Sorption Of Organic Compounds Research Articles

Nanocomposites with polyurethane polymer matrix/ particulate material

The environment is currently considered one of the main concerns of the industrial sector and society. In the particular case of the oil industry, one of the biggest environmental catastrophes that can happen are large oil spills, where to reduce or minimize the environmental damage caused, various cleaning methods are used. Thus, nanocomposites aim to change the mechanical, physical and chemical properties of polymer matrices. The main focus of modifying Polyurethanes has been directed to materials science, the objective of which is to obtain particulate materials, allowing surfaces to be differentiated, reducing surface energy and increasing interlayer spacing for polymer intercalation. This particulate material, produced and modified, interspersed with the Polymer, allows us to absorb crude oil, as it is hydrophobic and, consequently, organophilic. The factors that define the degree of sorption of organic compounds are: hydrophobicity, porosity, molecular structure and volume, and the volume of the surface area of the sorbent material. Therefore, the sorbent must be wettable by the hydrophobic compound and non-wettable or slightly wettable by water. Sorbent materials must have characteristics such as a large surface area, high porosity, good oleophilic character, as well as good oil retention capacity and ease of application. Polyurethane presents several of these characteristics, making it an interesting sorbent for the oil sector. The present work studies the obtaining of these nanocomposites, using a particulate material to combat leaks or spills of hydrocarbons.

New architecture based on Metal-Organic Frameworks and spin crossover complexes to detect volatile organic compounds.

We present here the encapsulation of a spin crossover complex C1 [FeII(L)] (L: 4-amino-, 2-(2-pyridinylmethylene)hydrazide) inside MOF-808(Zr), a chemically robust Metal-Organic Framework. The compound C1⊂MOF-808 retains its crystallinity as well as a partial porosity compared to pristine MOF and shows solvatochromism under Volatile Organic compounds (VOCs) sorption associated to a spin state change of the guest complex. More specifically, this compound shows an interesting reversible color change under formaldehyde and formic acid vapor sorption and can therefore be considered as a new kind of optical VOCs chemosensor, opening new doors for developing a broad range of VOCs optical sensors.

Micro- and Mesoporous Structural Effects of Beta Zeolites for Volatile Organic Compound Sorption.

To fully exploit pore engineering in the design of more efficient zeolite adsorbents for volatile organic compound (VOC) treatment, the roles of meso- and micropores need to be clarified to provide the theoretical basis and feasible measures. In this work, the three VOC sorption properties of conventional and hierarchical porous beta zeolites were comparatively investigated to study the roles of meso- and micropores. There is a division of functions between micro- and mesopores, with micropores being the main VOC adsorption sites and mesopores greatly enhancing VOC diffusion and adsorbent reusability. On the one hand, micropores should be preserved as much as possible because obtaining mesopores by sacrificing micropores (i.e., alkali treatment) results in 28-60% decreases in adsorption capacities. On the other hand, mesopore introduction is highly desirable, which results in an enhancement of VOC intraparticle diffusion rates by 1.3-2.3 times (at the VOC concentration of 600 ppm) and chlorobenzene adsorption capacity on the 20th cycle increasing from 78% of the initial value to 89 and 93%. The findings may provide valuable information about zeolite-based adsorbents for adsorption removal or recovery of VOCs.

Textile sorption and release of odorous volatile organic compounds from a synthetic sweat solution

Textile sorption and release of odorous volatile organic compounds from a synthetic sweat solution

Thermodynamics of Sorption of Organic Compounds by Sorbents Based on Supramolecular Liquid Crystal HPFAB and β-Cyclodextrin Derivatives under Gas Chromatography Conditions

Thermodynamics of Sorption of Organic Compounds by Sorbents Based on Supramolecular Liquid Crystal HPFAB and β-Cyclodextrin Derivatives under Gas Chromatography Conditions

Minimizing Carbon Dioxide Emissions with Clinoptilolite Zeolite in Moris Pineapple Cultivation on Drained Sapric Soils

