Ethylene Adsorption Capacity Research Articles

Surface Molding Hydrogel Film Initiated by ZIF-8 with Ethylene Adsorption Performance for Preserving Perishable Fruits.

The quality deterioration of postharvest fruits is greatly influenced by ethylene, leading to food wastage worldwide. Therefore, it is urgent to develop an efficient packaging strategy to reduce ethylene concentration and prolong the shelf life of perishable fruits. In this work, a surface-molding hydrogel film was created using ZIF-8 in combination with carboxymethyl starch (CMS) and carboxymethyl chitosan (CMCS). Specifically, ZIF-8 is first anchored on CMS and then rapidly cross-linked in situ with CMCS, forming ZIF-8@CC on the fruit surface (within 10 s). The perfect tight-fitting effects of ZIF-8@CC were observed on various fruit surfaces with different roughness (Ra: ranges from 102 to 308 nm). ZIF-8@CC could absorb 57.3% endogenous ethylene from bananas, and the interaction mechanism between ethylene and ZIF-8 was studied by molecular dynamics simulations, providing insights into the ethylene adsorption capacity of ZIF-8@CC. Moreover, ZIF-8@CC presented excellent antibacterial properties and achieved satisfactory ultralong preservation effects on both nonclimatic and climatic fruits (12 days for strawberries and 14 days for bananas) at room temperature. Importantly, ZIF-8@CC is easily removed, washed, and degradable. These findings offer an efficient and potential food packing material with multifunctional properties for preserving perishable fruits.

Novel ethylene scavenger based on sillimanite and bentonite clay for packaging applications: A sustainable alternative for preservation of fresh produce

Natural and chemical-free material in food packaging applications has gained interest globally with increasing demand for human health and environmental concerns. The present research aimed to develop a mineral and clay-based ethylene scavenger by mixing Sillimanite (Al2SiO5) and Bentonite (Al2H2O6Si) at different ratios to protect the deterioration of fruits and vegetables. The samples were prepared in different proportions of Sillimanite and Bentonite on a weight basis and named SL/BT (100:0), SL/BT (80:20), SL/BT (70:30), and SL/BT (50:50). The ethylene adsorption capacity of the samples was studied for 21 days under three conditions, i.e., 29±3 °C and 55 ± 3% RH, 25 °C and 75 ± 2% RH, 55 °C, and 99 ± 1% RH. The scanning electron microscopy (SEM) result determines the average particle size of sillimanite (80–100 nm) and bentonite (80–110 nm. Brunauer-Emmett-Teller (BET) result shows the surface area and pore volume of the sillimanite (8.42 m2/g and 0.039 cc/g) and bentonite (20.765 m2/g, 0.073 cc/g), higher surface area and pore volume result in higher ethylene adsorption. FTIR was performed to analyze the functional group changes after ethylene adsorption. The samples kept at 29±3 °C and 55 ± 3% RH showed the highest ethylene adsorption capacity of 84%. From the above study, the mineral clay-based material can effectively enhance the shelf life of fruits and vegetable packaging.

Ethylene Scavenger from Brick Ash: A Sustainable Alternative

Most commercially available ethylene scavengers are based on potassium permanganate (KMnO4) which have limitations due to food safety issues. In the present study, an industrial byproduct brick ash that has a significant capacity to adsorb ethylene at room temperature is reported. The material is subjected to thermal treatment for activation and subsequently characterized by scanning electron microscopy (SEM), particle size and surface analysis, Fourier transform infrared (FTIR) spectroscopy studies, and elemental composition analysis. A significant change was observed in the surface morphology of brick ash obtained from SEM and Brunauer–Emmett–Teller (BET) analysis wherein the surface of brick ash became highly porous after being activated at 1000 °C. This was accompanied by reduction in the average particle size of brick ash to <250 μm. The ethylene adsorption capacity was estimated using a 200-ppm commercial ethylene gas stream. It was observed that observed that the ethylene adsorption capacity increased from 52.5 ± 3.5 μL/g to 187.28 ± 6.2 μL/g as the temperature of activation varied from 500 °C to 1000 °C, respectively. The adsorption of ethylene on the brick ash was confirmed by the observance of FTIR peaks at 1380 and 1872 cm–1. The practical applicability of the developed ethylene scavenger was evaluated through shelf life studies on bananas, conducted at 22–24 °C and 65% relative humidity. Analysis of various quality parameters concluded that the treated sample showed an increase in shelf life of 8 days, compared to the control sample. The comparison was made with commercially available KMnO4-based ethylene scavengers that showed similar scavenging capacity. Thus, brick ash can be an effective and sustainable alternative ethylene scavenger to extend the shelf life of ethylene-sensitive fresh produce.

