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All Journal Lantanida Journal Jurnal Kartika Kimia Hydrogen: Jurnal Kependidikan Kimia al Kimiya : Jurnal Ilmu Kimia dan Terapan
Mora, Abraham
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Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Education

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DEVELOPMENT OF INSTRUMENT FOR HIGH SCHOOL STUDENTS' READING LITERACY AND NUMERATION ON THERMOCHEMICAL MATERIAL Siswaningsih, Wiwi; Rahmawati, Triannisa; Salsabila, Audria; Zahira, Alfina Dzabillah; Nahadi, Nahadi; Suhanda, Hokcu; Mora, Abraham; Lee, Won Koo
Lantanida Journal Vol 12, No 1 (2024)
Publisher : UIN AR-RANIRY

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22373/lj.v12i1.23427

Abstract

The aim of this research is to produce a minimum competency assessment instrument (MCA) on thermochemical material that meets the test criteria that is suitable for measuring students' reading literacy and numeracy in terms of validity, reliability, level of difficulty and distinguishing power. The research design used is a development and validation design. The participants involved in this research were high school students at one of the high schools in Bandung City as respondents and validators consisting of 3 lecturers and 2 teachers in their fields. The product resulting from this research is the MCA test instrument on thermochemical material which consists of 5 reading literacy questions and 15 numeracy questions. This test instrument was declared valid based on content validity and based on empirical validity, 16 questions were valid and 4 questions were invalid. The reliability test results showed that the reliability value for the objective questions was 0.73, while the reliability value for the description questions was 0.77 and both were declared reliable. The results of the MCA instrument competency level analysis show that students' reading literacy and numeracy competencies are included in the basic category and require special intervention with a refractive index of 1.53 and 1.00.
Pungut Ulang Perak dari Limbah Elektronik Baterai Koin Perak Oksida Menggunakan Pelarut Deep Eutectic Oksalin Fatimah, Soja Siti; Nugraha, Agung Slamet; Mora, Abraham
Jurnal Kartika Kimia Vol 5 No 2 (2022): Jurnal Kartika Kimia
Publisher : Department of Chemistry, Faculty of Sciences and Informatics, University of Jenderal Achmad Yani

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26874/jkk.v5i2.165

Abstract

Silver is a metal that has the highest electrical conductivity, thermal conductivity and reflectivity among all metals and by 2021 the world's silver demand will reach 32,627 tons. To meet the world's silver demand, apart from mining from nature, silver can also be obtained through re-collection of electronic waste using environmentally friendly Deep Eutectic Solvent (DES). The aim of this study was to recover metallic silver from electronic waste of silver oxide coin batteries using oxalin DES leaching method. The research methodology consisted of the steps of synthesizing the eutectic solvent oxalin, characterizing it, and its application to the leaching of silver from the cathode of a silver oxide battery. Silver leaching was carried out by dissolving 0.2 grams of sample with 1:1 oxaline solvent by direct heating for 3 × 8 hours at 500 rpm. The leaching temperature variations were 50, 60, 70, and 80oC and the volume variations of the DES oxalin used were 20, 40, 60, 80, 100, and 125 mL/g. The concentration of leached silver was measured using AAS instrumentation. The results of the synthesis were characterized by FTIR indicating the formation of a new intermolecular interaction, namely the COOH••••Cl interaction. DES oxalin has a density of about 1.2095 g/mL. Based on the results of the optimization of the leaching temperature using 20 mL/g of solvent, the optimum temperature for leaching was found at 60oC with a leaching efficiency of 88.35%. While the results of the volume optimization of the solvent carried out at the optimum temperature, it was found that the optimum volume of the solvent used was 80 mL/g of sample with a leaching efficiency of 94.23%. Based on these results, it can be seen that oxaline has the potential to be used as a solvent in the treatment of used silver oxide battery waste.
Conducting Polymers for Wearable Sensors: A Bibliometric Analysis Using VOSviewer Mora, Abraham; Aziz, Arrizal Abdul
Hydrogen: Jurnal Kependidikan Kimia Vol 12, No 1 (2024): February 2024
Publisher : Universitas Pendidikan Mandalika

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33394/hjkk.v12i1.10435

Abstract

The objective of this study is to conduct a bibliometric analysis using VOSviewer on the research progress of the conducting polymer for wearable sensors topic. Data was extracted from the Dimensions database from 2014 to August 2023. 268 Dimensions articles were relevant to the keywords. The title and abstract from the metadata were employed to be analyzed for co-occurrence using VOSviewer. As a result, 9544 terms were obtained through the search method, but only 184 met the threshold of 10 minimum occurrences in all retrieved articles and were selected for further analysis. There was a consistent upward trend in publication numbers between 2014 to August 2023. Based on the network visualization of keyword co-occurrence, it evidenced six clusters that group all specific keywords based on the common themes. The most recent keywords (occurred between 2021 and 2022) included conductive hydrogel, polymer hydrogel, flexible sensor, MXene, strain sensor, and stretchable strain sensor. Based on this study, it is suggested to discover more about conducting and flexible hydrogel materials and the possibilities to enhance the electrical and mechanical properties of conducting polymers by introducing MXene. The materials are viewed for applications such as flexible strain sensors and other wearable sensors.
Silver Leaching from Printed Circuit Board Using Deep Eutectic Solvent-Oxaline, Maline, and Succiline Fatimah, Soja Siti; Mora, Abraham; Sumarna, Omay; Ramdaniah, Hudaifatul A. N
al Kimiya: Jurnal Ilmu Kimia dan Terapan Vol. 12 No. 1 (2025): June 2025
Publisher : Department of Chemistry, Faculty of Science and Technology, UIN Sunan Gunung Djati Bandung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15575/ak.v12i1.46024

