Sorption Features Research Articles

Natural rubber composites reinforced with sodium sulfate waste from pigment industry: A circular economy approach for solid waste management

The massive industrial waste discharged into the environment adversely affects the ecological system. Traditional methods like landfilling or other disposal methods can no longer be adequate to handle them, and their reutilization is consequently gaining popularity. Most chemical industries generate a large amount of sodium sulfate waste (SSW), contaminating air and water. Hence, its reutilization in natural rubber (NR) as a reinforcing filler is explored. SSW generated in Ultramarine and Pigments Ltd., Chennai, India, was procured and characterized. The fabricated NR-SSW composite's cure, mechanical, and sorption features have been investigated. NR composite with 7.5 phr (parts per hundred of rubber) SSW showed a 9 %, 14 % and 29 % increase in tensile strength, tear strength, and modulus at 300 % elongation, respectively, and a remarkable decrease in abrasion loss and higher abrasion resistance index (ARI) as compared to NR-Neat. All these properties decreased beyond 7.5 phr SSW addition, proving its better adhesion on NR up to 7.5 phr loading. The experimental tensile strength showed a good correlation with Turcsányi-Pukànszky-Tüdõs (T-P-T) model, confirming the better matrix-filler interaction up to 7.5 phr SSW loading. Sorption studies proved the better barrier properties of NR-SSW7.5 composite compared to NR-Neat. Various kinetic parameters were studied, and a suitable transportation method was suggested. NR-SSW7.5 composite, having remarkable mechanical and barrier properties, finds application in various rubber products manufacture. The reutilization of SSW as an efficient filler in NR is an innovative attempt from a circular economy perspective, as it reduces production costs and environmental pollution.

Piezoelectric Gas Sensors with Polycomposite Coatings in Biomedical Application

When developing methods for diagnosing pathologies and diseases in humans and animals using electronic noses, one of the important trends is the miniaturization of devices, while maintaining significant information for diagnostic purposes. A combination of several sorbents that have unique sorption features of volatile organic compounds (VOCs) on one transducer is a possible option for the miniaturization of sensors for gas analysis. This paper considers the principles of creating polycomposite coatings on the electrodes of piezoelectric quartz resonators, including the choice of sorbents for the formation of sensitive layers, determining the mass and geometry of the formation of sensitive layers in a polycomposite coating, as well as an algorithm for processing the output data of sensors to obtain maximum information about the qualitative and quantitative composition of the gas phase. A comparative analysis of the efficiency and kinetics of VOC vapor sorption by sensors with polycomposite coatings and a set of sensors with relevant single coatings has been carried out. Regression equations have been obtained to predict the molar-specific sensitivity of the microbalance of VOC vapors by a sensor with a polycomposite coating of three sorbents with an error of 5-15% based on the results of the microbalance of VOC vapors on single coatings. A method for creating "visual prints" of sensor signals with polycomposite coatings is shown, with results comparable to those from an array of sensors. The parameters Aij∑ are proposed for obtaining information on the qualitative composition of the gas phase when processing the output data of sensors with polycomposite coatings. A biochemical study of exhaled breath condensate (EBC) samples, a microbiological investigation of calf tracheal washes, and a clinical examination were conducted to assess the presence of bovine respiratory disease (BRD). An analysis of the gas phase over EBC samples with an array of sensors with polycomposite coatings was also carried out. The "visual prints" of the responses of sensors with polycomposite coatings and the results of the identification of VOCs in the gas phase over EBC samples were compared to the results of bacteriological studies of tracheal washes of the studied calves. A connection was found between the parameters Aij∑ of a group of sensors with polycomposite coatings and the biochemical parameters of biosamples. The adequacy of replacing an array of piezoelectric sensors with single coatings by the sensors with polycomposite coatings is shown.

Formation of the tillage pan bottom horizon in black soils and its sorption features with respect to organic matter and heavy metals

Formation of the tillage pan bottom horizon in black soils and its sorption features with respect to organic matter and heavy metals

High capacity gas capture and selectivity properties of triazatruxene-based ultramicroporous hyper-crosslinked covalent polymer.

