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Effect of Annealing and Etching Times on Anatase TiO2 Hollow Sphere Rakhman, Khusna Arif; Aprilita, Nurul Hidayat; Kartini, Indriana
Molekul Vol 18 No 2 (2023)
Publisher : Universitas Jenderal Soedirman

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20884/1.jm.2023.18.2.7480

The development of high-efficiency photocatalysts plays an important role in the application of solar energy conversion. Titanium dioxide (TiO2) with an anatase crystalline phase is well-known as semiconductor thin layers for solar cells. This work has constructed a novel TiO2 hollow sphere (HST) in a 2-step synthesis. The first step is coating the SiO2 template with TiO2 to build a core-shell of SiO2@TiO2 (CSST). The second step is etching via sonication to elute the SiO2 from CSST and construct the HST. The annealing of CSST for 1 to 6 hours and etching for 1 to 7 hours has resulted in the HST with different crystallite sizes and microstrains. The HST of ~90 nm has been fabricated with crystallite size of 9.53 to 20.54 nm and microstrain from 0.34 to 3.42. It was found that the optimum crystallite size and microstrain of HST obtained via annealing the CSST for 2 hours and etching for 5 hours has the best photooxidation of I- under UV irradiation. The optimum crystallite size and microstrain of HST via annealing and etching times can be recommended for the future of solar cell fabrication and applications.

PENGARUH MODEL PROBLEM BASED LEARNING (PBL) TERHADAP HASIL BELAJAR DAN MOTIVASI SISWA KELAS X MAS AL- MUNAWWARAH LOLEOJAYA PADA MATERI IKATAN KIMIA Ajudin, Nurbani; Sugrah, Nurfatimah; Jayali, Ahmad Muchin; Mustafa, Linda Kurnia; Rakhman, Khusna Arif
Jurnal Pendidikan Kimia Unkhair (JPKU) Vol 4, No 2 (2024): Jurnal Pendidikan Kimia Unkhair (JPKU)
Publisher : Universitas Khairun

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33387/jpku.v4i2.9272

AbstrakPenelitian ini dilakukan dengan tujuan untuk pengaruh model problem based learnig terhadap hasil belajar dan motivasi siswa kelas X Mas Al-munawwarah pada materi ikatan kimia. Jenis penelitianÂ ini adalah penelitian eksperimen dengan desain penelitian yaitu per eksperimental one gorup pritest-postest ,lembaran angket dan respon siswa dengan jumlah sampel yang digunakan 16 siswa. Berdasarkan analisis data, dapat disimpulkan bahwa pengaru model Â PBL terhadapa hasil belajar dan motivasi siswa dapat meningkatkan hasil belajar siswa dengan interpretasi normal. Hal ini sesuai dengan hasil uji hipotesis menggunakan SPSS 21,0 dengan uji pired sample t test. Dapat disimpulkan bahwa pengaru model PBL terhadap hasil belajar dan motivasi siswa dapat meningkatkan hasil belajar dan motivasi tetapi tidak ada hubungan hasil belajar dan motivasi. diperoleh nilai sign sebesar 0,001 (P) 0,05 maka Ho ditolak dan Ha diterima. diperoleh mean rank atau rata-rata penigkatannya sebesar 20,06 dengan interpretasi rendah.Â AbstractStudi This was done with the aim of determining the influence of the problem based learnig model on the learnig outcomes and motivation of class X Mas AL-Munawwarah students on chemical boding material. This type of research is experimental research with a researchÂ desing, namely per experimental one group test-posttest, questionnaire sheets and student responses. with a total sample of 16 students. Based on data analysis, it can be concluded that the influence of the PBL model on student learning outcomes and motivation can improve student learning outcomes with normal interpretation. This is in accordance with the results of hypothesis testing using SPSS 21.0 with the Experimental One Groups test. It can be concluded that the influence of the PBL model on student learning outcomes and motivation can improve learning outcomes and motivation but there is no relationship between learning outcomes and motivation. obtained a sign value of 0.001 (P) 0.05, then Ho is rejected and Ha is accepted. The mean rank or average increase was 20.06 with a low interpretation.

