Large Adsorption Capacity Research Articles

Chitosan-based dual network composite hydrogel for efficient adsorption of methylene blue dye

With the rapid development of the textile industry, a large amount of dyeing wastewater discharge has caused great harm to the ecological environment. In this work, a dual-network, composite hydrogel adsorbent with excellent mechanical properties, good reusability, and large adsorption capacity was prepared by introducing chitosan cross-linked polyvinylamine into the N,N′-methylenebisacrylamide cross-linked polyacrylic acid network. The dual cross-linking network gave the hydrogel excellent mechanical properties with maximum tensile stress and strain up to 1.9 MPa and 920 %. The adsorption capacity of methylene blue on hydrogel was up to 596.14 mg/g. In addition, the prepared hydrogel exhibited good reusability, and their adsorption efficiency remained above 85 % in five consecutive cycles. The adsorption behavior was well fitted by Pseudo-second-order kinetics and the Langmuir equation, indicating that the hydrogel was chemisorbed to the dye as a monolayer. The adsorption mechanism analysis showed that the electrostatic interactions and hydrogen bonding between the functional groups of the hydrogels and methylene blue molecules contributed to the good adsorption capacity. Overall, the synthesized composite hydrogels could be used as an efficient adsorbent for the removal of methylene blue dye, particularly from textile industry wastewater.

Magnetic porous carbons derived from metal-organic frameworks for effective adsorption of tetracycline

Recovery of adsorbent from solid-liquid adsorption system is important for the application of adsorption technique. Due to high efficiency and low cost, separation induced by external magnetic field has attracted large attentions. In this work, we prepared a series of cobalt-doped magnetic porous carbons (Co-PC) via using Co-benzimidazole (Co-PhIm) as the precursor. In the green synthesis of Co-PhIm, water was used to partly substitute the organic solvent that was applied in previous reports. Interestingly, upon the addition of water, the porosity was boosted and the magnetism was not weakened obviously. Among the prepared porous carbons, the optimized Co-PC-C exhibited a large adsorption capacity (998.3 ​mg ​g−1) for tetracycline (TC) and rapid equilibrium time (30 ​min) at low concentrations. Co-existing ions had almost ignorable interferences and the optimized pH was found near the neutral environment. Furthermore, this material can be well regenerated through a simple elution method. Therefore, our work provides an effective adsorbent for TC antibiotic and proposes a guideline to enhance the porosity of adsorbent.

Resource mining from stainless steel pickling wastewater to produce metal-organic frameworks

Metal-organic frameworks (MOFs) exhibit large potential in many fields while the high cost limits their large-scale use. Herein, stainless steel pickling wastewater was successfully transformed to Fe/Cr-MIL-100, during which Ni2+ was largely purified. As an integration of metal, solvent and acid modifier, the use of the wastewater simplifies the preparation units and reduces the cost of MOFs. Conversion of the pickling wastewater to MOFs is feasible under wide reaction conditions and is not interfered by discharge batch of the wastewater. The obtained MIL-100 s products exhibit excellent porosity, long-term acid/base stability, and large adsorption capacities for methylene blue, moxifloxacin hydrochloride, and zirconium (IV) ion. Thus, our work provides a new insight for effective reuse of industrial wastewater and a feasible method for reducing MOFs cost.

Synthesis of zirconium-coated lithium ion sieve with enhanced cycle stability

Lithium manganese oxide ion sieves (LMO-type) have excellent application prospects for extraction of lithium from brine due to their high adsorption capacities and superior selectivities. However, the dissolution loss of Mn affects their structural stability, and limits their industrial application. In this study, the zirconium-coated lithium ion sieve precursor LMZO was prepared by coating zirconium oxide into Li1.6Mn1.6O4 and performing solid-phase combustion. The results revealed that after acid leaching, the spinel structure and porous morphology of LMZO were maintained, which is beneficial for subsequent Li+ adsorption. The dissolution loss rate of Mn2+ decreased from 0.89 % to 0.349 % after coating, which was superior to that of pristine or coated Li1.6Mn1.6O4 materials previously reported. The lithium adsorption capacity of the zirconium-coated lithium ion sieve HMZO from Qinghai Kunty salt lake brine containing multiple coexisting ions was maintained at 25.96 mg/g at a Mg2+/Li+ concentration ratio of as high as 70, indicating that HMZO could be directly applied to highly saline brines. After 15 adsorption and desorption cycles, HMZO maintained a low dissolution loss of Mn and a large lithium adsorption capacity. This conclusion showed that HMZO has stable structure and excellent industrial application value. The Mn valence was higher in HMZO because the coating slowed the dissolution of Mn3+ and prevented dissolved Mn2+ from entering the solution; thus, the dissolution loss of Mn from HMZO was low. The adsorption of Li+ conformed to the pseudo-second-order kinetics model, indicating a Li+-H+ ion exchange mechanism.

