Surface Modification Of Zeolite Research Articles

Urinary biomonitoring of fuel ether oxygenates using a needle trap device packed with a novel molecularly imprinted polymer surface modified Zeolite Y

This study introduces an innovative needle trap device (NTD) featuring a molecularly imprinted polymer (MIP) surface-modified Zeolite Y. The developed NTD was integrated with gas chromatography-flame ionization detector (GC-FID) and employed for analysis of fuel ether oxygenates (methyl tert‑butyl ether, MTBE, ethyl tert‑butyl ether, ETBE, and tert‑butyl formate, TBF) in urine samples. To optimize the key experimental variables including extraction temperature, extraction time, salt concentration, and stirring speed, a central composite design-response surface methodology (CCD-RSM) was employed. The optimal values for extraction in the study were found to be 51.2 °C extraction temperature, 46.2 min extraction time, 27 % salt concentration, and 620 rpm stirring speed. Under the optimized conditions, the calibration curves demonstrated excellent linearity within the range of 0.1–100 μg L−1, with correlation coefficients (R2) exceeding 0.99. The limits of detection (LODs) for MTBE, ETBE, and TBF were obtained 0.06, 0.08, and 0.09 μg L−1, respectively. Moreover, the limits of quantification (LOQs) for MTBE, ETBE, and TBF were obtained 0.18, 0.24, and 0.27 μg L−1, respectively. The enrichment factor was also found to be in the range of 98–129.The NTD-GC-FID procedure demonstrated a high extraction efficiency, making it a promising tool for urinary biomonitoring of fuel ether oxygenates with improved sensitivity and selectivity compared to current methods.

Surface modification of zeolite by cationic surfactant and the application on adsorptive removal of azo dye Ponceau 4R

The zeolite Permutit (Per) with the cubic crystal, 1.66 of the SiO2/Al2O3 ratio, 44.81 m2.g−1 of the specific surface area, 1.7 nm of the average pore radius, and the typical bonds of Si-OH, Si-O-Si, Si-O-Al, and O-Si-O-Si was investigated in the present study. The adsorptive removal efficiency of the azo dye PC4R was almost doubled from about 53.23% to 90.06% by Per surface modification with the cationic surfactant cetyltrimethylammonium bromide (CTAB) as an effective and high-performance adsorbent. The PC4R adsorptive removal was optimized at independent variables of pH 4, the ionic strength of 10 mM NaCl, the Per dosage of 6 mg.mL−1, and the short contact time of 15 min. Both the Langmuir and Freundlich models were reasonable to describe the PC4R adsorption isotherms on the CTAB@Per while the PC4R chemisorption kinetics were well accorded with the pseudo-second-order model. The PC4R multilayer adsorption capacity achieved an extrapolated maxima of 15.470 mg.g−1. The PC4R adsorption mechanisms were demonstrated by the FT-IR measurement to be primarily the electrostatic attractions between the CTAB and the PC4R, dipole-ion interactions, and hydrogen bondings between the PC4R molecules.

Process steam generation from low-grade waste heat in a direct- contact adsorption heat pump based on superhydrophobic surface-modified Zeolite 13X

ABSTRACT Adsorption heat pump (AdHP) is a potential technology to recover and storage low-temperature waste heat. This paper presents an experimental research on direct low-pressure process steam generation from hot water based on superhydrophobic surface-modified zeolite 13X. The measured water contact angle of the modified zeolite is larger than 150°, which restricts free water entering the pores inside the zeolite particles. Cyclic experiments are conducted for performance evaluation. High-temperature steam (205–229°C, 0.1–0.3 MPa) is generated from hot water (72°C) in the AdHP driven by dry air (130°C). The temperature of generated steam is promoted with increasing preset steam pressure, among which the temperature is raised by about 23°C at 0.3 MPa. As the boiling point of water rises simultaneously, the sensible heat demand is increased. Thus, the mass of the steam is accordingly decreased. GTL (gross temperature lift) reaches 130°C. When the preset pressure is increased, COPh (coefficient of performance for heating) and SHP (specific heat power) for direct steam generation are decreased by 36% and 39%, respectively. One feasible option to elevate these two indicators is to increase the inlet water to near boiling water to match the change in the preset pressure. However, the GTL will be decreased based on the option. Balance should be made based on the choice of design for practical application.

