Electrolysis Concepts Research Articles

The Development of Chemical Representations-Oriented Virtual Laboratory for Teaching Electrolysis in Chemistry Classes

This study aimed to describe the development of a chemical representation-oriented virtual laboratory. It produced a learning media application which could be used in electrolysis study materials. The study described the analysis phase and the design and development phase. It also analyzed the results of limited tests towards the product. The study showed that the virtual laboratory features a colorful, attractive design and interactivity. The virtual laboratory can be potentially used as a learning media in chemistry learning on electrolysis concepts.
 Keywords: chemical, virtual laboratory, electrolysis

(Invited) Leveraging Magnetohydrodynamic Mechanisms for Stable and Efficient Microgravity Electrolysis

Water electrolysis is the fundamental chemical process for oxygen and hydrogen production in space. It is widely employed in modern environmental control and life support systems, propulsion technologies, and high-density energy storage devices. Furthermore, future interplanetary missions are likely to employ water as a commodity acquired and processed by In Situ Resource Utilization (ISRU) methodologies to produce propellants, thereby reducing vehicle launch mass.The absence of buoyancy results in major technical challenges for the operation of electrolytic cells in low gravity. The need to detach and collect oxygen and hydrogen bubbles has been traditionally addressed by means of forced water recirculation loops. However, this leads to complex, inefficient, and unreliable liquid management devices composed of multiple elements and moving parts. Two distinct magnetohydrodynamic (MHD) mechanisms may instead be employed to induce phase separation: diamagnetic, and Lorentz forces. The former arises in the presence of strong, inhomogeneous magnetic fields and results in a magnetic buoyancy effect. The latter is a consequence of the imposition of a magnetic field to the current generated between two electrodes. Both approaches can potentially lead to a new generation of electrolytic cells with minimum or no moving parts, hence enabling the human deep space operations with minimum mass and power penalties.Dedicated microgravity experiments are required to study these novel magnetically enhanced electrolysis concepts. This presentation introduces the fundamentals of both methods and discusses the experimental design and results from several experimental campaigns at ZARM’s drop tower and Blue Origin’s New Shepard. The performance of representative electrolytic cells subject to different MHD regimes is addressed from an electrochemical and fluid dynamic perspectives. It is demonstrated that the MHD force effectively detaches and collects gas bubbles in microgravity while increasing the current density and improving the stability of the electrolytic cell. Ultimately, this opens the door for the development of highly-efficient space electrolytic cells with applications to human and robotic space exploration.

Video-Based Teaching on Electrolysis Using Simple Copper Media to Vocational School Students

Abstract: The purpose of this study was to present learning the concept of electrolysis using simple copper media to vocational high school students in grade 3. This research was conducted by making a sample of well water with CuCl₂ solution which has a concentration of 1g / L and voltage variation (1.5; 3; 4.5; 6,0; 7.5; and 9,0 V). The test was carried out by electrolysis and water quality tests consisting of solute level testing, water pH test, and water temperature test. This research was also conducted by providing pre-test questions, learning videos, and post-tests. The results showed that the most effective electrolysis method occurred in variations with a voltage of 9V. This is indicated by the value of the decrease in concentration and the increase in mass of solutes after electrolysis. Meanwhile, the test results of vocational high school students show that video-based teaching can improve students 'understanding, as indicated by the students' post-test scores that are higher than the pretest scores. This research is expected to assist in the selection of instructional media for students and to find out which electrolysis method is effective for reducing Cu levels. Keywords: CuCl₂, electrolysis, learning media, simple copper.

