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Structure and properties of polyacrylonitrile/polystyrene and carbon nanoparticle-based nanocomposite foams

Kausar A.

Advances in Materials Science

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2019

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Vol. 19, nr 1(59)

5--20

EN

In this study, novel polyacrylonitrile/polystyrene (PAN/PS) blend has been prepared and reinforced with carbon nanoparticle to form polyacrylonitrile/polystyrene/carbon nanoparticle (PAN/PS/CNP) nanocomposite foam. Acid-functional carbon nanoparticle (0.1-3 wt.%) was used as nano-reinforcement for PAN/PS blend matrix. 2’-azobisisobutyronitrile was employed as foaming agent. The PAN/PS/CNP nanocomposite foams have been tested for structure, morphology, mechanical properties, thermal stability, non-flammability, water uptake, and toxic ion removal. Field-emission scanning electron microscopy and transmission electron microscopy exposed unique nanocellular morphology owing to physical interaction between the matrix and functional CNP. PAN/PS/CNP 0.1 Foam with 0.1 wt.% nanofiller had compression strength, modulus, and foam density of 41.8 MPa, 22.3 GPa, and 0.9 mgcm−3, respectively. Nanofiller loading of 3wt.% (PAN/PS/CNP 3 Foam) considerably enhanced the compression strength, modulus, and foam density as 68.2 MPa, 37.7 GPa, and 1.9 mgcm−3, respectively. CNP reinforcement also enhanced the initial weight loss and maximum decomposition temperature of PAN/PS/CNP 3 Foam to 541 and 574 ºC, relative to neat foam (T0 = 411 ºC; T10 = 459 ºC). Nanocomposite foams have also shown excellent flame retardancy as V-0 rating and high char yield of up to 57% were attained. Due to hydrophilic nature of functional carbon nanoparticle, water absorption capacity of 3 wt.% nanocomposite foam was 30% higher than that of pristine foam. Moreover, novel foams were also tested for the removal of toxic Pb2+ ions. PAN/PS/CNP 3 Foam has shown much higher ion removal capacity (166 mg/g) and efficiency (99 %) than that of PAN/PS foam having removal capacity and efficiency of 90 mg/g and 45 %, respectively.

2

Removal of Pb(II) ions from aqueous solution using complexation-ultrafiltration

Şahin D., Tascıoglu S.

Polish Journal of Chemical Technology

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2018

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Vol. 20, nr 2

80--84

EN

Ligand-modified micellar-enhanced ultrafi ltration (LM-MEUF) is a membrane technique based on a separation process which can be used for removal of target metals from an aqueous solution. This method involves adding both a metal complexing ligand and surfactant molecule to the aqueous solution under conditions where most of the molecules are present as micelles. This ligand can be attached to the surface of micelles by solubilization and forms the ligand complexes with the metal ion. The aqueous solution is then treated through a membrane which has to be smaller pore sizes than those of the complexes. Hence, permeate water is then purified from the heavy metals. In this study, divalent lead is the target ion in a solution. Filtration experiments were performed with ultrafi ltration membrane system, equipped with a regenerated cellulose membrane with a 5000 Daltons cutoff. The pressure was fixed at 4.0 bar with a permeate flow rate of 500 mL min–1 . Complexes of Pb2+ ions with three ligands were investigated in micellar medium of different surfactants at different pH values to determine the ligands which could provide separation. Different parameters affecting the percentage rejection of the Pb2+ , such as pH and surfactant concentration were also discussed. Results have shown that the maximum percentage of the Pb2+ ions rejection were obtained using sodium dodecyl sulfate (SDS) as a surfactant and dithizone (DZ) as the lead-specifi c ligand. A waste stream sample from a battery plant was subjected to LM-MEUF process in the optimum conditions determined in this study and it was shown that Pb2+ ions in a waste stream could be removed by LM-MEUF effectively.

3

Preparation, characterization and photocatalytic performances of materials based on CS2-modified titanate nanotubes

An H., Hu X., Zhu B., Song J., Zhao W., Zhang S., Huan W.

Materials Science Poland

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2013

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Vol. 31, No. 4

531--542

EN

CS2-modified titanate nanotubes (CS2/TiO2–NTs) are fabricated by reaction of CS2 and Ti–O2Na+ species on titanate nanotubes. Pb2+ ions are coated on the modified nanotubes by ion exchange (Pb/CS2/TiO2–NTs). The products are characterized by means of nitrogen adsorption-desorption isotherms at 77 K (BET method), transmission electron microscopy (TEM), X-ray photoelectron spectrometry (XPS), X-ray diffraction (XRD), atomic absorption spectrometry (AAS), and diffuse reflectance spectroscopy (DRS). The photocatalytic performances of the products are evaluated by monitoring their catalytic activities for degradation of methyl orange under UV light irradiation. The effects of calcination temperature and atmosphere on the photocatalytic performance are investigated. The results reveal that the photocatalytic activities of CS2/TiO2–NTs and Pb/CS2/TiO2–NTs are far higher than that of primary nanotubes, and the optimum calcination temperature is 500 °C under N2 atmosphere. It is also discovered that physically adsorbed Pb2+ ions affect the photocatalytic activity of Pb/CS2/TiO2–NTs obviously. The photocatalytic activity of washed Pb/CS2/TiO2–NTs is higher than that of the unwashed one under the same thermal treatment and reaction conditions.