FORMULATIONS AND CHARACTERISTICS OF VEGETABLE OIL-BASED MICROEMULSION BIOFUELS

Biofuels have been increasingly explored as alternative renewable fuel sources due to the growing global energy demand, petroleum-based fuel depletion, and the negative effects of global exhaust emissions from fossil fuels. There has been a large amount of research on biofuel technologies and development in recent years. Among all types of liquid biofuels, vegetable oils and bio-alcohols have become of special interest since they can be utilized in engines with and/or without modification. Nonetheless, the limitations of their use are the long-term operation problems from high viscosity of vegetable oils and low energy content of bio-alcohols. Transesterification is the most common method to reduce the viscosity of vegetable oils through the chemical reactions with methanol and/or ethanol. Although biodiesel, the product from this process which is also considered as a biofuel, has comparable fuel properties to No.2 diesel, it has cold weather limitations, generates high nitrogen oxide levels in the exhaust gases of some engines, and produces unpurified glycerol as co-product causing disposal problems. Therefore, vegetable oil-based microemulsification has been proposed as a method to reduce the vegetable oil viscosity using low viscous alcohols while eliminating the chemical reaction and avoiding the unpurified glycerol. In addition, vegetable oil-based microemulsion can overcome the immiscibility between alcohol and oil phases. Microemulsions are thermodynamically stable mixtures of water and oil stabilized by surfactant and/or cosurfactants. Owing to their ultralow interfacial tension and high solubilization capacity, microemulsions are enviable for various applications such as food, cosmetic and pharmaceutical, enhanced oil recovery, and biofuel applications. Microemulsion fuels are transparent, single-phase, and thermodynamically stable mixtures where the polar phase is solubilized in reverse micelles occurring in the non-polar phase stabilized by surfactants. In this dissertation, vegetable oil-based microemulsion fuels have been developed and the effects of ambient temperature, surfactants, cosurfactants, alcohols, vegetable oils, and additives on phase behavior have been evaluated. Next, pollutant emission characteristics of products generated by their combustion (soot, CO, and NOx) and fuel properties (i.e., viscosities, and cold flow properties) of selected microemulsion fuel systems on have been evaluated. This work showed that various formulations of vegetable oil-based microemulsion fuels have comparable fuel properties to canola biodiesel, achieve the ASTM standards of No.2 diesel, and produce more favorable pollutant emissions than canola biodiesel and No.2 diesel. Moreover, the ability to achieve temperature robustness was demonstrated for particular cases depending on user considerations (e.g., sustainable, environment-benign, and/or cost-effective considerations). Most importantly, this dissertation provides useful results for further design and development of microemulsion fuels as potential alternatives with the ultimate goal of environmental sustainability

Valorisation of Biowastes for the Production of Green Materials Using Chemical Methods

With crude oil reserves dwindling, the hunt for a sustainable alternative feedstock for fuels and materials for our society continues to expand. The biorefinery concept has enjoyed both a surge in popularity and also vocal opposition to the idea of diverting food-grade land and crops for this purpose. The idea of using the inevitable wastes arising from biomass processing, particularly farming and food production, is, therefore, gaining more attention as the feedstock for the biorefinery. For the three main components of biomass—carbohydrates, lipids, and proteins—there are long-established processes for using some of these by-products. However, the recent advances in chemical technologies are expanding both the feedstocks available for processing and the products that be obtained. Herein, this review presents some of the more recent developments in processing these molecules for green materials, as well as case studies that bring these technologies and materials together into final products for applied usage

Survival and Predictors of Mortality in Acute Kidney Injury Patients Treated with Sustained Low Efficiency Dialysis

Introduction: Sustained low efficiency dialysis (SLED) is an increasingly common treatment option for acute kidney injury (AKI) patients, but there are few studies examining the survival and predictive outcome of this therapy. The study aims to evaluate survival, pre-SLED predictors and complications associated with SLED. Materials and Methods: This was a retrospective cohort study of 91 patients with AKI treated with SLED in a tertiary hospital from January 2014 to August 2018. The primary outcomes were in-hospital and 30-day mortality. The secondary outcomes were the clinical and laboratory pre-SLED characteristics that were associated with survival and complication of SLED. Results: Median survival of AKI patients treated with SLED was 17 days and the 30-day mortality rate was 58%. Pre-SLED serum levels of creatinine (adjusted HR 0.82, 95% CI 0.71x0.94), albumin (adjusted HR 0.57, 95% CI 0.4–0.81), potassium (adjusted HR 1.38, 95% CI 1.1–1.73) and number of SLED (adjusted HR 0.95, 95% CI 0.91-1) served as predictors of survival. Arrhythmia was found 3.3% and intradialytic hypotension in 13.2% of patients. No patient had bleeding complications. Conclusions: Our study found similar in-hospital and 30-day mortality for AKI patients treated with SLED. High pre-SLED levels of serum albumin, creatinine and number of SLED were significantly associated with reduced risk of death and high pre-SLED serum potassium was associated with increased risk of death. These results indicate that SLED is safe treatment, with few haemorrhage and haemodynamic complications. Key words: Acute kidney injury, Predictors, Sustained low efficiency dialysis, Survival</jats:p