Amount Of Zeolite Research Articles

Compositional and textural evidences of Na-bentonite authigenesis in the Pellegrini lake deposit (Neuquen basin, Argentina)

Textural and compositional variations of Na-bentonites from the Pellegrini Lake deposit (Neuquén Basin) have been established, with special emphasis on petrographic features in order to better understand the genetic pathways in their formation. In this region, two bentonite beds named “white bentonite” and “green bentonite” are mined mainly for the oil and foundry industries. The genesis of these beds was studied using petrological (petrography, SEM and TEM), mineralogical (DRX, FT-IR, DTA-TGA, 27Al MAS NMR) and geochemical (ICP-AES) data from two quarries named COR and CA. The bentonites mainly consist of Na-montmorillonite, with lesser amounts of quartz, plagioclase, potassium feldspar, illite, zeolite, barite and gypsum. Mineralogical and petrographical evidence indicates that the authigenic smectite was formed by devitrification of unstable glass shards in a shallow coastal marine environment. Green bentonite would be the result of several episodes of volcanic ash-fall input from multiple eruptions with a higher degree of alteration uppermost in the bed. In this case, the alteration would have occurred in a reducing environment as evidenced by the greenish colouration of these bentonites, the Ce anomaly and the presence of pyrite. Meanwhile, white bentonite would have formed in a less restricted environment than green bentonite, as evidenced by the existence of intercalations of silt-sized grains and a higher amount of detrital grains in the clay groundmass transported probably by fresher waters. The presence of celestine, barite, halite and gypsum indicates evaporitic conditions after smectite formation. The observed secondary gypsum and iron staining of surfaces are much later processes. Green bentonite samples indicate a trachyandesite composition of the parent material, while the white bentonite suggests a parent material most related to a rhyodacite/dacite composition showing that the characteristics of the volcanism might have changed with time.

Estimation of catalytic cracking of vacuum gas oil by ZSM-5- and β-zeolite-containing two-layered and novel three-layered hierarchical catalysts using Curie point pyrolyzer

ZSM-5- and β-zeolite-containing two-layered hierarchical catalysts (2 L-Z and 2 L-β) were prepared using a template of malic acid and novel three-layered hierarchical catalysts were also prepared combining mesoporous silica derived from the gel skeletal reinforcement (GSR) method with hexamethyldisiloxane (HMDS) - acetic anhydride (AA) as reinforcing agents. 2 L-Z and 2 L-β catalysts contained mesoporous silica of 50 wt% and microporous zeolite of 50 wt% and were called 2 L-Z-(Z50) and 2 l-β-(Z50) in which the amount of zeolite is shown in parenthesis. 3 L-co-gel and 3 L-mix, two types of three-layered hierarchical catalysts, were prepared by making GSR-silica in the presence of a 2 L catalyst for the former and by combining GSR-silica-gel with 2 L catalyst for the latter. 3 L catalysts contained 50 wt% of the 2 L catalyst and 50 wt% large-mesoporous GSR-silica and revealed three layered properties of microporous zeolite, small mesoporous silica and large mesoporous silica. Signals of zeolite crystals and amorphous phase were observed in XRD measurement for 3 L catalysts. Both smaller size of mesopores and larger size of mesopores were observed in N2 adsorption-desorption measurement. Vacuum gas oil (VGO) was catalytically cracked using 2 L and 3 L hierarchical catalysts with the use of Curie point pyrolyzer (CPP) method. ZSM-5-containing 3 L catalysts exhibited the lower conversions than corresponding 2 L catalyst, kaolin-mixed catalyst and ZSM-5 single while 3 L-co-gel-β-(Z25), which included 25 wt% of β-zeolite, exhibited the highest activity among β-zeolite-containing catalysts. The higher selectivity for p-xylene in xylene mixture was detected in catalytic cracking using 3 L-co-gel-Z-(Z25) and 3 L-mix-Z-(Z25) catalysts. When the relative activity against XRD integral intensity and amounts of acid sites was plotted against average pore diameter derived from N2 adsorption-desorption measurement, the strong correlation was observed, suggesting that the intrinsic activity of active sites of zeolite could be related to the pore size of the whole catalyst.

