Phosphate Recovery as a Topic for Practical and ... - ACS Publications

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Cite This: J. Chem. Educ. XXXX, XXX, XXX−XXX

Phosphate Recovery as a Topic for Practical and Interdisciplinary Chemistry Learning Christian Zowada,*,† Antje Siol,*,† Ozcan Gulacar,*,‡ and Ingo Eilks*,† †

Department of Biology and Chemistry, Institute for Science Education, University of Bremen, 28334 Bremen, Germany Department of Chemistry, University of CaliforniaDavis, One Shields Avenue, Davis, California 95616, United States

J. Chem. Educ. Downloaded from pubs.acs.org by VOLUNTEER STATE COMMUNITY COLG on 04/19/19. For personal use only.

‡

S Supporting Information *

ABSTRACT: Phosphates are essential components of any efficient fertilizer. Natural phosphate rock is, however, not available in every part of the world. According to the European Commission, phosphate rock has high economic importance as well as a certain supply riskat least for Europe. For these reasons, environmental technology research has received a great attention from the stakeholders that provided support in developing processes for recovering phosphate from wastewater and sewage sludge to help to close the phosphate cycle and reduce potential risks, including eutrophication and its influence on the environment. In this paper, we present a design case study of integrating the idea of phosphate recovery into chemistry education via a nonformal learning experience for high school students in Germany. The paper discusses a series of experiments and shows how they were embedded through interdisciplinary curriculum development.

KEYWORDS: High School/Introductory Chemistry, Interdisciplinary/Multidisciplinary, Curriculum, Hands-On Learning/Manipulatives, Multimedia-Based Learning, Applications of Chemistry

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INTRODUCTION The global society faces several key challenges such as poverty, hunger, climate change, and ocean acidification. These challenges cannot be solved without an increase of knowledge in and about chemistry.1 Since these challenges need to be approached in an interdisciplinary way, the chemistry curriculum should go beyond “pure chemical” content and also incorporate interdisciplinary learning to reflect chemistry’s impact on society, the environment, and the economy.2 These are often neglected perspectives in chemistry education.3 One way to deal with the global challenges in education is teaching socioscientific issues4 with relation to the sustainability debate.5 This approach has the potential to help learners become scientifically literate and responsible citizens.6 Some of the global socioscientific challenges that relate to the sustainability debate include meeting the needs for clean water, food, improved health, and enhanced energy security. All of these challenges are being addressed as parts of the Sustainable Development Goals (SDGs) defined by the United Nations.7 Among the SDGs, fighting against hunger and protecting the world’s water and land resources are especially important to protect the well-being of humankind. For these goals, phosphate is a central substance. On one side, phosphates are needed as fertilizers to provide the world with enough food. On the other side, too much phosphate in the environment can cause eutrophication. The problem of too much phosphate in the environment is also identified within the concept of the planetary boundaries. The intense use of the element © XXXX American Chemical Society and Division of Chemical Education, Inc.

phosphorus in the form of phosphates in agriculture has been already described as one of the most demanding challenges for a sustainable development of the world.8 A solution for both challenges would be the recovery of phosphate from wastewater and sewage sludge to recycle it in the production of new fertilizers. This paper discusses the integration of phosphate recovery as an example of applied environmental technology into chemistry education via a nonformal learning experience for high school students in Germany. Along with a short overview on phosphate in chemistry education literature, a description of the intervention, the details of the experiments, and their introductions via an interdisciplinary teaching approach are explained here.

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TEACHING CHEMISTRY ON PHOSPHATES The time which is spent on phosphate and the element phosphorus is generally not high in most high school or undergraduate chemistry curricula. Nevertheless, there have been suggestions for teaching about phosphates, such as detecting and quantifying phosphate in cola,9 investigating the competitive sorption of oxalate and phosphate in soil using chromatography,10 using ion-exchange resins for measuring Special Issue: Reimagining Chemistry Education: Systems Thinking, and Green and Sustainable Chemistry Received: December 5, 2018 Revised: March 26, 2019

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DOI: 10.1021/acs.jchemed.8b01000 J. Chem. Educ. XXXX, XXX, XXX−XXX

