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1.
Waste poly(p‐phenylene terephthalamide) fibers (PPTA) were chemically modified through nitration and nitro‐reduction reactions to obtain nitro‐ and amino‐containing fibers and used as adsorbents for metal ions. The structures of the modified fibers were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X‐ray diffraction (XRD), and thermogravimetric (TG) analysis. Metal ions, such as Ni2+, Pb2+, Cu2+, and Hg2+, were used to determine the adsorption capacities of the PPTA fibers before and after modification in aqueous solutions. The results showed that the modification improved the adsorption capability of fibers and extraction ratio of metal ions significantly. The adsorption mechanism of modified PPTA fibers for metal ions was proposed. The adsorption processes of Ni2+, Pb2+, and Cu2+ followed well a pseudosecond‐order model onto PPTA‐NH2. The Langmuir and Freundlich models were employed to fit the isothermal adsorption. The results revealed that the linear Langmuir isotherm model is better‐fit model to predict the experimental data. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

2.
Kapok fiber, a natural hollow fiber with thin shell and large cavity, has rarely been used as adsorbent for heavy metal ions. In this paper, kapok fibers were modified with diethylenetriamine pentaacetic acid (DTPA) after hydrophilicity treatment. The adsorption behavior of the resultant kapok-DTPA influenced by pH, adsorption time and initial concentration of metal ion was investigated. The results demonstrate that adsorption equilibrium was reached within 2 min for Pb2+ and Cd2+. Adsorption kinetics showed that the adsorption rate was well fitted by pseudo-second-order rate model. The adsorption isotherms were studied, and the best fit was obtained in the Langmuir model. The maximum adsorption capacities of kapok-DTPA were 310.6 mg g?1 for Pb2+, 163.7 mg g?1 for Cd2+, 101.0 mg g?1 for Cu2+, respectively. After eight desorption and re-adsorption loops, the lost adsorption capacities for Pb2+ and Cu2+ were less than 10 %. Because of the large specific area derived from the hollow fiber structure, kapok-DTPA exhibited much better adsorption capacity compared with many other reported adsorbents based on natural materials.  相似文献   

3.
In this study, poly(amic acid)-modified biomass was prepared to improve the adsorption capacities for two cationic dyes, methylene blue and basic magenta. X-ray photoelectron spectroscopy and potentiometric titration demonstrated that a large number of imide, amine, and carboxyl groups were introduced on the biomass surface, and the concentrations of these functional groups were calculated to be 0.27, 1.08, and 1.08 mmol g?1 by using the first derivative method. According to the Langmuir equation, the maximum uptake capacities (q m) for methylene blue and basic magenta were 680.3 and 353.4 mg g?1, respectively, which were 13- and sevenfold than that obtained on the unmodified biomass. Adsorption kinetics study showed that the completion of the adsorption process needed only 40 min, which is faster than the common sorbent such as activated carbon and resin. Experimental results showed that pH and ionic strength had little effect on the capacity of the modified biomass, indicating that the modified biomass had good potential for practical use.  相似文献   

4.
Macrocyclic pyridone pentamer‐functionalized nanofiber was fabricated through electrospinning for selective heavy metal cation removal from aqueous solution. Parameters influencing the adsorption process, including contact time, initial metal cation concentration, and solution pH, were evaluated, and the optimized adsorption condition was figured out accordingly. The adsorption study demonstrated that the process followed the pseudosecond‐order kinetic models and Langmuir isothermal model. The selectivity of the nanofiber toward metal cations was studied, and it was found that it showed a high adsorption affinity toward Pb2+ over other metal cations such as Cu2+, Ca2+, Co2+, Zn2+, and Ni2+. The nanofiber could be easily regenerated by deadsorption with ethylenediaminetetraacetic acid solution. The above results indicate the potential application of the nanofiber in the metal cation separation field.  相似文献   