Hydrodeoxygenation of linoleic acid using water as hydrogen source on Co/HB zeolite

Hydrodeoxygenation (HDO) is a critical step in upgrading biomass-derived feedstock to renewable fuels and valuable chemicals. Thus, preserving the environment through the use of agricultural waste. Water plays the role of solvent, reactant, or byproduct in biomass HDO reactions, which are catalyzed by Co/HB zeolite catalysts. In this investigation, The hydrodeoxygenation of linoleic acid was examined in a patch-packed-bed reactor with a beta zeolite range of (5-15) mg and catalyzed at a temperature range of 230-300 K for 2-3 h. Linoleic acid, an unsaturated fatty acid, was used in this work to create hydrocarbons in the diesel range, as well as to clarify the impact of zeolite quantity, temperature, and time on the yielded product, to produce biofuels from Linoleic acid by hydrodeoxygenation in the high-pressure reactor in the presence of the catalyst. The products are then characterized by gas chromatography-mass spectrometry (GC-MS). Based on the optimization results, it was determined that the hydrodeoxygenation reaction primarily eliminated the oxygen atoms from fatty acids. The yield of the intended products was 96.2% at the Co/HB zeolite amount (10% wt), high reaction temperature (270 ºC), and time (150 min) conditions.

Batch adsorption studies on copper removal from an aqueous solution using natural zeolite: Process optimization

Abstract The ability of natural zeolite to remove copper ions from an aqueous solution was examined. The research aims to optimize adsorption operational variables, which include the amount of zeolite, pH, contact time, and initial heavy metal concentration for copper removal using zeolite. The research was conducted in batch experiments. The ranges of operational conditions are as follows: 0.2 - 1.0 g of zeolite, pH 4 - 8, 2 - 60 minutes of contact time, and 5 - 50 mg/L of initial concentration of copper. The outcomes indicated that the percentage removal of copper using zeolite achieved the best performance at an optimized adsorbent dosage of 1.0 g, a pH of 6, a contact time of 20 minutes with 135 rpm, and an initial copper concentration of 5 mg/L. To sum up, zeolite is an efficient adsorbent that is capable of separating copper from water-based solutions.

Ultrasonically Assisted Electrocoagulation Combined with Zeolite in Compost Wastewater Treatment

In this paper, the possibility of combining electrocoagulation (EC), ultrasound, and the addition of zeolite for wastewater treatment was investigated for the first time. The following combinations of hybrid processes were tested: electrocoagulation with zeolite (ECZ), simultaneous electrocoagulation with zeolite and ultrasound (ECZ+US), and two-stage electrocoagulation with zeolite and ultrasound (US+Z - EC), carried out with three different electrode materials. The results show that the simultaneous assistance of ultrasound in the ECZ leads to a lower increase in pH, while the temperature increase is higher. Regarding the COD, the assistance of ultrasound is only useful for Zn electrodes in the two-stage US+Z - EC, while the reduction in voltage consumption occurs for Fe and Al electrodes. Ultrasonic assistance caused more damage to the anodes, but anode consumption was reduced for Al and Zn electrodes. The total amount of zeolite that can be recovered is between 55–97%, and recovery is higher in systems with higher turbidity reduction. Good settling ability is only achieved with Al and Fe electrodes in simultaneous performance. Taguchi’s orthogonal L9 array design was applied to analyze the effects of electrode material, process type, mixing speed, and time duration on COD decrease, settling velocity, electrode, and voltage consumption. The results show that the use of ultrasound does not contribute to the desired result and generally only has a favorable effect on voltage and electrode consumption, while it has no positive effect on settling ability or COD decrease. Furthermore, although longer times and higher mixing speeds negatively impact cost due to voltage and electrode consumption, it is advisable not to choose the shortest duration and lowest speed to obtain adequate wastewater treatment quality.

Advancing self-cleaning performance in metakaolin-based geopolymers through in-situ zeolite formation and TiO2 integration

The deterioration of self-cleaning properties of cementitious materials upon hydration was addressed by in-situ zeolite formation within metakaolin-based geopolymers. Pastes with varied in-situ zeolite content were formulated by adjusting the Si/Al ratio of initial raw materials and curing temperatures. The impact of in-situ zeolite formation on self-cleaning performance was systematically investigated through phase composition, optical property and microstructure analyses. Zeolite A formation notably enhances self-cleaning performance, despite contributing to higher band energy and lower Urbach energy. The increases in crystalline zeolite amount and matrix porosity enhances mass transfer capacity. The open pore structure of zeolite facilitates the formation of connective channels during particle growth, mitigating the “sheltering” effect of the surrounding media for photocatalysts and ensuring improved self-cleaning performance upon hydration. This study summarizes the synthesis conditions for zeolite A, providing mechanistic insights into in-situ zeolite formation in metakaolin-based geopolymers and emphasizes its promising potential for optimizing self-cleaning properties in cementitious materials.

