RESUMO
SOx emissions are primarily caused by compounds containing sulfur in petroleum and fuels, which lead to severe air pollution. For this reason, it is necessary to develop a fast and simple desulfurization method in order to comply with ever-increasing environmental regulations. The newly discovered piezo-catalyst nanocomposite CexOy/SrO can convert mechanical energy directly into chemical energy, thereby enabling mechanically oxidative sulfur desulfurization. 320 W of bath sonication were used to polarize and activate the prepared piezo-catalyst nanocomposite CexOy/SrO for sulfur removal from thiophene and dibenzothiophene as model fuels and kerosene as a real fuel. Using uniform and spherical CeO2/SrO nanocomposites resulted in the highest desulfurization rates of 95.4 %, 97.3 %, and 59.7 %, respectively, for thiophene and dibenzothiophene. This study examined the effect of several parameters, such as sulfur concentration, pH of fuel, dosage of CexOy/SrO nanocomposite, power and time of ultrasonic, and shaking time, on the piezo-desulfurization of thiophene (TP) and dibenzothiophene (DBTP). To identify the major active species in piezo desulfurization, radical trapping experiments were conducted. This study investigated the possibility of reusing the catalyst, and the piezo-desulfurization activity that was demonstrated in the removal of TP and DBTP after 11 cycles as well as the ability of the catalyst to remove real fuel even after 14 cycles was promising. As the kinetic results show, the reaction follows the second order with K = 0.0050. Also, thermodynamic results showed the oxidation of sulfide to sulfoxide and sulfoxide is endothermic. Activation energy for second order rate constant is (3.824 Kj/mole). 0.0236 mol-1. Sec-1 was calculated for Arrhenius Constant.
RESUMO
In order to advance desulfurization technology, a new method for excellent oxidative desulfurization of fuel at room temperature will be of paramount importance. As a novel desulfurization method, we developed piezo-catalysts that do not require adding any oxidants and can be performed at room temperature. A microwave method was used to prepare CeO2/Ce2O3/NiOx nanocomposites. Model and real fuel desulfurization rates were examined as a function of synthesis parameters, such as microwave power and time, and operation conditions, such as pH and ultrasonic power. The results showed that CeO2/Ce2O3/NiOx nanocomposites demonstrated outstanding piezo-desulfurization at room temperature for both model and real fuels. Furthermore, CeO2/Ce2O3/NiOx nanocomposites exhibited remarkable reusability, maintaining 79% of their piezo-catalytic activity even after 17 repetitions for desulfurization of real fuel. An investigation of the mechanism of sulfur oxidation revealed that superoxide radicals and holes played a major role. Additionally, the kinetic study revealed that sulfur removal by piezo-catalyst follows a second-order reaction kinetic model.
RESUMO
OBJECTIVES: This study aims at analyzing the dimensions of the burden of out-of-pocket (OOP) health expenditure in rural and urban India between 1999-2000 and 2011-2012. STUDY DESIGN: Consumer Expenditure Survey data of the National Sample Survey for the period of 1999-2000 (55th round), 2004-2005 (61st round), and 2011-2012 (68th round) have been used in this study. METHODS: To analyze the dimension of OOP healthcare expenditure, this study has used headcount measure, which includes change in the percentage of population paying OOP health expenditure, concentration index of headcount, rank-weighted headcount, and gap measures, which includes average per capita gap (health expenditure), mean positive gap, concentration index, and rank-weighted gap for rural, urban, and all India level between 1999-2000 and 2011-2012. RESULTS: The authors have found that a large percentage of the population in rural and urban India is still not reporting health expenditure. There is a huge difference between per capita health expenditure in rural and urban areas during the study period. The percentage of the population that reported OOP health expenditure has increased at the bottom level, but the expenditure got more concentrated toward better-off people in both rural and urban areas of the country in this time period. It is also clear from the results that the concentration of average per capita gap (Co) in rural areas leans towards better-off people more than in urban areas. CONCLUSION: This study advocates for health sector reforms to protect households from the significant burden of expenditure on critical health care.