Journal of Chemical Education

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phosphate,11 and detailing its former use in detergents.12 An important field when it comes to the chemistry of phosphates concerns environmental issues in connection with analyzing water samples from lakes or rivers. The measurement of phosphate (and nitrate) is an important step to get information on water quality. Service learning projects are suggested, monitoring the environment to inform the public on the status of water resources in nature.13,14 Schwarz, Frenzel, Richter, Täuscher, and Kubsch15 described field trip learning focusing analytical and environmental chemistry where participants analyzed water samples from different lakes to learn about limnology. Most ideas for teaching about phosphate in the literature are connected to the thread of eutrophication caused by the overly intense use of fertilizers. Too many nutrients (especially nitrogen and phosphorus fertilizers) in the environment can cause extensive algae growth. This is one reason a sustainable use of fertilizers is needed. This issue is suggested also in the concept of planetary boundaries.8 Limiting biogeochemical flows of nitrogen (nitrate) and phosphorus (phosphate) into the environment are suggested as one of the key challenges of our time. Suitable teaching approaches for issues such as limiting biogeochemical flows and associated risks, e.g. eutrophication, are suggested to go beyond pure content knowledge learning. It is suggested to operate a more holistic approach in order to include broader views on sustainable life style and development.5 The connections between the sustainability debate, chemistry education and socioscientific issues has long been made.16 Juntunen and Aksela17 or Koutalidi, Psallidas, and Scoullos18 explicitly suggested topics such as eutrophication or biogeochemical flows as suitable for chemistry teaching. Generally, the idea is that there is too much phosphate from fertilizers ending up in the environment (e.g., in lakes or oceans) and limiting its use or recycling is suggested. Other perspectives on phosphate are much less present. One such perspective is to consider phosphate as a resource which might run out or can become subject to a supply risk for certain countries because of its unequal distribution in the world, as suggested by the European Commission. 19 Koutalidi and Scoullos20 have already suggested phosphate rock scarcity as a potential topic in chemistry education. They, however, did not suggest any practical work on the topic. In this paper, we take up the corresponding discussions of phosphate as a crucial raw material and a thread for the environment. On the basis of current developments in applied environmental technology, we suggest a set of experiments for the high school and undergraduate levels focusing phosphate recovery from wastewater, following the suggestion of Mayer and colleagues21 to introduce the topic of phosphate recovery to a broad audience and to education. We describe how these experiments can be embedded in an interdisciplinary learning approach supported by a digital learning environment, including perspectives from, for example, biology, geography, and the economy.

crop growth, and any decrease in its amount will directly influence the global crop yields. It is not possible to substitute phosphate in fertilizers. Also, as of today, there is hardly any recycling of phosphates carried out in large amounts. Regarding the supply risk the European Commission wrote: “There is a high supply risk due to concentrated production from three main countries, though it is close to the supply risk threshold. Corporate concentration for this material appears relatively high compared to other materials, rising over the past five years. The economic importance is moderately high, exceeding the criticality threshold. There is no recycled input and substitution is impossible in its main application as an input to fertilizers and other chemicals.”22 (p 16). The three main countries mentioned by the European Commission are Morocco (including the area of former Western Sahara), China, and the USA.24 Morocco has about 75% of the worldś known phosphate reserves, partially in the former Western Sahara region. Additionally, it should be noted that there is currently an unresolved political conflict about the legal status of the Western Sahara region.25 Only four countries are using about 70% of the world’s phosphate fertilizer: China, India, USA, and Brazil, whereby Africa with its fast-growing population has a consumption of only about 2.5%.26 As the demand increases, an important question arises on the time that the natural phosphate reserves will expire. The current estimation of the phosphate range is about 300 years.26 Nevertheless, there are good reasons even today for closing the phosphate cycle. Phosphate recovery will help to protect the environment from growing amounts of excess phosphate.26−28 Phosphate recovery will also help to limit the growing release of heavy metals from natural phosphate rock to the environment, such as cadmium and uranium. Closing the phosphate cycle through recycling also seems to be a promising solution for reducing the potential supply risk for certain countries. In wastewater treatment plants, tons of sewage sludge accumulate daily. In Germany, a treatment plant designed for a town of one million people produces approximately 150 tons of sewage sludge per day. In the last few years, different efforts have been made to recycle phosphate out of sewage sludge or sewage sludge ash. New technical solutions are under development. Basically, they all operate by the same five steps: • leaching: release of the phosphate from the matrix by pH reduction to 9 • filtration: separation of the fallout from the dissolved residue • product treatment As an example, the ExtraPhos process from the Chemische Fabrik Budenheim KG29 in Germany will be presented here briefly. The starting product is sewage sludge, from which the phosphate is partially mobilized by adding carbon dioxide in a closed cycle (a pressure of about 10 bar causes a decrease in pH to around 4.5−5.5). Subsequently, the solid phase is separated from the aqueous phase. Phosphate is precipitated in the form of calcium phosphate by adding lime milk. The aim of the process is to achieve a recovery rate of 50%. The calcium phosphate can actually be used as a fertilizer without further processing. Among other usages, the low-phosphate sewage

