Nanofibrous Adsorbent Research Articles

Cu (II) removal using electrospun dual-responsive polyethersulfone-poly (dimethyl amino) ethyl methacrylate (PES-PDMAEMA) blend nanofibers.

A novel electrospun dual-responsive polyethersulfone-poly(dimethyl amino) ethyl methacrylate nanofibrous adsorbent was fabricated via electrospinning for the removal of Cu (II) from aqueous solution. Morphological, chemical, and dual-responsiveness of the composite nanofibrous adsorbent were characterized using scanning electron microscope equipped with energy dispersive x-ray, Fourier transform infrared, and UV-VIS spectrophotometer, respectively. The obtained uniform and bead-free nanofibers were then used for the removal of Cu (II) from aqueous solution. Results showed that the temperature-responsiveness of the nanofibers is dependent on the pH of the solution, as indicated by the decreasing lower critical solution temperature with increasing pH level. Temperature and pH offer a synergistic effect on the adsorption of Cu (II), with maximum adsorption observed at pH 6.5 at 55 °C. Kinetic, thermodynamic, and isotherm studies indicate that the adsorption of copper ions follows chemisorption and is thermodynamically favored at increasing temperature. From the Langmuir isotherm model, the obtained maximum adsorption capacity, qm, was 161.30 mg g-1 at 55 °C. From the desorption studies, results showed that the maximum desorption was observed at pH 3 at 25 °C. In conclusion, PES-PDMAEMA has the capability to adsorb and desorb Cu (II) by adjusting both pH and temperature, hence it can be considered as an efficient and economical adsorbent for heavy metals such Cu (II).

Removal of lead from aqueous solution with nanofibrous nanocomposite of polycaprolactone adsorbent modified by nanoclay and nanozeolite

Removal of heavy metals from aqueous solutions as hazardous, carcinogenic, and toxic pollutants is considered among the most important environmental issues in recent years. In this study, polycaprolactone nanofibrous adsorbent was prepared by the electrospinning method and then, was modified by clay mineral and zeolite nanoparticles and characterized by field emission scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, and finally, the lead removal ability at an aqueous solution was evaluated. The experiments were carried out intermittently under different process conditions. Then, the impact of effective parameters on lead adsorption process including the initial concentration of the metal solution, pH, the adsorbent amount, and temperature was studied. Also, kinetics, isotherm, and thermodynamics of the adsorption process were determined. The results demonstrated that the addition of clay mineral and zeolite nanoparticles to polycaprolactone have synergistic effect on lead adsorption capacity of nanofibers The results of adsorption processes showed that with increased pH up to 5.5, increased solution concentration up to 25 ppm, decreased adsorbent up to 0.01 g, and increased temperature up to 40 °C, the adsorbent value increased. Second-order pseudo-adsorption kinetics was observed and also lead adsorbent isotherm followed the Freundlich model. The thermodynamic results showed that lead adsorption process with synthetic adsorbent was a spontaneous process.

Synthesis of cellulose acetate/chitosan/SWCNT/Fe3O4/TiO2 composite nanofibers for the removal of Cr(VI), As(V), Methylene blue and Congo red from aqueous solutions

The potential of electrospun cellulose acetate/chitosan/single walled carbon nanotubes/ferrite/titanium dioxide (CA/chitosan/SWCNT/Fe3O4/TiO2) nanofibers was investigated for the removal of Cr(VI), As(V), Methylene blue and Congo red from aqueous solutions via the adsorption and photocatalytic reduction processes. The properties of synthesized SWCNT/Fe3O4/TiO2 and fibers were characterized using TEM, SEM, FTIR, XRD, TGA and BET analysis. In adsorption process, the influence of adsorbent type including SWCNT to Fe3O4 ratio, TiO2 to SWCNT/Fe3O4 ratio and SWCNT/Fe3O4/TiO2 concentration as well as the adsorption parameters including pH, contact time, and initial concentration of adsorbates on the Cr(VI), As(V), Methylene blue and Congo red adsorption in a batch mode was investigated. The reusability of nanofibers was also investigated for five adsorption-desorption cycles. The photocatalytic reduction of Cr(VI), As(V), Methylene blue and Congo red was also investigated using various nanofibrous catalysts. The obtained results indicated that the removal of Cr(VI) and As(V) using CA/chitosan/SWCNT/Fe3O4/TiO2 nanofibrous adsorbent via adsorption process could be preferred for the lower concentrations of metal ions. The photocatalytic reduction was an effective method for the Cr(VI), As(V) removal at higher concentrations and degradation of Methylene blue and Congo red under both lower and higher concentrations of azo dyes.