Regulation of the nature and sites of copper species in CuNaY zeolites for ethylene and ethane separation

Relationship between the states of Cu species and ethylene adsorption capacity.

Development of a novel ethylene scavenger made up of pumice and potassium permanganate and its effect on preservation quality of avocados

The purpose of this research was to develop a novel ethylene scavenger by combining pumice and potassium permanganate (KMnO 4 ) to preserve fruit and vegetables. The study showed that pumice with smaller particle sizes and lower relative humidity (RH) were favorable to ethylene adsorption. The optimal ratio was 1 g of pumice (<5 μm) to 100 mg of KMnO 4 with approximately 620 μL/g of ethylene adsorption capacity within 24 h at lab room RH (30%). Further, this novel ethylene scavenger restricted the ethylene production rate of avocados to 0 μL/kg/h for nine days, and simultaneously, the carbon dioxide (CO 2 ) production rate remained below 25 mL/kg/h. In addition, the firmness of avocados preserved by the novel ethylene scavenger was 4.04 × 10 5 N/m 2 on the 9th d. The results confirmed that the shelf life of avocados was extended by one week at 25 °C under the preservation of the novel ethylene scavenger. • Smaller particle size and lower relative humidity favored ethylene removal. • Pumice physically adsorbed ethylene and KMnO 4 oxidized ethylene. • Ethylene and CO 2 production rate were restricted by the ethylene scavenger. • The ethylene scavenger could extend shelf life of avocados by one week.

An anti-humidity palladium-containing MFI composite as a robust ethylene scavenger

The inhibition of ethylene exposure is necessary for preserving the quality of postharvest fruit and vegetables. In this study, we report a rational design of Pd-based MFI composite adsorbents consisting of Pd-ZSM-5 and S-1 zeolites with high ethylene adsorption capacity even in the humid environment. The effects of S-1 incorporation on the morphology, apparent surface area, Pd nanoparticles distribution, and the hydrophobicity of the MFI composite were investigated in relation to their ethylene adsorption performance in dry and humid environments. Our finding reveals a synergistic effect between the Si-rich layer and Pd nanoparticles on moisture protection and ethylene capture, respectively, leading to an exceptional ethylene adsorption ability of S-1/Pd-ZSM-5 under high relative humidity. Compared with the conventional ZSM-5-supported Pd adsorbent, S-1/Pd-ZSM-5 exhibited a two-fold enhancement in ethylene removal in the presence of moisture (0.195 mmol/g vs. 0.416 mmol/g). In particular, the secondary crystallization of S-1 achieved by 72 h of hydrothermal treatment gave an excellent confinement over the Pd-ZSM-5 structure. This novel design of S-1/Pd-ZSM-5 provides the valuable applicability of the composite zeolite for ethylene regulation in postharvest crops in the future.

Sepiolite as an efficient adsorbent for ethylene gas

AbstractThe ability of Na+-, Li+-, K+-, Ca2+- and Mg2+-exchanged sepiolites and acid-activated sepiolites to remove ethylene from storage environments was examined. The sepiolite from Sivrihisar deposit, Turkey, was treated with 1.0 M NaNO3, LiNO3, KNO3, Ca(NO3)2, Mg(NO3)2, HNO3 and H2SO4 solutions at 90°C for 4 h. The mineralogical, chemical and textural properties of the materials were examined using X-ray diffraction, X-ray fluorescence, cation-exchange capacity and nitrogen gas adsorption analyses. The main mineral phase present in the materials was sepiolite, with minor dolomite, and traces of quartz and feldspar minerals and amorphous matter. Adsorption isotherms of ethylene at 273 K were measured on sepiolite samples over a pressure range of 0–100 kPa. As a result of partial blockage of the sepiolite channels, the ethylene adsorption capacity on cation-exchanged sepiolite forms (0.376–0.907 mmol g–1) was less than that of acid-activated sepiolite forms (1.279 and 1.308 mmol g–1). The ethylene adsorption capacities of the sepiolite samples were compared with those of other clay-based materials (0.167–1.817 mmol g–1) reported in previous studies of ethylene removal.