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IMPORTANCE OF PHOSPHATE RECOVERY First, in 2014 and, again, in 2017, the European Commission identified phosphate rock as a critical raw material,19,22 at least for Europe. Critical raw materials are characterized by high economic importance with a simultaneous supply risk. The high economic importance arises from the growing demand for fertilizers.23 Phosphate is a limiting nutrient in B



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because working with real sewage sludge has a high risk of contamination. Every recovery experiment is based on four steps inspired by the real processes: • leaching: resolve the phosphate out of the sewage sludge/sewage sludge ash • filtration: separating the solution from solid sewage sludge • crystallization and filtration: crystallizing the phosphates by a precipitant • quantification: measuring the chemical yield using a colorimetric test Here, in order to highlight the procedure, the experiment on ExtraPhos will be described in detail. During the leaching, the pH is lowered to 4.5−5.5 by pressing carbon dioxide into the solution using a conventional soda stream. The phosphate is dissolved out of the model sewage sludge. The solution is filtered. Once a clear solution is obtained, lime milk is added to start the precipitation. To increase the pH, sodium hydroxide is added. The pH value has to be raised above 9. The calcium phosphate precipitates and is separated by filtration. To calculate the recovery rate, a colorimetric measurement is used. For this measurement, MColortest is used (Figure 1). In more advanced groups, photometry or titrations can be used. Through measurement of the remaining content of phosphate in the filtrate, the recovery rate can be determined.

sludge can also be reused in the cement industry. An inital pilot plant has been in operation since June 2017.29

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HAZARDS The experiments in the following section are generally safe. However, it should be noted that sulfuric acid, sodium hydroxide solution, limewater, and acidic ammonium molybdate solution are corrosive. Detailed information on hazards of the chemicals used are given in the Supporting Information.

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PHOSPHATE RECOVERY IN CHEMISTRY EDUCATION Matlin et al.1 point out that “education and practice in chemistry must be re-oriented so that it inculcates skills in inter-disciplinary and trans-disciplinary approaches informed by systems thinking and by concerns for the principles of sustainability and responsibility” (p 942). In line with this suggestion, chemistry educators need to discuss how to reflect current issues such as the man-made age, the Anthropocene, in the chemistry curriculum,30 especially at times like ours in which planetary boundaries are crossed.8 Many topics such as the global phosphorus flow have a high degree of complexity so that ”none of them can be understood or addressed without taking into account the whole ensemble”31 (p 1860). In order to gain a more holistic approach and foster systems thinking, teaching must go beyond disciplinary boundaries and provide a platform and a mechanism to link seemingly unrelated facts as well as include topics concerning the sustainability debate.32 In Earth System Education, systems thinking is prominent. Ben-Zvi Assaraf and Orion suggest an evaluation of characteristics of systems thinking starting with the identification of individual components leading up to an investigation of interconnectedness between those components, so that cyclicity in systems and their potential to provide solutions about today’s complex issues can be better understood (see also ref 34). In Germany, Rempfler and Uphues35 suggested a model for systems competence in geography education that includes systems organization, systems behavior, and systems-adequate intentions, which altogether should guide those who design the curriculum. The dimensions start with the ability to identify a few elements and relations of a system (mainly isolated), study them individually, and understand the relationship between them. Such an approach should elevate students to a higher stage where they can begin to develop well-founded plans to deal with complex issues. A geographical systems perspective was already adopted to enrich chemistry teaching by allowing more holistic views toward major challenges such as phosphate sustainability that the global community faces.36 Phosphate rock is such a topic where more holistic views are relevant due to the topic’s relatedness to many fields such as chemistry as it deals with recycling processes, biology or agriculture that influence the world’s food supply, or geographical and political issues in the use and locations of the world’s phosphate reserves. In this paper, an approach is suggested to adapt recycling processes of phosphate for high school and college classes. A series of experiments was developed following innovative procedures from environmental technology. Four basic technical procedures were chosen that deal with a model sewage sludge (or model sludge ash) that contained water, paper pulp (3% by weight), and a certain amount of phosphate (c = 1000 mg/L phosphate). Model sewage sludge is recommended in the experiments

Figure 1. MColorTest for measuring phosphate concentrations in solution.

Table 1 provides an overview of all four adapted processes. Detailed descriptions of the experiments can be found in the Supporting Information to this article.

