The Effect of Electrode Type and Electrode Surface Area

Study Case The Effect of Electrode Type and Electrode Surface Area on Electrical Voltage in Coal Stockpile Waste Michael Kurniawan (2018123456) University of Cincinnati, 2600 Clifton Ave, Cincinnati, OH 45221, United States kurniaml@mail.uc.edu Abstract Liquid waste from coal stockpiles contains dissolved ions that can conduct electrical current, making it useful as an electrolyte medium. When two different metal electrodes are placed in this solution, electrical voltage can be generated. This study aims to evaluate the electrical voltage generated from coal stockpile waste through a combination of electrode types and to analyze the effect of different electrode surface areas on electrical voltage. The method used was an experiment with a combination of electrodes (Cu-Zn), (Zn-Al), and (Cu-Al), and electrode surface areas of 1 cm × 10 cm, 3 cm × 10 cm, and 5 cm × 10 cm, respectively. The data were analyzed descriptively, followed by a two-factor F test to examine the effect of electrode type and electrode surface area combinations, as well as a Least Significant Difference (LSD) analysis to determine the differences between treatments. The results showed that the Cu-Zn electrode combination with a surface area of 5 cm × 10 cm produced the highest voltage of 1.02 volts. The two-factor F test indicated that both the type of electrode and the electrode surface area had a significant effect on the electrical voltage produced. Keywords: Electrode Combination, Surface Area, Electrical Voltage, Coal Stockpile INTRODUCTION The United States has abundant natural resources, one of which is coal, which is found in the states of Wyoming and West Virginia. Coal is mostly used for steam power plants (PLTU) and other industries [1]. Coal is a combustible sedimentary rock, formed from plant remains that were deposited over hundreds of years through humification, geological, and chemical processes [2]. MICHAEL KURNIAWAN 1 Study Case The coal mining process not only provides economic benefits but also has an environmental impact. One of these is the increase in solid and liquid waste from stockpiles, which are classified as hazardous waste and require special handling [3]. Mining activities that have the potential to harm the environment include excavation, transportation, processing, washing, and temporary storage of coal in stockpiles [4]. Waste can be solid, liquid, or gas. With technological advances, waste that was previously harmful can be reprocessed into products of economic value [5]. Coal stockpile waste is liquid waste that comes from the temporary storage of coal before it is transported to its final destination. This waste contains suspended solids and dissolved ions that are capable of conducting electricity [6]. An electrolyte solution is a solution that contains ions that can generate an electric current. Electrolyte solutions can be strong or weak electrolytes. Strong electrolytes have completely dissociated ions, characterized by the appearance of many gas bubbles, resulting in a large electric current, while weak electrolytes produce a smaller electric current with few gas bubbles [7]. Electrical energy is very important in everyday life, used in industry, the commercial sector, and household electronic devices. The amount of electrical energy depends on voltage, current, and time. Alternative energy, such as voltaic cells, can be an additional source of energy from materials that are easily obtained and maximally utilized through human intervention [8]. A voltaic cell, or galvanic cell, is an electrochemical cell that produces electric current through oxidation-reduction reactions. Oxidation occurs at the anode (negative pole) and reduction at the cathode (positive pole), with an electrolyte solution as the electrical conductor [9]. Electrodes are conductors connected to an electrolyte solution and can be metals (copper, zinc, aluminum) or non-metallic conductors such as graphite [10]. This study utilizes coal stockpile waste as an electrolyte medium to generate electrical voltage using a combination of different anodes and cathodes. RESEARCH METHODOLOGY Tools and Materials The tools used include: digital multitester, 250 mL beaker, alligator clips, ruler, scissors, and copper (Cu), zinc (Zn), and aluminum (Al) metal plates. The material used is liquid waste from coal stockpiles. MICHAEL KURNIAWAN 2 Study Case Research Method This research used an experimental method by combining electrode types and electrode surface areas in coal stockpile waste electrolyte media. The electrical voltage produced was measured using a digital multitester. Research Design The research design