5.
A graft copolymerization was performed using free radical initiating process to prepare the poly(methyl acrylate) grafted copolymer from the tapioca cellulose. The desired material is poly(hydroxamic acid) ligand, which is synthesized from poly(methyl acrylate) grafted cellulose using hydroximation reaction. The tapioca cellulose, grafted cellulose and poly(hydroxamic acid) ligand were characterized by Infrared Spectroscopy and Field Emission Scanning Electron Microscope. The adsorption capacity with copper was found to be good, 210 mg g?1 with a faster adsorption rate (t1/2 = 10.5 min). The adsorption capacities for other heavy metal ions were also found to be strong such as Fe3+, Cr3+, Co3+ and Ni2+ were 191, 182, 202 and 173 mg g?1, respectively at pH 6. To predict the adsorption behavior, the heavy metal ions sorption onto ligand were well-fitted with the Langmuir isotherm model (R2 > 0.99), which suggest that the cellulose-based adsorbent i.e., poly(hydroxamic acid) ligand surface is homogenous and monolayer. The reusability was checked by the sorption/desorption process for six cycles and the sorption and extraction efficiency in each cycle was determined. This new adsorbent can be reused in many cycles without any significant loss in its original removal performances.  相似文献   

6.
Biosorption of Cu2+ and Pb2+ by Cladop- hora fascicularis was investigated as a function of initial pH, initial heavy metal concentrations, temperature and other co-existing ions. Adsorption equilibriums were well described by Langmuir and Freundlich isotherm models. The maximum adsorption capacities were 1.61 mmol/g for Cu2+ and 0.96 mmol/g for Pb2+ at 298 K and pH 5.0. The adsorption processes were endothermic and biosorption heats calculated by the Langmuir constant b were 39.0 and 29.6 kJ/mol for Cu2+ and Pb2+, respectively. The biosorption kinetics followed the pseudo-second order model. No significant effect on the uptake of Cu2+ and Pb2+ by co-existing cations and anions was observed, except EDTA. Desorption experiments indicated that Na2EDTA was an efficient desorbent for the recovery of Cu2+ and Pb2+ from biomass. The results showed that Cladophora fascicularis was an effective and economical biosorbent material for the removal and recovery of heavy metal ions from wastewater.  相似文献   

7.
Poly(hydroxamic acid) ligand was synthesized using ester functionalities of cellulose‐graft‐poly(methyl acrylate) copolymer, and products are characterized by Fourier transform infrared spectroscopy, field emission scanning electron microscopy, high‐resolution transmission electron microscopy, and X‐ray photoelectron spectroscopy analysis. The poly(hydroxamic acid) ligand was utilized for the sensing and removal of transition metal ions form aqueous solutions. The solution pH is found a key factor for the optical detection of metal ions, and the reflectance spectra of the [Cu‐ligand]n+ complex were observed to be the highest absorbance 99.5% at pH 6. With the increase of Cu2+ ion concentration, the reflectance spectra were increased, and a broad peak at 705 nm indicated that the charge transfer (π‐π transition) complex was formed. The adsorption capacity with copper was found to be superior, 320 mg g?1, and adsorption capacities for other transition metal ions were also found to be good such as Fe3+, Mn2+, Co3+, Cr3+, Ni2+, and Zn2+ were 255, 260, 300, 280, 233, and 223 mg g?1, respectively, at pH 6. The experimental data show that all metal ions fitted well with the pseudo‐second‐order rate equation. The sorption results of the transition metal ions onto ligand were well fitted with Langmuir isotherm model (R2 > 0.98), which implies the homogenous and monolayer character of poly(hydroxamic acid) ligand surface. Eleven cycles sorption/desorption process were applied to verify the reusability of this adsorbent. The investigation of sorption and extraction efficiency in each cycle indicated that this new type of adsorbent can be recycled in many cycles with no significant loss in its original detection and removal capability. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