Removal of BTEX (Benzene, Toluene, Ethyl benzene and Xylene) from aqueous solutions using surface-modified zeolite

<p>BTEX, also known as benzene, toluene, ethyl benzene, and xylene, is a common gasoline oxygenate. The contamination of groundwater and surface water with BTEX and its primary breakdown product has drawn a lot of attention. However, surface-modified zeolite's sorption mechanisms and affinity for BTEX can be employed to potentially remove these toxins from water. Tert-butyl alcohol (TBA) was utilized to alter the morphology of the adsorbent. Based on the findings, it can be concluded that zeolites have a greater capability for removing emerging chemicals. Some of the emerging compounds' relatively large dimensions limit their natural ability to lower values. Gas chromatography was used to determine the BTEX concentration decrease range. The Yoon-Nelson and Adams-Bohart model's use of mathematical modelling to determine the efficacy of the column's adsorption. The model with the highest R2 values for characterizing equilibrium isotherm data describes equilibrium adsorption data. To gain an understanding of the shape, pore structure, and active sites, the characterisation is concentrated on quantitative analysis using XRD, qualitative analysis using FTIR, and optical study using SEM.</p>

Restraining lithium dendrite formation in all-solid-state Li-metal batteries via the surface modification of the ceramic filler

Polymer-based all-solid-state Li-metal batteries (ASSLMBs) have acquired considerable attention owing to their applicability to various systems and their enhanced safety characteristics. Hence, ASSLMBs can potentially replace flammable organic-liquid-electrolyte-based Li-ion batteries. However, owing to the interfacial instability and Li dendrite formation, ASSLMBs exhibit low capacity deprivation. To overcome this limitation, in this study, the hydrophilic nature of SSZ-13 zeolite was altered to hydrophobic using OH-functional silicone-modified polyacrylate (BYK-SILCLEAN 3700). A hydrophobic surface-modified zeolite filler (SSZ-13, MZLT) was incorporated into a polyethylene oxide (PEO) matrix, which permitted considerable Li salt adsorption and ensured the uniform distribution of MZLT in the PEO matrix. This resulted in a substantially improved ionic conductivity (σ) of the electrolyte, thereby enhancing the performance and durability of ASSLMBs. Furthermore, excellent σ (3.46 × 10−2 S cm−1 at 60 °C) was achieved through the surface modification of the filler, resulting in a Li transference number of 0.83. The Li plating–stripping results (for 1800 h of cycling at a discharge current of 100 μA cm−2) suggested satisfactory compatibility of the electrolyte with the Li metal. Scanning electron microscopy and X-ray photoelectron spectroscopy results confirmed that the growth of Li dendrites was significantly suppressed, leading to a retention rate of 98.5% after 200 cycles. Additionally, the fire retardancy was considerably improved. The findings of this study highlight the potential of composite-electrolyte-based ASSLMBs as candidates for energy storage devices.

Superhydrophobic Surface-modified zeolite to regulate the migration of nonadsorbed liquid water in an Open-loop adsorption heat pump

Superhydrophobic surface-modified zeolite 13X has been utilized to regulate nonadsorbed liquid water in an open-loop adsorption heat pump system for steam generation. The zeolite is modified by vinyltrimethoxysilane to achieve a superhydrophobic surface effect. The measured static water contact angles of the modified zeolite reached 152°. Thermogravimetric analysis results show good thermal stability at temperatures less than 400 °C. The measured adsorption capacity and adsorption heat slightly decrease for the modified zeolite. During the regeneration process dry air at 140 °C drives wet zeolite to remove adsorbed and free water. Then generation process proceeds for steam generation at a maximum of 220 °C from water at 72 °C. The mass and temperature of the steam generated from the modified zeolite bed increase compared with those of unmodified zeolite 13X. This is because of the apparent decrease in the total amount of free water, which allows the released adsorption heat to be transferred to passing water quickly for steam generation. Energy consumption during regeneration simultaneously reduces. System indicators such as the coefficient of performance for heating (COPh), specific heating power (SHP), gross temperature lift (GTL) and exergy efficiency (ηe) increase with increasing hydrophobicity of zeolite particles. The surface hydrophobicity decreases the affinity of zeolite for useless free water which cannot contribute to increasing the overall adsorption heat.

