The place for Green Chemistry in industrial engineering education
Stefanus Muryanto
Office of Research and Department of Chemical Engineering,
UNTAG University in Semarang
Jalan Pawiyatan Luhur, Bendan Duwur, Semarang, INDONESIA 50233
E-mail: stefanus_muryanto665@yahoo.com
Abstract Green Chemistry is the application of a set of principles that aims to minimize the negative impact of chemical processes and products on human health and environment. It therefore, lends support to the promotion of the philosophy and practice of sustainable development. In this era of “global warming”, the expectation of all sections of society that engineers demonstrate their commitment to sustainable development is increasingly high.Conversely,such an expectation can be seen as an excellent opportunity for the engineering profession to show how vital its role is in curbing the global warming and its associated risks. This paper presents an approach to integrate Green Chemistry into industrial engineering curriculum as one possible way to address the issue of education for sustainable development. The twelve principles of Green Chemistry were selectively inserted into chemistry courses which were taught in semester one and two respectively. These principles were conveyed in line with the existing lecture material of General Chemistry through worked examples, in-class discussions, and homework. It was carefully planned so that the insertion of Green Chemistry topics did not interrupt the core lecture items or place extra burden for the students. Tentative findings of the present work show that the integration approach could help stimulate students’ interest in chemistry, the subject which is generally looked upon as highly demanding. Additionally, it was felt that students’ awareness and sensitivity to societal issues related to sustainable development were enhanced.
Keywords: chemistry teaching, engineering curriculum, Green Chemistry, industrial engineering education, sustainable development.
Introduction
Green Chemistry is the application of a set of principles that aims to minimize the negative impact of chemical processes and products on human health and environment. Simply stated, it is the use of chemistry for pollution prevention in the first place [1]. Green Chemistry is not a new branch of chemistry but a new way of thinking about how to utilize the knowledge of chemistry to reduce or eliminate the generation of hazardous substances in the design, production and application of chemical products [2, 3]. The term “green” implies environment-friendly and sustainable characteristics. Green Chemistry can involve any branch of chemistry: organic, inorganic, analytical, physical, biochemistry and so on. In addition, Green Chemistry actually covers all disciplines that interface with chemistry. In reality, the definition is continuously changing as more and more refined methods for the prevention and elimination of waste are developed [4]. The most advantageous principles of it that are held today may be replaced in the future consistent with the development of the methods. As articulated by Paul Anastas and John Warner [5], Green Chemistry consists of 12 principles (see Appendix) with the underlying concept to solve pollution problems by preventing the generation of waste in the first instance. The concept is prevention and reduction of waste in all its forms [6], thus negating post-processing of wastes [4]. The worsening environmental conditions which are mostly attributable to human activities (ozone layer depletion, global warming, climate change, polluted lands and waters etc.) necessitate urgent actions. Green Chemistry, which by its nature emphasizes waste prevention and elimination in the first place, is a valuable tool for such actions. To save the earth from further destruction, one important way is to instill the attitudes of humankind with values consistent with a sustainable life style through education [7]. This paper discusses an ongoing activity to integrate the principles of Green Chemistry into undergraduate industrial engineering curriculum, through general chemistry course taught by the author. Realizing that Green Chemistry has the potential to solve many environmental problems, the need for such integration has become increasingly important and the integration has been carried out in many higher education institutions around the globe [1, 2, 4, 7, 8, 9, 10, 11, 12]. The activity proposed in this paper is in line with and in support to the aforementioned practice.
Chemistry Course for Industrial Engineering Curriculum
The general chemistry course for first year industrial engineering students is a two-semester class designed to provide a basic knowledge of chemistry so that students appreciate various chemistry-based industrial situations. The general chemistry course is a logical place to insert concepts of Green Chemistry since after this course, there is no specific chemistry-related subject given. In the industrial engineering curriculum, the chemistry-related course, as far as the author perceives, might be seen as mere “add-on”, the emphasis of which is that students become chemically informed scientists, (and not necessarily become chemists). The level of the chemistry course is introductory, and the content is similar (in some cases it is a repetition) to those given during high schools. The course is not popular among the students. In fact, they have a rather negative view of it – the course is seen as hard and highly demanding. The author argues that the general chemistry class may continue to be a mere add-on subject, unless it considers topics pertinent to real industry situations. Therefore, integrating the principles of Green Chemistry into industrial engineering curriculum can serve two purposes. Firstly, to introduce students to the most recent chemistry topics related to sustainable development issues. Secondly, to teach students topics related to solving problems in real world cases of industry with the intention that they may begin to appreciate the course. At the institution where the author of this paper teaches, the textbook used for the course is the sixth edition of General College Chemistry by Keenan, Kleinfelter and Wood [13], which has been translated into Indonesian [14]. In order to keep abreast of the chemical topics being taught at other universities, the author of this paper relies on on-line sources, such as those provided by Cann [11] and Balko [15].