Abstract

The exponential growth in printed circuit boards (PCBs) waste, presents an urgent environmental and economic challenge. PCBs contain silver which has a high potential economic value. The high production of waste and the potential economic value make it important to recycle PCB waste. Recycling can be conducted by leaching silver using Deep Eutectic Solvent (DES). DES is environmentally friendly and able to form complexes with various types of metals. This research aims to study the effect of the HBD carbon chain length of oxalic acid, malonic acid, and succinic acid from choline chloride-based eutectic solvents (DES) on the efficiency of leaching silver from Printed Circuit Board (PCB) waste. Optimization of the solid/liquid ratio, time, and temperature is carried out to obtain optimum leaching conditions. The synthesis results show that DES oxaline 2:1, malin 1:1, and succilin 2:1 have good stability, forming a colorless, clear, and viscous solution. FTIR analysis shows a shift in the wave number of the -OH group due to hydrogen bond interactions between HBA and HBD molecules in the formation of DES. The leaching yield of DES against standard silver oxide was measured using AAS. DES oxaline 2:1 has the greatest efficiency compared to other DES variations. The results of optimizing standard silver leaching with DES oxaline showed that the S/L ratio was 40 mg/mL, with a time of 18 hours, at a temperature of 60°C which resulted in a recovery percentage of 90.90%, while for the PCB waste sample yielded an efficiency of 99.38%. The eutectic solvent oxaline has the potential to be an environmentally friendly solvent that is efficient in leaching silver from PCB electronic waste.
DEVELOPMENT OF INSTRUMENT FOR HIGH SCHOOL STUDENTS' READING LITERACY AND NUMERATION ON THERMOCHEMICAL MATERIAL Siswaningsih, Wiwi; Rahmawati, Triannisa; Salsabila, Audria; Zahira, Alfina Dzabillah; Nahadi, Nahadi; Suhanda, Hokcu; Mora, Abraham; Lee, Won Koo
Lantanida Journal Vol 12 No 1 (2024)
Publisher : UIN AR-RANIRY

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22373/lj.v12i1.23427

Abstract

The aim of this research is to produce a minimum competency assessment instrument (MCA) on thermochemical material that meets the test criteria that is suitable for measuring students' reading literacy and numeracy in terms of validity, reliability, level of difficulty and distinguishing power. The research design used is a development and validation design. The participants involved in this research were high school students at one of the high schools in Bandung City as respondents and validators consisting of 3 lecturers and 2 teachers in their fields. The product resulting from this research is the MCA test instrument on thermochemical material which consists of 5 reading literacy questions and 15 numeracy questions. This test instrument was declared valid based on content validity and based on empirical validity, 16 questions were valid and 4 questions were invalid. The reliability test results showed that the reliability value for the objective questions was 0.73, while the reliability value for the description questions was 0.77 and both were declared reliable. The results of the MCA instrument competency level analysis show that students' reading literacy and numeracy competencies are included in the basic category and require special intervention with a refractive index of 1.53 and 1.00.
Conducting Polymers for Wearable Sensors: A Bibliometric Analysis Using VOSviewer Mora, Abraham; Aziz, Arrizal Abdul
Hydrogen: Jurnal Kependidikan Kimia Vol. 12 No. 1 (2024): February 2024
Publisher : Universitas Pendidikan Mandalika

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33394/hjkk.v12i1.10435

Abstract

The objective of this study is to conduct a bibliometric analysis using VOSviewer on the research progress of the conducting polymer for wearable sensors topic. Data was extracted from the Dimensions database from 2014 to August 2023. 268 Dimensions articles were relevant to the keywords. The title and abstract from the metadata were employed to be analyzed for co-occurrence using VOSviewer. As a result, 9544 terms were obtained through the search method, but only 184 met the threshold of 10 minimum occurrences in all retrieved articles and were selected for further analysis. There was a consistent upward trend in publication numbers between 2014 to August 2023. Based on the network visualization of keyword co-occurrence, it evidenced six clusters that group all specific keywords based on the common themes. The most recent keywords (occurred between 2021 and 2022) included conductive hydrogel, polymer hydrogel, flexible sensor, MXene, strain sensor, and stretchable strain sensor. Based on this study, it is suggested to discover more about conducting and flexible hydrogel materials and the possibilities to enhance the electrical and mechanical properties of conducting polymers by introducing MXene. The materials are viewed for applications such as flexible strain sensors and other wearable sensors.
Co-Authors Aziz, Arrizal Abdul Hokcu Suhanda Lee, Won Koo Nahadi Nugraha, Agung Slamet Omay Sumarna Ramdaniah, Hudaifatul A. N Salsabila, Audria Soja Siti Fatimah Triannisa Rahmawati, Triannisa Wiwi Siswaningsih Zahira, Alfina Dzabillah