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MAKING THE PRACTICAL WORK AN INTERDISCIPLINARY CURRICULUM EXPERIENCE In order to carry out the experiments with high school students, the adapted recovery processes were embedded in a nonformal learning laboratory. The laboratory is regularly visited by secondary school students in groups. The laboratory visits are integrated into regular school chemistry teaching and generally last half a day. The laboratory is located at a midsize public research university in northern Germany. Traveling to the university may not be necessary if the school has all the equipment and the infrastructure to run the experiments successfully. It is possible to perform the experiments in schools, as the use of chemicals and tools does not require any special training and these chemicals and tools are not specific for university use. C



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feedback was collected and influenced the cyclical design approach. The digital learning environment (PREZI) is suggested as an informing platform to be used before and after the laboratory experience. The suggested learning activity has three parts: preparation, laboratory work, and follow-up. In order to become familiar with the context of the laboratory in advance, students were asked to explore the PREZI learning environment, which provides information on the nature of phosphates and their biological and agricultural importance. It also explains the use of phosphates in daily life and the economic, societal, and geographical dimensions of the topic. The societal and geographical dimensions are suggested to connect the laboratory experience to issues of a growing world population, the need for fertilizers, and the importance of phosphate recovery for sustainability. The learning environment also informs the learners about the importance of phosphates for all of the countries around the world by highlighting the cases of Morocco and the island of Nauru. Nauru used to be one of the richest countries in the world due to phosphate exploitation but became impoverished very quickly after the phosphate resources ran out. Today, Morocco is the biggest phosphate provider in the world, owning about 75% of the world’s reserves. This approach should provide the learners with a rich context and help them construct meaningful learning experiences in the laboratory with practical and interdisciplinary information. The central part of the learning activity is comprised of laboratory experiments. The set of experiments can be individually adopted on the basis of the needs of student groups. The experiments vary in their complexity: e.g. simple experiments dealing with plant growth or analyzing probes for phosphate in semiquantitative and quantitative measures. A model for differentiated learning environments in nonformal education was used.48,49 The experiments are designed to be operated by guided inquiry learning. According to the differentiation model, graded learning aids on the content and laboratory procedure are provided in case students need more structure.48 In a second set of experiments, the adapted recycling technologies are performed by the students using the same design. The adapted recycling processes are not open due to their orientation toward real industrial practice. Thus, they

Table 1. Overview of Adapted Processes process name ExtraPhosa Stuttgarter Verfahrenb Ostara’s Pearl and WASSTRIP Processc d

TetraPhos

acid used to decrease pH

base used to increase pH

CO2 (g)

NaOH, 1 mol/L H2SO4, NaOH, 1 0.5 mol/L mol/L H2SO4, 0.5 mol/L

H2SO4, 0.5 mol/L

NaOH, 1 mol/L

NaOH, 1 mol/L

precipitant Ca(OH)2 sat. MgCl2e NH4Clf MgCl2e NH4Clf Ca(OH)2 sat.

product Ca3(PO4)2 MAP (struvite) MAP (struvite)

Ca3(PO4)2

a

See ref 29. bSee ref 37. cSee ref 38. dSee ref 39. ec = 2.6 g/0.1 L. fc = 2.5 g/0.1 L.

A teaching approach was designed using participatory action research.40 Action research has the potential to solve problems in real-life situations through an iterative and collaborative process of planning, acting, evaluating, and reflecting. Action research aims to minimize the negative effects of traditional teaching practices while maximizing positive outcomes involving students in the learning process.41 According to Laudonia, Mamlok-Naaman, Abels, and Eilks,42 action research focuses on improving the curriculum and pedagogy while enhancing students’ cognitive gains and teachers’ professional development. This project suggests new ideas that enrich the curriculum and provide an authentic learning experience by completing a set of carefully developed experiments. It was operated according to the model suggested by Eilks and Ralle33 that proved to be successful in developing chemistry lesson plans on the basis of evidence. 43−45 Also, Hodson46 recommends action research as a suitable way to develop changes in the curriculum as well as of contributing to teachers’ continuing professional development. The action research process in this case took three rounds, where the researchers got feedback from experienced teachers47 and discussed experiments as well as how to design the context. A digital learning environment (PREZI) and experimental instructions were developed. In trials, oral and written student

Figure 2. Selected items from students’ perceptions of the digital learning environment and laboratory (n = 47). D



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are based on the principles of structured inquiry learning. Detailed descriptions on how the experiments are to be conducted can be found in the Supporting Information in a cook-book recipe format. Upon the completion of the laboratory work, the students were asked to share their experiences and calculated recovery yields so that the best process could be identified on the basis of the students’ actual data. Typical yields appeared to be between 50% and 80%, which are considered relatively high and are within the acceptable range. Back in school, it is recommended that teachers spend time and help their students understand the relationship between the procedures followed during the experiments and the big picture related to phosphate sustainability. Going through the digital learning environment should help the students strengthen their appreciation of the need for phosphate recovery and see the interactions between different dimensions of the topic better, from economic to geographic and from societal to environmental.