8.
A calix‐conjugated thermo‐responsive hydrogel containing 15% tetra(5‐hexenyloxy)‐p‐tert‐butylcalix[4]arene (HBCalix), P(NIPAM‐co‐HBCalix), was used to remove nickel(II) ions from water. Both thermo‐sensitive properties and the Ni2+‐adsorption capabilities of the prepared P(NIPAM‐co‐HBCalix) hydrogels are investigated. Introduction of the monomer HBCalix considerably enhanced the adsorption of Ni2+ onto the hydrogel by chelation between hexenyloxy groups and metal ion. When HBCalix units capture Ni2+ and forms HBCalix/Ni2+ host–guest complexes, the lower critical solution temperature of the hydrogel shifts to a higher temperature due to both the repulsion between charged HBCali/Ni2+ groups and the osmotic pressure within the hydrogel. Adsorption studies were carried out by varying contact time, counter ion and initial concentration of Ni2+. The evaluation of adsorption properties showed that the hydrogel exhibited better correlation with Langmuir isotherm model. P(NIPAM‐co‐HBCalix) could be used repeatedly with little loss in adsorption capacity by simply changing the environmental temperature. This kind of ion‐recognition hydrogel is promising as a novel adsorption material for adsorption and separation of Ni2+ ions. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2401–2408  相似文献   

9.
A highly specific lead-binding peptide ThrAsnThrLeuSerAsnAsn was displayed on Escherichia coli, and lead adsorption characteristics of the recombinant bacteria were investigated. Cell surface-displayed peptide was expressed under the control of an arabinose promoter using outer membrane protein C (OmpCt) as an anchoring motif. The optimal induction period and arabinose concentration for the expression of peptide-fused OmpCt were determined to be 2 h and 0.001 g/L, respectively. Selective adsorption of Pb2+ onto recombinant cells was verified with individual or combinatory use of four metal ions, Pb2+, Ni2+, Co2+, and Cu2+; the amount of bound Pb2+ onto the biosorbents was significantly higher than the other metal ions. The adsorption isotherm of recombinant cells for Pb2+ followed the Langmuir isotherm with a maximum adsorption loading (q max) of 526 μmol/g dry cell weight.  相似文献   

10.
Chemical modification of chitosan has become increasingly essential due to chitosan versatility that enables the material to be easily modified in a way of increasing its properties in adsorption processes. In this investigation, chitosan solution was cross‐linked with glutaraldehyde the cross‐linked solution was used in producing the beads and thereafter grafted with ethylene acrylic acid. The chemical functionalities of the beads were obtained by Fourier transform infrared spectroscopy (FTIR), Scanning electron microscope (SEM), X‐ray diffraction (XRD) and Thermogravimetric analysis (TGA). Adsorption of Pb2+, Cu2+, Ni2+, Zn2+, Cr6+ and Cd2+ ions from single component aqueous mixture by grafted cross‐linked chitosan beads (GXXB) was studied as a function of pH, temperature, initial concentration, contact time, agitation speed and ionic strength. Equilibrium data was obtained from the adsorption experiment, the data were applied in isotherm, thermodynamics and kinetic studies. The Langmuir, Temkin and Dubinin‐kaganer‐Radushkevich (DKR) model were successful in describing the isotherm data for the considered metal ions while the Freundlich model was not efficient in describing the experimental data. Pseudo‐second order and intra‐particle model described the kinetic data quite well. Thermodynamic parameters such as Gibb's free energy change (?Go), enthalpy change (?Ho) and entropy change (?So) were calculated and the results showed the adsorption of Pb2+, Cu2+, Ni2+, Zn2+, Cr6+ and Cd2+ ions onto GXXB is spontaneous and endothermic in nature. Regeneration of the used adsorbent was effective for the studied metal ions.  相似文献   

