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All Journal Abdimas Jurnal Bahan Alam Terbarukan Sainteknol : Jurnal Sains dan Teknologi Jurnal Kimia dan Kemasan Chemistry in Education Indonesian Journal of Chemical Science Journal of Economic Education Jurnal Penelitian Pendidikan IPA (JPPIPA) ABDIMAS SILIWANGI Journal of Innovative Science Education International Journal of Active Learning Jurnal Pengabdian Masyarakat Khatulistiwa Jurnal Kimia dan Kemasan Jurnal Abdimas Kartika Wijayakusuma International Journal of Research Innovation and Entrepreneurship Proceeding of International Conference on Science, Education, and Technology Molekul: Jurnal Ilmiah Kimia al Kimiya : Jurnal Ilmu Kimia dan Terapan Indonesian Journal of Chemical Science Jurnal Abdimas International Journal of Active Learning
Cepi Kurniawan
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Agriculture, Biological Sciences & Forestry Arts Humanities Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Computer Science & IT Earth & Planetary Sciences Economics, Econometrics & Finance Education Environmental Science Languange, Linguistic, Communication & Media Law, Crime, Criminology & Criminal Justice Library & Information Science Materials Science & Nanotechnology Physics Public Health Social Sciences Other

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Pengaruh Konsentrasi Metilenbisakrilamida dalam Sintesis Komposit Poli(Asam Akrilat)-Kaolin dan Pengujiannya sebagai Superabsorben Rakhmawati, Indri; Kurniawan, Cepi; Harjono, Harjono
Indonesian Journal of Chemical Science Vol 8 No 2 (2019)
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/ijcs.v8i2.27660

Abstract

Pada umumnya superabsorben terbuat dari polimer sintetis berbasis poliasam akrilat, tetapi penggunaan polimer jenis ini memiliki keterbatasan dalam menyerap air dan swelling karena karakteristik fisik yang kurang kuat dan tidak stabil. Mineral alam berupa kaolin ditambahkan untuk memperbaiki kelemahan ini karena memiliki gugus fungsional Si–OH sebagai penguat dalam pembentukan polimer komposit. Superabsorben komposit poli(asam akrilat)-kaolin telah dibuat dengan menggabungkan polimer dari monomer asam akrilat dengan kaolin melalui polimerisasi radikal bebas oleh inisiator amonium persulfat (APS) dan polimerisasi ikat silang oleh agen pengikat silang N,N’-metilenbisakrilamida (MBA). Pengaruh jumlah MBA dipelajari berdasarkan kapasitas absorpsi dan rasio swelling superabsorben. Hasil penelitian menunjukkan bahwa superabsorben yang dihasilkan memiliki nilai optimum pada 1% MBA terhadap Asam akrilat dengan waktu reaksi 3 jam, nilai kapasitas absorpsi air sebesar 1972,49 % (b/b) dan rasio swelling sebesar 19,7249 g/g. Semakin banyak MBA berpengaruh terhadap bertambahnya kapasitas absorpsi air dan rasio swelling dari superabsorben. Sedangkan semakin panjang waktu reaksi berpengaruh terhadap bertambahnya kapasitas absorpsi air dan rasio swelling superabsorben, tetapi mengalami penurunan kembali setelah tercapai titik optimum. Selain itu, pengujian recycle menunjukkan bahwa nilai kapasitas absorpsi air dan rasio swelling secara bertahap meningkat. Hasil SEM memperlihatkan adanya mikropori sebagai tempat permeasi air.Pengaruh Konsentrasi Metilenbisakrilamida dalam Sintesis Komposit Poli(Asam Akrilat)-Kaolin dan Pengujiannya sebagai Superabsorben.
Pengelupasan Lapisan Grafit secara Elektrokimia dalam Suasana Asam Ramadhan, Dinar Alghifari; Kurniawan, Cepi; Mahatmanti, F Widhi
Indonesian Journal of Chemical Science Vol 8 No 2 (2019)
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/ijcs.v8i2.28452

