Biodiesel produced from triglycerides and/or free fatty acid (FFA) by transesterification and esterification has attracted immense attention during the past decades as a biodegradable, renewable and sustainable fuel. Currently, solid... more
Biodiesel produced from triglycerides and/or free fatty acid (FFA) by transesterification and esterification has attracted immense attention during the past decades as a biodegradable, renewable and sustainable fuel. Currently, solid superacid catalysts has proved more efficient and “green” approach due to avoidance of environmental and corrosion problems, and reduce product purification procedures. However, it is less viable economically because the reusability is low due to lack of hydrophilic/hydrophobic balance in reactions that involve the use of inedible feedstock with high water content. Therefore, this study gives a critical review on recent strategies towards efficient and a “greener” production of biodiesel via solid superacid catalysis. The strategies discussed include alkyl-bridged organosilica moieties functionalized hybrid catalysis to improve the hydrothermal stability of superacid catalysts; pre- and in situ water removal; process intensification via temperature profile reduction. The strategies enabled well-defined porosity and excellent hydrophobicity/hydrophilicity balance, which suppressed deactivation by water and glycerol.
The sulfonated reduced graphene oxide (S-rGO) as supports and size-controlled Pt nanoparticles (NPs) for proton exchange membrane fuel cell (PEMFC) catalysts was investigated. The S-rGO was fabricated by a lyophilization-assisted method... more
The sulfonated reduced graphene oxide (S-rGO) as supports and size-controlled Pt nanoparticles (NPs) for proton exchange membrane fuel cell (PEMFC) catalysts was investigated. The S-rGO was fabricated by a lyophilization-assisted method from a liquid mixture of GO and (NH4)2SO4 with a subsequent thermal treatment in inert gas. Sulfonic acid groups were grafted on GO and a reduction of GO was achieved simultaneously. Transmission electron microscope (TEM) results showed a uniform deposition of Pt NPs on S-rGO (Pt/S-rGO) with a narrow particle size distribution ranging from 2 to 5 nm in diameter. A higher catalytic activity of this novel Pt/S-rGO catalyst was revealed in comparison with that of Pt/GO, Pt/rGO and conventional Pt/C catalysts by cyclic voltammetry and oxygen reduction reaction measurements due to an enhanced triphase boundary. Significantly, the Pt/S-rGO catalyst also presented an excellent electrochemical stability. This new catalyst thus holds a great potential application in PEMFCs in terms of enhanced activity and durability.
Proton exchange membranes (PEMs) were developed by radiation induced grafting of styrene onto poly ethylene terephthalate (PET) and linear low density polyethylene (LLDPE) membranes using two steps technique. Subsequent sulfonation on the... more
Proton exchange membranes (PEMs) were developed by radiation induced grafting of styrene onto poly ethylene terephthalate (PET) and linear low density polyethylene (LLDPE) membranes using two steps technique. Subsequent sulfonation on the PET films was conducted by chlorosulfonic acid (ClSO3H). The PET films in 45% styrene solution at 1500 krad dose has found to show the highest grafting (17.4%) in both techniques while the maximum degree of sulfonation was noticed to be 9% with a soaking time 150 minutes. Surface morphology was investigated from scanning electron microgram (SEM). Proton exchange capacity (PEC) was confirmed by pH change in 0.01 M NaCl solution. Optical and electrical characteristics of the PEMs were performed by the measurements of FTIR optical absorption, electrical impedance, and electrical resistance respectively.
"Poly(vinylidene fluoride-co-hexafluoro propylene) is a prospective material for the fabrication of polymer electrolyte membranes (PEMs) for direct methanol fuel cells, primarily due to its low methanol permeability, high mechanical... more
"Poly(vinylidene fluoride-co-hexafluoro propylene) is a prospective material for the fabrication of polymer
electrolyte membranes (PEMs) for direct methanol fuel cells, primarily due to its low methanol permeability,
high mechanical integrity and significantly low cost compared to conventionally used Nafion.
However, low proton conductivity has hindered its independent use; therefore, most studies on this prospective
copolymer have been done by using it in conjunction with Nafion. Nevertheless, partial sulfonation
of this copolymer has resulted in increased proton conductivity while maintaining its low methanol
permeability. Therefore, it seems appropriate that blending this sulfonated copolymer with a second lowcost
component, which can complement its low conductive nature, can result in PEMs with high selectivity.
Use of partially sulfonated polyaniline, as the second component, produced selectivity ratio of
5.85 105 Ss cm3, ion-exchange capacity of 0.71 meq g1, and current density of 90.5 mA cm2 at
+0.2 V and 60 C and corresponding maximum power density of 18.5mWcm2."
