Che Ku M. Faizal

Review of the effects of additives on biodiesel properties, performance, and emission features

As a renewable, sustainable and alternative fuel for compression ignition engines, biodiesel is widely accepted as comparable fuel to diesel in compression ignition engines. This is due to several factors like decreasing the dependence on imported petroleum; providing a market for the excess production of vegetable oils and animal fats; using renewable and biodegradable fuels; reducing global warming due to its closed carbon cycle by CO2 recycling; increasing lubricity; and reducing substantially the exhaust emissions of carbon monoxide, unburned hydrocarbons, and particulate emissions from diesel engines. However, there is a major drawback in the use of biodiesel as low heating value and NOX tends to be higher. On the other hand, its relatively poor low-temperature flow properties are a characteristic of biodiesel which limits its application. Here, fuel additives become indispensable tools not only to decrease these drawbacks but also to produce specified products that meet the international and regional standards. This article is a literature review of the effect of different additives on biodiesel properties, performance, and emission characteristics. The researches published by different journals are cited preferentially. From these researches, the effect of biodiesel additives on fuel cold flow properties, engine power, fuel economy and emissions including regulated and non-regulated emissions, and the corresponding effect factors were surveyed and analyzed in detail. Varying results of improvement in cold flow properties have been obtained by using different additives. Similarly, different additives were used by different researchers to improve the performance of a compression ignition engine and its emissions. This review was taken up to identify the various additives used to improve the cold flow properties of biodiesels and improve the performance of a diesel engine and its emissions while using additive blended biodiesels. The review concludes that the additive usage in biodiesel is inseparable both for improving the cold flow properties and for better engine performance and emission control. Further research is needed to develop biodiesel specific additives.

Hybrid molecularly imprinted membranes for targeted tocopherol: uses of cross-linked copolymer particles prepared by surfactant-free dispersion technique.

Alpha-tocopherol (alpha-Toc) targeted membrane adsorbents were prepared by mixing alpha-Toc imprinted particles in polysulfone (PSf) scaffold. The alpha-Toc imprinted particles were prepared with high-shear dispersion copolymerization of alpha-Toc methacrylate (alpha-TMA) and divinylbenzene (DVB) in toluene and water in the agitation range of 300-13,500 rpm. The alpha-Toc groups in resultant imprinted particles were hydrolyzed with 2 M HCl and then the polymers were embedded in PSf membranes by phase inversion technique. The membrane exhibited good selective binding of alpha-Toc with high separation factors to its analogs.

Molecular imprinting membrane having calix[4]resorcarenes moieties for selective separation of α-tocopherol

A novel type of molecular imprinted membrane was prepared from the complexation solution of α-tocopherol (α-Toc) template and calix[4]resorcarenes host with PSf as scaffold polymer by phase inversion technique. The adsorption properties were tunable by slight modification of the calix[4]resorcarenes unit, whereby the recognition of the α-tocopherol towards its analogues by permselective experiments was achieved.

Microbial lipid extraction from Lipomyces starkeyi using irreversible electroporation

The aim of the study was to investigate the feasibility of using irreversible electroporation (EP) as a microbial cell disruption technique to extract intracellular lipid within short time and in an eco‐friendly manner. An EP circuit was designed and fabricated to obtain 4 kV with frequency of 100 Hz of square waves. The yeast cells of Lipomyces starkeyi (L. starkeyi) were treated by EP for 2‐10 min where the distance between electrodes was maintained at 2, 4, and 6 cm. Colony forming units (CFU) were counted to observe the cell viability under the high voltage electric field. The forces of the pulsing electric field caused significant damage to the cell wall of L. starkeyi and the disruption of microbial cells was visualized by field emission scanning electron microscopic (FESEM) image. After breaking the cell wall, lipid was extracted and measured to assess the efficiency of EP over other techniques. The extent of cell inactivation was up to 95% when the electrodes were placed at the distance of 2 cm, which provided high treatment intensity (36.7 kWh m−3). At this condition, maximum lipid (63 mg g−1) was extracted when the biomass was treated for 10 min. During the comparison, EP could extract 31.88% lipid while the amount was 11.89% for ultrasonic and 16.8% for Fentons reagent. The results recommend that the EP is a promising technique for lowering the time and solvent usage for lipid extraction from microbial biomass.