Tuning the selective sorption features of microporous organic networks is of great importance for subsequent applications in gas uptake and hiding, while it is more attractive in terms of being both time and cost effective to realize these optimizations without using functional groups in the core and linker. “Knitting” is one of the easiest and most used method to obtain a broad scope of hyper-crosslinked polymers on a large scale from aromatic structures that do not contain functional groups for polymerization. By the use of Knitting method, a hypercrosslinked covalent ultramicroporous organic polymer was obtained via stepwise process from using triazatruxene (TAT) as core -a planar indole trimer- through anhydrous FeCl3 catalyzed Friedel–Crafts alkylation using dimethoxybenzene as a linker. The resulting microporous polymer, namely TATHCCP was completely identified by analytical and spectral techniques after examined for gas properties (CO2, CH4, O2, CO, and H2) and selectivity (CO2/N2, CO2/O2, for CO2/CO and CO2/CH4) up to 1 bar and increased temperatures (273 K, 296 K and 320 K). Although it has a relatively low (Brunauer–Emmett–Teller) BET specific surface area around 557 m2/g, it was seen to have a high CO2 capture capacity approaching 10% wt. at 273 K. In accordance with (ideal adsorbed solution theory) IAST computations, it was revealed that interesting selectivity features hitting up to 60 for CO2/N2, 45 for CO2/O2, 35 for CO2/CO, 13 for CO2/CH4 at lower temperatures revealed that the material has much better selectivity values than many HCP (hyper-crosslinked polymer) derivatives in the literature even from its most similar analog dimethoxymethane derivative TATHCP, which has a surface area of 950 m2/g.

Utilization of recycled polyester nonwovens as sorbent for oil spill cleanups

Purpose The most widely recycled plastic in the world is recycled polyethylene terephthalate (rPET). To minimize the environmental related issues associated with synthetic fibers, several researchers have explored the potential use of recycled polyester fibers in developing various technical textile products. This study aims to develop needle-punched nonwoven fabrics from recycled polyester fibers and investigate its suitability in oil spill cleanup process. Design/methodology/approach According to Box and Behnken factorial design, 15 different needle-punched nonwoven fabrics from recycled polyester fibers were prepared by changing the parameters, namely, needle punch density, needle penetration depth and fabric areal weight. Several featured parameters such as oil sorption, oil retention, oil sorption kinetics, wettability and reusability performance were systematically elucidated. Findings The maximum oil sorption of recycled nonwoven polyester is found to be 24.85 g/g and 20.58 g/g for crude oil and vegetable oil, respectively. The oil retention is about 93%–96% in case of crude oil, whereas 87%–91% in case of vegetable oil. Recycled polyester nonwoven possesses good hydrophobic–oleophilic properties with static contact angle of 138° against water, whereas 0° against crude oil and vegetable oil. The reusability test results indicate that recycled polyester nonwoven fabric can be used several times because of its reusability features. Originality/value There is no detailed study on the oil sorption features of needle-punched nonwoven fabrics developed from recycled polyester fibers. This study is expected to help in developing fabrics for oil spill cleanups.

Enhancing methylene blue sorption on spotted golden thistle stalks by soft chemical pretreatments

Soft chemical treatments of dried stalks of the spotted golden thistle yielded novel sorbents; both the stiff nature and mass of the raw material were preserved. For minimal environment impact, the solution concentrations of the tested reagents were optimized at ambient temperature. The sorbents obtained were tested for the removal of methylene blue. The approach used kinetics and equilibrium studies. NaOH (0.1 mol L−1) treatment was efficient and afforded two new materials with seriously improved sorption features: the equilibrium time was reduced from 17–19 h to 10–12 h whilst, maximal sorption capacity increases from 65 to 100 and 112 mg g−1 i.e., enhancements of 54 and 72%. The Avrami model followed by the pseudo second-order model, best fitted the kinetic data. The isotherms were of Hmx type and were satisfactorily fitted to the Redlich-Peterson model. The Langmuir, Tóth, and Sips models were suitable to describe the H type isotherms relating to limited data ranges. Microanalysis, scanning electron microscopy (SEM), SEM coupled to energy dispersive X-ray, and attenuated total reflectance infrared spectroscopy showed an increase of the lignocellulosic content and the strengthening of the interactions between the dye and the sorbent. However, zeta potential measurements showed that the charge of the surface became almost inexistent after the pretreatment.

