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All Journal Sodality: Jurnal Sosiologi Pedesaan International Journal of Renewable Energy Development Jurnal Riset Kimia Alchemy Jurnal Penelitian Kimia Indonesian EFL Journal Edulingua: Jurnal Linguistiks Terapan dan Pendidikan Bahasa Inggris JPPS (Jurnal Penelitian Pendidikan Sains) International Journal of Science and Society (IJSOC) EPIGRAM (e-journal) POLICY, LAW, NOTARY AND REGULATORY ISSUES (POLRI) Jurnal Natural Jurnal MIPA dan Pembelajarannya Molekul: Jurnal Ilmiah Kimia Dedikasi: Journal of Community Engagement and Empowerment Prosiding Temu Ilmiah Nasional Guru International Journal of Renewable Energy Development Muara: Jurnal Manajemen Pelayaran Nasional Jurnal Rekayasa Proses
Fitria Rahmawati
Research Group of Solid State Chemistry & Catalysis, Chemistry Department, Sebelas Maret University, Jl. Ir. Sutami 36 A Kentingan, Surakarta
Agriculture, Biological Sciences & Forestry Arts Humanities Astronomy Biochemistry, Genetics & Molecular Biology Chemical Engineering, Chemistry & Bioengineering Chemistry Control & Systems Engineering Decision Sciences, Operations Research & Management Earth & Planetary Sciences Economics, Econometrics & Finance Education Electrical & Electronics Engineering Energy Engineering Environmental Science Immunology & microbiology Languange, Linguistic, Communication & Media Law, Crime, Criminology & Criminal Justice Materials Science & Nanotechnology Mathematics Neuroscience Physics Social Sciences Other

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CATALYST TABLET OF Cu-TiO2/GRAPHITE FOR PHOTO-AND ELECTRO-ASSISTED DEGRADATION OF REMAZOL YELLOW FG Rahmawati, Fitria; Apriyani, Rochmi I.; Rahardjo, Sentot B.
Alchemy Jurnal Penelitian Kimia Vol 8, No 2 (2012)
Publisher : Alchemy Jurnal Penelitian Kimia

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Abstract

Titanium dioxide (TiO2) film was supported on graphite (G) by means of chemical bath deposition (CBD) from TiCl4 precursor. Meanwhile surfactant cetyl trimethyl ammonium bromide (CTAB) was added as linking and assembling agent between titanium network and graphite substrate. Cu was deposited electrochemically from 0.4 M of CuSO4 solution at 0.03 A of electric current. The tablets of TiO2/G and Cu-TiO2/G were used as catalyst for photocatalytic degradation (PC), electrocatalytic degradation (ED) and photoelectrocatalytic (PEC) degradation of Remazol Yellow FG. In degradation system which used TiO2/G tablet, the highest rate constant, k, was achieved by PEC method, k was 2.810-3 min-1, as well as in the system which used Cu-TiO2/G tablet. However, this research founded that direct oxidation by external electric field contribute more to degradation process than photocatalytic mechanism, proved by high rate constant of ED, k was 2.610-3 min-1. Meanwhile, rate constant of photocatalytic degradation was 510-4 min-1. This research also founded that TiO2 film highly contribute in degradation process due to the fact that rate constant of electrodegradation by using blank graphite is low, k was 510-4 min-1. Meanwhile, deposition of Cu onto TiO2 did not enhance degradation rate of remazol yellow by PEC method, however it enhanced the rate constant of ED to 2.710-3 min-1. The FTIR analysis to the completedly degraded remazol yellow FG solution shows disappearance of N=N stretching at 1559 cm-1and as CH2 at 2919 cm-1. This indicates that molecular structure of remazol yellow has been degraded succesfully then convert this dye solution into clear solution.Keywords : Cu-TiO2/graphite, electrocatalytic degradation, photoelectrocatalytic degradation, remazol yellow FG, TiO2/Graphite.
ADSORPSI ZAT WARNA TEKSTIL REMAZOL YELLOW FG PADA LIMBAH BATIK OLEH ECENG GONDOK DENGAN AKTIVATOR NaOH Rahmawati, Fitria; ., Pranoto; Aryunani, N Ita
Alchemy Jurnal Penelitian Kimia Vol 2, No 2 (2003)
Publisher : Alchemy Jurnal Penelitian Kimia

