MIRANDA, Igor de Sousa. Et al. Using waste as a tool for environmental education and chemistry teaching. Revista Científica Multidisciplinar Núcleo do Conhecimento. 04 year, Ed. 07, Vol. 10, pp. 70-86. July 2019. ISSN: 2448-0959, Access link: https://www.nucleodoconhecimento.com.br/quimica-en/using-waste, DOI: 10.32749/nucleodoconhecimento.com.br/quimica-en/using-waste
The main objective of this work is to produce gypsum and ecological paint with residues of eggshells. Furthermore, we know that the reuse of these wastes aims to obtain new materials, so it becomes an indispensable tool for students in the reflection on environmental issues in their own community. This awakens in the child a greater capacity to evaluate the importance of preserving the environment for the health of the society to which it is inserted. Every development of the study revolves around the awareness of the environment and the teaching of chemistry as a stimulating tool. To this end, an activity program with all the institute’s 2nd grade students was organized on the IFPA campus of óbidos-PA. We elaborated the project with the community and the collections were carried out over a period of one week, being compared the amount of garbage produced by the residences and commercial points. The egg shell residues were treated and used as raw material for gypsum and ecological paint production. The community had the opportunity to participate in the environmental week produced by IFPA, where the results of the students’ work were demonstrated. The final result of the work was satisfactory, because the objective of producing industrial materials by the use of eggshells as a proposal to teach environmental and chemical education was achieved. The results in the written evaluations showed that the concept of content was effectively fixed and understood by the students, thus learning was more significant since it stimulated creativity among students and research as a tool for learning chemistry and the formation of the citizen with environmental and social awareness.
Keywords: Environmental Education, Plaster, Ecological Paint, Chemistry, Experimentation.
The National Curricular Parameters (NCP´s) of high school chemistry basically establish a common relationship between the sciences that make up the area, this relationship consists of the investigation of nature and technological development as a parameter that the school must share and articulate as a common language that creates a scientific culture capable of producing a school knowledge related to concepts of everyday life and the cultural universe of this science.
Even though there are these parameters that guide how to articulate a content within the discipline of chemistry, the difficulties of the relationship between teaching and learning chemistry have become the subject of debate nowadays, because most students cannot relate the contents taught with their daily lives (PAZ, et al. 2010).
Following the common idea that education is based, which is the formation of citizens with social and environmental awareness, we can highlight chemical science and environmental education as stimulating tools to raise awareness of environmental problems, forming in this context citizens with greater environmental and social awareness.
According to SANTOS, et al (2011) the learning of chemistry as an instrument for environmental education can transform teaching into a process of permanent valorization of the various forms of knowledge with the objective of forming a citizen who has local and planetary awareness. In this context, the author proposed to use garbage and recycling as a motivating theme to approach chemical content related to some social and environmental issues. Following this theme, the content passed on provided the student with a scientific and critical perception of the problem presented, making learning more dynamic and meaningful.
During the research, students selected an environmental problem that has been increasing in recent years, which was also worked as a motivating theme for science teaching, this theme, related to industrialization and the increase in egg consumption worldwide, because as a result, the number of residues of eggshells has increased significantly in recent years. According to FREIRE et al. (2006) in Brazil alone, approximately 120,000 tons of eggshell are generated per year, most of which are improperly dumped into the environment, thus contributing to the increase in environmental impacts.
Considering this problem, several authors have been studying the composition of egg shell residues and various ways of reusing them as a source of raw material for industries. For example, FREIRE et al. (2008), when conducting a study on eggshell, noticed through X-ray Diphratogram analyses that this residue is predominantly composed of calcium carbonate, an essential component in the formulation of calcium silicate and the main source for industrial production of calcium oxide. The same author also mentions that, through thermogravimetric analyses, it was possible to predict that the calcium carbonate present in the egg shell decomposes into calcium oxide basically at a temperature equal to or above 800ºC.
According to VIEIRA (2004), calcium carbonate powder, obtained from the eggshell, can act as an agent in the removal of heavy metals in aqueous medium, and RODRIGUES et al. (2015) presented the possibility of reusing eggshell as a source of CaCO3 and CaO, especially in the pharmaceutical industry that could produce drugs for people who have health problems related to lack of calcium in the body. Another possibility also mentioned is the application of these residues in vegetable gardens or land destined to the cultivation of plantations, aiming at the correction of the pH of very acidic soils.