Green Chemistry Topics for Industrial Engineering Curriculum
The General College Chemistry textbook which has been translated into Indonesian as discussed previously, comes in two volumes. Volume 1 consists of 16 chapters, of which Chapter 1 provides an excellent entry point for the introduction of Green Chemistry. There is in Chapter 1, a subheading titled: Chemistry and Our Way of Life, which relates closely to the way we manage our world and our environment.
“Chemists play an important role in looking for new methods to treat waste so that the waste will not be too detrimental”
[own translation – Chapter 1[14:4].
Perusing the two volumes of the General College Chemistry, the author of this paper identifies many topics which can be good avenues for the introduction of Green Chemistry principles. For example, a particular topic in Chapter 1 reads: Overview of Descriptive and Theoetical Chemistry. This topic discusses the important role of chemistry and how human life and civilization has been influenced by the development in chemistry. The authors of the textbook specifically elaborate the contribution of the knowledge of chemistry to the development in medical and agriculture as well as its impact on the explosion of human population, which eventually leads to environmental degradation and ecological disaster. The connection to Green Chemistry is then obvious: understanding basic chemistry and how human civilization has been influenced by the development in chemistry lays the groundwork for applying the Green Chemistry principles of preventing waste, designing safer chemicals and products, designing less hazardous chemical syntheses, designing for degradation after use, and adopting inherently safer chemistry for accident prevention, respectively. Another example is found in Chapter 2, i.e. in the topics which elaborate chemical equations and stoichiometry. Understanding these two topics lays the foundation for applying Green principles of preventing waste, maximizing atom economy and using catalysts instead of stoichiometric reagents (principles 1, 2 and 9 respectively). Some topics in the textbook are easily related to the Green Chemistry principles. These include aluminum recycling in Chapter 21, and the Special Topic: Economy of Metanol-based Fuel in Chapter 26. Some other topics, however, such as Chemical Kinetics in Chapter 14 may well be related to the Green Chemistry principles of avoiding unnecessary chemical derivatives (principle no 8), but would require a great deal of explanation. The author of this paper prefers not to insert the Green Chemistry concepts into this chapter. It should be noted that not all chapters from the two volumes of the textbook is given throughout the two-semester course, since chemistry is non-major in the industrial engineering curriculum, and that the curriculum is already crowded. In the following section, two examples taken from the Indonesian version of General College Chemistry [14] are presented and discussed in the light of Green Chemistry.
Green Chemistry Problem 1
Theoretical versus True Yields
The discussion on theoretical versus true yields can be connected to several Green principles of preventing waste, using catalysts and not stoichiometric reagents, avoiding chemical derivatives, and maximizing atom economy, respectively. The theoretical yield is defined as the quantities of the product of a reaction assuming that the reaction goes to completion. It is the quantity of yield based on theoretical calculation. In reality, a chemical reaction never proceeds in such a manner that the reactants are fully consumed. This is due to several factors depending on the characteristics of the reaction, such as incomplete mixing [16]. Instead, true yield is obtained which is different from (and always less than) the one theoretically calculated.
Problem Statement
(Taken from Example 2.8 in ref. 14 pp 56-57)
A certain type of coal contains 1.7 percent sulphur. Suppose the burning reaction of the sulphur can be written as follows:
S + O2 SO2
How much air-polluted compound of gaseous SO2 is released to the air from burning one metric tonne of coal, if the efficiency of the reaction is 79 percent?
Problem Solution
The quantity of sulphur in mol per metric tonne of coal can be calculated as follows:
The weight of sulphur:
= 530 mol of S.
The sulphur content of the coal is thus 530 mol. According to the chemical equation above, 530 mol of S will be burned to yield 530 mol of SO2. Since the reaction efficiency is only 79 %, hence the mol of SO2 yielded is
or 27 kg.