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Abstract

Telah dilakukan penelitian penggunaan eceng gondok sebagai sumber selulosa untuk menyerap limbah zat warna tekstil Remazol Yellow FG. Dalam penelitian ini, eceng gondok diaktivasi dahulu dengan larutan NaOH 2% , kemudian dicuci sampai netral. Waktu perendaman eceng gondok dalam larutan NaOH tersebut divariasi untuk mendapatkan kondisi eceng gondok aktif yang mempunyai daya serap maksimum. Selanjutnya pada proses adsorpsi dilakukan variasi pH basa dan waktu kontak. Setelah mendapatkan kondisi optimum kemudian menentukan isoterm adsorpsi dan diaplikasikan pada limbah zat warna tekstil Remazol Yellow FG. Kondisi penyerapan optimum zat warna tekstil Remazol Yellow FG oleh eceng gondok aktif dalah pada wktu perendaman 24 jam, pH 11, dan waktu kontak 1 jam. Daya serap eceng gondok aktif terhadap zat warna tekstil sbesar 3,64mg/g sedangkan pada limbah zat warna tekstil sebesar 4,44mg/g. Analisis isoterm adsorpsi eceng gondok aktif terhadap zat warna tekstil mengikuti persamaan Langmuir (adsorpsi kimia). Karakteristik eceng gondok aktif mempunyai luas permukaan yang lebih besar dibandingkan eceng gondok alam. Analisis gugus fungsi menunjukkan adanya gugus O-H, vas CH2, C=O, C-H, dan C-O pada eceng gondok aktif.
REVERSE MICROEMULSION OF IGEPAL CO-720 SYSTEM AS MICROREACTOR FOR CdS Rahmawati, Fitria; Fitriani, Indah Rizki; Masykur, Abu
Alchemy Jurnal Penelitian Kimia Vol 10, No 2 (2014)
Publisher : Alchemy Jurnal Penelitian Kimia

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A Research on CdS synthesis in reverse microemulsion of Igepal CO-720 system has been conducted at various weight ratio of water to surfactant. Igepal CO-720 naturally forms oil in water (o/w) emulsion type due to its high HLB (Hydrophilic-Lipophilic Balance) value. Therefore, in this research the Igepal CO-720 system was inversed into water in oil (w/o) system before it was used as microreactor for CdS synthesis. As comparison, a system of AOT (Aerosol OT; sodium bis(2-ethylhexyl) sulfosuccinate) which is naturally w/o system was also used as microreactor for CdS synthesis. The prepared CdS was analyzed by X-ray diffraction for crystal identification, scanning electron microscope for morphological analysis, UV-Vis for absorption edge determination and photoelectrochemical testing for photoactivity. The results show that the Igepal CO-720 system can be inverted into w/o system and can be used as microreactor for CdS synthesis. The prepared CdS is in nanosize with the average diameter of 2.517 ± 0.014 nm and the average gap energy of 3.805 ± 0.178 eV. The prepared CdS in Igepal CO-720 system has less regular form in comparison with morphology of the prepared CdS in AOT system. As the w values decreases the particle diameter decreases, the gap energy increases and the %IPCE increases. It indicates that high surfactant concentration allows small size micelles formation and produced smaller CdS particle that has high surface area and therefore provide higher photocatalytic activity which was indicated by high value of its %IPCE.
SINTESIS SEMIKONDUKTOR ZnS DALAM MIKROEMULSI HASIL TRANSFORMASI FASA SISTEM n-HEKSANA/ SDS/ ETANOL/ AIR Rahmawati, Fitria; Masykur, Abu; Siagian, Bintang Junita
Alchemy Jurnal Penelitian Kimia Vol 3, No 2 (2004)
Publisher : Alchemy Jurnal Penelitian Kimia