Drained tropical peat soils for agriculture emit more carbon dioxide (CO2) into the atmosphere from their stored carbon compared with their pristine state. Field and laboratory experiments were conducted to assess whether the natural zeolite of the clinoptilolite (ZeoC) species could be included in the pineapple fertilization program to decrease the CO2 emissions from tropical sapric soils. The static closed-chamber and laboratory incubation methods were used to determine the effects of ZeoC on the CO2 emitted from a drained sapric soil planted with Moris pineapple. The treatments assessed were as follows: (a) suggested ratio of ZeoC (5 g, 10 g, 14 g, and 20 g of ZeoC) and 20 g compound NPK 30:1:32 fertilizer, enumerated based on the pineapple plant requirement; (b) 20 g of compound NPK 30:1:32 fertilizer only; and (c) unfertilized sapric soils. The drained sapric soils amended with ZeoC (rate of 5 g to 20 g/plant) minimized the CO2 emissions compared with those without the ZeoC, because of the physical and chemical sorption of organic compounds and polar CO2 onto the lattices of ZeoC, which inhibited organic matter decomposition. ZeoC fertilization reduces sapric soil acidity and improves Moris pineapple fruit quality attributes and yield. Monthly pineapple fertilization with ZeoC at the vegetative and flowering phases is an alternative agronomic strategy to reduce CO2 emissions. This approach does not reduce pineapple yield on drained tropical sapric soils.

Thermodynamics of Sorption of Organic Compounds by Sorbents Based on Supramolecular Liquid Crystal HPFAB and β-Cyclodextrin Derivatives under Gas Chromatography Conditions

Using gas chromatography, we studied the influence of the nature of substituents in the β-cyclodextrin (CD) molecule on the sorption properties and the possibility of complex formation with the macrocycle of 26 organic compounds (hydrocarbons and alcohols) in binary sorbents based on the smectic–nematic supramolecular liquid crystal 4-(3-hydroxypropyloxy)-4'-formylazobenzene (HPOFAB) and four derivatives β-CD. It has been established that the nature of the substituents in the β-CD molecule significantly affects the manifestation of solvation interactions between LC and macrocyclic additive and, as a consequence, the mesomorphic, sorption, and selective properties of the studied composite sorbents.

Is sorption technology fit for the removal of persistent and mobile organic contaminants from water?

Persistent, Mobile, and Toxic (PMT) and very persistent and very mobile (vPvM) substances are a growing threat to water security and safety. Many of these substances are distinctively different from other more traditional contaminants in terms of their charge, polarity, and aromaticity. This results in distinctively different sorption affinities towards traditional sorbents such as activated carbon. Additionally, an increasing awareness on the environmental impact and carbon footprint of sorption technologies puts some of the more energy-intensive practices in water treatment into question. Commonly used approaches may thus need to be readjusted to become fit for purpose to remove some of the more challenging PMT and vPvM substances, including for example short chained per- and polyfluoroalkyl substances (PFAS). We here critically review the interactions that drive sorption of organic compounds to activated carbon and related sorbent materials and identify opportunities and limitations of tailoring activated carbon for PMT and vPvM removal. Other less traditional sorbent materials, including ion exchange resins, modified cyclodextrins, zeolites and metal-organic frameworks are then discussed for potential alternative or complementary use in water treatment scenarios. Sorbent regeneration approaches are evaluated in terms of their potential, considering reusability, potential for on-site regeneration, and potential for local production. In this context, we also discuss the benefits of coupling sorption to destructive technologies or to other separation technologies. Finally, we sketch out possible future trends in the evolution of sorption technologies for PMT and vPvM removal from water.

Predictive Model Development for Sorption of Aromatic Organic Compounds by Microplastics

Predictive Model Development for Sorption of Aromatic Organic Compounds by Microplastics

Sorption and Subsequent Chromatographic Determination of Volatile Organic Compounds in Soil Air with the Use of an Exfoliated Graphite-Based Carbon Monolith

Sorption and Subsequent Chromatographic Determination of Volatile Organic Compounds in Soil Air with the Use of an Exfoliated Graphite-Based Carbon Monolith

Adsorption properties and gas chromatographic application of a composite surface-layer sorbent with Terephthalic acid-based metal-organic framework

