Initial Publication Date: September 28, 2021 | Reviewed: March 10, 2023

Biomass conversion into highly useful chemicals

SAPNA JAIN, Alabama State University
Location: Alabama

Abstract

This CURE-based course aims to provide authentic research experience to undergraduate students to help develop their professional skills, clarify their career path, understand the research process, and gain an understanding of how scientists think. In addition, this course aims to bridge the gap between theoretical knowledge in chemistry and its practical applications in solving real-world problems. It allows students to construct and synthesize their knowledge and skills by applying theoretical knowledge in laboratory research. This CURE introduces the students to biofuels as a source of energy for the future. The students learn a systematic method for catalytic conversion of biomass material to liquid fuel platform chemicals. Efficient and economical conversion of lignocellulosic biomass (LCB) to value-added chemicals has the potential reduce dependence on nonrenewable resources such as fossil fuel. LCB is highly resistant to hydrolysis, and therefore new methods of LCB conversion into glucose and liquid fuel platform chemicals such as 5-hydroxymethylfurfural (HMF) have been widely researched. The emphasis will be on the synthesis of novel zeolite catalysts impregnated with metals and the evaluation their biomass conversion to glucose and HMF. Students design, synthesize, and deduce identities of the biomass conversion products from chemical and spectral clues, and predict reaction products.The total reducing sugar (TRS) is determined using the 3, 5-dinitrisalcylic acid (DNS) array method. The catalysts are characterized using techniques such as Fourier transform infrared (FT-IR), Scanning Electron Microscopy (SEM), Energy dispersive spectroscopy (EDS), Thermogravimetric analysis(TGA), Differential thermal analysis (DTA), and Gas Chromatography-Mass Spectrometry (GCMS).

 

Student Goals

1. Developing hypotheses based on prior knowledge: Students conduct an extensive literature search to design and plan the experiments by analyzing other researchers' work. They learn effective use of research databases such as ScienceDirect, Pubmed, and SCOPUS, and they summarize the outcomes of the existing research results. Students then take an educated guess about how things work. For instance, can metal impregnated ZSM-5 show enhanced pore structure, larger surface area, and acid sites for efficient depolymerization of LCB reaction to produce biofuels? What effects does metal impregnation have on the product selectivity and physicochemical properties of ZSM-5?

2. Testing hypotheses by designing and carrying out experiments: Students with with the instructor to design a methodology and protocols for the experimental work in order to test their hypotheses. Students determine the reaction conditions, such as temperature, solvent, and reaction time, and change only one factor while keeping all other conditions the same.

3. Analyzing data and drawing conclusions: Students evaluate whether the experimental results supported their hypotheses or not. Students then compare and analyze the metal impregnated and plain ZSM-5 catalyst using catalyst characterization data for FT-IR, SEM, EDX, TPD. Likewise, the product yield and selectivity studies will be conducted by DNS and GCMS studies.

Research Goals

1. Synthesize and characterize novel catalysts for enhanced product selectivity and yield optimization: Metal-ZSM-5 catalysts such as Ni-ZSM-5, Co--ZSM-5, Pt-ZSM-5, Cr-ZSM-5, and others that have not been tried for biomass conversion studies are synthesized. Novel catalysts are characterized using the following tools; FTIR, SEM, EDX, and TPD. Based on the initial observation from the catalysts characterization studies, reasonable predictions are made about the outcome of the experiments. For example, will an increase in the acidic site on the catalysts result in enhanced product yield and selectivity? Research plan and protocols are designed in order to conduct adequate experimental studies.

2. Optimize the conditions for biomass conversion into specific platform chemicals: Results are summarized in the context of background research to explain the results and support the conclusion. If the hypothesis was not supported, new hypotheses are developed and new predictions are made based on experimental observations. Changes in the experimental design and/or procedures are proposed as appropriate.

Context

The CURE is designed for a small class size involving up to 15 upper-level students. This is a 4-credit, semester-long course with two Lab sessions of 2:30 hours per week. The prerequisites for the course is the successful completion of Organic Chemistry I & II courses. The overall course goals are for students to:

  1. Understand processes of conversion of feedstock/biomass material to biofuels by biochemical methods.
  2. Understand the theory underlying alternative energy conversion technologies.
  3. Synthesize catalysts and characterization of catalysts by using various instrumentation techniques.
  4. Perform experiments to learn how biofuels other than ethanol can be produced.
  5. Work in a group of 2-3 people on a research project.

