Ibrahim S.M.,Hiroshima University |
Ibrahim S.M.,Advanced Material Research Center |
Xu R.,Changzhou University |
Nagasawa H.,Hiroshima University |
And 5 more authors.
RSC Advances | Year: 2014
A promising new triazine-based nitrogen-rich organosilica (TTESPT) membrane has been developed for molecular separation processes in gas (gas separation) and liquid phases (reverse osmosis (RO)). By adjusting the H2O/TTESPT molar ratio, we found a promising technique for tuning the pore network of TTESPT membranes. An increase in the H2O/TTESPT molar ratio from 60 to 240 fully hydrolyzed all the ethoxide groups in the TTESPT membrane, which reduced the size of the pores in the silica pore network. A TTESPT membrane with a high H2O/TTESPT molar ratio exhibited a high degree of selectivity for H2/SF6 (greater than 4000) at a permeation temperature of 200 °C. This membrane also demonstrated high sodium chloride (NaCl) rejection (>98.5%) with water permeability of >1 × 10 -12 m3 m-2 s-1 Pa-1 under operating conditions of 1 MPa and 60 °C during a RO experiment. As the operating temperature was increased from 25 to 60 °C, the NaCl rejection was constant without displaying the characteristic flux deterioration. This showed that the membrane retained a stable hybrid network structure. © 2014 the Partner Organisations.
Peregrino C.P.,Advanced Material Research Center |
Moreno M.V.,Advanced Material Research Center |
Miranda S.V.,Advanced Material Research Center |
Rubio A.D.,Advanced Material Research Center |
Leal L.O.,Advanced Material Research Center
International Journal of Environmental Research and Public Health | Year: 2011
Mercury is considered one of the most toxic elements for plants and animals. Nevertheless, in the Middle East, Asia and Latin America, whitening creams containing mercury are being manufactured and purchased, despite their obvious health risks. Due to the mass distribution of these products, this can be considered a global public health issue. In Mexico, these products are widely available in pharmacies, beauty aid and health stores. They are used for their skin lightening effects. The aim of this work was to analyze the mercury content in some cosmetic whitening creams using the cold vapor technique coupled with atomic absorption spectrometry (CV-AAS). A total of 16 skin-lightening creams from the local market were investigated. No warning information was noted on the packaging. In 10 of the samples, no mercury was detected. The mercury content in six of the samples varied between 878 and 36,000 ppm, despite the fact that the U.S. Food and Drug Administration (FDA) has determined that the limit for mercury in creams should be less than 1 ppm. Skin creams containing mercury are still available and commonly used in Mexico and many developing countries, and their contents are poorly controlled. © 2011 by the authors; licensee MDPI, Basel, Switzerland.
Leal L.O.,Advanced Material Research Center |
Ferrer L.,University of the Balearic Islands |
Forteza R.,University of the Balearic Islands |
Cerda V.,University of the Balearic Islands
TrAC - Trends in Analytical Chemistry | Year: 2011
This review outlines automated methodologies developed for measuring arsenic in environmental samples. We report the state of the art of the most significant methods exploiting multicommutation flow techniques coupled to hydride generation-atomic fluorescence determination. We review analytical methods used and present a comparative evaluation of them. We also discuss the on-line pre-concentration procedure as being of particular interest in the development of fully automated methods. © 2011 Elsevier Ltd.
Idris R.,University Technology of MARA |
Bujang N.H.,Advanced Material Research Center
Advanced Materials Research | Year: 2014
Epoxidized Natural Rubber (ENR50), lithium imide salt, [LiN(SO2CF3)2] with and without solvent were prepared by solvent casting technique. Non solvated polymer electrolyte showed modest ionic conductivity at ambient temperature. To further enhance ionic conductivity a mixed solvent of ethylene carbonate/propylene carbonate was added into the system. Thermal characterization showed that single transition glass temperature (Tg) for all systems and amorphous phase is dominant. DSC traces of non-solvated samples have shown Tg values increased whereas addition of mixed EC/PC solvent into the electrolyte system reduced their values respectively. Impedance measurements for the solvated epoxidized natural rubber (ENR) based electrolyte systems have shown optimal ionic conductivity 10-4 S cm-1 whereas 10-6 S cm-1 for a non-solvated one. ENR electrolyte systems showed similar temperature dependence, which suggests that the conductivity is thermally activated. © (2014) Trans Tech Publications, Switzerland.
