Multi-Walled Carbon Nanotubes As Pervaporation Buckypaper Membranes And Catalysts For Etherification Reaction

Asymmetric membranes were prepared by first forming multi-walled carbon nanotube-buckypaper (MWCNT-BP) structures as the pre-selective layer followed by coating the structures with a thin layer of polyvinyl alcohol (PVA) to form novel MWCNT-BP/PVA asymmetric membranes. The resultant asymmetric membranes were applied in the pervaporation process for dehydration of multi-component mixture obtained from an etherification reaction process. The pervaporation results revealed that the asymmetric membranes exhibited two- and four-fold enhancements of the water permeation flux and separation factor, respectively, compared to the pure PVA membrane. This effect was observed due to the hydrophilic group on the purified MWCNTs and the nanochannels of the pre-selective layer, which favour the permeation of water molecules. A solution-diffusion model of Rautenbach was adequately in describing the pervaporation process. In the etherification reaction process study, sulfonated MWCNTs catalyst containing Lewis acid sites was prepared via sulfonation process with sulfuric acid. The catalytic performances of sulfonated MWCNTs catalyst were investigated in the etherification reaction process of tert-butyl alcohol (TBA) with ethanol. The effect of process variables (reaction temperature, reaction time, molar ratio of ethanol to TBA, catalyst loading) on the conversion of TBA, selectivity of ethyl tert-butyl ether (ETBE) and yield of ETBE were investigated using two different approaches: conventional approach and response surface methodology (RSM) approach. In the conventional approach, the optimum reaction conditions consisted of 4 h of reaction time at 140 °C, a molar ratio of ethanol to TBA of 2:1 and a catalyst loading of 3 wt%. The optimum TBA conversion, ETBE selectivity and ETBE yield were 64 %, 68 % and 44 % respectively. On the other hand, the results obtained from RSM approach revealed that individual variables and their interactions affect the etherification reaction significantly. The 4 h reaction at 146 °C, molar ratio of ethanol to TBA of 2.17:1 and 3.26 wt% catalyst loading gave an optimum conversion of TBA of 72 %. Furthermore, the optimum selectivity and yield of ETBE were 60 % and 43 %, respectively. It was interesting to note that similar optimum process variables were obtained from both approaches. Nevertheless, RSM approach provides a better and specific optimum process variables since the values were predicted from model equations. An etherification mechanism was proposed to describe the etherification reaction. The sulfonated MWCNTs catalysts exhibited an insignificant dropped of the catalytic performance after four consecutive experimental runs and it was easily regained after regeneration. Subsequently, the optimized reaction mixture was applied as the feed solution for dehydration of water using the novel asymmetric membrane. The total permeation flux of approximately 7 g/m2∙h, and separation factor of approximately 400 were obtained

Production Of Biodiesel From Jatropha Curcas L. Oil Catalyzed By SO42-/ZrO2

Biodiesel which is derived from non-edible oil such as Jatropha curcas L. oil has a better potential compare to edible oil to replace petroleum-derived diesel fuel as it does not compete with food resources. However, Jatropha curcas L. oil contains high free fatty acids, which is far beyond the limit that can be tolerated by homogeneous alkaline catalyst. Therefore, heterogeneous acid catalyst is required to eliminate soap formation in the product mixture. In this study, two simplified methods to prepare sulfated zirconia loaded on alumina (SZA) catalyst for transesterification of Jatropha curcas L. oil with methanol to biodiesel is reported. The catalysts were prepared by direct sulfation of zirconia oxide method and solvent- free method. The catalysts were characterized by X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), pyridine- FTIR and BET surface area measurement

Palm Oil As Feed Stocks For Biodiesel Production Via Heterogeneous Transesterification: Optimization Study.

Fatty acid methyl ester (FAME) prepared by transesterification process using heterogeneous catalyst has receive a lot of interest lately as a sustainable and reliable source of bio fuel. Apart from that, palm oil, being the worlds’ cheapest edible oil has the economical potential to become the source of FAME

Upcycling of biomass waste from durian industry for green and sustainable applications: An analysis review in the Malaysia context

