Artificial Zeolite Research Articles

Zirconium-loaded zeolite composites for selective sorption of 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP) from water: Performance and mechanism

Three zirconium-loaded zeolite (Zr-Z) composites—namely, Zr4+-Z, ZrO2-Z, and ZrMo2O8-Z—were prepared by co-precipitation of Zr4+, ZrO2, and ZrMo2O8, respectively, with artificial zeolite, and these composites were used for the efficient removal of a representative phosphonate, i.e., 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP). The adsorption efficiency of the three composites for HEDP at an initial concentration of 2 mg/L was more than double that of artificial zeolite. Pseudo-second-order kinetics could fit the adsorption process of the three composites well. The heterogeneous adsorption by Zr4+-Z, ZrO2-Z, and ZrMo2O8-Z was determined by using the Sips model. And the theoretical maximum HEDP-adsorption capacities of Zr4+-Z, ZrO2-Z and ZrMo2O8-Z were 3.52 mg P/g, 3.38 mg P/g and 3.77 mg P/g, respectively, at 308 K. At pH 4–9, the three Zr-Z composites could achieve efficient and stable HEDP adsorption. Among Co-existing ions (Cl−, HCO3−, NO3−, SO42−, Ca2+, Mg2+), 50 mM HCO3− hindered adsorption due to its competition with HEDP. The characterization results show that the adsorption mechanism involved hydrogen bonds, electrostatic attraction, and ligand exchange. In addition, the reusability and column adsorption performance of the Zr-Z composites were explored for the efficient removal of the organic phosphonate HEDP from wastewater in practical applications.

Adsorption of Fluoride from Aqueous Solution by Zirconium-Modified Artificial Zeolites: Kinetics, Thermodynamics and Mechanism

Artificial zeolites (AZ) and AZ modified with zirconium cation (AZZ) were fabricated in this work. AZ and AZZ, which were characterized by SEM and XRD, showed that AZZ was the composite of AZ and ZrO2. The adsorption kinetics and isotherms of AZ and AZZ towards fluoride removal in water were consistent with the Langmuir and pseudo-second-order models, respectively. AZZ had better fluoride adsorption capacity than AZ. The maximal adsorption capacity of fluoride onto AZZ reached up to 128.2 mg/g. Moreover, the thermodynamic studies illustrated that the adsorption procedure was spontaneous and endothermic. The effect of solution pH on AZZ fluoride adsorption was also investigated, and the results showed that the more acidic the fluoride solution, the better the fluoride adsorption capacity. After five cycles of regeneration, the adsorption capacity of AZZ was maintained at 78 %. Based on zeta potential measurements, this work proposed that the electrostatic attraction between AZZ and fluoride ions (F-) should be the mechanism for F- adsorption onto AZZ in water.

Application of titanium suboxide electrode in electrochemical polarity reversal descaling-filtration crystallization coupling system

In the electrochemical (EC) polarity reversal descaling, frequent polarity reversal shortens the electrode's service life, and the large amount of scale peeled off from the cathode can impact the quality of the effluent. To overcome these challenges, this study proposes a periodic polarity reversal electrochemical descaling process coupled with a filtration crystallization (FC) system. Both the anode and cathode utilize titanium suboxide (Ti4O7) electrodes to remove hardness ions from circulating cooling water (CCW). The unique oxygen vacancy structure of Ti4O7 electrodes allows for an extended electrode lifespan which is 2.5 times electrode lifespan under the constant current supply mode through periodic polarity reversal. In comparison to mesh electrodes, plate electrodes exhibit higher water treatment efficiency and scale detachment ability. The optimal descaling efficiency of 17–20 % was achieved at a current density of 8 mA·cm−2 and a flow rate of 2.7 L·h−1. After operating for 420 min and then reversing the polarity, the scale detachment reaches 90.2 % within 20 min of polarity reversal. By coupling the electrochemical process with a filtration crystallization system filled with artificial zeolites, the overall hardness removal of the system can be increased to 25.5 %–27.3 %. Furthermore, the system maintains good treatment performance even after 20 cycles. This study innovatively applies the Ti4O7 electrodes to electrochemical polarity reversal descaling, providing a reference for the development of related descaling technologies.