Fabrication of novel chitosan-g-PNVCL/ZIF-8 composite nanofibers for adsorption of Cr(VI), As(V) and phenol in a single and ternary systems

The chitosan-grafted-poly(N-vinylcaprolactam) (chitosan-g-PNVCL) nanofibers were synthesized via electrospinning method. ZIF-8 metal-organic frameworks nanoparticles were incorporated into the nanofibers for adsorption of Cr(VI), As(V) and phenol from water. The BET, FTIR, XRD and SEM analysis were carrfried out to obtain the characteristics of nanofibers. The optimum parameters of ZIF-8 content, pH, contact time, adsorbent dosage, and initial concentration of adsorbates on the Cr(VI), As(V) and phenol removal were studied. The reusability of synthesized nanofibers for five sorption-desorption cycles was also examined. The maximum experimental adsorption capacity of the chitosan-g-PNVCL/ZIF-8 nanofibers for Cr(VI), As(V) and phenol sorption were 269.2, 258.5 and 152.3 mg g−1, respectively under ZIF-8 concentration of 3 wt.%, adsorbent dosage of 0.5 g/L, pH of 3, equilibrium times of 30 min, and temperature of 25 °C. The kinetic, and isotherm parameters of adsorption process using chitosan-g-PNVCL/ZIF-8 nanofibers were evaluated. In ternary system, the central composite design was applied to investigate the interaction influence of initial concentrations of selected metal ions and phenol on the performance of nanofibrous adsorbent. The obtained results showed the high capability of nanofibers for the removal of heavy metals and organic pollutants from water.

Incorporation of UiO-66-NH2 MOF into the PAN/chitosan nanofibers for adsorption and membrane filtration of Pb(II), Cd(II) and Cr(VI) ions from aqueous solutions.

In the present study, the UiO-66-NH2 MOF synthesized by microwave heating method was incorporated into the PAN/chitosan nanofibers for the removal of Pb(II), Cd(II) and Cr(VI) ions through the adsorption and membrane filtration processes. The synthesized MOFs and nanofibers were characterized using XRD, BET, FTIR, SEM, and DSC analysis. The effect of UiO-66-NH2 MOF content (0-15 wt.%), pH (2-7), contact time(5-90 min), metal ions initial concentration (20-1000 mg/L) and temperature (25-45 °C) was studied on the metal ions adsorption using PAN/chitosan/UiO-66-NH2 nanofibrous adsorbent. The kinetic, isotherm and thermodynamic parameters were evaluated to understand the metal ions adsorption mechanism using nanofibers. The Pseudo-second-order kinetic and Redlich-Peterson isotherm model were well described the experimental sorption data. In the heavy metal ions membrane filtration process, the different parameters such as MOF concentration (2-15 wt.%), membrane thickness (10-70 μm), metal ions concentration (5-50 mg/L), temperature (25-45 °C) and filtration time (1-24 h) were investigated on the performance of PVDF/ PAN/chitosan/UiO-66-NH2 nanofibrous membrane toward metal ions removal. The high water flux and high metal ions removal within 18 h filtration time showed the high potential of PVDF/ PAN/chitosan/UiO-66-NH2 membrane for the removal of metal ions from aqueous solutions.

