Secondary School Students’ Engagement with Environmental Issues via Teaching Approaches Inspired by Green Chemistry

Abstract

Green chemistry refers to the design and application of practices that prevent pollution and promote environmental sustainability. A set of 12 principles make up the core of the green chemistry philosophy, and, since their emergence, they have been implemented in the educational practice of tertiary education. Over the past few years, the green chemistry approach has started expanding among secondary education as well. This review discusses green chemistry teaching experiences in secondary education as reported in 70 scientific publications (from 2002 to the present) that were identified via a literature search. All identified documents were examined and analyzed to map their green chemistry content and relevant environmental issues, the degree of the connection between the chemistry concepts and environmental issues (“environmentalization”), the implemented teaching-learning approaches, and, when applicable, the achieved learning outcomes. Analysis showed that all 12 green chemistry principles were covered within the identified publications, with the ones referring to prevention and the use of renewable feedstocks being the most frequent. The publications touch upon several environmental issues, with the most frequent being those referring to hazardous chemical waste, alternative energy resources, and recycling. Most of the publications correspond to a medium degree of environmentalization. The inquiry-based, hands-on-based, problem-based, context-based, and socio-scientific issues-based teaching approaches were shown to be the most widely used. Regarding the achieved learning goals, those mostly explored were related to the cognitive and affective domains. This comprehensive review may provide a solid foundation for the organization and design of novel curricula that will integrate green chemistry into education for sustainable development programs in secondary education.

1. Introduction

Green chemistry (GC) made its appearance in the 1990s and refers to the design and application of practices that prevent pollution and promote environmental sustainability. A set of 12 principles makes up the core of the green chemistry philosophy [1,2] and have provided the basis for the formation of education for sustainable development programs [3,4,5,6]. Since their emergence, these principles have been implemented extensively in the educational practice of tertiary chemical education. This has led to the development of a multitude of teaching materials aimed at promoting students’ competence for systems thinking and societal decision-making within the framework of sustainability [3].

Over the past half century, environmental education has emerged as a consequence of both the demand for reducing the negative impacts of human activity on the environment and the increase in interest for socio-scientific issues, such as ecological degradation, population-resource issues, and global warming. Environmental education encourages students’ active learning, field-based learning, the investigation of community issues and systems thinking [7,8,9]. At the end of the 20th century, a shift from environmental education to education for sustainable development (ESD) was made. ESD has been characterized as a critical-reflective approach that integrates science learning with environmental issues by also taking into account the societal and economical aspects of the latter [10]. Green chemistry education has progressed as a response of traditional chemistry education to ESD and is portrayed via the incorporation of green chemistry principles, concepts, and practices in science education with various ways [10,11]. Similar to ESD, green chemistry education is aimed at the development of general educational skills, concentrating on the learner’s actions as a responsible citizen [10,12]. While several tertiary education institutions (e.g., University of California, Berkeley—USA; Yale University—USA; University of Padua—Italy; and University of York—UK) have already transformed their curricula by incorporating the principles of green chemistry and the notion of sustainability, the integration of green chemistry in secondary education is less frequent. Although green-sustainable chemistry education is viewed favorably by most chemistry teachers, many of them have difficulty incorporating it into their classes due to their lack of experience and pedagogical content knowledge [13,14].

In this context, as well as considering how green chemistry relates to environmental issues more widely, we decided to conduct a literature review to map the integration of green chemistry into both lower and upper secondary education chemistry curricula (with the upper ones being more frequent). The analysis of the reviewed documents also focuses on the implemented teaching approaches and the corresponding teaching-learning goals of these curricula.

2. Background

2.1. Teaching-Learning Approaches in Green Chemistry Education

There is much research evidence that students’ knowledge-building in science classrooms should be similar to the process by which science knowledge is built up by science researchers. In fact, the ‘doing science like a scientist’ approach has shifted the focus of science education worldwide from the individual to the social context. Although the discovery approaches, popular since the 1960s, were based on the idea that students ‘doing science like scientists’ should focus on cognitive outcomes, there is wide agreement that these approaches neglect the cultural, social, and affective dimensions of science [15]. In addition, there is research evidence that different teaching approaches lead to various student conceptions of what doing science means within the context of chemistry as a scientific discipline [16]. Research focusing on learning theories during the last decades [17] has elicited changes in educational practice. As a result of these research efforts, a series of student-centered teaching strategies have been introduced, including context-based, argumentation-based, case-based, project-based, problem-based, socio-scientific issues-based, inquiry-based, and a hands-on approach to teaching and learning. The last two approaches are especially suitable for learning experimental sciences such as chemistry.

