Selective Adsorption Method Research Articles

Electrospun nanofiber membrane of dibenzo 14-crown-4-ether polyimide for efficient selective lithium recovery from discarded lithium-ion batteries

To meet the growing demand for lithium resources, it is ideal to develop a green and efficient approach for recovering lithium resources from discarded lithium-ion batteries. In this work, nanofiber membranes of 14-crown-4-ether polyimide (14C4PI) (Mn = 33 kDa) with the crown ether loading of 1.38 mmol g−1 in the main chain were fabricated by electrospinning and the structure of the nanofiber membrane was regulated by tuning the electrospinning parameters. The selectivity adsorption of 14C4PI nanofiber membrane was investigated in the simulated extract of discarded lithium-ion batteries. The results showed that the 14C4PI-12 nanofiber membrane with a high specific surface area of 41.27 m2/g and a diameter of 122.7 nm was successfully prepared under the operating conditions (polymer concentration of 12 wt%, voltage of 30 kV, flow speed of 1 mL h−1, tip-to-collector of 100 mm). The 14C4PI-12 nanofiber membrane displayed a high equilibrium adsorption capacity for Li+ (Qm = 40.17 mg g−1). The adsorption of Li+ onto the membrane was proven to be monolayer chemical adsorption confirmed by adsorption kinetics and isotherm models. The calculated equilibrium adsorption rate (EAR) was up to 70 % and the complex-ratio of crown ether in 14C4PI to Li+ was 1.46:1, whose theoretical value is 1:1. Meanwhile, the selective separation factor of Li+ to Na+, K+, Mn2+, Co2+, and Ni2+ were up to 52.3, 54.97, 48.82, 41.05 and 35.04, respectively, which were much higher than that obtained from other selective adsorption method reported in literatures. The density functional theory (DFT) calculations confirm that the superior selectivity of 14C4PI to Li+ is attributed to the higher Gibbs free energy change of 14C4PI-Li+ complexation (−113.99 kcal mol−1). To sum up, this work provides an efficient method to fabricate crown ether functional polymer nanofiber membrane for recycling lithium resources.

Preparation of chitosan mesoporous membrane/halloysite composite for efficiently selective adsorption of Al(III) from rare earth ions solution through constructing pore structure on substrate

The removal of impurity Al(III) from rare earth ion solution by selective adsorption method was one of the challenging tasks. Herein, calcination and acid dissolution treatment were used to construct the pore structure for the halloysite substrate (Hal-650-H) and provide conditions for the formation of the chitosan mesoporous membrane to prepare composite (Hal-H-2CS). The selective adsorption properties and mechanism of the Hal-H-2CS for Al(III) in the rare earth ion solution were studied. The results showed that the formation of mesoporous structures for chitosan provided abundant sites for the adsorption of Al(III). Hal-H-2CS showed remarkable selective adsorption properties for Al(III) in a wide pH range and the binary mixtures with high content of Al(III) or La(III). The maximum adsorption capacity of Al(III) was 106 mg/g, while the adsorption capacity of La(III) was only 1.41 mg/g at pH 4.0. In addition, the Hal-H-2CS exhibited excellent regeneration and structural stability. The remarkable selective properties of Hal-H-2CS was achieved by the synergistic effect between chitosan mesoporous membrane and Hal-650-H, the main adsorption sites were the OH, NH2, CONH2 of chitosan and the oxygen sites of the Hal-650-H. This work provides a new strategy for the design and preparation of outstanding selective adsorbent for Al(III).

