Investigation on selective adsorption of Hg(II) ions using 4‐vinyl pyridine grafted poly(ethylene terephthalate) fiber

In the work, poly(ethylene terephthalate) (PET) fibers were grafted with 4‐vinyl pyridine (4‐VP) monomer using benzoyl peroxide (Bz₂O₂) as initiator in aqueous media. The removal of Hg(II) ions from aqueous solution by the reactive fiber was examined by batch equilibration technique. Effects of various parameters such as pH, graft yield, adsorption time, initial ion concentration, and adsorption temperature on the adsorption amount of metal ions onto reactive fibers were investigated. The optimum pH of Hg(II) was found 3. The maximum adsorption capacity was found as 137.18 mg g^?1. Moreover such parameters as the adsorption kinetics, the adsorption isotherm, desorption time and the selectivity of the reactive fiber were studied. The adsorption kinetics is in better agreement with pseudo‐first order kinetics, and the adsorption data are good fit with Freundlich isotherms. The grafted fiber is more selective for Hg(II) ions in the mixed solution of Hg(II)‐Ni(II), Hg(II)‐Zn(II), and Hg(II)‐Ni(II)‐Zn(II) at pH 3. Adsorbed Hg(II) ions were easily desorbed by treating with 1M HNO₃ at room temperature. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Adsorption behavior of copper(II) ion from aqueous solution on methacrylic acid‐grafted poly(ethylene terephthalate) fibers

The adsorption behavior of methacrylic acid‐grafted poly(ethylene terephthalate) fibers was studied toward the copper(II) ion in aqueous solutions by a batch equilibriation technique. The influence of treatment time, temperature, pH of the solution, metal ion concentration, and graft yield were considered. One hour of adsorption time was found sufficient to reach adsorption equilibrium for the copper(II) ion. It was found that the adsorption isotherm of Cu(II) fits Langmuir‐type isotherms. The adsorption process is not affected by the temperature when treated with low ion concentration, but is remarkably decreased at a high ion concentration. The heat of adsorption value was calculated as 0.71 kcal/mol. It was found that the reactive fibers are stable and regenerable by acid without losing their activity. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 766–772, 2000     

Adsorption of hexavalent chromium from aqueous solutions using 4-vinyl pyridine grafted poly(ethylene terephthalate) fibers

Summary Sorption of hexavalent chromium ions from aqueous solution by 4- vinyl pyridine (4-VP) grafted poly(ethylene terephthalate) (PET) fibers was studied. The Influences of adsorption time, pH of solution and Cr(VI) concentration on the adsorbed amount were investigated. 30 minutes of treatment time was found to be sufficient to reach equilibrium. pH 3.0 was found as the optimum pH value in the process. The maximum adsorption capacity of the material (k_s) was found to be 263.16 mg g^-1. It was found that the reactive fibers are stable and regenerable by acid or base without losing their activity.     

Preparation of amidoximated polyester fiber and competitive adsorption of some heavy metal ions from aqueous solution onto this fiber

In this study, a fibrous adsorbent containing amidoxime groups was prepared by graft copolymerization of acrylonitrile (AN) onto poly(ethylene terephthalate) (PET) fibers using benzoyl peroxide (Bz₂O₂) as initiator in aqueous solution, and subsequent chemical modification of cyano groups by reaction with hydroxylamine hydrochloride in methanol. The grafted and modified fibers were characterized by FTIR, TGA, SEM, and XRD analysis. The crystallinity increased, but thermal stability decreased with grafting and amidoximation. The removal of Cu(II), Ni(II), Co(II), Pb(II), and Cd(II) ions from aqueous solution onto chelating fibers were studied using batch adsorption method. These properties were investigated under competitive conditions. The effects of the pH, contact time, and initial ion concentration on the removal percentage of ions were studied. The results show that the adsorption rate of metal ions followed the given order Co(II) > Pb(II) > Cd(II) > Ni(II) > Cu(II). The percentage removal of ions increased with initial ion concentration, shaking time, and pH of the medium. Total metal ion removal capacity was 49.75 mg/g fiber on amidoximated fiber. It was observed that amidoximated fibers can be regenerated by acid without losing their activity, and it is more selective for Pb(II) ions in the mixed solution of Pb‐Cu‐Ni–Co‐Cd at pH 4. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Adsorption of copper(II), cobalt(II), and iron(III) ions from aqueous solutions on poly(ethylene terephthalate) fibers