Modification of natural zeolite clinoptilolite and ITS application in the adsorption of herbicides

ABSTRACT The clinoptilolite natural zeolites (NZs) posses low herbicide adsorption capacity demanding acid-, alkali-, or salt chemical modifications that enhance its adsorption. However, this may affect the material structure and charge distribution. Alternatively, zeolites may be synthesized at a high cost and time-consuming process. Consequently, new methods, such as the hydrothermal method, for NZ modification needs to be studied. In this sense, a novel surface-modified zeolite (SMZ), using hexadecyltrimethylammonium bromide (CTAB), in acid media was produced by the hydrothermal method and applied for the adsorption of Atrazine (ATZ), Diuron (DIU) and 2,4-D. Commercial NZ and SMZ were characterized by SEM, XRD, TGA, FT-IR, AA spectroscopy, pHPZC, Zeta potential and N2-physisorption. The SMZ chosen for the adsorption experiments was the one with the highest modification yield and adsorption capacity obtained from a complete design of experiments (CTAB=0.74 ; D=12 Mesh; HCl=0.1 M; t=6 h and T=205 ºC). The adsorption experiments revealed that the SMZ adsorption capacity for the herbicide 2,4-D (qmax=9.02 mg/g) was greater than that obtained for ATZ (qmax=2.11 mg/g) and DIU (qmax=1.85 mg/g), which was explained by the presence of the hydroxyl group and by geometric characteristics of the 2,4-D. Adsorption models’ fitting showed that the adsorption of 2,4-D onto SMZ were best described by pseudo-second order kinetic (k2=0.005-0.006 g/mg.min; qe,exp=7.122-8.614 mg/g) and Langmuir isothermal model (KL=0.283-0.499 L/mg; qm=7.167-7.995 mg/g). These results indicate that the hydrothermal method is a viable alternative to enable the use of NZs for the adsorption of emerging contaminants from wastewater.

Fixed-Bed Modification of Zeolitic Tuffs and Their Application for Cr(VI) Removal.

Natural clinoptilolite tuff (CL) and chabazite-clinoptilolite tuff (CH) were modified in fixed-bed column by immobilization of hexadecyltrimethylammonium bromide (HDTMA-Br), then investigated as a sorbent for inorganic anions of Cr(VI). The proposed modification technique combined with surfactant solution batching allows minimizing the surfactant loses through foaming and crystallization and creation of stable organic coverage. The HDTMA loading depended on the mineral composition of the zeolitic tuff, the topology of its external surface, and process conditions. The maximum surface coverage was obtained by gradually dosing surfactant solution in the smallest volume of batches and corresponded up to 100% and 182% of external cation exchange capacity (ECEC) for mono and double layer coverage, respectively. In case of mono layer coverage, modification proceeds until the exhaustion of surfactant in supply solution, while in the double layer one, until equilibrium of HDTMA concentration in both zeolitic and liquid phases was established. The efficiency of Cr(VI) uptake by prepared surface modified zeolites (SMZs) increased with increasing of HDTMA loading. In the case of mono layer SMZs, the capacities of CH-HDTMA and CL-HDTMA were 10.3 and 5.4 mg/g, respectively, while in the case of double layer SMZs, the amount of Cr uptake on CH-HDTMA and CL-HDTMA were 16.8 and 15 mg/g, respectively. Ion exchange is the predominant mechanism of Cr(VI) sorption but it takes place only if modification resulted in at least partial double layer coverage. The XPS analysis reveals Cr(VI) reduction to a less-toxic Cr(III) by the electron donating N-containing groups and by reaction with Fe+2 ions on the zeolite external surface.

