Fibrous Adsorbent Research Articles

Synthesis of a functionalized fibrous adsorbent of high uptake capacity: a study on Pb(ii) uptake and simple acidic site model development

Development and exposure of acidic functional groups on lignocellulose biomaterials through destruction of lignin barrier by acid treatment.

Facile preparation of amidoxime-functionalized fiber by microwave-assisted method for the enhanced adsorption of chromium(vi) from aqueous solution

In this study, a facile and highly efficient approach, the microwave-assisted (MW-aid) method, was applied for the synthesis of amidoxime-functionalized fibrous adsorbent, which exhibited enhanced adsorption capacities for Cr(vi) in aqueous solution.

Radiation synthesis of a new amidoximated UHMWPE fibrous adsorbent with high adsorption selectivity for uranium over vanadium in simulated seawater

A new kind of highly efficient adsorbent material has been fabricated in this study for the purpose of extracting uranium from seawater. Ultra-high molecular weight polyethylene (UHMWPE) fiber was used as a trunk material for the adsorbent, which was prepared by a series of modification reactions, as follows: (1) grafting of glycidyl methacrylate (GMA) and methyl acrylate (MA) onto UHMWPE fibers via Co-60 gamma-ray pre-irradiation; (2) aminolyzation of UHMWPE fiber by the ring-opening reaction between of epoxy groups PGMA and ethylene diamine (EDA); (3) Michael addition of amino groups with acrylonitrile (AN) to yield nitrile groups; (4) amidoximation of the attached nitrile moieties by hydroxylamine in dimethyl sulfoxide-water mixture. Modified UHMWPE fibers were characterized by means of attenuated total reflectance-Fourier transformed infrared spectroscopy (ATR-FTIR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM) to confirm the attachment of amidoxime (AO) groups onto the UHMWPE fibers. The results of X-ray diffraction (XRD) and single fiber tensile strength verified that the modified UHMWPE fiber retained excellent mechanical properties at a low absorbed radiation dose. The adsorption performance of the UHMWPE fibrous adsorbent was evaluated by subjecting it to an adsorption test in simulated seawater using a continuous-flow mode. The amount of uranium adsorbed by this AO-based UHMWPE fibrous adsorbent was 1.97 mg-U/g after 42 days. This new adsorbent also showed high selectivity for the uranyl ion, and its selectivity for metal ions was found to decrease in the following order: U > Cu > Fe > Ca > Mg > Ni > Zn > Pb > V > Co. The adsorption selectivity for uranium is significantly higher than that for vanadium. In addition, preparation of this modified adsorbent consumes much smaller amounts of the toxic acrylonitrile monomer than the conventional preparation methods of AO-based polyethylene fibers. (C) 2016 Published by Elsevier Ltd.

Preparation of Amidoximated Ultrahigh Molecular Weight Polyethylene Fiber by Radiation Grafting and Uranium Adsorption Test

An ultrahigh molecular weight polyethylene (UHMWPE) fibrous adsorbent with amidoxime (AO) groups, denoted as AO-UHMWPE, was prepared by preirradiation-induced graft copolymerization of acrylonitrile (AN) and acrylic acid (AA) on UHMWPE fibers, followed by amidoximation. The chemical structure, thermal stability, and mechanical strength were evaluated by means of Fourier transform infrared spectrometry, thermogravimetric analysis, and tensile tests, respectively. The adsorption behaviors of the AO-UHMWPE fiber were studied by batch adsorption in 331 ppb uranium solution, and flow-though adsorption experiments in simulated and natural seawater. It was found that the adsorption conditions (i.e., contact time and manner, temperature, and uranyl ion initial concentration) significantly influence the amount of uranyl ions binding to the AO-UHMWPE fibers. The adsorption of uranium in the batch adsorption experiment was 4.54 g-U/kg-ad in the presence of massive amounts of interference ions.