Use of calcium zeolite as an absorption agent for arsenic and lead in mine tailings

Metallurgical processes in beneficiation plants, generate large quantities of waste called mining tailings, which are harmful to the environment and health due to the heavy metals present. These tailings are sometimes deposited in water effluents, close to mining production areas. Therefore, the purpose of the present investigation was to propose partial remediation of the exposed problem, with the use of zeolite, depositing this mineral on and under the mining tailings, carrying out 10 tests, with variation in the amount of zeolite, from 100 to 500 grams. The trials were subject to an action time of 30 days. The results obtained in the experimentation show that the test with 500 grams, placed at the bottom of the tailings, was the most efficient for the absorption of heavy metals, specifically with results of 43% in lead and 51% in arsenic, which benefits to the environment.

Moroccan heated clay-based geopolymer reinforced with date palm cellulose: microstructure characterization and mechanical/physical properties

AbstractThe objective of this research was to study the cellulose addition effect on the geopolymerization of heated clay. The clay, composed of illite, plagioclase and kaolinite, was heated at 700°C for 2 h and mixed with cellulose (up to 10 mass%). The mixtures were NaOH-activated, and shaped samples were aged at 83°C for 30 days. The cured samples were investigated by using X-ray diffraction, Fourier-transform infrared spectroscopy and scanning electron microscopy. The influence of the cellulose addition on the mechanical/physical properties was also evaluated. The results showed that zeolite ZK-14, hydrosodalite, sodium carbonate and a geopolymer composed of poly(sialate) units were formed in all cured samples. The relative amounts of zeolite and metakaolin evolved antagonistically, whereas that of illite slightly decreased with increasing cellulose content. Metakaolin and illite were involved in the geopolymerization process. Cellulose addition led to the improvement of the flexural strength of the samples and to porosity reduction. By contrast, water absorption was increased. The positive effect of cellulose on sample performance is explained on the basis of hydrogen bonding between the functional moieties of cellulose and the active sites of sample constituents, namely zeolites, metakaolin, illite and the geopolymer. As a filler, zeolite probably contributed to sample strengthening, and the detrimental impact of Na-carbonate was insignificant. Based on the results obtained, the composites could be used as binders for brick manufacturing or as lightweight mortars.

Zeolite for Increasing the Compressive Strength of Adobe in the Historical Site of Belqis

Abstract“Belqis” is a historical and archeological site located in Khourasan province in northeast of Iran close to the city of Esfarayen. This study was conducted to consider the composition of the soil used to make the adobe in these structures, which has been exposed to deterioration processes followed by accelerate erosion. In response to this problem, Zeolite was used as an additive to improve soil quality. The finegrained soil texture is full of sand and silt with small amounts of clay. Zeolites has been used in the study in the form of granules (maximum 5 mm). X‐ray diffraction (XRD) and X‐ray fluorescence (XRF) used to define chemical composition and crystalline phase. Scanning electron microscope (SEM) was used for Determination surface characteristics and morphology. The presence of sand in the soil of the region and its decrease in adhesion is the reason for the decrease the compressive strength of clay. The results showed that the amount of 6% zeolite is most effective in improving the compressive strength of adobe. This amount of zeolite increases the compressive strength of clay compared to the samples without zeolite.

