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Didin Sahidin Winatapura
Synthesis, characterization, and photocatalytic activity of fe3O4@zno nanocomposite
"A magnetic Fe3O4@ZnO nanocomposite (NC) was successfully synthesized by a wet milling method using a high energy milling (HEM) machine. The magnetic Fe3O4@ZnO NC was characterized by an X-ray Diffractometer (XRD), scanning and transmission electron microscopes (SEM and TEM), and a vibrating sample magnetometer (VSM). X-ray diffraction results show that Fe3O4@ZnO NC consisted of ZnO and Fe3O4 phases. The microstructure analysis indicated that Fe3O4@ZnO NC presented a ZnO shell wrapped around the surface of a magnetic Fe3O4 surface. The average diameter of the aggregated Fe3O4 nanoparticle (NP) is 20 nm, while that of Fe3O4@ZnO NCs is nearly 30 nm. The Fe3O4 NP and Fe3O4@ZnO NC show typical superparamagnetic behavior with low coercivity. The saturation magnetization (Ms) of Fe3O4 NP was measured at about 66.26emu.g-1 and then declined to 34.79emu.g-1 after being encapsulated with a ZnO shell. The photoactivities of the Fe3O4@ZnO NC under UV irradiation were quantified by the degradation of a methylene blue (MB) dye solution. The result reveals that the photodegradation efficiency of Fe3O4@ZnO NC is favorable at pH neutral (pH = 7) reaching 100%. By increasing the MB dye concentration from 10 ppm to 40 ppm, the photodegradation efficiency decreases from 100% to 52%. The Fe3O4@ZnO NC can be easily collected by an external magnet. The magnetic Fe3O4@ZnO NC could be extended to various potential applications, such as purification processes, catalysis, separation, and photodegradation."
Depok: Faculty of Engineering, Universitas Indonesia, 2016
UI-IJTECH 7:3 (2016)
Artikel Jurnal  Universitas Indonesia Library
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Chairun Nisa
Aktivitas Anomali Geomagnetik pada Skala Ultra-low Frequency (ULF) di sekitar Stasiun Geomagnetik Sumedang, Jawa Barat = Geomagnetic Anomaly Activity on the Ultra-low Frequency (ULF) Scale around the Sumedang Geomagnetic Station, West Java
"Pulau Jawa berada di dekat zona subduksi Lempeng Eurasia dan Indo-Australia, yang menyebabkan terbentuknya patahan-patahan di daratan. Salah satu daerah yang terdampak adalah Kabupaten Sumedang, Jawa Barat. Prediksi gempabumi penting untuk meminimalisir kerusakan. Analisis aktivitas anomali geomagnetik Ultra-low Frequency (ULF) sebelum gempabumi dilakukan di sekitar stasiun geomagnetik TJS Sumedang menggunakan metode Polarization Ratio Analysis (PRA). Metode ini membandingkan nilai medan magnetik komponen vertikal terhadap horizontal (SZ/SG) berbasis Fast Fourier Transform (FFT) untuk mendeteksi anomali geomagnetik ULF (0.01 Hz - 0.04 Hz). Frekuensi ini dipilih karena mudah merambat ke permukaan, memungkinkan deteksi anomali yang jelas. Tiga gempabumi tahun 2020-2021 dengan magnitudo (M) ≥ 5 dan jarak episenter (R) ≤ 150 km (10 Maret 2020, M5; 25 Oktober 2020, M5.4; dan 27 April 2021, M5) dianalisis. Data geomagnetik malam hari komponen X, Y, dan Z dipilih untuk mengurangi noise. Hasil menunjukkan frekuensi 0.01 Hz - 0.04 Hz optimal mendeteksi prekursor gempa pada 27 April 2021. Anomali geomagnetik ULF tidak berkaitan dengan badai geomagnetik, dibuktikan dengan nilai indeks Dst (Disturbance storm time) yang tidak melebihi ambang batas.
