Adsorbent For Purification Research Articles

Simultaneous determination of seven nitrogen-containing phenyl ethers in cosmetics by gas chromatography with mass spectrometry and dispersive solid-phase extraction.

An analytical method was established for the simultaneous determination of seven nitrogen-containing phenyl ethers (2-anisidine, 3-anisidine, 4-anisidine, 2-nitroanisole, 3-nitroanisole, 4-nitroanisole, and 3,3'-dimethoxybenzidine) in cosmetics by gas chromatography with mass spectrometry in this work. The samples were extracted with ethyl acetate and purified with primary secondary amine during the dispersed solid-phase extraction. The analytes were separated by a DB-17MS column and detected in the electron ionization mode of mass spectrometry in the selected ions monitoring mode. The extraction solvent, purification adsorbents, and chromatographic column behavior were optimized. The results indicated that the seven analytes show good linear relationship (R2 > 0.9965) in the concentrations of 5.0-5000μg/L. The quantitation limits of the method ranged from 19.0 to 84.8μg/kg. The recovery rates of seven analytes were in the range of 72.6-114% with the relative standard deviations of 1.1-7.5%. Real sample analyses showed that this accurate and precise method could be appropriate for simultaneous determination of seven nitrogen-containing phenyl ethers in cosmetics.

Significance of porosity and pore accessibility for the selection of ion exchange adsorbents for chromatographic purification of macromolecules

Selection of adsorbent for the development of purification process for biomolecules is crucial due to the requirement of large number of binding sites and adsorption area. Considering this, porous structure with high charge density is selected as an adsorbent for macromolecule purification. Such selection may provide high static binding capacity but causes loss of separation performance due to improper porosity of adsorbent in comparison to solute sizes involved. To address this problem for the screening of adsorbent, this work reports adsorbent selection procedure on the basis of adsorbent pore diameter (dp), solute hydrodynamic dimensions (RH), and flow velocity in support of binding capacity. Towards that end, this study evaluated the pore accessibility performance of varying characteristics adsorbents using tracers like acetone, lysozyme, and bovine serum albumin (BSA) by designing nonbinding conditions. All screened adsorbents showed certain loss of total surface area depending on the solute dimensions and pore size. Sepharose type adsorbents showed accessible area loss up to 25% for lysozyme and 50% for BSA. Sepabeads type showed 30% loss, while macroporous UNO type showed only 7% loss of surface area for lysozyme. The study correlates accessibility with size ratio β (dp/RH). The value of β > 38 is found to be required for the accessibility of total pore area and optimum separation performance of ion exchangers investigated. Accessibility and β provide useful information for the selection of suitable adsorbent for the purification of macromolecules.

HPLC determination of domoic acid in shellfish based on magnetic molecularly imprinting polymers

ABSTRACTA magnetic molecularly imprinting polymer for domoic acid was fabricated. Synthesis conditions were optimized. The polymer particles have high magnetization for rapid magnetic separation. The apparent maximum absorption amount and dissociation constant of the polymer were 1,600 µg g−1 and 20.6 µg mL−1, respectively. The polymer retained 90% of adsorption amount after 5 times of repeated use. It was used as an adsorbent for purification and HPLC detection of domoic acid in shellfish with a detection limit of 0.050 µg g−1. Thus, the polymer could be applied to the sample pretreatment of aquatic products.

Magnetic Mineral Nanocomposite Sorbents for Wastewater Treatment

Magnetic nanocomposite sorbents for disposal of synthetic detergents from wastewater were synthesized. Obtained sorbents based on clay minerals (saponite, palygorskite, and spondyle clay) and magnetite were characterized by X-ray powder diffraction, Mössbauer spectroscopy, and ballistic method with Steinberg magnetometer. As a result, the average crystallite sizes of Fe3O4 nanoparticles in magnetic nanocomposites were 2–10 nm. Magnetic nanocomposites had superparamagnetic properties and were classified as soft magnetic materials. Comparison of sorption properties showed that magnetic composite sorbents had efficiency of adsorption removal of anionic surfactants and polyphosphates from aqueous solution 2–8 times higher compared to native clay minerals. Spent magnetic nanocomposites were effectively removed from the aqueous solution by magnetic separation. So, the efficiency of magnetic composites application and implementing of magnetic separation in adsorption purification was confirmed.

