Mandana Akia

A review on conversion of biomass to biofuel by nanocatalysts

The world’s increasing demand for energy has led to an increase in fossil fuel consumption. However this source of energy is limited and is accompanied with pollution problems. The availability and wide diversity of biomass resources have made them an attractive and promising source of energy. The conversion of biomass to biofuel has resulted in the production of liquid and gaseous fuels that can be used for different means methods such as thermochemical and biological processes. Thermochemical processes as a major conversion route which include gasification and direct liquefaction are applied to convert biomass to more useful biofuel. Catalytic processes are increasingly applied in biofuel development. Nanocatalysts play an important role in improving product quality and achieving optimal operating conditions. Nanocatalysts with a high specific surface area and high catalytic activity may solve the most common problems of heterogeneous catalysts such as mass transfer resistance, time consumption, fast deactivation and inefficiency. In this regard attempts to develop new types of nanocatalysts have been increased. Among the different biofuels produced from biomass, biodiesel has attained a great deal of attention. Nanocatalytic conversion of biomass to biodiesel has been reported using different edible and nonedible feedstock. In most research studies, the application of nanocatalysts improves yield efficiency at relatively milder operating conditions compared to the bulk catalysts.

Acceleration of biodiesel-glycerol decantation through NaCl-assisted gravitational settling: a strategy to economize biodiesel production.

When making biodiesel, slow separation of glycerol; the main by-product of the transesterification reaction, could lead to longer operating times, bigger equipment and larger amount of steel and consequently increased production cost. Therefore, acceleration of glycerol/biodiesel decantation could play an important role in the overall biodiesel refinery process. In this work, NaCl-assisted gravitational settling was considered as an economizing strategy. The results obtained indicated that the addition of conventional NaCl salt decreased the glycerol settling time significantly up to more than five times. However, NaCl inclusion rates of more than 3g to the mixture (i.e. 5 and 10 g) resulted in significantly less methyl ester purity due to the occurrence of miniemulsion phenomenon. Overall, addition of 1g NaCl/100 ml glycerol-biodiesel mixture was found as optimal by accelerating the decantation process by 100% while maintaining the methyl ester purity as high as the control (0 g NaCl).

Utilization of spray-dried nanoporous gamma alumina support in biodiesel production from waste cooking oil

AbstractGamma alumina is one of the widely used supports in catalyst preparation, possessing a high specific surface area and good thermal stability. Spray drying is an efficient way to produce narrow particle size distribution and spherical shape powders. In this study, spray drying method has been implemented to prepare microspherical nanoporous gamma alumina with a high specific surface area. The nanoporous gamma alumina support was utilized in the preparation of various heterogeneous base catalysts. The highest biodiesel yield of 99% was obtained at 6 wt% loading of K/γ-Al2O3 catalyst, using waste cooking oil as feedstock. The obtained results revealed the great potential of the synthesized nanoporous gamma alumina as an effective support for heterogeneous base catalysts preparation in the transesterification reaction.

Optimizing the dehydrogenation catalyst of higher normal paraffins supported on a nanocrystalline gamma alumina

This study presents an optimization of dehydrogenation catalyst components including platinum, indium, and lithium using response surface methodology (RSM). The catalysts were supported on a synthesized nanocrystalline gamma alumina and evaluated in the dehydrogenation reaction of higher normal paraffins (C10–C15). The best catalytic performance was obtained with the following material ratios: 0.22 of Pt, 0.5 of In, and 0.31 of Li. Comparison of the performance of the optimized catalyst to an industrial catalyst showed the improved catalytic activity of the optimized sample. The obtained results revealed the excellent potential of the optimized catalyst in the dehydrogenation reaction of higher normal paraffins.

Texas Sour Orange Juice Used in Scaffolds for Tissue Engineering

Fine fibers of polyhydroxybutyrate (PHB), a biopolymer, were developed via a centrifugal spinning technique. The developed fibers have an average diameter of 1.8 µm. Texas sour orange juice (SOJ) was applied as a natural antibacterial agent and infiltrated within the fibrous membranes. The antibacterial activity against common Gram-positive and Gram-negative bacteria (Staphylococcus aureus and Escherichia coli, respectively) was evaluated as well as cell adhesion and viability. The PHB/SOJ scaffolds showed antibacterial activity of up to 152% and 71% against S. aureus and E. coli, respectively. The cell studies revealed a suitable environment for cell growth and cell attachment. The outcome of this study opens up new opportunities for fabrication of fibrous materials for biomedical applications having multifunctional properties while using natural agents.

An Overview of the Recent Advances in the Application of Metal Oxide Nanocatalysts for Biofuel Production

Fossil fuels are still primary resources of energy supply; however, they are undoubtedly responsible for most of the environmental pollutions. Over the last decades, renewable sources as clean alternative energies have received an increasing deal of attention due to the limitation of fossil fuel resources for reliable fulfillment of future energy demands and to address the environmental crises. Renewable energies predominately include solar, wind, biomass, hydrogen, and geothermal sources. Among these, biofuels derived from biomass are considered as the most promising candidate owing to a number of reasons such as direct conversion of biomass to liquid biofuels. Gases and liquid biofuels can be produced from biomass feedstock by three main approaches: thermochemical, biochemical, and microbiological technologies. Gasification, pyrolysis, liquefaction, hydrolysis, transesterification, and anaerobic digestion are main routes for biomass to biofuel conversion. In all biofuel production processes, developing the highest quality products with an optimized process (in terms of cost, energy consumption, etc.) is desirable which necessitates the exploitation of modern sciences such as nanotechnology. Among various aspects of nanotechnology, over the last several years, utilization of highly active nanocatalysts for biofuel production has been growing quickly. Recent research studies have mainly focused on developing efficient nanocatalysts for improving conversion, accessing milder operating conditions, and lowering the process cost of biofuel production to collectively try to industrialize these green fuels. This chapter summarizes an overview of various biofuel production processes and, moreover, strives to comprehensively discuss metal oxide nanocatalysts used for biofuel production.