Miniplant-Scale Demonstration of Ethylene Adsorption Separation in Downstream of an Oxidative Coupling of Methane Process

Developing an efficient sorbent and adopting an ethylene adsorption separation unit in downstream of an oxidative coupling of methane (OCM) process were the main focus of the present study. Since the mole fraction of the generated ethylene in the OCM reactor outlet is relatively low, the processing cost of the accompanying components and thereby the separation cost per ton of ethylene using the conventional cryogenic separation are insupportable. Zeolite 13X was modified in this research, demonstrating outstanding ethylene adsorption capacity and selectivity. The conducted adsorption experiments at a miniplant-scale unit enabled monitoring the adsorption breakthrough times and measuring the sorbents’ capacity under different operating pressures in the range of 1–5 bar while processing different feed flow and feed compositions, representing the attachment of the adsorption unit to different parts of the OCM process. The modified zeolite 13X showed superior performance than the reference sorbents such as zeolite 4A and activated carbon. Physical treatment of zeolite 13X, by calcining it at 550 °C, proved to be efficient in increasing its adsorption capacity. Chemically treating zeolite 13X via copper exchange on the other side increased its ethylene adsorption selectivity in competition to CO2 adsorption. In processing the CO2-rich feed streams (with the CO2 content 2.25 times of its C2H4 content), the Cu-exchanged zeolite 13X showed a promising ethylene adsorption capacity of 0.46 molC2H4·kgs–1 combined with an adsorption selectivity of 0.45 molC2H4·molCO2. In processing the CO2-free feed streams (with the C2H4 content 2.75 times of its C2H6 content), using the calcined zeolite 13X secured the highest adsorption capacity of 1.4 molC2H4·kgs–1 along with an adsorption selectivity of 3.8 molC2H4·molC2H6 under 5 bar adsorption pressure. These indicate the promising potentials of the developed sorbents and the designed adsorption unit for processing the OCM reactor outlet gas stream before and after removal of its CO2 content.

Realization of Ethylene Production from Its Quaternary Mixture through Metal-Organic Framework Materials.

Ethylene production from oxidative coupling of methane is a sustainable and economically attractive alternative to that through traditional hydrocarbon cracking technology. However, efficient ethylene separation from the complex reaction mixture is a daunting challenge that hinders the practical adoption of this technology. Herein, we report the efficient adsorptive separation of the CH4/CO2/C2H4/C2H6 mixture using three representative metal-organic frameworks (MOFs) (UTSA-74, MOF-74, and HKUST-1) with diverse open metal sites. The efficient separation relies on tuning the selectivity through the convergence of characteristics including Lewis acidity of open metal sites, pore space, and cooperative binding behavior. The separation performance of these materials has been evaluated through single-component gas adsorption and dynamic breakthrough experiments. HKUST-1 provides the highest separation potential (4.1 mmol/g) thanks to its simultaneously high ideal adsorbed solution theory (IAST) selectivity and ethylene adsorption capacity, representing a benchmark material for such a challenging quaternary separation.

Ethylene adsorption on chitosan/zeolite composite films for packaging applications

• A film of chitosan and natural zeolite has been evaluated for ethylene release control. • Ethylene equilibrium of adsorption was measured gravimetrically. • Ethylene adsorption capacity was affected by zeolite amount and film drying process. • Chitosan/zeolite film chose for ethylene is based on the product to be packed. Ethylene is the hormone responsible for the development and ripening of fruits and vegetables. Thus, in order to extend the postharvest shelf life, its accumulation should be avoided. Films, dense and porous, composed of chitosan/zeolite (CZ), were obtained using chitosan as support for clinoptilolite zeolites. These films were characterized by nitrogen and carbon dioxide adsorption isotherms, water vapor permeability and ethylene adsorption capacity. Zeolites distribution and the development of the pores were observed by scanning electron microscopy. Films were dried (partially or totally) by a convective process, followed or not by lyophilization. Lyophilized-CZ (with 93 % zeolite (CZ93 L) showed adsorption capacity similar to that of pure zeolite regenerated at 90 °C (ZR90) and higher than CZ93. Dense-chitosan films (DCF), porous-chitosan films (PCF) and CZ33 (33 % zeolite) exhibited small amounts of adsorbed ethylene when compared to the other materials. Based on these results, the chitosan/zeolite films may be viable for packaging applications.