According to SOARES (2005), by mixing calcium carbonate with sulfuric acid in due proportions, it is possible to obtain calcium sulfate, which is the main constituent of gypsum, widely used in the field of medicine and handicrafts. Despite the abundance of raw material for the manufacture of gypsum in industries, the idea of reusing waste as a proposal for the production of this material becomes a significantly attractive alternative, since one of the causation of discussion between managers and society are the generation and final disposal of waste, so the use of eggshells means a reduction in the disposal of these residues with high polluters in landfills.
Calcium oxide, which can be generated by calcination of egg shell residues, is a white solid, low soluble in water at room temperature and generates solutions with high alkalinity, pH around 12.8. So-called lime water is a saturated solution of calcium oxide. In the paint industry CaO is mainly used in the production of lime paint, generally used for painting, also known as whitefall, has been used since antiquity to correct wall imperfections (MORAES et al, 2015). The use of lime paints from the CaO produced by calcination of egg shell residues could ensure cheaper products and safer and environmentally cleaner chemical processes (GIULIO, 2007).
According to everything that has been exposed, the idea of relating the teaching of areas of chemistry with environmental education becomes quite attractive, because this approximation of problems related to inadequate waste disposal and the reuse of waste in order to obtain new materials ends up providing students, who follow the project, the possibility of reflecting on environmental issues in their own community , awakening in the child a greater capacity to evaluate the importance of preserving the environment for the health of the society to which he is inserted. All knowledge acquired in the school can also feed the idea that the student can change the reality of his community in a positive way. The production of materials from egg shell waste can also provide the student and the community with an opportunity for new forms of enterprise and development of cleaner environmental technologies.
The work on the production of materials from egg shell residues was developed at the Federal Institute of Pará (IFPA) Óbidos-PA campus. The main objective of the work was to provide students with the opportunity to discuss environmental issues using chemistry as a tool to reuse waste dumped inappropriately and disorderly in nature, thus minimizing many environmental impacts generated by improper disposal of materials that may be useful as a recycled product.
In a pedagogical panorama, the activities developed at work can emerge as a tool that allows the learning of chemistry concepts in a contextualized way and related to the theme of environmental education, thus providing a theoretical and practical basis so that the student can develop critical and scientific concepts on the theme involved in the project.
The main concepts worked during the development of the research were: environment and environmental pollution, chemical solutions, stocametry, chemical reactions, chemical balance, thermochemistry, environmental education and sustainable development. As much of the content presented was inserted in the curriculum of the 2nd year classes, these were selected for the preparation of the research, totaling a total of 3 classes with approximately 40 students in each.
2. MATERIALS AND METHODS
All elaboration of the work was developed with as main focus the awareness of the environment and the teaching of chemistry as a stimulating tool for the production of technologies that help to ensure the reduction of garbage waste in nature. To this end, an activity program with all students of the institute’s 2nd grade of high school was organized on the IFPA campus of the city of Óbidos-PA, since they are able to train professionals directly connected with the environment area.
First, to start the activities, an information survey was developed, where students were encouraged to research on various environmental-related issues, including existing laws and technologies for recycling materials. For this, teams were formed, in each class, composed of 5 individuals, the purpose of the research was to collect as much information as possible on the subject, and in this way it was possible to trace a relationship between the study of chemistry and the environment. Through the survey, all teams presented a theme related to chemistry and the environment, these themes were put to a vote by the classes. Students from all classes chose and created a common theme, called by the students themselves: “Use of chicken shell waste as a proposal for the production of industrial products at low cost”. From this theme was elaborated a pedagogical project that should meet the needs of theoretical and practical classes relating chemistry and the chosen environmental theme.
2.1 DIDACTIC-PEDAGOGICAL PROJECT
Use of chicken shell waste as a proposal for low-cost industrial product production
2.1.1 OVERALL OBJECTIVE
Use chemical waste reuse processes as a tool for teaching chemistry and environmental education.
2.1.2 SPECIFIC OBJECTIVES
- Encourage the student to understand basic concepts of chemistry that are related to the process of reuse of egg shell residues;
- Promote environmental awareness between school and society;
- Produce an ecological paint and gypsum using as raw material residues of chicken eggshell;
- Production and analysis of calcium oxide yield, produced through calcination of residues of washed eggs;
- Production and analysis of calcium sulfate yield, produced through sulfuric acid reaction and crushed and washed egg shell;
- Use the knowledge used at work to stimulate the learning of basic disciplines, which are related to environmental education, in the various courses offered by the institute.
- Use basic chemistry concepts to promote environmental education.