Evaluation of boron adsorption on new radiation grafted fibrous adsorbent containing N‐methyl‐D‐glucamine

AbstractBACKGROUNDThe performance of newly prepared fibrous boron selective adsorbent was investigated via equilibrium isotherms, kinetics and thermodynamics of boron adsorption from aqueous solutions. The adsorbent was obtained by radiation induced graft copolymerization (RIGC) of vinyl benzyl chloride (VBC) onto nylon‐6 fibers followed by chemical treatment with N‐methyl‐D‐glucamine (NMDG).RESULTSThe effect of solution pH on the boron adsorption capacity was investigated. The equilibrium adsorption data was fitted to the Langmuir, Freundlich and Redlich–Peterson isotherms, with the experimental data best fitting the Redlich–Peterson model. The kinetic data analyzed using the intra‐particle diffusion model indicated that adsorption onto the fibrous chelating adsorbent is governed by a film diffusion mechanism. The thermodynamic adsorption parameters including the Gibb's free energy change (ΔGo), enthalpy change (ΔHo) and entropy change (ΔSo) were determined and the results indicated that adsorption onto the fibrous adsorbent occurs spontaneously.CONCLUSIONThe high adsorption capacity and rapid kinetics suggest that the newly prepared fibrous adsorbent could have strong potential for boron removal from aqueous solutions. © 2015 Society of Chemical Industry

Resource recovery of Cr(VI) from electroplating wastewater: Laboratory and pilot-scale investigation using fibrous weak anion exchanger

The efficient removal of Cr(VI) was investigated using fibrous ion exchange material as the adsorbent. The breakthrough and operating exchange capacities, elution and regeneration, as well as the influence factors toward the recovery of Cr(VI), were systematically evaluated. The results showed that the novel fibrous adsorbent possessed high operating capacity for Cr(VI) (approximately 400 mg/g for chromate solution, and 160–230 mg/g for various electroplating wastewater), excellent kinetic behavior (fed flow rate: 10 mL/(g min)), minor capacity losses (approximately 20%) after 80 adsorption–elution cycles. Based on above laboratory results (Q = 0.6–1.0 L/h), the resource recovery process of Cr(VI) from electroplating wastewater was developed through the pilot-scale multi-column facility (Q = 600 L/h). By the saturated adsorption and multiple-use of eluent, the chromate could be selectively enriched even from the electroplating wastewater containing SO42− and Cl− species. The concentration and purity of eluent were obviously enhanced, and could be reused in the electroplating industry.

Chromatographic Characterization and Process Performance of Column-Packed Anion Exchange Fibrous Adsorbents for High Throughput and High Capacity Bioseparations

Fibrous materials are prominent among novel chromatographic supports for the separation and purification of biomolecules. In this work, strong anion exchange, quaternary ammonium (Q) functional fibrous adsorbents were evaluated with regards to their physical and functional characteristics. A column packed with Q fibrous adsorbent illustrated the good column packing efficiency of theoretical plate height (H) values and higher permeability coefficients (>0.9 × 10−7 cm2) than commercial adsorbents. For pulse experiments with acetone and lactoferrin as tracers under nonbinding conditions, the total porosity (for acetone) and the interstitial porosity (for lactoferrin) measured 0.97 and 0.47, respectively. The total ionic capacity of the chemically-functionalized Q fiber was 0.51 mmol/mL. The results indicated that the Q fiber had a static binding capacity of 140 mg/mL and a dynamic binding capacity (DBC) of 76 mg/mL for bovine serum albumin (BSA) and showed a linearly-scalable factor (~110 mL) for a column volume with high capacity and high throughput. Furthermore, this adsorptive material had the ability to bind the high molecular weight protein, thyroglobulin, with a capacity of 6 mg/mL. This work demonstrated the column-packed Q fibrous adsorption system as a potential chromatography support that exhibits high capacity at higher flow rates.

Preparation, characterization and application of a novel silane-bridged polyaniline/cotton fiber composite

A silane-bridged polyaniline (PANI)/cotton fiber (CF) composite (designated as PANI/SCF) was prepared by a novel and facile approach in the current study. Aniline-bearing silane molecules were first grafted onto the CF surface through a condensation reaction between hydroxyl groups of cellulose and the silane molecules. Subsequent oxidative polymerization of aniline in the presence of silane-modified CF (SCF) yielded the final PANI/SCF composite, which can be used as the potential Cr(VI) adsorbent. Results showed that the optimal silane grafting conditions were: 0.01mol/L HAc, EtOH/water volume ratio 95/5, reaction temperature 40°C and silane dosage 0.1g (per 0.5g CF). Using SCF that prepared under the optimal conditions as the substrate, about 4.6% of PANI can be deposited, mostly existing as nanorods and distributing more evenly than those on the raw CF surface. FTIR and XPS analyses further testified the successful chemical bonding of silane and the final deposition of PANI on the fiber surfaces. In comparison with neat PANI, the solid–liquid separation can be achieved by simply taking the fibrous adsorbent out. Besides, the adsorption capacity of PANI/SCF on the basis of PANI mass (dividing Qm by PANI content) was much higher, probably due to the uniform distribution of PANI nanostructures on SCF and the high efficiency of PANI nanostructures in Cr(VI) adsorption.

