Effect of zeolite types on properties of polybutylene succinate/polylactic acid films

The performance of zeolites 5A and 13X is numerically investigated in oxygen separation from air by a two-bed PSA system. The effect of operating variables such as adsorption step time, P H /P L ratio and cycle time was investigated on product purity and recovery. The simulation results showed that nitrogen adsorption capacity on zeolite 13X was slightly more than the one on zeolite 5A. In the completely same operating conditions, zeolite 5A had a larger mass transfer zone than zeolite 13X. Therefore, the adsorption and desorption rate of nitrogen on zeolite 5A is less than zeolite 13X. Moreover, for the equal volume of adsorbed nitrogen on both adsorbents, zeolite 5A is more capable rather than zeolite 13X to desorb much more volume of nitrogen at certain time. Furthermore, for achieving oxygen with purity of 96%, utilizing zeolite 5A is more economical than zeolite 13X, when 5.5<P H /P L <7 and 75<cycle time≤90.

The present study aimed to investigate the adsorption behavior of heavy metal ions (Cu 2+ , Cd 2+ , and Pb 2+ ) on zeolite 4A (26.9 m 2 /g) and zeolite 13X (550.1 m 2 /g) at neutral pH in batch experiments. Influencing parameters on the adsorption were studied, including equilibrium time, solution pH, and adsorbent dose. The metal removal efficiencies at neutral pH were considerably higher than those at acidic pH. Cu 2+ and Cd 2+ were more efficiently adsorbed on zeolite 4A, while the greater removal of Pb 2+ was achieved with zeolite 13X. With an initial concentration of 300 ppm and an adsorbent‐to‐liquid ratio of 0.2% w/v, the highest removal efficiencies were 91.1% for Cu 2+ and 95.2% for Cd 2+ with zeolite 4A, and 92.9% for Pb 2+ with zeolite 13X. The experimental data fitted well with the Langmuir isotherm and the pseudo‐second‐order models, indicating the monolayer formations and the dominance of chemisorption. Zeolite 4A showed higher pseudo‐second‐order rate constants than zeolite 13X. The intraparticle diffusion contributed more significantly to the adsorption of Cu 2+ and Cd 2+ than that of Pb 2+ on the zeolites. The findings from this study provide valuable insights into the adsorption behavior of heavy metals on different kinds of zeolites in neutral solution.

In a way to overcome challenges with global warming, the use of fossil fuels in producing environmentally friendly energy towards reducing the ozone layer depletion and greenhouse gas emissions by participating countries is of interest. The adsorption refrigeration system has the advantages of a long lifespan and its environmental friendliness; however, its major disadvantage is the low coefficient of performance, which is a function of adsorbent–adsorbate, with zeolite–water as the most common adsorbent–adsorbate working pair. Zeolites 4A and 13X are the most used zeolite classes due to their higher selectivity for separating mixtures of CO2/N2 and CO2/CH4/N2 and their high-water adsorption capability, respectively. In this study, for the first time, the synthesis of zeolites 4A and 13X from natural sources (Kankara kaolin) and the mixture optimization for solar adsorption refrigeration application were considered. Raw Kankara kaolin, beneficiated Kankara kaolin, calcined Kankara kaolin and synthesized zeolites 4A and 13X were characterized using X-ray fluorescence, while the synthesized zeolites 4A and 13X were characterized using X-ray diffraction. Using the mixture simplex lattice design of experiment, mixtures of zeolites 4A and 13X were developed and characterized using Brunauer, Emmett and Teller analysis to obtain their pore size, specific surface area and pore volume. The statistical analysis produced the mathematical models of the response that were significant for pore size and specific surface area. The analysis proposed an optimal solution of 75 wt% zeolite 4A and 25 wt% zeolite 13X, which gave a desirability of 0.944.

Adsorptive removal of ultra-low concentration H2S and THT in CH4 with and without CO2 on zeolite 5A and 13X pellets

Zeolite filled P84 co-polyimide membranes for dehydration of isopropanol through pervaporation process

In this research, the biodegradable film of poly (butylene adipate-co-terephthalate) (PBAT) would be used as the polymer matrix. The influence of zeolite (as the filler) type and content were investigated on the mechanical and barrier properties of film packaging. Zeolite was treated with (3-aminopropyl) trimethoxy silane. Films were produced by cast film extruder. Effects of different types of zeolite (5A and 13X) as well as zeolite loading (1-5 wt%) on mechanical properties and permeability of gases (oxygen, carbon dioxide and water vapor) of PBAT composites films have been extensively studied. Tensile properties of PBAT incorporated with zelolite 5A are higher than the one with zeolite 13X. In addition, increasing zeolite content into PBAT film is likely to improve Young’s modulus with the sacrifices of both tensile strength and percentage of elongation at break of PBAT film. For barrier properties, PBAT/zeolite 5A possessed lower permeation both of oxygen and carbon dioxide gases than PBAT/zeolite 13X. The effect of zeolite content plays a major role on oxygen and carbon dioxide permeability of composite films. PBAT/zeolite composite film could certainly extend the ripening period of Homthong bananas for approximately longer than one week.