- Environmental Education
- Chemical solutions
- Chemical kinetics
- Chemical reactions
Classes: All grades of the 2nd technical year integrated to high school
Estimated time: 3 months
- Alcohol 70%
- Distilled water
- Magnetic stirrer
- Sulfuric acid
- PVA Glue
- Watch glass
- Crushed eggshells
The development of the work was elaborated in 3 stages. In the first stage, we sought to conduct a theoretical survey on the subjects related to the theme chosen by the students and environmental chemistry; the second stage consisted of the method of preparing materials by the use of egg shell residues; and the last stage was evaluation with the objective of verifying the students’ learning. Each step is described below:
- Step 1: In this first moment will be raised several issues related to the environment and urban waste, encouraging students to reflect on environmental impacts and laws elaborated by public managers in the municipality and on the planet. After the debate and research done by the students, chemistry classes will be taught relating the selected theme with the discipline, showing the student the importance of knowledge of chemistry to promote waste management and production of materials that help reduce regional and planetary environmental impacts. The final objective of this stage will be to develop in the student a critical, scientific and social spirit on all issues related to the environment.
- Step 2: In this step, students will be divided into groups and encouraged to catalog the amount of garbage and waste chicken eggs that can be collected in their homes and at meal points near their homes in order to be used as raw material in the operation of the work. To encourage collection, groups should distribute in establishments and homes, pamphlets talking about environmental awareness. During the delivery of the pamphlets, each group will also make an oral presentation about the work and its importance in the community. In addition to the pamphlets, containers for collecting eggshells will also be distributed in the community. After collection, students will be taken to the laboratory to manufacture the materials from residues of the chicken eggshell according to the elaborated protocol.
- Waste Preparation And Cleaning
For preparation and cleaning of egg shell residues, the material will first be washed using bleach. After washing the shells, the material will be dried in a greenhouse with temperature measuring 80 ºC, during the drying process the material should be confined in the oven for 24 hours. After these procedures, they will be removed from the inner membrane of the egg shell, followed by the grinding of the shell. At the end of the process, the material will be weighed in analytical balance and the data will be stored for further comparations in yield analyses (RODRIGUES, 2017).
- Calcium oxide production
For calcium oxide production, the eggshells crushed and cleaned will be subjected to the calcination process in muffle for a time of 1h at a temperature of 800ºC.
- Obtaining calcium sulfate (Gypsum)
To obtain calcium sulfate, first a quantity of 200g of eggshell previously treated and crushed will be separated into a beaker. Then, on the sample, 280 ml of 8 Molar sulfuric acid solution will be added, which will be under constant agitation in magnetic stirrer for a time of 30 minutes. After the reaction time has ended, the resulting material will be filtered and taken for drying in a regulated oven at 105ºC for a time of 24 hours.
- Ink preparation
To prepare the paint, 200 g of calcium oxide, produced from the egg shell, and 400 ml of water will be mixed in a container. The mixture will be stirred for 10 minutes and left to rest for another 10 minutes. Subsequently, on the solution should be added 100 ml of PVA glue, the mixture will be stirred again and taken for testing.
- Step 3: Once the final product has been formed, issues related to environmental education, the social role of each person as a citizen and how we can apply scientific knowledge as a tool to reduce environmental impacts in a society will be raised again. This final stage basically has two evaluative moments, the first consists of observing the development of each team, analyzing the performance and resourcefulness of the students in the presentation and explanation of the work during their presentations at the Environment Week event offered by ifpa campus Óbidos-PA. In the second moment of this stage, a theoretical evaluation will be passed to each student individually, where the main content will be based on the practical stages of preparation of the project and its relationship with the topics of chemistry such as: Stochiometry, Chemical Solutions, Chemical Reactions and Chemical Kinetics.
2.1.5 FINAL PRODUCT
- Seminars, at school and in the community, presenting the problems and possible solutions to the trash;
- A sample presented at Environment Week, showing to the whole community the production of ecological paint and gypsum as industrial materials obtained by the use of residues from the eggshell of chickens.