The adsorption behavior of poly(ethylene terephthalate) (PET) fibers towards copper(II), cobalt(II), and iron(III) ions in aqueous solutions was studied by a batch equilibriation technique. Influence of treatment time, temperature, pH of the solution, and metal ion concentration on the adsorption were investigated. Adsorption values for metal ion intake followed the following order: Co(II) > Cu(II) > Fe(III). One hour of adsorption time was found sufficient to reach adsorption equilibrium for all the ions. The rate of adsorption was found to decrease with the increase in the temperature. Langmuir adsorption isoterm curves were found to be significant for all the ions studied. The heat of adsorption values were calculated as −5, −2.8, and −3.6 kcal/mol for Cu(II), Co(II), and Fe(III) ions, respectively. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1935–1939, 1998     

Adsorption properties of poly(acrylaminophosphonic-carboxyl-hydrazide)type chelating fiber for heavy metal ions

In this article, the adsorption properties of poly(acrylaminophosphonic-carboxyl-hydrazide) chelating fibers for Cu(II), Cd(II), Co(II), Mn(II), Pb(II), Zn(II), Ni(II), and Cr(III) are investigated by a batch technique. Based on the research results of binding capacity, adsorption isotherm, effect of pH value on sorption, and adsorption kinetics experiments, it is shown that the poly(acrylaminophosphonic-carboxyl-hydrazide) chelating fibers have higher binding capacities and good adsorption kinetic properties for heavy metal ions. The sorption of the metal ions on the chelating fibers is strongly dependent on the equilibrium pH value of the solution. The adsorption isotherms of Cu(II) and Cd(II) on the chelating fiber exhibit a Langmuir-type equation. The adsorbed Cu(II), Cd(II), Zn(II), and Pb(II) could be eluted by diluted nitric acid. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 7–14, 1998     

Modification and characterization of poly (ethylene terephthalate)‐grafted‐acrylic acid/acryl amide fiber for removal of lead from human plasma and environmental samples

A new fibrous adsorbent was prepared by grafting acrylic acid/acryl amide (AA/AAm) comonomers onto poly (ethylene terephthalate) (PET) fibers. The resulting sorbent has been characterized by Fourier transform infrared (FT‐IR), elemental analysis, thermogravimetric analysis (TGA), FT‐Raman, and scanning electron microscopy (SEM) and studied for the preconcentration and determination of trace Pb (II) ion from human biological fluid and environmental water samples. The optimum pH value for sorption of the metal ion was 8. The sorption capacity of functionalized resin is 44.1 mg g^?1. The chelating sorbent can be reused for 20 cycles of sorption–desorption without any significant change in sorption capacity. A recovery of 100.2% was obtained for the metal ion with 0.5M nitric acid as eluting agent. Effect of grafting yield, shaking time, shape of sorbent, and pH of the medium on adsorption of the metal ion were investigated. Scatchard analysis revealed that the homogeneous binding sites were formed in the polymers. The equilibrium adsorption data of Pb (II) on modified fiber were analyzed by Langmuir, Freundlich, Temkin, and Redlich‐Peterson models. Based on equilibrium adsorption data, the Langmuir, Freundlich, and Temkin constants were determined as 0.236, 10.544, and 9.497 at pH 8 and 20°C, respectively. The method was applied for lead ions determination from human plasma and sea water sample. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Lead(II) Adsorption from Aqueous Solution by Poly(ethylene terephthalate)-g-Acrylamide Fibers

In this study, a reactive fibrous adsorbent was prepared by graft copolymerization of Acrylamide (AAm) onto poly(ethylene terephthalate) (PET) fibers and the adsorption properties of Pb(II) ion from aqueous solution by the reactive fibers were examined by batch equilibration technique. The effects of graft yield, pH, adsorption time, initial ion concentration and adsorption temperature on the adsorption amount of Pb(II) ion was studied. The results show that the adsorption amounts of Pb(II) ion increased with grafting yield, shaking time, initial ion concentration and adsorption temperature. Adsorption of Pb(II) ion was strongly affected by pH. A Lagergren pseudo-second-order was the model that best described the adsorption mechanism. It was found that the adsorption isotherm of the Pb(II) ion fit Langmuir-type isotherms. From the Langmuir equation the adsorption capacity was found as 39.57 mg/g fiber for Pb(II) ion for the copolymer with a graft yield of 15.7%. Quantitative desorption of Pb(II) from reactive fibers were found to be 96% by 5 M HNO₃. Five adsorption–desorption cycles demonstrated that the reactive fibers were suitable for repeated use without considerable change in adsorption capacity. The results of the thermodynamic study indicated that the adsorption processes was endothermic and spontaneous.     