The argumentation-based approach uses language activities such as argumentation and reading-writing in the classroom, thus enhancing students’ ability to “negotiate on conceptual understanding and develop individual writing and reflection skills” [18]. The process of argumentation, which is at the center of this approach, may be defined as “students’ as well as teachers’ reasoning with evidence, justifications, and claims” [19]. During and after the argumentation process, students participate in discussion activities both in small groups and within the whole classroom.

The case-based approach is defined as using cases, namely well-written scenarios often presented as dilemmas, which allow students to use ideas along emotional and intellectual dimensions [20]. These cases help learners understand the relevance of chemistry in society, involving “learning by doing, the development of analytical and decision-making skills, the internalization of learning, learning how to grapple with messy real-life problems, the development of skills in oral communications, and often teamwork” ([21] p. 30). The different forms of case-based teaching approaches appear in various class sizes and time lengths.

The context-based (CB) approach in chemistry education is defined as the teaching-learning process that puts a context or a real-world application of chemistry at the center of chemistry teaching and thereby making students use chemistry concepts to achieve meaningful understanding [22]. CB approaches are considered as a response to students’ decreased interest in chemistry, which may be partially attributed to the lack of connection between the chemistry curriculum and students’ everyday life experiences [14]. Thus, the CB teaching-learning movement aims to bring chemistry closer to students’ lives, and despite some criticism, there is much research evidence for the positive effects of context-based learning (CBL) on students’ understanding of chemistry as well as on their attitudes toward it [22]. Green chemistry is often used as context for CB teaching-learning in chemistry because it relates to the economic, societal, as well as environmental aspects of sustainability. CB approaches facilitate learning on sustainable development, and they are most easily implemented in the applied aspects of chemistry where the real-life contexts are readily identified.

The hands-on based approach guides students to be actively involved in manipulating materials and instruments. Hands-on activity holds an important role in science education and provides both advantages and disadvantages. Several studies have shown that regularly incorporated hands-on units can enhance cognitive achievement, but on the other hand, spontaneously implemented hands-on activities do not elicit specific positive outcome on achievement, even though students’ motivation is enhanced [23].

The inquiry-based approach involves students’ engagement with scientific practices such as making observations, drawing inferences, building hypotheses, designing investigations, setting up variables, data gathering, and interpreting and disseminating results. This approach is a more representative way of ‘doing science like a scientist’. During inquiry, students’ social interactions are high, as they are encouraged to ask questions, share ideas, and get involved in dialogue. In this way, students form a team with strong interdependency, which allows for enhanced collective benefits. All students must be encouraged to participate actively to ensure equal opportunities [24].

The problem-based approach encourages students to participate actively in examining solutions of ill-structured real-world problems, thus promoting the integration of concepts and skills required for dealing with real-life situations. It constitutes a student-centered teaching-learning approach “that involves independent study, group discussions, research, reflection on research, and presentation” [25]. The guiding principle of problem-based learning is that the learning process is the result of intellectual exploration in combination with active collaboration. Consequently, the promotion of creative thinking and self-regulated learning are some of the benefits of the problem-based approach in chemistry education. These skills are especially important within green chemistry, given the subject’s complexity and interdisciplinary nature [26].

The project-based approach refers to an inquiry-based teaching approach that promotes learners’ knowledge construction by encouraging them to complete “meaningful projects and develop real-world products” [27]. The characteristics of project-based teaching-learning approach include the following: a guiding question, concentrating on learning goals, participation in educational activities, student collaboration, employing scaffolding technologies, and the creation of tangible artifacts. The last of these characteristics is most crucial because it distinguishes project-based from other student-centered teaching approaches. This process of creating a tangible artifact requires students to work collaboratively in order to propose “solutions to authentic problems in the process of knowledge integration, application, and construction” [27].