Kasa S.N.,University Malaysia Perlis |
Kasa S.N.,Advanced Material Research Center |
Omar M.F.,University Malaysia Perlis |
Nizam I.,Advanced Material Research Center
Materials Science Forum | Year: 2016
Banana stem (BS) was used as the natural cellulose source. It should undergo a pretreatment process which is an alkali treatment and bleaching before continuing with an acid hydrolysis. Then, the Nanocrystalline cellulose (NCC) was synthesized via acid hydrolysis with four different concentrations of sulfuric acid (H2SO4) at 50%, 52%, 54% and 56%, respectively at 50 °C for 1 hour. The influence of acid concentration of morphology, thermal and chemical properties of the NCC was studied. The morphology dimension of the NCC was determined by using field emission scanning electron microscope (FESEM) and thermal stability of the NCC was determined by using thermal gravimetric analysis (TGA). Chemical composition and structural analysis were measured by using Fourier transform infrared (FTIR) and X-ray diffraction (XRD). © 2016 Trans Tech Publications, Switzerland.
Nuruzatulifah A.M.,Advanced Material Research Center |
Nizam A.A.,Advanced Material Research Center |
Ain N.M.N.,Advanced Material Research Center
Materials Today: Proceedings | Year: 2016
The half seeded emulsion polymerization method was employed to encapsulate fluorescent dye, bromocresol purple (BCP) in polystyrene nanoparticles (PSN) to produce dye/polymer composite colorants. The aim of this study was to investigate the morphology and chemical properties of PSN and encapsulated BCP/PSN. The BCP dye was incorporated into polystyrene nanoparticles formulated from styrene and polymer matrices (eg; emulsifier, initiator, crosslinker). The size, size distribution and emulsion stability of the prepared nanoparticles was examined using Dynamic Light Scattering (DLS) test. The morphology and functional group identification was characterized using Scanning Electron Microscope (SEM) and Fourier Transform Infra-red (FTIR), respectively. As a result, SEM images showed that synthesized polystyrene particles were spherical in shape. The size of polystyrene particles was ranging between 40 - 60 nm and a slight growth of the particles size was observed after the encapsulation of dye which ranges 60 - 70 nm. The BCP dye was leached out from a sol-gel/PSN coated film after 180 minutes reaction time due to the solubility of BCP dye at higher pH. © 2016 The Authors.
Ayala A.,Advanced Material Research Center |
Leal L.O.,Advanced Material Research Center |
Ferrer L.,University of the Balearic Islands |
Cerda V.,University of the Balearic Islands
Microchemical Journal | Year: 2012
An automated monitoring system for sulfate, nitrite and nitrate based on sequential injection analysis (SIA) was developed. For nitrite determination the modified Griess-Ilosvay method was used, whereas nitrate was previously reduced to nitrite using a cadmium column followed by nitrite determination. A turbidimetric method was carried out in order to determine sulfate. The results showed that the proposed SIA monitoring system constitutes an effective approach for nitrite, nitrate and sulfate determination since it is able to determine levels required by international agencies that regulate these parameters in water. Detection limits of 0.0207mgNL-1, 0.0022mgNL-1 and 3mgSO4 2-L-1 were obtained for nitrate, nitrite and sulfate, respectively. The developed method offers also typical characteristics of the multicommutated systems, as portability, low reagents consumption and the subsequently minimization of waste generation. The proposed system was successfully applied to drinking water and wastewater samples and validated with a certified river water sample (ION-96.3, LGC Standards). © 2011 Elsevier B.V.