Polyelectrolyte-Cu(II) interactions studied by cyclic voltammetry

SUMMARY The polymer-metal ion interactions were studied by cyclic voltammetry. These were carried out with poly(acrylic acid)-Cu(II) and poly(vinylsulfonic acid)-Cu(II) systems at different pH. At low pH, the polymer was adsorbed on the electrode surface increasing the irreversibility of the Cu²⁺/Cu(s) redox system. At pH 2.7, it was possible to demonstrate that the interaction between Cu(II) and poly(vinylsulfonic acid) is basically electrostatic and with poly(acrylic acid) a complex formation also exists. Received: 5 April 2000/Accepted: 16 August 2000     

Photoinitiated surface grafting of synthetic fibers,III. Photoinitiated surface grafting of poly(ethylene terephthalate) fibers

Photoinitiated surface grafting of acrylic acid (AA), acrylamide (AM) and 4-vinyl pyridine (VP) onto poly(ethylene terephthalate) (PET) fibers (a commercial textile yarn) has been studied using benzophenone (BP) as photoinitiator. A continuous process as previously described has been applied, which involves presoaking of the PET yarn in a solution of initiator and monomer in acetone and UV irradiation in nitrogen atmosphere. The resulting grafted polymer on the fiber surface has been analyzed by ESCA, titration of carboxy groups (grafted AA), and dye absorption. The relative ESCA intensities (RI) of O1s/C1s and N1s/C1s are used as measure for grafted AA, AM and VP, respectively, after recording the RI-values for ungrafted fibers. For grafting with AA, the RI-values increased from 32.8% (background) to 48.6% after 20 s irradiation time. The amount of carboxy groups measured by titration increased from 0.045 to 0.106 mmol/m². Assuming an even coverage of grafted AA polymer, this means a grafted layer of 4.8 nm thickness. After grafting, the adsorption of the dye Crystal Violet (CV) from aqueous solution increased by about 3 times. With AM as monomer, the RI-values increased from 2.6 (background) to 14.8% and the adsorption of a direct dye Sirius Lichtbordo B-LL increased by about 6 times. With VP as grafted monomer, the RI-values increased from about 2.6 (background) to 5.1% and the adsorption of the direct dye increased by about 4 times.     

Adsorption of metal cations from aqueous solutions onto the pH responsive poly(vinylidene fluoride grafted poly(acrylic acid) (PVDF-PAA) membrane

This study investigated the influence of pH of adsorption medium and co-adsorptive metal cations for the adsorption of potassium (K⁺) and magnesium (Mg²⁺) ions onto poly (vinylidene fluoride) grafted poly(acrylic acid) (PAA-PVDF) membrane. At pH 4.8, the adsorption of potassium and magnesium was minimal, because of nearly non-dissociated carboxylic acid groups of PAA-chains, but adsorption increased with increasing ion concentration. The interaction of the studied cations between PVDF-PAA membranes increased considerably at pH 7.0 the dissociation of carboxylic acid groups of PAA. The addition of ionic substances (calcium (Ca²⁺) and sodium (Na⁺) to the adsorption medium reduced the adsorption of potassium and magnesium onto the membrane, because of co-adsorption. Divalent calcium reduced more effectively than univalent sodium the adsorption of potassium and magnesium onto the membrane. In conclusion, co-adsorbing ions reduced the adsorbed amount of potassium and magnesium ions due to binding competition. The percentual adsorbed values suggest that adsorption affinity of studied ions onto the PVDF-PAA membrane followed the order Na⁺ < K⁺ < Mg²⁺ < Ca²⁺. The effect of metal cations on drug adsorption from biological fluids needs research in the future, because e.g. PVDF-PAA membrane has been used in drug separation processes.     

Surface grafting of polyester fiber with chitosan and the antibacterial activity of pathogenic bacteria

Three polyesters—poly(ethylene terephthalate), poly(2‐methyl‐1,3‐propylene terephthalate‐co‐ethylene terephthalate), and poly(1,4‐cyclohexylene terephthalate‐co‐ethylene terephthalate)—were preirradiated with ⁶⁰Co‐γ‐rays. Then, acrylic acid and N‐vinylformamide were grafted to these irradiated fibers. Fibers grafted with N‐vinylformamide were further hydrolyzed with acid so that the amide groups would convert into amino groups, and they were treated with glutaraldehyde so that aldehyde groups would be introduced. Chitosan or chitooligosaccharide was then grafted to these fibers via either esterification or imine formation. Four pathogenic bacteria—methicillin‐resistant Staphylococcus aureus‐1 (MRSA), Staphylococcus aureus‐2, Escherichid coli, and Pseudomonas aeruginosa—were tested to determine the antibacterial activities of chitosan‐grafted and chitooligosaccharide‐grafted fibers. The results showed that grafting chitosan via imine formation could achieve a higher surface density for amino groups and give higher antibacterial activity to those four bacteria tested. The antibacterial activity for E. coli was the highest and that for MRSA was the lowest among the four bacteria tested. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 2977–2983, 2002     