Novel molecularly imprinted phenolic resin–dispersive filter extraction for rapid determination of perfluorooctanoic acid and perfluorooctane sulfonate in milk

Perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS) are emerging pollutants that threaten food safety. Herein, a rapid, accurate, and selective method for determination of PFOA and PFOS in milk was established by using new molecularly imprinted phenolic resin (MIP-PR) as the adsorbent of dispersive filter extraction (DFE) combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS). MIP-PR was synthesized at room-temperature using m-aminophenol, glutaraldehyde, and perfluorononanoic acid as the monomers, cross-linkers, and virtual templates, respectively, and exhibited rapid mass transfer (30 s), high selectivity (imprinted factors > 3.7), and large adsorption capacity (>54.6 mg/g). Compared with reported methods, the developed MIP-PR–DFE method is fast, selective, inexpensive, and shows good purification and enrichment efficiency. The proposed MIP-PR–DFE–LC-MS/MS exhibited low limits of detection (0.006–0.022 ng/mL), high recoveries (94.7–109 %), and good precision (RSDs ≤ 9.5 %). This study provides a new idea for the development of imprinted resin adsorbents for perfluorinated compound, and a new method for sample pretreatment for monitoring of PFOA and PFOS in food.

Preparation of Quercus mongolica leaf-derived porous carbon with a large specific surface area for highly effective removal of dye and antibiotic from water

Quercus mongolica leaf (QL), an easily available biomass, was used as the precursor for preparing the hierarchical porous carbon with a large specific surface area and high adsorption capacities toward the representative dye and antibiotic. After being carbonized, QL was further chemically activated, and potassium hydroxide was proved to be a better activator than sodium hydroxide. The QL-derived porous carbon (PCQL) exhibited abundant micro- and mesopores, and the specific surface area reached 3275 m 2 g −1 . The performances of PCQL were evaluated through adsorbing rhodamine B (RhB) and tetracycline hydrochloride (TC) from water. Four adsorption isotherm models (the Langmuir, Freundlich, Sips, and Redlich-Peterson models), three adsorption kinetic models (the pseudo-first-order, pseudo-second-order, and intra-particle diffusion models), and the thermodynamic equations were used to investigate the adsorption processes. The pseudo-second-order kinetic model and the Sips isotherm model fitted the experimental data well, which indicates that the adsorption processes were controlled by the amount of adsorption active sites on the surface of PCQL, and these adsorption active sites had different affinities for the adsorbates. The maximum adsorption capacities of PCQL toward RhB and TC were 1946.0 and 1479.6 mg g −1 , respectively, based on the Sips model. The thermodynamic analysis indicates that the adsorption of PCQL toward adsorbents was spontaneous physical processes accompanied by the increasing disorder degree. The adsorption mechanism was attributed to the combination of the pore-filling, hydrogen bond, and π-π interactions. Moreover, in the fixed-bed experiments, the Yoon-Nelson model fitted the breakthrough curves well, and about 8 L wastewater containing RhB (200 mg L −1 ) may be effectively treated by 1.0 g of PCQL. Above results indicate that QL is a promising precursor for preparing functional porous carbon materials.

The Synthesis and Characterization of Iron Sand-Based CuFe2O4 as Heavy Metal Ion Adsorbent

This study aimed to synthesize iron sand-based Copper Ferrite (CuFe2O4) using the coprecipitation method. The iron sand was taken from South Cianjur and used as a Fe cation source to synthesize CuFe2O4 nanoparticles. Three composition variations of CuCl2.6H2O and iron sand (Fe3O4) were employed, i.e., 1:1, 1:2, and 2:1. Samples were characterized using X-Ray Diffraction (XRD), Scanning Electron Microscopy - Energy Dispersive X-Ray (SEM-EDX), and Atomic Adsorption Spectroscopy (AAS). The XRD analysis exhibits three synthesis-phase results: CuFe2O4, Fe2O3, and CuO. The produced CuFe2O4 has two crystal structures: t-CuFe2O4 in 1:2 variation and c-CuFe2O4 in variations 1:1 and 2:1. Adding Cu resulted in smaller crystal size and higher lattice parameters. SEM-EDX analysis of 1:2 sample variation showed a round-shaped particle of 102.57 nm. AAS analysis showed that the increased mole of Cu decreases the heavy metal, including Pb and Mn, adsorption capacity. The largest adsorption capacity was found in the 1:2 (60.698 mg/g).