Combination of artificial zeolite and microbial fertilizer to improve mining soils in an arid area of Inner Mongolia, China

Combination of artificial zeolite and microbial fertilizer to improve mining soils in an arid area of Inner Mongolia, China

Pengolahan Air Sadah Menggunakan Zeolit Buatan Dari Batu Apung Lampung Dan Daun Kerai Payung

This research was conducted to determine the composition and crystal structure of the artificial zeolite produced, as well as the ability of artificial zeolite to reduce calcium and magnesium content in hard water. The zeolite was prepared using the hydrothermal method by mixing sodium silicate from Lampung pumice silica, sodium aluminate from aluminum can waste and charcoal from sunshade umbrellas. The artificial zeolite products were characterized using XRF, XRD, UV-Vis spectrophotometric and ICP-EOS. The results showed that the composition of the artificial zeolite was aluminum, silica, phosphorus, potassium, calcium, titanium, vanadium, chromium, manganum and ferum. The crystal structure of the optimum sample from the UV-Vis spectrophotometric characterization obtained the crystal structure of a natural zeolite type, namely Chabazite. And the artificial zeolite which was tested for adsorption on hard water could reduce the calcium content by 36.57% but could not reduce the magnesium content.

Regulating ordered structure and multi-functions of zeolite aerogels for solar steam generation and heavy metal ion adsorption

The interfacial solar steam generation (ISSG) is considered to be a promising technology to alleviate the water crisis. However, the salt accumulation on the solar evaporators and the heavy metal pollution in water hinder the commercial potential and practical application of the evaporators. Herein, a solar evaporator with high salt resistance and efficient heavy metal wastewater treatment is designed using commercial artificial zeolite as matrix, modified zeolite (MZ), cellulose acetate (CA), and carbon nanotubes (CNTs), named as MZPC@CNTs. The applicability of the developed MZPC@CNTs in water evaporation, seawater desalination, heavy metal wastewater treatment, and water purification of organic pollutants is studied systematically. Through the regulation of the ordered structure and multiple functions, the obtained MZPC@CNTs based aerogel shows an evaporation rate of 1.72 kg m-2 h−1 with a corresponding efficiency of 95.33% under 1 sun radiation. In addition, the MZPC @CNTs aerogel also exhibits excellent ion desalination performance and excellent salt resistance towards the purification of heavy metal-contaminated wastewater. This solar evaporator has the advantages of simple preparation, low cost, and stable desalination performance, and reveals great potential in alleviating the shortage of global freshwater resources.

Influence of Sodium Silicate, Sodium Aluminate, and Filicium Decipiens Charcoal on The Conductivity of Artificial Zeolite

Fly ash-bottom ash of coal is a solid waste in many industries and electric power plants. One method to reduce that solid waste is by using it to produce artificial zeolite. The Filicium decipiens charcoal was added into artificial zeolite to increase its performance to adsorb water pollutants. The pumice stone is also used in this work as a source of silica. The manufacture of artificial zeolite was carried out by the hydrothermal method by optimizing the composition of sodium silicate from Lampung pumice silica, sodium aluminate from aluminum scrap, and charcoal of Filicium decipiens. From the characterization of the LCR meter, the optimum artificial zeolite obtains the conductivity value from 9.14×10-6 (S/cm) to 6.09×10-6 (S/cm), confirming that artificial zeolite is a semiconductor material. The highest conductivity of artificial zeolite will increase its performance as a catalyst and absorbent. The composition of the artificial zeolite after XRF characterization was aluminum, silica, phosphorus, potassium, calcium, titanium, vanadium, chromium, Mangan, and ferrite. From the XRD characterization result obtained, the dominant phase is Zeolite-A. SEM-EDX characterization results obtained a spherical and cylindrical microstructure of artificial.