PENGARUH MODEL PROBLEM BASED LEARNING (PBL) TERHADAP HASIL BELAJAR DAN MOTIVASI SISWA KELAS X MAS AL- MUNAWWARAH LOLEOJAYA PADA MATERI IKATAN KIMIA Ajudin, Nurbani; Sugrah, Nurfatimah; Jayali, Ahmad Muchin; Mustafa, Linda Kurnia; Rakhman, Khusna Arif
Jurnal Pendidikan Kimia Unkhair (JPKU) Vol 4, No 2 (2024): Jurnal Pendidikan Kimia Unkhair (JPKU)
Publisher : Universitas Khairun

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33387/jpku.v4i2.9272

AbstrakPenelitian ini dilakukan dengan tujuan untuk pengaruh model problem based learnig terhadap hasil belajar dan motivasi siswa kelas X Mas Al-munawwarah pada materi ikatan kimia. Jenis penelitianÂ ini adalah penelitian eksperimen dengan desain penelitian yaitu per eksperimental one gorup pritest-postest ,lembaran angket dan respon siswa dengan jumlah sampel yang digunakan 16 siswa. Berdasarkan analisis data, dapat disimpulkan bahwa pengaru model Â PBL terhadapa hasil belajar dan motivasi siswa dapat meningkatkan hasil belajar siswa dengan interpretasi normal. Hal ini sesuai dengan hasil uji hipotesis menggunakan SPSS 21,0 dengan uji pired sample t test. Dapat disimpulkan bahwa pengaru model PBL terhadap hasil belajar dan motivasi siswa dapat meningkatkan hasil belajar dan motivasi tetapi tidak ada hubungan hasil belajar dan motivasi. diperoleh nilai sign sebesar 0,001 (P) 0,05 maka Ho ditolak dan Ha diterima. diperoleh mean rank atau rata-rata penigkatannya sebesar 20,06 dengan interpretasi rendah.Â AbstractStudi This was done with the aim of determining the influence of the problem based learnig model on the learnig outcomes and motivation of class X Mas AL-Munawwarah students on chemical boding material. This type of research is experimental research with a researchÂ desing, namely per experimental one group test-posttest, questionnaire sheets and student responses. with a total sample of 16 students. Based on data analysis, it can be concluded that the influence of the PBL model on student learning outcomes and motivation can improve student learning outcomes with normal interpretation. This is in accordance with the results of hypothesis testing using SPSS 21.0 with the Experimental One Groups test. It can be concluded that the influence of the PBL model on student learning outcomes and motivation can improve learning outcomes and motivation but there is no relationship between learning outcomes and motivation. obtained a sign value of 0.001 (P) 0.05, then Ho is rejected and Ha is accepted. The mean rank or average increase was 20.06 with a low interpretation.

DENTIFIKASI KESULITAN BELAJAR KIMIA SISWA KELAS X MADRASAH ALIYAH ALKHAIRAAT SIDANGOLI PADA MATERI STRUKTUR ATOM Hud, Rifki; Liestianty, Deasy; Rakhman, Khusna Arif; Sugrah, Nurfatimah; Cipta, Indra; Mustafa, Linda Kurnia
Jurnal Pendidikan Kimia Unkhair (JPKU) Vol 4, No 1 (2024): Jurnal Pendidikan Kimia Unkhair (JPKU)
Publisher : Universitas Khairun