Adsorption Characteristics of Ionic Surfactants on Anthracite Surface: A Combined Experimental and Modeling Study.

Ionic surfactants are widely used in coal dust control in mines, and their adsorption characteristics on the coal surface have a great influence on the coal dust control effect. In this investigation, anionic sodium dodecylbenzenesulfonate (SDBS) and cationic octadecyltrimethylammonium chloride (STAC) were selected to explore the adsorption characteristics of ionic surfactants on the surface of anthracite. The experimental results show that the adsorption rate and efficiency of STAC on the surface of anthracite are higher than that of SDBS; STAC can form a denser surfactant layer on the surface of anthracite, with a larger adsorption capacity and higher strength. Molecular dynamics simulations show that the adsorption between STAC and the surface of anthracite is tighter, and the distribution at the coal–water interface is more uniform; the surface of anthracite modified by STAC has a stronger binding ability to water molecules.

High-Efficient Anionic Dyes Removal from Water by Cationic Polymer Brush Functionalized Magnetic Mesoporous Silica Nanoparticles

High efficiency removal of methyl orange (MO) and bromothymol blue (BT) dyes from contaminated water has been reported using magnetic mesoporous nanoparticles modified with cationic polymer brush (poly(2-methacryloyloxy)ethyl] trimethylammonium chloride solution) (Fe3O4-MSNs-PMETAC). Atom transfer radical polymerization (ATRP) was utilized to grow the polymer chains on the magnetic mesoporous silica nanoparticles. The chemical surface modifications were confirmed using IR, TGA, SEM and TEM. The results show that the obtained Fe3O4-MSNs-PMETAC materials were nearly spherical in shape with approximately 30 nm magnetic core, and silica shell thicknesses ranged from 135 to 250 nm. The adsorption performance of the material was found to be unaffected by the pH (3-9) of the media, with a removal efficiency of 100% for both dyes. The adsorption of BT and MO on the surface of Fe3O4-MSNs-PMETAC was found to follow Freundlich and Langmuir models, respectively. Since the synthesized nanocomposite materials exhibit an enhanced properties such as large maximum adsorption capacity, rapid synthesis process, and easy separation from solution, it could be an effective sorbent for the removal of other pollutants such as potentially toxic anionic elements (e.g., arsenate and chromate ions) from water and wastewater.

ZIF-8/Chitosan hybrid nanoparticles with tunable morphologies as superior adsorbents towards both anionic and cationic dyes for a broad range of acidic and basic environments

A series of nanohybrids using ZIF-8 in the presence of chitosan (CS) at various compositions (0.5–15 wt%) were synthesized. Thorough characterization exhibited that the morphology of the nanoparticles in terms of surface charge, particle size, specific surface area, and pore volume is significantly dominated by the CS content in the hybrid nanoparticles. Amongst the nanoparticles synthesized, a hybrid nanoparticle containing 2 wt% CS, named CS-ZIF-2, represented the largest positive zeta potential and smallest particle size. Moreover, adsorption experiments indicated that CS-ZIF-2 had considerable adsorption capacity against anionic dye (Congo Red, CR) compared with the individual ZIF-8 and CS samples suggesting its synergistic adsorption behavior. The maximum adsorption capacity of CS-ZIF-2 towards anionic dye was determined to be 500 mg/g, which was ∼20% more than single ZIF-8 nanoparticle. Despite the positive charge of ZIF-8 and its CS-ZIF nanohybrids, they exhibited considerably large maximum adsorption capacity towards cationic dye, e.g., ∼350 mg/g for malachite green. Such behavior was correlated to distinctive adsorption mechanisms other than electrostatic forces, such as π-π interaction and hydrogen bonding between dye molecules and adsorbents. Simultaneous adsorption of both cationic and anionic dyes over CS-ZIF-2 using a solution containing a mixture of two dyes confirmed the high adsorption capacity of this sample. Adsorption experiments at various pH levels showed that CS-ZIF-2 nanohybrid could be an efficient adsorbent for both anionic and cationic dyes at both acidic and basic conditions. Recycling experiments revealed that CS-ZIF-2 retained its adsorption capacity towards both cationic and anionic dyes after five-time recycling.

