Effective Sorbent Research Articles

Stability of CO2 Capture by Lithium Orthosilicate Under Various Conditions and the Presence of SO2

Investigating effective sorbent materials in the CO2 sorption process is crucial. Lithium-based sorbents combine high carbon capture efficiency with excellent mechanical stability. Lithium orthosilicate (Li4SiO4) was prepared for the CO2 capture test in this study with a variety of variables, including the sorbent calcination temperature, space velocity, operation temperature, and water vapor and SO2 concentrations. Several analyses were used in the characterization of the spent and fresh sorbents. Additionally, the CO2 sorption reaction kinetics were investigated using deactivation models. The sorbent with the best utilization value was obtained via calcining Li4SiO4 at 700 °C for five hours. Li4SiO4 demonstrated exceptional stability in the 600–800 °C temperature and 1200–6000 mL/h/g space velocity ranges. The performance of the sorbent was not significantly affected by the water vapor content up to 10%. Nevertheless, further increasing the water vapor stream drastically declined its performance due to water masking on the sorbent’s surface. Similar sorption trends were demonstrated by Li4SiO4 in all SO2 content setups. The Type I deactivation model was well fitted to the experimental data.

Sodium aluminosilicate synthesised from rice straw as a sorption barrier to protect soil from antimony contamination

ABSTRACT A novel effective sorbent for the extraction of antimony(III) from rice straw has been generated, having a specific surface area of 470 m²/g. The material was subjected to a series of analyses, including scanning electron microscopy, energy dispersive X-ray analysis, X-ray diffraction analysis, and FT-IR spectroscopy. The sorption properties relative to Sb(III) ions were characterised in dynamic conditions in a column experiment. The total dynamic exchange sorption capacity of 113.92 mg/g renders this material suitable for use as a permeable reactive barrier (sorption barrier) with the objective of protecting soils from antimony contamination. To identify the optimal conditions for soil protection, the chemical composition, acid-base properties, and sorption parameters of soils of varying types were characterised. The sorption properties of the soils were determined in static conditions to obtain the sorption isotherm. The maximal sorption capacity was identified for the soil sample with low base saturation and a high organic component content, a finding that was corroborated by DTA analysis. The results of the column experiment with layers of soil and aluminosilicate sorbent indicate the promising use of the new sorbent as a sorption barrier for the effective protection of soils from antimony contamination.

The effect of cross-linking agent amount and type on the sorption properties of starch graft polyacrylamide and poly(acrylic acid) copolymers

Abstract In free radical polymerization initiated by 2,2’-azobis(2-methylpropionamidine) dihydrochloride, grafted starch copolymers with a weight ratio of acrylamide to acrylic acid of 1:2 were obtained. Three acrylic products were used to cross-linking starch copolymers: MBA, PETIA and EBECRYL 40 in amounts of: 0.2, 0.4, 0.6 and 1.0 wt.%. Materials were characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry and reoviscometry. The sorption properties of starch copolymers were confirmed by sorption tests: water absorption, swelling in water and sorption of cations: trivalent iron and divalent copper. The highest water absorption is characteristic of materials cross-linked with MBA (1800%), then PETIA (1400%) and EBECRYL 40 (850%). On the other hand, the best swelling results are in the sequence PETIA > MBA > EBECRYL (1050% > 900% > 570%). The most effective sorbent of cations is the copolymer cross-linked with MBA. Solution purifications of 90% and 45% were obtained for Fe+3 and Cu+2, respectively.

Sodium cation exchanged zeolites for direct air capture of CO2

Direct air capture technology requires investigating materials that can capture carbon dioxide inexpensively and efficiently, considering their performance under real atmospheric conditions. This study systematically investigated the CO2 adsorption-desorption performance of the representative zeolites (ZSM-5, Beta, Mordenite and Y) in H- and Na-forms using various analytical methods, including in-situ Diffuse Reflectance Infrared Fourier Transform spectroscopy. Compared to the corresponding H-zeolites, the enhancement of CO2 adsorption capacity by Na+ ions was observed for all the structure-type zeolite adsorbents. The Na-ZSM-5 showed excellent performance in the direct air capture of CO2 (DAC) due to its relatively smaller pore size and stronger acid-basic properties. The effective adsorption capacity of Na-ZSM-5 was pronounced at lower Si/Al ratios, making it the most efficient low-concentration CO2 adsorbent. The low silica Na-ZSM-5 exhibited a durable adsorption-desorption capacity after multiple cycles, indicating its practical reusability. When applied to real atmospheric air conditions, this low silica Na-ZSM-5 effectively adsorbed CO2 in the presence of oxygen and moisture, emphasizing its potential for a direct air capture adsorbent. This study provides insights into the properties of zeolites for CO2 capture from air, highlighting their potential as effective DAC sorbents that can be produced on a large scale.