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33387/jpku.v4i1.8408

Â Informasi JurnalÂ Kata Kunci: Â Â Â Â Â Â Â Â Â Â Â Â Â Â Kesulitan Belajar, Struktur AtomAbstrakPenelitian ini dilakukan untuk mengetahui kesulitan belajar siswa dalam mempelajari materi Struktur Atom, dan faktor-faktor yang mempengaruhinya. Jenis penelitian ini adalah penelitian Deskriptif kuantitatif. Populasi dalam penelitian ini adalah semua siswa kelas X Madrasah Aliyah Alkhairaat Sidangoli yang berjumlah 17 orang. Teknik pengambilan sampel adalah sampel jenuh. Teknik pengumpulan data dalam penelitian ini adalah teknik tes soal 11 item dan 15 item angket. Teknik analisis data adalah analisis kuantitatif. Hasil penelitian menunjukan bahwa kesulitan belajar siswa kelas X Madrasah Aliyah Alkhairaat Sidangoli pada Struktur Atom berada dalam kategori sangat tinggi dengan persentase rata-rata 90% dari 17 siswa yang dijadikan sampel. Faktor yang paling menentukan kesulitan belajar adalah faktor internal pada aspek intelegensi dengan persentase 82% pada kriteria sangat Tinggi dan faktor eksternal pada aspek motivasi guru dengan persentase 65% pada kriteria Tinggi..Â Â Â Â Keyword:Learning Difficulties, Atomic StructureAbstractThis research was conducted to determine students' learning difficulties in studying Atomic Structure material, and the factors that influence it. This type of research is quantitative descriptive research. The population in this study were all 17 class X students of Madrasah Aliyah Alkhairaat Sidangoli. The sampling technique is a saturated sample. The data collection technique in this research is an 11 item test technique and a 15 item questionnaire. The data analysis technique is quantitative analysis. The results of the research show that the learning difficulties of class The factors that most determine learning difficulties are internal factors in the intelligence aspect with a percentage of 82% in the very High criteria and external factors in the teacher motivation aspect with a percentage of 65% in the High criteria.Â

Pengembangan Modul Ajar Berbasis Stem (Science, Technology, Engineering And Mathematics) Pada Materi Elektrolit Dan Non Elektrolit di SMA Negeri 7 Kepulauan Sula Lek, Hajija; -, Muliadi; Ibrahim, Fitriana; Rakhman, Khusna Arif; Zam, Zulkifli Zam
Jurnal Pendidikan Kimia Unkhair (JPKU) Vol 3, No 2 (2023): Jurnal Pendidikan Kimia Unkhair (JPKU)
Publisher : Universitas Khairun

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33387/jpku.v3i2.7263

ABSTRAKÂ Penelitian ini bertujuan untuk mengetahui tingkat validasi Modul Ajar berbasis STEM (Science, Technology,Engineering, and Mathmatics) pada materi Elektrolit dan Non Elektrolit di SMA Negeri 7 Kepulauan Sula dan untuk mengetahui kelayakan terhadap modul ajar berbasis STEM (Science, Technology,Engineering, and Mathmatics) pada materi Elektrolit dan Non Elektrolit. Penelitian ini merupakan jenis penelitian pengembangan atau RD dengan menggunakan model ADDIE terdiri dari 5 tahap. Subjek dalam penelitian ini ada ahli modul, guru penanggung jawab dan siswa kelas X SMA Negeri 7 Kepulauan Sula. Objek peneltian ini adalah modul ajar berbasis STEM (Science, Technology,Engineering, and Mathmatics) pembelajaran kimia. Tehnik Pengumpulan data dari uji validitas, ujii kelayakan oleh guru dan respon siswa.Penelitian ini menghasilkan produk berupa modul ajar berbasis STEM (Science, Technology,Engineering, and Mathmatics) yang layak untuk digunakan. Hasil penelitian menunjukan tingkat validitas oleh 2 orang ahli modul masing-masing sebesar 94,5% (sangat valid), 94,5% (sangat valid) ahli materi 86,6% (sangat valid), kelayakan guru 1 96,6% (sangat praktis), kelayakan guru 2 95% (sangat layak), kelayakan guru 3 95,3% (sangat layak), kelayakan guru 4 95,3% (sangat layak) dan uji respon siswa 92% bahwa modul ajar berbasis STEM (Science, Technology,Engineering, and Mathmatics) sangat layak digunakan dalam pembelajaran.Â Kata Kunci:Â Modul Ajar Berbasis STEM Pada MateriÂ Elektrolit Dan Non ElektrolitABSTRACTThis research aims to determine the level of validation of STEM-based Teaching Modules (Science, Technology, Engineering, and Mathmatics) in Electrolyte and Non-Electrolytic materials at SMA Negeri 7 Sula Islands and to determine the feasibility of STEM-based teaching modules (Science, Technology, Engineering, and Mathmatics) in Electrolyte and Non-Electrolytic materials. This research is a type of development research or RD using the ADDIE model consisting of 5 stages. The subjects in this study are module experts, teachers in charge and students of grade X of SMA Negeri 7 Sula Islands. The object of this study is a STEM-based teaching module (Science, Technology, Engineering, and Mathmatics) learning chemistry. Techniques for data collection from validity tests, due diligence by teachers and student responses. This research produces products in the form of STEM-based teaching modules (Science, Technology, Engineering, and Mathmatics) that are suitable for use. The results showed the validity level by 2 module experts each of 94.5% (very valid), 94.5% (very valid) material experts 86.6% (very valid), teacher eligibility 1 96.6% (very practical), teacher eligibility 2 95% (very feasible), teacher eligibility 3 95.3% (very feasible), teacher eligibility 4 95.3% (very feasible) and student response test 92% that STEM-based teaching modules (Science, Technology, Engineering, and Mathmatics) are very suitable for use in learning.Keywort:Â Based Teaching Module STEM on Electrolyte and Non-Electrolyte Matherials