Pseudo-mercaptoethyl pyridine functionalized polyhedral oligomeric silsesquioxane-graphene composite via thiol-ene click reaction for highly selective purification of antibody

In this work, we prepared a novel graphene-based composite by combination of mercapto-end capped polyhedral oligomeric silsesquioxane (POSS-SH) with graphene oxide (GO) through covalent bonding process. The composite was further conjugated with 4-vinyl pyridine (4-VP) through thiol-ene click reaction to fabricate pseudo-mercaptoethyl pyridine functionalized POSS-graphene composite (G-POSS-S-VP). The physicochemical properties were confirmed via FT-IR, TGA, XPS, and TEM characterizations and a high ligand density of ca. 87.3 μmol m−2 was obtained. G-POSS-S-VP composite displayed high selectivity toward antibody, i.e., immunoglobulin G (IgG) in this case based on the hydrophobic charge induced chromatography (HCIC) mechanism. A high adsorption efficiency of ca. 90% and large adsorption capacity of 500 mg g−1 were achieved for IgG at pH 7.4. At the same time, the non-specific adsorptions of co-existing proteins on graphene substrate were obviously hindered. The practical applicability of G-POSS-S-VP composite as adsorbent was verified by selective separation of IgG from human serum. SDS-PAGE assay and MALDI-TOF-MS analysis clearly demonstrated the successful isolation of IgG with high purity.

Molecularly imprinted polymers coated on the surface of metal–organic frameworks combined with liquid chromatography-tandem mass spectrometry for the detection of free N-acetylneuraminic acid in serum of pneumoconiosis patients

Free N-acetylneuraminic acid (Neu5Ac) in serum is used as a biomarker for early diagnosis of pneumoconiosis. In this study, a novel adsorbent, molecularly imprinted polymers (MIPs) coated on the surface of metal–organic frameworks (MOFs) were synthesized for the specific adsorption of free Neu5Ac in human serum. This novel adsorbent exhibited the advantages of large adsorption capacity, fast mass transfer rate, and high specificity to Neu5Ac. The theoretical maximum adsorption capacity was 52.31 mg g−1, and the adsorption equilibrium could be reached in 2 min. The free Neu5Ac in serum samples was determined by liquid chromatography–tandem mass spectrometry (LC–MS/MS). The linear range of the detection system was 50 – 10000 ng mL−1. The limit of detection (LOD), and the limit of quantitative (LOQ) was 3 and 10 ng mL−1, respectively. The recoveries in serum samples were between 83.54 % and 92.21 %. The method has been successfully applied to the analysis of free Neu5Ac in serum samples of pneumoconiosis patients without protein precipitation. The content of free Neu5Ac ranged within 199.9 – 235.3 ng mL−1 in healthy group and that in pneumoconiosis group ranged within 266.1 – 292.5 ng mL−1. A significant difference existed in free Neu5Ac between healthy volunteers and patients with pneumoconiosis stage I. The method can effectively remove matrix interference and enrich target analytes, and has broad application prospects in clinical detection.

Synthesis, characterization, adsorption properties and mechanism of gravity-assisted zirconium alginate hydrogel fiber for removal of methylene blue from water

In this study, zirconium alginate hydrogel fiber (ZAHF) with directional structure was prepared by gravity-assisted wet spinning method and its fabrication was confirmed by SEM, EDS, BET, XRD, FTIR and TGA. Compared with alginate materials crosslinked with divalent metal ions, Zr4+ has a strong affinity for hydroxyl groups, which further increases the content of oxygen-containing functional groups in ZAHF. Hydroxyl functional groups are considered to be important in providing adsorption sites, so ZAHF is very competitive in adsorption. Furthermore, the adsorption results shown that the synthesized ZAHF can easily adsorb methylene blue (MB) from water, and has the advantages of fast adsorption speed, large adsorption capacity and easy recycling. ZAHF can adsorb MB in a wide range of pH, and the lower the temperature, the better the adsorption performance. The actual adsorption capacity is up to 1165 mg/g at 25 ℃. Furthermore, the adsorption rate is also fast, with 79% MB quickly removed in 90 min and saturated in 240 min. Meanwhile, the maximum adsorption capacity calculated was reaches 1538 mg/g, which is much higher and faster than other adsorbents. The reusability investigation indicated that over 75% MB can be removed after five cycles. Adsorption process is spontaneous, exothermic, monolayer physical adsorption, adsorption sites on the surface of the adsorbent evenly distributed. Pores fitting, hydrogen bonding and electrostatic interaction were the main adsorption mechanisms. Meanwhile, the molecular dynamics simulation of electron density distribution proven that electrostatic interaction plays an important role in the adsorption process.