Java Island is adjacent to the subduction zone of the Eurasian and Indo-Australian Plates, causing the formation of several faults on land. From the formation of faults that can be caused by earthquakes, there are areas that are affected, one of which is Sumedang Regency, West Java. Earthquake prediction efforts are very important to minimize the damage that will occur. Ultra-low Frequency (ULF) geomagnetic anomaly activity was analyzed before the earthquake around the TJS Sumedang geomagnetic station using the Polarization Ratio Analysis (PRA) method, which compares the magnetic field value of the vertical component to the horizontal component (SZ/SG) based on Fast Fourier Transform (FFT), which is used to convert data from the time domain into the frequency domain to see ULF scale geomagnetic anomaly activity from 0.01 Hz - 0.04 Hz because this frequency wave easily propagates to the surface, allowing clear anomaly detection. Three earthquakes in 2020-2021 taken at magnitude (M) ≥ 5 and earthquake epicenter (R) ≤ 150 km (EQ1 with M5 on March 10, 2020, EQ2 with M5.4 on October 25, 2020, and EQ3 with M5 on April 27, 2021) in the vicinity of the TJS Sumedang geomagnetic station were selected because the larger the M and the closer the R of the earthquake can strengthen the geomagnetic anomaly readings. Nighttime geomagnetic data of X, Y, and Z components were selected to reduce noise or human activity. The results showed that the frequency of 0.01 Hz - 0.04 Hz was optimal for detecting possible precursors of the M5 earthquake on April 27, 2021 (EQ1), and the ULF geomagnetic anomaly in this study was not related to geomagnetic storms, which was obtained from the Dst (Disturbance storm time) index value which did not exceed the threshold line."
Depok: Fakultas Matematika dan Ilmu Pengetahuan Alam Universitas Indonesia, 2024
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Angga Noviana Cahya Astuti
Green Synthesis dan Karakterisasi Nanokomposit TiO2/InVO4 Menggunakan Daun Mangga (Mangifera Indica L.) dan Aktivitas Fotokatalitiknya untuk Degradasi Rifampicin = Green Synthesis and Characterization of TiO2/InVO4 Nanocomposite Using Mango Leaves (Mangifera Indica L.) and Its Photocatalytic Activity for Rifampicin Degradation
"Pada penelitian ini, nanopartikel TiO2 telah dimodifikasi dengan InVO4 melalui metode green synthesis menggunakan ekstrak daun mangga (Mangifera indica L.). Ekstrak daun mangga fraksi air yang digunakan mengandung metabolit sekunder berupa alkaloid, saponin, tannin, dan polifenol yang berperan sebagai sumber basa lemah dan agen capping. Nanopartikel TiO2, InVO4, dan nanokomposit TiO2/InVO4 dikarakterisasi menggunakan FTIR, XRD, UV-Vis DRS, dan FESEM-EDS. Aktivitas fotokatalitik nanokomposit TiO2/InVO4 terhadap rifampicin di bawah iradiasi sinar tampak selama 120 menit diuji menggunakan spektrofotometer UV-Vis. Persentase fotodegradasi TiO2/InVO4 dengan massa optimum 8 mg menunjukkan persentase tertinggi yaitu 97,18% dibandingkan variasi kondisi lain yaitu katalis TiO2 (34,13%), InVO4 (74,93), adsorpsi (36,07%), dan fotolisis (12,43%). Serta kinetika reaksi fotokatalisis nanokomposit TiO2/InVO­4­ terhadap degradasi rifampicin mengikuti model pseudo orde satu dengan konstanta laju reaksi (k) sebesar 9,34 x 10-3 menit-1.