Chankanai Zeolite Modified with Heteroatomic Derivatives of 3-Aminopropyltriethoxysilane as an Effective Sorbent for Ag(I), Co(II)

Bis-N,N-(3-triethoxysilylpropyl)thiosemicarbazide 3 was obtained by the condensation of 3-aminopropyltriethoxysilane 1 with thiosemicarbazide 2. Ethyl ether N-[3-(triethoxysilyl)propyl]-b-alanine 5 was obtained by the interaction of an equimolar amount of aminopropyltriethoxysilane 1 and ethyl acrylate 4 (aza-Michael reaction). Synthesized functional organosilanes 3 and 5 were successfully immobilized on the surface of natural zeolite Z (Chankanai deposit, Kazakhstan). Compounds and materials have been studied by NMR and IR Fourier spectroscopy and X-ray diffraction analysis. The elemental composition and morphology of modified zeolites Z3 and Z5 were studied using SEM-EDX analysis. The modification of zeolite by organosilanes 3 and 5 leads to changes in the surface structure of the material: with the enlargement of particles and agglomerates, the surface becomes more homogeneous and less porous. This indicates a high degree of zeolite coverage by the modifier layer. The study of the sorption characteristics of the initial Z and modified zeolites (Z3 and Z5) showed a high sorption capacity relative to Ag(I) and Co(II) (static sorption capacity, SSC = 35.85–23.92 mg/g), whereas the SSC values for Z were SSC = 20.63 and 16.64 mg/g. The adsorption of Ag(I) and Co(II) ions was studied in solutions prepared using Co(NO3)2·6H2O, AgNO3 and distilled water. The choice of the initial concentration of metal ions, as well as the pH of the solutions, corresponded to the composition of wastewater from real electroplating production. Zeolites Z3 and Z5 can be used in various sectors of industry, in ecology and for medical purposes as inexpensive and effective adsorbents (enterosorbents) of heavy and noble metals.

Engineered Mg-modified biochar-based sorbent for arsenic separation and pre-concentration

The utilization of biochar as a relatively efficient sorbent or stationary phase for the separation and preconcentration of a wide range of analytes represents an innovative approach in current sample pretreatment methods. Appropriate pre- and post-pyrolysis modification of the input precursor and pyrolysis product, respectively, allows targeted design of the physicochemical properties and sorption characteristics of the resulting sorbent. The present work deals with the preparation of pyrolysis materials based on unmodified cattail leaf biomass (BC) and its Mg-modified analogue (MgBC) by a slow pyrolysis process at 500 °C and a residence time of 1 h in a pyrolysis reactor. Physicochemical characterization of BC and MgBC carried out by pH, total C, N, surface size analysis (SSA), 13C NMR, SEM-EDX and XRD confirmed significant morphological and mineralogical differences between the prepared sorbents. By performing sorption experiments using a model anionic analyte (As) and application of Langmuir isotherm, we found that the predicted maximum sorption capacity of MgBC for As is 13.5-fold higher than that of BC. The sorption process of As by both sorbents is best described by the Sips adsorption isotherm (R2 ≥ 0.995) and a pseudo-nth order kinetic model (R2 ≥ 0.997). The optimum pH for As sorption by BC and MgBC sorbents is in the interval 5–6. The presence of competitive phosphate anions (equimolar concentration of 1:1) in the solution significantly reduces the sorption capacity of MgBC for As by 40% for BC by 70%. The presence of Cl- ions showed no significant effect on the sorption capacity of Bc and MgBC for As. Both sorbents were best recovered using 0.1 mol/L NaOH solution when the desorption efficiency for both sorbents was more than 95%. The MgBC sorbent showed 35% retention of As from the real sample in the model SPE column at a flow rate of 0.12 mL/s. Based on the obtained knowledge, it is evident that biochar-based sorbent prepared from Mg-modified precursor represents an effective sorbent for anionic forms of analytes and opens the possibility of its use also in preconcentration and separation techniques.