N, P, K recovery from hydrolysed urine by Na-chabazite adsorption integrated with ammonia stripping and (K-)struvite precipitation.

This study investigated the recovery of K+ along with NH4+-N and PO43--P from hydrolyzed urine by technical integration. The K adsorption capacities of biochar, clinoptilolite, artificial zeolite and chabazite were firstly compared. Due to the high K recovery efficiency and additional P recovery capacity, Na-chabazite was selected as the adsorbent in this study. Its kinetics and isotherm analysis indicated that the high molarity of NH4+-N seriously hindered the K adsorption onto Na-chabazite in synthetic hydrolyzed urine (SHU). However, this competition between NH4+ and K+ got diminished when their molarity is the same, i.e. in the SHU after ammonia stripping (ASSHU). Based on this key finding, Na-chabazite adsorption was integrated with ammonia stripping and struvite precipitation under different configurations. Simultaneous ammonia stripping was inadequate to diminish the competitive effect of NH4+ on K+ adsorption. Depending on the demand for fertilizer, two sequential configurations were recommended, respectively.

Investigation of disused artificial zeolite on the properties of metakaolin-based geopolymer

Artificial zeolite deactivated after repeated utilization and the properties compromised formed disused zeolite. In the past, disused artificial zeolite landfilled after incineration and results in environmental pollution and resource waste. This work synthesized a new type of a new metakaolin-based geopolymer prepared by using disused artificial zeolite and metakaolin. The influence of disused artificial zeolite on the performance and pore structure of the final products was investigated. The bulk density and compressive strength of the samples were approximate 457 kg/m3 and 1.3 MPa, respectively. Moreover, disused artificial zeolite has good mesoporosity and strong foaming performance. The incorporation of disused artificial zeolite generated more pores with smaller diameters and pronounced pore grading, adjust the pore structure of the samples, forming multiscale pore structured structures. This study described one application method of disused artificial zeolite in geopolymers, synthesized a new metakaolin-based geopolymer, which is significant for exploring the potential utilization value of disused artificial zeolite.

Clinoptilolita natural mexicana para la deshidratación de etanol: adsorción - regeneración y escalamiento de los parámetros experimentales a nivel planta piloto

The separation of ethanol-water azeotropic mixtures by adsorption-regeneration process using a natural Mexican Clinoptilolite has been studied. For this, the equilibrium parameters were determined from experimental data obtained at the laboratory level, which were used as a starting point for the calculation of a column at Pilot Plant scale. First, on the basis of experimental data from three different sizes of natural Mexican clinoptilolite (1-2, 3 and 5 mm) and two artificial ones with 1 and 3 mm, and from the application of standard fitting techniques: Langmuir, Freundlich and linear model parameters are calculated and compared. Then, the breakthrough curves (BTC) are determined for each zeolite in a packed bed, yielding that the adsorption and capability of natural clinoptilolite is similar to those presented by artificial zeolites. The regeneration method PSA was evaluated for each zeolite. Finally, according to the experimental parameters set, a calculation of a pilot-plant scale column is included for a validation and the results are compared with the results obtained at the laboratory scale, which presented a similar behavior. We can conclude that the use of Mexican zeolite in the ethanol dehydration process could be a good low-cost alternative that is easy to apply

Simple Fabrication of PEG Modified W<sub>18</sub>O<sub>49</sub> for Enhanced Adsorption Performance towards Methylene Blue

The W18O49 nanoparticles were synthesized by solvothermal method with tungsten chloride as raw material and n-propanol as solvent. Polyethylene glycol 400 (PEG-400) was modified for W18O49 nanoparticles (W18O49@PEG). The structure and morphology of W18O49 and W18O49@PEG were characterized by XRD and SEM. Methylene blue aqueous solution was used as wastewater adsorption model. And the comparative experiments with other absorbent materials, such as artificial zeolite and activated carbon were also conducted. The results revealed that after modifying by PEG-400, W18O49 has a better adsorption performance than other materials due to its large specific surface area and high surface energy. Finally adsorption circulation experiment was performed，the results indicate that the W18O49@PEG nanoparticles show great potential in the treatment of colored wastewater.