In this research, TiO2 nanoparticles were modified with InVO4 by means of green synthesis method using mango (Mangifera indica L.) leaf extract. The water fraction of mango leaf extract consisted of secondary metabolites such as alkaloids, saponins, tannins, and polyphenols which act as sources of weak base and capping agent. TiO2, InVO4, and TiO2/InVO4 nanocomposites were characterized using FTIR, XRD, UV-Vis DRS, and FESEM-EDS. The photocatalytic activity of TiO2/InVO4 nanocomposites against rifampicin under visible light irradiation for 120 minutes was probed by UV-Vis spectrophotometer. The percentage of degradation of TiO2/InVO4 with an optimum mass of 8 mg showed the highest percentage of 97,18% compared to other conditions, catalyst TiO2 (34,13%), InVO4 (74,93), adsorption (36,07%), and photolysis (12,43%). Also, kinetic photocatalytic reaction of TiO2/InVO4 on rifampicin degradation follows pseudo-first order with a reaction rate constant (k) of 9,34 x 10-3 minutes-1."
Depok: Fakultas Matematika dan Ilmu Pengetahuan Alam Universitas Indonesia, 2023
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Mamahit, Prisilia Irene
Green Synthesis dan Karakterisasi Nanokomposit ZnO/NiCr2O4 Menggunakan Ekstrak Daun Randu (Ceiba pentandra) dan Uji Aktivitas Fotokatalitiknya terhadap Rifampisin = Green Synthesis and Characterization of ZnO/NiCr2O4 Nanocomposite Using Randu Leaf Extract (Ceiba pentandra) and Its Photocatalytic Activity for Rifampicin
"Pada penelitian ini, nanopartikel ZnO, nanopartikel NiCr2O4, serta nanokomposit ZnO/NiCr2O4 berhasil untuk disintesis menggunakan metode green synthesis dengan ekstrak daun randu (Ceiba pentandra). Ekstrak daun randu mengandung senyawa metabolit sekunder yaitu alkaloid, saponin, dan polifenol, dibuktikan dengan karakterisasi FTIR dan spektroskopi UV-Vis. Alkaloid berperan sebagai sumber basa lemah, sedangkan saponin dan polifenol berperan sebagai capping agent dalam proses sintesis nanopartikel dan nanokomposit. Berdasarkan hasil dari karakterisasi menggunakan Spektrofotometer UV-Vis DRS, didapatkan nilai band gap dari nanopartikel ZnO, nanopartikel NiCr2O4, dan nanokomposit ZnO/NiCr2O4 berturut-turut adalah sebesar 3,0 eV, 1,95 eV, dan 2,63 eV. Hasil dari uji aktivitas fotokatalitik dari nanokomposit ZnO/NiCr2O4 terhadap larutan rifampisin selama 120 menit di bawah iradiasi sinar tampak menunjukkan nanokomposit ZnO/NiCr2O4 memiliki persentase fotodegradasi yang paling baik daripada nanopartikel ZnO dan nanopartikel NiCr2O4. Persentase fotodegradasi yang didapatkan dari nanopartikel ZnO, nanopartikel NiCr2O4, dan nanokomposit ZnO/NiCr2O4 berturut-turut adalah sebesar 12,25%, 42,37%, dan 97,37%. Kinetika reaksi untuk fotodegradasi nanokomposit ZnO/NiCr2O4 terhadap rifampisin mengikuti pseudo orde satu dengan tetapan laju sebesar 9,35 x 10-3 min-1.
In this research, ZnO nanoparticles, NiCr2O4 nanoparticles, and ZnO/NiCr2O4 nanocomposites have been successfully synthesized by means of green synthesis method using Randu (Ceiba pentandra) leaf extract. Randu leaf extract contains secondary metabolites, including saponins, and polyphenols, as evidenced by FTIR and UV-Vis spectroscopy. The alkaloids acted as a source of weak bases, while saponins and polyphenols acted as capping agents in the synthesis of nanoparticles and nanocomposite process. Based on DRS UV-Vis measurement results, the band gap values of ZnO nanoparticles, NiCr2O4 nanoparticles, and ZnO/NiCr2O4 nanocomposites were 3.0 eV, 1.95 eV, and 2.63 eV, respectively. Meanwhile, the results of the photocatalytic activity test of the ZnO/NiCr2O4 nanocomposites in rifampicin solution photodegradation for 120 minutes under visible light irradiation, showed that ZnO/NiCr2O4 nanocomposites had the best percentage of photodegradation than ZnO nanoparticles and NiCr2O4 nanoparticles. The degradation percentages of ZnO nanoparticles, NiCr2O4 nanoparticles, and ZnO/NiCr2O4 nanocomposites were 12.25%, 42.37%, and 97.37%, respectively. Reaction kinetics for photodegradation of ZnO/NiCr2O4 nanocomposites to rifampicin followed pseudo-first order model with the rate constant 9,35 x 10-3 min-1."
