Garry Nathaniel Barona | Myongji University (original) (raw)

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Papers by Garry Nathaniel Barona

Research paper thumbnail of Negatively charged poly(vinylidene fluoride) microfiltration membranes by sulfonation

Journal of Membrane Science, Mar 1, 2007

Research paper thumbnail of Effect of methanol on plasticization and transport properties of a perfluorosulfonic ion-exchange membrane

Journal of Power Sources, 2011

The transport properties of a perfluorosulfonic acid membrane swollen in different concentrations... more The transport properties of a perfluorosulfonic acid membrane swollen in different concentrations of aqueous methanol mixtures are investigated. Solvent uptake, proton conductivity and methanol permeability of a commercial Nafion ® 117 membrane are evaluated at different methanol concentrations. Small-angle X-ray scattering analysis is performed to study the morphological effects on the formation of ionic clusters created by aqueous methanol mixtures. It is concluded that the observed decrease in proton conductivity and increase in methanol permeability are associated with morphological transitions as well as with the size of the ion cluster, as determined by the concentration of methanol in the test mixture. Wide-angle X-ray scattering studies indicate that the crystalline region is deformed by absorbed methanol; the size of crystalline domains and the crystallinity change with methanol concentration due to plasticization. Absorbed methanol also degrades the mechanical properties, as witnessed by tensile strength measurements.

Research paper thumbnail of High permeate flux of PVA/PSf thin film composite nanofiltration membrane with aluminosilicate single-walled nanotubes

Journal of Colloid and Interface Science, 2012

A new type of thin film nanocomposite (TFN) membranes for nanofiltration was successfully prepare... more A new type of thin film nanocomposite (TFN) membranes for nanofiltration was successfully prepared by incorporating aluminosilicate single-walled nanotubes (SWNTs) within the poly(vinyl alcohol) (PVA) matrix. The nanocomposite PVA film was composed of well dispersed synthesized aluminosilicate SWNT with up to 20% volume fraction cast on a polysulfone support. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) revealed that the TFN membranes have characteristic bands at 920-1010 cm À1 corresponding to SiAOH and SiAOAAl stretching vibration of the aluminosilicate SWNT. This insinuated the successful incorporation of aluminosilicate SWNT into the polymer matrix, which was further confirmed and quantified by X-ray photoelectron spectroscopy (XPS). The PVA layers, in the range of 0.99-1.36 lm, are free from large defects or cracks as observed in the scanning electron microscopy (SEM) images. The membrane surface hydrophilicity increased as the membrane roughness decreased and as the contact angles decreased from 64.2°to 59.4-50.5°. The increase in water flux is due to the presence of hydrophilic nanotubes. With the incorporation of the aluminosilicate single-walled nanotubes, higher permeate water flux was achieved, while sustaining high rejection of divalent ions (97%) and monovalent ions (59%).

Research paper thumbnail of Interfacial polymerization of polyamide-aluminosilicate SWNT nanocomposite membranes for reverse osmosis

Research paper thumbnail of Effect of surface charge on hydrophilically modified poly(vinylidene fluoride) membrane for microfiltration

Desalination, 2011

... Permissions & Reprints. Effect of surface charge on hydrophilically modified poly(vinylid... more ... Permissions & Reprints. Effect of surface charge on hydrophilically modified poly(vinylidene fluoride) membrane for microfiltration. Man Jae Han a , Garry Nathaniel B. Baroña a and Bumsuk Jung low asterisk , a , E-mail The Corresponding Author. ...

Research paper thumbnail of High performance thin film composite polyamide reverse osmosis membrane prepared via m-phenylenediamine and 2,2′-benzidinedisulfonic acid

Desalination, 2012

Thin film composite (TFC) polyamide membranes for reverse osmosis (RO) were successfully prepared... more Thin film composite (TFC) polyamide membranes for reverse osmosis (RO) were successfully prepared via interfacial polymerization of m-phenylenediamine (MPD), 2,2′-benzidinedisulfonic acid (BDSA) and trimesoyl chloride (TMC) on a polysulfone support. The physico-chemical characteristics of the membranes were determined using ATR-FTIR, XPS, zeta potential measurement, SEM and AFM. Membrane performance experiments were investigated using NaCl and MgCl 2 salt solutions. The near region spectra show that the active layer of TFC membrane is an aromatic polyamide, with carboxyl and amino groups, as seen in the ATR-FTIR result. The sulfonyl group addition from the BDSA monomer is evident from the higher sulfur concentration as illustrated in the XPS results and due to more negative zeta potential values. Also, the SEM and AFM pictures show that the surface morphology became smoother as the BDSA content was increased. Due to the modification of the active layer, pure water permeability and rejection of NaCl and MgCl 2 salts were significantly enhanced.

Research paper thumbnail of Effect of surface charge on hydrophilically modified poly (vinylidene fluoride) membrane for microfiltration

Desalination, 2010

... Permissions & Reprints. Effect of surface charge on hydrophilically modified poly(vinylid... more ... Permissions & Reprints. Effect of surface charge on hydrophilically modified poly(vinylidene fluoride) membrane for microfiltration. Man Jae Han a , Garry Nathaniel B. Baroña a and Bumsuk Jung low asterisk , a , E-mail The Corresponding Author. ...