Radiation grafted adsorbents for newly emerging environmental applications

Abstract Radiation induced grafting (RIG) is acquired to prepare a number of adsorbents for newly emerging environmental applications using a single route involving RIG of glycidymethacrylate (GMA) onto polyethylene–polypropylene (PE–PP) non-woven fabric. The grafted fabric was subjected to one of three functionalization reactions to impart desired ionic characters. This included treatment with (1) N -dimethyl- d -glucamine, (2) triethylamine and (3) triethylamine and alkalisation with KOH. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM) were used to study the changes in chemical and physical structures of the obtained fibrous adsorbents. The potential applications of the three adsorbents for removal of boron from solutions, capturing CO 2 from CO 2 /N 2 mixtures and catalysing transesterification of triacetin/methanol to methyl acetate (biodiesel) were explored. The obtained fibrous adsorbents provide potential alternatives to granular resins for the investigated applications and require further development.

Preparation and characterization of grafted cellulosic fibers and their applications in protein purification

Fibrous adsorbents were subjected either to chemical treatment or gamma irradiation to introduce epoxide groups onto their cellulosic backbone using glycidyl methacrylate. These epoxide moieties were modified to have diethylaminoethanol (DEAE) as well as quaternary ammonium (Q) functionalities. The resulting anion-exchange adsorbents were characterized by their FTIR spectra and ionic capacities. The fiber-based adsorbent systems showed similar packing efficiency to the commercially available adsorbents, where the Péclet number values were ⩾60, suggesting near-plug-flow conditions. The total ionic capacities obtained for these chemically grafted adsorbents were ca. 400mmol/L. These adsorbents showed dynamic binding capacities (DBC) of ca. 48mg/mL for bovine serum albumin (BSA). Protein binding capacities obtained from chemical grafting initiation techniques were 18-fold-higher than radiation-induced techniques. The advantage of these adsorbents lies in their high operational flow rates while maintaining their high binding capacities.

A novel lead ion‐imprinted chelating nanofiber: Preparation, characterization, and performance evaluation

ABSTRACTA novel Pb(II) ion‐imprinted chelating nanofibers (nIIP), synthesized by combining electrospinning with surface ion imprinting technique, was reported in this study. nIIP was characterized with Fourier transmission infrared spectrometry and scanning electron microscopy, respectively. The performance of nIIP for Pb(II) sorption was conducted through a batch adsorption experiments. Experimental data showed that adsorption capacity of nIIP was much higher than that of non‐ion imprinted chelating acrylic microfibers (mNIP) derived from commercial available acrylic microfibers, and adsorption behaviors agreed well with pseudo‐second‐order kinetic and Langmuir isotherm model. The values of Gibbs free energy change derived from experimental data suggested that the adsorption Pb(II) on nIIP is spontaneous and favorable at high temperature. In addition, nIIP had the highest selectivity among three tested fibrous adsorbents for Pb(II) from binary metal solution, the selectivity coefficients for Pb(II) from binary metal solution of Pb(II)/Cu(II), Pb(II)/Ni(II), and Pb(II)/Cd(II) onto nIIP were 47, 101, and 162, respectively. Besides, a forty adsorption/desorption cycles revealed that nIIP was a promising recyclable adsorbent. In conclusion, the novel nIIP is a highly effective adsorbent for enrichment and separation of Pb(II) in the presence of competitive ions in aqueous solution, and it is potential to be applied for recovering metals from heavy metal polluted industrial wastewater such as Pb(II)/Cd(II), Pb(II)/Ni(II), and Pb(II)/Cu(II) polluted wastewater. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41507.

Linear and Non-Linear Regression Analysis of Boron Adsorption Kinetics on New Radiation Grafted Fibrous Adsorbent

The kinetic behavior of a new adsorbent prepared by radiation induced grafting of vinyl benzyl chloride (VBC) onto nylon-6 fibers followed by functionalization with N-methyl-D-glucamine was investigated using pseudo second-order kinetic model. The linear method and non-linear regression methods were compared to determine the best fitting for the kinetic model describing the adsorption of boron by the new adsorbent. Four pseudo second-order kinetic linear equations were presented. A type-1 pseudo second-order linear method was found to fit best the experimental data. Non-linear regression method was found to be more appropriate to describe the boron adsorption by the fibrous adsorbent which has also shown fast kinetics.