Depok: Fakultas Matematika dan Ilmu Pengetahuan Alam Universitas Indonesia, 2023
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Sitanggang, Ida Frisca Royani
Sintesis dan karakterisasi nanokomposit selulosa/Ag3PO4/ZnO untuk fotokatalisis degradasi metil jingga = Synthesis and characterization of cellulose/Ag3PO4/ZnO nanocomposite for photocatalytic degradation of methyl orange
"Nanokomposit selulosa/Ag3PO4/ZnO untuk fotokatalisis degradasi metil jingga telah disintesis dan dikarakterisasi menggunakan FTIR, XRD, UV-DRS dan SEM. Penambahan Ag3PO4 pada ZnO dapat menurunkan energi band gap ZnO dari 3.21 eV menjadi 3.19 eV. Pada penelitian ini, ZnO akan bertindak sebagai sisi aktif katalis, Ag3PO4 bertindak sebagai sensitizer yang dapat meningkatkan kemampuan katalis untuk menyerap sinar visible, sedangkan selulosa bertindak sebagai support katalis. Proses fotokatalisis degradasi metil jingga dilakukan di bawah sinar UV dan visible selama 1 jam. Kondisi optimum yang diperolah adalah ketika proses fotokatalisis dilakukan pada pH 6, menggunakan jumah katalis 45 mg, dengan rasio komposit pada ZnO/Ag3PO4 1:2, dan rasio selulosa pada nanokomposit selulosa/Ag3PO4/ZnO 1:2:1.  Nilai efisiensi fotodegradasi metil jingga yang paling tinggi adalah sebesar 81.05%. Reaksi ini mengikuti kinetika pseudo orde satu dan proses adsorpsi yang terjadi mengikuti model isoterm adsorpsi Langmuir.
Cellulose/Ag3PO4/ZnO nanocomposite for photocatalytic degradation of methyl orange have been synthesized and characterized by FTIR, XRD, UV-DRS, and SEM. The addition of Ag3PO4 to ZnO can reduce the band gap energy from 3.21 eV to 3.19 eV. In this work, ZnO acts as an active site, Ag3PO4 acts as sensitizer that can increase the ability of catalyst to absorb visible light, and cellulose acts as a catalyst support. The photocatalysis degradation of methyl orange was observe under UV and light illumination for an hour. The optimum condition obtained was when the photocatalyst was conducted at pH 6 using 45 mg catalyst with composite ratio ZnO/Ag3PO4 1:2, and cellulose ratio on cellulose/Ag3PO4/ZnO nano composite 1:2:1. The highest photodegradation efficiency of methyl orange is 81.05%. This reaction fits well to the pseudo-first order kinetics and Langmuir adsorption isotherm model."