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Telah dilakukan sintesis semikonduktor ZnS menggunakan mikroemulsi sistem n-heksana/ SDS/ Etanol/ Air yang merupakan emulsi O/W (oil in water ) yang ditransformasikan menjadi W/O (water in oil) dengan metode penambahan fasa organik secara bertahap, di mana titk inversi fasa diketahui dari pengukuran konduktivitas sistem sebagai fungsi penambahan fasa organik (n-heksana).Pengukuran konduktivitas sistem menunjukkan bahwa inversi emulsi terjadi pada penambahan n-heksana 30 ml untuk semua variasi massa SDS ynag digunakan. Karakteristik ZnS hasil sintesis menggunakan spektrofotometer XRD menunjukkan kadar ZnS dalam kristal hasil sintesis sebesar 39,582%. Karakterisasi serapan UV-Vis menunjukkan bahwa penurunan nilai  ?  ([H2O]/[SDS]) menyebabkan penurunan diameter partikel ZnS hasil sintesis, pergeseran serapan ke  ?  yang lebih kecil dan nilai Eg yang semakin besar.
CATALYST TABLET OF Cu-TiO2/GRAPHITE FOR PHOTO-AND ELECTRO-ASSISTED DEGRADATION OF REMAZOL YELLOW FG Rahmawati, Fitria; Apriyani, Rochmi I.; Rahardjo, Sentot B.
Alchemy Jurnal Penelitian Kimia Vol 8, No 1 (2012)
Publisher : Alchemy Jurnal Penelitian Kimia

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Abstract

Titanium dioxide (TiO2) film was supported on graphite (G) by means of chemical bath deposition (CBD) from TiCl4precursor. Meanwhile surfactant cetyl trimethyl ammonium bromide (CTAB) was added as linking and assembling agent between titanium network and graphite substrate. Cu was deposited electrochemically from 0.4 M of CuSO4solution at 0.03 A of electric current. The tablets of TiO2/G and Cu-TiO2/G were used as catalyst for photocatalytic degradation (PC), electrocatalytic degradation (ED) and photoelectrocatalytic (PEC) degradation of Remazol Yellow FG. In degradation system which used TiO2/G tablet, the highest rate constant, k, was achieved by PEC method, kwas 2.8´10-3 min-1, as well as in the system which used Cu-TiO2/G tablet. However, this research founded that direct oxidation by external electric field contribute more to degradation process than photocatalytic mechanism, proved by high rate constant of ED, k was 2.6´10-3 min-1. Meanwhile,  rate constant of photocatalytic degradation was 5´10-4min-1. This research also founded that TiO2 film highly contribute in degradation process due to the fact that rate constant of electrodegradation by using blank graphite is low, k was 5´10-4 min-1. Meanwhile, deposition of Cu onto TiO2 did not enhance degradation rate of remazol yellow by PEC method, however it enhanced the rate constant of ED to 2.7´10-3 min-1. The FTIR analysis to the completedly degraded remazol yellow FG solution shows disappearance of N=N stretching at 1559 cm-1and uas CH2 at 2919 cm-1. This indicates that molecular structure of remazol yellow has been degraded succesfully then convert this dye solution into clear solution.
FAKTOR TEGANGAN OPERASI DAN JARAK ANTARA ELEKTRODA PADA PEMECAHAN EMULSI MINYAK DALAM AIR SECARA ELEKTROKOAGULASI Rahmawati, Fitria
Alchemy Jurnal Penelitian Kimia Vol 1, No 2 (2002)
Publisher : Alchemy Jurnal Penelitian Kimia

