Renewable Biofuel From WastwaterSludges

What’s the Problem?

• Recent innovations in Green Chemistry have led to the discovery that biodiesel fuel can be synthesized from wastewater sludges.

• The formation of this Carbon Neutral Fuel is not yet feasible as the ideal composition of lipid material required to form a commercially available fuel has not been determined.1

*Photo courtesy of ecoseed.org

Hypothesis

The physical properties of these biodiesel products are determined and adjusted via the exact

composition of the fatty acids within the reactant stream.1

Therefore, an Analytical Method can be used to determine the ideal composition of wastewater

reactants in order to create a commercially feasible and renewable fuel from wastewater treatment plants.

Analyte Information &Biodiesel Formation

• The relevant reactants extracted from wastewater sludge are composed of C10 to C18 fatty acids which undergo a transesterification to form a biodiesel fuel.1

• The relative amounts of these fatty acid chains in the reactant stream will tailor octane number, cold flow, and oxidative stability in the biofuel, which are variables of concern for any diesel fuel.2

Shown above is the formation of FAME, one type of biodiesel fuel.

• The relevant analytes are1:• Fatty Oils from wastewater

streams• Fatty Acid Methyl Ester

(FAME)• Fatty Acid Alkyl Ester (FAAE)

• The generic Structure of the Oil and FAME’s are shown here.

Possible Analytical TechniquesTechnique Advantages Disadvantages

CZE/MSAnalytes can be separated based on

charge and size. Low LOD. Yields data on sample composition.

Expensive equipment. Difficult to maintain. Requires complete

separation of fatty oils and acids from contaminants in the aqueous

matrix.

GC/MS3Common in many organic labs.Easy, quick to run and analyze.

Yields data on sample composition.

Expensive equipment.Somewhat difficult to maintain.

Volatility of large fatty acids may not be high enough to be analyzed via

GC/MS (C14 and above)6.

FT-IR3 Cheap, Easy to Maintain, Fast Analysis.

Very bad with determining exact, fractional composition.

UV-VISUseful for many Organic compounds.

Cheap. Provides clear data on characterization.

The analytes in question contain very little conjugation. The fatty acids and FAME would not give a strong signal. UV-Vis also yields little accurate data

on composition.

Analysis of Reactants and Fuel

• In order to obtain the required data, the analytical method chosen must:– Be able to provide fractional composition data, as

well as characterization– Be amenable to large, organic molecules– Not combust the fuel before analysis– Be simple and efficient at running many samples– Be amenable to some impurity in the analyte, as

the analyte in an applied setting would come from wastewater

Method of Choice for Oil and Fuel: CZE/MS

• CZE seperates the analyte based on charge, which will vary slightly with C10-C18 chain length for both reactants and fuel and provide fractional data on composition.7

• Linear Quadrupole MS will provide characterization data on how different reactant compositions form different FAME and FAAE fuels.6

Shown here is the diagram for a standard CZE seperation column.

A Linear Quadropole detector would be the best choice in MS analyzers, as

it would be able to accommodate all of the large organic molecules (100-1000Da) within the

analytes.

Why CZE/MS?• CZE coupled with MS together yield a very low LOD for

simple, quick analysis within minutes.7

• For the given analytes, CZE will separate the various compounds present and it can be directly coupled with MS via ESI off the column.6

• CZE is useful for all reactants present, regardless of volatility, which is distinct from GC/MS.6,7

• The entire apparatus can handle many trials without reset or maintenance.

• This method will provide the necessary data on both composition and characterization accurately and reliably.

Cost vs. Benefit• CZE/MS is a very expensive setup costing anywhere from

$25k to $100k for the apparatus, including maintenance.7

• The biofuels industry is ever-growing and the transportation fuels industry is one of the largest in the world. A single instrument’s cost is minimal when the potential profits from such research could potentially range in billions of dollars per years.1

• GC/MS has similar benefits as CZE/MS, but is slightly less expensive and more commonly found in research labs. For these purposed GC/MS would be acceptable, however is less time efficient and not amenable to all reactants (particularly those of higher molecular weight; C14 and above).6

Conclusion• Wastewater treatment plants may be a viable

source of a new biodiesel fuel via transesterification of lipidic biomass.1

• CZE/MS can be used to quantify the ideal composition of lipidic material in wastewater, so as to produce this biofuel on a commercially viable scale.7

• Although instrument is expensive, transportation fuels is one of the largest single chemical industries in the world and the potential for profit far outweigh the costs, both financial and environmental.1

Implications of New Biodiesel Fuels

• These new diesel Fuels have the potential to replace a significant portion of the transportation fuel currently being used worldwide.

• Because the fuel comes from recycled wastewater, it is 100% carbon neutral.

• This would provide a use for millions of pounds of wastewater sludge which pollutes water and fills landfills every year.1

References1Karbo, D. M. Biodiesel Production from Municipal Fuel Sludges.Energy and Fuels.

[Online]2010. http://pubs.acs.org/doi/pdf/10.1021/ef1001106 (accessed September 12th, 2011).

2Agency for Toxic Substances and Disease Registry, Center for Disease Control. Toxicology Profiles for Fuel Sources. http://www.atsdr.cdc.gov/toxprofiles/tp75-c3.pdf.

3McLafferty, F.W.; et. al. Tandem Fourier Transform Mass Spectroscopy of Large Molecules.Fourier Transform Mass Spectroscopy.[Online]1987, 7, 116-126 http://pubs.acs.org/doi/abs/10.1021/bk-1987-0359.ch007 (accessed October 25th, 2011).

4Holcapek M.; Jandera, P.; Fischer, J. Analysis of Acylglycerols and Methyl Esters of Fatty Acids in Vegetable Oils and in Biodiesel Critical Reviews in Analytical Chemistry. Critical Reviews in Analytical Chemistry. 2001, 31, 1.

5Lu, C.; Wu H.; Chen S.; Kou, H.; Wu, S. Simple and Sensitive Analysis of Long-Chain Free Fatty Acids in Milk by FluorogenicDerivatization and High-Performance Liquid Chromatography. J. Agric. Food Chem., 2002, 50 (1), 71–73.

6Roemling, R.; Itoh S. HILIC–MS - High Resolution and Sensitivity for theAnalysisof Very Polar Compounds. TOSOH Bioscience Application Note. tosohbioscience.com.

7Gonzalez, E; Lasern J.J. Capillary Zone Electrophoresis for the Rapid Screening of Banned Drugs. Electrophoresis. 1994, 15, 240-243.