Effect of modified fly ash on environmental safety of two soils contaminated with cadmium and lead

In this study, a low-temperature roasting and hydrothermal methods were used to modify the fly ash resulting in two new types of adsorption materials - modified fly ash (MFA) and artificial zeolite (ZE). These modified fly ashes, as well as a natural zeolite (ZO) were applied to two types of contaminated soils to explore their effects and mechanisms on the behavior of Cd and Pb through leaching column experiments. The bioavailable of Pb, Cd, pH, dissolved organic carbon (DOC), organic matter, as well as the microbial community changings were detected. The results showed that, 2% ZE has a significant stabilizing effect on Cd and the bioavailable fraction contents in Guanzhong (GZ) and Hunan (HN) soils decreased by 40.5% and 53.2%, respectively. However, for Pb, the 2% MFA showed a better result than that of ZE and ZO; the contents of bioavailable Pb in HN and GZ decreased by 48.3% and 30%, respectively. Furthermore, based on the Illumina NovaSep sequencing platform, 18 soil samples of GZ and HN were sequenced for microbial communities. As compared to the control blank(CK) treatment, the abundance of soil microbial communities was significantly improved in the amended soils.

Brønsted acid-driven conversion of glucose to xylose, arabinose and formic acid via selective C–C cleavage

The efficient production of xylose and arabinose from glucose, is significant but technologically challenging. Herein, the conversion of glucose to pentose (xylose and arabinose) and formic acid was realized using non-toxic artificial zeolite and green solvent of γ-butyrolactone-H2O. The selective conversion of glucose to 5-hydroxymethylfurfural, pentose and furfural could be regulated by controlling Brønsted acid strength. The weak Brønsted acid could promote the formation of pentose, while strong Brønsted acid could lead to the formation of HMF and further degradation of pentose to furfural. The mechanism was investigated spectroscopically to add fundamental insights to the selective C1-C2 bond cleavage. The solvent of γ-butyrolactone-H2O reduced apparent activation energy by promoting the formation of active d-fructofuranose. The favorable yield reached to 54.3 % pentose and 54.7 % formic acid from glucose, while 95.6 % pentose and 96.8 % formic acid from fructose at 453 K for 1.5 h. This strategy offered a new utilization way of glucose in expanding the varieties of platform chemicals.

Removal of U(VI) from aqueous solution using AO-artificial zeolite

Amidoxime (AO) based adsorbents have been proposed as low cost and efficient adsorbent for U(VI). Herein, we present a simple strategy for preparing AO modified artificial zeolite. The composition and morphology of the materials have been confirmed via XRD, FT-IR, TGA and SEM. The AO-artificial zeolite was synthesised as an efficient adsorbent for adsorbing U(VI). The critical factors affecting U(VI) adsorption from aqueous solution were exploited, such as pH, contact time, temperature and adsorbent dosage. This study reveals AO-artificial zeolite, along with a low-cost, environmentally friendly and facile synthesis, can be regarded as a promising material for uranium-containing wastewater treatment.

Enhanced adsorption of methylene blue from textile wastewater by using natural and artificial zeolite.