Optimization of mortar self-healing performance-based on response surface methodology: A multifactor analysis of zeolites, crystalline admixtures, and water-to-binder ratio

To address the issue of concrete structures being prone to crack failure, this study employs the response surface method (RSM) to evaluate the impact of adding zeolites and crystalline admixture (CA) on the self-healing performance of mortar. Initially, zeolite amount, CA amount, and the water-to-binder ratio (W/B) are considered as response factors, using ultrasonic pulse velocity (UPV), electrical resistivity, and the self-healing rate as the response target values. UPV and electrical resistivity are used to monitor self-healing process, while self-healing rate quantifies healing of cracks. Subsequently, through designing experiments with RSM, a regression model is established, achieving multi-objective optimization of the mortar self-healing rate, and experimental validation is carried out for the optimized combinations. Finally, the mechanical properties of mortar specimens are studied, and scanning electron microscopy (SEM) and X-ray diffraction (XRD) are used to analyze the microstructure and crystal phase composition of the crack healing fillers. The quadratic polynomial model has a high degree of fit, and the error between the measured and predicted values is less than 10%, indicating the reliability of RSM in determining the optimal mix parameters for mortar self-healing. The SEM and XRD results further confirm that the moisture released by zeolites promotes the activation reaction of CA, generating a larger amount and more densely structured calcium silicate hydrate (C-S-H) gel. Moreover, the research results show that although incorporation zeolites diminishes mortar specimens' strength, incorporation zeolites promotes the generation of C-S-H gel within the cracks, attributable to activation reaction of CA, ultimately promoting crack healing and improving the strength of the mortar. Based on optimization analysis, the optimal amounts of zeolites, CA, and W/B were determined to be 20%, 4%, and 0.45, respectively.

CO2, CH4, and N2O emissions from dredged material exposed to drying and zeolite addition under field and laboratory conditions

Dredging, the removal of sediment from water courses, is generally conducted to maintain their navigability and to improve water quality. Recent studies indicate that dredging can significantly reduce aquatic greenhouse gas (GHG) emissions. These studies, however, do not consider the potential emission from the dredged material (sludge) in the depot. In addition, it is unknown if and how GHG emissions from sludge depots can be reduced. Here we present spatiotemporal variations of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) fluxes, as well as environmental variables from a sludge depot located in the Netherlands. Measurements were conducted monthly from the time the depot was filled until the sludge was dry and the depot was abolished. We also experimentally assessed the GHG mitigation potential of 1) keeping the sludge permanently inundated, and 2) the addition of different amounts of zeolite to increase sludge nitrogen binding capacity to reduce N2O emissions. In the depot and in the laboratory, a decrease in moisture content coincided with increased CO2 and N2O emissions while CH4 emissions decreased. We observed that permanent inundation reduced emissions (∼4 times less CO2-eq than in drying sludge). Adding zeolite lowered N2O fluxes from permanently inundated sludge but did not reduce total GHG emissions. During the depot's operational period, average CO2, CH4, and N2O fluxes were 5078, 27, and 5 mg m−2 d−1, respectively. GHG emissions from drying sludge occurred mainly in the form of CO2 (73% of the total CO2-eq emissions), with average GHG emission rates comparable to those reported for ditches and ponds. We estimate that approximately 14 tons of CO2-eq were emitted from the 0.011 km2 depot, which contained ∼20,000 m3 of sludge, during its entire operational period, and we argue that more studies are needed, considering different sludge origins, to expand our understanding of sludge depots.

Reducing CO/NO and absorbing heavy metals in self-sustained smouldering of high-moisture sludge by regulating inert media with low-cost natural zeolite

Smouldering is a low-energy, low-cost, effective treatment technology for sludge with high moisture. However, combustible gas and pollution in the flue gas limit the low-cost operation. This work proposes a novel method to in-situ reduce gas emissions (CO, NO, VOCs) and absorb heavy metals by regulating inert media with low-cost natural zeolite in self-sustained smouldering of sludge, and the effect of natural zeolite blending ratio on the performance is deeply investigated by fixed-bed and smouldering experiments. Fixed-bed experiments show that adding natural zeolite contributes to the sludge reaction owning to the confined catalysis with porous structure, as observed by the more rapid oxygen consumption, lower CO/NO concentrations. Moreover, smouldering experiments demonstrate that the endothermic dehydroxylation and dehydroxylation processes of the pure natural zeolite decreases the smouldering temperature and the propagation velocity, reduces the pyrolysis layer, but adding natural zeolite significantly reduces the concentrations of CO/NO/VOCs in the flue gas. Furthermore, higher heavy element content in the post-reaction natural zeolite is observed, indicating that the inorganic minerals in natural zeolite can effectively absorb the heavy elements. Taking reaction intensity, CO/NO/VOCs reduction and heavy element absorption into account, adding a small amount of natural zeolite (Sand: Natural-zeolite = 2.90:0.10) may be reasonable with obtaining good performance. Finally, the organic components in condensable liquids of the smouldering flue gas are deeply analyzed, and the main components is 36.7% for amides and 23.41% for nitrogen-containing heterocyclic compounds. This work can provide a possible pathway and useful information for the low-cost application of the sludge smouldring technology.

