Carbon Nanotubes for Dyes Removal

Mallakpour, Shadpour; Rashidimoghadam, Shima

doi:10.1016/b978-0-12-814132-8.00010-1

Cited by 51 publications

(18 citation statements)

References 75 publications

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“…Starch‐based polymer systems, such as thermoplastic starches (TPS), polymer blends prepared from TPS and biodegradable polymers, or composites of polymer TPS‐containing blends and small amounts of inorganic nanomaterials, belong in the group of advanced biodegradable polymer materials which have been broadly investigated for a longer time 1–6 . Native starch, which consists largely of linear amylose and highly‐branched amylopectin densely packed into the form of semi‐crystalline granules, has to be plasticized usually in a separate step before preparation of the starch‐based polymer systems with mechanical, thermal, barrier and other properties required for their practical applications.…”

Section: Introductionmentioning

confidence: 99%

Aging‐induced structural relaxation in cornstarch plasticized with urea and glycerol

Smidova

Šoltýs

Hronský

et al. 2020

J of Applied Polymer Sci

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In present work structural properties and aging of thermoplastic starches prepared by plasticization of cornstarch with urea, glycerol and their mixtures are studied using solid‐state 1H NMR and 13C NMR spectroscopy and WAXS measurements. Broad line 1H NMR spectra reveal phase separation of plasticizers during aging of the samples with the same or higher relative amount of glycerol than the amount of urea. Glycerol in the TPS samples induces motion of starch chain segments, the mobility of which depends on the relative amount of glycerol. At the scale of nm, formation of B‐type crystallites in the samples containing glycerol and also of single‐helical crystallinity in all samples is observed during one‐year aging through cross‐polarization magic angle spinning 13C NMR spectra. Urea, when used as the sole plasticizer, prevents the ordering of starch chains in B‐type crystallites. WAXS diffractograms show that regular crystals do not form in any of the samples.

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Section: Introductionmentioning

confidence: 99%

Aging‐induced structural relaxation in cornstarch plasticized with urea and glycerol

Smidova

Šoltýs

Hronský

et al. 2020

J of Applied Polymer Sci

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“…Accordingly, despite the presence of hydroxyl functionalities, pure PVA films were totally deficient in Cr (VI) adsorption. Since hydroxyl groups are involved in the cross‐linking reaction between GA and PVA, it can be hypothesized that the adsorption capacity of PVA was depleted due to the significant reduction in the number of active sites after cross‐linking 12,21 . Likewise, only a limited capacity was detected for pure CS membrane even though the structure of CS involves a high content of hydroxyl and amine functional groups for the chelation of heavy metal ions 12 .…”

Section: Resultsmentioning

confidence: 99%

“…The enhanced capacity was attributed to the increase in surface area, the change in porous structure and surface charge, magnetic effects, and the increased number of functional groups 11–14 . Moreover, the inclusion of carbon nanotubes into such polymeric matrices has been shown to improve the tensile strength and thermal stability, remarkably 20,21 . The reinforcement effect is due to hydrogen bonding and/or chemical bonding between the matrix and the nanofiller, that is, carbon nanotubes.…”

Section: Introductionmentioning

confidence: 99%

“…Regeneration studies were conducted to evaluate the recyclability of the composite adsorbent. Previous reports on the production of CS/PVA blends and composites doped with different nanofillers have proven that they are highly efficient for a number of applications ranging from adsorption 14,21 to tissue engineering. 20 With this work, an efficient and reusable CS/PVA/a‐MWCNT composite film was presented providing fast uptake of Cr (VI) from aqueous Cr (VI) solution.…”

Section: Introductionmentioning

confidence: 99%

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Fabrication of chitosan/polyvinyl alcohol/amine modified carbon nanotube composite films for rapid chromate removal

Aydin

2020

J of Applied Polymer Sci

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Composite adsorbent films with amine and hydroxyl functionalities were synthesized from chitosan (CS), polyvinyl alcohol (PVA), and amine‐modified carbon nanotubes (a‐MWCNT) by solvent casting method. Weight proportions of CS to PVA and weight percent of a‐MWCNT were optimized to achieve highest chromate removal capacity. Structural characteristics of the composites were investigated using scanning electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, and thermal gravimetric analysis. Accordingly, incorporation of a‐MWCNT to CS/PVA structure resulted in the generation of nanochannels, which enhanced adsorption capacity. Moreover, the composite comprising 0.4% wt. a‐MWCNT provided over 99% of Cr (VI) removal from 50 mg L−1 Cr (VI) solution within five minutes of contact time. Redlich–Peterson and Radke–Prausnitz isotherm models provided the highest conformity to adsorption data. Maximum chromate sorption capacity of CS/PVA/a‐MWCNT composite film was determined as 134.2 mg g−1 being 172% higher than that of CS/PVA. Regeneration was best achieved in 1.0 M NaOH and the composite was shown to retain at least 70% of its original capacity after five consecutive adsorption–desorption cycles.

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“…Therefore, it is necessary to fabricate safe material with a fast and highly efficient ability to protect water resources from dyes and pollutants. As a result of many efforts, adsorption treatment for wastewater dye removal is considered to be a promising candidate strategy which has attracted the interests of many scientists in recent years [7][8][9]. Adsorbents including carbon, activated carbon, carbon nanotubes, graphene oxide, and nanocomposite hydrogels have been used for wastewater dye removal without generating secondary 2.2.…”

Section: Introductionmentioning

confidence: 99%

Novel Superadsorbent Highly Porous Hydrogel Based on Arabic Gum and Acrylamide Grafts for Fast and Efficient Methylene Blue Removal

Elbedwehy

Atta

2020

Polymers

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Environmental pollution with dyes released from industrial effluent is one of the major and most critical problems in the world. To alleviate this issue, advanced and safe materials with fast and highly efficient dye removal should be designed. Great attention has been paid recently to hydrogels based on polysaccharides such as Arabic Gum (AG) grafted with polyacrylamide (PAM) and polyacrylic acid (PAA). These materials combine the merits of natural polymers such as biodegradability and non-toxicity with the high adsorption ability of PAM and PAA towards cationic dyes such as methylene blue (MB). Many previous works have been done to enhance three-dimensional (3D) structure and swelling ability of the graft copolymers by using a crosslinking agent or even adding nanomaterials as a filler inside the hydrogel matrix. However, these additives may negatively affect the adsorption ability, and few previous studies could reach 2000 mg/g of maximum MB capacity removal within a good period of time. In our work, we synthesized partially hydrolyzed polyacrylamide grafted Arabic gum (AG-g-PAM/PAA) to have both amide and carboxylate groups. The modified water dissolved graft product undergoes water in oil (W/O) emulsion using paraffin oil as the continuous phase and Triton X-100 as a stabilizing agent; then, the system was inversed to oil in water (O/W) emulsion by increasing the shear mixing rate and cross-linked using Epichlorohydrin (ECH). The precipitated graft product showed hierarchically interconnected micro and macropores’ sponge like shape with fast water swelling and high MB adsorption capacity (2300 mg g−1) after 45 min at near neutral pH conditions.

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Carbon Nanotubes for Dyes Removal

Cited by 51 publications

References 75 publications

Aging‐induced structural relaxation in cornstarch plasticized with urea and glycerol

Aging‐induced structural relaxation in cornstarch plasticized with urea and glycerol

Fabrication of chitosan/polyvinyl alcohol/amine modified carbon nanotube composite films for rapid chromate removal

Novel Superadsorbent Highly Porous Hydrogel Based on Arabic Gum and Acrylamide Grafts for Fast and Efficient Methylene Blue Removal

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