(4) Describe the aspects which you liked in the PREZI. (5) Describe the aspects which we might improve about the PREZI. The students’ responses were analyzed by two coders using a summarizing qualitative content analysis (QCA) according to Mayring50 (Cohens κ = 0.925). QCA is suggested for examining qualitative data in a cyclical and multistep procedure. The responses obtained from all the participants were first paraphrased in order to determine the relevant content. Then, the data were analyzed to identify common themes and categories inductively. Two rounds of coding were considered to be sufficient to reveal the patterns, which describe the data. About the laboratory, most students wrote that they liked the structure of the experiments (“That the experiments were well structured, f un and also educational.”) and being able to work within the small groups independently. To enhance the students’ learning experience, some of them suggested that the instructions for the experiments include more details and explain the procedure better. As for the digital learning environment, most students liked the design and the content, which were concise and informative. One additional question was asked in the questionnaire explicitly to determine the most important aspects of the topic they have learned by utilizing the learning environment and performing the experiments. Here, most students spotted that they developed a better understanding about the role of phosphate in the world, advanced their experimental skills, and learned some special techniques such as measuring phosphate content (“I have learned to conduct experiment on my own and with selfresponsibility, [···] I have learned that phosphorus is one of the most important resources for mankind [···] and that there is a sort of scarcity. I have also learned about the recovery of phosphorus. Generally, I gained knowledge about phosphorus.”). Table 2 shows an example of the categories from question 4: describe the aspects which you liked about the PREZI.

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FIRST EXPERIENCES The digital learning environment and experiments were tested with preservice chemistry teachers (BSc level) and one high school class in January 2018. After each testing, the materials were modified to consider the feedback of experienced teachers, who formed an action research group. The updated materials were then tried out by three groups of high school students (age 15−16). The students worked with the digital learning environment for 90 min before visiting the laboratory. The laboratory work took about 3 h. The students were given a perception questionnaire after the laboratory visit containing several four-point Likert scale items and five open questions. The feedback questionnaire was administered between February and April in 2018, and 47 students voluntarily provided feedback. A summary of selected student feedback from the Likert questions is provided in Figure 2. Overall most students felt that they learned a great deal about phosphates (78% agreed or agreed mostly). About threefourths of the students indicated that they liked the provided instructions and enjoyed working with their peers on the experiments by selecting “agreed” and “agreed mostly” options. Eighty-four percent disagreed or disagreed partially that they had some issues while doing the experiments. The digital learning environment was perceived very positively, and the students enjoyed learning through it (75% agreed or agreed mostly). They did not report any observed difficulties while using it (94% agreed partially or disagreed). Furthermore, 84% agreed or agreed mostly that the digital learning environment and the experiments complement each other well. However, only about one-third of the students stated that they are interested in following the media news about the phosphate issue in the future. The five open-ended questions focused on understanding of the aspects that students liked and disliked about the hands-on activities and the digital learning environment. These questions were as follows: (1) Name the most important aspects you have learned (laboratory and PREZI). (2) Describe the aspects which you liked about the laboratory. (3) Describe the aspects which we might improve about the laboratory.

Table 2. Examples of the Categories for Question 4 (Our Translation) category design videos and pictures text/information understandable/ appropriate text/information interesting/instructive handling certain content multiperspectivity

definition optical attributes like a clear arrangement or design were described videos and/or pictures were mentioned the text and/or information were described as understandable and/or well written the text and/or information were described as interesting and/or instructive the handling was described as user-friendly and or easy to work with certain content of the learning environment was named (e.g., the island of Nauru) working based on different perspectives was mentioned

At the end of the day, the students were able to answer some critical questions regarding phosphate recovery including: How important are phosphorus and phosphates? What is phosphate needed for? How can it be recycled? Why it is so important?. From the feedback of the Likert items and open questions, it can be said that the experiments, the method of presentation, and the interdisciplinary learning environment were perceived very well by the high school students. E



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LIMITATIONS This design case has many limitations. It is a first of its kind and included a small group of students who completed experiments in a nonformal educational setting with its own specific characteristics. The focus in this study was on feasibility and the students’ perception of the innovation. Further research might also focus on other gains like chemistry content knowledge. It is also recommended that the study be repeated at different institutions and countries involving a larger number of high school or undergraduate students to determine if the experiences and findings will differ. Research should also reveal whether the topic and the experiments can also be integrated into formal education successfully at secondary schools or in undergraduate courses.

