Chemistry > Characterization of Algal Organic Matter and their Biofuels Potential in Abu Dhabi, United Arab Emirates

Characterization of Algal Organic Matter and their Biofuels Potential in Abu Dhabi, United Arab Emirates

Algae as Biodiesel Source

von Prof. Dr Fares M. Howari

The need for alternative fuel sources is urgent as evinced ­by the worldwide declining of ­major hydrocarbon reservoirs, the high demand on ­hydrocarbon and associated environmental ­problems. Algae based bio­fuels or biodiesel are among the strongest options to serve as an alter­native source of hydrocarbon. ­Biodiesel burns 50% cleaner than con­ventional petroleum-derived diesel [1] and can be used in any diesel engine with little to no modification [2]. The United Arab Emirates (UAE) has set a goal of reaching 7% of ­energy demand provided by renewable sources by 2030, and algae based fuel are one of the options. UAE especially Abu Dhabi has strong potential for ­biofuel production from ­algae. It is mainly because UAE coast has favorable environment and geological conditions necessary for commercial production of this fuel. It has: 1) large barren coastal landscape, ­­2) plenty of sunlight, 3) saline water, and 4) presence of coastal and inland sabkhas (salt-flat areas) that has thick algal mat cover.

Though bio-fuel is not a new and has been in production in countries like USA and some other European countries; it has been mainly produced from soybean (USA) and rapeseed (European Countries). Producing bio-fuel from algae is relatively a new ­approach which is creating interest among the scientific communities all over the world. Bio-fuel derived from micro-algae has many advantages over bio-fuels ­produced from soybean or rapeseed. Most primarily, algae grow naturally and abundantly in coastal areas near the seas and also in the sabkhas. Unlike soybean or rapeseed, one would not have to water or provide fertilizers to grow algae. This reduces the environmental impact on Earth. By just replicating the natural conditions, algae can be cultivated for production of bio-fuel. Sele­cting the right technique and procedures coupled with the use of appropriate instruments, algal oil can be extracted and thus produce bio-fuels from algae becomes possible. Is this enough? If one sees it from a laboratory point of view, the main aim might be to just successfully extract algal oil no matter how minimal the quantity compared to the raw materials needed. But once investors or industrial engineers want to convert it into a commercial venture, then lot of factors come into play. The most important factor is the yield. This research has two folds the first focus on characterization of algae, and the second assesses the feasibility of algae culture in Abu Dhabi. Highlights from the first part will be presented in this short article.

Objective and application

The objective of this ongoing research is to find out if it is economically viable to harvest the algae growing naturally in Abu Dhabi coastal areas and the sabkhas in ­order to extract oils from them to convert into biofuels. It is therefore necessary to identify and classify the algal species growing naturally in the sabkhas and coastal ­areas of Abu Dhabi to assess their potential as an oil producing crop and ultimately as alternate source of fuel. The main application of this research is to provide investors with facts and figures about the commercial harvesting and production of biofuels in order to show that it can be a profitable entity. There are many species of algae available and each one can provide different quantity of oil for biofuels. It is therefore necessary to harvest those species which can yield large amounts of biofuels. This short article will highlight only the technical part of this ongoing research project that emphases on the quality and characterization of algae organic matter.

Characterization of algal organic matter

The present study assessed the potential of coastal algae in UAE for biofuel potential. Algal samples were collected from irrigation return flow, from sea shore, and mangrove fields. We placed the pieces of algal inside a glass petridishes (14x2cm) and in glass trays (30x22x5cm) wetted the bottom part with tap water to prevent their dehydration and incubated at 25 +/- 10C. To augment the illumination in lab, illuminated stand were designed to enhance algal growth. Dimensions were 200x200x50cm. Frames of the stand were perforated angle post (bolted with shelving arms). Illumination source is 1.2 ± 0.2 Klux light intensity total of 24 long fluorescence tube lights. The shelves of the stand were fixed with 8mm tampered clear glass with the size of 50x100cm. Isolations and purification were done by serial dilution followed by plating and individual colonies are isolated and inoculated. The study focused on green algae and the dark type algae communities that are associated with the Sabkha’s environment (Fig.1–3). Toward this end, the following tasks were carried out: i) isolation of algae culture, ii) screening of algal culture for biodiesel and iii) extraction of biodiesel. The dry mass factor, lipid content, etc were determined. The biomass of algae was measured by counting their amount under a microscope and the ratio of their amount, and other methods reported in literature [3].

The black and organic part of the algal mat from the sabkha’s sediment have been carefully separated and weighed.Then were filled in a cellulose thimble and taken for Soxhlet extraction. We used different solvents for the extraction: 1) chloroform – methanol mixture (2:1 ratio), 2) methanol – chloroform mixture (2:1 ratio), 3) chloroform alone, 4) methanol alone, and 5) hexane. After the extraction, the samples are undertaken for distillation and separated the different types of organic material from the Algal mat samples. The extracts were analyzed using GS/FID (Varian CP-3800GC) as well as with Nicolet FT-IR spectrometer.

The analyses of the FT-IR data show (Fig.4) that the prominent peaks in the functional group region are common in all the given samples [4]. Also the data do not show much absorptions in the finger print region which indicates that the samples are pure, and the profile indicates the presence of:

// Hydroxyl group -OH, characterized by the strong absorption centered around 3423 cm-1

// -CH2 groups of lipids is characterized by the absorption seen around 2521– 2923 cm-1

// -CH3 groups of lipids are characterized by the strong absorption band at 1443 – 1473 cm-1

// Carbonyl group is indicated by the absorption band at 1629–1787 cm-1

The absorption peaks around 1131 –1200 cm-1 indicate the ant symmetric axial stretching vibrations of carbonyl bonds of the ester. The Carbon Preference Index of the studied samples is more than one which indicate immature recent materials. The reported results from the algal mat are very promising and present the algal mat of Abu Dhabi coast as immature source material of hydro­carbon (Fig.5). Currently we are conducting comparisons between the newly grown algae on the designed stands and algal mat samples. Currently, we are conducting different treatment, and it is believed that the algal mat ­potential to yield hydrocarbon can be strengthened after treating algae with CO₂. Thus algae treated CO₂ under controlled and field conditions are under study to be used as a reference point for optimal conditions of large scale projects or for deployment of algae-based technology to Abu Dhabi coasts. Our ongoing bench-scale scale studies are essential in order to design an open pond scenario.

Bibliography
[1] Haas, M.J. et al. (2001). Energy & Fuels 15, 1207–1212
[2] Yarrow N. M. et al. (2007). Production of Biodiesel from Algae applied to Agricultural Wastewater Treatment; http://cfpub.epa.gov/ncer_abstracts/index.cfm/fuseaction/display.abstractDetail/abstract/8087/report/F
[3 ] Liu et al. (1996), Acta Ecol. Sin. 16 2, 195?–?200
[4] Silverstein, R. M. (2005). Spectrometric identification of organic compounds. Hoboken, NJ: John Wiley & Sons.

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