The socio-scientific issues (SSIs)-based approaches refer to a pedagogical model comprising three strands: (a) levels of reasonable disagreement, (b) communicative virtue, and (c) modes of thought. Nine levels of reasonable disagreement described in Levinson [28] define SSIs as the presentation of a broad range of society-based conflicts between science and socio-ethical considerations with regard to a controversial issue and relate the challenges that students must face. In this way, the conflicts associated with the SSIs constitute the context for science instruction [29]. The communicative virtue represents a set of activities that are based on discussion and in which students can share ideas, enact different perspectives, and reason towards conflict resolution [30]. The modes of thought constitute higher order thinking skills, which include scientific knowledge and reasoning related to ethical considerations, emphasizing what students can achieve when coping with SSIs [28,30]. Modes of thought can also be demonstrated as decision-making or argumentation skills, and they are not limited to mental processes such as thinking or reasoning [29].

2.2. Teaching and Learning Goals

Notwithstanding the employed teaching-learning approach, chemistry teaching and learning goals in educational contexts focus on four main domains: (a) the affective domain, which includes aspects such as attitudes, interests, motivation, or values [31]; (b) the cognitive domain, which involves “the conceptual structures and cognitive processes used when reasoning scientifically” [32]; (c) the epistemic domain, which includes the frameworks used for the development and evaluation of scientific knowledge; and (d) the social domain, which refers to “processes and contexts that shape how knowledge is communicated, represented, argued, and debated” [32]. Bloom’s taxonomy regarding the educational objectives of the cognitive domain is widely adopted by the science education community in contrast to his work on the affective domain, which is less cited. Moreover, the affective and cognitive domains should be considered in conjunction. Taber [33] argued that teaching focused on cognitive perspectives on learning would be more effective when it also focuses on affect. He suggested that the traditional emphasis “on what is learnt should be supplemented by a simultaneous consideration of how learning activities are experienced by the students”.

The integration of the cognitive and affective domain represents a fundamental principle of environmental education promoting multi-level awareness, including (a) self-awareness, which mirrors how an individual’s lifestyle choices affect the natural environment; (b) social awareness, which delineates how individual choices are influenced by social interaction; and (c) environmental awareness, which refers to how the political choices of human society impact the ecosystems [34]. There is evidence that students with science knowledge can be more environmentally active than those with poorer knowledge. Thus, the importance of providing appropriate chemistry education that supports environmental issues is justified.

2.3. Models of Green Chemistry Inclusion in Chemistry Education

Four basic models regarding the inclusion of green chemistry in chemistry education have been proposed by Burmeister and colleagues [3]. Model I: the adoption of the principles of green chemistry to laboratory practices. Model II: employing green chemistry themes to contextualize learning of chemistry content. Model III: using socio-scientific issues-based projects in order to address technological and environmental challenges via practices of green chemistry. Model IV: a holistic approach in which science/green chemistry education is seen as part of the sustainability-driven development of school life.

Model I may be readily applied in chemistry classes through micro-scale experiments, the selection of less toxic materials, and more environmentally benign reagents and solvents. The obvious strong aspect of this approach is that chemistry education directly contributes to sustainability via the reduction of materials used and the waste produced. In fact, many school laboratories have large inventories of chemicals that often include highly hazardous or expired substances. The processes of green chemistry aim to substitute hazardous chemicals with benign materials. However, the weakness of this approach with respect to ESD is that it usually does not promote self-reflection on societal issues [3]. Thus, students are unlikely to develop the necessary skills that will enable them to advance sustainability transformations as future citizens.

Model II is based on the strategies and efforts used to contribute to sustainable development in order to decide the content that will be included in chemistry education. Environmental issues are used to connect chemistry knowledge to concerns familiar to students. According to Pilot and Bulte [35], students’ motivation to learn chemistry is enhanced when learning is related to everyday life experiences and issues. Practical examples of such content related to ESD include, for example, biofuels, benign catalysts, and biodegradable plastics. The context-based approach of Model II can provide the initial step that offers learners exposure to sustainability issues as they appear in modern chemistry [3].

Model III is based on using controversial issues related to sustainability, such as socio-scientific issues, for driving chemistry education. Socio-scientific issues (SSIs) essentially comprise questions that are both philosophical and empirical in nature. SSIs contain disputes among the three pillars of sustainable development, namely environment, society, and economy, which are often mutually conflicting and whose resolution cannot be achieved solely via scientific approaches [36]. This model is often applied in secondary education since it enables students to engage in active citizenship and become prepared and willing to take personal and social actions for environmental risk reduction and protection.