Budin S.,University Technology of MARA |
Hadi M.A.N.,Advanced Material Research Center |
Jaafar T.R.,University Technology of MARA |
Selamat M.A.,Advanced Material Research Center
Key Engineering Materials | Year: 2016
Carbon-copper composites are attractive materials used for electrical applications, such as brushes for engines and generators, slip rings, switches, relays, lugs, contactor and current collector. Various methods can be used to prepare carbon-copper composite. However, powder metallurgy route is seen to be most favorable due to its possibility of producing uniform microstructure and excellent net shape product. In this work, carbon-copper composite is prepared using powder metallurgy route with warm compaction process. The compaction pressure (A), compaction temperature (B), post baking temperature (C) and compaction time (D) were optimized by Taguchi method. Hardness and transverse rupture strength (TRS) were used to assess the effect of warm compaction process. The experimental design is according to the L9 (34) orthogonal array. It is found that the best parameters and their levels are A3B2C3D2 for the main effect of hardness and the best parameters and their levels for TRS is A3B2C3D1. It is also notified that optimized parameters of A3, B2 and C3 are identical for hardness and TRS. However, for parameter D, the best level for hardness is D2 and for TRS is D1. The ANOVA analysis proved that compaction temperature parameter is significant to hardness and TRS value whereas the others parameters are not significant. © 2016 Trans Tech Publications, Switzerland.
Kim S.H.,Korea University |
Son H.J.,Korea Electronic Technology Institute |
Park S.H.,Korea University |
Hahn J.S.,Advanced Material Research Center |
Kim D.H.,Korea University
Solar Energy Materials and Solar Cells | Year: 2016
The stability of slot-die coated flexible organic photovoltaic (OPV) modules with inverted structures of indium tin oxide (ITO)/ZnO/photoactive layer/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/Ag was analyzed under damp heat conditions. The work primarily focused on the understanding of the degradation mechanism of organic photovoltaic modules in very severe operating conditions (85°C/85% relative humidity [rh]). The electrical change of the OPV module was measured as a function of the aging time under damp heat. A rapid drop in the efficiency of the module was observed, mainly caused by the decline of the open-circuit voltage (Voc) and fill factor (FF). We supposed that the degradation of the modules mainly progressed by the oxygen and moisture penetrating the terminals or at the edges of the barrier films. The physical modification of the layers composing the device by degradation was observed; hence, morphological and chemical analyses were conducted. The analyses revealed that Ag atoms migrated to the interlayers of the cell, resulting in the increase of shunt paths; this was the main reason underlying the reduction of Voc and FF of the OPV module under damp heat. The ZnO layer was also etched by the acidic molecules from the diffused PEDOT:PSS polymer. In addition, the performance parameters of several OPV modules were evaluated simultaneously under damp heat conditions for 1000 h. The same lifetime patterns were observed although the initial efficiencies of the modules were diverse. The interpretation of the lifetime patterns and a suggestion for an objective comparison between the modules showing different initial efficiencies were also addressed. © 2015 Elsevier B.V. All rights reserved.
Lee T.,Universiti Sains Malaysia |
Zubir Z.A.,Advanced Material Research Center |
Jamil F.M.,Advanced Material Research Center |
Matsumoto A.,Toyohashi University of Technology |
Yeoh F.-Y.,Universiti Sains Malaysia
Journal of Analytical and Applied Pyrolysis | Year: 2014
Thermochemical reactions viz.combustion and pyrolysis are important processes in the conversion of biomass from agricultural wastes into functional materials activated carbon fibre (ACF). Acid treatment during combustion and pyrolysis leaves a major impact which affects quality and properties of the resulting ACF such as pore size control and surface area enlargement. In this study, carbonisation and activation of empty fruit bunch (EFB) fibre into ACF was carried out using acid treatment assisted combustion and pyrolysis followed by CO2 gas flow. The effects of acid treatment on the physicochemical properties and pore characteristics was studied by applying sulphuric acid and switching the sequence of acid treatment before and after combustion and pyrolysis. Intercalation of sulphuric acid and exfoliation reactions on the acid-treated EFB fibre resulted in a higher thermal degradation rate compared to raw EFB fibre without acid treatment. Higher BET surface area and total pore volume were obtained for ACF samples treated with acid. The higher pore volume is due to the intercalated sulphuric compound which facilitated the removal of volatile matter and generated more pores for adsorption. However, severe acid oxidation could also lead to pore blocking with excess oxygen complexes and creation of limited porosity. The results show that properties of the ACF can be affected by the sequence of the acid treatment depending on the thermochemical process applied. © 2014 Elsevier B.V. All rights reserved.