Preparation of graphene oxide enhanced magnetic composite hydrogels by one‐pot method for selective adsorption

AbstractMagnetic composite hydrogels exhibit promising prospects for diverse applications, but their mechanical properties impose limitations on their further advancement. In this study, a novel approach is proposed to directly prepare magnetic composite hydrogels utilizing nanoferroferric oxide, aiming to replace the existing preparation method. Meanwhile, graphene oxide (GO) is introduced into magnetic composite hydrogels to enhance their mechanical characteristics. By employing ammonium citrate (AC) as a dispersant, the dispersion of ferroferric oxide magnetic nanoparticles at a concentration of 40 mg/mL is achieved, enabling their coexistence with GO for the preparation of magnetic composite hydrogels. Notably, the incorporation of 3 mg/mL GO and 40 mg/mL magnetic nanoparticles in polyacrylamide (PAM) hydrogel yields remarkable improvements in maximum stress and strain, reaching 148 kPa and 496%, respectively. In contrast, magnetic composite hydrogels without GO exhibit lower values of 46.5 kPa and 351%. The presence of magnetic nanoparticles imparts magnetism to the hydrogel, with higher concentrations of magnetic nanoparticles leading to increased magnetism. Moreover, the presence of AC and GO renders the hydrogels electronegative, thereby endowing them with selective adsorption capabilities. In summary, the magnetic composite hydrogels prepared by one‐pot method have good mechanical properties and selective adsorption capacity, and have good application potential.

Synthesis of MoO3 Nanostructures by Solid State Reaction Method for Selective Adsorption of Cationic Dyes

Synthesis of MoO3 Nanostructures by Solid State Reaction Method for Selective Adsorption of Cationic Dyes

Ionic imprinted CNTs-chitosan hybrid sponge with 3D network structure for selective and effective adsorption of Gd(III)

From economical and environmental standpoint, it is very meaningful for selective recovery of Gd(III) via adsorption from the real waste solution. At present, conventional adsorbents are impeded by poor adsorption capacity, low selectivity, complicated preparation and eco-pollution. To this end, a novel imprinted CNTs-chitosan hybrid sponge (COOH-CNTs/CS-IIS) with 3D network structure was fabricated via easy polymerization-lyophilization method for selective adsorption of Gd(III). The imprinting sites dispersing on the surface of channels in COOH-CNTs/CS-IIS can achieve the selective adsorption to Gd(III) and improve adsorption capacity. The combining of biomass chitosan sponge with oxidized CNTs not only further enhances the adsorption capacity and mechanical strength of COOH-CNTs/CS-IIS but also actualizes its rapid retrieval by the squeeze of elastic sponge. Systematic adsorption tests indicate that COOH-CNTs/CS-IIS has a maximum adsorption capacity of 71.95 mg g−1, and can adsorb 88.9% of the ultimate adsorption within 60 min. The selectivity tests show that COOH-CNTs/CS-IIS exhibits preferential adsorption for Gd(III) with a distribution coefficient of 0.656 L g−1. Furthermore, COOH-CNTs/CS-IIS has excellent regeneration performance. Considering its cost-effectiveness, eco-friendliness, user-friendliness, easy preparation and favorable adsorption performance, COOH-CNTs/CS-IIS holds great promise in selective recovery of Gd(III) from the real waste solution.

Remarkable effect of deprotonation on adsorption of 3-MCPD and glycidol on carboxylated Fe-MIL-88s

A selective adsorptive method using metal-organic frameworks (MOFs) was employed for removal of 3-MCPD and glycidol, which are potential genotoxic carcinogens. To optimize adsorption performance, a series of Fe-MIL-88 s with different ligand types were used with further modification by sequential carboxylation and deprotonation processes. Among these ligands, the MOFs, consisting of 2,6-naphthalenedicarboxylic acid (Fe-MIL-88_BDC) showed the best adsorption performance. A rapid efficiency improvement of 3-MCPD and glycidol was observed after its surface modification. Despite lacking superior porosity, deprotonated Fe-MIL-88_BDC showed the highest adsorption capacity of the reported adsorbents. We found that the remarkable improvement in adsorption efficiency was due to esterification with carboxyl groups on 3-MCPD and glycidol. This adsorption performance was seen only in 3-MCPD ester and glycidyl ester (as a precursor of 3-MCPD and glycidol) in palm oil without a change of fatty composition and minor components.