Separation and enrichment of Cd and Pb from food and water samples based on a graphene oxide-decorated poly 2-diethylaminoethyl methacrylate nanocomposite by dispersive micro-solid phase extraction (d-μ-SPE)

In this study, a graphene oxide combined with poly(2-diethylaminoethyl methacrylate) (GO@PDEAEMA) nanocomposite was synthesized for the separation and enrichment of Cd and Pb from food and water samples using the dispersive micro-solid phase extraction (d-μ-SPE) technique. The GO@PDEAEMA nanocomposite was synthesized using surface-initiated atom transfer radical polymerization (SI-ATRP) and characterized using various analytical techniques, such as FTIR, FE-SEM, TGA, BET, and XRD. The optimal experimental conditions were pH 8, 0.5 M HNO₃ as eluent, 5 mg of sorbent, and adsorption/desorption times of 0.5 and 1 min, respectively, with a recovery range of 89–101 %. The suggested method showed low limits of detection (LOD) and quantification (LOQ) of 0.11 μg L−1 and 0.37 μg L−1 for Cd and 0.28 μg L−1 and 0.93 μg L−1 for Pb, respectively. The optimal procedure was successfully applied to real water and food samples. The study demonstrates the possibility of using GO@PDEAEMA nanocomposite as an effective sorbent for toxic metal extraction.

Fe oxide modification of yerba mate waste-derived biochar and activated biochar via three methodologies: Effects of material surface properties on the Fe oxides grown and implications for paracetamol and atenolol sorption

This work presents, for the first time, the development of magnetic composites using activated biochar (BC-Act) derived from yerba mate waste. It includes an analysis of the effect of the activation process on the formation of iron oxides using the most applied methodologies, an aspect that has not been studied before. Three methodologies have been considered for Fe oxides grown: coprecipitation (COP), impregnation-pyrolysis (IP), and alkaline oxidation in the presence of nitrates (AOPN). The materials with magnetic response and good enough BET area have been used to sorb Paracetamol (PCT) and Atenolol (ATE) from aqueous solutions. The activation process has resulted in the formation of mesopores, an increase of surface area due to the destruction/release of impurities, the transformation of whewellite to calcite, and changes in magnetic behavior. These changes seem to affect the formation of Fe oxides. The COP and IP methods allow the development of magnetic composites based on BC-Act, BC-Act-COP and BC-Act-IP, with saturation magnetization of 3.1 Am2/kg and 1.5 Am2/kg, respectively, attributed to magnetite/maghemite formation and a minimal distance for manipulation by a magnetic field of 12.1 mm and 7.9 mm, respectively. These distances must be considered when developing efficient removal systems using magnetic composites. PCT was sorbed faster and more efficiently than ATE, associated with its smaller molecular size. This presents a valuable contribution to environmental sustainability and advancements in water purification, highlighting the dual advantage of converting the widely available waste product, predominantly found in South America, into an effective sorbent with magnetic characteristics, capable of removing pharmaceutical contaminants from aqueous solutions. This is done in the circular economy, avoiding the final deposition of yerba mate waste in landfills, increasing their lifespan, and safeguarding other natural and non-renewable resources, such as clays, whose preservation rather than exploitation improves environmental quality and saves energy.

Enhancing Analytical Potential for Ultratrace Analysis of Inorganic Oxyanions Using Extraction Procedures with Layered Double Hydroxides.

This article provides an overview of the use of layered double hydroxides (LDHs) as effective sorbents in various extraction methods, including column-based solid-phase extraction (SPE), dispersive solid-phase extraction (DSPE), and magnetic solid-phase extraction (MSPE), for the separation and preconcentration of inorganic oxyanions of chromium, arsenic, and selenium. The primary focus is on enhancing the analytical performance of spectrometric detection techniques, particularly in terms of sensitivity and selectivity when analyzing low concentrations of target analytes in complex matrices. LDHs, which can be readily prepared and structurally modified with various substances, offer promising potential for the development of novel analytical methods. When used in analytical extraction procedures and following careful optimization of experimental conditions, the developed methods have yielded satisfactory results, as documented by studies reviewed in this paper. This review is intended to assist analytical chemists in scientific laboratories involved in developing new extraction procedures.