11.
《Arabian Journal of Chemistry》2020,13(11):7695-7706
A batch adsorption experiments were carried out to study the role of nanoparticles and nanocomposite on removal of some heavy metals and fungicides from aqueous solution. Nano-Hydroxyapatite (n-HAP), Nano-Bentonite (n-Bo) and Bentonite-hydroxyapatite nanocomposite (B-HAP NC) evaluated for the removal of some heavy metals and fungicides. The nanoparticles and nanocomposite were characterized by TEM, SEM and AFM, X-ray powder diffraction (XRD) and BET surface area. The batch adsorption was done using nanoparticles with Pb2+ and Ni2+ as example of heavy metals with concentrations up to 25 mgL−1. Also, the adsorption experiment was conducted using nano-particles (n-HAP, n-Bo and B-HAP NC) with fungicides Stop Feng and Eurozole with concentrations 20 to 200 μg L−1. Langmuir and Freundlich isotherm equations were employed to study the adsorption. The adsorption kinetics were conducted metal ion (Pb2+ and Ni2+) with residence time. The results indicated the maximum adsorption capacity of Ni+2 was occurred on (n-HAP). While that maximum adsorption capacity of Pb2+ was occurred on (B-HAP NC). The rate of Ni+2 removal was found to be very rapid during the initial 60 min. The adsorption of Pb+2 by the n-HAP and (B-HAP NC) was a slow increase with time, it did not bring any remarkable effect. Also, the efficiency of adsorbent compounds used to remove the residue of fungicides Stop Feng and Eurozole shown the highest removal rates obtained with used nano-hydroxyapatite followed by bentonite-hydroxyapatitenanocomposite and nano-bentonite, respectively. The current results are very useful in the treatment of wastewater and the removal of heavy metals and fungicides, consequently making them suitable for agricultural purposes.  相似文献   

12.
王杰 《高分子科学》2014,32(4):432-438
Nano-sized spherical polymer brushes(SPBs) consisting of both a polystyrene(PS) core and a brush shell of poly(acrylic acid)(PAA), poly(N-acrylcysteamine)(PSH), or poly(N-acrylcysteamine-co-acrylic acid)(P(SH-co-AA)), were prepared by photo-emulsion polymerization. The core-shell structure was observed by dynamic light scattering and transmission electron microscopy. Due to the strengthened Donnan effect, the PAA brush can adsorb heavy metal ions. Effects of the contact time, thickness of PAA brush and pH value on the adsorption results were investigated. Due to the coordination between the mercapto groups and heavy metal ions as well as the electrostatic interactions, SPBs with mercapto groups are capable to remove heavy metal ions selectively from aqueous solutions. The order of adsorption capacity of the heavy metal ions by SPBs with mercapto groups is: Hg2+ ≈ Au3+ Pb2+ Cu2+ Ni2+. The adsorbed heavy metal ions can be eluted from SPB by aqueous HCl solution, and the SPBs can be recovered. After three regenerations the recovered SPBs still maintain their adsorption capacity.  相似文献   

13.
Release of heavy metal onto the water and soil as a result of agricultural and industrial activities may pose a serious threat to the environment. In this study, the adsorption behavior of nano hydroxyapatite with respect to Pb2+, Cd2+ and Ni2+ has been studied in order to consider its application to purity metal finishing wastewater. The batch method has been employed, using metal concentrations in solution ranging from 100 to 400 mg/L. The uptake capacity and distribution coefficients (Kd) were determined for the adsorption system as a function of sorbate concentration. The Langmuir, Freundlich, and Dubinin–Kaganer–Radushkevich (DKR) isotherms applied for sorption studies showed that the amount of metal sorbed on nano hydroxyapatite. It was found that the adsorption phenomena depend on charge density and hydrated ion diameter. According to the equilibrium studies, the selectivity sequence can be given as Pb2+ > Cd2+ > Ni2+. These results show that nano hydroxyapatite holds great potential to remove cationic heavy metal species from industrial wastewater.  相似文献   