Model IV promotes the idea that school life and teaching should be integrated into the approach of ESD. In order to educate young people to become active citizens who have the ability to follow sustainable lifestyles, a holistic reform of the current school models is required. ESD schools have chosen the principles of education for sustainable development as a major part of their function and educational orientation. Sustainability is considered as a main principle during planning of the school’s daily activities as well as its long-term development. These schools are committed to inducing profound changes regarding the aims and roles of educational institutions. They aim to offer students context for developing active citizenship via systematically exposing them to the three interrelated dimensions of sustainable development [37]. This model is also referred to as lived ESD [5].

The above four models can be classified as holding differing degrees (ranging from weak to strong) of chemistry environmentalization. The term “environmentalization” refers to the extent to which a knowledge area (chemistry in our case) takes into consideration “the interests of society in combination with the corresponding environmental and health threats” [10]. Weak environmentalization (on one end) can be conceptualized as focusing on technical solutions (Model I: adopting green chemistry practices in the school chemistry laboratory) while strong environmentalization (on the other end) can be conceptualized as actions based on an understanding of science, technology, society, and environment relationships (Model IV: making ESD an integral part of school life and teaching) [3].

3. Method

The purpose of this study is to identify the GC principles introduced in secondary chemistry education in order to engage students with environmental issues. Furthermore, our research aims to reveal the teaching approaches, chemistry topics, and levels of ‘enviromentalization’ that promote this engagement. A method of a three-step review was followed. In the first step, the identification of GC secondary education-related publications was conducted by searching the Web of Science (WoS) database. In this search, the keywords “green chemistry”, “sustainable chemistry”, “secondary education”, “high school”, and “middle school” were used to seek in paper titles, abstracts, and keywords covering the period until June 2024.

In the second step, editorials, reviews, news, articles related to secondary teacher education etc. were removed from the search results. Additionally, publications written in languages other than English were excluded, and a total of 70 publications [38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107] were selected as the study sample (data papers). The procedure of sample selection arises as the main limitation of this study. More specifically, some subjectivity is introduced due the choice of database, keywords, and language of the publications.

In the third step, an analysis of these 70 publications was made by the classification of their contents by means of categories related to year of publication, origin of publication, environmentalization, GC content, teaching-learning approach, teaching-learning goals, environmental issues examined, and related chemical topics. The analysis was deductive as the categories and their coding were predetermined based on the literature discussion, which is presented in the background section on this paper. These categories express a set of aspects that identify what, where/what for, how, and for whom each publication is intended.

4. Results and Discussion

4.1. Temporal Distribution

All identified publications with GC secondary education-related content appeared after 2010, except for one [52], which was released in 2002 (Figure 1). This eight-year gap can be attributed to the stepwise approach that is generally adopted, namely, green chemistry was initially integrated in tertiary education to train teachers, trainers, book writers, and decision-makers and then in secondary school for educating scientifically literate students. Among the 69 most recent publications (between the years 2010–2024), the majority (42, 60% of the total) appeared after 2018, i.e., during the second half of the period between 2010–2024. This fact is indicative of the continuously growing interest and effort for the incorporation of the GC pedagogical approach among secondary school students.

4.2. Geographic Distribution

The geographic distribution of the publications (shown in Figure 2) reveals a representation of all continents, although at varying degrees. More specifically, the largest portion (58 publications, ca. 83% of the total) contains at least one author affiliated with either the Americas (Brazil, Canada, and the USA; 28 publications) or Europe (Germany, Finland, UK, Greece, Netherlands, Austria, Denmark, Italy, Portugal, and Slovakia; 30 publications) with approximately equal share between the two continents. Subsequently, 18 publications (ca 26% of the total) contain at least one author affiliated with a country located in the Asian continent (Malaysia, Indonesia, Thailand, China, India, and Israel). Finally, Africa (South Africa) and Oceania (Australia) are represented at the smallest degree with one and four publications, respectively. It is noted that 11 out of the 70 identified publications (ca. 16%) have resulted from the collaboration of researchers located in two different countries. At the continent level, these 11 collaborative publications [48,66,71,72,73,84,103,104,105,106,107] contain five different combinations: Europe–Americas [48,66,105,107], Europe–Asia [84,106], Europe–Oceania [103,104], Americas–Asia [72,73], and Asia–Oceania [71]. Despite the identified publications originating from a rather small number of countries (21), their distribution, in addition to the existence of collaborations, indicates an increasingly expanding research field.