Removal of boron from aqueous solutions using electrospun PVDF nanofibrous adsorbent modified by poly(glycidyl methacrylate)/glucamine ligands

Removal of boron from aqueous solutions using electrospun PVDF nanofibrous adsorbent modified by poly(glycidyl methacrylate)/glucamine ligands

Breakthrough modelling of glucamine functionalized PVDF nanofibrous adsorbent in a fixed-bed column for separation of boron from water

The performance of new nanofibrous chelating adsorbent, prepared by radiation induced grafting of glycidyl methacrylate onto electrospun poly(vinylidene fluoride) (PVDF) nanofibers followed by functionalization with N-methyl-D-glucamine, for removal of boron from aqueous solutions using a fixed-bed column was evaluated. The breakthrough curve was studied under various parameters including initial concentration, flow rate and bed height at pH 7. The column performance was evaluated with Yoon-Nelson and Thomas adsorption kinetic models. The maximum performance for boron adsorption was obtained at an initial concentration of 10 mg L-1, a space velocity (SV) of 15 h-1 and a room temperature of 28°C. The breakthrough capacity was found to be a function of both initial feed concentration and flow rate. Thomas model was found to best fit the dynamic behaviour of the column. The newly obtained adsorbent was proven to be capable of removing boron efficiently from aqueous solutions in continuous fixed-bed systems at high flow rates and has potential for industrial-scale application. © 2019 Desalination Publications.

Plasma-etched electrospun nanofiber membrane as adsorbent for dye removal

The removal of hazardous dyes from wastewater is essential for environmental remediation. A simple, green and effective air plasma etching treatment was introduced to fabricate PLLA nanofibrous adsorbents. The cationic methylene blue (MB) dye could be rapidly adsorbed on the surface of plasma-etched PLLA nanofiber membrane through electrostatic interaction. It was attributed to the increased surface area and the generated binding sites after the plasma treatment. The adsorption behavior was influenced by both the plasma etching time and the initial MB concentration. It was found that the adsorption kinetics fits well with the pseudo-second order model, and the isotherm data fits well with the Langmuir model, revealing that monolayer MB was chemically adsorbed on the adsorbent. Moreover, the plasma-etched PLLA nanofiber membrane has also exhibited good reusability. It is believed that the plasma treatment may facilitate the design and fabrication of a new class of nanofibrous adsorbents.

Preparation and Adsorption Property of Imido-acetic Acid Type Chelating Nano-fibers by Electro-spinning Technique

A novel nano-fibrous adsorbent from imino-acetic acid (IDA) and polyvinyl alcohol (PVA) mixture solution was prepared by electro-spinning technique. The nano-fibrous adsorbents with imino-acetic acid functional groups were characterized and demonstrated by fourier transform infrared spectrometry (FT-IR) and the scanning electron microscopy (SEM). The effect of the adsorbents to remove heavy metals such as lead (Pb) and copper (Cu) ions from the aqueous solution was studied. The maximum adsorption percentage (SP) of the metal ions can reach 93.08% for Cu (II) and 96.69% for Pb(II), respectively. Furthermore, it shows that the adsorption procedure of the adsorbents is spontaneous and endothermic, and adsorption rate fits well with pseudo-second-order kinetic model. Most importantly, the reusability of the nanofibers for removal of metal ions was also demonstrated to be used at least five times.

Electrospun Nanofibrous Polyacrylonitrile/calixarene Mats: an Excellent Adsorbent for the Removal of Chromate Ions from Aqueous Solutions.

Herein, calixarene molecules containing piperidine units at lower rim or upper rim of calix skeleton was turned into a water resistant composite nanofiber adsorbent using polyacrylonitrile (PAN) polymeric support via electrospinning process. The PAN based calixarene nanofibrous adsorbents showed an excellent adsorption capacity toward the toxic chromate anions in aqueous solution. Furthermore, this new nanofiber mats would be promising filter materials for drinking water purification.

Preparation of amidoxime‐modified polyacrylonitrile nanofibrous adsorbents for the extraction of copper(II) and lead(II) ions and dye from aqueous media

ABSTRACTAmidoxime‐modified polyacrylonitrile nanofibrous films (AOPAN NFs) were prepared via an electrospinning technique. The traditional preparation methods for amidoximated polyacrylonitrile (AOPAN) solution were changed and improved. First, the PAN solution was modified by hydroxylamine hydrochloride to produce an AOPAN solution, and then, a small amount of inhibitor was added to the AOPAN solution for electrospinning. We found that the crosslinking of the AOPAN solution was inhibited by the addition of a small amount of inhibitor; at the same time, the storage time of the AOPAN solution was prolonged. In addition, the prepared AOPAN solution was electrospun into nanofibrous films, which could be used as excellent adsorption materials for Cu(II), Pb(II), and methyl orange (MO) after drying. The maximal adsorption capacities for Cu(II), Pb(II), and MO were 143.47, 178.57, and 68.07 mg/g, respectively. The adsorption capacities of the nanofibrous films were more than 50% that of the first adsorption after four recycling runs; this indicated the reusability of the nanofibrous films for water treatment. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45697.