14.
The use of iron oxide/amino-functionalized silica core–shell magnetic nanoparticles for preconcentration of Pb2+ followed by its consecutive atomic absorption spectrometry determination is described. Effects of various operating variables, namely, solution pH, initial Pb2+ concentration, contact time, adsorbent dosage, sample volume, concentration and volume of desorbing solution, and co-existing ions on solid-phase extraction (SPE) of Pb2+ were studied by batch equilibrium technique. The experimental adsorption data were well fitted to the Langmuir isotherm model. The Langmuir adsorption capacity and equilibrium time were found to be 100 mg g?1 and 20 min, respectively. The adsorption data were also fitted to kinetic pseudo-first-order and pseudo-second-order models. Kinetic studies showed that the adsorption followed pseudo-second-order model. Under the optimal SPE conditions, the enrichment factor, detection limit and relative standard deviation for determination of Pb2+ were found to be 211, 1 μg L?1, and 3.7 % for 50 μg L?1, respectively. The proposed method was successfully applied to the determination of lead in a real sample with satisfactory results.  相似文献   

15.
In this study, chitosan-g-poly(acrylic acid) (CTS-g-PAA) hydrogel with crosslinked polymeric networks was prepared from an aqueous dispersion polymerization and then used as the adsorbent to recover a valuable metal, Ni2+. The adsorption capacity of CTS-g-PAA for Ni2+ was evaluated and the adsorption kinetics was investigated using Voigt-based model and pseudo-second-order model. In addition, the effects of pH values and coexisting heavy metal ions such as Cu2+ and Pb2+ on the adsorption capacity were studied. The results indicate that the as-prepared adsorbent has faster adsorption rate and higher adsorption capacity for Ni2+ recovery, with the maximum adsorption capacity of 161.80 mg g−1. In a wide pH range of 3–7, the adsorption capacity keeps almost the same, and even under competitive conditions, the adsorption capacity of CTS-g-PAA for Ni2+ is observed to be as high as 54.47 mg g−1. Finally, the adsorption performance of CTS-g-PAA for Ni2+ in real water sample and the reusability of the as-prepared adsorbent were evaluated, and also the controlled adsorption mechanism was proposed.  相似文献   

16.
A novel crosslinked poly(acrylic acid-copolymer-Kryptofix-22-DM) superabsorbent copolymer, poly(AA-co-Kry22-DM), was synthesised by the reaction of 4,13-dimethylacryloyl-1,7,10,16-tetraoxa-4,13-diazacyclooctadecane (Kyrptofix-22-DM) and acrylic acid (AA). Characterisation of the polymers was achieved by FTIR and 1H NMR techniques. Sorption capacity of the crosslinked poly(AA-co-Kry22-DM) superabsorbent copolymer was investigated for Pb2+, Cu2+, Cr3+, Cd2+, Mn2+, Zn2+, and Ni2+ heavy metal ions at different pH values using Freundlich and Langmuir isotherms. Swelling ratio, qv, and distribution ratio, log D, values of the crosslinked poly(AA-co-Kry22-DM) superabsorbent copolymer were calculated at various pH values.  相似文献   

17.
The preparation of malonic acid‐catalyzed carbon xerogels modified with nitric acid and their high performance for adsorption of Cu2+ were investigated. The treated and untreated carbon xerogels (nitrogen‐doped carbon xerogel and carbon xerogel) are mainly microporous with high surface areas (1150.18 and 1201.46 m2 g?1) based on the analysis of N2 adsorption isotherm. Fourier transform infrared spectroscopy study demonstrates that modification process generates a number of functional groups such as carboxyl, carbonyl, and nitrate groups. X‐ray photoelectron spectra analysis shows an increase in the content of O and N after oxidation. The adsorption performance for Cu2+ using different process parameters like initial concentration, contact time, and temperature was investigated. The result indicates that the pseudo‐second order correlates with the experimental data, and the activation energy of Cu2+ adsorption onto nitrogen‐doped carbon xerogel and carbon xerogel is calculated as 15.62 kJ mol?1 and 2.79 kJ mol?1, respectively, indicating the coexistence of chemisorption and ion‐exchange. Langmuir and Freundlich isotherms were used to describe the adsorption behavior of Cu2+. The adsorption of Cu2+ by carbon xerogels modified with nitric acid was fast and had noticeable adsorption capacity, with a higher adsorption capacity than the original carbon xerogels (299.41 vs 260.42 mg g?1). Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