Depok: Fakultas Matematika dan Ilmu Pengetahuan Alam Universitas Indonesia, 2020
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Rafi Ramadhan
Green Synthesis Nanokomposit ZnO/CeMnO3 menggunakan Ekstrak Daun Bayam Raja (Amaranthus viridis) dan Uji Aktivitas Fotokatalitiknya terhadap Degradasi Malasit Hijau = Green Synthesis ZnO/CeMnO3 Nanocomposite using Green Amaranth (Amaranthus viridis) Leaf Extract and The Photocatalytic Activity Test on Malachite Green Degradation
"Pada penelitian ini, sintesis nanokomposit ZnO/CeMnO3 dilakukan dengan metode green synthesis menggunakan ekstrak daun bayam raja (Amaranthus viridis). Metabolit sekunder pada ekstrak digunakan sebagai basa lemah dan capping agent dalam proses sintesis nanokomposit. Untuk mengidentifikasi sifat optik dan struktural nanopartikel serta nanokomposit, dilakukan dikarakterisasi dengan instrumen UV-Vis DRS, FTIR, XRD, Photoluminescence, SEM-EDX, dan HRTEM. Nanokomposit ZnO/CeMnO3 menunjukkan nilai band gap yang menurun dibanding ZnO, yaitu pada 2,68 eV. Selain itu, karakterisasi HRTEM mengkonfirmasi terbentuknya ZnO/CeMnO3 heterojunction dengan d spacing ZnO (110) = 0,162 nm dan d spacing CeMnO3 = 0,31 nm. Ukuran partikel rata-rata ZnO/CeMnO3 adalah 7,46 nm. Aktivitas fotokatalitik nanokomposit ZnO/CeMnO3 diuji untuk mendegradasi larutan malasit hijau di bawah sinar tampak selama 120 menit serta dibandingkan dengan aktivitas fotokatalitik nanopartikel ZnO dan CeMnO3. Persentase fotodegradasi malasit hijau oleh ZnO/CeMnO3, CeMnO3, dan ZnO masing-masing bernilai 92,69%; 69,46%; dan 37,5%. Kinetika reaksi fotodegradasi nanokomposit ZnO/CeMnO3 mengikuti model orde satu semu dengan konstanta laju senilai 1,031 x 10-2 min-1. Peningkatan aktivitas fotokatalitik nanokomposit ZnO/CeMnO3 disebabkan karena adanya penurunan bandgap ZnO dan rendahnya laju fotorekombinasi electron-hole yang masing-masing dibuktikan oleh analisis spektroskopi UV-Vis DRS dan photoluminescence.
In this study, ZnO/CeMnO3 nanocomposites were synthesized using green synthesis method using green amaranth leaf extract (Amaranthus viridis). The secondary metabolites present in the extract were utilized as a weak base and capping agent during the synthesis processes. To identify the optical and structural properties of the synthesized nanoparticles and nanocomposites, characterization was performed using UV-DRS, FTIR, XRD, Photoluminescence, SEM-EDX, and HRTEM instruments. The synthesized ZnO/CeMnO3 nanocomposite showed a decreased band gap value compared to ZnO, at 2,68 eV. Additionally, XRD and HRTEM characterization confirmed the formation of the ZnO/CeMnO3 composite on a nanometer scale with the average particle size at 7,46 nm. The photocatalytic activity of the ZnO/CeMnO3 nanocomposite was tested by degrading a malachite green solution under visible light for 120 minutes and compared with the photocatalytic activity of ZnO and CeMnO3 nanoparticles. The percentages of malachite green photodegradation by ZnO/CeMnO3, CeMnO3, and ZnO were 92,69%; 69,46%; and 37,5%, respectively. The photodegradation reaction kinetics of the ZnO/CeMnO3 nanocomposite were also determined to follow a pseudo-first-order model with a rate constant of 1.031 x 10-2 min-1. The increase in photocatalytic activity of the ZnO/CeMnO3 nanocomposite is due to a decrease in the bandgap and a low rate of electron-hole photorecombination which is proven by UV-Vis DRS and photoluminescence analysis respectively."