MALACHITE GREEN TRANSPORT USING POLYMER INCLUSION MEMBRANE METHOD WITH co-EDVB AS CARRIER Aprilia, Kharisma Citra; Safitri , Nurul Ulfa; Rakhman, Khusna Arif; Kiswandono , Agung Abadi
Walisongo Journal of Chemistry Vol. 8 No. 1 (2025): Walisongo Journal of Chemistry
Publisher : Department of Chemistry Faculty of Science and Technology UIN Walisongo

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21580/wjc.v8i1.25826

Malachite green (MG) is a synthetic dye known for its toxic and carcinogenic properties, necessitating effective removal from aquatic environments. This study investigated the use of a polymer inclusion membrane (PIM) containing co-poly(eugenol-divinylbenzene) (co-EDVB) 2% as a carrier for the selective transport of MG. The membrane was prepared by dissolving co-EDVB, polyvinyl chloride, and dibenzyl ether in tetrahydrofuran (THF). Several parameters were evaluated, including the pH of the source phase, the concentration of nitric acid in the receiving phase, membrane thickness, carrier concentration, transport time, and competitive transport in synthetic wastewater. UV-Visible spectrophotometric analysis at a wavelength of 613 nm revealed that the transport efficiency reached 90.95% under optimal conditions: source phase pH 7, 0.50 M HNO₃ in the receiving phase, membrane thickness T54, and 18 hours of transport. In the presence of competing metal ions such as Pb²⁺ and Cu²⁺, the efficiency decreased to 80.79%, confirming the important role of co-EDVB in enhancing transport selectivity and efficiency.

PENGGUNAAN EKSTRAK TEMBAKAU SEBAGAI INHIBITRO PADA BETON BERTULANG MENGGUNAKAN PASIR LAUT DAN AIR LAUT Sultan, Mufti Amir; Hi Abbas, Muhammad Yunus; Gaus, Abdul; Rakhman, Khusna Arif; Barmawi, Nurtalia
Teras Jurnal : Jurnal Teknik Sipil Vol. 10 No. 1 (2020): Volume 10 Nomor 1
Publisher : UNIVERSITAS MALIKUSSALEH