Electrospun poly(acrylic acid)/poly(vinyl alcohol) nanofibrous adsorbents for Cu(ii) removal from industrial plating wastewater

Nanofibrous adsorbents were fabricated by electrospinning with a blend solution of poly(acrylic acid) (PAA) and poly(vinyl alcohol) (PVA) polymers and used for copper (Cu(ii)) removal from industrial plating wastewater.

Fabrication of PES/NaX nanocomposite nanofibrous adsorbent for the removal of Cu2+, Co2+ and Fe2+ from aqueous solutions

Fabrication of PES/NaX nanocomposite nanofibrous adsorbent for the removal of Cu2+, Co2+ and Fe2+ from aqueous solutions

Selective adsorption of Cr(VI) ions from aqueous solutions using Cr6+-imprinted Pebax/chitosan/GO/APTES nanofibrous adsorbent

In the present study, a novel Cr6+-imprinted Pebax/chitosan/GO/APTES nanofibrous adsorbent (Cr6+-PCGA) was prepared and its performance was compared with PCGA nanofibers for selective sorption of Cr(VI) ions from aqueous solutions. The prepared nanofibers were characterized using FTIR, SEM and EDAX analysis. The influence of batch sorption experiments including GO/APTES content, pH, contact time, Cr(VI) initial concentration and temperature on the Cr(VI) sorption efficiency using synthesized nanofibers was investigated. The Cr(VI) sorption data were well described using pseudo-second-order kinetic and Redlich-Peterson isotherm models. The maximum sorption capacities of Cr6+-PCGA and PCGA nanofibers for Cr(VI) ions sorption were found to be 204.5 and 550.5mgg−1, respectively. Thermodynamic studies indicated an endothermic and spontaneous nature of Cr(VI) ions sorption using both Cr6+-PCGA and PCGA nanofibers. The selectivity coefficient values of Cr(VI)/Pb(II), Cr(VI)/Cu(II) and Cr(VI)/Ni(II) indicated the higher selectivity of Cr6+-PCGA nanofibrous adsorbent for Cr(VI) ions separation compared to PCGA nanofibers. The good stability and reusability of Cr6+-PCGA nanofibrous adsorbent for five sorption/desorption cycles promised a higher potential of ion-imprinted nanofibers for separation of metal ions from aqueous systems in a large scale.

A Novel Nanohybrid Nanofibrous Adsorbent for Water Purification from Dye Pollutants.

In this study, we devised a novel nanofibrous adsorbent made of polyethersulfone (PES) for removal of methylene blue (MB) dye pollutant from water. The polymer shows a low isoelectric point thus at elevated pHs and, being nanofibrous, can offer a huge highly hydroxylated surface area for adsorption of cationic MB molecules. As an extra challenge, to augment the adsorbent’s properties in terms of adsorption capacity in neutral and acidic conditions and thermal stability, vanadium pentoxide (V2O5) nanoparticles were added to the nanofibers. Adsorption data were analyzed according to the Freundlich adsorption model. The thermodynamic parameters verified that only at basic pH is the adsorption spontaneous and in general the process is entropy-driven and endothermic. The kinetics of the adsorption process was evaluated by the pseudo-first- and pseudo-second-order models. The latter model exhibited the highest correlation with data. In sum, the adsorbent showed a promising potential for dye removal from industrial dyeing wastewater systems, especially when envisaging their alkaline and hot conditions.