Depok: Fakultas Matematika dan Ilmu Pengetahuan Alam Universitas Indonesia, 2024
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Alisa Dwita Nabila
Sintesis Nanokomposit CuO-ZnCr2O4 Menggunakan Ekstrak Daun Kolesom (Talinum triangulare (Jacq.) Wild) dan Aplikasinya Fotokatalitiknya = Nanocomposites (Materials)Synthesis of CuO-ZnCr2O4 Nanocomposite using Kolesom Leaf Extract (Talinum Triangulare (Jacq.) Wild.) and its Photocatalytic Activity
"CuO-ZnCr2O4 berhasil disintesis menggunakan ekstrak daun Kolesom (EDK). Secara spesifik, alkaloid berperan sebagai sumber basa lemah untuk menghasilkan ion hidroksida dalam sintesis CuO-ZnCr2O4. Sedangkan saponin dan flavonoid digunakan sebagai capping agent untuk menstabilkan pembentukan partikel CuO-ZnCr2O4. Hasil sintesis nanopartikel CuO, nanopartikel ZnCr2O4, dan nanokomposit CuO-ZnCr2O4 dikarakterisasi menggunakan FTIR, UV-Vis DRS, XRD, dan FESEM. Setelah dikompositkan dengan CuO, nilai band gap ZnCr2O4 menurun dari 3,11 menjadi 2,92 eV, dimana diketahui band gap CuO sebesar 1,33 eV. Aktivitas fotokatalitik nanopartikel CuO, nanopartikel ZnCr2O4, dan nanokomposit CuO-ZnCr2O4 diuji untuk degradasi zat warna malasit hijau di bawah penyinaran sinar tampak. Fotokatalis menunjukkan efisiensi 88,45% untuk nanokomposit CuO-ZnCr2O4 pada massa optimum 7 mg dengan perbandingan konsentrasi CuO-ZnCr2O4 1:20 dalam waktu 120 menit diikuti dengan persentase degradasi CuO dan ZnCr2O4 sebesar 73,91% dan 52,76%. Khususnya, penelitian ini menawarkan metode yang ramah lingkungan dan sederhana untuk menyiapkan CuO-ZnCr2O4 sebagai fotokatalis yang menjanjikan.
CuO-ZnCr2O4 was successfully synthesized using Kolesom Leaf Extract (KLE). Specifically, alkaloids act as a source of weak bases to produce hydroxide ions in the synthesis of CuO-ZnCr2O4. Meanwhile, saponins and flavonoids were used as capping agents to stabilize the formation of CuO-ZnCr2O4 particles. The results of the synthesis of CuO nanoparticles, ZnCr2O4 nanoparticles, and CuO-ZnCr2O4 nanocomposites were characterized using FTIR, UV-Vis DRS, XRD, and FESEM. After being composited with CuO, the band gap value of ZnCr2O4 decreased from 3.11 to 2.92 eV, where it is known that the CuO band gap is 1.33 eV. The photocatalytic activity of CuO nanoparticles, ZnCr2O4 nanoparticles, and CuO-ZnCr2O4 nanocomposites were tested for the degradation of the green malachite dye under visible light irradiation. The photocatalyst showed an efficiency of 88.45% for CuO-ZnCr2O4 nanocomposite at an optimum mass of 7 mg with a concentration ratio of CuO-ZnCr2O4 1:20 in 120 minutes, followed by the percentage of CuO and ZnCr2O4 degradation of 73.91% and 52.76%, respectively. In particular, this study offers an environmentally friendly and simple method to prepare CuO-ZnCr2O4 as a promising photocatalyst."