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Pemecahan emulsi minyak dalam air diteliti pada temperatur kamar (28oC) dengan menggunakan anoda besi dan katoda karbon . Pada penelitian ini dipelajari pengaruh pemberian tegangan operasi dan jarak antar elektroda terhadap hasil pemecahan emulsi minyak dalam air yang dianalisa secara gravimetri partisi dengan sampel fasa ruah emulsi dalam sel elektrokoagulasi. Hasil analisis sampel fasa ruah membuktikan adanya pengaruh sebanding dari tegangan operasi terhadap hasil pemecahan emulsi, dan penurunan pemecahan emulsi dengan meningkatnya jarak antar elektroda. Analisis statistik terhadap data penelitian membuktikan bahwa interaksi kedua faktor percobaan sangat nyata dan kondisi optimum didapatkan pada jarak antar elektroda 1 cm – 2 cm dengan tegangan operasi 2,5 volt.
REACTION KINETICS OF Cu ELECTRO-DEPOSITION ON THE SURFACE OF TiO2/GRAPHITE Rahmawati, Fitria; Mawasthi, Wanodya Anggit; -, Patiha
Jurnal Riset Kimia Vol 8, No 2 (2015): March
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jrk.v8i2.228

Abstract

Research on the kinetics of electrode reaction during copper electro-deposition on the surface of TiO2/graphite has been conducted. The aims of this research are to determine the ratio of anodic reaction rate to cathodic reaction rate , the ratio of anodic rate constant to cathodic rate constant , the equilibrium constant when the reaction reach equilibrium condition and to study the polarization in the electro-deposition reaction. Copper was deposited electrochemically from CuSO4 solution at various concentration i.e. 0.1 M; 0.2 M; 0.3 M; 0.4 M; 0.5 M. In every 5 minutes during electro-deposition process, the pH changes in anode cell was recorded and the change of Cu2+ concentration was also analyzed by spectrophotometric method. The result shows that the reaction order of Cu2+ reduction is first order and the oxidation of H2O in anodic cell is zero order. The ratio of anodic rate constant to cathodic rate constant, is 4.589´10-3 ± 0.071´10‑3. It indicates that the reaction rate  in cathode is larger than the reaction rate in anode and it allowed polarization.  The electrochemical cell reached equilibrium after 25 minutes with the equilibrium constant is 8.188´10-10 ± 1.628´10-10.
PENGEMBANGAN PERANGKAT PEMBELAJARAN FISIKA MODEL INKUIRI TERBIMBING BERBANTUAN VIDEOSCRIBE PADA MATERI KALOR UNTUK MENINGKATKAN HASIL BELAJAR SISWA SMAN 1 KEDUNGWARU Rahmawati, Fitria; W.W, Soegimin; Kardi, Soeparman
JPPS (Jurnal Penelitian Pendidikan Sains) Vol 5, No 2 (2016)
Publisher : Universitas Negeri Surabaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26740/jpps.v5n2.p1039-1047