Экспериментальное моделирование взаимодействия материалов гидроботанических площадок с компонентами аэротехногенных выбросов

The article presents evaluation results of metal accumulation processes by filtering containers based on mining waste. Serpentine-reached grainy material (an enrichment product of phlogopite mining waste) was used for sorbing heavy metals from atmospheric precipitation. It has been established that the serpentine-reached grainy material is characterized by useful sorption features with respect to heavy metals and high content of calcium, magnesium and silicon.

Sorption Features of Polyurethane Foam Functionalized with Salicylate for Chlorpyrifos: Equilibrium, Kinetic Models and Thermodynamic Studies.

Commercial polyurethane foam was treated with salicylate salt to synthesize PUFSalicylate (PUFS) as a novel, promising, stable and inexpensive adsorbent for chlorpyrifos (CPF) extraction. The properties of PUFS were investigated using UV–Vis spectroscopy, apparent density, FTIR spectroscopy, pHZPC, BET surface area, elemental analysis, TGA and DTG tests. Batch experiments were performed for the sorption of CPF under different salicylate concentrations, pH, shaking time, ionic strength, agitation speed, sorbent mass, batch factor and initial concentration of CPF. The results confirmed that 97.4% of CPF in a 25 mL solution, 10 μg/L concentration, could be retained by only 0.3 mg of PUFS (1:105mass ratio of PUFS: solution). In addition, the maximum capacity of PUFS for the sorption of CPF was 1249.8 μg/mg (3.9 × 10−5 mol/g) within 180 min. The negative values of ΔH° and ΔG° indicated that the sorption of CPF onto PUFS is an exothermic spontaneous process (favorable). The calculated data from the experimental procedures fitted perfectly with Freundlich isotherm (R2 = 0.9952) and the kinetic Equation of pseudo-second order. In addition, the R2 value in the Elovich Equation recorded higher when compared to the Morris–Weber and Bangham Equations; hence, the pore diffusion is not the rate-determining step. Thus, the use of PUFSalicylate for the removal of chlorpyrifos contaminations from agriculture runoff is applicable.

Matrix-filler interactions and solvent sorption features of nanohydroxyapatite (nHA) embedded ethylene-co-vinyl acetate (EVA)-millable polyurethane (MPU) blends.

We report the solvent sorption features and matrix filler interactions of nanohydroxyapatite (nHA) embedded ethylene-co-vinyl acetate (EVA)-millable polyurethane (MPU) blends, using toluene, xylene, and t-butylacetate as probe molecules. The EVA/MPU blends were initially loaded with different quantities of n-HA, and the interfacial interactions were evaluated through FTIR and XRD techniques. The modulation of solvent resistance was subsequently examined in terms of filler loading, temperature and molar volume of the probes. With an increase in the amount of nHA, the solvent resistance of the matrix has been found to be enhanced, with the mechanism of transport regularly deviating from the conventional Fickian mode normally followed by elastomer matrices. The Flory-Rehner equation was employed to compute the molecular mass between crosslinks (Mc) and the crosslink density (γ). The observed enhancement in the crosslink density and the degree of reinforcement has been attributed to the increased polar-polar interactions after nHA loading into the matrix. The experimentally obtained values of Mc have been compared with phantom and affine models, to identify the type of deformation happening under solvent stress. The reinforcement effect within the matrix, as a function of filler loading, has been verified by using the Kraus equation. The swelling resistance of the composites has also been verified in biological fluids in view of the possible biofield applications of the composites.