Stationary and Dynamic Sorption of 141Ce(III) and 152+154Eu(III) Using Alginate–Gypsum Bio-composite Beads

AbstractThis study introduces a novel Alginate–Gypsum bio-composite, synthesized at a 2:1 weight ratio, as an effective sorbent for Eu(III) and Ce(III) ions in aqueous solutions. Optimal conditions (pH 3, 5-h contact time) yielded 98% sorption efficiency for both ions in single batch systems (50 mg L−1, 20 °C). In binary systems, the composite adsorbed 33.04% of Ce(III) and 47.26% of Eu(III) (mg L−1, 20 °C). Dynamic column system showed 80.297% Ce(III) and 77.5% Eu(III) sorption. The process was endothermic, spontaneous, and best described by a quasi-nth order kinetic model. The sorption process was best described by the quasi-nth order kinetic model, with Eu(III) sorption aligning with the Langmuir and Sips models, and Ce(III) sorption following the Redlich–Peterson and Sips models. Desorption was highly efficient, with up to 99% for Eu(III) and 97% for Ce(III) using 0.1 M EDTA.

Removal of Dyes from Waste Water Using Low‐Cost Adsorbents

AbstractThe principal objective of this article is a thorough analysis of the usage of inexpensive adsorbents to eliminate dyes from different aquatic environments. Dyes, commonly employed in industries—textiles, pharmaceuticals, and food, pose a significant environmental concern due to their persistence and potential toxicity. In response, researchers have explored the efficacy of low‐cost adsorbents (LCAs) as sustainable and economical alternatives for dye elimination. An overview of the environmental effects of dye contamination and the difficulties in using traditional dye removal techniques is given at the outset of the paper. It then delves into the diverse range of LCAs, including agricultural by‐products, waste materials, and natural substances, that have shown promise in adsorbing and eliminating dye contaminants. Examples of such adsorbents include activated carbon (AC) derived from agricultural residues, bio‐adsorbents from various plant materials, and industrial by‐products with inherent adsorption properties. Key mechanisms involved in the adsorption process, such as surface chemistry, pore structure, and electrostatic interactions, are elucidated to offer a fundamental understanding of the sorption capabilities of these materials. This comprehensive review consolidates the current knowledge on dye removal utilizing LCAs, offering insights into the challenges, advancements, and future directions in this environmentally significant field. The findings underscore the potential of harnessing readily available, sustainable materials as effective sorbents for mitigating the adverse impacts of dye pollutants in aqueous systems. The adsorption capacity is comparable to supplementary adsorbents suggested for the removal of dyes. The widely accessible adsorption properties of basic and acidic dyes do not significantly differ from one another.

Removal of Lead Cations by Novel Organoclays Derived from Bentonite and Amphoteric and Nonionic Surfactants.

For many decades, natural and modified clay minerals have been used as adsorbents to clean up aquatic and soil ecosystems contaminated with organic and inorganic pollutants. In this study, organoclays based on bentonite and various amphoteric and nonionic surfactants were synthesized and tested as effective sorbents for lead ions. The maximum values of R were obtained when describing the sorption processes using the Langmuir model, which ranged from 0.97 to 0.99. The adsorption of lead ions by these organoclays was investigated using different sorption models including the Langmuir, Freundlich, and BET. It was found that, according to the values of limiting adsorption to the Langmuir equation, the synthesized organoclays formed an increasing series: organoclay with cocamide diethanolamine < bentonite < organoclay with lauramine oxide < organoclay with sodium cocoiminodipropionate < organoclay with disodium cocoamphodiacetate < organoclay with alkyl polyglucoside. The Gibbs energy for all of the analyzed samples was calculated and found to be negative, indicating the spontaneity of the cation adsorption process in the forward direction. The maximum value of the adsorption capacity of lead cations on organoclay-based bentonite with alkyl polyglucoside was 1.49 ± 0.05 mmol/g according to the Langmuir model, and 0.523 ± 0.003 mmol/g as determined by the BET model. In the process of modifying bentonite, there was an increase in negative values of the zeta potential for organoclays compared to the initial mineral, which clearly enhanced their electrostatic interactions with the positively charged lead ions. It was hypothesized, based on the physicochemical principles, that exchange adsorption is the main mechanism for lead absorption. Based on chemical approaches, organoclays based on amphoteric surfactants absorb lead mainly through the mechanisms of electrostatic attraction, ion exchange, and complexation as well as the formation of insoluble precipitates. Organoclays based on nonionic surfactants, on the other hand, absorb lead through mechanisms of complexation (including chelation) and the formation of insoluble chemical precipitates. The comparison of isotherms from different models allows us to find the most accurate match between the model and the experimental data, and to better understand the nature of the processes involved.