Desulfurization of Spent Tire Pyrolysis Oil and Its Distillate via Combined Catalytic Oxidation using H2O2 with Formic Acid and Selective Adsorption over Al2O3

This paper reports an experimental investigation into the desulfurization of a spent tire pyrolysis oil and its distillate using a combined catalytic oxidative and selective adsorption method. The ...

Preparation of Crown‐Ether‐Functionalized Polysulfone Membrane by In Situ Surface Grafting for Selective Adsorption and Separation of Li+

AbstractIn order to develop an effective and environment‐friendly method for selective adsorption of Li+, a recyclable polysulfone surface graft 4‘‐aminobenzo‐12‐crown‐4‐ether (PSf‐sg‐AB12 C4) membrane was prepared via non‐solvent induced phase separation method and in situ surface grafting through nucleophilic substitution. The surface chemical compositions and the morphologies of the PSf‐sg‐AB12 C4 were systematically verified by X‐ray photoelectron spectra (XPS) and scanning electron microscopy (SEM). The dynamic adsorption process of PSf‐sg‐AB12 C4 for Li+ was well described by the pseudo‐second‐order kinetics model, and the maximum equilibrium adsorption capability was 51.99 mg⋅g‐1. Moreover, the PSf‐sg‐AB12 C4 membrane displayed good selectivity for Li+, meanwhile the selective separation factors (α) of Li+ to K+, Na+, Ca2+ and Mg2+ were 38.43, 33.13, 27.11 and 3.42, respectively. These selective adsorption results were verified by the density functional theory (DFT) calculations. Additionally, the regenerated adsorption amount of the PSf‐sg‐AB12 C4 toward Li+ after 10 cycles of adsorption/desorption was 90.37% of initial adsorption cycle.

Surface molecular imprinting on carbon microspheres for fast and selective adsorption of perfluorooctane sulfonate

Perfluorooctane sulfonate (PFOS) is a persistent organic pollutant with high biological and chemical stability. It is important to develop fast and selective adsorption method for PFOS wastewater treatment. In this study, novel molecularly imprinted polymer (MIP) for PFOS adsorption was prepared. To obtain rapid adsorption kinetics, the MIP has been designed as the surface polymer using the carbon microsphere as carrier (MIP-CMSs). To ensure high adsorption selectivity to the template, two monomers with different functional structures, namely methacryloyloxyethyl trimethyl ammonium chloride (DMC) and 2-(trifluoromethyl)acrylic acid (TFMA), were employed as bi-functional monomers. The structure and morphology of MIP-CMSs were characterized using field emission scanning electron microscopy with the energy dispersive spectrometer, transmission electron microscopy, and Fourier transformation infrared spectroscopy. Based on the adsorption experiments, it was concluded that MIP-CMSs had specific binding property for PFOS on acidic condition. The adsorption equilibrium time was 1h, while the adsorption capacity was 75.99 mg g−1 at pH 3. Coexistence with contaminants with different structures had little influence on the selectivity for PFOS. The spent MIP-CMSs could be regenerated by the methanol and acetic acid mixed solution. The electrostatic interaction and molecular size played important roles in recognizing the target compound in the adsorption process.

Selective adsorption of 4-chlorophenol based on silica-ionic liquid composite developed by sol–gel process

A new high performance composite (SiO2-ClPrNTf2) was synthesized by the sol–gel method for selective adsorption of 4-chlorophenol (4-CP) contaminated aqueous media prior to its determination by use of high performance liquid chromatography. Results demonstrated that SiO2-ClPrNTf2 composite had significant properties involving high surface area and static uptake capacity, which offered adsorbent features that enhanced the direct solid phase adsorption toward the target compounds for the selective detection of 4-CP. Isotherm and kinetic models were systematically studied to evaluate the analytical efficiency of the SiO2-ClPrNTf2 composite toward 4-CP by employing a batch adsorption technique at optimum conditions. The maximum static adsorption capacity was identified to be 626.25mgg−1 at pH 1.0, providing that the adsorption capacity of 4-CP was improved by 96.86% with the SiO2-ClPrNTf2 composite as compared to native silica. Data obtained from adsorption isotherm models verified that Langmuir adsorption isotherm model was best described the 4-CP adsorption process. Moreover, data of 4-CP adsorption on SiO2-ClPrNTf2 composite as a function of contact time displayed that equilibrium kinetics were very fast and obeyed a pseudo second-order kinetic model. Finally, the efficiency of the methodology was confirmed by applying it to real water samples with satisfactory results.