Adsorption behavior of Congo red from an aqueous solution on 4‐vinyl pyridine grafted poly(ethylene terephthalate) fibers

In this study, a reactive fibrous adsorbent was prepared through the grafting of 4‐vinyl pyridine monomer onto poly(ethylene terephthalate) (PET) fibers for the removal of Congo red (CR) dye from an aqueous solution with the batch adsorption method. Effects of various parameters such as the grafting yield, pH, treatment time, and initial dye concentration on the amount of adsorption of the dye onto the reactive fibers were investigated. The effective pH was 4.0 for adsorption on grafted PET fibers. The sufficient time to attain equilibrium was 150 min. The maximum adsorption capacity of the reactive fibers for CR was 17.3 mg/g of fiber. The rates of adsorption conformed to pseudo‐second‐order kinetics with good correlation. The adsorption isotherm of CR fit a Langmuir‐type isotherm. The reactive fibers were stable and regenerable by acid and base without loss of activity. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Synthesis and application of cotton‐based chelate fibers grafted with poly(1‐vinyl‐1,2,4‐triazole) side chains

Cotton‐based chelate fibers grafted with poly(1‐vinyl‐1,2,4‐triazole) (PVTAZ) side chains were synthesized facilely by ozone‐induced graft polymerization of 1‐vinyl‐1,2,4‐triazole (VTAZ) monomer onto cotton fibers. The synthesis conditions were optimized to improve the yield and mechanical strength of the products. The obtained cotton‐g‐PVTAZ fibers were characterized and evaluated for batch adsorption of heavy metal ions from aqueous solutions. The maximum adsorption capacity of Ag(I), Pb(II), and Cu(II) on the fibers at pH 6.8 was 522, 330, and 184 mg/g, respectively. At 30% graft yield, the Young's modulus of cotton fiber increased about 26.5%, and its adsorption capacities of Ag(I), Pb(II), and Cu(II) increased about 2.6, 1.9, and 1.4 times, respectively. After washed with 0.1 mol/L HNO₃ solutions, the adsorbed metal ions were eluted, and the regenerated cotton‐g‐PVTAZ fibers could be used repeatedly for water treatment. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41617.     

Preparation and application of glycidyl methacrylate and methacrylic acid monomer mixture‐grafted poly(ethylene terephthalate) fibers for removal of methylene blue from aqueous solution

A novel fibrous adsorbent that grafts glycidyl methacrylate (GMA) and methacrylic acid (MAA) monomer mixture onto poly(ethylene terephthalate) (PET) fibers was used for removal of methylene blue (MB) in aqueous solutions by a batch equilibration technique. The operation parameters investigated included, pH of solution, removal time, graft yield, dye concentration, and reaction temperature. The adsorption rate of MB is much higher on the MAA/GMA‐grafted PET fibers than on the ungrafted PET fibers. MB was removed 99% the initial dye concentration at 10 mg L⁻¹ and 93% at 200 mg L⁻¹ by monomers mixture‐grafted PET fibers. Pseudofirst order and pseudosecond order kinetic equations were used to examine the experimental data of different graft yield. It was found that the pseudosecond order kinetic equation described the data of dye adsorption on fibrous adsorbent very well. The experimental isotherms data were analyzed using Langmuir and Freundlich isotherm models. The data was that Freundlich isotherm model fits the data very well for the dyes on the fibers adsorbent. The dye adsorbed was easily desorbed by treating with acetic acid/methanol mixture (50% V/V) at room temperature. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

New modified poly (ethylene terephthalate) (MPET)-based adsorbent for heavy metal ions

Modified poly(ethylene terephthalate) (MPET) samples of both powder and fiber types, which contain sodium 5-sulfodimethyl isophthalate as the third comonomer component, were explored as an adsorbent for the elimination of heavy metal ions, e.g., Cr³⁺, Pb²⁺, and Cd²⁺, in wastewater. The ions were preferentially adsorbed on finer particles at a lower temperature and pH 4 and were exothermically chemisorbed onto the MPETs via an ionic interaction. It was also found that among the ions Cr³⁺ is the most preferentially adsorbed, followed by Pb²⁺ and Cd²⁺ ions and the adsorption capability of MPETs increased considerably with the presence of phenol. The separation factor indicated that the MPET fiber wastes may possibly be reutilized as an economical adsorbent for heavy metal ions in wastewater.     