STUDY OF METHODS FOR ACTIVATING BENTONITE CLAY FROM THE DARBAZA DEPOSIT

In our country, the problem of water treatment remains urgent, and this is facilitated by the growth of external factors, which can include the increase in the number of industrial enterprises, agricultural development, urban growth and others. Objective. To solve the problem of wastewater treatment it is economically advantageous to create new sorbents, from the resources available in our country. Instrumental test methods were chosen for bentonite clay treatment under experimental conditions using scanning electron microscope (SEM) Jeol JSM-6490l V, FTIR spectrometer NEXUS E.S.P. (Thermo Scientific, USA), laser particle size analyser Analizette 22 MicroTec (Fritsch GmbH, Germany). According to the results of instrumental studies, the elemental and mineralogical composition of bentonite clay from Darbazi deposit was determined using scanning scanning electron microscope and FTIR spectrometer. The obtained sorbent on the basis of bentonite clay has a high sorption capacity and is recommended to be used in wastewater treatment of chemical industries. The obtained sorbent on the basis of bentonite clay from Darbazinsky deposit allows to purify wastewater of various productions containing ions of heavy metals up to 95%. The developed sorbent on the basis of bentonite clay has ecological and economic efficiency, connection with the use of local natural resources. Thus, it should be noted that for adsorptive treatment of wastewater from chemical industries with a high degree it is possible to use effective sorbents based on bentonite clays of Darbaza deposit. It should also be noted that the use of bentonite clays for water treatment by sorption process is an effective and affordable alternative to adsorbents, which show high adsorption capacity in relation to various compounds.

Greener analysis of eleven basic drugs in blood and urine using carbowax 20M based biofluid sampler (BFS) device

For the first time, a novel biofluid sampler (BFS) and sample preparation device is applied for the analysis of 11 basic drugs (i.e., pheniramine, chlorpheniramine, fluoxetine, tramadol, amitriptyline, ketamine, diazepam, chlordiazepoxide, clozapine, chlorpromazine, dothiepin) in biological matrices (i.e., blood and urine). BFS utilizes advanced, highly effective sorbents derived from sol-gel sorbent coating technology onto cellulose fabric substrate, improving sample collection and retention. BFS has the capability to retain a biological sample from 10 to 1000 µL without requiring any dilution or pre-treatment of the sample. The biological samples were pipetted onto the BFS device and dried at room temperature. Subsequently, adsorbed analytes were back-extracted into 1000 µL of methanol without requiring any imposed external diffusion process and then analyzed by gas chromatography-mass spectrometry (GC-MS). A one-factor-at-a-time (OFAT) screening procedure was used to extensively screen and optimize several parameters, including sample volume, elution time, solvent volume, and solvent type. Under the optimal conditions of the study, the method was found to be linear within the range 0.1–10 µg mL−1 for both blood and urine. Quantification limits were established for blood samples within the range of 0.072–0.095 μg mL−1 and for urine samples within the range of 0.050–0.069 μg mL−1. The precisions within and between days were less than 7% and 10%, respectively. The target analytes showed good recoveries utilizing the recommended protocol, with ranges of 45.1%–103.4%. Furthermore, the methodology has been effectively implemented in forensic toxicology case work. Moreover, the green characteristics and applicability of the suggested methodology was evaluated using softwares i.e., AGREE and BAGI.