Effects of ZSM-5 zeolite on pyrolysis of polystyrene: from stabilizing to catalyzing.

Nonisothermal pyrolysis measurements of polystyrene (PS)/ZSM-5 zeolite hybrids are conducted in N2 and thermogravimetric results have been kinetically analyzed with different isoconversional methods. Experimental results show that the addition of 5 and 10 wt.% ZSM-5 zeolite has increased the initial pyrolysis temperature of PS while the addition of 20 and 30 wt.% ZSM-5 zeolite can significantly decrease the initial pyrolysis temperature of PS. Elevated activation energy is resulted by adding low zeolite amount whereas reduced activation energy is obtained by adding high ZSM-5 amounts. The effect of zeolite ZSM-5 on PS pyrolysis can thus be observed to transfer from stabilizing to catalyzing. Furthermore, the pyrolysis mechanism functions of PS/zeolite hybrids are determined by integrating the master plots method with a new compensation effect method, and the most appropriate reaction models are found to be F0.92, F0.85, F0.56 and A1.32 for describing the pyrolysis of the PS/ZSM-5 hybrids with a zeolite loading of 5, 10, 20 and 30 wt.%, respectively. With the kinetic parameters thus available, the temperature-dependent mass conversion curves have been recast, leading to satisfactory simulations for PS/ZSM-5 hybrids.

Development of a Low-Shrinkage-Lightweight Engineered Cementitious Composite Based on Heavily Doped Zeolites

In recent years, there has been a growing utilization of lightweight engineered cementitious composites (LECC) for the reinforcement and restoration of contemporary building structures. This study focuses on the incorporation of zeolite, serving as an internal reservoir for moisture maintenance, and examines its impact on various performance indicators, including apparent density, compressive strength, tensile strength, and autogenous shrinkage. Additionally, the influence of zeolite on the tensile and ductile properties of LECC is elucidated with the aid of scanning electron microscopy (SEM). The findings reveal that the addition of zeolite enables the preservation of excellent mechanical properties of LECC while further reducing its density. Notably, the introduction of a substantial amount of zeolite leads to a decrease in matrix density, average crack width, and ultimate tensile strain. The ultimate tensile strain exceeds 8% to reach 8.1%, while the decrease in compressive and tensile strengths is marginal. Zeolite’s internal curing capability facilitates the complete hydration of unhydrated cement, concurrently alleviating the autogenous shrinkage of LECC. Consequently, the durability and reliability of the material are enhanced. The ability of zeolite, with its porous framework structure, to significantly improve the ultimate tensile strain of the matrix can be attributed to the amplified occurrence of active defects and a shift in the pull-out mode of PE fibers from “pull-out” to “pull-through”. This study presents a promising alternative material in the field of engineering, holding potential for diverse building and infrastructure projects, as it enhances their durability and reliability.

Zeolite addition in microalgae Chlorella sp. for treatment of bacteria contaminated vinasse

AbstractChlorella pyrenoidosa has been grown in artificial vinasse digestate. The method being used is intended to gather data on kinetic parameters that govern the performance of C. pyrenoidosa cultivated in a medium containing bacterial components. This condition was developed by introducing 1000 μL of Bacillus cereus to the medium (5 ppm of vinasse: 15 ppm of NaHCO3 = 3:2), which was subsequently mixed with C. pyrenoidosa culture at a 1:1 v/v ratio. The cultivation was carried out in batch mode for 15 days. The photosynthesis process of C. pyrenoidosa was conducted in 14 h and supported by 2 mL L−1 Guillard, which was given every 5 days. The study additionally investigated how different amounts of Zeolite (30, 60, and 90 gL−1) affected the kinetic parameters of microalgae grown in artificial vinasse digestate. This study demonstrated that the utilization of artificial vinasse digestate as a growing medium for C. pyrenoidosa resulted in growth limitation symptoms of microalgae, as a consequence of unfavorable interaction between C. pyrenoidosa and bacteria that already existed in the medium. This is indicated by low values of growth kinetics parameters, including specific growth rate (0.0259 d−1) and biomass productivity (0.51774 gL−1d−1) as compared to the reactor without bacteria in the medium. Therefore, adding a certain quantity of Zeolite to the reactor is a promising alternative for mitigating the negative effects of bacterial presence. With the addition of 90 g L−1 of Zeolite to the reactor, the specific growth rate of C. pyrenoidosa increases by 71%, indicating an appropriate growth. In addition, the total yield of PHB formation and the Melanoidin degradation efficacy of this reactor improved by 70% and 98%, respectively.