The author of this paper has tried to link this with the maximum burning of coal; which in such a case all of the one metric tonne of coal is burned. In our example above, (100 – 79) % of the coal, which equals 210 kg is not burned and thus wasted. Consequently, in terms of atom economy this situation is not preferable, since principle 2 of the Green Chemistry is violated. A more efficient way to burn the coal is governed by the following conditions: ample supply of air, and intimate contact between the coal and the air. Of course these two engineering aspects of combustion are beyond the scope of general chemistry, but as an extra in-class discussion they can be useful information since the students will become engineers at the end of their study. The problem of sulphur burning can also be extended into a class discussion of a major environmental problem, namely the formation of acid rain through the reaction of gaseous SO2 with rain water.
Green Chemistry Problem 2
Limiting versus Excess Reagents
In most chemical reactions, it cannot be expected that the quantities of reactants required are available stoichiometrically, i.e. in the exact proportions as demanded by the reaction equation. Some of the reacting compounds are present in excess of the amount theoretically required for combination with the others. However, the quantities of the products that will be obtained are determined by the limiting reactants, i.e. the compounds which are not present in excess. Discussion about limiting versus excess reagents lends itself to the Green Chemistry principles of preventing waste, maximizing atom economy and the use of catalysts, respectively.
Problem Statement
(Taken from Example 2.9 in ref. 14 pp 58-59)
Gold is essentially chemically unreactive. However, hot chlorine gas can be sufficiently reactive that at 1500C gold reacts with the gaseous chlorine according to the following reaction:
2 Au + 3 Cl2 2 AuCl3
Suppose 10.0 g of gold and 10.0 g Cl2 are placed in a closed container and heated until a complete reaction takes place. Which reagent is the limiting one? What is the quantity of the unreacted component or the excess reagent left?
Problem Solution
The stoichiometric ratio for the reaction:
.
Whereas the available ratio for the reaction:
.
The above calculation shows that 0.67 mol Au is required to react with 1.0 mol Cl2. However, the available Au is only 0.30 mol per 1.0 mol Cl2. Therefore, Au is the limiting reagent. All Au will react and there will be an excess of Cl2. Hence, the quantities of AuCl3 formed = 0.0508 mol. (Students should verify this for themselves!).
Hence, the quantity of Cl2 reacted:
Thus, the excess reagent is Cl2 and it amounts to 10.0 g – 5.4 g = 4.6 g.
The above example can be connected to the Green Chemistry principles of using catalysts to promote a reaction (principle 9). By using catalysts a more efficient reaction can be carried out. Catalysts can be used repeatedly until inactive, at which time they need to be reactivated, for example by heat treatment. A further link to Green Chemistry principles could be provided, for example by referring to principle 6: Design for energy efficiency. The principle states that whenever possible, chemical reactions should be conducted at ambient temperature and pressure. For homework and self-directed learning, it is useful for the students to check the MSDS (= materials safety data sheets) for chlorine, which can be viewed online at
Student Feedback
Student feed back via questionnaire was obtained twice, i.e. at the beginning and near the end of the lectures. Overall, students are most positive about Green Chemistry. They stated that the Green Chemistry principles are directly relevant to industry. In addition, they also pointed out that all parties: academics at all levels, industry and the general public should be made aware of the Green Chemistry concepts which can be a valuable tool to deal with environment and sustainable development. Informal feedback indicating acceptance of Green Chemistry concepts was also obtained from students whom the author knows outside of class hours. They pointed out that the Green Chemistry concepts could improve their awareness of the role of chemistry in alleviating the burden on the environment, and could indirectly enhance their interest in chemistry. Most of the students admitted that their understanding about chemistry is still below that required for the environmental protection. The Green Chemistry principles, they stated, were something new to them although on several occasions (mostly during previous pre-university studies) they had been taught topics similar to Green Chemistry. The students are now aware that there is a chemistry philosophy and practice suitable for environmental protection.
Concluding Remarks
The activity of integrating Green Chemistry into the undergraduate industrial engineering curriculum through introductory level chemistry class as reported in this paper indicates that Green Chemistry principles can be well placed within the curriculum. It was found that the integration could be carried out easily without interfering with the core parts of the chemistry subject. Moreover, the integration could enhance students’ interests in chemistry as well as their awareness of environmental issues.
Acknowledgements
The author is indebted to Yuli Rahmawati, a PhD candidate currently working on Green Chemistry education at Curtin University of Technology, Australia, for providing some references. Also, the acceptance of this paper by the ISSTEC 2009 is gratefully acknowledged.
References
1. Hjeresen, D. et al. 2000. Green Chemistry and Education. J. Chem. Education, v.77, n. 12: 1543-1547.
2. Cue, B. 2007. , in: Anastas et al. (Eds.), Exploring Opportunities in Green Chemistry and Engineering Education: A Workshop Summary to the Chemical Sciences Roundtable, National Academies Press, Washington.