Depok: Fakultas Matematika dan Ilmu Pengetahuan Alam Universitas Indonesia, 2022
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Ekky Febri Noor Hamzah
Sintesis nanokomposit ZnO/CuBi2O4 dalam sistem dua fasa menggunakan ekstrak justicia gendarussa Burm F. serta uji aktivitas fotokatalitiknya = Synthesis nanocomposite ZnO/CuBi2O4 in two-phase system using extract Justicia gendarussa Burm. F. and their photocatalytic activity
"Pada penelitian ini, nanopartikel ZnO dan CuBi2O4 serta nanokomposit ZnO/CuBi2O4 yang disintesis dengan metode green dengan menggunakan ekstrak dari Daun Gandarusa telah berhasil dilakukan. Penggunaan ekstrak tanaman (fasa heksana) ini dilakukan dengan memanfaatkan kandungan metabolit sekunder yang ada pada tanaman tersebut (alkaloid, sapponin) sebagai sumber basa lemah serta agen penstabil pada pembentukan nanopartikel. Pada metode pembentukannya, ditambahkan metode stirrer dengan kecepatan tinggi (High-Speed Stirring) untuk membentuk ukuran nanopartikel yang lebih kecil dengan waktu yang lebih singkat. Hasil karakterisasi dari XRD dari nanokomposit ZnO/CuBi2O4 menunjukkan kesesuaian pada 2θ yang khas dengan CuBi2O4 maupun ZnO. Nilai bandgap yang diperoleh dari hasil pengamatan UV-Vis DRS adalah sebesar 2,72 eV. Dari pengukuran FTIR, diketahui adanya ikatan Zn-O (ulur), Cu-O (ulur), dan Bi-O pada bilangan gelombang tertentu. Hasil karakterisasi TEM menunjukkan bahwa ukuran rata – rata nanokomposit ZnO/CuBi2O4 sebesar 59,164 ± 16,89 nm. Lalu, dari hasil pengujian terhadap aktivitas fotokatalitik ZnO, CuBi2O4 dan ZnO/CuBi2O4 yang dilakukan terhadap zat warna malachite green menghasilkan persen degradasi berturut-turut sebesar 62,48%, 82,69% dan 95,51%, dengan kinetika reaksi yang mengikuti reaksi pseudo-order 1.
In this research, synthesis of nanoparticle ZnO, CuBi2O4 and nanocomposite ZnO/CuBi2O4 with a novel-green method using extract Justicia gendarrussa Burm. F has been successfully done. Plant-Extract (hexane-phase) was used to take advantages of their secondary metabolites (alkaloid,saponin) as weak-source and also capping agent in a nanoparticles formation process. This method, also assisted with High-Speed Stirring to decreases nanoparticles size in shorter time. The XRD patterns of Nanocomposite ZnO/CuBi2O4 shows a match with 2θ of typical ZnO and CuBi2O4 from references. Nanocomposite ZnO/CuBi2O4 has a bandgap value 2,72 eV from UV-Vis DRS measurement. TEM characterization shows that size average of obtained Nanocomposite ZnO/CuBi2O4 is 59,164 ± 16,89 nm. Then, to evalute their photocatalytic activity, malachite green phodegradation modelling is used. The percentage of photodegradation value were obtained for ZnO, CuBi2O4 and ZnO/CuBi2O4 in a row, 62,48%, 82,69%, and 95,51% with the following reaction kinetics pseudo-order 1."
Depok: Fakultas Matematika dan Ilmu Pengetahuan Alam Universitas Indonesia, 2021
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Fristy Lita
Identifikasi anomali magnetik di daerah prospek panasbumi Arjuna - Welirang = Identification of magnetic anomalies on the geothermal prospects area Arjuna-Welirang
"Pengolahan data magnetik menghasilkan nilai magentik total yang telah dikoreksi oleh koreksi IGRF, Variasi Harian dan Koreksi Drift. Hasil pengolahan data kemudian diplot menjadi kontur anomali magnetik pada software SURFER 9.0. Dari kontur inilah kemudian didapatkan indikasi anomali magnetik pada data pengukuran. Anomali inilah yang nantinya akan dijadikan patokan untuk membuat permodelan. Permodelan menggunakan data magnetik bertujuan untuk mengidentifikasikan anomali magnetik yang terdapat pada data pengukuran. Anomali magnetik biasanya dipengaruhi oleh hot rock yang berada pada bawah permukaan. Pada penelitian ini, data magnetik yang digunakan adalah data pengukuran magnetik di daerah Arjuna-Welirang. Daerah prospek geothermal Arjuna-Welirang terletak di wilayah Kabupaten Malang, Kabupaten Mojokerto, Pasuruan, dan Kota Batu. Daerah prospek ini berada di lingkungan geologi yang didominasi oleh batuan vulkanik berumur kuarter.