Preparation and characterization of magnetic sodium alginate-modified zeolite for the efficient removal of methylene blue

A magnetic sodium alginate (SA)-modified zeolite (SA/zeolite/Fe 3 O 4 ) composite was prepared using the precipitation method to remove methylene blue (MB) from wastewater. SA was deposited on the surface of zeolite through CaCl 2 cross-linked precipitation. Meanwhile, Fe 3 O 4 nanoparticles were coated by SA and precipitated onto the surface of zeolite. The carboxyl group was introduced through SA modification, which enhanced the cationic adsorption capacity of the SA/zeolite/Fe 3 O 4 composite compared with that of zeolite. Characterization analysis indicated that SA and Fe 3 O 4 were successfully loaded onto the surface of zeolite. The effect of initial pH and results of co-existing cation adsorption experiments showed that the adsorption of MB molecules on the surface of the SA/zeolite/Fe 3 O 4 composite mainly relied on electrostatic attraction. Infrared spectroscopic and X-ray photoelectron spectroscopic analyses proved that the mechanism underlying the adsorption between MB molecules and the SA/zeolite/Fe 3 O 4 composite was ion exchange. Results of the adsorption model fitting showed that the adsorption process was well described by pseudo-second-order kinetics and the Langmuir isothermal line model. Adsorption thermodynamic studies suggested that the adsorption was a spontaneous exothermic process, and Langmuir analysis revealed that the theoretical maximum adsorption capacity was 181.85 mg/g. In addition, the regeneration study indicated that the adsorption was suitable for four cycles. This study suggests that the SA/zeolite/Fe 3 O 4 composite is an ideal adsorbent for the removal of cationic dyes from an aqueous medium. • Surface-modified zeolite with SA and nano Fe 3 O 4 particles to prepare SA/zeolite/Fe 3 O 4 . • We elucidate the structural properties of SA/zeolite/Fe 3 O 4 composite. • SA/zeolite/Fe 3 O 4 adsorbed MB well by electrostatic attraction and exhibited good regenerability.

Zeolites Enhance Soil Health, Crop Productivity and Environmental Safety

In modern days, rapid urbanisation, climatic abnormalities, water scarcity and quality degradation vis-à-vis the increasing demand for food to feed the growing population necessitate a more efficient agriculture production system. In this context, farming with zeolites, hydrated naturally occurring aluminosilicates found in sedimentary rocks, which are ubiquitous and environment friendly, has attracted attention in the recent past owing to multidisciplinary benefits accrued from them in agricultural activities. The use of these minerals as soil ameliorants facilitates the improvement of soil’s physical and chemical properties as well as alleviates heavy metal toxicity. Additionally, natural and surface-modified zeolites have selectivity for major essential nutrients, including ammonium (NH4+), phosphate (PO42−), nitrate (NO3−), potassium (K+) and sulphate (SO42−), in their unique porous structure that reduces nutrient leaching. The slow-release nature of zeolites is also beneficial to avail nutrients optimally throughout crop growth. These unique characteristics of zeolites improve the fertilizer and water use efficiency and, subsequently, diminish environmental pollution by reducing nitrate leaching and the emissions of nitrous oxides and ammonia. The aforesaid characteristics significantly improve the growth, productivity and quality of versatile crops, along with maximising resource use efficiency. This literature review highlights the findings of previous studies as well as the prospects of zeolite application for achieving sustenance in agriculture without negotiating the output.

Investigation of adsorption mechanism of phosphate(V) ions on the nanostructured Na-A zeolite surface modified with ionic polyacrylamide with regard to their removal from aqueous solution

The sorption properties of Na-A-type synthetic zeolite, obtained from fly ash with regard to the phosphate(V) ions, were determined. The Na-A zeolite was prepared using hydrothermal conversion of fly ash with aqueous sodium hydroxide. The effects of solution pH and zeolite surface modification by ionic polyacrylamide (PAM) were examined. Both anionic and cationic forms of PAM were applied. The adsorption and electrokinetic data were obtained by means of spectrophotometric measurements, potentiometric titrations and zeta potential determination. It was shown that the presence of ionic polyacrylamide adsorption layers modifies the surface properties of the solid. The resulting composite material (zeolite/polymer) can be applied for effective removal of phosphate(V) ions from the liquid medium. Its regeneration possibilities are also considerable. Additionally, the use of fly ash for zeolite preparation leads to management of hazardous waste material.

