution concentration, and temperature, on silver ion adsorption process onto clinoptilolite were examined. Additionally, the thermodynamics of the silver ion adsorption process was investigated. The optimum pH for silver adsorption was determined to be around 4.0. The adsorption process could be well described by the Langmuir isotherm model. The calculated maximum adsorption capacity was 0.64 mmol/g. Adsorption kinetics studies were also conducted. The results showed that the adsorption process preferentially followed the pseudo-second-order kinetics model over the pseudo-first-order model. Furthermore, with decreasing aqueous solution temperatures, the adsorption kinetics became slower and the amount of silver ion adsorbed increased. The thermodynamic values, ΔG0, ΔH0, and ΔS0, indicated that adsorption was an exo-thermic and spontaneous process.

A Novel Process of CO_(2) Reduction and CO_(2) Sequestration Through an Innovative Accelerated Carbonation Technique

The efiect of an innovative accelerated carbonation curing technique was evaluated on concrete containing natural zeolite powder and fine aggregate as partial replacement to alleviate the CO_(2) emission up to a certain extent from the concrete production industry and improve sequestration of CO_(2) into the concrete matrix in a stable form.An accelerated carbonation curing was accomplished by subjecting the concrete specimens to 0.5 and 0.75 M concentrations of sodium bicarbonate(NaHCO_(3)) solutions up to a curing age of 180 days after the initial 28 days of normal water curing.Tests for carbonation depth,pH value,compressive strength,calcium carbonate(CaCO_(3))content,X-ray difiraction,and thermogravimetric(TGA)analyses and Fourier transform infrared spectroscopy(FTIR)were performed to measure the extent of carbonation.The obtained results showed an increment in average compressive strength for the zeolite concrete(ZLC)mixes exposed to accelerated carbonation curing.The ZLC mixes exposed to increasing NaHCO_(3) solution concentration and exposure period exhibited greater carbonation depth and decreased pH at each depth interval indicating higher CO_(2) sequestration within the concrete matrix.The results obtained from the microstructural analysis(XRD,TGA,and FTIR)and CaCO_(3) content measurements confirm that the higher amount of CaCO_(3) formation provides a clear indication of the carbonation enhancement and CO_(2) sequestration within the concrete matrix and in turn contributing to the global warming reduction.

The effect of capping with natural and modified zeolites on the release of phosphorus and organic contaminants from river sediment

A microcosm system that included river sediment,water and different zeolite capping materials(natural zeolite,surfactant-modified zeolite(SMZ),or aluminum modified zeolite(AMZ))was designed to study the effect of capping on the release of phosphorus and three organic pollutants(phenol,pyridine,and pyrene)from the sediment to the overlying water over the course of three month.For the same amount of the three capping materials,the efficiency of phosphorus inactivation was in the order of SMZ>AMZ>natural zeolite.The inactivation of phosphorus was mainly caused by the covering effect,co-precipitation and adsorption by the capping materials.The different zeolites gave different results for the release of phenol,pyridine,and pyrene from the sediment.When natural zeolite was used as the capping material,there was no effect on the release of pyrene and pyridine,whereas capping the sediment with SMZ or AMZ inhibited the release of pyrene and pyridine but to different extents.However,for controlling the release of phenol from the sediment,aluminum modified zeolite was the most efficient material,whereas no effects were observed when natural zeolite or SMZ were used.The different capabilities of the zeolite materials for controlling the release of different organic pollutants are related to the differences in the electrical properties of these pollutants.

Using a zeolite medium biofilter to remove organic pollutant and ammonia simultaneously

A pilot scale zeolite medium biological aerated filter(ZBAF) was designed and used to treat municipal wastewater. It showed that ZBAF could simultaneously remove chemical oxygen demand(COD), ammonia-N and turbidity to satisfied degree at a hydraulic retention time(HRT) of 0.95 h. Their average removal efficiencies were 73.9%, 88.4% and 96.2% with the corresponding average effluent concentrations of 43.4 mg/L, 3.5 mg/L and 3.7 NTU, respectively. These effluent items met with the water quality standard of the treated water reused for cooling water. The COD removal volumetric loading rate increased proportionally with its applied volumetric loading rate with its maximum of 7.1 kg/(m 3·d). Ammonia-N removal loading rate also increased proportionally with its applied loading rate at HRT of longer than 0.95 h and the feasible maximum removal loading rate was 0.9 kg/(m 3·d). The COD loading rate did not affect the ammonia-N removal efficiency significantly when it was lower than 5.5 kg/(m 3·d). ZBAF has good application prospect for its low cost and high removal efficiency in the future.