The Adsorption of VOCs by Honeycomb Ceramics Loaded with Molecular Sieves

In order to improve the adsorption performance of molecular sieve honeycomb ceramics for VOCs, the author proposes a research method for the adsorption performance of VOCs based on the honeycomb ceramics loaded with molecular sieves. The method prepared cordierite honeycomb ceramic-supported HY, Na Y, USY, ZSM-5-300, and ZSM-5-360 monolithic adsorption materials by the coating method. Using toluene, ethyl acetate, isopropanol, and acetone as adsorbates, the adsorption properties of single-component and mixed-component organic compounds on the supported molecular sieve honeycomb ceramics were investigated. The result shows ZSM-5-300 has the largest adsorption capacity for the four adsorbates, which are toluene 68.0 mg/g, ethyl acetate 118.7 mg/g, isopropanol 70.9 mg/g, and acetone 72.5 mg/g. The test results show that ZSM-5-300 molecular sieve has high saturated adsorption capacity and is an ideal VOCs adsorption material.

Manganese-based spinel adsorbents for lithium recovery from aqueous solutions by electrochemical technique

The manganese-based spinel adsorbent (HMO) refers to lithium-ion adsorbents derived from the spinel lithium manganese oxide (LMO). Two types of lithium ions extraction composite films composed of HMO (HMn2O4 and H1.6Mn1.6O4) are successfully prepared by the blade coating method. Based on the excellent Li+ selectivity of HMO and the outstanding conductivity of conductive carbon black (C), HMO/C films are carried out to extract lithium by electrochemically switched ion exchange (ESIX) technique. HMO has a certain adsorption capacity for Li+ when the Li+ concentration is close to the actual brine, and the adsorption capacity of HMn2O4 and H1.6Mn1.6O4 is 24.56 mg/g and 34.40 mg/g, respectively. HMO showed good selectivity for Li+ in multiple metal ions solution. The capacity of HMn2O4 and H1.6Mn1.6O4 keep 80% and 86% of the initial values after 5 cycles, respectively. The inherent different lithium occupied leads to the difference of electrical-adsorption abilities between HMn2O4 and H1.6Mn1.6O4. H1.6Mn1.6O4 has a broad application prospect in lithium extraction from salt lake brine due to its lower application voltage, large adsorption capacity and superior stability.

Kinetic-separation vacuum swing adsorption for safe and efficient enrichment of low concentration coal mine gas

CH4 enrichment by pressure swing adsorption (PSA) is promising to promote low-concentration coal mine gas (LC-CMG) utilization and reduce greenhouse gas emission. Here, kinetic-separation vacuum swing adsorption (VSA) preferentially adsorbing O2/N2 rather than CH4 and using low adsorption pressure was studied to overcome low separation efficiency and high explosion risk of conventional equilibrium-separation PSA for LC-CMG enrichment. The kinetic/equilibrium adsorption and breakthrough tests demonstrated that the carbon molecular sieve (CMS) adsorbent has the good O2/CH4 and N2/CH4 kinetic selectivity, which was yet restrained by the large equilibrium adsorption capacity of CH4. The LC-CMG with 4.3% CH4 and 19% O2 was enriched into the product gas containing 24.7% CH4 and 1.6% O2 with CH4 recovery of 86%, showing the excellent CH4 enrichment and deoxygenation performances of the kinetic-separation VSA. The effects of feed CH4 concentration, feed flow rate, bed length, desorption and adsorption pressures on enrichment performances such as output CH4 and O2 concentrations, CH4 recovery, productivity and specific energy consumption were analyzed, providing the optimization strategies for mitigating the negative impacts of adsorption equilibrium on kinetic separation. Finally, a numerical model was established to reveal the change of CH4 and O2 concentrations distribution with time and recognize the explosion zone in adsorption bed at adsorption and desorption stages, demonstrating the higher safety of kinetic-separation VSA than equilibrium-separation PSA. This work can guide the design of kinetic-separation VSA to achieve the safe and efficient LC-CMG enrichment.