3. RESULTS AND DISCUSSION
In the waste collection stage, the students initially conducted a survey on the amount of waste generated in homes and at commercial points near their homes. The result was that each residence produced approximately 600 g of garbage per day, of which 24g was egg shell waste, and commercial establishments (restaurants and snack bars) generated approximately 4Kg of garbage per day, of which about 800g were egg shell residues. The results of the total collection performed by the students during a week were gathered in Table 1, in the table we can observe that the amount of garbage produced by a commercial establishment is equivalent to approximately a quantity of garbage produced for 7 days of a residence, in this sense the public policies related to selective collection, could begin the incentives for collection with the restaurants and cafeterias of the municipality. According to the survey, 100% of the population, who participated in the work, did not select the garbage, and the organic material was mixed with all kinds of recyclable material or not. At this stage, we can observe that although the media carry out a campaign on the importance of separating garbage, many residents have no habit in separating garbage, most citizens claim that the collection agents make no distinction from the garbage and even the resident having separated the garbage, in the end everything is mixed inside the collection truck , and there is no incentive for selective collection by the city.
Table 1. Amount of waste and egg shell residue produced by each residence and by each commercial establishment.
|Collection site||Average amount of Waste produced in 7 days||Average amount of egg shell residues produced in 7 days|
|Residence||4.8 kg||1.5 kg|
|Restaurant and/or snack bars||28 kg||5.4 kg|
After the information gathering stage, 24 points were selected for collection, 12 residential and 12 commercial. Each group was responsible for collecting and explaining the importance of collection at the selected points, so presentations were made using the brochure entitled: “Environment – The problem of garbage”.
Figure 1. Logo for the event of the week of environment and the image of the groups divided for elaboration of the project.
During the entire presentation of the students in the residences and commercial points, information was passed on about environmental education and environmental problems caused by inadequate disposal of garbage, in addition, plastic containers were distributed in the community for separation and subsequent collection of chicken eggshells. Both residents and employees of the commercial establishments, proposed to participate in the work and to monitor the outcome of the process during the environment meeting that would take place during the event of the week of the environment of the IFPA campus Óbidos-PA. The results of the reuse process also served as a dissecting and encouraging tool for the participation of parents and the community in the event on the environment offered by IFPA in partnership with the Federal University of Western Pará (UFOPA). At the event, the students presented the results and explained the process showing each stage for the production of ecological paint and gypsum, and a small amount of the material produced was distributed among the listeners. At this time, the teacher also participated in the event and evaluated the presentation of the groups at work. It was observed that all students participated during the explanation of the project and also that all explained the chemical and physical processes correctly, showing that the data collection performed by the groups actually served as an instrument for learning chemistry and environmental education.
Figure 2. Image of the groups by separating the collected material and cleaning the crushed eggshells.
PAZ and collaborators (2010) analyzed the teaching-learning process of chemistry of the 2nd grade of high school in some public schools. The data collected by the authors showed that approximately 70% of the students in this series have great difficulty in learning the discipline because they have problems related to calculations, and still approximately 30% have problems related to the lack of practical classes. According to the authors, the methodology used by the teacher is a remarkable reason for this, because it ends up emphasizing the memorization of formulas, and thus, calculations are prioritized and the experimentation and construction of scientific knowledge is devalued, making students have great difficulty in learning the discipline at this stage.
Following the reality and the problem related to chemical calculations, during the work the students were always encouraged to perform all calculations through observations and experiments, for example, for the production of calcium oxide was observed by each group that on average 1Kg of residue from the crushed egg shell, produced, after the calcination process, about 480g of material (calcium oxide) , with these results, it was possible for the students to find the yield of the reaction through the stochiometric relationship between CaCO3 and CaCO3 according to equation 1:
CaCO3(s) Δ CaO(s) + CO2(g) Equation (1)
(Molecular weight CaCO3: 100g) (Molecular Weight CaO: 56g)
Theoretical: (1kg CaCO3) (560g CaO)
Experimental: (Crushed eggshell: 1Kg) (Produced material: 480g)
Theoretically and without taking into account the purity of the material, with approximately 1Kg of egg shell residue (basically composed of CaCO3) it would be possible to obtain approximately 560g of calcined material (composed basically of CaO). Through the information and the results found in the experiment, it was demonstrated by the students that this reaction had a yield of approximately 86%.