This study investigated the adsorption of methylene blue with natural and artificial zeolite. The effect of pH, contact time, initial concentration and adsorbent dose on adsorption was also investigated. An artificial dye was prepared. Adsorption removal efficiency was low at pH = 2, 3 and 4 but it was quite high at pH = 7. It was determined that the contact time reaches equilibrium within 60 minutes in the adsorption of methylene blue with natural and artificial zeolite. The initial dyestuff concentration for both adsorbents was 5 mg/L. For the removal of methylene blue, a 0.5 g natural and artificial zeolite dosage was sufficient. In order to express the adsorption of natural and artificial zeolite on methylene blue, Langmuir, Freundlich, Temkin and Dubinin-Radushkevich (D-R) isotherm models were examined. In the isotherm study, both natural and artificial zeolite adapted to the Langmuir isotherm model. Langmuir correlation coefficient was 0.998 for artificial zeolite and 0.993 for natural zeolite. Both adsorbent materials best fit into the pseudo-second kinetic model with similar correlation coefficient values of 0.999.

Characterization; formulation and application of Natural Nano zeolitic materials from Kenya as Smart Delivery Systems for fertilizers and pesticides

This study aimed at using natural zeolitic materials sampled form different places and characterized as nano porous smart delivery systems for storage and controlled release of fertilizer and pesticide molecules. XRD characterization of sample ZT-GA-01 showed that it was zeolite A artificial, abbreviated as Linde Type A (LTA), sample EL-GA-06 was Phillipsite natural zeolites. IR Spectroscopy for ZT-GA-01 and EB-GA-02 showed similar peaks between 3420 – 3480 cm-1, 2350 – 2360 cm-1 and 1630 – 1660 cm-1 indicating H-O-H stretching and bending, while 440 – 670 cm-1 representing Si-O-Si bending for internal tetrahedral. Besides comparable EDX characterized silica to alumina composition of sample EB-GA-02 and the artificial zeolite A applied as the standard, determined as 37.4 % to 18.8 % and 43.6 % to 56.4 % respectfully. Physical properties of samples ZT-GA-01 and EB-GA-02 in terms of BET surface area, BJH pore volume and pore sizes were obtained as; 0.6716 m2/g, 0.002333 cm3/g, 151.519 Å and 0.7099 m2/g, 0.006767 cm3/g, 389.846 Å respectively. Urea loaded samples EB-GA-02 indicated a 39.844 % reduction in pore sizes after successful loading of urea fertilizer into the nano-spaces, while pesticide loading indicated a reduction in pore volumes and pore sizes by 19.15 % and 32.74 % respectively. The simulated release shoed about 82.8 % of stacked urea fertilizer discharged in water and 74.2 % loaded urea released in soil, while 34.4 % and 40.1 % lambda cyhalothrin pesticide amounts were released by pesticide loaded zeolitic sample EB-GA-02 in water and soil respectively. Application of zeolitic sample EB-GA-02 as smart delivery systems demonstrated a sustained slow release of both urea and Lambda cyhalothrin pesticide on tomato and spinach growing and monitoring experiments for the 60 days’ period. In conclusion, our study showed that there exist zeolites and zeolitic materials in some selected parts in Kenya. As well, identified zeolitic sample EB-GA-02 can be used to successfully store agrochemical molecules and significantly delay their release in soil hence applied as nanozeolitic smart delivery systems.

Removal of Cr(VI) from wastewater by artificial zeolite spheres loaded with nano Fe–Al bimetallic oxide in constructed wetland

In order to solve the problems of poor adsorption capacity and low stability in treating heavy metal wastewater with traditional constructed wetland (CW) fillers, a new type of filler, artificial zeolite spheres loaded with nano Fe–Al bimetallic oxide (hereinafter referred to as composite zeolite spheres), was prepared for Cr(VI) removal from wastewater. The results indicated that nano Fe–Al bimetallic oxide was an effective material for Cr(VI) removal with the maximal removal efficiency of 84.9% at initial Cr(VI) concentration of 20 mg/L (pH = 3). The micro-reactor experiment further verified that composite zeolite spheres had better removal performance on Cr(VI) than traditional filler. Fourier-transform infrared (FT-IR), X-ray diffractometry (XRD) and X-Ray photoemission spectroscopy (XPS) results demonstrated that –OH groups reduced Cr(VI) to Cr(III), and then the Cr(III) was removed by forming CrxFe1-x(OH)3 precipitation with Fe(III) or formed Cr(OH)3 precipitation with Al–OH through the ion exchange. This study provided an effective approach for treating Cr(VI) wastewater by using a new composite zeolite in constructed wetlands (CWs).