In this paper, we report on the fabrication of a new material SiO2@MIL-101(Cr), which synthesis is based on the metal-organic framework MIL-101(Cr) and the silica support Chromosorb W. The obtained surface-layer sorbent was analyzed by powder X-ray diffraction analysis, Raman spectroscopy and porosity measurement. The retention regularities and the thermodynamic characteristics of the sorption of volatile organic compounds from the gas phase were studied for the packed column with the surface-layer sorbent SiO2@MIL-101(Cr). The results indicated that the adsorbent-adsorbate interaction in the mesoporous structure of SiO2@MIL-101(Cr) depends not only on the dispersion attractive forces but also on π-π-stacking and specific interactions with hydroxyl groups and metal cations’ open coordination sites on the pore surface. In this work, we gave examples of gas chromatograms of isomers of alkanes, arenes, and chlorine derivatives of methane on a packed column with the obtained sorbent. Examples of gas chromatograms of isomers of alkanes, arenes, and chlorine derivatives of methane on a packed column with the obtained sorbent are presented.

A Novel Analytical Approach to Assessing Sorption of Trace Organic Compounds into Micro- and Nanoplastic Particles.

Assessing the sorption of trace organic compounds (TOrCs) into micro- and nanoplastic particles has traditionally been performed using an aqueous phase analysis or solvent extractions from the particle. Using thermal extraction/desorption–gas chromatography/mass spectrometry (TD-Pyr-GC/MS) offers a possibility to analyze the TOrCs directly from the particle without a long sample preparation. In this study, a combination of two analytical methods is demonstrated. First, the aqueous phase is quantified for TOrC concentrations using Gerstel Twister® and TD-GC/MS. Subsequently, the TOrCs on the particles are analyzed. Different polymer types and sizes (polymethyl methacrylate (PMMA), 48 µm; polyethylene (PE), 48 µm; polystyrene (PS), 41 µm; and PS, 78 nm) were analyzed for three selected TOrCs (phenanthrene, triclosan, and α-cypermethrin). The results revealed that, over a period of 48 h, the highest and fastest sorption occurred for PS 78 nm particles. This was confirmed with a theoretical calculation of the particle surface area. It was also shown for the first time that direct quantification of TOrCs from PS 78 nm nanoparticles is possible. Furthermore, in a mixed solute solution, the three selected TOrCs were sorbed onto the particles simultaneously.

Evaluation of Physical and Chemical Properties of Residue from Gasification of Biomass Wastes

Thermochemical conversion of biomass waste is a high potential option for increasing usage of renewable energy sources and transferring wastes into the circular economy. This work focuses on the evaluation of the energetic and adsorption properties of solid residue (char) of the gasification process. Gasification experiments of biomass wastes (wheat straw, hay and pine sawdust) were carried out in a vertical fixed bed reactor, under a CO2 atmosphere and at various temperatures (800, 900 and 1000 °C). The analysis of the energy properties of the obtained chars included elemental and thermogravimetric (TGA) analysis. TGA results indicated that the chars have properties similar to those of coal; subjected data were used to calculate key combustion parameters. As part of the analysis of adsorption properties, BET, SEM, FTIR and dynamic methanol vapor sorption tests were conducted. The specific surface area has risen from 0.42–1.91 m2/g (biomass) to 419–891 m2/g (char). FTIR spectroscopy confirmed the influence of gasification on the decomposition of characteristic chemical compounds for biomass. Methanol sorption has revealed for the 900 °C chars of pine sawdust the highest sorption capacity and its mass change was 24.15% at P/P0 = 90%. Selected chars might be an appropriate material for volatile organic compounds sorption.