Utilization of Modified Attapulgite for the Removal of Sr(II), Co(II), and Ni(II) Ions from Multicomponent System, Part I: Kinetic Studies.

Radionuclide sorption by natural and modified clays is extensively accepted to be an important process from the radioactive waste point of view. This work focused on modification of natural attapulgite with a layered double hydroxide to produce a novel chemisorbent for Sr2+, Ni2+, and Co2+ removal from multicomponent solution. The structural and surface characteristics of both attapulgite (ATP) and modified attapulgite (LDH-ATP) were investigated using XRD, FTIR, SEM, and thermal analysis. Comparison of sorption features of Sr2+, Ni2+, and Co2+ onto ATP and LDH-ATP was achieved; the results indicated that LDH-ATP was the most efficient sorbent for Sr2+, Ni2+, and Co2+. Kinetic studies established that the sorption is fast and reaching >90% within 30 min. The sorption of Sr2+, Ni2+, and Co2+ are well defined by non-linear pseudo-second-order model and controlled by an intra-particle diffusion mechanism. The diffusivity was determined using homogeneous surface diffusion (HSDM) model and found in the order 10-13 m2/min; this confirmed that the sorption of the three ions is chemisorption process. LDH-ATP can be employed as a candidate chemisorbent for the removal of some metal ions from waste solution.

Cation‐bioimprinted mesoporous polysaccharide/sol–gel composites prepared in media containing choline chloride‐based deep eutectic solvents

ABSTRACTA study on the Pb(II) imprinting performed within mesoporous sulphated biopolymer/siloxane composites, prepared in media containing deep eutectic solvent (DES), is described. In general, the process of imprinting resulted in greatly increased surface areas relatively to the corresponding nonimprinted composites [up to fivefold (from 76 m2 g−1 to 360 m2 g−1) for fucoidan (Fuc) and up to twofold (from 208 m2 g−1 to 351 m2 g−1) for chondroitin sulfate (CS) composites], the diminishing of mean pore size (from 3.3–4.6 nm to 2.9–3.4), and higher biopolymer contents (from mass fractions of 0.42–0.52 to 0.46–0.68). The sorption features depended a great deal on the biopolymer/DES combination. The best CS composite, allowed for 12% capacity and 20% binding strength, as well as Pb(II)/Cd(II) selectivity enhancements. The largest of the capacities was obtained with the imprinted Fuc/DES‐E composite, 86 mg g−1, a 10% increase. Concerning the selectivity [Pb(II) versus Cd(II)], there was a significant increase for the CS composites (from 1.0–1.1 (αqmax)/1.1–1.2 (αK) to 1.3–1.4 (αqmax)/1.3–1.6 (αK)]. In particular, the DES‐E CIC presented high selectivity factors (αqmax 3.0/αK 3.2) in line with those of the microporous version (αqmax 2.0/αK 3.3) but showing a significant increase in terms of the αqmax selectivity. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48842.

Sorption characteristics of uranium from sulfate leach liquor by commercial strong base anion exchange resins

The extraction of uranium from natural rock is extremely vital in field of nuclear applications. In this work, the sorption properties of uranium from sulfate leach liquor using Amberlyst A-27 and Dowex 21K resins were evaluated. The sorption features such as contact time, initial pH value, initial uranium concentration and temperature, were optimized to get the best sorption uptake. The models calculations of sorption including kinetics, isotherm and thermodynamic were applied. The highest sorption capacity of uranium on Amberlyst A-27 and Dowex 21K was 131.57 and 105.26 mg/g respectively. The sorption process was confirmed using (XRF), FTIR and SEM techniques. The XRF data emphasized that uranium was sorbed on the resins as uranyl sulfate.