Rapid removal of Sr2+, Cs+ and UO22+ from solution with surfactant and amino acid modified zeolite Y

In this study, a new and efficient sorbent material was developed by the surface modification of zeolite Y with surfactant of cetyltrimethyl ammonium bromide (CTAB) and amino acid of l -aspartic acid (Asp) for rapid removal of Sr 2+ , Cs + and UO 2 2+ in solution. The as-synthesized and modified zeolite Y were characterized by powder X-ray diffraction (XRD), scanning electron microscope (SEM), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR) and nitrogen adsorption-desorption analysis. The results showed that after first grafting the cations of CTAB on the external surface of zeolite Y crystals, negatively charged Asp was then successfully introduced onto zeolite to form the CTAB + Asp dually modified zeolite Y sorbent. The fraction of CTAB and Asp in dually modified zeolite Y is 9.6 wt % and 16.3 wt %, respectively. The sorption isotherm of UO 2 2+ , Sr 2+ and Cs + by such sorbent was better fitted by Langmuir model. The CTAB + Asp dually modified zeolite Y took 20 min to reach the maximum sorption amount, while the unmodified zeolite Y took 240 min. This encouraging result provides a new concept to design sorbent materials for rapid removal of radionuclides from contaminated water system in an emergency. • Comprehensive investigation on modified zeolite Y for radioactive cation removal. • Zeolite Y is successfully modified with CTAB and aspartic acid on the surface. • Aspartic acid modified zeolite Y has a rapid removal efficiency for nuclide cation.

Novel N-p-carboxy benzyl chitosan/poly (vinyl alcohol/functionalized zeolite mixed matrix membranes for DMFC applications

The novel N-p-carboxy benzyl chitosan (CBC)/ poly (vinyl alcohol) (PVA) based mixed matrix membranes (MMMs) filled with surface-modified zeolite have been prepared using the dissolution casting technique. The applicability of prepared MMMs for direct methanol fuel cell (DMFC) was investigated in terms of water uptake, methanol permeation, and proton conductivity by changing filler content (10−50 wt. %). The zeolite was modified by silane coupling agent, 3-mercaptopropyltrimethoxysilane (MPTMS). The resultant modified zeolite (MZ) was incorporated into CBC/PVA blend to obtain mixed matrix PEMs. The functional group, structural properties, morphological and topographical investigation of MMMs were examined using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and Scanning electron microscopy (SEM) respectively. The prepared MMMs exhibited a remarkable decrease in methanol permeability of 2.3 × 10−7 cm2/s with C-CPMZ50. The maximum value of proton conductivity of 0.0527 Scm−1, was shown by C-CMPZ10. The prepared PEMs also displayed good stability during long term operating time.

Micropollutant adsorption from water with engineered porous ceramic architectures produced by additive manufacturing and coated with natural zeolite

Treatment of waste and drinking waters has gained importance in both emerging and industrialized countries. New pharmaceutical products, industrial processes, agricultural activities are reducing water quality. To solve these problems we propose an efficient and thus economical purification method which uses commercial available natural zeolites as coating material on engineered porous ceramic substrates produced by additive manufacturing. The filters were produced varying the coating thickness and processing parameters such as calcination time and temperature. A testing device was assembled to investigate the filters’ performance by exposing them in flowing water (240 Lh-1). The micropollutant adsorption was tested in three different water matrices (distilled water, surface water and wastewater treatment plant effluent). A range of 0.05 mg NH4–N g−1 up to 3.1 mg NH4– NH4–N g−1 zeolite of ammonium nitrogen was observed on the processed filters. Good filter stability expressed as weight loss (<5%) was observed. The adsorption of ten tested micropollutants showed an overall efficiency of 41.5% and 43% on the surface modified zeolite filters. Natural zeolite filters showed good specific adsorption capacity for metoprolol, citalopram, venlaflaxine and clarithromycin whereas the surface modified zeolite (SMZ) filters adsorb better hydrochlorothiazide, diclofenac, candesartan, mecoprop and irbesartan.