Characterization and application of natural Moroccan material for methyl violet 2B dye removal from aqueous solution.

In this paper, a natural Moroccan material from the Nador area in the north east of Morocco was studied as an adsorbent to remove methyl violet 2B dye from aqueous solutions. This material has never been studied before in this region, and it will be used in its raw state. It was collected and characterized by X-ray diffraction, FTIR spectroscopy, scanning electron microscopy, X-ray fluorescence, thermal analysis, N2 gas adsorption-desorption, pHPZC, and Brunauer-Emmett-Teller (BET). The studies are realized with a 500-µm grain size and 182m2/g BET surface area. XRD showed the presence of significant peaks belonging to natural zeolite type clinoptilolite-Ca and minor phases. Several parameters were studied such as contact time, adsorbent mass, initial dye concentration, initial pH solution, the particle size of the material, and temperature. Out of the three isotherm models investigated after 60min of contact time in the experiments, the Langmuir model gave the best fit to the experimental data (R2 = 0.99). The results of kinetic and thermodynamic studies revealed that the adsorption process obeyed pseudo-second-order, spontaneous (ΔG° < 0), endothermic (ΔS° > 0). The adsorption of methyl violet 2B dye is chemisorptions and physisorption. The maximum theoretical adsorption capacity was 30.30mg·g-1 at 23°C for a particle diameter of 500µm. The desorption study shows that the material can be desorbed using solvents. The reuse study indicates that the same amount of natural zeolite can be used several times which makes the process efficient and sustainable. The obtained results indicate that the country of Morocco has natural zeolite among its resources and that it can be used as an efficient adsorbent for the removal of dyes.

The Effect of Zeolite (Clinoptilolite) as a Feed Additive and Filter Material for Freshwater Aquariums

Ammonia, which occurs as a natural result of aquaculture in production facilities, has a negative effect on the quality of aquaculture water and aquatic organisms. In this study, it was aimed to determine the effect of zeolite in fish feed and in water, which has the ability to adsorb ammonium, on ammonia removal. In the study, 12 different experimental groups were organized by creating 0, 2, and 10% ratios for fish feed (G1-G3), groups that zeolite only in water (G4, G5), and combinations (zeolite and/or in water/in feed) of 0, 7, and 20 g/L amounts to water (G6-G12). When NH3 and TAN data of G1-G3 were examined, it was determined that although there was no statistical difference, it decreased proportionally with the increase in the amount of zeolite in the feed. The difference between water temperature, dissolved oxygen, pH, NH3 and TAN values in G4 and G5 groups was found to be insignificant. The dissolved oxygen, pH, NH3 and TAN values between the groups (G6-G12) were statistically different. As a result, it was determined that 10% addition of zeolite into the feed decreased the TAN values by 37%, and the addition of 10% into the feed and 20 g/L into the water decreased the TAN values by 45%. When the results are evaluated from another point of view, considering the economy and ease of use, it is concluded that 2% zeolite in feed and/or 7 g/L in water can be recommended for aquatic species with high tolerance to ammonia values.