INCREASE OF QUALITY OF BIOMETHANE USED FOR HYDROGEN SYNTHESIS

The paper studies the features of biomass energy use and presents the main directions of biogas application. It is shown the connection between the main indicators of biogas quality and the possibility of its use in various technological processes. The relevance of improving the quality of biomethane used for synthesis of high purity hydrogen is substantiated. The classification of the methods for separation and purification of methane-containing gas mixtures is given, their advantages and disadvantages are analyzed. Comparative characteristics of the presented methods for cleaning quality, specific energy costs, and design features are given. A method of short cycle free adsorption for bio-gas purification is proposed as the most economically feasible for small capacity plants. The main types of industrial adsorbents are considered. The dependence of sorption properties on the effective pore diameters of sorbent materials is shown. The distinctive features of adsorption in microporous structures are noted. The most significant of these features is the high value of the adsorption energy in comparison with adsorption materials having larger pores in the structure. Among microporous adsorbents, zeolites are identified as the most promising. The adsorption properties of synthetic and natural zeolites are analyzed. The theoretical bases of the adsorption purification processes are considered, the adsorption competition of the main macrocomponents of the gas mixture being cleaned is evaluated. The scheme of the experimental installation and the process of separation and purification of biogas using natural zeolite as an adsorbent are described. The results of application of a natural zeolite for the production of high purity biomethane due to purification from water vapor, hydrogen sulphide and adsorption of carbon dioxide are presented. The conversion of biomethane to hydrogen was noted as the most promising direction of biomass energy use, the advantages of using natural zeolites for obtaining high purity biomethane are shown.

Methyl mercaptan removal from natural gas using MIL-53(Al)

MIL-53(Al) was synthesized using hydrothermal method with various synthesis and calcination conditions. The synthesized materials were characterized by Powder X-ray Diffraction (PXRD), Thermal Gravimetric Analysis (TGA) and N2 adsorption-desorption isotherms (BET surface area measurement) methods. The results showed that synthesis time and calcination time can be decreased two days and one day, respectively, with respect to the usual method with no significantly decrement in the BET surface area and the crystallinity of materials. The sorption equilibrium, thermodynamic and kinetic of methyl mercaptan (MeSH) and methane adsorption on the MIL-53(Al) were studied by the volumetric method using a home-made apparatus. The sorption isotherm of MeSH revealed type IV according to IUPAC classification, while a type I was observed in the profile of the methane sorption isotherm. The synthesized MIL-53(Al) displayed high methyl mercaptan adsorption capacity (more than 9 mmol/g) which is about 2–3 times more than 13X, the usual industrial adsorbent for mercaptan removal from natural gas. The various models such as Langmuir, Sips and Thoth were successfully used to fit the adsorption experimental data. The Extended Langmuir (EL) and Ideal Adsorbed Solution Theory (IAST) models along with the pure component isotherm fitted to the Langmuir model were used to predict the removal of MeSH from methane-rich mixture. MIL-53(Al) presented high selectivity (EL selectivity of 263) for MeSH over methane. The isosteric heat of MeSH and CH4 adsorption on the MIL-53(Al) were within the range of 26–50 and about 18 kJ mol−1 respectively. Multiple adsorption–desorption cycles showed that the MeSH adsorption on the MIL-53 was highly reversible with a desorption efficiency of up to 95%. The diffusion time constants of MeSH and CH4 in the MIL-53(Al) at 298 K were estimated to be 1.48 × 10−2 and 1.99 × 10−2 s−1, respectively, leading to relatively equal adsorption kinetics of both molecules. High adsorption capacity, good kinetics, easy regeneration and reversible process of MeSH adsorption, suggested that the MIL-53(Al) can be used as a favorable adsorbent for purification of natural gas or biogas in the Pressure Swing Adsorption (PSA) process.