Developing self-activated lignosulfonate-based porous carbon material for ethylene adsorption

This study applied lignosulfonate as raw material to develop porous carbon for ethylene adsorption, followed by testing for this material's ethylene adsorption efficiency and capacity. The results indicated that the gas released (CH4, H2, CO, and CO2) during pyrolysis could generate a pore structure on lignosulfonate-based carbon surface, regarded as the self-activated mechanism. Pore structure formation increased pore volume and resulted in generation of various pore shapes. When carbonization temperature was less than 800 °C, specific surface area of the samples increased with temperature, and it decreased otherwise. Moreover, with increasing carbonization temperature, the samples’ carbon content increased but hydrogen content decreased. Ethylene adsorption uptake increased as carbonization temperature increased. Adsorption capacity was maximum when carbonization temperature was 800 °C. It was influenced by the pore structure, and specifically, it increased as micropore volume increased. In addition, physical adsorption was the main mechanism of ethylene adsorption for the lignosulfonate-based porous carbon, leading to efficient adsorption-desorption cycles. Finally, its application as an ethylene scavenger can potentially transcend currently available products.

Characterizing Adsorption Sites on Ag/SSZ-13 Zeolites: Experimental Observations and Bayesian Inference

Three potential adsorption sites within the Ag/SSZ-13 zeolite are compared for their ethylene and water adsorption capacity. Ethylene acts as a model hydrocarbon molecule in this work to stand in f...

Alkaline halloysite nanotubes/low density polyethylene nanocomposite films with increased ethylene absorption capacity: Applications in cherry tomato packaging

Halloysite nanotubes (HNTs) are hollow tubular clay nanoparticles used as nanofillers to remove or minimize the production of ethylene gas. The presence of ethylene gas leads to reduced shelf life in fruits and vegetables by accelerating postharvest softening and aging. Alkaline solution-treated HNTs have increased ethylene adsorption capacity due to an increased number of OH groups on the HNTs external surface. This study reports on the thermal, morphological, and mechanical properties of alkaline HNTs (ALK-HNTs) loaded into a low-density polyethylene (LDPE) matrix. Our results indicate that, although the mechanical properties of the LDPE matrix films were not improved with loading ALK-HNTs, the oxygen barrier property were improved and ethylene gas adsorption increased by 220 %. Cherry tomatoes packaged in a 3% ALK-HNTs/LDPE nanocomposite film and stored at 8 °C for 21 days showed a reduction in loss of firmness and weight by 17.0 % and 36.7 %, respectively.

Use of a Copper- and Zinc-Modified Natural Zeolite to Improve Ethylene Removal and Postharvest Quality of Tomato Fruit

Ethylene stimulates ripening and senescence by promoting chlorophyll loss, red pigment synthesis, and softening of tomatoes and diminishes their shelf-life. The aim of this work was to study the performance of a novel copper- and zinc-based ethylene scavenger supported by ion-exchange on a naturally occurring zeolite by analyzing its ethylene adsorption capacity and the influence of ethylene scavenging on quality attributes during the postharvest life of tomatoes. The influence of copper- and zinc-modified zeolites on ethylene and carbon dioxide concentrations and postharvest quality of tomatoes was compared with unmodified zeolite. Interactions among ethylene molecules and zeolite surface were studied by diffuse reflectance infrared Fourier transform spectroscopy in operando mode. The percentage of ethylene removal after eight days of storage was 57% and 37% for the modified zeolite and pristine zeolite, respectively. The major ethylene increase appeared at 9.5 days for the modified zeolite treatment. Additionally, modified zeolite delayed carbon dioxide formation by six days. Zeolite modified with copper and zinc cations favors ethylene removal and delays tomato fruit ripening. However, the single use of unmodified zeolite should be reconsidered due to its ripening promoting effects in tomatoes at high moisture storage conditions, as water molecules block active sites for ethylene adsorption.