Magnetic data processing give a magnetic total value that has been corrected by the correction IGRF, Diurnal Variety and Drift Correction. Then the data processing?s results are plotted into the contours of the magnetic anomalies in the software Surfer 9.0. This contour is then obtained an indication of magnetic anomalies on the measurement data. This is an anomaly that will be used as a benchmark for modeling. Modeling using magnetic data aims to identify magnetic anomalies are present in the measurement data. Magnetic anomalies are usually influenced by the hot rock that is on the bottom surface. In this study, which used magnetic data is the data of magnetic measurements in the Arjuna-Welirang. Geothermal prospect area Arjuna-Welirang located in Malang regency, regency Mojokerto, Pasuruan, and Batu. This prospect area is located in the geological environment which is dominated by old volcanic rocks quarter."
Depok: Fakultas Matematika dan Ilmu Pengetahuan Alam Universitas Indonesia, 2012
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Afifah Thahirah Muzakki
Sintesis, karakterisasi dan aktivitas katalitik dari nanokomposit tio2/cuo untuk mendegradasi methylene blue = Synthesis characterization and catalytic activity of tio2 cuo nanocomposite for degradation of methylene blue
"Nanokomposit TiO2/CuO dengan variasi rasio Cu/Ti disusun menggunakan metode sol-gel. Sampel komposit dikarakterisasi dengan X-Ray Diffraction, Energy Dispersive X-Ray Spectroscopy, Field Emission Scaning, Brunauer-Emmett-Teller, UV-Visible Diffuse Reflectance Spectroscopy dan Electronic Spin Resonance Spectroscopy. Methylene blue digunakan sebagai model pewarna tekstil untuk mengevaluasi fotokatalitik, sonokatalitik dan fotosonokatalitik. Difraksi sinar-X dan dispersif energi analisis X-ray menegaskan bahwa hanya struktur monoklinik CuO dan struktur anatase TiO2 yang muncul di nanokomposit TiO2/CuO. Degradasi methylene blue menunjukkan bahwa penggabungan CuO di nanokomposit TiO2/CuO menunjukkan aktivitas fotokatalitik yang cukup tinggi, dan energi cahaya yang dapat dimanfaatkan lebih banyak dibandingkan TiO2 murni. Selain itu, degradasi methylene blue juga diselidiki menggunakan sistem sonokatalisis dan sistem fotosonokatalisis.
Hasil penelitian menunjukkan bahwa semua data eksperimen mengikuti model pseudo-first order tapi laju konstanta fotosonokatalisis lebih tinggi dari proses fotokatalisis dan sonokatalisis individu masing-masing. Selain itu, kegiatan fotokatalitik, sonokatalitik dan fotosonokatalitik akan berkaitan dengan sifat struktural dan optik sampel. Mekanisme kegiatan katalitik akan dibahas.
TiO2/CuO nanocomposite with different Cu/Ti ratios were prepared using sol-gel method. The obtained composite samples were characterized with X-Ray Diffraction, Energy Dispersive X-Ray Spectroscopy, Field Emission Scaning, Brunauer-Emmett-Teller, UV-Visible Diffuse Reflectance Spectroscopy and Electronic Spin Resonance Spectroscopy. Methylene blue was used as a model of textile dye to evaluate their photocatalytic, sonocatalytic and photosonocatalytic activities. X-ray diffraction and energy dispersive X-ray analysis confirmed that only monoclinic CuO and anatase TiO2 structures are present in TiO2/CuO nanocomposites. The degradation of methylene blue indicated that the incorporation of CuO in TiO2/CuO nanocomposite exhibited an appreciable higher photocatalytic activity, and more light energy could be utilized than pure TiO2. In addition, the degradation of methylene blue was also investigated using sonocatalysis and photosonocatalysis systems.
The results showed that all experimental data followed the pseudo-first order model but the rate constant of the sonophotocatalysis is higher than the respective individual photocatalysis and sonocatalysis process. Furthermore, the photocatalytic, sonocatalytic and photosonocatalytic activities will be related to their structural and optical properties. The mechanism of catalytic activities will be discussed."
Depok: Fakultas Matematika dan Ilmu Pengetahuan Alam Universitas Indonesia, 2016
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