Selective nitrogen capture by porous hybrid materials containing accessible transition metal ion sites.

Selective dinitrogen binding to transition metal ions mainly covers two strategic domains: biological nitrogen fixation catalysed by metalloenzyme nitrogenases, and adsorptive purification of natural gas and air. Many transition metal-dinitrogen complexes have been envisaged for biomimetic nitrogen fixation to produce ammonia. Inspired by this concept, here we report mesoporous metal-organic framework materials containing accessible Cr(III) sites, able to thermodynamically capture N2 over CH4 and O2. This fundamental study integrating advanced experimental and computational tools confirmed that the separation mechanism for both N2/CH4 and N2/O2 gas mixtures is driven by the presence of these unsaturated Cr(III) sites that allows a much stronger binding of N2 over the two other gases. Besides the potential breakthrough in adsorption-based technologies, this proof of concept could open new horizons to address several challenges in chemistry, including the design of heterogeneous biomimetic catalysts through nitrogen fixation.

Engineering design and experimental study of indoor air adsorption purification for people’s health by removing hazard gases of H2S and NH3 using different carbon adsorbents with filter and matrix

The hazard gases of H2S and NH3 should be removed from farms, abattoirs and public toilets, etc. Adsorption purification technology is one efficient way to remove the hazard gases. By the scanning electron microscope of the different filters of activated carbon fiber type filter, paper honeycomb type filter and activated carbon sponge type filter, we find that the surface of activated carbon sponge type filter is roughest, that is beneficial for adsorption performance. The experimental results show that activated carbon sponge type filter has the highest adsorption removal efficiency of H2S and NH3. In addition, H3PO4 can improve the removing efficiency of NH3 in activated carbon sponge type filter. At last, the total removing efficiency of H2S and NH3 can attain 100 and 96%, respectively. Adsorption purification technology with high efficient adsorbents is one efficient way to remove the hazard gases for human health.

Synthesis of NiCo2O4 nanostructures with different morphologies for the removal of methyl orange

Aiming to investigate the adsorption removal performance of NiCo2O4 as water purification adsorbents, magnetic materials NiCo2O4 with six different morphologies were successfully synthesized by a facile method. NiCo2O4 with six different morphologies were characterized by scanning electron microscope, Fourier transform infrared spectroscopy, X-ray diffraction, N2 adsorption-desorption, vibrating sample magnetometry and X-ray energy dispersive spectrometry. In this study, we mainly explored the effect of specific surface area, pore volume and pore size on the performance for the removal of methyl orange, and the adsorption capacity followed an order of (b) NiCo2O4 nanorods>(e) balsam-like NiCo2O4>(f) rose-like NiCo2O4>(d) NiCo2O4 nanoribbons>(a) NiCo2O4 flowerlike nanostructures>(c) dandelion-like NiCo2O4 spheres. The results indicated that NiCo2O4 nanorods exhibited better adsorption performance. The reasons for the excellent adsorption capacity of NiCo2O4 nanorods were also discussed in depth by analyzing scale and surface characteristics. Besides, NiCo2O4 could be easily recovered from solution, which may avoid potential secondary pollution. Moreover, adsorption kinetics, the influence of pH and adsorption mechanism were comprehensively investigated. This finding indicated that NiCo2O4 were promising adsorbents for water purification.

Regeneration of activated carbon used in adsorption purification of alkanolamines

Regeneration of activated carbon used in adsorption purification of alkanolamines

Production of activated coal from the pits of apricots and peach for the adsorption purification of the waste Diethanolamine

Production of activated coal from the pits of apricots and peach for the adsorption purification of the waste Diethanolamine

Prospects for Hydrogen Production in Oil Shale Processing Industry in Estonia: Initial Aspects of Life Cycle Analysis

Climate initiatives as well as unpredictable changes of oil prices, requires fossil fuel industries urgently consider transition towards production of decarbonized fuels. Oil shale processing industry in Estonia also has been substantially effected by oil price drop. To improve the economic feasibility of the oil shale processing plant in Estonia, integration of a hydrogen production unit based on catalytic steam reforming technology with pressure swing adsorption purification is analysed in this paper. Methodology for evaluation of conventional oil shale processing industry transition to hydrogen production industry considering initial life cycle assessment elements is discussed in the paper.