3. Hazel, B. 2002. EHSC Note on GREEN CHEMISTRY. Royal Society of Chemistry, London. (www.rsc.org, viewed on 28 Nov.2008).
4. Gron, L.U. 2008. Sustaining the green revolution through education. Suppl. to Chimica Oggi/CHEMISTRY TODAY, v. 25, n. 6: 11-13.
5. Anastas, P. T. and Warner, J. C. 1998. Green Chemistry Theory and Practice, Oxford University Press, New York.
6. Clark, J.H. et al. 2005. Green Chemistry for Sustainable Development, in: Alfonso, C.A.M and Crespo, J.G. (Eds.) Green Separation Processes, Wiley-VCH Weinheim, Germany.
7. Karpudewan, M. et al. 2007. Preparing Pre-service Chemistry Teachers for EfSD through Green Chemistry, Proceedings of 11th UNESCO-APEID Int. Conf. Reinventing Higher Education: Toward Participatory and Sustainable Development, 12-14 Dec., Bangkok.
8. Raston, C.L. and Scott, J.L. 2001. Teaching green chemistry. Third-year-level module and beyond. Pure Appl. Chem., v.73, n. 8: 1257-1260.
9. Anastas, P.T. et al. (Eds.) 2007. Exploring Opportunities in Green Chemistry and Engineering Education: A Workshop Summary to the Chemical Sciences Roundtable, National Academies Press, Washington.
10. Liu, K-T. 2005. Implantation of the principles of Green Chemistry in the Teaching of Sophomore Organic Chemistry, 229th ACS National Meetings, Abstr. No. CHED 1334, San Diego, Calif., USA.
11. Cann, M.C. 2006. Syllabus: CHEM. 100 Elements of Chemistry, Univ. Scranton, online:http://academic.scranton.edu/faculty/CANNM1/ch100sy1.doc(12 Nov.2008).
12. Rahmawati, Y. 2008. Green Chemistry in Analytical Chemistry Laboratory: The Reflections on my Teaching (personal communication).
13. Keenan, C.W. et al. 1980. General College Chemistry, 6th ed., Harper and Row, New York.
14. Pudjaatmaka, A.H. 1992. Kimia Untuk Universitas, edisi ke-6, v. 1, Erlangga Publishing, Jakarta.
15. Balko, B. 2007. General Chemistry I, Chemistry 110, Section 01 www.lclark.edu/~balko/chem110, (12 August 2008).
16. Marlin, T.E. 2000. Process Control:Designing Processes and Control Systems for Dynamic Performance, 2nd international edition, McGraw-Hill, Boston etc.
Appendix. The Twelve Green Chemistry principles as proposed by Anastas and Warner [5]
1 Prevention It is better to prevent waste than to treat or clean up waste after it has been generated.
2 Atom economy Synthetic methods should be designed to maximize the incorporation of all materials used in the process into the final products.
3 Less hazardous chemical syntheses Wherever practicable, synthetic methods should be designed to use and generate substances that possess little or no toxicity to people or the environment.
4 Design for safer chemicals Chemical products should be designed to affect their desired function while minimizing their toxicity.
5 Safer solvents and auxiliaries The use of auxiliary substances (e.g. solvents or separation agents) should be made unnecessary whenever possible and innocuous when used.
6 Design for energy efficiency Energy requirements of chemical processes should be recognized for their environment and economic impacts and should be minimized. If possible, synthetic methods should be conducted at ambient temperature and pressure.
7 Use of renewable feedstock A raw material or feedstock should be renewable rather than depleting whenever technically and economically practicable.
8 Reduce derivatives Unnecessary derivatization (use of blocking groups, protection/deprotection, and temporary modification of physical/chemical processes) should be minimized or avoided if possible, because such steps require additional reagents and can generate waste.
9 Catalysis Catalytic reagents (as selective as possible) are superior to stoichiometric reagents.
10 Design for degradation Chemical products should be designed so that at the end of their function they break down into innocuous degradation products and do not persist in the environment.
11 Real-time analysis for pollution prevention Analytical methodologies need to be further developed to allow for real-time, in-process monitoring and control prior to the formation of hazardous substances.
12 Inherently safer chemistry for accident prevention Substances and the form of a substance used in a chemical process should be chosen to minimize the potential for chemical accidents, including releases, explosions, and fires.
No comments:
Post a Comment