Target Audience: Major, Upper Division
CURE Duration: One semester

CURE Design

The main objective of this CURE is to synthesize and characterize novel zeolite-based catalysts and optimize the reaction conditions for biomass conversion into TRS and liquid fuel platform chemicals. Under the instructor's supervision, the students design and perform experiments, analyze the results, draw conclusions, and provide directions for future study. The goal is to develop the students' scientific acumen and develop their familiarity with scientific research. Students are encouraged to make observations, perform an extensive literature search, form a hypothesis, test their hypothesis by experimentation, analyze results, and draw conclusions. After completing this CURE, students will be able to :

  • Identify that what properties of biomass make it a suitable feedstock for biofuel production.
  • Design zeolite-based catalysts for product selectivity and yield optimization. 
  • Plan and carry out simple biomass conversion experiments.
  • Learn to operate instruments, carry out techniques, analyze data, troubleshoot, and draw conclusions.

During the course, students are expected to

  • Participate in class discussions by sharing observations and interpretations, asking questions, and solving problems.
  • Work on the research project in small groups ( 2-3 students/group). Students are advised to select a group leader to oversee their research project. 
  • Observe all laboratory safety protocols and work ethics during the laboratory analysis.
  • Perform laboratory experiments according to established procedures, including keeping a laboratory notebook and writing laboratory reports.
  • Present their research finding as oral or poster presentations. Each group is also expected to give a 15-minute oral or poster presentation followed by 5 minutes of a question-answer session.
  • Write up a detailed group project report, with each group member responsible for completing their part of the report and submitting to the group leader on time to print the final copy. The project report is formatted to follow a typical American Chemical Society Journal. The report must have a title page containing the names of the group members, the title of your research project, the name of the department, and the institution at which the experiment was conducted. Also, the report must contain an abstract, introduction with appropriate background and a minimum of 5 references, detailed experimental, result, and discussion, conclusion, references, and acknowledgment sections.

Core Competencies: Organic Chemistry, Analytical Chemistry.
Nature of Research: Applied Research, Wet Lab.

Tasks that Align Student and Research Goals

Research Goals →
Student Goals ↓

Research Goal 1: Synthesize and Characterize novel catalysts for enhanced product selectivity and yield optimization.
Research Goal 2: Optimize the conditions for biomass conversion into specific platform chemicals.


Student Goal 1: Develop hypotheses based on prior knowledge
1. Identify the methods of preparation of metal impregnated ZSM-5 catalysts from the literature search.
2. Make a reasonable prediction about the likely changes metal impregnation will cause to the structure and function of the ZSM-5 catalyst.
3. Determine the reaction conditions that are most likely to succeed.
1. Identify which solvents will be best suited to effectively dissolve cellulose and disrupt the hydrogen bonding network in the cellulose strands and its reaction media suitability.
2. ZSM-5 inherently possess both Bronsted and Lewis acid sites. Predict whether metal impregnation enhances or reduces these acid sites? Does it enhance or reduce the surface area of the catalyst. Which features in the catalysts are optimal to catalyze and promote hydrolysis of cellulose, isomerization of glucose, and dehydration of fructose to HMF?


Student Goal 2: Testing hypothesis by planning and carrying out experiments
1. Identify the optimal reaction conditions for the synthesis of the novel catalysts. Find out the optimum temperature, the concentration of the metal precursor, and reaction time required to sysnthsize an efficient catalyst.
2. Identify the ideal solvent that will help dissolve cellulose and reduce its crystallinity.
3. Describe the advantages and disadvantages of the chosen methods.
1. Determine the synergy between solvent and metal-catalyst in efficient depolymerization of cellulose to produce total reducing sugar yield (TRS).
2. Determine the optimum temperature, pressure, and concentration for conversion of TRS into liquid fuel platform chemical, HMF.
3. Observe and report how the presence of a particular solvent significantly affects the activation energy of the formation and the decomposition of sugar.
4. Perform hydrolysis of the LCB using a batch reactor, where the optimal conditions for hydrolysis into TRS will be determined.


Student Goal 3: Analyze data and draw conclusions
1. Characterize the novel catalysts using FT-IR to study the effect of metal incorporation into the framework structure of ZSM-5 catalyst.
2. Analyze the changes in the surface characterization of the novel catalysis by SEM. Compare the original ZSM-5 with the metal-impregnated novel catalyst.
3. Perform elemental analysis by EDS.
4. Evaluate the thermal properties by TGA and DTA studies.
1. Determine the amount TRS obtained from the depolymerization of LCB by 3, 5-dinitrisalcylic acid (DNS) array method using UV-Visible spectroscopy.
2. Determine the TRS yield from the calibration curve formed using a four-point concentration of standard glucose solutions.
3. Determine the % TRS yield.
4. Determine the concentration of TRS (fructose, glucose) and liquid fuel platform chemical HMF using GCMS.
5. Determine how solvent helped dissolve cellulose decreased the crystallinity and degree of polymerization, which improved the interaction of catalyst and the substrate
6. Determine how LCB migrates to the active surface of the catalyst to cause the breakdown of the glycosidic bonds to release the sugar monomers.