Prokaryotic expression and purification of Chlamydomonas reinhardtii intraflagellar transport protein 46(IFT46) and preparation of polyclonal antibody

IFT46 is one of the important components of intraflagellar transport complex B in Chlamydomonas reinhardtii, and plays important roles in the assembly, movement and perception of ciliary. To study its functional mechanism, a GST-tagged and an MBP-tagged prokaryotic expression plasmid, pGEX-2T-ift46 and pMAL-C2X-ift46 were constructed, respectively, by inserting ift46 into the pGEX-2T and pMAL-C2X vector, and then transformed into Escherichia coli BL21 (DE3) for protein expression. SDS-PAGE (15%) analysis results showed that the molecular weights of the fusion protein GST-IFT46 and MBP-IFT46 were 70 kDa and 86 kDa, respectively. We used the fusion protein GST-IFT46 purified by affinity adsorption purification (more than 95% purity) for immunity to New Zealand white rabbits. The 5th immune serum was collected and the antibody titer was determined to be 256 000 by ELISA. The antiserum was purified by Protein A affinity adsorption purification and immobilized MBP-IFT46 purification, and the specificity of polyclonal antibodies was evaluated by Western blotting and immunofluorescence. Results showed that the polyclonal antibody prepared could specifically and precisely bind IFT46 in C. reinhardtii, and IFT46 was mainly concentrated at basal body regions and few localized along the entire length of the flagellum as punctuated dots, which will make a foundation to further study the mechanism of IFT46 in cilia related diseases such as obesity, diabetes and polycystic kidney disease.

Controlling the Integration of Polyvinylpyrrolidone onto Substrate by Quartz Crystal Microbalance with Dissipation To Achieve Excellent Protein Resistance and Detoxification.

Blood purification systems, in which the adsorbent removes exogenous and endogenous toxins from the blood, are widely used in clinical practice. To improve the protein resistance of and detoxification by the adsorbent, researchers can modify the adsorbent with functional molecules, such as polyvinylpyrrolidone (PVP). However, achieving precise control of the functional molecular density, which is crucial to the activity of the adsorbent, remains a significant challenge. In the present study, we prepared a model system for blood purification adsorbents in which we controlled the integration density of PVP molecules of different molecular weights on an Au substrate by quartz crystal microbalance with dissipation (QCM-D). We characterized the samples with atomic force microscopy, X-ray photoelectron spectroscopy, and QCM-D and found that the molecular density and the chain length of the PVP molecules played important roles in determining the properties of the sample. At the optimal condition, the modified sample demonstrated strong resistance to plasma proteins, decreasing the adsorption of human serum albumin (HSA) and fibrinogen (Fg) by 92.5% and 79.2%, respectively. In addition, the modified sample exhibited excellent detoxification, and the adsorption of bilirubin increased 2.6-fold. Interestingly, subsequent atomistic molecular dynamics simulations indicated that the favorable interactions between PVP and bilirubin were dominated by hydrophobic interactions. An in vitro platelet adhesion assay showed that the adhesion of platelets on the sample decreased and that the platelets were maintained in an inactivated state. The CCK-8 assay indicated that the modified sample exhibited negligible cytotoxicity to L929 cells. These results demonstrated that our method holds great potential for the modification of adsorbents in blood purification systems.