Synthesis of Highly-Selective Fibrous Adsorbent by Introducing 2-Ethylhexyl Hydrogen-2-Ethylhexylphosphonate for Scandium Adsorption

2-ethylhexyl hydrogen-2-ethylhexylphosphonate (EHEP) is commonly used as a metal extractant because it has a particular affinity for rare-earth metals like Scandium (Sc). To develop a highly-selective adsorbent of Sc(III), EHEP was introduced as a functional group onto a polyethylene fabric with radiation-induced graft polymerization(RIGP). The adsorption performances for Sc(III) were evaluated with aqueous solutions containing Sc(III) and Fe(III) in bath and column tests. As a result of column test, the adsorption capacities of Sc(III) and Fe(III) until the bed volume reached 5000 were 5.22 and 0.12 mg/g, respectively. It means that the amount of collected Sc(III) by the EHEP adsorbent was approximately 44 times higher than that of Fe(III). These results indicate that the grafted adsorbent containing EHEP has an extremely high selectivity for Sc(III) adsorption.

Amine functionalized radiation-induced grafted water hyacinth fibers for Pb2+, Cu2+ and Cr3+ uptake

An amine group containing fibrous adsorbent was prepared by reaction of grafted water hyacinth fibers with ethylenediamine. Glycidyl methacrylate (GMA) was grafted onto water hyacinth fibers using gamma radiation induced graft polymerization through simultaneous grafting technique and this was used as base material for producing the amine type adsorbents. The conversion of the epoxy group from GMA into amine group was investigated. The concentration of ethylenediamine solution that gave the highest amine functional group density was 50% by volume in 2-propanol. The amine functionalized water hyacinth fibers were characterized using Attenuated Total Reflectance-Fourier Transformed Infrared Spectroscopy (ATR-FTIR), Thermogravimetric Analysis (TGA), and Energy Dispersive X-ray Spectroscopy (EDX). Information derived from these analyses confirms the successful conversion of the epoxy group. The amine-type adsorbent was evaluated for its uptake of Pb2+, Cu2+ and Cr3+ from aqueous solutions. The initial concentration of the metal ions and pH of the solutions were found to influence the amount of metal ions adsorbed by the amine-type adsorbent. The kinetics of adsorption was observed to follow Lagergren's first order equation. Results of ion sorption studies indicate that gamma radiation-induced grafting and subsequent chemical modification improved the ion sorption behaviour of water hyacinth fibers.

Preparation and characterization of polyphenylene sulfide-based chelating fibers

A series of novel chelating fibers containing sulfur, nitrogen, oxygen heteroatoms were prepared via the functionalization of chloromethylated polyphenylene sulfide (CMPPS). The structures, micromorphology and physicochemical properties of these fibrous adsorptive materials were characterized by FT-IR, elementary analysis, TG and SEM–EDS. The results show that chelating fibers had high functional group contents (3.94 mmol/g for thiourea, 3.85 mmol/g for mercapto, 5.00 mmol/g for methylamine and 6.07 mmol/g for ethylenediamine, respectively). Owing to the unique matrix of polyphenylene sulfide fiber, these fibrous adsorbents possess excellent thermostability. This synthetic method proved a simple and efficient way for the preparation of chelating fibers.

Preparation of a solid amine adsorbent based on polypropylene fiber and its performance for CO2 capture

Abstract

Properties and evaluation of amidoxime-based UHMWPE fibrous adsorbent for extraction of uranium from seawater

An amidoxime-based ultra-high molecular weight polyethylene (UHMWPE) fibrous adsorbent was successfully prepared by γ-irradiation-induced graft copolymerization of acrylonitrile (AN) and acrylic acid (AA), followed by amidoximation. The grafting of AN and AA on the UHMWPE fiber and the amidoximation of the grafted fiber were confirmed by Fourier transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis. The mechanical property of the original and modified UHMWPE fibers was compared by single-filament strength test. The adsorption property of the UHMWPE fibrous adsorbent was evaluated by adsorption test in uranyl nitrate solution and seawater. The surface of the modified UHMWPE fibers was covered by the grafting layer and became rough. The tensile strength of the amidoxime-based UHMWPE fibrous adsorbent was influenced by the absorbed dose and hydrochloric acid elution, but was independent of the grafting yield and amidoximation. The uranium adsorption amount of the amidoxime-based UHMWPE fibrous adsorbent after immersing in seawater for 42 days was 2.3 mg-U/g.