Abstract

Abstrak Grafen merupakan alotrop karbon yang paling diminati untuk diteliti dalam bidang ilmu material dikarenakan sifat khasnya. Seiring dengan aplikasi grafen, eksplorasi metoda preparasi yang sederhana terus dikembangkan. Kendala utama dalam preparasi grafen diantaranya adalah kebutuhan bahan kimia yang banyak dan tidak ramah lingkungan. Dalam penelitian ini dilakukan preparasi grafen menggunakan metode pengelupasan elektrokimia dalam dalam elektrolit asam fosfat. Sumber grafit yang digunakan adalah pinsil 6B dan konsentrasi asam fosfat 1M. reaksi pengelupasan elektrokimia dilakukan dalam tabung reaksi berbentuk U. Hasil pengelupasan berbentuk serbuk hitam halus, di bawah pengamatan SEM serbuk ini terlihat sebagai lembaran. Hasil pengujian FTIR menunjukkan adanya vibrasi pada daerah 1564 cm-1 yang merupakan vibrasi karakteristik dari gugus C=C dari grafen. Abstract Graphene is the most desirable carbon allotrope for research in the field of material science due to its characteristics. Along with graphene applications, simple exploration of preparation methods continues to be developed. The main constraints in graphical preparation include the need for many chemicals and not being environmentally friendly. In this study graphene preparation was carried out using the electrochemical exfoliation method in phosphoric acid electrolytes. The graphite source used is pencil 6B and 1M phosphoric acid concentration. the electrochemical exfoliation reaction is carried out in a U-shaped test tube. The exfoliation is in the form of fine black powder, under the observation of SEM the powder is seen as a sheet. The FTIR test results showed a vibration in the area of 1564 cm-1 which is a characteristic vibration of the C = C group of graphene.
Cerium, Neodimium, and Lanthanum Leaching from Rare Earth Oxides (REO) using Hydrochloric Acid Aulia, Muhammad Azmi; Kurniawan, Cepi; Setyadji, Moch.
Indonesian Journal of Chemical Science Vol 10 No 2 (2021)
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/ijcs.v10i2.45818

Abstract

Rare earth metal hydroxide (REOH) is a mixture of the elements lanthanide, yttrium, and scandium produced from the processing of monazite sand. This mixture has benefits in the modern technology industry, especially elements of Ce, La, and Nd. Separation of Ce, La, and Nd from the mixture has been carried out, but it has several drawbacks with the large use of chemicals that have an impact on the environment from the results of their processing waste and the length of time it takes, so the best solution is needed to overcome it. The perfect solution in the process of separating Ce, La, and Nd from REOH is leaching. Leaching is the extraction of acids with bases to form salt and water. This research begins with the REOH calcination process at a temperature of 1000⁰ C for 2 hours to evaporate volatiles and decompose the compounds. The results of calcination were leached using hydrochloric acid with a concentration variation of 0.3-1.2 M, temperature 30-75 ° C, a ratio of REO and solvent 1:5, and time variation of 5-20 minutes to optimize leaching efficiency. The results of leaching in residues were analyzed by XRF. The optimum leaching of the variation of the concentration of hydrochloric acid 1,2 M for 20 minutes resulted in the leaching efficiency of La and Nd respectively 33,297% dan 26,503%, and the leaching efficiency of Ce was 10,153% of the concentration of hydrochloric acid 0,9 M for 20 minutes. At a temperature variation of 75⁰ C and a time of 10 minutes, the leaching efficiency La and Ce were 55,87% dan 0,04%, respectively. The efficiency of Nd at 45⁰C for 20 minutes was 26,93%.
Steel Corrosion Protection with Water-Soluble Chitosan Inhibitor in 0,1 M HCl Solution Media Fitria, Reffy Ika; Mahatmanti, F. Widhi; Kurniawan, Cepi; Kusumastuti, Ella
Indonesian Journal of Chemical Science Vol 10 No 1 (2021)
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/ijcs.v10i1.46015

Abstract

Corrosion in steel can reduce the steel quality, so it is necessary to have a corrosion inhibitor. Water-soluble chitosan can be an alternative as corrosion inhibitors. This study aims to determine the efficiency of water-soluble chitosan inhibitor (WSC) added to the corrosive HCl solution in the steel protection process, and to determine the maximum concentration of WSC as a steel corrosion protector. Water-soluble chitosan (WSC) has been prepared from chitosan by reacting with H2O2. The products obtained were used as corrosion protection inhibitors in steel in a corrosive solution of 0,1 M HCl. Chitosan and WSC were characterized by their physical properties and functional groups using FTIR and physical tests for yield, viscosity, molecular weight (BM),% DD, solubility, and water content. . The effectiveness of WSC in corrosion protection of steel in corrosive 0,1 M HCl solution was studied by weight loss and potentiodynamic polarization methods. The results obtained by chitosan were a viscosity of 1,4969 cP, BM 8,38 x 104,% DD 77,17%, 10,25% moisture content and 33,48% solubility. Water-soluble chitosan obtained yield 86.325%, viscosity 0,296 cP, BM 6,9 x 103,% DD 79,95%, water content 27,07% and 72,77% solubility. Inhibitor efficiency was found in WSC 2000 ppm and 0,1 M HCl, which was 68,15% EI (weight loss), while the potentiodynamic polarization method obtained an EI of 87,5%.
Voltammetric Analysis of Pb2+ Ion on Gold Nanoparticles-Modified ZnO Electrode Fauziah, Rahmi; Kurniawan, Cepi
Sainteknol : Jurnal Sains dan Teknologi Vol 19, No 2 (2021): December 2021
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/sainteknol.v19i2.33190