4.3. Degree of Environmentalization

The “environmentalization” category allows an overview of the connections between chemistry concepts and environmental issues. The four models of inclusion of GC to chemistry education [3] correspond to different levels of environmentalization in increasing order as follows: technically applying green chemistry practices in the school chemistry laboratory (Model I—weak environmentalization), using green chemistry issues to contextualize chemistry content (Model II—medium-low environmentalization), addressing technological and environmental challenges through green chemistry in SSI-based projects (Model III—medium-high environmentalization), or understanding of green chemistry education as part of the sustainability-driven development of school life (Model VI—strong environmentalization). Examination of the 70 identified publications with regard to this criterion led to the following results: Eighteen publications [23,24,28,33,34,35,36,42,43,46,47,56,57,62,63,65] are concerned with the experimental application of green chemistry practices in the school chemistry laboratory (Model I); twenty five publications [39,45,47,49,50,51,53,54,59,74,75,76,77,79,81,82,85,87,89,95,96,97,98,101,105] propose curricular material that use green chemistry issues as context for teaching specific chemistry content (Model II); twenty six publications [38,40,41,44,48,52,55,56,57,58,62,63,64,66,67,68,69,78,88,90,91,92,103,104,106,107] provide green chemistry in SSI-based projects (Model III); and no publications were found to implement Model IV. One publication [86] was not assigned to any inclusion model because it deals with the development of an instrument for evaluating students’ understanding and does not refer to some type of educational intervention.

At this point, it should be noted that the four inclusion models show, in accordance with their differing environmentalization level, a diverse capacity with respect to their contribution to ESD and specifically regarding their potential for either “learning about sustainable development” or “learning for sustainable development”. As noted by McKeown [108], “the first is an awareness lesson or theoretical discussion. The second is the use of education as a tool to achieve sustainability”. Educational approaches that primarily aim at learning ‘for’ sustainable development help education serve its purpose in society by “giving people knowledge and skills for lifelong learning to help them find new solutions to their environmental, economic, and social issues” [108]. Thus, the inclusion models III and IV have a very high potential with respect to ESD as education ‘for’ sustainable development, while the corresponding potential of Models I and II is low [3]. The fact that a quite large number of the identified publications (26, ca. 37% of the total) propose GC teaching applications by making use of socio-scientific issues of controversial nature (Model III) indicates the increased potential of green chemistry pedagogy for shaping secondary school students into empowered citizens with environmentally responsible behavior. The absence of publications related with Model IV, which corresponds to the highest degree of environmentalization (strong), is perhaps not surprising since this model presents the largest practical difficulties for its implementation and requires the most highly trained teachers.

4.4. Green Chemistry Content

The “GC content” category includes the information on whether a publication refers directly or indirectly to the 12 green chemistry principles. The GC principles, on which the described curriculum materials are mostly focused, are the following four (Figure 3), with their definitions taken from Anastas and Warner [1]: (P1) Prevention: It is better to prevent waste than to treat or clean it up after being formed [39,40,41,43,44,45,46,48,50,51,53,57,59,60,62,65,70,71,72,73,75,79,80,81,82,85,87,88,89,90,91,92,94,95,97,98,99,102,103,104,106,107]; (P7) Use of renewable feedstocks: A raw material or feedstock should be renewable rather than depleting whenever technically and economically plausible [39,40,43,44,45,47,48,52,53,54,55,56,58,59,61,63,66,67,68,69,70,75,76,77,78,79,82,86,87,89,90,91,98,99,102,103,104,105,106,107]; (P6) Design for energy efficiency: Energy requirements of chemical processes should be minimized [38,39,40,44,48,49,55,56,58,59,67,68,69,70,79,82,83,84,85,86,90,92,99,102,103,104,105]; and (P10) Design for degradation: The synthesis of chemical products, which after their use break down into benign, non-persistent degradation products, is required [40,44,47,48,53,54,63,66,67,68,69,70,76,77,79,81,82,90,92,93,99,102,103,104].