Co-transport of water and p-xylene through carbon molecular sieve membranes

Carbon molecular sieve (CMS) materials are a potential candidate for scalable and high-performance reverse osmosis membranes due to their impressive chemical and thermal stabilities. Moreover, they have the potential to enable impressive rejections of small neutral solutes from water based on their known ability to separate small organic molecules. CMS has been extensively examined for gas and organic solvent separations, but the transport of organic and aqueous mixtures through CMS microstructures is poorly understood. In this work, we investigated the sorption, diffusion, and permeation behavior of organic compounds and water in poly(vinylidene fluoride)(PVDF)-derived CMS (PVDF-CMS). Experimental observations of diffusion, sorption, and permeation shows how the properties of penetrants such as polarity and molecular size affect the transport rates and selectivity. These basic transport and sorption parameters are utilized in sorption-diffusion models to permeation rates of water-organic mixtures in CMS membranes. The transport of water and p-xylene in CMS was experimentally confirmed to follow the sorption-diffusion mechanism. The sorption-diffusion model ideal permselectivity indicates that the CMS is p-xylene selective over water. Water/p-xylene mixture permeation experiments revealed an increased selectivity of p-xylene over water, thus providing tentative evidence for a competitive sorption-selective separation mechanism. This work suggests that CMS membranes exhibit organic-permeable separation properties in water/organic separations. The results presented here highlight the potential for the removal of dilute organics in water via CMS pervaporation membranes.

Sorption and Mobility of Charged Organic Compounds: How to Confront and Overcome Limitations in Their Assessment.

Permanently charged and ionizable organic compounds (IOC) are a large and diverse group of compounds belonging to many contaminant classes, including pharmaceuticals, pesticides, industrial chemicals, and natural toxins. Sorption and mobility of IOCs are distinctively different from those of neutral compounds. Due to electrostatic interactions with natural sorbents, existing concepts for describing neutral organic contaminant sorption, and by extension mobility, are inadequate for IOC. Predictive models developed for neutral compounds are based on octanol–water partitioning of compounds (Kow) and organic-carbon content of soil/sediment, which is used to normalize sorption measurements (KOC). We revisit those concepts and their translation to IOC (Dow and DOC) and discuss compound and soil properties determining sorption of IOC under water saturated conditions. Highlighting possible complementary and/or alternative approaches to better assess IOC mobility, we discuss implications on their regulation and risk assessment. The development of better models for IOC mobility needs consistent and reliable sorption measurements at well-defined chemical conditions in natural porewater, better IOC-, as well as sorbent characterization. Such models should be complemented by monitoring data from the natural environment. The state of knowledge presented here may guide urgently needed future investigations in this field for researchers, engineers, and regulators.

Nanoporous-Crystalline Poly(2,6-dimethyl-1,4-phenylene)oxide Aerogels with Selectively Sulfonated Amorphous Phase for Fast VOC Sorption from Water.

This paper describes the preparation and characterization of poly(2,6-dimethyl-1,4-phenylene)oxide (PPO) highly porous monolithic aerogels with a hydrophobic nanoporous–crystalline phase and a hydrophilic sulfonated amorphous phase. The sulfonated aerogels were obtained by the sulfonation of PPO physical gels, followed by the supercritical CO2 extraction of solvents. WAXD and FTIR analysis showed that the nanoporous–crystalline phase was preserved for a degree of sulfonation up to c.a. 35%, allowing a highly volatile organic compound (VOC) sorption capacity. The sulfonated PPO aerogels exhibited a high water sorption capacity, with a water uptake of up to 500 wt%, and faster VOC sorption kinetics from water with respect to unsulfonated aerogels.

Microwave biochars produced with activated carbon catalyst: Characterization and sorption of volatile organic compounds (VOCs)

A series of microwave biochars derived from wheat straw in the presence of a granulated activated carbon (GAC) catalyst, using a range of microwave conditions, were produced, characterized and tested as sorbents of three benzene series volatile organic compounds (VOCs). The microwave biochar with the greatest specific surface area (SSA), total pore volume (TPV), and micropore volume (312.62 m2 g−1, 0.2218 cm3 g−1, and 0.1380 cm3 g−1, respectively), were produced with 1:3 biomass:GAC catalyst mass ratio, 10 min microwave irradiation time, and at 500 W power level (WB500). Maximum adsorption capacities of WB500 to benzene, toluene and o-xylene were 53.9 mg g−1, 75.8 mg g−1 and 63.0 mg g−1, respectively, and were directly correlated to microwave biochar properties such as SSA, TPV or micropore volume, but were also influenced by VOC properties such as molecular polarity and boiling point. Kinetic modeling suggested that adsorption was governed by both physical partitioning and chemisorption mechanisms. In addition, microwave biochars maintained 79% to 92% of their initial adsorption capacity after ten adsorption/desorption cycles. These results suggest that microwave biochars produced with an GAC catalyst have excellent potential for efficient use in the removal of VOCs from waste gas.