Advanced regeneration and fixed-bed study of ammonium and potassium removal from anaerobic digested wastewater by natural zeolite

Highly efficient regeneration of natural zeolite was developed in conjunction with the removal of high concentrations of ammonia and potassium from the reverse osmosis effluent of anaerobic-digested wastewater by fixed-bed ion exchange.The elution and uptake behavior of ammonium and potassium in the fixed bed were studied.Both batch desorption tests and on-column regeneration were conducted to develop an optimum regeneration condition compatible with the wastewater requirements.The effectiveness of ammonium elution increased with increasing alkaline concentration.The increase of salt dose significantly enhanced the ammonium maximum in the elution solution.Complete ammonium elution was achieved in 6 bed volumes（BV） when the alkaline and salt concentrations were respectively 0.1 mol/L and 18.6 g/L at a flow rate of 2.5-3.0 BV/hr.Due to the higher affinity of potassium with natural clinoptilolite,complete potassium elution was not achieved in all cases.

Effects of natural zeolite and sulfate ions on the mechanical properties and microstructure of plastic concrete

One of the strategic materials used in earth-fill embankment dams and in modifying and preventing groundwater flow is plastic concrete(PIC).PIC is comprised of aggregates,water,cement,and bentonite.Natural zeolite(NZ)is a relatively abundant mineral resource and in this research,the microstructure,unconfined strength,triaxial behavior,and permeability of PIC made with 0%,10%,15%,20%,and 25% replacement of cement by NZ were studied.Specimens of PIC-NZ were subjected to confined conditions and three different confining pressures of 200,350,and 500 kPa were used to investigate their mechanical behavior and permeability.To study the effect of sulfate ions on the properties of PIC-NZ specimens,the specimens were cured in one of two different environments:normal condition and in the presence of sulfate ions.Results showed that increasing the zeolite content decreases the unconfined strength,elastic modulus,and peak strength of PIC-NZ specimens at the early ages of curing.However,at the later ages,increasing the zeolite content increases unconfined strength as well as the peak strength and elastic modulus.Specimens cured in the presence of sulfate ions indicated lower permeability,higher unconfined strength,elastic modulus,and peak strength due to having lower porosity.

Zeolite diagenesis and its control on petroleum reservoir quality of Permian in northwestern margin of Junggar Basin,China

Recently, silicate diagenesis has been the focus of many studies because of its impact on porosity and permeability in sedimentary rocks. In the process of diagenetic evolution, the crystallization, cementation, and corrosion of zeolite （as a diagenetic mineral） have different effects on properties of Permian reservoirs in the study area. In the Permian sediments in the no,inwestern margin of the Junggar Basin, Zeolite minerals have formed during diagenesis in an open hydrologic system, related to the hydration of abundant volcanic glass. Chemical property of groundwater, pH of pore water, cation property and ratios have directly influenced the transformation among various zeolites and the dissolution of zeolite mineral. The main species of zeolite include analcime, heulandite, and laumontite. Transformations of these minerals during diagenesis are： volcanic glass→ clinoptilolite→analcime→heulandite→laumontite. Corrosion of analcime obviously improved reservoir quality. Extensive heulandite cementation developed and intensively reduced reservoir pore spaces. Early zeolite cementation protected pore structure against compaction and provided substance for late dissolution. The dissolution of analcime was closely related with the organic acid recharged by hydrocarbon source rocks and the NaHCO3 type formation water in the Permian, and was sensitive to permeability of rocks. Within the CaCl2 type formation water, heulandite and laumontite were hardly dissolved. In the study area, the belt with dissolved analcime is the area for the development of secondary pores and favorable reservoirs.

An active and selective heterogeneous catalytic system for Michael addition

Potassium fluoride doped natural zeolite was found to be an efficient and selective solid base catalyst for 1,4-Michael addition. The catalyst is easily prepared and the workup procedure simplified by simple filtration.All products were obtained in high yields as well as short reaction times.