18.
Abstract

Amino-functionalized mesoporous silica nanoparticles (AFMSN) were prepared based on the self-assembly process of the pre-fabricated template of anionic gemini surfactant. The perfect mass ration of the reactants for the synthesis of the AFMSN with high surface area and amino loading was optimized by orthogonal experiments. Adsorption capability of the optimized product for lead ion (Pb2+) was investigated in detail. Specially, the effects of the amino content, solution pH, adsorbent dosage, temperature, and interference of other metal ions on the removal efficiency of Pb2+ were studied. It is found that these factors can greatly affect the removal efficiency of Pb2+ and the prepared adsorbent exhibits the high adsorption selectivity for Pb2+. At an optimal condition, the AFMSN adsorbent presents an excellent adsorption capacity for Pb2+ up to 211.42?mg/g. The adsorption kinetics study revealed that the pseudo-second-order model could well describe the Pb2+ adsorption process, and the adsorption isotherm was fitted well with the Langmuir model. More importantly, the AFMSN adsorbent could be recycled 8 times and a high adsorption efficiency of Pb2+ could still be maintained. Therefore, the prepared AFMSN adsorbent may find practical application in removing Pb2+ from the polluted water.  相似文献   

19.
Molybdenum disulfide (MoS2) has excellent trapping ability for lead ions whereas its micro-/nanoscale size has greatly impeded its practical applications in the flow-through systems. Herein, a millimeter-sized nanocomposite MoS2?001 was synthesized for Pb2+ removal by loading MoS2 nanosheets into a polystyrene cation exchanger D-001 by a facile hydrothermal method. The proposed structure and adsorption mechanism of MoS2?001 was confirmed by the scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) analysis. The nanocomposite showed outstanding adsorption capacity and rapid adsorption kinetic for Pb2+ removal, and the adsorption behavior followed the Langmuir adsorption model and pseudo-first-model kinetic model. Pb2+ uptake by MoS2?001 still maintains a high level even in the presence of extremely highly competitive ions (Ca(II) and Mg(II)), suggesting its high selectivity for Pb2+ adsorption. Besides, the fixed-bed column experiments further certified that MoS2?001 is of great potential for Pb2+ removal from the wastewater in practical engineering applications. Even more gratifying is that the exhausted MoS2?001 can be regenerated by NaCl-EDTANa2 solution without any significant adsorption capacity loss. Consequently, all the results indicated that MoS2?001 is a promising candidate adsorbent for lead-containing wastewater treatment.  相似文献   

20.
A sensitive and simple solid‐phase preconcentration procedure for the determination of trace amount of lead by flame atomic absorption spectrometry (FAAS) is developed. The method is based on the adsorption of Pb2+ on the column of fine grinded eucalyptus stem adsorbent, elution of the column by nitric acid and subsequent determination by FAAS. The effect of different variables such as pH, eluent type, flow rate and interfering ions on the recovery of the analyte was investigated and optimum conditions were established. The adsorption of lead onto fine grinded eucalyptus stem can formally be described by a Langmuir equation with a maximum adsorption capacity of 4.49 mg g?1. A preconcentration factor of 50 was achieved using the optimum conditions. The calibration graph was linear in the range 10–125 ng mL?1 of lead in the initial solution with r = 0.9982. The limit of detection based on 3Sb criterion was 4.5 ng mL?1 and the relative standard deviation for eight replicate measurements of 30 and 80 ng mL?1 of iron was 3.6 and 2.8%, respectively. The method was successfully applied to the determination of lead added to well, tap and wastewater samples.  相似文献   

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