ABSTRACT
PtRu catalyst is a promising anodic catalyst for direct methanol fuel cells (DMFCs) but the slow reaction kinetics reduce the performance of DMFCs. Therefore, this study attempts to improve the performance of PtRu catalysts by adding nickel (Ni) and iron (Fe). Multiwalled carbon nanotubes (MWCNTs) are used to increase the active area of the catalyst and to improve the catalyst performance. Electrochemical analysis techniques, such as energy dispersive X-ray spectrometry (EDX), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and X-ray photoelectron spectroscopy (XPS), are used to characterize the kinetic parameters of the hybrid catalyst. Cyclic voltammetry (CV) is used to investigate the effects of adding Fe and Ni to the catalyst on the reaction kinetics. Additionally, chronoamperometry (CA) tests were conducted to study the long-term performance of the catalyst for catalyzing the methanol oxidation reaction (MOR). The binding energies of the reactants and products are compared to determine the kinetics and potential surface energy for methanol oxidation. The FESEM analysis results indicate that well-dispersed nanoscale (2-5 nm) PtRu particles are formed on the MWCNTs. Finally, PtRuFeNi/MWCNT improves the reaction kinetics of anode catalysts for DMFCs and obtains a mass current of 31 A g(-1) catalyst.
Subject(s)
Catalysis , Electric Power Supplies , Methanol/chemistry , Electrodes , Iron/chemistry , Microscopy, Electron, Scanning , Nanotubes, Carbon/chemistry , Nickel/chemistry , Photoelectron Spectroscopy , Spectrometry, X-Ray Emission , X-Ray DiffractionABSTRACT
The treatment of heart failure in pregnant women is more difficult than in non-pregnant women, and should always involve a multidisciplinary team approach. Knowledge required includes hemodynamic changes in pregnancy and the resultant effect on women with pre-existing or pregnancy-related cardiovascular disease, cardiovascular drugs in pregnancy, ethical issues and challenges regarding saving mother and baby. In addition, women having high risk cardiac lesions should be counselled strongly against pregnancy and followed up regularly. Pregnancy with heart failure is an important issue, demanding more comprehensive studies.
Subject(s)
Heart Failure/therapy , Pregnancy Complications, Cardiovascular/therapy , Counseling/methods , Delivery, Obstetric/methods , Early Diagnosis , Female , Heart Failure/diagnosis , Heart Failure/physiopathology , Hemodynamics , Humans , Postnatal Care/methods , Preconception Care/methods , Pregnancy , Pregnancy Complications, Cardiovascular/diagnosis , Pregnancy Complications, Cardiovascular/physiopathology , Pregnancy Outcome , Prenatal Care/methods , Prenatal Diagnosis/methods , Risk Assessment , Risk FactorsABSTRACT
Palm oil mill effluent (POME) is highly polluting wastewater generated from the palm oil milling process. Palm oil mill effluent was used as an electrolyte without any additive or pretreatment to perform electrocoagulation (EC) using electricity (direct current) ranging from 2 to 4 volts in the presence of aluminum electrodes with a reactor volume of 20 L. The production of hydrogen gas, removal of chemical oxygen demand (COD), and turbidity as a result of electrocoagulation of POME were determined. The results show that EC can reduce the COD and turbidity of POME by 57 and 62%, respectively, in addition to the 42% hydrogen production. Hydrogen production was also helpful to remove the lighter suspended solids toward the surface. The production of Al(OH)XHO at the aluminum electrode (anode) was responsible for the flocculation-coagulation process of suspended solids followed by sedimentation under gravity. The production of hydrogen gas from POME during EC was also compared with hydrogen gas production by electrolysis of tap water at pH 4 and tap water without pH adjustment under the same conditions. The main advantage of this study is to produce hydrogen gas while treating POME with EC to reduce COD and turbidity effectively.