In the production of gypsum from the residue of the crushed egg shell, first the groups had to calculate the amount of sulfuric acid needed to prepare 300 ml of a solution with 8 Molar concentration. With the results obtained, the laboratory technician of the institute handling the entire procedure and the students had the opportunity to follow the entire production process of the solution, due to safety issues and lack of personal protection material for the students, this stage was limited only in the observation. The objective of this activity was basically to demonstrate the production of chemical solutions in the laboratory. After the solution was produced, the mixture was made between the egg shell residue and the solution, in this process the students were not provided to the reaction involved and each group had to write the possible equation between the mixture composed basically of CaCO3 (crushed residue) and H2SO4 (Acid Solution). All groups were able to correctly find the equation involved in the process and also correctly balanced it as shown below (equation 2):
CaCO3(s) + H2SO4(aq) CaSO4(s) + H2O(l) + CO2(g) Equação (2)
During the production stage of the material, it was possible to observe that virtually all students wanted to be involved in the project, this demonstrates that experimentation plays a very important role in the construction and encouragement of knowledge for chemistry discipline. The attention deficit during the explanations of each part of the content was minimal and the great difficulty of the relationship of mathematical calculations with discipline were low. It was observed during the work that most students had basic knowledge of mathematics, but a great difficulty in applying the equations in a chemistry problem. It was evident, during the progress of the research, that with observation and experimentation it becomes much more practical and easy for the student to apply the calculations for a proper purpose in a laboratory experiment, in this way the discipline is basically not restricted only in decorative equations and calculations and unattractive.
Many authors fortify the idea of the best learning in chemistry obtained through experimentation, for example, SILVA JÚNIOR (2016) exposes a reflection on experimentation in the teaching of chemistry. For the author, the use of experimentation allows the student to experience real situations that are presented in the concepts of chemistry, and thus the student tends to participate more in the class and at the same time allows him to relate theory with practice. The author adds that practical activities in chemistry have as its purpose to develop students more effectively in the learning process, so it is necessary to create new ways that promote chemistry teaching in an investigative way and motivate students to learn how to elaborate hypotheses, collect and analyze data and structure their own conclusions in order to apply them in the society of which they are part.
SILVA (2016) admits that the learning processes of conceptual and procedural content are enriched through investigative activities, these types of activity, regardless of the environment where they are performed, provide and promote a more active role for students in the development of classes, so the construction of knowledge is much greater through observations and investigations when compared with a purely theoretical class.
In the work developed, approximately 90% of all students involved were able to obtain a score higher than or equal to the school average in the written (theoretical) evaluation. This demonstrates that the use of didactic-pedagogical resources involved in the activities influenced and motivated the teaching-learning process, because the use of chemistry as a tool for the production of materials stimulated the practice and scientific experimentation of the contents involved in the activities. The evaluation was divided into 15 dissertation questions, 5 on the environment and 10 on chemistry covering the contents of chemical solution, chemical kinetics, stocametry and chemical reactions. The main objective of this evaluation stage was to observe whether there was fixation of the theoretical part of the subject by the students, as the vast majority were successful during the written evaluation, it is concluded that the use of the pedagogical resources used served as a tool for teaching the discipline taught. After work, the total average in terms of student grade in the discipline with relationships for previous years, practically increased by 80% and the number of students retained for recovery reached approximately zero.
The work and the survey of information carried out by the students served as a stimulating instrument for the search for knowledge related to the environment, encouraged research on the problem of garbage, developing in the students a critical view about how the current society lives and how much each human being is effectively concerned with this theme.
The data found by the students in the experiment of material manufacturing by the use of residues of chicken eggshell were presented as an excellent method to motivate the teaching learning of chemistry. The idea of demonstrating the importance and purpose of the use of mathematical calculations in the manufacture of materials generated a decrease in the high rates of difficulty of students in relating the use of calculations with chemistry. What may have contributed to this success was to use the calculations for a practical purpose, showing the student that the formulas used are also part of the experiment, and thus the calculations have an objectivity, since they are essential to start and finish the experiment.
The use of the project also ended up encouraging the community participation in the event of the environmental week offered by IFPA, because during the presentation of the work, many residents had the opportunity to expose how they participated for the execution of the project and how the project influenced the point of view of each resident on the theme of the environment and the issue of urban waste.
The final result of the work was satisfactory, because the objective of producing industrial materials by the use of eggshells as a proposal to teach environmental and chemical education was achieved. The results in the written evaluations showed that the concept of content was effectively fixed and understood by the students, thus learning was more significant since it stimulated creativity among students and research as a tool for learning chemistry and the formation of the citizen with environmental and social awareness.
Although the work has helped to raise awareness among part of the community and students, new work on environmental education should be produced and at the same time used for citizen training and science learning as a whole.
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 Master’s degree in Chemistry from the Federal University of Pará.
 PhD student in Education: National University of Rosario.
 Graduating in chemistry degree from the Federal University of Pará.
 Master’s degree in Biosciences from the Federal University of Western Pará.
Submitted: July, 2019.
Approved: July, 2019.