Ozcan Gulacar: 0000-0001-7709-0524 Ingo Eilks: 0000-0003-0453-4491 Notes

The authors declare no competing financial interest.

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ACKNOWLEDGMENTS We gratefully acknowledge the financial support of the Deutsche Bundesstiftung Umwelt (DBU). We thank the Chemische Fabrik Budenheim and hanseWasser Bremen for their cooperation.

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(1) Matlin, S. A.; Mehta, G.; Hopf, H.; Krief, A. The role of chemistry in inventing a sustainable future. Nat. Chem. 2015, 7, 941− 943. (2) Sjöström, J. Towards Bildung-oriented science education. Sci. & Educ. 2013, 22, 1873. (3) Hofstein, A.; Eilks, I.; Bybee, R. Societal issues and their importance for contemporary science education − a pedagogical justification and the state-of-the-art in Israel, Germany and the USA. Int. J. Sci. Math. Educ. 2011, 9, 1459−1483. (4) Zeidler, D. L. Socioscientific issues as a curriculum emphasis: Theory, research and practice. In Handbook of research in science education Lederman, N. G., Abell, S. K., Eds.; Routledge: New York, 2014; Vol. 2 pp 697−726. (5) Eilks, I.; Hofstein, A. Combining the question of the relevance of science education with the idea of education for sustainable development. In Science education research and education for sustainable development; Eilks, I., Markic, S., Ralle, B., Eds.; Shaker: Aachen, Germany, 2014; pp 3−14. (6) Sjöström, J.; Talanquer, V. Eco-reflexive chemical thinking and action. Current Opinion in Green and Sustainable Chemistry 2018, 13, 16−20. (7) United Nations (UN). Transforming our world: The 2030 agenda for sustainable development; United Nations: New York, 2015. (8) Steffen, W.; Richardson, K.; Rockström, J.; Cornell, S. E.; Fetzer, I.; Bennett, I. M.; Biggs, R.; Carpenter, S. R.; de Vries, W.; de Wit, C. A.; Folke, C.; Gerten, D.; Heinke, J.; Mace, G. M.; Persson, L. M.; Ramanathan, V.; Reyers, B.; Sörlin, S. Planetary boundaries: Guiding human development on a changing planet. Science 2015, 347 (6223), 1259855. (9) Bello, M. A.; González, A. G. Determination of phosphate in cola beverages using nonsuppressed ion chromatography - an experiment introducing ion chromatography for quantitative analysis. J. Chem. Educ. 1996, 73 (12), 1174−1175. (10) Xia, K.; Pierzynski, G. Competitive sorption between oxalate and phosphate in soil: an environmental chemistry laboratory - using ion chromatography. J. Chem. Educ. 2003, 80 (1), 71−75. (11) Storer, D. A.; Sarquis, A. M. Measuring soil phosphates using ion-exchange resins -a final project for freshman chemistry. J. Chem. Educ. 2000, 77 (6), 748−749. (12) Kriz, G. S., Jr.; Kriz, D. K. Analysis of phosphates in detergents. J. Chem. Educ. 1971, 48 (8), 551−552. (13) Kammler, D. C.; Truong, T. M.; VanNess, G.; McGowin, A. E. A service-learning project in chemistry: environmental monitoring of a nature preserve. J. Chem. Educ. 2012, 89, 1384−1389. (14) Heider, E. C.; Valenti, D.; Long, R. K.; Garbou, A.; Rex, M.; Harper, J. K. Quantifying sucralose in a water-treatment wetlands: service-learning in the analytical chemistry laboratory. J. Chem. Educ. 2018, 95, 535−542. (15) Schwarz, G.; Frenzel, W.; Richter, W. M.; Täuscher, L.; Kubsch, G. A multidisciplinary science summer camp for students with emphasis on environmental and analytical chemistry. J. Chem. Educ. 2016, 93, 626−632. (16) Burmeister, M.; Rauch, F.; Eilks, I. Education for sustainable development (ESD) and chemistry education. Chem. Educ. Res. Pract. 2012, 13, 59−68.