Abstract

Waste such as heavy metal is a very dangerous toxic material, the heavy metal that is often used is lead (Pb). In this study, heavy metal detection was carried out with the material used, namely ZnO because it has high sensitivity in heavy metal detection. ZnO will be modified with gold nanoparticles (AuNP). AuNP has been used for surface decoration of oxides to obtain high sensor performance which is 6.5 times faster than without the addition of Au. Research has been carried out on the Voltammetric Analysis of Pb2+ Ion on Gold Nanoparticles-Modified ZnO Electrode. This study aims to determine the nature and characteristics of the ZnO/AuNP compound deposited on the SPCE electrode and to determine the selectivity and sensitivity of the ZnO/AuNP electrodeposition on the SPCE electrode to identify heavy metals. FTIR characterization showed that there was a Zn-O bond in the synthesized compound. SEM characterization showed hexagonal morphology. The PSA results showed the size of the AuNP was 115.7 nm. The test results of the ZnO/AuNP5%/SPCE electrode sensor have a LoD value of 2.88 ppm and a LoQ of 9.60 ppm, a sensitivity of 0.077 µA µg-1 L., and R2 = 0.96862.
Electroanalysis of Formaldehyde Using Electrodeposited Nickel on Glassy Carbon Electrode Syaifariz, Akbar; Kurniawan, Cepi
Sainteknol : Jurnal Sains dan Teknologi Vol 19, No 1 (2021): June 2021
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/sainteknol.v19i1.33189

Abstract

Formaldehyde in many cases was found in foods as a preservative or as a result of polymer degradation from food containers. As matter of fact, formaldehyde is carcinogenic, irritant, and toxic to the body, so an efficient analytical method is needed to detect formaldehyde. The analytical method using electroanalysis is used because it can be fast, accurate, inexpensive, and easy to operate. Electroanalysis of formaldehyde using nickel electrodes deposited on Glassy Carbon (GC) has been carried out using cyclic voltammetry technique. The variation of nickel deposition time for 300 seconds (GC-Ni5m) and 600 seconds (GC-Ni10m) was carried out to determine its effect on formaldehyde detection ability through analysis of electroanalytical activity and the resulting detection and quantification limits. Through the cyclic voltammetry technique, two types of linear ranges were used; low concentrations (0.1–50 ppm) and high concentrations (50–500 ppm). The detection limits for GC-Ni5m were 33.1 ppm (low concentration) and 49.7 ppm (high concentration), while GC-Ni10m were 35.8 ppm (low concentration) and 69.9 ppm (high concentration). The electroanalytical method was compared with the spectrophotometric method using Schiff's reagent with a detection limit were 17.8 ppm (low concentration) and 106.6 ppm (high concentration).
Color and Chemical Oxygen Demand Removal of Strobilanthes cusia Fermentation and Natural Indigo-based Batik Dyeing Wastewater Kurniawan, Cepi; Mahatmanti, F. Widhi; Mahfudz, Johar; Qonita, Ulya; Nugraha, Rizki; Bahron, Hadariah
International Journal of Research Innovation and Entrepreneurship Vol 2 No 1 (2021): June 2021
Publisher : Universitas Negeri Semarang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.15294/ijrie.v2i1.48688