Korosi dapat didefenisikan secara umum sebagai pengrusakan bahan oleh lingkungannya. Struktur beton bertulang akan mengalami kerusakan akibat serangan korosi, apabila tidak ditangani akan membutuhkan biaya yang relative mahal untuk memperbaikinya. Korosi pada baja tulangan harus ditangani secara khusus. Oleh sebab itu diperlukan solusi untuk mengatasi masalah ini. Pencegahan korosi bergantung pada jenis korosi yang terjadi pada material terkorosi. Salah satu metode yang terus di kaji saat ini adalah pencegahan korosi dengan menggunakan inhibitor. Dalam penelitian ini, inhibitor yang digunakan adalah inhibitor ekstrak daun tembakau dengan variasi dan konsentrasi yang telah ditentukan yakni 0%,4% dan 8%. Metode yang digunakan untuk menganalisis laju korosi yang terjadi yaitu metode Weight Loss (kehilangan berat). Pengujian dilakukan dengan cara memberikan aliran listrik terhadap benda uji dengan menggunakan voltase sebesar 5V. Pengaliran dilakukan secara bertahap dengan interval tertentu, sehingga diperoleh efeisiensi inhibisi dalam satuan persen. Hasil penelitian menunjukkan pengaruh penambahan inhibitor ekstrak tembakau dengan metode weight loss pada konsentrasi 4% dan 8% mampu menurunkan rapat arus anodik dan katodik yang mengakibatkan laju korosi pada baja tulangan, Peningkatan konsentrasi inhibitor ekstrak tembakau pada masing-masing variasi campuran beton memiliki efesiensi inhibitor yang baik yakni 64,44% dengan air pencampur air tawar dan 20% untuk air laut pada setiap konsentrasi inhibitor 8% ekstrak tembakau.

Synergistic Effects of Problem-Based Learning and VAK Learning Styles on Critical Thinking and Self-Efficacy in High School Chemistry Sugrah, Nurfatimah; Mustafa, Linda Kurnia; Rakhman, Khusna Arif; Ahmar, Dewi Satria; Rahim, Fazly; Inayah, Nurul
Jurnal Pendidikan MIPA Vol 26, No 4 (2025): Jurnal Pendidikan MIPA
Publisher : FKIP Universitas Lampung

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.23960/jpmipa.v26i4.pp2343-2365

This study investigated the impact of learning styles and learning models on students’ critical thinking skills and self-efficacy in chemistry, with a focus on atomic structure and fundamental chemical laws. The research design employed was a quasi-experimental 2×3 factorial design with 108 tenth-grade high school students. The independent variables were the learning model (Problem-Based Learning/PBL and direct instruction) and learning styles (visual, auditory, kinesthetic). In contrast, the dependent variables were critical thinking skills and self-efficacy. Data were collected using the VAK learning style inventory, a validated critical thinking test, and a self-efficacy questionnaire. Data analysis employed two-way ANOVA followed by Tukey HSD post hoc tests. The results revealed that both learning models and learning styles significantly impacted students’ critical thinking skills. Students with kinesthetic learning styles performed better in critical thinking than those with visual or auditory learning styles. However, learning styles did not significantly influence self-efficacy, suggesting that students’ confidence is more strongly shaped by mastery experiences, positive feedback, and social support. The PBL model significantly enhanced both critical thinking skills and self-efficacy, highlighting the value of collaborative and contextual learning activities in developing higher-order thinking and motivation. A significant interaction was observed between learning styles and learning models, with a notable benefit for visual and kinesthetic learners in terms of self-efficacy. This study acknowledges the fundamental limitation of the VAK framework, as empirical evidence for its validity remains weak; hence, interpretations should be made cautiously. Theoretically, the findings support Bandura’s social cognitive theory, which emphasizes that self-efficacy and learning outcomes are shaped through active engagement and authentic experiences. Practically, this study suggests designing adaptive PBL approaches aligned with learners’ diverse characteristics to optimize both motivation and confidence in chemistry learning. Keywords: learning styles, problem-based learning (PBL), critical thinking skills, self-efficacy.