4.5. Teaching-Learning Approaches

The “teaching-learning approach” category (Figure 4) includes proposals, assessments, and/or reports involving GC teaching strategies discussed in each publication. The following five types of approach are most frequently used: (i) inquiry-based [38,42,47,50,54,58,59,62,67,76,78,79,87,89,92,97,99,100,101]; (ii) hands-on-based [39,53,60,82,83,84,85,89,91,93,95,96,98,99,100,101]; (iii) problem-based [40,43,44,46,52,55,56,59,61,75,88,106,107]; (iv) context-based [40,58,59,70,72,74,81,82,90,103,104]; and (v) socio-scientific issues-based [43,44,46,48,55,56,58,59,75,88,107]. Laboratory-, project-, case-, and argumentation-based approaches are used less frequently.

Taking into account that an essential expected outcome of ESD is the development of a specific set of nine competences that are relevant to sustainability [5], it is important to note that the four most often used teaching-learning approaches listed above are indeed suitable for achieving this aim. In fact, among the nine proposed ESD competences, at least seven of them could be developed via the application of the four identified teaching-learning approaches. A more detailed examination leads to the following conclusions.

The competence referring to “systems thinking” is promoted via the SSI-based approach. In addition, the literature provides evidence for the interconnection of systems thinking with green chemistry in the context of chemistry education [109]. The “problem-solving” competence can be developed via the problem-based approach. The competence related to “critical thinking” is fostered via the SSI- and inquiry-based approaches. The problem- and SSI-based approaches, as well as the engagement of students with authentic problems via the context-based approach, can promote the “action competence”. Students’ “normative competence” (related to empathy, solidarity, attitudes, and values) can be developed via the SSI-based approach. Finally, the competence related to communication and collaboration is fostered especially via the inquiry-based approach.

4.6. Teaching-Learning Goals

Regarding the teaching-learning goals of the reviewed publications, the most frequent are the ones related to the affective and cognitive domains, which appear either alone or in combination with other domains (Figure 5). It should be noted that this analysis was conducted solely on the 48 publications [38,39,40,41,43,44,45,46,47,48,49,50,52,54,55,56,57,58,60,61,62,65,67,68,70,71,72,73,74,75,76,82,85,87,88,89,90,91,93,94,95,96,100,101,103,104,106,107] that provided some type of evidence related to the achieved teaching-learning goals. The goals connected with the affective domain mentioned in 27 reviewed publications [38,39,40,41,44,45,46,47,55,56,57,58,61,62,67,70,71,72,82,87,93,94,95,96,100,103,106] are related to students’ interest, enjoyment, attitudes, motivation enhancement, confidence, and inspiration for pursuing a career in STEM fields. The goals related to the cognitive domain, which are mentioned in 39 reviewed publications [44,46,48,49,50,54,55,56,57,58,60,62,65,67,68,70,71,72,73,74,75,76,82,85,87,88,89,90,91,93,94,95,96,100,101,103,104,106,107], refer mainly to the improvement of students’ understanding, development of argumentation and critical thinking skills, and reduction of misconceptions. The goals related to the social domain refer mostly to students’ personal development, communication and social skills, and cooperative learning, and these are met in eight of the reviewed publications [52,55,56,58,67,68,75,91]. The goals of the epistemic domain are met in 14 publications [47,54,55,58,61,62,85,87,89,90,91,104,106,107], and they refer mainly to students’ participation in authentic research experiences and the enhancement of their interest in taking up research, their intellectual engagement, the perception of science relevance with everyday life, and the development of socio-economic and ethical arguments. Students’ environmental awareness is explicitly stated as a goal in 11 publications [43,48,61,62,67,82,85,87,90,91,101]. In addition, specific reference to metacognitive goals is made in two of the reviewed publications [103,104]. It should be noted that, besides the cognitive goals, the emphasis given to the affective goals in several publications (27 out of the 48 that make reference to teaching-learning goals) brings out the crucial importance of this domain for a more effective chemistry education.