Abstract

Strobilanthes cusia is the plant which has been cultivated at the District of Temanggung, Indonesia and used as a natural source for indigo dye. The use of natural dyes for Batik Industries are expected to prohibit environmental damage. However, the wastewater generated from the indigo extraction and Batik dyeing process is still showing high COD value (768-3.893 ppm). In the present study, color and COD removal from Strobilanthescusia processing (settling pond) and Indigo-based Batik dyeing (equalization tank) wastewater have been studied. The treatment involving the use of FeSO4, Alum, and Cyclea Barbata Miers. powder (CBM) as coagulation-flocculation agents. Alum was efficiently reduced color up to 97% and 93% for settling pond and equalization tank effluent, respectively. The highest COD removal efficiencies of 87 % and 63% were observed for settling pond and equalization tank effluent, respectively.
EKSTRAKSI INDIGO DARI DAUN STROBILANTHES CUSIA DAN KAJIAN PEMBENTUKAN KOMPLEKS DENGAN ION Ni2+ Cepi Kurniawan
Jurnal Kimia dan Kemasan Vol. 42 No. 2 Oktober 2020
Publisher : Balai Besar Kimia dan Kemasan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24817/jkk.v42i2.5977

Abstract

Kajian ekstraksi zat warna alam indigo dari tanaman Strobilanthes cusia telah dilakukan. Ekstraksi dilakukan dengan metode fermentasi daun dan batang Strobilanthes cusia selama 48 jam diikuti oleh oksidasi dalam suasana basa. Indigo tidak dapat diperoleh secara langsung dari tanaman, melainkan sebagai senyawa glukosa indoksil. Ekstrak Strobilanthes cusia mengandung dua zat warna didalamnya yaitu indigo (biru) dan indirubin (merah). Pemisahan dilakukan dengan metode kromatografi lapis tipis dan kolom. Variasi pelarut terbaik yaitu campuran dari kloroform:n-heksana:metanol (8:5:0,5) karena menghasilkan pemisahan baik. Pemisahan ini menghasilkan nilai Rf sebesar 0,2 untuk indigo dan indirubin 0,428. 1 kg daun strobilanthes cusia menghasilkan 195 mg pewarna indigo dan 89 mg indirubin. Senyawa indigo memiliki serapan maksimum pada 600 nm. Puncak serapan pada 800 nm teramati ketika indigo dicampurkan dengan Ni2+. Keberadaan puncak ini mengindikasikan pembentukan senyawa kompleks antara indigo dengan ion Ni2+. Dari penelitian ini, diperoleh juga bahwa senyawa Ni-Indigo berpotensi sebagai pewarna pada sel surya.
EKSTRAKSI INDIGO DARI DAUN STROBILANTHES CUSIA DAN KAJIAN PEMBENTUKAN KOMPLEKS DENGAN ION Ni2+ Cepi Kurniawan
Jurnal Kimia dan Kemasan Vol. 42 No. 2 Oktober 2020
Publisher : Balai Besar Kimia dan Kemasan

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24817/jkk.v42i2.5977

Abstract

Kajian ekstraksi zat warna alam indigo dari tanaman Strobilanthes cusia telah dilakukan. Ekstraksi dilakukan dengan metode fermentasi daun dan batang Strobilanthes cusia selama 48 jam diikuti oleh oksidasi dalam suasana basa. Indigo tidak dapat diperoleh secara langsung dari tanaman, melainkan sebagai senyawa glukosa indoksil. Ekstrak Strobilanthes cusia mengandung dua zat warna didalamnya yaitu indigo (biru) dan indirubin (merah). Pemisahan dilakukan dengan metode kromatografi lapis tipis dan kolom. Variasi pelarut terbaik yaitu campuran dari kloroform:n-heksana:metanol (8:5:0,5) karena menghasilkan pemisahan baik. Pemisahan ini menghasilkan nilai Rf sebesar 0,2 untuk indigo dan indirubin 0,428. 1 kg daun strobilanthes cusia menghasilkan 195 mg pewarna indigo dan 89 mg indirubin. Senyawa indigo memiliki serapan maksimum pada 600 nm. Puncak serapan pada 800 nm teramati ketika indigo dicampurkan dengan Ni2+. Keberadaan puncak ini mengindikasikan pembentukan senyawa kompleks antara indigo dengan ion Ni2+. Dari penelitian ini, diperoleh juga bahwa senyawa Ni-Indigo berpotensi sebagai pewarna pada sel surya.
PELATIHAN GURU-GURU KIMIA DALAM PEMBUATAN VIDEO AJAR UNTUK PEMBELAJARAN DARING Cepi Kurniawan; Murbangun Nuswowati; Sri Kadarwati; Harjito Harjito; Arma Yoga
Jurnal Pengabdian Masyarakat Khatulistiwa Vol 4, No 1 (2021): APRIL
Publisher : STKIP Persada Khatulistiwa Sintang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31932/jpmk.v4i1.921