Enhancement of Bio-based para-Xylene Selectivity in Catalytic Fast Pyrolysis of Cellulose Using a Surface-modified Mg/P/HZSM-5 Catalyst

With the growing consumption of oil, the production of p-xylene(PX) from renewable biomass has gained significant attention recently. This work demonstrated that cellulose, a main component in lignocellulosic biomass, was directly converted into PX over the Mg/P surface-modified zeolites. The catalysts modified by the incorporation of P2O5 and MgO into HZSM-5(HZ) promoted the isomerization of m-/o-xylenes to p-xylene. The PX selectivity was greatly enhanced using the modified zeolites due to the deactivation of external surface and the adjustment of pore entrance. In addition, the addition of methanol to cellulose was beneficial to increase the selectivity of xylenes due to the alkylation reactions and the Diels-Alder reactions between cellulose-derived furans and methanol-derived olefins. The highest PX yield of 10.7%(molar fraction) with a high PX selectivity in xylenes(97.1%) was obtained over the 10%Mg/5%P/HZ catalyst. The reaction pathway for the formation of p-xylene was addressed according to the study of the key reactions and the characterization of catalysts.

Grafted zeolites for the removal of metal cations from crude oil hydrotreatment extract

Surface-modified zeolite Y has been synthesised and studied for potential application as an adsorbent for the removal of metal cations from aqueous solutions. Zeolite Y was synthesised under hydrothermal conditions at 100 °C in an autoclave and characterised by elemental analysis and thermogravimetric analysis to determine the chemical formula of the host material as Na54.91Al56Si136O384.246.5H2O. 3-Aminopropyltriethoxysilane (APTES) grafted zeolite Y was prepared by first preparing proton-exchanged zeolite Y using an 0.1 M ammonium nitrate solution followed by calcination at 350 o C. The APTES ligand was then grafted onto the protonated zeolite using three different solvent media. CHN analysis, FTIR spectroscopy, SSNMR and TG analysis indicated that the ligand was bonded covalently to zeolite Y attaching onto the inorganic surface through the available silanol groups. CHN analysis showed that hexane was the most effective solvent for carrying out ligand grafting, as indicated by the highest proportion of carbon present in the product after removal of free solvent (5.08%). APTES grafted zeolite Y was exposed to aqueous solutions containing different concentrations of divalent nickel cations (0.01 M to 0.1 M). An increase to 73.8% Ni (II) removal compared to 18.1% uptake by the parent zeolite Y without any graft was observed when the concentration of nickel was 0.01 M. The selectivity study using a solution containing five different transition metal cations; Ni (II), V (IV), Cu (II), Zn (II), and Fe (II) to mimic the species most often observed in hydrotreatment extract from crude oil, showed proportional removals of 83.7%, 91.3%, 82.8%, 70.6% and 85.7% respectively. This study indicates that APTES modified zeolite Y could be a useful material for the removal of catalytic poisons in hydroprocessing solutions during the processing of heavier crude oils.

Effect of zeolite surface modification with ionic liquid [APTMS][Ac] on gas separation performance of mixed matrix membranes

Abstract This study focuses on using a (3-aminopropyl)trimethoxysilane and acetate ion based ionic liquid to modify zeolite 4A as a filler in a polysulfone (PSf) membrane for CO2/CH4 and CO2/N2 separation, aiming at improving the polymer-filler interaction and separation performance of the mixed matrix membrane (MMM). The ionic liquid was covalently attached onto the zeolite surface. Zeolite modification was confirmed through FTIR analysis of pristine and modified filler. N2 sorption isotherms were used to characterize the porous structure, which showed decrease in surface area and pore volume after surface modification of zeolite. The crystal structure of zeolite 4A remained unaffected after modification with ionic liquid, as shown by XRD and SEM. Moreover, the synthesized PSf-based MMMs were tested in the separation of CO2 from CH4. Experiments were conducted at different temperatures and feed conditions, and pure and mixed gas permeability/selectivity data was reported. This modification of zeolites with methoxy groups containing cation and acetate anion based ionic liquid, resulted in an improved separation performance, as the modified filler enhanced the MMMs selectivity of CO2/CH4 by 37% and for CO2/N2 by 43% at 30 wt% filler loading as compared to pristine filler MMMs. The 3-(trimethoxysilyl)propan-1-aminium acetate coating acts as a selecting film which notably improves the selectivity at marginal expense of CO2 permeance.