4.7. Environmental Issues

The examination of the identified publication, with respect to the environmental issues they are focusing on, led to the following results. The five predominant issues (dealt with in more than five publications) are (a) hazardous chemical waste, (b) alternative energy resources, (c) recycling, (d) climate change, and (e) biodegradable materials. In addition, the environmental issues related to renewable feedstocks, water quality, life cycle thinking/analysis, acidification, and ozone depletion are mentioned in more than one publication.

Table 1. Categorization of publications according to the environmental issues examined.

Environmental Issues	References
Hazardous chemical waste: pesticide residuals, microplastics in oceans, toxicity, etc. (18 publications)	Ballard and Mooring, 2021 [41]; Chonkaew et al., 2019 [46]; Duangpummet et al., 2019 [50]; Hoffman and Dicks, 2020 [62]; Hudson et al., 2017 [64]; Khamhaengpol et al., 2022 [75]; Liu et al., 2023 [85]; Mellor et al., 2018 [90]; Murphy et al., 2019 [92]; Redhana et al., 2021 [94]; Rossi and Serpe, 2024 [95]; Scheid et al., 2021 [96]; Schiffer et al., 2019 [97]; Sutheimer et al., 2015 [100]; Vogelzang et al., 2020, 2021 [103,104]; Zidny and Eilks, 2020 [106]; Zowada et al., 2020 [107]
Alternative energy resources: fuel cells, biofuels, etc. (14 publications)	Aksela and Boström, 2012 [38]; Albright et al., 2021 [39]; Aubrecht et al., 2015 [40]; Cannon et al., 2021 [45]; Eilks 2002 [52]; Feierabend & Eilks 2011 [56]; Garner et al., 2015 [58]; Kapassa and Abeliotis, 2013 [69]; Karpudewan 2020 [70]; Karpudewan et al., 2012; 2015 [71,72]; Khamhaengpol et al., 2022 [75]; Kohn 2019 [78]; Silveira et al., 2017 [98]
Recycling (11 publications)	Aubrecht et al., 2015 [40]; Bopegedera and Perera, 2017 [43]; Diekemper et al., 2019 [49]; Enthaler 2017 [53]; Fagnani et al., 2020 [54]; Gupta and Mishra, 2020 [60]; Hudson et al., 2015 [63]; Koulougliotis et al., 2021 [79]; Liu et al., 2023 [85]; Murphy et al., 2019 [92]; Rossi and Serpe, 2024 [95]
Climate change: global warming, greenhouse effect, etc. (9 publications)	Burmeister and Eilks, 2012 [44]; Feierabend and Eilks, 2010 [55]; Finkenstaedt-Quinn et al., 2018 [57]; Garner et al., 2015 [59]; Karpudewan 2020 [70]; Khamhaengpol et al., 2022 [75]; Koulougliotis et al., 2021 [79]; Mandler et al., 2012 [87]; Wallington et al., 2013 [105]
Biodegradable materials: e.g., bioplastics (9 publications)	Aubrecht et al., 2015 [40]; Burmeister and Eilks, 2012 [44]; Hudson et al., 2015 [63]; Kapassa and Abeliotis, 2013 [69]; Karpudewan 2020 [70]; Knutson et al., 2017; 2019 [76,77]; Ma and Shengli, 2020 [86]; Redhana and Suardana, 2021 [93]
Renewable feedstocks (7 publications)	Burmeister and Eilks, 2012 [44]; Corcoran et al., 2022 [47]; Hartwell 2012 [61]; Kapassa and Abeliotis, 2013 [69]; Linkwitz and Eilks, 2022 [82]; McCance et al., 2021 [89]; Murphy et al., 2019 [92]
Water quality (6 publications)	Aubrecht et al., 2015 [40]; da Silva Júnior et al., 2024 [48]; Mandler et al., 2012 [87]; Mellor et al., 2018 [90]; Mistry and Hurst, 2022 [91]; Silveira et al., 2017 [98]
Life cycle thinking/analysis (5 publications)	Eaton et al., 2019 [51]; Enthaler 2017 [53]; Jefferson et al., 2020 [66]; Juntunen and Aksela, 2013; 2014 [67,68]
Acidification: acid rain, acidification of oceans, etc. (4 publications)	Aubrecht et al., 2015 [40]; Cannon et al., 2021 [45]; Finkenstaedt-Quinn et al., 2018 [57]; Hwa and Karpudewan, 2017 [65]
Ozone depletion (2 publications)	Finkenstaedt-Quinn et al., 2018 [57]; Garner et al., 2015 [59]

presents the relevant citations for each environmental issue.