Research paper thumbnail of Negatively charged poly(vinylidene fluoride) microfiltration membranes by sulfonation

Journal of Membrane Science, Mar 1, 2007

Research paper thumbnail of Effect of methanol on plasticization and transport properties of a perfluorosulfonic ion-exchange membrane

Journal of Power Sources, 2011

The transport properties of a perfluorosulfonic acid membrane swollen in different concentrations... more The transport properties of a perfluorosulfonic acid membrane swollen in different concentrations of aqueous methanol mixtures are investigated. Solvent uptake, proton conductivity and methanol permeability of a commercial Nafion ® 117 membrane are evaluated at different methanol concentrations. Small-angle X-ray scattering analysis is performed to study the morphological effects on the formation of ionic clusters created by aqueous methanol mixtures. It is concluded that the observed decrease in proton conductivity and increase in methanol permeability are associated with morphological transitions as well as with the size of the ion cluster, as determined by the concentration of methanol in the test mixture. Wide-angle X-ray scattering studies indicate that the crystalline region is deformed by absorbed methanol; the size of crystalline domains and the crystallinity change with methanol concentration due to plasticization. Absorbed methanol also degrades the mechanical properties, as witnessed by tensile strength measurements.

Research paper thumbnail of High permeate flux of PVA/PSf thin film composite nanofiltration membrane with aluminosilicate single-walled nanotubes

Journal of Colloid and Interface Science, 2012

A new type of thin film nanocomposite (TFN) membranes for nanofiltration was successfully prepare... more A new type of thin film nanocomposite (TFN) membranes for nanofiltration was successfully prepared by incorporating aluminosilicate single-walled nanotubes (SWNTs) within the poly(vinyl alcohol) (PVA) matrix. The nanocomposite PVA film was composed of well dispersed synthesized aluminosilicate SWNT with up to 20% volume fraction cast on a polysulfone support. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) revealed that the TFN membranes have characteristic bands at 920-1010 cm À1 corresponding to SiAOH and SiAOAAl stretching vibration of the aluminosilicate SWNT. This insinuated the successful incorporation of aluminosilicate SWNT into the polymer matrix, which was further confirmed and quantified by X-ray photoelectron spectroscopy (XPS). The PVA layers, in the range of 0.99-1.36 lm, are free from large defects or cracks as observed in the scanning electron microscopy (SEM) images. The membrane surface hydrophilicity increased as the membrane roughness decreased and as the contact angles decreased from 64.2°to 59.4-50.5°. The increase in water flux is due to the presence of hydrophilic nanotubes. With the incorporation of the aluminosilicate single-walled nanotubes, higher permeate water flux was achieved, while sustaining high rejection of divalent ions (97%) and monovalent ions (59%).

Research paper thumbnail of Interfacial polymerization of polyamide-aluminosilicate SWNT nanocomposite membranes for reverse osmosis

Research paper thumbnail of Effect of surface charge on hydrophilically modified poly(vinylidene fluoride) membrane for microfiltration

Desalination, 2011

... Permissions & Reprints. Effect of surface charge on hydrophilically modified poly(vinylid... more ... Permissions & Reprints. Effect of surface charge on hydrophilically modified poly(vinylidene fluoride) membrane for microfiltration. Man Jae Han a , Garry Nathaniel B. Baroña a and Bumsuk Jung low asterisk , a , E-mail The Corresponding Author. ...

Research paper thumbnail of High performance thin film composite polyamide reverse osmosis membrane prepared via m-phenylenediamine and 2,2′-benzidinedisulfonic acid

Desalination, 2012

Thin film composite (TFC) polyamide membranes for reverse osmosis (RO) were successfully prepared... more Thin film composite (TFC) polyamide membranes for reverse osmosis (RO) were successfully prepared via interfacial polymerization of m-phenylenediamine (MPD), 2,2′-benzidinedisulfonic acid (BDSA) and trimesoyl chloride (TMC) on a polysulfone support. The physico-chemical characteristics of the membranes were determined using ATR-FTIR, XPS, zeta potential measurement, SEM and AFM. Membrane performance experiments were investigated using NaCl and MgCl 2 salt solutions. The near region spectra show that the active layer of TFC membrane is an aromatic polyamide, with carboxyl and amino groups, as seen in the ATR-FTIR result. The sulfonyl group addition from the BDSA monomer is evident from the higher sulfur concentration as illustrated in the XPS results and due to more negative zeta potential values. Also, the SEM and AFM pictures show that the surface morphology became smoother as the BDSA content was increased. Due to the modification of the active layer, pure water permeability and rejection of NaCl and MgCl 2 salts were significantly enhanced.

Research paper thumbnail of Effect of surface charge on hydrophilically modified poly (vinylidene fluoride) membrane for microfiltration

Desalination, 2010

... Permissions & Reprints. Effect of surface charge on hydrophilically modified poly(vinylid... more ... Permissions & Reprints. Effect of surface charge on hydrophilically modified poly(vinylidene fluoride) membrane for microfiltration. Man Jae Han a , Garry Nathaniel B. Baroña a and Bumsuk Jung low asterisk , a , E-mail The Corresponding Author. ...