Arsenic removal from aqueous system using modified chestnut shell

Natural adsorbent chestnut shell treated with FeCl3 was prepared and employed by means of batch method for selective adsorption and removal of arsenic from aqueous system. The influences of different parameters, such as contact time, pH, temperature, and concentration of adsorbate, on adsorption performance of chestnut shell treated with FeCl3 was studied in order to optimize the adsorption conditions. Batch adsorption studies have shown that removal capacity of chestnut shell can be increased by FeCl3 treatment. The maximum adsorption capacity was found to be 0.885 mg g−1 As(III) of chestnut shell, which was treated with FeCl3. The adsorption data obtained follow a first-order rate expression and fit the Freundlich isotherm that has been used to obtain the thermodynamic parameters. In addition, the thermodynamic parameters, such as standard free energy (ΔG°), standard enthalpy (ΔH°), and standard entropy (ΔS°), of the adsorption process were calculated. It was found that the adsorption of arsenic on chestnut shell was exothermic. The adsorbents were characterized by scanning electron microscopy.

Preparation and Properties of Magnetic Molecularly Imprinted Polymers and Their Use as Adsorbents for Selective Adsorption of Indole

A novel method for selective adsorption of indole using magnetic molecularly imprinted polymers (MMIPs) as the adsorbent is proposed in this work. The MMIPs were synthesized by microemulsion polymerization, using Fe3O4 nanoparticles as the magnetically susceptible component, acrylamide as the functional monomer, ethylene glycol dimethacrylate as the cross-linker and indole as template molecule. The products obtained were characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, vibrating sample magnetometry and thermogravimetric analysis. The adsorption performances of MMIPs were investigated by batch adsorption experiments in terms of selective recognition, adsorption kinetics and adsorption isotherms, respectively. The maximum amount of adsorption on MMIPs occurs at approximately 120 minutes. The results indicate that MMIPs possess high adsorption capacity for indole. The adsorption fits with the pseudo-second-order kinetic model and the Langmuir isotherm model.

Activated carbon immobilized dithizone phase for selective adsorption and determination of gold(III)

Abstract A simple method for selective adsorption and determination of gold(III) based on activated carbon immobilized dithizone (AC-DTZ) phase combined with inductively coupled plasmaoptical emission spectrometry was developed. Surface properties of the new hemically modified AC-DTZ phase were confirmed by Fourier transform infrared spectroscopy. The effect of pH on the selectivity of AC-DTZ towards eight metal ions, including Au(III), Cd(II), Co(II), Cu(II), Fe(III), Ni(II), Pb(II) and Zn(II), was investigated. Based on the pH study, it was found that the selectivity of AC-DTZ phase was the most towards Au(III). For a deeper mechanistic understanding of the analytical potential of the AC-DTZ phase towards Au(III), other factors influencing the maximum uptake of Au(III) on AC-DTZ were also investigated. The results showed that the adsorption capacity for Au(III) was improved by 64.07% with the AC-DTZ phase as compared to the carboxylic acid derivative of activated carbon after only 1 h contact time. Adso...

Selective Adsorption and Determination of Hexavalent Chromium in Water Samples by Chemically Modified Activated Carbon with Tris(hydroxymethyl)aminomethane