Adsorptive Purification of Aqueous Solution from Fluoride Ions by Carbonaceous Materials

Adsorptive Purification of Aqueous Solution from Fluoride Ions by Carbonaceous Materials

Gas adsorption properties of ZSM-5 zeolites heated to extreme temperatures

Zeolites are broadly useful catalysts and molecular sieve adsorbents for purification. In this work the thermal degradations of bare and platinum-loaded ZSM-5 was studied with the goal of understanding the behavior of nanoporous solids at extreme temperatures comparable to those present in nuclear fuels. Zeolites were heated in air and nitrogen at temperatures up to 1500°C, and then characterized for thermal stability via X-ray diffraction (XRD) and for gas adsorption by the Brunauer-Emmett-Teller (BET) method. Scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA) were also employed. These results indicate zeolites are stable when heat-treated up to 800°C and degrade slowly at higher temperatures. However, significant surface area degradation begins at 1025–1150°C with an activation energy of 400kJ/mole. At 1500°C, gas adsorption measurements and SEM images show complete collapse of the porous structure. Critically for nuclear fuel applications, however, the zeolites still adsorb helium in significant quantities.

Synthesis and lead absorption properties of sintered activated carbon supported zero-valent iron nanoparticle

In this study, the zero-valent iron nanoparticles (Fe0NPs) were immobilized on the sintered activated carbon (SAC). The prepared Fe0NPs-SAC was characterized with using scanning electron microscope (SEM), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) analyzer and atomic absorption spectrophotometry (AAS). The SEM morphology illustrated that Fe0NPs were well embedded in the SAC. The XRD peaks revealed that the addition of Fe0NPs did not change the crystal degree. The BET data showed that its surface area was 436.96 m2/g, average pore diameter was 2.377 nm and total pore volume was 0.060 cm3/g, while the corresponding values of SAC were 513.29 m2/g, 2.225 nm and 0.065 cm3/g. The AAS results indicated the iron loading amount was related with Fe0NPs/SAC ratio and reaction time in the preparing process. Subsequently, Fe0NPs-SAC was used as adsorbent to treat simulated lead bearing wastewater. The effects of pH, adsorbent dosage and iron loading amount were investigated. Moreover, water erosion resistance of the Fe0NPs-SAC was determined through released iron content in the static and shaking water. The results showed the prepared Fe0NPs-SAC was not only effective but also safe adsorbent for purification of drinking water.

Affitins for protein purification by affinity magnetic fishing

Currently most economical and technological bottlenecks in protein production are placed in the downstream processes. With the aim of increasing the efficiency and reducing the associated costs, various affinity ligands have been developed. Affitins are small, yet robust and easy to produce, proteins derived from the archaeal extremophilic ⿿7kDa DNA-binding⿿ protein family. By means of combinatorial protein engineering and ribosome display selection techniques, Affitins have shown to bind a diversity of targets. In this work, two previously developed Affitins (anti-lysozyme and anti-IgG) were immobilized onto magnetic particles to assess their potential for protein purification by magnetic fishing. The optimal lysozyme and human IgG binding conditions yielded 58mg lysozyme/g support and 165mgIgG/g support, respectively. The recovery of proteins was possible in high yield (⿥95%) and with high purity, namely⿿⿥95% and 81%, when recovering lysozyme from Escherichia coli supernatant and IgG from human plasma, respectively. Static binding studies indicated affinity constants of 5.0ÿ104M⿿1 and 9.3ÿ105M⿿1 for the anti-lysozyme and anti-IgG magnetic supports. This work demonstrated that Affitins, which can be virtually evolved for any protein of interest, can be coupled onto magnetic particles creating novel affinity adsorbents for purification by magnetic fishing.

The influence of purifier models on hydrogen network optimization: Insights from a case study

Many researchers have integrated hydrogen networks with membrane separation and pressure swing adsorption (PSA) purification devices in order to minimize hydrogen utility consumption in refineries. However, few have realized the influence parameters of purifiers have on the hydrogen network. Several simplified purifier models can be observed in literature, but the accuracy and applicability of these simplified models have not been reported yet. In this paper, the impact of a purifier on the hydrogen network was revealed from three aspects by a numerical method. The three aspects included the material selectivity, the pressure ratio and the network parameters. Insights from the case study shows that the network parameter has less of an influence on the network performance compared to the purifier parameters.

Исследование процесса адсорбционной очистки природных газов на цеолите СаХ

Исследование процесса адсорбционной очистки природных газов на цеолите СаХ