Abstract

The aim of this research is to develop physics learning material based on guided inquiry model completed video scribe at heat material to improve senior high school achievement. Development of Physics Learning Material is used Dick and Carey model, this research using one-group pretest-posttest design. Data were analyzed using descriptive analysis qualitatively and quantitatively. Validation results showed that learning material is feasible to be implemented, including: (a) lesson plan; (b) student worksheet; (c) student books; (d) evaluation instrument. The results of this research were analyzed and obtained: lesson plan was properly implemented, good student responses, all students interested in learning. Learning evaluation of knowledge, N-gain include knowledge aspect and critical thinking skills, showed high improvement. Concluded that, physics learning materials developed is feasible to implemented and it can improve the student achievement Penelitian ini bertujuan mengembangkan perangkat pembelajaran fisika berbasis model inkuiri terbimbing berbantuan videoscribe yang layak untuk meningkatkan hasil belajar siswa SMA pada materi kalor. Pengembangan perangkat pembelajaran menggunakan model Dick and Carey, perangkat pembelajaran diujicobakan pada sekelompok subjek dengan rancangan one group pretest-posttest design. Data yang diperoleh dianalisis secara deskriptif kuantitatif dan kualitatif. Hasil validasi perangkat pembelajaran menunjukkan perangkat pembelajaran layak untuk diimplementasikan, meliputi: (a) RPP; (b) LKS; (c) Buku Ajar; (d) Media videoscribe; dan (e) Tes Hasil Belajar. RPP terlaksana dengan baik, dan siswa memberikan respon positif terhadap pembelajaran. N-Gain pada aspek pengetahuan dan keterampilan berpikir kritis menunjukkan peningkatan dengan kategori tinggi. Kesimpulan dari penelitian ini yakni perangkat pembelajaran yang dikembangkan layak diimplementasikan dan dapat meningkatkan hasil belajar siswa.
PENGEMBANGAN PERANGKAT PEMBELAJARAN FISIKA MODEL INKUIRI TERBIMBING BERBANTUAN VIDEOSCRIBE PADA MATERI KALOR UNTUK MENINGKATKAN HASIL BELAJAR SISWA SMAN 1 KEDUNGWARU Rahmawati, Fitria; W.W, Soegimin; Kardi, Soeparman
JPPS (Jurnal Penelitian Pendidikan Sains) Vol 5, No 2 (2016)
Publisher : Universitas Negeri Surabaya

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26740/jpps.v5n2.p1039-1047

Abstract

The aim of this research is to develop physics learning material based on guided inquiry model completed video scribe at heat material to improve senior high school achievement. Development of Physics Learning Material is used Dick and Carey model, this research using one-group pretest-posttest design. Data were analyzed using descriptive analysis qualitatively and quantitatively. Validation results showed that learning material is feasible to be implemented, including: (a) lesson plan; (b) student worksheet; (c) student books; (d) evaluation instrument. The results of this research were analyzed and obtained: lesson plan was properly implemented, good student responses, all students interested in learning. Learning evaluation of knowledge, N-gain include knowledge aspect and critical thinking skills, showed high improvement. Concluded that, physics learning materials developed is feasible to implemented and it can improve the student achievement Penelitian ini bertujuan mengembangkan perangkat pembelajaran fisika berbasis model inkuiri terbimbing berbantuan videoscribe yang layak untuk meningkatkan hasil belajar siswa SMA pada materi kalor. Pengembangan perangkat pembelajaran menggunakan model Dick and Carey, perangkat pembelajaran diujicobakan pada sekelompok subjek dengan rancangan one group pretest-posttest design. Data yang diperoleh dianalisis secara deskriptif kuantitatif dan kualitatif. Hasil validasi perangkat pembelajaran menunjukkan perangkat pembelajaran layak untuk diimplementasikan, meliputi: (a) RPP; (b) LKS; (c) Buku Ajar; (d) Media videoscribe; dan (e) Tes Hasil Belajar. RPP terlaksana dengan baik, dan siswa memberikan respon positif terhadap pembelajaran. N-Gain pada aspek pengetahuan dan keterampilan berpikir kritis menunjukkan peningkatan dengan kategori tinggi. Kesimpulan dari penelitian ini yakni perangkat pembelajaran yang dikembangkan layak diimplementasikan dan dapat meningkatkan hasil belajar siswa.
Peramalan jumlah wisatawan mancanegara ke indonesia dengan menggunakan metode autoregressive integrated moving average with exogenous variable (ARIMAX) efek variasi kalender libur akhir tahun Rahmawati, Fitria; Lestari, Trianingsih Eni
Jurnal MIPA dan Pembelajarannya Vol. 2 No. 11 (2022): Nopember
Publisher : Universitas Negeri Malang