This study introduces a sensitive and simple method for selective adsorption of hexavalent chromium, Cr(VI), from water samples prior to its determination by inductively coupled plasma optical emission spectrometry (ICP-OES). The method utilized activated carbon modified with tris(hydroxymethyl)aminomethane (AC-TRIS) as an adsorbent. Surface properties of the new chemically modified AC-TRIS phase were confirmed by Fourier transform infrared (FTIR) spectroscopy. Seven metal ions, including Co(II), Cu(II), Ni(II), Pb(II), Cr(III), Cr(VI), and Fe(III) were evaluated and determined at different pH values (1.0–8.0), except for Fe(III) at pH values (1.0–4.0). Based on the results of the effect of pH on adsorption of these metal ions on AC-TRIS, Cr(VI) was selected for the study of other parameters controlling its maximum uptake on AC-TRIS under batch conditions and at the optimum pH value 1.0. The maximum static adsorption capacity of Cr(VI) onto the AC-TRIS was found to be 43.30 mg g−1 at this pH and after 1 hour contact time. The adsorption data of Cr(VI) were modeled using both Langmuir and Freundlich classical adsorption isotherms. Results demonstrated that the adsorption of Cr(VI) onto AC-TRIS followed a pseudo second-order kinetic model. In addition, the efficiency of this methodology was confirmed by applying it to real environmental water samples.

Selective Adsorption of Dibenzothiophene Using Magnetic Molecularly Imprinted Polymers

In this study, a novel and quick method for selective adsorption of dibenzothiophene (DBT) from gasoline using magnetic molecularly imprinted polymers (MMIPs) as the adsorbent has been employed. The MMIPs were prepared by a surface molecular imprinting technique, using Fe3O4 magnetite nanoparticles as a magnetically susceptible component, DBT as template molecule, 4-vinylpyridine (4-VP) as functional monomer and ethylene glycol dimethacrylate (EGDMA) as cross-linker. The synthetic MMIPs were characterized by Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM). The adsorption performances of MMIPs were investigated by batch adsorption experiments in terms of adsorption kinetics, isotherms and selective recognition. The results of the study indicated that MMIPs were able to adsorb DBT well, the adsorption equilibrium time was about 5 h and the equilibrium adsorption amount was 22.23 mg/g at 318 K. In the corresponding selectivity test, ...

Arsenic removal from aqueous system using natural and modified (Kula ebonite and zeolite) adsorbents

AbstractNatural adsorbents (Kula ebonite, zeolite and zeolite treated with Al2(SO4)3; Al2(SO4)3+NaOH; FeCl3 and FeCl3+NaOH) were prepared and employed by means of batch method for selective adsorption and removal of arsenic from aqueous system. The influences of different parameters such as, contact time, pH, temperature, and concentration of adsorbate on adsorption performance of zeolite and zeolite treated with FeCl3 and FeCl3+NaOH were studied in order to optimize the adsorption conditions. Batch adsorption studies have shown that removal capacity of zeolite from aqueous solutions can be increased by FeCl3 and FeCl3+NaOH treatment. The maximum adsorption capacities were 1.99 and 3.43 mg g−1 of zeolite which was treated with FeCl3 and FeCl3+NaOH for arsenic, respectively. The adsorption data obtained follows a first‐order rate expression and fits the Langmuir isotherm that has been used to obtain thethermodynamic parameters. In addition, the thermodynamic parameters, standard free energy (ΔG°), standard enthalpy (ΔH°), standard entropy (ΔS°) of the adsorption process were calculated. It was found that the adsorption of arsenic on zeolite was exothermic. © 2011 American Institute of Chemical Engineers Environ Prog, 2011

Selective adsorption of hydrocarbon-oxidizing Rhodococcus cells in a column with hydrophobized poly(acrylamide) cryogel

A method for selective adsorption of Rhodococcus cells in the column with hydrophobized poly(acrylamide) cryogel (cryoPAAG) was developed that allowed rhodococci separation from mixed bacterial populations and their effective concentration within a sponge-like gel matrix. Hydrophobization of cryoPAAG using the n-dodecane graft (C 12) was performed to enhance the adhesion of Rhodococcus cells to the cryogel; this was suggested by our finding that alkanotrophic rhodococci possess high adhesive activity (91–98%) towards n-alkanes, whereas other Gram-positive and Gram-negative bacteria tested did not adhere strongly to hydrocarbons. The selective index of the hydrophobic C 12-cryoPAAG column for Rhodococcus cells was 72% that ensured their separation from complex bacterial cultures. Respirometry results using the Columbus Micro-Oxymax® respirometer showed that the maximal respiratory activity of C 12-cryoPAAG-immobilized Rhodococcus cells incubated with petroleum hydrocarbons was 1.6–1.8 times higher than that of freely suspended cells, and this correlated with the largest immobilized cell number. Moreover, high respiration rates were maintained over 3 weeks of incubation, indicating a considerable functional stability of the cryoPAAG-immobilized biocatalyst developed.