Design of a viscose based solid amine fiber: Effect of its chemical structure on adsorption properties for carbon dioxide

A solid amine fiber VF–AM–TETA was designed with viscose (VF) substrate for efficient CO2 capture, where its hydroxyl groups could serve synergizing effect in CO2-amine reaction. When grafting modification and subsequent amination were applied to VF, effect of structures of grafting monomers as well as amines on its CO2 adsorption properties was taken into account. Amines with different 1° and 2° amine ratios were investigated as amination agents in terms of amine efficiency, so as to afford the fibrous adsorbent with maximum effective reactive amine sites for CO2 capturing. Results suggested that higher content in primary amine can facilitate CO2 adsorption onto the fiber by stronger basicity and smaller steric hindrance. Consequently, optimal chemical structure provided VF–AM–TETA with satisfactory adsorption capacity of 4.08mmol/g when amine content was 8.74mmol/g. Constant adsorption behavior within 6 adsorption–desorption cycles indicated its desirable regeneration performance in practical use due to excellent mechanical properties of VF–AM–TETA.

Potential of fibrous adsorbents for the binding and characterization of Porphyridium purpureum bioactive polysaccharides

AbstractBACKGROUNDComplex polysaccharides are important in the pharmaceutical industry, yet, due to their large molecular weight and reduced charges, their purification is a highly demanding process that requires binding matrices with unique properties. This work demonstrates for the first time that complex polysaccharides biosynthesized by microalga Porphyridium purpureum can be adsorbed onto Q fibrous anion exchangers.RESULTSWhen the polysaccharides were characterized, the extent of sulfation was higher in native polysaccharides than in ethanol‐ or alkali‐extracts. The zeta potentials increased with increasing pH and the highest charge was observed at pH 8, while the Z‐average diameters of the polysaccharide at pH 6 were highest for alkali‐extracts. Instead of pellicular resins, Q fibrous adsorbents were used to determine Langmuir thermodynamic properties and dynamic binding capacities. The parameters included static binding capacity and dissociation constant of 13.47 ± 1.02 mg g‐1 and 0.141 ± 0.027 mg mL‐1, and 10 and 50% breakthrough capacities of 4.46 ± 0.22 and 5.51 ± 0.28 mg g‐1, respectively. The antiviral activity of the polysaccharides was demonstrated by minimizing bacteriophage lysis of Streptococcus thermophilus.CONCLUSIONThis work demonstrates that polysaccharide extraction can be optimized and the adsorption and desorption of a complex polysaccharide onto Q fibrous matrix is feasible. These parameters could be exploited for up‐scaling of polysaccharides for nutraceutical and pharmaceutical applications. © 2013 Society of Chemical Industry

Efficient and versatile fibrous adsorbent based on magnetic amphiphilic composites of chrysotile/carbon nanostructures for the removal of ethynilestradiol

In this work, chrysotile was used as support to grow carbon nanotubes and nanofibers to produce fibrous amphiphilic magnetic nanostructured composites. Iron impregnated on the chrysotile surface at 1, 5 and 15wt% was used as catalyst to grow carbon nanostructures by CVD (chemical vapor deposition) with ethanol at 800°C. Raman, TG/DTA, Mössbauer, XRD, BET, SEM, TEM, elemental analyses and contact angle measurements suggested the formation of a complex amphiphilic material containing up to 21% of nanostructured hydrophobic carbon supported on hydrophilic Mg silicate fibers with magnetic Fe cores protected by carbon coating. Adsorption tests for the hormone ethynilestradiol (EE), a hazardous water contaminant, showed remarkable adsorption capacities even compared to high surface area activated carbon and multiwall carbon nanotubes. These results are discussed in terms of the hydrophobic surface of the carbon nanotubes and nanofibers completely exposed and accessible for the adsorption of the EE molecules combined with the hydrophilic Mg silicate surface which allows good dispersion in water. The composites are magnetic and after adsorption the dispersed particles can be removed by a simple magnetic process. Moreover, the fibrous composites can be conformed as threads, screens and pellets to produce different filtering media.