The role of the crystallo-chemical factor in the evaluation and improvement of the nanomodification efficiency of mortar and concrete

The article presents a new approach to the control of the processes of structure formation of binder systems, taking into account the achievements of nanotechnologies. The possibilities of managing the structure of the material at the nanoscale and the micro-level by introducing primary nanoscale additives or forming nanoscale objects in the bulk of the material are considered. The peculiarities of contact zone formation and microstructure of artificial stone based on nanomodified Portland cement and alkaline binder systems are investigated. The role of the crystallo-chemical factor and its influence on the strength formation of all levels of concrete structure are shown. It is proved that when using micro silica modifying additives, their efficiency at the micro level is higher than at the meso- and macro-levels. At the same time, the modification of the binding systems by artificial zeolites provides a more pronounced effect in concrete at the macro-level – due to the crystallo-chemical similarity of additives, products of hydration and minerals of the aggregate. Taking into account the crystal-chemical similarity of the new formation opens new possibilities for the choice of nano additives, considering not only the principle and nature of their action at the level of nanoscale and microstructure, but also the influence on the peculiarities of the formation of the contact zone at the meso- and macro-levels, which will have a decisive influence not only on the strength, but also on the special properties of concrete.

Adsorption of the anionic dye methyl orange on used artificial zeolites: kinetic study and modeling of experimental data.

The adsorption of methyl orange (MO) dye by artificial zeolites beads, used previously in the removal of heavy metal through the ionic exchange process, has been studied. The effect of several parameters such as temperature, MO concentration, and zeolite mass on MO adsorption was tested in order to determinate optimal conditions. All results have shown that the adsorption process was influenced by the studied parameters. The kinetic data concerning the study of temperature effect was modeled through pseudo-first-order and pseudo-second-order to determinate the adsorption mechanism. Thermodynamic parameters were calculated using the Van’t Hoff equation. Also, they have shown that the studied process has an endothermic, stable and spontaneous nature.

Development of synthetic zeolites from bio-slag for cesium adsorption: Kinetic, isotherm and thermodynamic studies

This study reported a novel synthetic zeolite based adsorbent developed from the municipal wastewater sludge molten slag (bio-slag) through the hydrothermal modification process for removal of cesium (Cs) from simulated wastewater. The artificial zeolites were produced from the raw bio-slag which was identified by the several physicochemical experimental procedures such as the surface area analysis (the BET technique), the FESEM, the XRF and the XRD. The Cs adsorption process of modified bio-slag was exmined by the linear pseudo-first order, pseudo-second order and intra-particles diffusion models whilst the second order kinetic model confirmed a better agreement with the correlation coefficient, R2 = 0.999-1.000 for 20-400 mg/L Cs solution. The Langmuir, Freundlich and the Temkin isotherm model were investigated using the adsorption isotherm data. A satisfactory correlation coefficient value (R2= >0.980) proved that the isotherm parameters were perfectly fitted to the Langmuir and Freundlich model and the highest Cs adsorption ability of modified bio-slag were 51.02, 51.02 and 49.51 mg/g at 288, 298 and 308 K, respectively. The better agreement of adsorption data with the second order kinetic model and the Langmuir model proved the adsorption mechanism was controlled by the chemical reaction (ion-exchange). Thermodynamic studies under the different temperatures proved that the adsorption reaction was endothermic (ΔH =20.53 kJ/mol) and ΔS = 0.021 kJ/mol/K) and non-spontaneous (ΔG>0). Moreover, the modified bio-slag effectively removed Cs even in the co-existence of Na+ and K+ as competitive ions at their wide range of concentrations (upto 300 mM) although the higher concentration slightly affected the Cs adsorption.