MIL-100(Fe)/Diatomite Composite with Hierarchical Porous Structure for Sorption of Volatile Organic Compounds

MIL-100(Fe)/Diatomite Composite with Hierarchical Porous Structure for Sorption of Volatile Organic Compounds

Application of carbon monolith based on exfoliated graphite for sorption and subsequent chromatographic determination of volatile organic compounds in soil air

The possibility of using a new graphene-based carbon monolith for searching new oil deposits or branches adjacent to the already registered oilfields by areal geochemical survey is demonstrated. The material has been developed at the Faculty of Chemistry of M. V. Lomonosov Moscow State University. Sorption of volatile organic compounds (VOCs) from soil air at the oilfield was carried out using two sorbents (carbon adsorbent and Tenax-TA traditionally used for such analyses) with subsequent determination by gas chromatography with mass spectrometric detection and thermal desorption as a way of sample injection (TD/GC/MS). The new material absorbs more hydrocarbons (n-alkanes and monoaromatics) in the range from C8 to C16 than Tenax-TA, the intensities of the chromatographic peaks of the compounds also being higher. The phenomenon of irreversible sorption from carbon materials is observed for VOCs from C17 and more. However, the concentration of such substances in the soil air is rather low due to the low pressure of saturated vapors of these compounds under normal conditions. Hence, the chromatogram of carbon monolith reflects the macro-characteristics of this oil deposit better than Tenax-TA. To increase the sensitivity of the determination, a preliminary optimization of thermal desorption conditions was carried out. The values of the helium flow rate through the sorbent sample and the desorption time of the compounds are chosen to get the largest peak area. The regeneration of sorbent samples is carried out to provide the possibility of their reusage. Tenax-TA decomposes at lower temperatures compared to carbon sorbent and thus cannot be purified completely unlike the new monolith. The graphene-based sorbent is reusable and much cheaper in the manufacture than imported polymer Tenax-TA since it is made of domestic materials.

Changes in Adsorption Characteristics of Heavy Metals and Organic Pollutants Following Pyrolytic Treatment of Petroleum-Contaminated Dredged Sediment

Objectives : This study investigated the changes in adsorption characteristics of dredged sediment for heavy metals and organic pollutants after petroleum contamination followed by pyrolytic treatment.Methods : Pyrolytic treatment was conducted at two heating temperatures, 300℃ and 500℃, for 30 min using muffle furnace. Sediment spiked with No. 6 Fuel Oil at initial total petroleum hydrocarbon (TPH) concentrations of 5,000-50,000 mg/kg was used. Sorption experiments were conducted for heavy metals (Cd, Cu, Pb, Zn, Ni, Hg, As, Cr), phenanthrene and bisphenol A using clean sediment (sediment before the petroleum spiking) and pyrolyzed sediment.Results and Discussion : Pyrolytic treatment at 500℃ showed excellent TPH removal efficiency, resulting in the residual concentration of less than 50 mg/kg for all initial TPH contamination levels. High efficiencies (> 98%) were observed for the sorptive removal of Cu, Zn and Pb in the aqueous phase for both the two sediments. The removal efficiencies of Ni and Cd from the aqueous phase using pyrolyzed sediment were 31% and 24% lower than those using clean sediment, respectively, due to the reduced oxygen-containing functional group content and specific surface area after the pyrolytic treatment. The sediment-water distribution coefficient (Kd) and sediment organic carbon-water distribution coefficient (Koc) values of bisphenol A and phenanthrene in pyrolyzed sediment were considerably higher than in clean sediment due to the high organic compound sorption affinity exhibited by carbonaceous matter that was generated during the pyrolytic sediment treatment.Conclusions : The capability of pyrolytic treatment of dredged sediment to notably improve its organic compound sorption capacity may be exploited for beneficial use of the treatment product. The product may be applied as fill and backfill, soil amendment, or in-situ sediment capping materials in highly industrialized areas where mitigation measures for organic contaminant migration are necessary.