Effect of doping natural zeolite with copper and zinc cations on ethylene removal and postharvest tomato fruit quality

Tomatoes (Solanum lycopersicum L.), one of the most consumed vegetables worldwide, are climacteric fruit in which ripening is accompanied by quickly increased respiration and ethylene production. Ethylene stimulates ripening and senescence that finally may result in detrimental effects by promoting unwanted softening, grainy structure, accelerated pigment synthesis and chlorophyll loss in tomatoes. Therefore, most postharvest technology strategies are focused on the minimization of ethylene production, inhibition of its action and removal of ethylene from storage facilities. The aim of the present work was to study the ethylene adsorption capacity of a novel copper-zinc-based ethylene scavenger supported on natural zeolite and the effects of ethylene scavenging on quality attributes of tomatoes during their postharvest shelf life. Tomatoes (control, natural zeolite, zeolite doped with copper and zinc) were stored in hermetically sealed glass desiccators, in darkness at 20 °C and a relative humidity of 88 %. Production rates of ethylene and carbon dioxide were determined during 15 days of storage of tomato fruit by monitoring their headspace concentrations as a function of time using gas chromatography. Physical parameters, such as size, weight, colour and texture, and chemical attributes, including moisture, soluble solids, titratable acidity, reducing sugars and lycopene, were determined at the start of the experiment and after 8 and 15 days of tomato storage. Ethylene production diminished in 50 % for modified zeolite and in 7 % for natural zeolite during the first week, while major concentration peaks appeared for both zeolite treatments at 9.5 days. Moreover, modified zeolite delayed tomato respiration during the first six days. This adsorbent was able to shift the respiration peak compared to control treatment in time due to the incorporation of copper and zinc. Increased respiration and ethylene production rates in presence of both zeolites after 1 week of tomato storage trigger the decay of organic acids and part of the soluble solids. In addition, natural zeolite significantly reduced Young’s modulus at the end of storage, which can be attributed to the increased ethylene accumulation of about 40 % compared to control tomatoes. Furthermore, red colour evolution was promoted by natural zeolite, while modified zeolite induced the greatest delay of colour development in tomatoes. Additionally, the use of natural zeolite results to significantly higher increase of lycopene synthesis compared to tomatoes stored in presence of modified zeolite. Natural zeolite doped with copper and zinc cations favours ethylene removal and delays tomato fruit ripening. However, the single use of natural zeolite should be reconsidered due to its ripening promoting effects in tomatoes. Finally, the incorporation of copper and zinc cations to a zeolite support is a new, emergent postharvest technology to slow down fruit ripening that may create new commercial opportunities for fresh-market tomatoes.

Ethylene Adsorption Using Cobalt Oxide-Loaded Polymer-Derived Nanoporous Carbon and Its Application to Extend Shelf Life of Fruit.

Suppressing the amount of ethylene during storage has been of interest as a method to enhance shelf life of fruit. In this work, ethylene removal by adsorption using cobalt oxide-impregnated nanoporous carbon has been studied. Nanoporous carbon with a high surface area up to 2400 m2 g−1 was prepared by carbonization process biomass and synthetic polymer at 850 °C. Dispersion of cobalt oxide on porous carbon surface was carried out by an incipient wetness procedure followed by calcination process at 200 °C. Ethylene adsorption test was performed using a volumetric method in an ultrahigh vacuum rig constructed by Swagelok VCR® fittings. The results showed that the cobalt oxide/carbon system had significant ethylene adsorption capacity. Ethylene uptake increases with the increasing cobalt oxide loading on the carbon. The highest ethylene capacity of 16 mol kg−1 adsorbent was obtained by using 30 wt.% (weight percentage) of cobalt oxide dispersed in polymer-derived carbon. In closed storage, the ratio of 15 g adsorbent/kg fruit may extend the storage life up to 12 d, higher than that without adsorbent (3 d). Therefore, the results demonstrate the great potential use of cobalt oxide-impregnated nanoporous carbon as an adsorbent for ethylene removal during storage of fruit.

Silver nanocluster in zeolites. ADSORPTION of ETHYLENE traces for fruit preservation

Abstract Removal of trace amounts of C2H4 from air streams at low temperature is technologically important for fruit preservation in warehouses. For that reason, a systematic quantitative and comparative study of Ag-zeolites for trace ethylene adsorption has been carried out. Combining characterization results with trace ethylene adsorption in a fixed-bed system have allowed to stablish a correlation between Agδ+ species present in the zeolites and trace ethylene adsorption capacity. Among the zeolites studied, silver exchanged zeolites with -CHA (SSZ-13) and -LTA (5A) frameworks exhibited the most stable and highly dispersed silver sites, with an excellent potential for indoor environmental control of trace ethylene at 0 °C.

