1925 ISSN 1229-9197 (print version) ISSN 1875-0052 (electronic version) Fibers and Polymers 2015, Vol.16, No.9, 1925-1934 Preparation and Adsorption Behavior of Diethylenetriamine/Polyacrylonitrile Composite Nanofibers for a Direct Dye Removal Arash Almasian, Mohammad Ebrahim Olya*, and Niyaz Mohammad Mahmoodi Department of Environmental Research, Institute for Color Science and Technology, Tehran 1668814811, Iran (Received September 3, 2014; Revised July 27, 2015; Accepted August 2, 2015) Abstract: The diethylenetriamine (DETA)/polyacrylonitrile (PAN) composite nanofibers were prepared by using electrospinning technique. The surface morphology and chemical characterization of PAN/DETA composite nanofibers were investigated using scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. Releasing possibility of DETA from nanofibers was tested by total organic carbon (TOC) analysis. Results indicated that the incorporation of DETA into PAN affects the morphology of nanofibers. In order to hinder DETA releasing, this compound was fixed to the polymer using alkali treatment. The obtained PAN/DETA composite nanofibers were evaluated for adsorption of C.I direct red 80 (DR80). The amount of the dye adsorbed onto the PAN/DETA nanofiber mats was influenced by the initial pH, DETA amount, contact time, and the initial concentration of the dye solutions. The maximal adsorption capacity of the dye on the PAN/DETA nanofiber mats was calculated from the Langmuir model. Keywords: Polyacrylonitrile, Electrospinning, Direct Red 80, Adsorption isotherm, Dye kinetic Introduction Nowadays, stress of water shortages is increased due to deteriorating water quality, urbanization, and climate change and wastewater reclamation. Water reuse is becoming a widely endorsed strategy for augmenting freshwater resources. In this regard, many methods such as adsorption, chemical flocculation, chemical oxidation, froth flotation, ultra filtration, and biological treatment technologies have been employed. Among all, adsorption has been shown to be a highly efficient process due to its sludge-free clean flexible operation, simplicity of design, and complete removal of dyes from dilute solutions. The adsorption properties of adsorbents depend on the type and amount of functional groups of on their surfaces. It was previously found that an adsorbent containing nitrogen-based ligands are effective in forming complexes with metal ions and dyes [1,2]. There are many forms of nano adsorbents in different shapes including cubes, spheres [3], plates [4], and fibers [5]. Nanofiber can give an enormous surface area per unit volume, high porosity, high gas permeability, and small interfibrous pore size due to having diameter between tens and hundreds of nanometer. Among the various methods reported in literatures [6] for producing the nanosized fibers, electrospinning has shown a great deal of attention due to simplicity, convenient, low cost, and ability to produce ultrafine continuous fibers from many polymeric [7] and ceramic [8] materials. One advantage of production of nanofiber mats for application in wastewater treatment is that they can be easily removed from the solutions, which reduces the operation cost. Polyacrylonitrile (PAN), a common and inexpensive commercial polymer, has desirable chemical and thermal properties [9] as well as good solubility in organic solvents [10]. This polymer has extensively been studied for the production of nanofibers by electrospinning process [9]. Since the properties of adsorbents used to remove dyes changes with the solution conditions, the mechanism of adsorption on the adsorbents is also changed significantly, depending on different types of interaction between adsorbents and dyes. Commonly, for this purpose the electrostatic interaction has been identified as the major adsorption mechanism for adsorption of dyes. The combination of polymers and compounds with different functional groups such as carboxyl and amine, enable their utilization as effective adsorbents in dyes removed from wastewater [11]. Previous research works stated PAN as a desirable polymer for electrospinning and subsequent wastewater treatment [12,13]. It is therefore of our interest to investigate the feasibility of using a composite nanofiber mat bearing amine groups for anionic dye removal from wastewater. Some attempts were performed on surface modification of PAN fibers. The amidoximated PAN nanofibers and aminated PAN fibers were studied for ion adsorption by Saeed et al. [11] and Shin et al. [14] respectively. However, no research was reported to investigate the dye removal efficiency of the polyacrylonitrile/diethylenetriamine (PAN/DETA) composite nanofibers. In the present work, PAN/DETA composite nanofiber mat was synthesized and characterized by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The effect of the amount of DETA, the pH, the contact time, and initial dye concentration on the adsorption capacity of a direct dye was examined using a UV-vis spectrophotometer. *Corresponding author: [email protected]DOI 10.1007/s12221-015-4624-3