The triple-sorbents solid-phase extraction for pharmaceuticals and estrogens determination in wastewater samples

In the presented study, the applicability of four sorbent materials (active carbon, neutral alumina, Primary and Secondary Amines (PSA), and Florosil) applied on top of a polymeric Strata-X column was tested to improve the solid-phase extraction of 15 analytes (pharmaceuticals and estrogens) from water. Deionized water and water fortified by humic acids (representatives of dissolved organic matter) were the tested matrices. The effect of water acidification was tested as well. The values of recovery show that sorbents often have different sorption features towards pharmaceuticals with acidic and basic functional groups. PSA shows sorption towards humic acids, thereby can minimize the matrix effect obtained during final quantification by chromatographic techniques coupled with mass spectrometry. The slight sorption of basic pharmaceuticals to humic acids was found out. Finally, a mixture of PSA and alumina was used, and the validated SPE-GC/MS(SIM) method was applied for raw and treated wastewater. A triple-sorbent solid-phase extraction cause lower matrix effect compared to the previous study. This small innovation in the SPE procedure (without any significant cost enhancement and extension of the duration) can have an impact on the quantification of the pharmaceuticals and estrogens, and improve the reliability of the results.

Coal Anisotropic Sorption and Permeability: An Experimental Study

Knowledge of the bedding plane properties of coal seams is essential for the coalbed gas production because of their great influence on the inner flow characteristics and sorption features of gas and water. In this study, an experimental study on the anisotropic gas adsorption–desorption and permeability of coal is presented. The results show that during the adsorption–desorption process, an increase in the bedding plane angle of the specimen expands the length and area of the contact surface, thereby increasing the speed and quantity of adsorption and desorption. With an increase in the bedding angle, the number of pores and cracks was found to increase together with the volumetric strain. The evolution of permeability of coal heavily depended on stress–strain stages. The permeability decreased with the increase of stress at the initial compaction and elastic deformation stages, while it increased with the increase of stress at the stages of strain-hardening, softening and residual strength. Initial permeability increased with increasing bedding angle.

Modifikacija poliestarske pletenine za ekonomičnije bojenje

This article discusses the process of modification of the polyester knitted fabric as a prerequisite for successful dyeing at a lower temperature and without the presence of the carrier. The processing preceding dyeing, alkali-alcohol hydrolysis with ultrasound, changes the surface morphology causing the peeling and cracks on the surface of polyester fibres of the knitted fabric, decreases the mass and thickness of the knitted fabric, improves the sorption features, capillarity and absorption of water and soaking. The process of dyeing of the modified polyester knitted fabric in the presence of ultrasound at the lower temperature gives much better results than dyeing without ultrasound, and it is very close to the standard process of dyeing of a raw sample at the higher temperature. By increasing the concentration, the level of dye exhaustion per mass unit of the knitted fabric decreases. At the highest applied dye concentrations and the longest dyeing, the biggest dye adsorption happens.

A toxicokinetic model for fish including multiphase sorption features.

In the scientific field of physiologically based toxicokinetic modeling the complexity of the model used depends on the complexity of the problem to be handled, leading to a broad range of existing models from simple 1-box models to complex multicompartment models. Most of these models work with lumped parameters, for example, an uptake efficiency parameter that can only be obtained with a fit of experimental data. The authors' goal was a model that is completely based on well-defined physiological and physicochemical parameters. Lumped parameters fitted on training data sets would limit the model's applicability. This would enable a new view on process understanding for uptake, distribution, and elimination procedures. Eventual goals are a better localization of chemicals within the organism itself, and to set the stage for future extensions toward ionic compounds and active transport across membranes. The model evaluation reported in the present study has shown that uptake, clearance, and bioaccumulation data for nonpolar chemicals are well predicted. Environ Toxicol Chem 2017;36:1538-1546. © 2016 SETAC.