DFT-Based Study of Phenolic-Derived From Nutmeg (Myristica fragrans): Promising Bioreductants for Green Synthesis Silver Nanoparticles Nabila, Siti; Abdjan, Muhammad Ikhlas; Rakhman, Khusna Arif; Annisa, Dira Ayu; Mauraji, Ilham SW; Umar, Sudir
Molekul Vol 20 No 3 (2025)
Publisher : Universitas Jenderal Soedirman

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20884/1.jm.2025.20.3.16203

ABSTRACT. The manufacture of silver nanoparticles (AgNPs) can be synthesized by reducing silver ions Ag+ to Ag0 by a reductant. Nutmeg (Myristica fragrans) fruit extract has the potential as a natural reductant (bioreductant) that can donate electrons to reduce Ag+ as a ligand and capping agent. This study aims to identify the potential of the bioactive compounds in Myristica fragrans (Mf) extract for the green synthesis of AgNPs using several parameters, including total energy, HOMO-LUMO, Fukui function, molecular electrostatic potential (MEP), global reactivity, and UV/Vis theoretical spectral analysis. The method used is Density Functional Theory (DFT) with Becke-3-parameter Lee-Yang-Parr (B3LYP) hybrid functionals, using the 6-31G (d,p) basis set for hydrogen (H), carbon (C), oxygen (O) atoms, and the LanL2Dz for the silver (Ag) atom. The results of the study indicate that single bioactive compounds eugenol, chalcone, carvacrol, and terpineol, as well as eugenol-Ag, chalcone-Ag, carvacrol-Ag, and terpineol-Ag complexes, are good reducing agents in the process of reducing Ag+ ions to Ag0 as AgNPs. In addition, these phen-Ag complexes show electron excitation at UV/Vis spectrophotometric simulation in the 454-473 nm wavelength range. This study provides a theoretical understanding of Ag+ reduction by bioactive compounds in Mf extract for green synthesis of AgNPs, thereby providing a scientific basis for developing green methods for eco-friendly, sustainable AgNP synthesis. Keyword: Bioreductant, DFT, green synthesis, Myristica fragrans, silver nanoparticles. .

AN OVERVIEW OF ADVANCED 2,2-Diphenyl-1-picrylhydrazyl (DPPH) ANALYSIS TECHNIQUES Ratnawaty, Gervacia Jenny; Indrawati, Ratih; Wahdaniah, Wahdaniah; Rakhman, Khusna Arif
Walisongo Journal of Chemistry Vol. 8 No. 2 (2025): Walisongo Journal of Chemistry
Publisher : Department of Chemistry Faculty of Science and Technology UIN Walisongo

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.21580/wjc.v8i2.26028

Antioxidants play a crucial role in preventing oxidative damage, necessitating reliable analytical techniques for their evaluation. Oxidative stress, resulting from an imbalance between free radicals and antioxidants in the body, has been associated with various chronic diseases, including cancer, cardiovascular disorders, and neurodegenerative conditions. Therefore, accurately assessing antioxidant activity is essential for developing health-related products and validating their efficacy. This study reviewed and compared various analytical methods used to determine antioxidant activity, emphasizing their advantages, limitations, and applicability across different sample types. Traditional spectrophotometric assays, such as the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method, remain widely used because of their simplicity and cost-effectiveness, although they often suffer from matrix interferences. Advanced techniques, including gas chromatography–mass spectrometry (GC–MS), high-performance liquid chromatography coupled with DPPH (HPLCDPPH), electrochemical methods, microfluidic systems, and miniaturized paper-based assays, provide improved sensitivity, accuracy, and efficiency. These methods enable a more comprehensive assessment of antioxidant activity by offering deeper insights into reaction mechanisms and compound interactions. The integration of multiple analytical approaches can further enhance antioxidant characterization, supporting applications in the food, pharmaceutical, and biomedical industries. This review highlights the importance of selecting appropriate analytical techniques based on research objectives and sample characteristics, while also outlining future directions for advancing antioxidant detection methodologies.

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