Alkaline Electrochemical Reduction of a Magnesium Ferrospinel into Metallic Iron for the Valorisation of Magnetite-Based Metallurgical Waste

The electrochemical reduction of iron oxides in alkaline media arises as a novel approach for ironmaking and iron-rich waste valorisation. Strong advantages and attractive aspects of alkaline electroreduction include lower electric energy consumption, absence of CO2 emissions, and non-polluting valuable by-products such as H2 and O2. Another potential advantage originates from the compatibility of this concept with intermittent renewable energies. However, to bring this technology to a competitive level, especially compared to the traditional steelmaking, innovative approaches and developments in materials processing and their appropriate integration into the electrolysis process are required. This research work explores the prospects for electrochemical reduction of a magnesium-containing ferrospinel, as a potential component in iron-containing wastes. The experimental approach considers bulk cathode- and suspension-based electrolysis concepts, which allow reaching 55% and 20% Faradaic efficiencies of the reduction to metallic iron, respectively. The effects imposed by the magnesium presence on the electroreduction kinetics, phase composition and morphology of the electroreduction products are evaluated and discussed. The obtained results open new perspectives for the recovery of metallurgical residues with low magnesium impurities content.

Kesulitan Siswa Kelas XII MIA SMA Negeri Di Kota Palangka Raya Tahun Ajaran 2018/2019 Dalam Memahami Konsep Sel Elektrolisis Yang Ditelusuri Menggunakan Instrumen Two Tier Multiple Choiche

Sel elektrolisis merupakan ilmu yang mempelajari proses perubahan energi listrik menjadi energi kimia. Sel elektrolisis khususnya sangat berkaitan dengan kehidupan sehari-hari sehingga menjadi salah satu hal penting dalam bidang kimia, namun konsep ini sendiri memiliki tingkat keabstrakan yang cukup tinggi. Keabstrakan ini merupakan salah satu penyebab siswa mengalami kesulitan dalam memahami konsep kimia. Penelitian ini bertujuan untuk mendeskripsikan kesulitan siswa kelas XII MIA SMA Negeri di kota Palangka Raya tahun ajaran 2018/2019 dalam memahami konsep sel elektrolisis yang ditelusuri menggunakan instrumen two tier multiple choice. Subjek penelitian ini adalah siswa kelas XII MIA yang berjumlah 265 siswa. Penelitian ini dilaksanakan pada semester genap tahun ajaran 2018/2019. Data kesulitan siswa dijaring menggunakan Tes Pemahaman Konsep Sel Elektrolisis (TPKSE) dan dilakukan wawancara terhadap siswa yang mengalami kesulitan. Data yang telah diperoleh kemudian dianalisis secara deskriptif. Hasil Penelitian menunjukkan bahwa presentase jumlah siswa yang mengalami kesulitan dalam memahami konsep elektrolisis sebesar 68,39%.

Enhancing students' HOTS in laboratory educational activity by using concept map as an alternative assessment tool

Educational transformation in the 21st century demands in-depth knowledge and understanding in order to promote the development of higher-order thinking skills (HOTS). However, the most commonly reported problem with respect to developing a knowledge of chemistry is poor mastery of basic concepts. Chemistry laboratory educational activities are shown to be less effective in developing an optimum conceptual understanding and HOTS among students. One factor is a lack of effective assessment and evaluation tools. Therefore, the primary focus of this study is to explore concept maps as an assessment tool in order to move students' thinking skills to a higher level during laboratory learning activities. An embedded mixed method design is used in this study, which has also employed a pre-experimental research design. This design triangulates quantitative and qualitative data, which are combined to strengthen the findings. A low-directed concept mapping technique, convergence scoring method, and pre-post laboratory concept map were used in this study. An electrolysis HOTS test was used as the research instrument in order to measure the level of student achievement with respect to high-level questions. In addition, the thought process that is involved when students construct concept maps has been explored and studied in detail by utilising a think-aloud protocol. Results showed a positive development towards understanding and higher level thinking skills in students with respect to electrolysis concepts learned through chemistry laboratory activities. An investigation of the students' thinking processes showed that high-achieving students were more capable of giving a content-based explanation of electrolysis and engaged in monitoring activities more often while building a concept map. Nonetheless, all categories of students managed to show a positive increase in the activities of explanation and monitoring during the construction of concept maps after they were exposed to the assessment tool in the laboratory learning activities. In conclusion, the assessment activity using concept maps in laboratory learning activities has a positive impact on students' understanding and stimulates students to increase their HOTS.