Removal of nitrate and phosphate using chitosan/Al2O3/Fe3O4 composite nanofibrous adsorbent: Comparison with chitosan/Al2O3/Fe3O4 beads

In the present study the chitosan/Al2O3/Fe3O4 composite nanofibrous adsorbent was prepared by electrospinning process and its application for the removal of nitrate and phosphate were compared with chitosan/Al2O3/Fe3O4 composite bead adsorbent. The influence of Al2O3/Fe3O4 composite content, pH, contact time, nitrate and phosphate initial concentrations and temperature on the nitrate and phosphate sorption using synthesized bead and nanofibrous adsorbents was investigated in a single system. The reusability of chitosan/Al2O3/Fe3O4 composite beads and nanofibers after five sorption-desorption cycles were carried out. The Box-Behnken design was used to investigate the interaction effects of adsorbent dosage, nitrate and phosphate initial concentrations on the nitrate and phosphate removal efficiency. The pseudo-second-order kinetic model and known Freundlich and Langmuir isotherm models were used to describe the kinetic and equilibrium data of nitrate and phosphate sorption using chitosan/Al2O3/Fe3O4 composite beads and nanofibers. The influence of other anions including chloride, fluoride and sulphate on the sorption efficiency of nitrate and phosphate was examined. The obtained results revealed the higher potential of chitosan/Al2O3/Fe3O4 composite nanofibers for nitrate and phosphate compared with chitosan/Al2O3/Fe3O4 composite beads.

Removal of Pb(II) and Cr(VI) ions from aqueous solutions using chitosan/cobalt ferrite nanofibrous adsorbent

In the present study, the chitosan/cobalt ferrite nanofibrous adsorbent was produced via electrospinning process and its application for the removal of Pb(II) and Cr(VI) ions from aqueous systems was investigated. The cobalt ferrite nanoparticles were synthesized via convectional hydrothermal method and were characterized using XRD, SEM and TEM analysis. The influence of sorption parameters in a batch mode including cobalt ferrite content, pH, contact time, metal ions initial concentration and temperature on the sorption efficiency of Pb(II) and Cr(VI) ions was evaluated. The kinetic data were fitted using pseudo-first-order and pseudo-second-order kinetic models and the isotherm models including Freundlich, Langmuir and Redlich-Peterson were used to describe the equilibrium data of Pb(II) and Cr(VI) sorption using synthesized nanofibrous adsorbent. Thermodynamic parameters investigation showed the spontaneous and endothermic sorption of Pb(II) and Cr(VI) ions. The Pb(II) and Cr(VI) sorption efficiency was also examined during five sorption-desorption cycles by regeneration of nanofibers via 1 M HNO3. The simultaneous influence of metal ions initial concentration on the Pb(II) and Cr(VI) sorption in a binary system was also investigated.

Polyethylenimine nanofibrous adsorbent for highly effective removal of anionic dyes from aqueous solution

We prepared a nanofibrous adsorbent for anionic dye removal from aqueous solution by electrospinning a modified polyethylenimine (m-PEI) and polyvinylidene fluoride (PVDF) blend. The electrospun nanofibrous adsorbent was confirmed to be a nanoscale, porous material with a positively charged surface; these characteristics are quite beneficial for anionic contaminant adsorption. Experimental adsorption of an anionic dye, methyl orange (MO), demonstrates that this adsorbent can rapidly remove MO from aqueous solution; its maximum adsorption capacity was 633.3 mg g−1, which is much higher than that of previously reported adsorbents. After immersion in a basic solution, the adsorbent was well regenerated and showed good recyclability. The adsorption performance of the nanofibrous adsorbent is greatly influenced by the temperature, initial MO concentration, and pH of the solution. We further found that MO adsorption onto the adsorbent can be described well by the pseudo-second-order kinetic model and Langmuir isotherm model. Weber-Morris plots suggested that the adsorption of MO onto the nanofibrous mat was affected by at least film diffusion and intraparticle diffusion. This study indicates that nanofibrous PEI composite mats could be promising for treatment of wastewater containing anionic dye.

Synergistic nanofibrous adsorbent for uranium extraction from seawater

A nanofibrous adsorbent containing dual-ligands with a synergistic effect of uranyl adsorption from simulated seawater was fabricated by a parallel-blend electrospinning method.

Electrospun nanofibrous polyethylenimine mat: a potential adsorbent for the removal of chromate and arsenate from drinking water

A nanofibrous adsorbent for sub-ppm level chromate and arsenate removal from drinking water has been fabricated via an electrospinning technique.