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17977/um067v2i112022p8

Abstract

Sektor pariwisata di Indonesia merupakan salah satu andalan untuk menyerap devisa Negara. Salah satunya dari wisatawan mancanegara yang berkunjung ke Indonesia, dimana biasanya meningkat pada libur akhir tahun. Besarnya potensi ini membuat para investor asing berlomba-lomba menanamkan modal untuk membangun hotel yang dapat berakibat over supply. Untuk menangani hal tersebut diperlukan prediksi jumlah wisatawan yang akurat dengan melakukan peramalan yaitu dengan analisis deret waktu. Ketika data deret waktu memiliki variabel lebih dari satu yang disebut juga sebagai data multivariat misalkan dengan adanya penambahan variabel dummy efek variasi kalender libur akhir tahun maka salah satu metode peramalan yang bisa digunakan adalah dengan Autoregressive Integrated Moving Average with Exogenous Variable (ARIMAX) Efek Variasi Kalender. Metode ARIMAX adalah modifikasi dari model ARIMA Seasonal dengan penambahan variabel eksogen yaitu variabel dummy dan periode waktu.Dengan melihat permasalahan tersebut, penelitian ini bertujuan mengetahui model deret waktu terbaik untuk meramalkan jumlah wisatawan mancanegara dengan metode ARIMAX serta mengetahui hasil peramalan jumlah wisatawan mancanegara dengan metode ARIMAX. Berdasarkan hasil analisis terhadap jumlah wisatawan mancanegara, diperoleh bahwa model terbaik peramalan sebagai berikut Y_t=475158,2+98619,9D_1t+3650,5t+a_t 〖(1- 0,22055B)〗^(-1) 〖(1-0,48107B^12)〗^(-1) Dari model diatas diketahui bahwa peramalan untuk data ke-t dipengaruhi oleh efek variasi kalender libur akhir tahun dan periode waktu pada saat ke-t. Dan hasil peramalan jumlah wisatawan yang datang ke Indonesia dengan metode ARIMAX pada bulan Januari 2016 dan bulan februari 2016 sebesar 814052,96 dan 858423,27 orang.
Co-Authors -, Patiha Abu Masykur Alaih, Imam Shofid Albertus Sentot Sudarwanto, Albertus Sentot Atmoko, Setyo Bintang Junita Siagian, Bintang Junita Byba Melda Suhita Chanif Mahdi Chintya Dewi, Chintya Eddy Heraldy Edi Pramono Fadlulloh, Zaki Handaka, Muhammad F. A. Heliani, Kinkind Raras I F Nurcahyo, I F Indah Rizki Fitriani, Indah Rizki Ivandini Tribidasari Anggraningrum Kardi, Soeparman Khoirina Dwi Nugrahaningtyas Lego Karjoko Mahsus, Mahsus Maisaroh, Ummi Mawasthi, Wanodya Anggit Mohamad Syafri Muzayanha, Soraya U. N Ita Aryunani, N Ita Nilasary, Hanida Noffaisah B. Pasandalan, Sittie Nugraheni, Putranty Widha Nur Aini Nurcahyo, I. F. Nurcahyo, I.F. Nursukatmo, Hartoto Oktaviano, Haryo S. Paramartha, I Gusti Ayu Filia Pranoto . Puspitasari, Noviana Putri, Denis Octareta Amelia Qurrotul'aini, Nisriina 'Abidah Raihan, Edo Ratna Pertiwi, Dewanti Ridwan, Qanita Rizki Nur Analita Rochmi I. Apriyani, Rochmi I. Rosalin, Azka W Safinatunnajah, Salwa Saputri, Dini Deviana Sentot B. Rahardjo, Sentot B. Setiani, Ajeng Wahyu Shobikah, Nanik Sofia, Iva Trianingsih Eni Lestari Trise Nurul Ain Utari, Marisa Putri W.W, Soegimin Widiasih Widyowati, Agustin Wijayanta, Agung Tri Yuni, Prima Novia Yuniawan Hidayat Zalfa, Syafira Nur