Instructional Materials

Standard Curve (Microsoft Word 2007 (.docx) bytes Aug30 21)
Evaluation Rubric 2 (Microsoft Word 2007 (.docx) bytes Aug30 21)
Evaluation Rubric 1 (Microsoft Word 2007 (.docx) bytes Aug30 21)

Assessment

Evaluation Rubric-2 (Microsoft Word 2007 (.docx) bytes Aug30 21)
Evaluation Rubric (Microsoft Word 2007 (.docx) bytes Aug30 21)

Instructional Staffing

The instructor prepares the labs with the help of the students. No extra staffing is required.

Author Experience

SAPNA JAIN, Alabama State University

I believe that independent undergraduate research experiences enable students to develop critical thinking skills, form a firm academic foundation, and ultimately pursue a path to career success. However, limited access to research and lack of awareness of the benefits of undergraduate research opportunities exclude many students and cause inequities in the research community. This CURE provides an opportunity to undergraduate students who may not have access to independent research. Biomass conversion into fuels is environmentally friendly and is thought to be one of the most promising alternative energy technologies. In this CURE, students will learn the mechanistic approach of catalytic conversion of select biomass material into liquid fuel platform chemicals.


Advice for Implementation

I have included CUREs before in my Organic Synthetic methods class. I have the following suggestions and observations:

  1. I taught Chemistry majors and the class size was 12 students. I think it worked for me as students were enthusiastic and motivated to try new ideas and do research. 
  2. I planned the experiments with the supplies and instruments available to us.
  3. I used the instruments in some other colleagues' labs and they were quite helpful.
  4. I broke down the various research goals into smaller tasks for the students and gave them clear instructions as to how to proceed with the project.
  5. I made them aware in advance that negative results are also results so that they do not get discouraged.

Iteration

The key to a successful research outcome lies in repetition: returning and referring to the hypothesis, original idea, methods, and data analysis, which helps develop a novel perspective, leads to improvements, and provides a future direction. With respect to this CURE, the idea of impregnating zeolite with metal may result in either of the two things. It could decrease the catalyst's efficiency by decreasing the surface area and thereby decreasing the product yield. Or the metal deposition could enhance the acidic sites, thereby providing the product's selectivity. Thus, it cannot be predicted or generalized until the experiments are conducted using various metal-zeolite complexes. It is not difficult to predict the outcome of the synthesis based on the initial observation from the catalysts characterization studies. Based on the results from the initial stages of research, students are advised to make a reasoned decision about the choice of solvents, metals, or any other reaction conditions to predict an outcome of the experiments. Students are also advised to be patient and vigilant of any unexpected results or observations. New observations may lead to a new question and even an entirely new approach to the experiments. If the experimental results fail to support the hypothesis, redesigning the experiments might be helpful in addressing the initial question. Through this process, students can learn that temperance and iteration are an essential part of scientific discovery.

Using CURE Data

Student's data are saved in the form of written reports, Powerpoint presentations, and posters. Students present their research findings at the Annual Research Symposium held at Alabama State University every year. Students may apply for a registration waiver and travel award to present at the ABRCMS conference. A potential publication is anticipated to report the synthesis, characterization, and biomass conversion of the metal impregnated zeolite catalysts to produce liquid fuel platform chemicals.

Resources

Birmingham, W. R., A. Toftgaard Pedersen, M. Dias Gomes, M. Bøje Madsen, M. Breuer, J. M. Woodley and N. J. Turner (2021). "Toward scalable biocatalytic conversion of 5-hydroxymethylfurfural by galactose oxidase using coordinated reaction and enzyme engineering." Nature Communications 12(1): 4946.

Sarda, K. K., A. Bhandari, K. K. Pant and S. Jain (2012). "Deep desulfurization of diesel fuel by selective adsorption over Ni/Al2O3 and Ni/ZSM-5 extrudates." Fuel 93: 86-91.

Takkellapati, S., T. Li and M. A. Gonzalez (2018). "An Overview of Biorefinery Derived Platform Chemicals from a Cellulose and Hemicellulose Biorefinery." Clean technologies and environmental policy 20(7): 1615-1630.