Removal of aflatoxin M1 in milk using magnetic laccase/MoS2/chitosan nanocomposite as an efficient sorbent

The current study tries to find the impact of the integration of laccase enzyme (Lac) onto magnetized chitosan (Cs) nanoparticles composed of molybdenum disulfide (MoS2 NPs) (Fe3O4/Cs/MoS2/Lac NPs) on the removal of AFM1 in milk samples. The Fe3O4/Cs/MoS2/Lac NPs were characterized by FT-IR, XRD, BET, TEM, FESEM, EDS, PSA, and VSM analysis. The cytotoxic activity of the synthesized nanoparticles in different concentrations was evaluated using the MTT method. The results show that the synthesized nanoparticles don't have cytotoxic activity at concentrations less than 20 mg/l. The ability of the prepared nanoparticles to remove AFM1 was compared by bare laccase enzyme, MoS2, and Fe3O4/Cs/MoS2 composite, indicating that the Fe3O4/Cs/MoS2/Lac NPs the highest adsorption efficiency toward AFM1. Besides, the immobilization efficiency of laccase with a concentration range of 0.5–2.0 was investigated, indicating that the highest activity recovery of 96.8% was obtained using 2 mg/ml laccase loading capacity. The highest removal percentage of AFM1 (68.5%) in the milk samples was obtained by the Fe3O4/Cs/MoS2/Lac NPs at a contact time of 1 h. As a result, Fe3O4/MoS2/Cs/Lac NPs can potentially be utilized as an effective sorbent with high capacity and selectivity to remove AFM1 from milk samples.

Constructing covalent organic frameworks with dense thiophene S sites for effective iodine capture

Developing versatile sorption materials for radionuclide capture (e.g. iodine) is critical for nuclear energy and environmental science. Covalent organic frameworks (COFs) have recently become a new platform for developing sorption materials because of their high surface area and functionalised skeleton structure. Herein, two types of COF materials containing thiophene were designed as iodine sorbents and synthesised via a Schiff base reaction of benzo[1,2-b:3,4-b’:5,6-b’’]trithiophene-2,5,8-tricarbaldehyde, benzidine (DADP) and p-phenylenediamine (DAB): DADP-COF and DAB-COF. DAB-COF exhibits a unique granular-rod-like morphology and has a higher surface area (1775 m2/g) than DADP-COF (1140 m2/g), which is clearly beneficial for the physical adsorption of iodine. Meanwhile, the COF backbone is rich in N and S sites, which are advantageous for the chemical adsorption of iodine. These two features make the two prepared COFs ideal iodine sorption materials. DAB-COF demonstrates an excellent gaseous iodine adsorption capacity of 4.2 g/g, ranking it as one of the most effective iodine sorption materials, while DADP-COF exhibits a good adsorption capacity of over 235 mg/g for iodine in cyclohexane solutions. Density functional theory calculations prove that imine N and thiophene S serve as active sites during the iodine adsorption. DAB-COF exposes more active sites because of its higher surface area, leading to a higher iodine adsorption capacity than DADP-COF. The results of this study indicate that introducing thiophene to COFs improves sorption efficacy for sorption applications in general and particularly paves the way for developing stable and effective COF sorbents for iodine capture from various environments.

Directed Hydrothermal Synthesis of Aluminosilicates of Various Structural Types and Prospects for Their Use in Medicine

The results of analysis and experimental studies of the possibilities of using synthetic aluminosilicates (montmorillonites, kaolinites, zeolites) in medicine, in particular in the field of entero- and hemosorption, in the development of targeted drug delivery systems with prolonged and pH-controlled release of the active substance in various environments, as well as components of wound dressings are presented. Montmorillonites, aluminosilicates of the kaolinite subgroup with different particle morphologies and zeolites of structural types Beta, Rho and Y were obtained under hydrothermal conditions and characterized by a complex of physicochemical research methods. The results of studying the adsorption and desorption of model drugs (thiamine hydrochloride, 5-fluorouracil) from porous aluminosilicate matrices of various chemical compositions in various media simulating body environments, adsorption of markers of endogenous intoxication (methylene blue), the ability of aluminosilicates to biodegrade in body environments, and also studies of biological activity, in particular cytotoxicity and hemolytic activity of synthetic aluminosilicates are presented. The results obtained show significant prospects for the use of synthetic aluminosilicates to obtain non-toxic, highly effective sorbents for medical use and drug carriers.

Competing Kinetic Consequences of CO2 on the Oxidative Degradation of Branched Poly(ethylenimine).