used a two-factor completely randomized design (CRD). The first factor was the combination of electrode types: Copper–Zinc (Cu-Zn), Zinc– Aluminum (Zn-Al), and Copper–Aluminum (Cu-Al). The second factor was the electrode surface area: 1 cm × 10 cm, 3 cm × 10 cm, and 5 cm × 10 cm. The research design is presented in Table 1. Table 1. RAL Research Design Note: J1 = Cu-Zn, J2 = Zn-Al, J3 = Cu-Al; L1 = 1×10 cm, L2 = 3×10 cm, L3 = 5×10 cm. Figure 1. Research Flow Chart Research Procedure 200 mL of coal stockpile waste was poured into a 250 mL beaker. Zinc (Zn) and copper (Cu) plates were placed in the solution, where the Zn plate acted as the anode and the Cu plate as the cathode. The electrodes are connected using alligator clips; the end of the Cu electrode cable is connected to the positive pole of the digital multitester, while the end of the Zn electrode cable is connected to the negative pole (Figure 2). The MICHAEL KURNIAWAN 3 Study Case electrical voltage is measured and recorded. This step is repeated for all combinations of electrode types and electrode surface areas. Figure 2. Electrical Voltage Measurement Scheme Data Analysis The data were analyzed descriptively, then a two-factor F test was performed to see the effect of the combination of electrode type and electrode surface area on electrical voltage. If the significance value was <0.05, the treatment was considered to have a significant effect. Differences between treatments were further analyzed using the Least Significant Difference (LSD). RESULTS AND DISCUSSION The results of electrical voltage measurements from combinations of Cu-Zn, Zn-Al, and Cu-Al electrode types with surface areas of 1×10 cm, 3×10 cm, and 5×10 cm in coal stockpile waste electrolyte media are presented in Figure 3. Figure 3. Electrical Voltage Measurement Results MICHAEL KURNIAWAN 4 Study Case It can be seen that the electrode surface area is directly proportional to the electrical voltage produced. The larger the electrode area, the more interaction between the liquid waste electrolyte medium and the electrode, so that the oxidation-reduction reaction (release and acceptance of electrons by the anode and cathode) occurs more intensely, producing higher electrical voltage. This is in accordance with Satriady et al. [1], who stated that a larger electrode surface area provides more active material to accommodate electrons, increasing the electrical voltage through electrochemical reactions. Figure 3 shows that the Copper–Zinc (Cu-Zn) electrode combination produces the highest electrical voltage compared to the Zinc–Aluminum (Zn-Al) and Copper– Aluminum (Cu-Al) combinations. This is because zinc (Zn) as an anode has a greater reduction potential than aluminum (Al), making the Cu-Zn combination most effective for generating electrical voltage in coal stockpile waste electrolyte media. This finding is in line with Nuriskasari [2], who reported that the Cu-Zn electrode combination provides higher electrical voltage. In addition, the combination of electrode type and electrode surface area both affect the electrical voltage. This is supported by Halil [3], who states that the electrical voltage increases linearly with the increase in electrode surface area. An analysis of variance (two-factor F test) was performed using SPSS Statistics Version 22 to test the effect of both factors on electrical voltage, with the results presented in Table 2 and Table 3. Table 2. Number of Data Entered Description: • Electrode type combination (Type): 1 = Cu-Zn, 2 = Zn-Al, 3 = Cu-Al. • Electrode surface area (Area): 1 = 1×10 cm, 2 = 3×10 cm, 3 = 5×10 cm. MICHAEL KURNIAWAN 5 Study Case From Table 2, each combination of electrode type and surface area has 9 observation data. To determine the difference in the effect of treatment on electrical voltage, a two-factor analysis of variance (F test) was performed, the results of which are presented in Table 3. Table 3. Analysis of Variance (Two-Way ANOVA) Table 4. Least Significant Difference (LSD) Analysis Between Electrode Type Combinations Table 5. Least Significant Difference (LSD) Analysis Between Electrode Surface Areas MICHAEL KURNIAWAN 6 Study Case CONCLUSION The electrical voltage generated by coal stockpile liquid waste through the voltaic cell method with a combination of electrode types (Cu-Zn, Zn-Al, and Cu-Al) and electrode surface areas (1×10 cm, 3×10 cm, and 5×10 cm) shows a significant effect (sig < 0.05). The combination of Cu-Zn electrodes and a surface area of 5×10 cm produced the highest electrical voltage, indicating that both factors—electrode type and surface area—significantly influence electrical voltage performance. REFERENCE MICHAEL KURNIAWAN 7