Metabentonite and metakaolin-based geopolymers/zeolites: relation between kind of clay, calcination temperature and concentration of alkaline activator

In this paper, the composition and properties of two different activated calcinated clays were investigated under selected curing conditions. The tendency of metabentonite and metakaoline to form geopolymers and zeolites was investigated by FTIR spectroscopy, TGA and DSC techniques, PXRD, HT-PXRD, SEM, and BET-N2 adsorption analyses. The selection of the optimal sample compositions was done on a basis of preliminary results obtained from bentonite and kaolin clays activated at calcination temperatures (700, 750, 800 °C) with a holding time of 3 h in a combination with different NaOH concentrations (5, 10, 20 mass%). In a more detailed examination, the samples calcined at a temperature of 800 °C with different NaOH concentrations were studied. For metakaolin-based samples, dominant geopolymer formation was achieved using 5 mass% NaOH. The zeolite amount increased concomitantly with the concentration of the alkali activator, whereas zeolite A and zeolite P were determined as the predominant phases. For metabentonite-based samples, 10 mass% NaOH concentration was found to be optimal by the means of geopolymer formation. At higher alkaline activator concentrations, the presence of zeolitic phases faujasite and gobbinsite was confirmed. However, the determined degree of crystallinity was significantly lower than in the corresponding activated metakaolin samples. With a gradual increase in NaOH concentration, the specific surface area of the metabentonite-based samples increased reaching a value of 218.95 m2 g−1 promising for adsorption applications. The opposite effect was observed for the metakaolin-based samples, and this result is caused by the increased formation of zeolite phases and corresponding changes in their channel dimensions.

Synthesis, structural analysis, DFT and molecular docking studies of N-(6-(((E)-4-methoxybenzylidene)amino)hexyl)-1-(4-methoxyphenyl) methanimine and its hydrate as a possible 2019-nCoV protease inhibitor

N-(6-(((E)-4-methoxybenzylidene) amino) hexyl)-1-(4-methoxyphenyl) methanimine (1) and its hydrate (2) were synthesized by refluxing hexamethylene diamine and anisaldehyde in presence of catalytic amount of H-Beta zeolite in solvent methanol. Resulting imines were characterized by spectroscopic analysis augmented by Single crystal X-ray diffraction. Both compounds crystalize in monoclinic crystal systems with different point groups P 21 and C 2/c. Pair wise aromatic π-CH and CH- π interactions with distance 2.887 and 2.786 Ao and iminic CH- π interactions with the distance of 2.73 Ao are mainly responsible for extending the structure along 3 dimensions. However, hydrated structure exhibited an addition hydrogen bonding with H of water molecules with the distance of 2.030 Ao , also methoxy O is involved in hydrogen bonding interaction with CH with the distance of 2.641 Ao. Probable contact points and most important crystal packing contributions were determined by employing Hirshfeld surface analysis. H…H and C…H contacts are the most important contributors in the Hirshfeld Surface. Electronic and structural characteristics of both compounds has been calculated using B3LYP/6-311G (d,p) theory. In addition, FMO and MEPS analyses were also accomplished for optimized structures. Molecular Docking studies of compound 1 and 2 were carried out with protease enzyme of 2019-nCoV (PDB-ID 7BRO), monohydrate(2) was involved in more favourable interactions hence accounting for greater binding energy (-7.98 kcal/mol) and inhibition constant (12.96 mM) than compound 1 exhibiting inhibition constant of 39.25 mM and binding energy of -6.23 kcal/mol.

Analysis of critical water flow and solute transport parameters in different soils mixed with a synthetic zeolite

The addition of natural or synthetic zeolites alters a soil’s chemical, physical and biological properties. Due to the existence of a complex internal structure, zeolites have the potential to modify soil structure and texture with a direct impact on soil hydrological properties, introducing the possibility of controlling soil and groundwater pollution as well as irrigation management practices.In the present study, a series of laboratory tests were conducted on soil samples mixed with zeolite to investigate the possible changes in hydraulic and solute transport properties and related parameters. To determine the above properties, four soils of different textures were selected and two distinct groups of experiments were conducted on disturbed (i.e., repacked) soil samples by adding known amounts of zeolite (i.e., 1, 2, 5 and 10%; w/w). Solute transport properties were determined on one group of soil samples using the so-called Kachanoski approach to monitor miscible flow experiments. Soil hydraulic properties were determined on the second group of soil samples by measuring soil water retention curves (SWRCs) and saturated hydraulic conductivity (Ks). In general, we observed significant changes in the measured properties with zeolite percentages of 5% and 10%. However, some changes were also evident at 1% and 2% of zeolite addition. These observed differences may be mainly ascribed to changes in the soil’s pore size distribution due to the addition of a finer fraction (i.e., zeolite) to soils. This fraction reduces macropores (that are occluded in proportion to their amount) and thus enhances the formation of meso- and micropore regions.