Removing Ethylene by Adsorption using Cobalt Oxide-Loaded Nanoporous Carbon

Ethylene is naturally generated by climacteric fruits and can promote the ripening process faster. For effective long-distance transport and subsequent storage, removing ethylene from the storage environment has been of interest to suppress its undesirable effect. In this study, ethylene removal by an adsorptive method using cobalt-loaded nanoporous carbon is studied. Cobalt oxide-loaded carbon was prepared by incipient wetness method followed by calcination process at 200 °C under inert flow. Ethylene adsorption test was performed at 20, 30, and 40 °C using a static volumetric test. The results showed that cobalt oxide/carbon system has significant ethylene adsorption capacity up to 3.5 times higher compared to blank carbon. A higher temperature adsorption is more favorable for this chemisorption process. Ethylene uptake increases from 100 to 150 mL g-1adsorbent STP by increasing cobalt oxide loading on carbon from 10 to 30 wt.% Co. The highest uptake capacity of 6 mmol ethylene per gram adsorbent was obtained using 30 wt.% cobalt oxide. Therefore, ethylene adsorption by cobalt-loaded nanoporous carbon may represent a potential method in ethylene removal and it could serve as a basis for development of ethylene scavenging material.

High adsorption of ethylene by alkali-treated halloysite nanotubes for food-packaging applications

Fresh food products such as fruits and vegetables are usually degrading fast after harvest, notably due to the production of ethylene, an aging hormone, by the products. Therefore, ethylene adsorbents in the form of powders are commonly used in packaging to maintain the postharvest quality of fresh products. The use of naturally-based adsorbents is preferred for safe food-packaging applications. Here we studied halloysite nanotubes as natural ethylene scavengers. We tested the effect of storage conditions on the kinetics of ethylene adsorption. Raw halloysite nanotubes were subjected to alkaline treatment to increase their pore size. We compared the efficacy of raw halloysite nanotubes versus alkaline halloysite nanotubes. Materials were characterized by Fourier transform infrared spectroscopy, thermogravimetric analysis, and transmission electron microscopy. Results show that alkali-treated halloysite nanotubes have the highest ethylene adsorption capacity at 11% relative humidity and 23 °C. The ethylene adsorption kinetics data were slightly fitted to a pseudo-first-order model, and the rate constant of the ethylene adsorption was 0.7107 min−1. After 24 h, 49 μL of ethylene gas present in headspace was removed with 1 g of alkali halloysite nanotubes.

Preparation of porous carbon as ethylene adsorbent by pyrolysis of extraction waste Mangosteen rinds

Mangosteen rind is an important source of natural antioxidants. Due to the growing interest in extracting this anti cancer substances from the Mangosteen rind, the amount of this lignocellulosic residu has been generated significantly as byproduct. In this research, extraction-waste Mangosteen rind (EMP) was used as alternative precusor for production of carbon-based adsorbent for ethylene removal. Steam was used as activating agent and the effect of carbonization time and temperature on the development of pore structure were examined. Pyrolysis process was carried out by heating the Mangosteen rinds powder (180 μm - 355 μm) from ambient temperature up to carbonization temperature of 848 K and kept for 3 hours then followed by heating up to 1123 K and kept for 15 minutes under flowing N2 and steam. This process was repeated for several pyrolysis temperature (1053 K, 1073 K, 1083 K and 1103 K) and carbonization time (0 hours, 1 hour, 2 hours, and 3,5 hours). The carbon obtained was characterized in terms of its pore structure and ethylene uptake capacity. The results show that porous carbon obtained from pyrolysis of extraction-waste Mangosteen rind can be characterized as mesoporous carbon. The highest surface area of 1080 m2/g was obtained from pyrolysis of extraction-waste Mangosteen rinds with carbonization time of 3.5 hours and pyrolysis temperature of 1123 K. Furthermore, the mesopore portion and the specific surface area increased with the increasing carbonization time. From the ethylene uptake experiment, it was noted that the ethylene adsorption capacity of EMPC is 40.12 cm3/g.