Metal cation sorption ability of immobilized and reticulated chondroitin sulfate or fucoidan through a sol-gel crosslinking scheme

An immobilization scheme, via glycidyloxypropyl-trimethoxysilane sol-gel crosslinking, of chondroitin sulfate (CS) or fucoidan (Fd), inspired by the biological silicate bridge found in CS, is presented here. It revealed to constitute a simple and effective way of producing biopolymer-silicate composites without compromising the carboxylate- and sulfate- groups of the biopolymers, those which play a determinant role in the binding to metal cations. In the case of the Fd composite, the immobilization process resulted in the ∼4-fold enhancement of the negatively charged sorption sites, probably due to unfolding effects induced by the synthesis conditions. Textural analysis of the composites showed a microporous, low surface area (6–12m2/g), microstructure which did not prevent the observation of relevant sorption features for metal cations, especially for Pb(II) and Cd(II). Rate constants (1–14g/mgmin−1) and affinity constants (79–370L/mg) in the same order of magnitude of chitosan-based sorbents were determined, whereas capacities (2–24mg/g) were smaller than the generality of those same sorbents. Globally, the sorption of metal cations by the Fd composite was superior to that by the CS composite. Furthermore, high stability of the sorbents and acceptable reproducibility of the synthesis was observed. Overall, the developed scheme of immobilization of CS and Fd appears capable of providing an effective way for integrating these biopolymers into metal cation-related applications such as biosorption, sensing or separation.

Frontispiece: A Bifunctional Metal–Organic Framework: Striking CO2‐Selective Sorption Features along with Guest‐Induced Tuning of Luminescence

Frontispiece: A Bifunctional Metal–Organic Framework: Striking CO₂‐Selective Sorption Features along with Guest‐Induced Tuning of Luminescence

A Bifunctional Metal-Organic Framework: Striking CO2 -Selective Sorption Features along with Guest-Induced Tuning of Luminescence.

A phenanthroline-functionalized CdII aminoterephthalate [Cd(NH2 -bdc)(phen)]n (NH2 -bdc=2-aminobenzenedicarboxylic acid, phen=1,10-phenanthroline) metal-organic framework (MOF) displays CO2 -selective adsorption properties and photoluminescence induced by phenolic guests. The inherently guest-free, rigid amine-rich framework exhibits substantial CO2 -selective adsorption at ambient temperatures (both at 273 and 298 K) over other flue gases like N2 , CH4 , O2 , Ar and H2 , with a high isosteric heat of adsorption at zero coverage (ΔHads ≈34 KJmol-1 ). Moreover, the fluorescent phenanthroline guest introduced to the MOF results in an excellent photoluminescence signature, which can serve as a marker for tuning phenolic-guest-induced luminescence. This marks the first report of observing distinct fluorescence responses to differentially functionalized phenolic analytes, in the domain of coordination polymer materials.

Interface and strain effects on the H-sorption thermodynamics of size-selected Mg nanodots

This work deals with the thermodynamics of hydride formation in 3-D nanoconfined Mg. Two ensembles of nearly monodisperse Mg nanodots (NDs) with different diameters (60 and 320 nm), were grown by the template nanopatterning method, using ultra-thin alumina membranes (UTAMs) with ordered porosity as evaporation masks. Multilayer NDs consisting of 30 nm Mg, 5 nm Ti and 5 nm Pd were deposited on UTAM-coated glass substrates by molecular beam epitaxy. The lateral surface of the NDs is constituted by native MgO. The morphology of the NDs was characterized by field emission scanning electron microscopy and atomic force microscopy. Hydride formation and decomposition was studied at low temperature (363–393 K) by means of optical hydrogenography. Compared to bulk Mg, the plateau pressure for hydrogen absorption in NDs exhibits an upward shift, which is larger for small NDs. Differently, the desorption plateau pressure is almost the same for the two NDs size and is lower than for bulk Mg. These hydrogen sorption features are discussed in the frame of a model that takes into account both interface energy and elastic strain energy in the constrained nanodots. The onset of plastic deformation, marked by a high pressure hysteresis between hydrogen absorption and desorption isotherms, limits the extent of hydride destabilization that can be achieved by elastic strain engineering.