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1925
ISSN 1229-9197 (print version)
ISSN 1875-0052 (electronic version)
Fibers and Polymers 2015, Vol.16, No.9, 1925-1934
Preparation and Adsorption Behavior of Diethylenetriamine/Polyacrylonitrile
Composite Nanofibers for a Direct Dye Removal
Arash Almasian, Mohammad Ebrahim Olya*, and Niyaz Mohammad Mahmoodi
Department of Environmental Research, Institute for Color Science and Technology, Tehran 1668814811, Iran
(Received September 3, 2014; Revised July 27, 2015; Accepted August 2, 2015)
Abstract: The diethylenetriamine (DETA)/polyacrylonitrile (PAN) composite nanofibers were prepared by usingelectrospinning technique. The surface morphology and chemical characterization of PAN/DETA composite nanofibers wereinvestigated using scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. Releasingpossibility of DETA from nanofibers was tested by total organic carbon (TOC) analysis. Results indicated that theincorporation of DETA into PAN affects the morphology of nanofibers. In order to hinder DETA releasing, this compoundwas fixed to the polymer using alkali treatment. The obtained PAN/DETA composite nanofibers were evaluated foradsorption of C.I direct red 80 (DR80). The amount of the dye adsorbed onto the PAN/DETA nanofiber mats was influencedby the initial pH, DETA amount, contact time, and the initial concentration of the dye solutions. The maximal adsorptioncapacity of the dye on the PAN/DETA nanofiber mats was calculated from the Langmuir model.
Keywords: Polyacrylonitrile, Electrospinning, Direct Red 80, Adsorption isotherm, Dye kinetic
Introduction
Nowadays, stress of water shortages is increased due to
deteriorating water quality, urbanization, and climate change
and wastewater reclamation. Water reuse is becoming a
widely endorsed strategy for augmenting freshwater resources.
In this regard, many methods such as adsorption, chemical
flocculation, chemical oxidation, froth flotation, ultra filtration,
and biological treatment technologies have been employed.
Among all, adsorption has been shown to be a highly
efficient process due to its sludge-free clean flexible operation,
simplicity of design, and complete removal of dyes from
dilute solutions. The adsorption properties of adsorbents
depend on the type and amount of functional groups of on
their surfaces. It was previously found that an adsorbent
containing nitrogen-based ligands are effective in forming
complexes with metal ions and dyes [1,2]. There are many
forms of nano adsorbents in different shapes including
cubes, spheres [3], plates [4], and fibers [5]. Nanofiber can
give an enormous surface area per unit volume, high
porosity, high gas permeability, and small interfibrous pore
size due to having diameter between tens and hundreds of
nanometer. Among the various methods reported in literatures
[6] for producing the nanosized fibers, electrospinning has
shown a great deal of attention due to simplicity, convenient,
low cost, and ability to produce ultrafine continuous fibers
from many polymeric [7] and ceramic [8] materials. One
advantage of production of nanofiber mats for application in
wastewater treatment is that they can be easily removed
from the solutions, which reduces the operation cost.
Polyacrylonitrile (PAN), a common and inexpensive
commercial polymer, has desirable chemical and thermal
properties [9] as well as good solubility in organic solvents
[10]. This polymer has extensively been studied for the
production of nanofibers by electrospinning process [9].
Since the properties of adsorbents used to remove dyes
changes with the solution conditions, the mechanism of
adsorption on the adsorbents is also changed significantly,
depending on different types of interaction between adsorbents
and dyes. Commonly, for this purpose the electrostatic
interaction has been identified as the major adsorption
mechanism for adsorption of dyes.
The combination of polymers and compounds with different
functional groups such as carboxyl and amine, enable their
utilization as effective adsorbents in dyes removed from
wastewater [11]. Previous research works stated PAN as a
desirable polymer for electrospinning and subsequent wastewater
treatment [12,13]. It is therefore of our interest to investigate
the feasibility of using a composite nanofiber mat bearing
amine groups for anionic dye removal from wastewater.
Some attempts were performed on surface modification of
PAN fibers. The amidoximated PAN nanofibers and aminated
PAN fibers were studied for ion adsorption by Saeed et al.
[11] and Shin et al. [14] respectively. However, no research
was reported to investigate the dye removal efficiency of the