Durian with high nutritional value is cultivated mainly in tropical countries especially in Southeast Asia. The high annual durian production volume of approximately 350,000 MT in Malaysia has led to the abundance of durian biomass waste. Biochar derived from durian biomass waste has huge potential for sustainable applications in various fields. In this paper, durian biomass waste generation and management system in Malaysia are first discussed. The estimated potential energy available in Malaysia from durian biomass waste is then presented followed by the discussion on the conversion of durian biomass waste into biochar through pyrolysis and hydrothermal carbonization. Applications of durian biochar as catalysts, bio-sorbents for the removal of organic pollutants from wastewater, biocomposite, fertilizers, supercapacitor electrode material, and briquettes have also been reviewed. Moreover, this paper highlights the potential applications of durian biochar-derived biodegradable mulch film and supercapacitor electrode material in Malaysia to tackle both plastic waste and energy storage issues. Besides biochar, production and applications of bio-oil, biogas and other valuable compounds from durian biomass waste are also discussed. Furthermore, the Fourth Industrial Revolution (IR 4.0) on the durian industry in Malaysia which includes Internet of Things (IoT), Big Data and autonomous systems, sustainability assessment tools as well as the challenges are discussed. Based on the work presented, despite Malaysia has great potential in upcycling the durian biomass waste for several applications, more in-depth researches are necessary to further solidify the promising application in the specific field and improve production planning of durian fruit while valorizing durian biomass waste which makes up about 19% of total durian biomass waste from major durian producers from Southeast Asia

Health-status outcomes with invasive or conservative care in coronary disease

BACKGROUND In the ISCHEMIA trial, an invasive strategy with angiographic assessment and revascularization did not reduce clinical events among patients with stable ischemic heart disease and moderate or severe ischemia. A secondary objective of the trial was to assess angina-related health status among these patients. METHODS We assessed angina-related symptoms, function, and quality of life with the Seattle Angina Questionnaire (SAQ) at randomization, at months 1.5, 3, and 6, and every 6 months thereafter in participants who had been randomly assigned to an invasive treatment strategy (2295 participants) or a conservative strategy (2322). Mixed-effects cumulative probability models within a Bayesian framework were used to estimate differences between the treatment groups. The primary outcome of this health-status analysis was the SAQ summary score (scores range from 0 to 100, with higher scores indicating better health status). All analyses were performed in the overall population and according to baseline angina frequency. RESULTS At baseline, 35% of patients reported having no angina in the previous month. SAQ summary scores increased in both treatment groups, with increases at 3, 12, and 36 months that were 4.1 points (95% credible interval, 3.2 to 5.0), 4.2 points (95% credible interval, 3.3 to 5.1), and 2.9 points (95% credible interval, 2.2 to 3.7) higher with the invasive strategy than with the conservative strategy. Differences were larger among participants who had more frequent angina at baseline (8.5 vs. 0.1 points at 3 months and 5.3 vs. 1.2 points at 36 months among participants with daily or weekly angina as compared with no angina). CONCLUSIONS In the overall trial population with moderate or severe ischemia, which included 35% of participants without angina at baseline, patients randomly assigned to the invasive strategy had greater improvement in angina-related health status than those assigned to the conservative strategy. The modest mean differences favoring the invasive strategy in the overall group reflected minimal differences among asymptomatic patients and larger differences among patients who had had angina at baseline

Initial invasive or conservative strategy for stable coronary disease

BACKGROUND Among patients with stable coronary disease and moderate or severe ischemia, whether clinical outcomes are better in those who receive an invasive intervention plus medical therapy than in those who receive medical therapy alone is uncertain. METHODS We randomly assigned 5179 patients with moderate or severe ischemia to an initial invasive strategy (angiography and revascularization when feasible) and medical therapy or to an initial conservative strategy of medical therapy alone and angiography if medical therapy failed. The primary outcome was a composite of death from cardiovascular causes, myocardial infarction, or hospitalization for unstable angina, heart failure, or resuscitated cardiac arrest. A key secondary outcome was death from cardiovascular causes or myocardial infarction. RESULTS Over a median of 3.2 years, 318 primary outcome events occurred in the invasive-strategy group and 352 occurred in the conservative-strategy group. At 6 months, the cumulative event rate was 5.3% in the invasive-strategy group and 3.4% in the conservative-strategy group (difference, 1.9 percentage points; 95% confidence interval [CI], 0.8 to 3.0); at 5 years, the cumulative event rate was 16.4% and 18.2%, respectively (difference, 121.8 percentage points; 95% CI, 124.7 to 1.0). Results were similar with respect to the key secondary outcome. The incidence of the primary outcome was sensitive to the definition of myocardial infarction; a secondary analysis yielded more procedural myocardial infarctions of uncertain clinical importance. There were 145 deaths in the invasive-strategy group and 144 deaths in the conservative-strategy group (hazard ratio, 1.05; 95% CI, 0.83 to 1.32). CONCLUSIONS Among patients with stable coronary disease and moderate or severe ischemia, we did not find evidence that an initial invasive strategy, as compared with an initial conservative strategy, reduced the risk of ischemic cardiovascular events or death from any cause over a median of 3.2 years. The trial findings were sensitive to the definition of myocardial infarction that was used