PEG-template for surface modification of zeolite: A convenient material to the design of polypropylene based composite for packaging films

Abstract Zeolite was successfully modified by conventional synthetic route. Polyethylene glycol was employed for surface modification of zeolite. The surface of zeolite exhibited therefore hydrophobic properties. Less than 5 wt% of modified zeolites with uniform size and shape were integrated into polypropylene matrix. Mechanical properties of composite exhibited the similar trend compare to neat polypropylene. Oxygen transmission rate and water vapor transmission rate were evaluated and it exhibited the strong potential to be a good candidate material in active packaging.

Application of Zeolites for Sustainable Agriculture: a Review on Water and Nutrient Retention

Developing urbanization, water shortage, watercourse pollution, and demands for more food due to population growth require a more efficient water irrigation and fertilizer application. Retaining nutrients and water in agricultural soils brings about higher crop yields and prevents pollution of water courses. Among different solutions, zeolites, which are environmental friendly, ubiquitous, and inexpensive, have been extensively employed in agricultural activities. These minerals are considered as soil conditioners to improve soil physical and chemical properties including infiltration rate, saturated hydraulic conductivity (K s), water holding capacity (WHC), and cation exchange capacity (CEC). Natural and surface-modified zeolites can efficiently hold water and nutrients including ammonium (NH4 +), nitrate (NO3 −) and phosphate (PO4 3−), potassium (K+), and sulfate (SO4 2−) in their unique porous structures. Their application as slow-release fertilizers (SRFs) are reported as well. Therefore, zeolite application can improve both water use efficiency (WUE) and nutrient use efficiency (NUE) in agricultural activities and consequently can reduce the potential of surface and groundwater pollution. This review paper summarizes findings in the literature about the impact of zeolite applications on water and nutrient retention in the agriculture. Furthermore, it explores benefits and drawbacks of zeolite applications in this regard.

Development and introduction of a highly efficient catalyst for the butane–butylene fraction oligomerization process for the production of a high-octane automobile gasoline compound

The main stages in developing a technology for the production of high-silica ZSM-5 zeolite-based catalyst for the butane–butylene fraction (BBF) oligomerization process are described. The application of a new zeolite surface modification procedure allows the attainment of higher selectivity and target product yields (compared to familiar analogs) and the synthesis of more branched (and thus more high-octane) oligomers at lower pressures. The introduction of promoting metal Ga raises the target gasoline fraction yield by 0.9%, compared to the unpromoted catalyst. Comparative pilot tests of industrial (BAK-70U) and the developed (Ga-ZSM-5/Al2O3) BBF oligomerization catalysts are performed under the following conditions: pressure, 1.5 MPa; initial working temperature, 300°C; feedstock hourly space velocity (FHSV), 1.5 mL BBF/(mL cat h). It is shown that using modified ZSM-5 based catalyst results in a gasoline fraction yield 7% higher than with BAK-70U. The higher quality of the oligomerizate obtained on Ga-ZSM-5/Al2O3 is observed throughout the period of tests (191 h): MON is 2 points higher, and the concentration of gums is 50% lower. The results from these studies and tests are used for the development and industrial implementation of a technology for the production of the KOB-1 zeolite oligomerization catalyst: 2.5 t of industrial catalyst has been produced by September of 2016 at the industrial facilities of ZAO Redkino Catalyst Plant. The next important stage in the implementation of the Gazprom Netf innovative development strategy in oil refining is a pilot run of the new oligomerization catalyst in the combined industrial MTBE–oligomerizate production plant of Gazprom Neft Moscow Oil Refinery. The introduction of the KOB-1 catalyst at the Gazprom Neft Oil Refinery will be an important step in improving the efficiency of technologies for the production of high-margin products, especially compounds of commercial automobile gasoline.