Characterization of Blended Biodiesel Fuel Properties with Small Portion of Butanol as a Fuel Additive

The increasing energy demand challenge, in addition to the crises of mineral oils depletion that becoming a very serious topic. As the main fuel used in energy production for all scopes of life now is the fossil fuels, there is an urgent need to find out an alternative fuel to fulfill the energy demand of the world. The feasibility of biodiesel production from palm oil was investigated with respect to its fuel properties and blending characteristics with petroleum diesel. Though biodiesel can replace diesel satisfactorily, problems related to fuel properties persist. In this study an oxygenated additive butanol (BU) was added to palm oil biodiesel (POME)-diesel blend B50 (50% POME + 50% diesel) in the ratios of 1%, 3%, 5% and 7% and tested for their properties improvement. The results showed slight improvement in acid value, significant viscosity and density. Maximum decrease in pour point by 6 °C at 5% butanol, on the other hand maximum decrease in energy contenent about 11% at 7% butanol compare to blended fuel B50.

Influence of 1-Butanol Additives on Palm Biodiesel Fuel Characteristics and Low Temperature Flow Properties

Diesel engines are widely used in almost all professions and cannot be dispensed with in the near future. Now the fossil fuels which are mainly used in diesel engines are depleting continually accompanied by increasing consumption and prices, there is the need to find alternative fuel to fulfil the worlds energy demand. Alternative fuels like biodiesel, are being used as effective alternative for diesel. The feasibility of biodiesel production from palm oil was investigated with respect to its fuel properties. Though biodiesel can replace diesel satisfactorily, problems related to fuel properties persist. In this study an oxygenated additive 1-butanol (BU) was blended with palm oil biodiesel (POME) in the ratios of 1%, 3%, 5% and 7% and tested for their properties improvement. These blends were tested for energy content and various fuel properties according to ASTM standards. Qualifying of the effect of additive on palm biodiesel fuel properties can serve the researchers who work on biodiesel fuels to indicate the fuel suitability for diesel engines according to fuel standards. Blends of BU in POME resulted in an improvement in acid value, viscosity, density and pour point with increasing content of BU in the blend. Further improvement in the pour point temperature of the palm oil methyl esters 1-butanol blends (B-BU) at 7°C can be achieved by adding 7% BU additive to POME, accompanied by 8.07% decrease in energy content of biodiesel.

Effect of VIPS fabrication parameters on the removal of acetic acid by supported liquid membrane using a PES–graphene membrane support

In this study, the removal of acetic acid by supported liquid membrane (SLM) using hybrid polyethersulfone (PES)–graphene membrane prepared by vapor induced phase separation (VIPS) was investigated. The effects of graphene loading, coagulation bath temperature, air exposure time, and air humidity on the morphology, mechanical strength, porosity, and contact angle of the membrane were analyzed. The performance and stability of the hybrid membrane as a SLM support for acetic acid removal were studied. The best PES–graphene membrane support was produced at a coagulation bath temperature of 50 °C, an air exposure time of 30 s and air humidity of 80%. The fabricated membrane has a symmetrical micropore cellular structure, high porosity and high contact angle. Under specific SLM conditions, almost 95% of acetic acid was successfully removed from 10 g L−1 aqueous acetic acid solution. The hybrid membrane remains stable for more than 116 h without suffering any membrane breakage during the continuous SLM process.

Removal of Acetic Acid from Aqueous Solution by Polyethersulfone Supported Liquid Membrane

Lignocellulosic biomass can be converted to biofuel, which is one of the renewable energy. To achieve this purpose, acid hydrolysis was used to hydrolyse lignocellulosic materials to fermentable sugars. However, acetic acid, a major inhibitory compound was released during the acid hydrolysis process. Existence of acetic acid significantly suppressed fermentative organisms and decreased the production of ethanol. It is necessary to remove acetic acid inhibitor from biomass hydrolysate prior to the fermentation process. Selective removal of acetic acid from aqueous solution was attempted by using supported liquid membrane (SLM) system based on tri-n-octylamine carrier and sodium hydroxide stripping phase. Polyethersulfone (PES) membrane was prepared by vapour induced phase separation method and used as a matrix support in SLM process. Effects of PES membrane thickness, types of diluent, and flow rate of feed phase were tested. Under favourable condition, almost 86 % of acetic acid was successfully removed from the aqueous solution. The PES SLM system remained stable for 8 h of extraction without any breakage.