Grafting of the acrylic acid on poly(ethylene terephthalate)

A study has been made of the effect of solvent nature, concentrations of monomer, initiator and homopolymerization inhibitors, and initial polymer structure on the modification of poly(ethylene terephthalate) (PET) films and fibers by grafting the acrylic acid (AA). AA grafting initiated by radicals formed from thermal decomposition of benzoyl peroxide. It has been established that preswelling of PET in dichloroethane leads to changes in its sorption–diffusion properties and favors an increase in the degree of grafting. Addition of the Fe(II), Ni(II), and Cu(II) salts to AA solution decreased homopolymer yield. The studied process of grafting can be described by equations of diffusion kinetics. Distribution of the poly(acrylic acid) (PAA) over the cross section of samples and a number of physical and chemical properties depend also on conditions of performing the graft polymerization.     

Complexation of samarium ion with poly(acrylic acid) grafted onto polyethylene by radiation-induced method

Acrylic acid was graft-polymerized onto polyethylene powder by preirradiation method. The grafted powder (PE-g-AA) rapidaly adsorbed Sm^3? ion in high efficiency. The poly(acrylic acid) grafted to the surface region of PE acted as an effective chelating site for the relatively large Sm ion. The complex formation constant of Sm ion with PE-g-AA was much larger than those of Sm ion with poly(acrylic acid) and propionic acid and of Cu²⁺ ion with PE-g-AA.     

Photoinitiated surface grafting of synthetic fibers,IV. Applications of textile dyes onto surface-photografted synthetic fibers

High-strength polyethylene (HSPE), polypropylene (PP), poly(ethylene terephthalate) (PET), and poly(vinyl alcohol) (PVA) textile yarns have been surface-photografted with various functional monomers, such as acrylic acid (AA), acrylamide (AM), glycidyl acrylate (GA) and 4-vinyl pyridine (VP), by means of the continuous presoaking process developed. The dyeing of these surface-modified yarns with various textile dyes has been investigated. In general, considerable improvements of dyeability have been observed. The dye adsorption of the surface-photografted fibers is influenced by many factors, such as type of fiber, amount and properties of the functional monomer grafted on the surface of the fibers, type of textile dye, etc. The fibers surface-grafted with a monomer containing basic groups, such as acrylamide and 4-vinyl pyridine, are efficiently dyed with an acid dye. Conversely, a fiber surface-grafted with acidic functional monomer is easily dyed to deep shades with basic dyes. The dye adsorption increases monotonically with increasing grafting measured in ESCA spectra as relative intensities of relevant lines. The ungrafted HSPE, PP and PET fibers can be dyed to some extent with certain dyes. In the present work, the dye adsorption increased by 3.4 times for HSPE fiber grafted with GA and dyed with the metal complex dye IO, by 7.9 times for PP fiber grafted with AA and dyed with the basic dye MB, by 6.1 times for PET with AM and with the direct dye SL, and by about 15.3 times for PVA with VP and with the acid dye TE.     

Lipases improve the grafting of poly(ethylene terephthalate) fabrics with acrylic acid

In this study, poly(ethylene terephthalate) (PET) fabrics were modified with two types of commercial lipases, namely, Lipex and Lipolase, and grafted with acrylic acid (AA) to improve their absorption properties. The effects of the enzyme concentration, reaction temperature, time, and pH on the grafting of AA onto PET were investigated. The pretreatment of PET with lipases increased the amount of AA that was introduced to the PET fibers, whereas AA grafting onto the untreated PET fabrics led to lower graft yields. Fourier transform infrared spectroscopy and scanning electron microscopy were used to characterize the AA‐grafted pretreated polyester fabrics. A new band appearing at 1546 cm^?1 in the Fourier transform infrared spectrum implied that AA was introduced onto the PET fabrics. The surfaces of the fabric fibers presented in scanning electron microscopy micrographs clearly indicated the formation of a layer of grafted poly (acrylic acid). The results show that the density of surface grafting was improved by the lipase pretreatment. The increase in grafting was higher for Lipex than for Lipolase. The highest graft yield was obtained with 1% Lipex and Lipolase for 30 min at pH values of 7 and 5, respectively. There were no significant changes in the tenacity or weight reduction of the fabrics. The moisture content of the samples increased linearly with increasing graft yield. This was higher for the pretreated fabrics grafted with Lipex. A higher color strength was obtained for grafted PET samples that were pretreated with Lipex when they were dyed in alkaline aqueous solutions. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010