4.8. Chemical Topics

With regard to the chemical topics that are addressed by the reviewed publications, a large portion refer to organic chemistry (23). Other topics/areas include kinetics (14), reactions (11), polymers (9), acid-base (8), bonding (8), energy-thermodynamics (8), chemical analysis (5), solvent (5), structure (5), stoichiometry (4), electrochemistry (3), equilibria (3), states of matter (3), and environmental chemistry (1).

4.9. Green Chemistry Content—Degree of Environmentalization Correlation

Finally, the green chemistry principles and the model of their integration in chemistry education (Models I–IV, corresponding to an increasing degree of environmentalization) were cross tabulated to quantify possible correlations. Statistical analysis showed that only one GC principle, namely, “Use of Renewable Feedstocks” (P7), is significantly correlated with the model of green chemistry integration in the chemistry curriculum (Pearson χ² = 9867, df = 3, p < 0.050). Specifically, the curriculum materials that focus on principle P7 (“Use of Renewable Feedstocks”) tend to make more use of Model III (addressing technological and environmental challenges through green chemistry in SSI-based projects) at the expense of Model I (adoption of the GC principles to practices of the school science laboratory).

5. Concluding Remarks

In this study, a comprehensive literature review resulted in the identification of several published studies by educational researchers from all continents that report the possibility of applying the philosophy and practices of green chemistry in secondary education and not only at the university level. The possibility to influence the environmental consciousness of young non-adult citizens via their exposure to GC philosophy may further promote the aims and scope of ESD. Deductive analysis of a total of 70 identified publications, covering a period from 2002 to the present (mid-2024), provided significant insights with regard to the following: the degree of environmentalization, the teaching-learning approaches employed and the corresponding goals achieved, the relevant GC principles, the chemical topics, and the various relevant environmental issues. The majority of the identified publications (51 out of 70) correspond to a medium degree of environmentalization, almost equally distributed between medium low (25 publications) and medium-high (26 publications). Specifically, in 25 publications, green chemistry issues are used to contextualize chemistry content, and in 26 publications, SSI-based projects are used to address technological and environmental challenges via practices of green chemistry. The inquiry-based, hands-on-based, problem-based, context-based, and SSI-based teaching approaches were those that more frequently met among the 70 identified publications (identified in more than 10 publications). Regarding the achieved learning goals, those mostly explored were related to the cognitive and affective domains in 39 and 27 publications, respectively. All 12 GC principles were dealt with in the 70 identified publications, with the more frequent ones being P1—Prevention and P7—Use of Renewable Feedstocks, in 42 and 40 publications, respectively. Topics related to organic chemistry were the most frequent (23 publications). Several environmental issues (a total of 10) were dealt with in the 70 identified publications, with those referring to hazardous chemical waste, alternative energy resources, and recycling being the ones that were found more often (in more than 10 publications). The main limitation of the current study is related to the procedure for sample selection (e.g., choice of database and keywords).

Green chemistry education can be used as a scaffold in the education for sustainable development and vice versa [3]. The identified materials, with respect to the environmental issues employed and the related chemical topics, may provide valuable help to teachers for selecting the appropriate content and context in their effort to implement GC in their chemistry classes. The teaching-learning approaches for GC implementation in secondary education, as identified in this work, may also be highly beneficial for teachers who serve ESD. In fact, these approaches may promote the development of several ESD competences, such as systems thinking, problem-solving, critical thinking, action competence, normative competence, communication, and collaboration.

The documented possibility to achieve a variety of educational goals in the affective, cognitive, epistemic, and social domains among young non-adult students shows the potential of GC philosophy for shaping future responsible citizens who will be respectful towards other human beings as well as the planet and everything it provides.

Future research efforts should concentrate on thoroughly exploring, via quantitative and qualitative methods, the educational outcomes of specific GC-inspired educational interventions at both lower and upper secondary school in a combination of at least two domains (e.g., cognitive and affective, cognitive and epistemic, etc.). Research should be conducted among students of different demographics. Finally, more intense research is needed regarding the views and attitudes of the teachers who are called to implement GC-based teaching-learning approaches.