Abstract

ABSTRAKMasa pandemic COVID-19 di Indonesia yang dimulai pada bulan Maret 2020 memaksa semua proses belajar mengajar dialihkan pada sistem pembelajaran daring (online). Terlepas dari belum terbangunnya kultur guru dalam mengelola pembelajaran daring, pemberlakuan proses belajar mengajar tanpa tatap muka ini telah memaksa guru lebih kreatif dalam membuat media pembelajaran. Di samping aspek praktis, Guru-guru harus siap dan menyiapkan diri untuk mampu berperan sebagaimana tuntutan kurikulum. Kualitas pembelajaran daring mempunyai akar permasalahan yang tidak sederhana, mulai dari minimnya sumber belajar daring, kendali waktu belajar, akses internet, dan lainnya. Mengacu uraian pada analisis situasi dapat diidentifikasi permasalahan utama mitra yaitu guru sains utamanya pada kelompok Guru Kimia PPG Daljab 2020. Terdapat peningkatan keterampilan guru dalam menggambarkan struktur molekul kimia dan juga kemampuan menyiapkan video ajar menggunakan PowerPoint. Namun, devais yang dimiliki kurang support untuk rendering video jika PowerPoint memiliki banyak gambar dan atau video.Kata Kunci: Pembelajaran daring; covid-19; Guru Kimia; video ajar; PowerPoint ABSTRACTThe period of the COVID-19 pandemic in Indonesia which began in March 2020 forced all teaching and learning processes to be shifted to an online learning system. Apart from the absence of a teacher culture in managing online learning, the implementation of this face-to-face teaching and learning process has forced teachers to be more creative in making learning media. In addition to the practical aspects, teachers must be ready and prepared to be able to play a role as the curriculum demands. The quality of online learning has roots that are not simple, starting from the lack of online learning resources, control of study time, internet access, and so on. Referring to the description of the situation analysis, the main problems of partners can be identified, namely science teachers, especially in the in-service Chemistry Teachers group. There is an increase in the skills of teachers in describing chemical molecular structures and also the ability to prepare teaching videos using PowerPoint. However, the device does not have support for rendering video if PowerPoint has lots of images and / or videos.Keywords: online-learning; COVID-19; Chemistry Teachers; Teaching Video; PowerPoint.
Co-Authors - Jumaeri Agung Tri Prasetya Alvin Nur Zahro Annisa Lestari Aris Wijayanti Arma Yoga Atika Wijaya Aulia, Muhammad Azmi Aulia, Syiva Zakia Azzahra, Elvara Siti Bahron, Hadariah Budi Astuti Didik Prasetyoko Dimas Gilang Ramadhani, Dimas Gilang Doni Setiawan Edy Cahyono Eko Budi Susatyo Ella Kusumastuti, Ella Endang Susilaningsih F Widhi Mahatmanti Fitria, Reffy Ika Haq, Ismi Arinal Harjito - Harjito Harjito Harjono Harjono Harjono Herlina Dewi, Siti Hilda, Shinta Ida Norma Sinta, Ida Norma Irawati Irawati Ladjidji, Delfris Ariya Pratama Mahfudz, Johar Massora, Kris Maylia Rosanti, Yuan Moch. Setyadji Mohammad Alauhdin, Mohammad Murbangun Nuswowati Nisa, Hoirun Nugraha, Rizki Nuni Widiarti Nurfaijah, Siti Nuril Huda Oktaviyanti, Dita Try Prahasti Cynthia Hardiyanti, Prahasti Cynthia Pramestia, Rena Aliya Prasetyo, Ridho Qonita, Ulya Rahmi Fauziah, Rahmi Rakhmawati, Indri Ramadhan, Dinar Alghifari Rohmah, Rojja Maysa Rosanti, Yuan Maylia Rubi’ah, Rubi’ah Sabatinie, Indrie Sabrina Dwie Karunia, Sabrina Dwie Sri Haryani Sri Kadarwati Sri Nurhayati Sri Susilogati Sumarti SRI WARDANI Sucihatiningsih Dian Wisika Prajanti Sudarmin Sudarmin Sukarjo Sukarjo, Sukarjo Sulistyani, Martin Sulistyaningrum, Devitri Sungkowo Sungkowo, Sungkowo Suprapto, Surapto Sutikno Madnasri Syaifariz, Akbar Teguh Budiyanto, Teguh Tri Prasetya, Agung Wara Dyah Pita Rengga Warlan Sugiyo Widastra, Holifiled Woro Sumarni Yulianto, Agung Ade Yusuf Nugi Nugraha Zahrotil Umami, Min