Adsorption behaviors of triclosan by non-biodegradable and biodegradable microplastics: Kinetics and mechanism

Microplastics (MPs) pollution has been becoming serious and widespread in the global environment. Although MPs have been identified as vectors for contaminants, adsorption and desorption behaviors of chemicals with non-biodegradable and biodegradable MPs during the aging process is limited. In this work, the adsorption behaviors of triclosan (TCS) by non-biodegradable polyethylene (PE) and polypropylene (PP), and biodegradable polylactic acid (PLA) were investigated. The differences in morphology, chemical structures, crystallization, and hydrophilicity were investigated after the ultraviolet aging process and compared with the virgin MPs. The results show that the water contact angles of the aged MPs were slightly reduced compared with the virgin MPs. The aged MPs exhibited a stronger adsorption capacity for TCS because of the physical and chemical changes in MPs. The virgin biodegradable PLA had a larger adsorption capacity than the non-biodegradable PE and PP. The adsorption capacity presented the opposite trend after aging. The main adsorption mechanism of MPs relied on hydrophobicity interaction, hydrogen bonding, and electrostatic interaction. The work provides new insights into TCS as hazardous environmental contaminants, which will enhance the vector potential of non-biodegradable and biodegradable MPs.

Efficient adsorption of aflatoxin B1 from water with a reusable magnetic covalent organic framework

AbstractBACKGROUNDAflatoxin B1 (AFB1) is the most toxic and harmful aflatoxin, and has good thermal stability. Research reveals that AFB1 also exists in water, which is potentially harmful to human health. Therefore, it is urgent to remove AFB1 from water. In this work, a novel magnetic covalent organic framework composite (Fe3O4@COFs) is synthesized.RESULTSThe specific surface area is as high as 1293.32 m2 g−1. The adsorption capacity for AFB1 is 420 μg mg−1, which is six times or more that of other adsorbents. Fe3O4@COFs is employed for the adsorption and elimination of AFB1 from water. The removal efficiency is above 90% and it can be reused at least eight times. In addition, Fe3O4@COFs has been successfully used to remove trace AFB1 in actual water samples.CONCLUSIONSThe synthesized Fe3O4@COFs has good thermal stability, fast adsorption and large adsorption capacity, and can be recycled many times. Fe3O4@COFs exhibits excellent performance for the removal of AFB1, and has exceptional promise for application in water purification.© 2022 Society of Chemical Industry (SCI).

Iron Ionic Imprinted Polymers IIps for Separation and Preconcentration of Iron from Crude and Fuel Oil

A novel Iron ion-imprinted polymers (IIPs) was synthesized by bulk polymerization using different types of monomers such as 1-vinyl imidazole and Styrene, respectively. Molar ratios of monomer, template and cross-linking agent for polymerization, various monomers and solvents were studied to obtain the largest adsorption capacity for Iron. The prepared Iron-IIPs were characterized using energy dispersive X-ray spectroscopy (EDX), Fourier - transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM). The three-dimensional network structure surfaces of Iron-IIPs are unaffected by the elution procedure. Iron ions were successfully eluted from IIPs using a mixed solution from ethanol and acetic acid. The maximum adsorption capacity of Iron-IIPs was is (514.5)µmol/g for Iron-IIP1(using styrene as a monomer) and (429.1) µmol/g for Iron-IIP2(using 1-vinyl imidazole as a monomer). The adsorption by Iron-IIPs followed a Langmuir isotherm models. Solid-phase extraction (SPE) syringe packed with ionic imprinted polymers (IIPs) were used to selective separation for Iron ion from Crude or fuel oil and digest the polymer to determination the Iron by flame atomic absorption spectroscopy (FAAS) Abbreviation IIP-SPE-FAAS.

A β-ray irradiation resistant MOF-based trap for efficient capture of Th(IV) ion

Efficient capture of radionuclides from aqueous solution is highly essential for environment safety and resource recycling, but still faces large challenge. In this study, a stable aluminum-based metal–organic framework (MOF-303) with high-density ion traps was used to selectively capture thorium (Th) ion from aqueous solution. The features of aluminum center endow this material with excellent resistance from β-ray irradiation even with a high dose of 1000 kGy. Further, due to the special chelation interaction from the ion trap, MOF-303 exhibits a large adsorption capacity for Th(IV) ion (461.7 mg g−1) and excellent separation coefficients up to 97.6, 97.3 and 81.3 for Th(IV)/Pr(III), Th(IV)/Eu(III) and Th(IV)/Nd(III) respectively. The adsorption equilibrium was reached at ∼ 420 min. Besides, the regeneration of MOF-303 as well as the elution of Th(IV) ion can be achieved via an acid-wash process. Experimental and theoretical calculation results indicate Th(IV) ion can be tightly anchored in the ion trap surrounded by six active atoms, via the chemical bonding mode.