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CONCLUSION This paper presents a design case study on how new developments in environmental technology can be adapted to make chemistry learning relevant to students and embrace an interdisciplinary curriculum approach. It brings a sustainability-related socioscientific issue, which has great importance to the future of the world, into secondary chemistry teaching. It exemplifies how chemistry reacts to global challenges and presents how it attempts to recycle phosphate out of wastewater and sewage sludge. The topic offers a chance for students to gain experience with a current application of chemistry. It also shows that chemistry is necessary for a sustainable future and for limiting the impact of mankind on the environment.1 The use of chemistry experiments in combination with digital pre- and post-laboratory learning materials proved to be feasible for incorporating perspectives from biology, agriculture, economics, politics, and geography into chemistry education. Thus, this case provides hints to how systems thinking and chemistry teaching might be merged to overcome disciplinary boundaries as well as to promote education for sustainable development.32 The case proves the need for developing more activities similar to those described in this paper to learn more about how interdisciplinary chemistry learning can be effectively managed. Further studies are recommended to determine the influence of such implementations on students’ motivation and their perception of the relevance in chemistry learning and whether such approaches can also be successfully adopted for undergraduate chemistry teaching.

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ASSOCIATED CONTENT

S Supporting Information *

The Supporting Information is available on the ACS Publications Web site at DOI: (.DOCX) The Supporting Information is available on the ACS Publications website at DOI: 10.1021/acs.jchemed.8b01000. Laboratory guide on experiments (PDF, DOCX)

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AUTHOR INFORMATION

Corresponding Authors

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REFERENCES

C.Z.: [email protected]. A.S.: [email protected]. O.G.: [email protected]. I.E.: [email protected].

ORCID

Christian Zowada: 0000-0002-0522-464X F



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(17) Juntunen, M. K.; Aksela, M. K. Education for sustainable development in chemistry − challenges, possibilities and pedagogical models in Finland and elsewhere. Chem. Educ. Res. Pract. 2014, 15, 488−500. (18) Koutalidi, S.; Psallidas, V.; Scoullos, M. Biogeochemical cycles for combining chemical knowledge and ESD issues in Greek secondary schools part II: assessing the impact of the intervention. Chem. Educ. Res. Pract. 2016, 17, 24−35. (19) European Commission. Study on the review of the list of Critical Raw Materials − Criticality Assessments; publications.europa.eu/en/ publication-detail/-/publication/08fdab5f-9766-11e7-b92d01aa75ed71a1/language-en (accessed Mar 2019). (20) Koutalidi, S.; Scoullos, M. Biogeochemical cycles for combining chemical knowledge and ESD issues in Greek secondary schools part I: designing the didactic materials. Chem. Educ. Res. Pract. 2016, 17, 10−23. (21) Mayer, B. K.; Baker, L. A.; Boyer, T. H.; Drechsel, P.; Gifford, M.; Hanjra, M. A.; Parameswaran, P.; Stoltzfus, J.; Westerhoff, P.; Bruce, E.; Rittmann, B. E. Total value of phosphorus recovery. Environ. Sci. Technol. 2016, 50, 6606−6620. (22) European Commission. Report on Critical Raw Materials for the EU; www.catalysiscluster.eu/wp/wp-content/uploads/2015/05/ 2014_Critical-raw-materials-for-the-EU-2014.pdf. (accessed Mar 2019). (23) Food and Agriculture Organization of the United Nations (FAO). World fertilizer trends and outlook to 2020; http://www.fao. org/3/a-i6895e.pdf (accessed Mar 2019). (24) United States Geological Survey (USGS). Phosphate Rock. minerals; minerals.usgs.gov/minerals/pubs/commodity/phosphate_ rock/mcs-2017-phosp.pdf (accessed Mar 2019). (25) United Nations (UN). Western Sahara; www.un.org/undpa/ en/africa/western-sahara (accessed Mar 2019). (26) Killiches, F. Phosphat - Mineralischer Rohstoff und unverzichtbarer Nährstoff für die Ernährungssicherheit weltweit. 2013. Bundesanstalt für Geowissenschaften und Rohstoffe (Esd.), Hannover, on behalf of Bundesministerium für wirtschaftliche Zusammenarbeit und Entwicklung (BMZ). (27) Scholz, R. W.; Wellmer, F.-W. Approaching a dynamic view on the availability of mineral resources: What we may learn from the case of phosphorus? Global Environment Change 2013, 23, 11−27. (28) Cordell, D.; White, S. Peak phosphorus: clarifying the key issues of a vigorous debate about long-term phosphorus security. Sustainability 2011, 3, 2027−2049. (29) Chemische Fabrik Budenheim KG. Innovative process for the Recovery of phosphorus from sewage sludge; www.budenheim.com/ fileadmin/user_upload/Downloads/article/ExtraPhos_EN_2016-0707.pdf (accessed Mar 2019). (30) Mahaffy, P. G. Telling time: chemistry education in the Anthropocene epoch. J. Chem. Educ. 2014, 91, 463−465. (31) Vilches, A.; Gil-Pérez, D. Creating a sustainable future: some philosophical and educational considerations for chemistry teaching. Sci. Educ. 2013, 22, 1857−1872. (32) Mahaffy, P. G.; Krief, A.; Hopf, H.; Mehta, G.; Matlin, S. A. Reorienting chemistry education through systems thinking. Nat. Rev. Chem. 2018, 2, 0126. (33) Ben-Zvi Assaraf, O.; Orion, N. Development of system thinking skills in the context of earth system education. J. Res. Sci. Teach. 2005, 42 (5), 518−560. (34) Orion, N.; Libarkin, J. Earth system science education. In Handbook of research in science education; Lederman, N. G., Abell, S. K., Eds.; Routledge: New York, 2014; Vol. 2, pp 481−496. (35) Rempfler, A.; Uphues, R. System competence in geography education development of competence models, diagnosing pupilś achievement. Europ. J. Geograph. 2012, 3 (1), 6−22. (36) Gulacar, O.; Zowada, C.; Eilks, I. Bringing chemistry learning back to life and society. In Building bridges across disciplines for transformative education and sustainability; Eilks, I., Markic, S., Ralle, B., Eds.; Shaker: Aachen, 2018; pp 49−60.