Adsorption isotherms are reported for pure carbon dioxide and water vapor on 5A and 13X zeolite beads and silica gel granules. These data were obtained using a volumetric method and cover the temperature ranges of (−45 to 175) °C for carbon dioxide and (0 to 100) °C for water. Also, pure carbon dioxide isotherms on silica gel at temperatures from (10 to 55) °C were measured using a gravimetric apparatus. All pure component equilibria are described well by Toth isotherms with parameters having temperature dependence. For carbon dioxide adsorption, zeolites 5A and 13X have similar loadings and show a much higher capacity than silica gel. However, for water vapor, zeolite 13X has a slightly higher capacity than zeolite 5A. Both zeolites have very good adsorption capacities for water vapor at low pressures but lose their advantages to silica gel when water pressures are high.

The influence of modified zeolites as nucleating agents on crystallization behavior and mechanical properties of polypropylene

Adsorption and desorption experiments for the binary mixture (N2/O2; 79:21 vol%) on zeolite 5A, 10X, and 13X beds were performed to study the dynamic characteristics of air separation adsorption processes. Because the breakthrough and desorption curves showed a tail by temperature variance in the beds, a nonisothermal dynamic model incorporating mass and energy balances was applied to the simulation of adsorption dynamics using the Langmuir–Freundlich model and the LDF approximation. The breakthrough and desorption results were compared among three different beds with respect to the breakthrough and desorption times, tailing effect, and temperature variation with the effects of pressure and flow rate. On the basis of the similar bed density, the order of breakthrough time and desorption time was zeolite 10X, 13X, and 5A beds. Also, the O2 MTZ of the zeolite 10X bed was slightly sharper than those of the zeolite 5A and 13X beds due to more favorable N2 isotherm of zeolite 10X. Furthermore, the breakthrough curve of the zeolite 13X bed showed a relatively long tail. In addition, the breakthrough curves of the zeolite 5A and 13X were similar to adiabatic behavior, whereas that of the zeolite 10X bed showed an isothermal behavior. The N2 desorption experiments were performed by O2 purge under the high pressure conditions. The desorption behaviors were very similar to the results of the breakthrough study, while the thermal effect on the desorption curve was negligible at the beds. The tails of the desorption curves were prominent with a change in the purge flow rate and desorption pressure. In all the beds, the feed and purge rates were more important factors for deciding the breakthrough and desorption times than the adsorption and desorption pressures in the experimental range.

Zeolites as sensitive materials for organic vapour detection: an exploratory study

In this study, new monomers having silica groups were synthesized as an intermediate for the preparation of poly(imide siloxane)-zeolite 4A and 13X mixed matrix membranes (MMMs). The effects of membrane preparation steps, zeolite loading, precursor’s composition, and pore size of zeolite on the gas separation performance of these mixed matrix membranes were studied. The new diamine monomer was prepared from 3,5-diaminobenzoic acid (3,5-DABA), 3-aminopropyltrimethoxysilane (3-APTMS), and zeolite 4A and zeolite 13X in N-methyl-2-pyrollidone (NMP) at 180 °C. Poly(imide siloxane)-zeolite 4A and 13X MMMs were synthesized from pyromellitic dianhydride (PMDA) and 4,4-oxydianiline (ODA) in NMP using a two-step thermal imidization. SEM images of the MMMs show the interface between polymer and zeolite phases getting closer when surface modified zeolite is used. The increase in glass transition temperature (Tg) confirms the polymer chain becoming more rigid induced by the presence of zeolite. The experimental results indicated that a higher zeolite loading resulted in a decrease in gas permeability and an increase in gas pair selectivity. In terms of O2 and N2 permeance and ideal selectivity, the separation performances of poly(imide siloxane)-zeolite MMMs were related to the zeolite type and zeolite pore dimension.

The comparison of adsorption characteristics of CO2/H2O and N2/H2O on activated carbon, activated alumina, zeolite 3A and 13X

Aspen adsorption simulation for the effects of purge flow rate and vacuum pressure in vacuum pressure swing adsorption

Experimental measurements and modeling of supercritical CO2 adsorption on 13X and 5A zeolites

The adsorption isotherms of nitrous oxide (N2O) on zeolite 5A, 13X, activated carbon, ZSM-5, and silica gel were investigated by a static volumetric method. The pressure and temperature by measurement of adsorption isotherms ranged from 0 to 1 MPa and 298 to 358 K, respectively. In terms of the adsorption amount, zeolite 13X has the highest adsorption capacity at high pressure (>0.7 MPa), while activated carbon has the best performance at low pressure (<0.1 MPa). The Langmuir, Langmuir–Freundlich, and Toth models were employed to describe the isotherm data, and the Langmuir–Freundlich model showed the best correlation with experimental isotherm data on all adsorbents. In addition, the temperature-dependent Langmuir–Freundlich model was used to fit the N2O adsorption data on all adsorbents. The isosteric heats of N2O on all five adsorbents were calculated. The heat of N2O adsorption on 5A was up to 51.1 kJ/mol, which was the highest compared to 13X, activated carbon, ZSM-5, and silica gel.