Separation and Immobilization of Lipase from Penicillium simplicissimum by Selective Adsorption on Hydrophobic Supports

Lipases are an enzyme class of a great importance as biocatalysts applied to organic chemistry. However, it is still necessary to search for new enzymes with special characteristics such as good stability towards high temperatures, organic solvents, and high stereoselectivity presence. The present work's aim was to immobilize the lipases pool produced by Penicillium simplissicimum, a filamentous fungi strain isolated from Brazilian babassu cake residue. P. simplissicimum lipases were separated into three different fractions using selective adsorption method on different hydrophobic supports (butyl-, phenyl-, and octyl-agarose) at low ionic strength. After immobilization, it was observed that these fractions' hyperactivation is in the range of 131% to 1133%. This phenomenon probably occurs due to enzyme open form stabilization when immobilized onto hydrophobic supports. Those fractions showed different thermal stability, specificity, and enantioselectivity towards some substrates. Enantiomeric ratio for the hydrolysis of (R,S) 2-O-butyryl-2-phenylacetic acid ranged from 1 to 7.9 for different immobilized P. simplissicimum lipase fractions. Asymmetry factor for diethyl 2-phenylmalonate hydrolysis ranged from 11.8 to 16.4 according to the immobilized P. simplissicimum lipase fractions. Those results showed that sequential adsorption methodology was an efficient strategy to obtain new biocatalysts with different enantioselectivity degrees, thermostability, and specificity prepared with a crude extract produced by a simple and low-cost technology.

Partial characterization of a class IIa pediocin produced by Pediococcus parvulus 133 strain isolated from meat (Mexican “chorizo”)

Pediocin-like bacteriocins are antimicrobial substances produced by some bacteria with high antilisterial activity. Several isolates of Pediococcus acidilactici and two Pediococcus parvulus strains of vegetable origin have been reported to produce this kind of peptide. This work presents the partial characterization of the bacteriocin produced by P. parvulus 133 found in meat and confirms its identity as a heat resistant, antilisterial bacteriocin. This peptide has a relatively narrow inhibitory spectrum but a high antilisterial activity. Pediocin remained active after heating to 121 °C, but its thermoresistance varied with pH. The pH selective adsorption method resulted in a 150-fold concentration of antimicrobial activity. The final extract was obtained by ultrafiltration and resulted in an additional 10-fold concentration of activity. Molecular weight was estimated as 5 kDa and isoelectric point was 8.65. The sequence of the first 17 aminoacids at the N-terminal end of the bacteriocin showed complete coincidence with that previously reported for pediocin A1 (AcH) and with an antilisterial peptide produced by Bacillus coagulans. High sequence similarity was also found with two other antilisterial bacteriocins.

Specific Determination of Sucrose in Honey

Abstract This paper describes a procedure for determining sucrose in honey without its preliminary separation. Interference from the large excess of glucose is removed by treating with glucose oxidase-catalase, and then the glucose from invertase hydrolysis of sucrose is measured. Sucrose is difficult to measure in honey because of its low concentration and the presence of at least 24 other sugars. Standard deviation between duplicates for 50 honey samples containing from 0.06 to 10.6% sucrose was 0.19; no known honey sugars interfered. The selective adsorption method for separating sucrose from interfering oligosaccharides is too slow for repetitive analysis of honey for sucrose only, although it is 8 times more sensitive than the procedure described. Results of analysis of 13 honey samples for sucrose by this procedure (averaging 1.66%) and the selective adsorption method (averaging 1.59%) did not differ significantly.