Teaching Electrolysis in a way that Enhances Problem Solving, Analytical and Communicative Skills

Problem solving is central in chemical education. In order to succeed as a chemistry student or professionally as a chemist it is highly crucial to develop skills that enhance problem solving. Prioritizing the development of problem solving a lesson on electrolysis was planned for 11th graders. This article presents significant teaching and learning methods that according to research enhance problem solving and other related skills. Additionally the article presents successful applications of these methods into teaching electrolysis concepts. The methods introduced are solving problems cooperatively in groups, solving problems with students rather than for students, the use of animations and provoking class participation and discussion.

Polygeneration of SNG, heat and power based on biomass gasification and water electrolysis—concepts and their assessment

The gasification of biomass and the subsequent conversion to electric power, heat, or synthetic natural gas (SNG) offers the possibility to produce different products in one process under minimizing potential losses. In a so called polygeneration approach, the operation of such a process may be linked to changing energy market situations to improve the economic viability. The integration of water electrolysis for hydrogen production enables the process to provide positive as well as negative controlling power; i.e. it can provide system service and contribute to the stability to the electricity grid. Against this background, the aim of this paper is the technical, economic and environmental analysis of a polygeneration approach based on biomass gasification processes for the provision of SNG, heat and power taking the current electricity spot market into consideration. Therefore, several processes schemes are developed and analysed in terms of process efficiency (exergetic efficiency), economic viability (SNG production costs) as well as environmental performance (specific greenhouse gas emissions). For comparison, a biogas-based polygeneration approach for the production of biomethane, heat and power is analysed as well. In case of an operating mode optimised for SNG production, the exergetic efficiency results between 65.4 and 67.2 % for the gasification-based processes and 55.6 to 63.3 % for the biogas-based processes. If primarily electric power is provided in case of high spot market prices, the operation mode is optimised for power production; this results in significantly lower exergetic efficiencies of 48.0 to 44.9 % for the gasification-based processes and 38.0 to 41.2 % for the biogas-based processes. The production costs are calculated depending on the full load operating hours for maximizing SNG production and maximised power production, respectively. The results show a clear dependency of SNG production costs from the operating hours for all processes. The GHG emissions for maximum SNG production range between 43.4 and 95.1 gCO2-eq/kWhMethane. If more power is produced, the emissions rise to values between 55.4 and 127.6 gCO2-eq/kWhMethane. Lower emissions can be achieved by SNG production via gasification than via biogas.

HIGH SCHOOL STUDENTS’ PROFICIENCY AND CONFIDENCE LEVELS IN DISPLAYING THEIR UNDERSTANDING OF BASIC ELECTROLYSIS CONCEPTS

This study was conducted with 330 Form 4 (grade 10) students (aged 15 – 16 years) who were involved in a course of instruction on electrolysis concepts. The main purposes of this study were (1) to assess high school chemistry students’ understanding of 19 major principles of electrolysis using a recently developed 2-tier multiple-choice diagnostic instrument, the Electrolysis Diagnostic Instrument (EDI), and (2) to assess students’ confidence levels in displaying their knowledge and understanding of these electrolysis concepts. Analysis of students’ responses to the EDI showed that they displayed very limited understanding of the electrolytic processes involving molten compounds and aqueous solutions of compounds, with a mean score of 6.82 (out of a possible maximum of 17). Students were found to possess content knowledge about several electrolysis processes but did not provide suitable explanations for the changes that had occurred, with less than 45 % of students displaying scientifically acceptable understandings about electrolysis. In addition, students displayed limited confidence about making the correct selections for the items; yet, in 16 of the 17 items, the percentage of students who were confident that they had selected the correct answer to an item was higher than the actual percentage of students who correctly answered the corresponding item. The findings suggest several implications for classroom instruction on the electrolysis topic that need to be addressed in order to facilitate better understanding by students of electrolysis concepts.

Some Design Considerations for Electrolytic Silver Recovery from Photographic Fixing Baths

The basic concept of electrolysis and the principle reactions at the electrodes of silver recovery from fixing baths are presented. Some design considerations for a recovery cell and for the choice of an appropriate dc power supply are given. The voltage regulation and feedback controls are described and the requisite instrumentation used in their application stipulated.