Amine-functionalized porous solid materials are effective sorbents for direct air capture (DAC) of CO2. However, they are prone to oxidative degradation in service, increasing the materials cost for widespread implementation. While the identification of oxidation products has given insights into degradation pathways, the roles of some species, like CO2 itself, remain unresolved, with conflicting information in the literature. Here, we investigate the impact of CO2 on the oxidative degradation of poly(ethylenimine)-alumina (PEI/Al2O3) sorbents under conditions encompassing a wide range of CO2-air mixture compositions and temperatures relevant to DAC conditions, thereby reconciling the conflicting data in the literature. Degradation profiles characterized by thermogravimetric analysis, in situ ATR-FTIR, and CO2 capacity measurements reveal nonmonotonic effects of CO2 concentrations and temperatures on oxidation kinetics. Specifically, 0.04% CO2 accelerates PEI/Al2O3 oxidation more at low temperatures (<90 °C) compared to 1% and 5% CO2, but this trend reverses at high temperatures (>90 °C). First-principles metadynamics, machine learning accelerated molecular dynamics simulations, and 1H relaxometry experiments show that chemisorbed CO2 acid-catalyzes critical oxidation reactions, while extensive CO2 uptake reduces PEI branch mobility, slowing radical propagation. These contrasting kinetic effects of CO2 explain the complex degradation profiles observed in this work and in prior literature. Collectively, this work highlights the importance of considering atmospheric components in the design of DAC sorbents and processes. Additionally, it identifies the unconstrained branch mobility and local acid environment as two of the major culprits in the oxidation of amine-based sorbents, suggesting potential strategies to mitigate sorbent degradation.

An insight into the utilization of high-sulfur green Saudi Arabian petcoke as an ecofriendly sorbent for enhanced simultaneous sequestration of heavy metal ions from industrial wastewaters

Developing effective and green sorbents for the sequestration of water pollutants has increased attention to safe and sustainable water generation. This study aimed to discover a new utilization and the ability of green, high-sulfur Saudi Arabian petcoke (SA-PET) for heavy metal ion uptake. The organic sulfur content and aromatic properties of SA-PET allowed for rapid and improved performance against various metal ions via strong complex formation reactions and cation-π interactions. Also, the effects of different analytical factors were carefully studied and optimized. At pH 6–7, the maximum recovery values of PbII, CuII, CdII, ZnII, MnII, NiII and CoII metal ions were 21.09–95.76%. The experimental results demonstrate single-layer adsorption at the binding sites on the petcoke’s surface, and they are in good agreement with the Langmuir model in explaining the adsorption process, which is driven by electrostatic interactions between the petcoke surface and the studied metal ions. The pseudo-second-order kinetics model fits the adsorption data for all the target metal ions well. Furthermore, the outstanding SA-PET's stability allowed for efficient extractions over the course of 10 successive runs with negligible loss in the metal recovery percentage. With extraction recoveries up to 96.6% and a relative standard deviation less than 5%, SA-PET's efficiency in removing the target metal ions from different industrial wastewater samples gives it excellent promise as a novel green sorbent for detoxifying heavy metals from aquatic life. In conclusions, our findings, SA-PET emerged as a viable substitute for traditional synthetic adsorbents of heavy metals, in keeping with the growing trend toward green adsorbents for more sustainable development.

High-performance solid-phase microextraction based on a nanocomposite sorbent of MOF/COF hybrid for ultra-trace analysis of trifluralin in food samples using the ion mobility spectrometer

Two well-known porous hybrid materials, a metal-organic framework (MOF) based on manganese and a melamine-rich covalent organic framework (COF) were combined, resulting in a highly effective nanocomposite sorbent of Mn-terephthalic acid (TA) /COF. After investigating the properties of the synthesized adsorbent, it was finally used as a new fiber for solid-phase microextraction. The method, named high-performance solid-phase microextraction (HPSPME), was utilized for the extraction and ultra-trace analysis of trifluralin in agricultural waters, fruit, and vegetable samples by using corona discharge ionization-ion mobility spectrometer (CD-IMS). To increase the extraction efficiency, experimental parameters including, temperature and time of extraction and desorption, solution pH, and stirring rate were optimized. Considering the optimized conditions, the enrichment factor of 2002, the limit of detection (LOD) 0.08 ng mL−1 (S/N=3), and linear dynamic range (LDR) 0.25–10.00 ng mL−1 with a coefficient of determination (R2=0.9987) were obtained. Relative standard deviations (RSDs, n = 3) of <9.7, <3.5, and <8.9 % were obtained, respectively, for reproducibility of the prepared fibers, intra- and inter-day. The relative recovery values for the real samples were 84–124 %. The proposed method’s accuracy for the sample impregnated with trifluralin was also evaluated by the EPA standard method.