(37) Meyer, C.; Steinmetz, H. Phosphorrückgewinnung mit dem “Stuttgarter Verfahren“. Wasserwirtschaft Wassertechnik 2013, 3, 24− 27. (38) Ostara. Nutrient Management Solutions; http://ostara.com/ nutrient-management-solutions/ (accessed Mar 2019). (39) Remondis SE & Co. KG Phoenix from the ashes; https://www. remondis-aktuell.com/en/032014/water/phoenix-from-the-ashes/ (accessed Mar 2019). (40) Eilks, I.; Ralle, B. Participatory Action Research in chemical education. In Research in Chemical Education - What does this mean?; Ralle, B., Eilks, I., Eds.; Shaker: Aachen, 2002; pp 87−98. (41) Hunter, W. Action Research. In Theoretical Frameworks for Research in Chemistry/Science Education; Bodner, G. M., Orgill, M., Eds.; Prentice Hall: Upper Saddle River, NJ, 2007; pp 146−164. (42) Laudonia, I.; Mamlok-Naaman, R.; Abels, S.; Eilks, I. Action research in science education - an analytical review of the literature. Educ. Action Res. 2018, 26 (3), 480−495. (43) Marks, R.; Eilks, I. Research-based development of a lesson plan on shower gels and musk fragrances following a socio-critical and problem-oriented approach to chemistry teaching. Chem. Educ. Res. Pract. 2010, 11 (2), 129−141. (44) Eilks, I.; Feierabend, T. Developing the curriculum by Participatory Action Research − An interdisciplinary project on climate change. In Educational design research: introduction and illustrative cases; Plomp, T., Nieveen, N., Eds.; SLO: Enschede, 2013; pp 321−338. (45) Stuckey, M.; Eilks, I. Raising motivation in the chemistry classroom by learning about the student-relevant issue of tattooing from a chemistry and societal perspective. Chem. Educ. Res. Pract. 2014, 15 (2), 156−167. (46) Hodson, D. Time for action: Science education for an alternative future. Int. J. Sci. Educ. 2003, 25 (6), 645−670. (47) Eilks, I.; Markic, S. Effects of a long-term Participatory Action Research project on science teachers’ professional development. Eurasia J. Math. Sci. Technol. Educ. 2011, 7 (3), 149−160. (48) Affeldt, F.; Weitz, K.; Siol, A.; Markic, S.; Eilks, I. A non-formal student laboratory as a place for innovation in education for sustainability for all students. Educ. Sci. 2015, 5, 238−254. (49) Affeldt, F.; Tolppanen, S.; Aksela, M.; Eilks, I. The potential of non-formal chemistry education for curriculum development and innovation - A perspective based on two cases from Finland and Germany. Chem. Educ. Res. Pract. 2017, 18, 13−25. (50) Mayring, P. Qualitative Inhaltsanalyse: Grundlagen und Techniken; Beltz: Frankfurt, 2015.

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