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Abstrak :
Nanohybrid iron oxide titanium dioxide copper oxide dengan tiga variasi molar 1 1 1 1 3 1 dan 1 5 1 telah disintesis menggunakan metode sol gel Pengukuran X Ray Diffraction XRD Field Emission Scanning Electron Microscopy FESEM Energy Dispersive X rays EDX UV Vis Spectroscopy dan Vibrating Sample Magnetometer VSM digunakan untuk menentukan sifat struktur morfologi nilai energy gap optik dan sifat magnetik dari sampel nanohybrid Pengujian aktivitas fotokatalitik sampel nanohybrid dilakukan dengan mengamati degradasi warna methylene blue MB dibawah pemaparan cahaya ultraviolet dan tampak Hasil menunjukkan keberadaan copper oxide seiring dengan peningkatan rasio molar titanium dioxide mempengaruhi aktivitas fotokatalitik nanohybrid Nanohybrid dengan rasio molar 1 5 1 menunjukkan aktivitas fotokatalitik yang paling baik untuk pemaparan dengan cahaya ultraviolet sedangkan untuk pemaparan dengan cahaya tampak didapatkan dengan rasio molar 1 1 1 Selain itu fotokatalis nanohybird dapat dipisahkan setelah proses reaksi menggunakan magnet eksternal Penambahan scavenger menunjukkan hole memiliki peranan penting dalam proses degradasi methylene blue ......Iron oxide titanium dioxide copper oxide nanohybrids with three different molar ratios 1 1 1 1 3 1 and 1 5 1 were successfully prepared by sol gel method X Ray Diffraction XRD Field Emission Scanning Electron Microscopy FESEM Energy Dispersive X rays EDX UV ndash Vis spectroscopy and Vibrating Sample Magnetometer VSM techniques were employed to determine the structure morphology optical gap energy and magnetic properties of the as prepared samples Photocatalytic examination of the nanohybrids was carried out using aqueous solution of methylene blue MB under ultraviolet and visible light irradiation The results demonstrate that the increase molar ratio of titanium dioxide and the addition of copper oxide to iron oxide titanium dioxide cooper oxide has remarkable influence on the photocatalytic activity The nanohybrids with 1 5 1 molar ratio has superior activity in degradation of MB under ultraviolet light while under visible light the maximum degradation is reached by sample with molar ratio 1 1 1 Furthermore the photocatalysts can be separated from the reaction system simply by applying an external magnetic Active species on photocatalytic activity were investigated by measuring the photocatalytic degradation in the presence of scavenger The results suggested that holes play the most important role in degradation of methylene blue.

Abstrak :
Photocatalytic degradsi Ibuprofen dalam larutan air dilakukan dengan menggunakan ion besi sebagai activator persulfat (PS) pada cahaya tampak. Nanopartikel hematite disintesis dengan menggunakan metode hidrotermal. Pada penelitian ini, tiga variasi weight percent graphene ditambahkan pada nanopartikel hematite untuk mendapatkan performa katalitik terbaik. Katalis nanokomposit dengan sepuluh wight percent graphene menunjukkan performa katalitik terbaik, kemudian katalis ini ditambahkan dengan dua variasi weight percent perak. Seluruh material kemudian dikarakterisasi dengan X-ray Diffraction (XRD), Thermal Gravimetric Analysis (TGA), X-ray Fluorescence (XRF), Raman, UV-Vis DRS dan BET. Proses degradasi diamati dibawah parameter eksperimen yang berbeda, seperti konsentrasi awal dan pH. Performa katalitik terbaik diperoleh pada konsentrasi IBP dan pH yang rendah. Peningkatan kosentrasi PS dan dosis katalis juga menunjukkan tingkat degradasi optimum. Nanokomposit Ag/Fe2O3/Graphene memiliki tingkat degradsi yang lebih baik daripada hematite/Graphene dan nanopartikel hematite. Hasil uji scavenger menunjukkan bahwa elektron merupakan spesies aktif dalam proses fotokatalitik ini. ......­Ibuprofen photocatalytic degradation in the aqueous solution was carried out using Iron ions as persulfate (PS) activators under visible light irradiation. Hematite nanoparticle was synthesized using hydrothermal method. In this study, three variations of the graphene weight percent were added to nanoparticles to obtain the nanocomposite’s best photocatalytic performance. The nanocomposite catalyst with ten weight percent graphene showed the best photocatalytic performance, then this catalyst was added with two weight percent variations of silver. All materials were then characterized by X-ray Diffraction (XRD), Thermal Gravimetric Analysis (TGA), X-ray Fluorescence (XRF), Raman, UV-Vis DRS and BET. The degradation was investigated under different experimental parameters such as initial dye concentration and pH. The best photocatalytic performance was obtained at low Ibuprofen concentration and pH. An increase in PS concentration and catalyst dosage indicates the optimum degradation rate. Ag/hematite/graphene nanocomposite gives a better degradation rate than the hematite/graphene and hematite nanoparticle. Scavenger result showed that electrons are the active species in the photocatalytic process.

Abstrak :
Pb doped ZnO disintesis dengan metode kopresipitasi menggunakan prekursor ZnSO4.7H2O dan PbCl2 dengan variasi konsentrasi dopant Pb (0.5%, 3%, 3.5% dan 5%) pada kondisi pH 13 serta temperatur pengeringan 100 0C selama empat jam. Sampel dikarakterisasi dengan X-Ray Diffraction (XRD) dan Energy Dispersive X-Ray (EDX) untuk melihat morfologi serta komposisi Pb doped ZnO. Hasil karakterisasi XRD menunjukkan terbentuknya fase utama wurtzite ZnO serta ditemukan fase sekunder PbO. Analisa lebih lanjut menunjukkan perubahan parameter kisi wurtzite ZnO (a=3.252, c=5.216) serta penurunan ukuran kristal (18 hingga 12 nm) dengan penambahan dopant Pb. Sifat optik Pb doped ZnO dikarakterisasi menggunakan UV-Vis Spectroscopy dan diperoleh penurunan energi celah pita ZnO (3.379 hingga 3.310 eV). Penurunan energi celah pita ZnO mengindikasikan terbentuknya pita tambahan di bawah pita konduksi ketika terjadi substitusi Pb ke dalam matriks ZnO. Kemampuan fotokatalis Pb doped ZnO dikarakterisasi dengan metode Photocatalytic Activity (PCA) menggunakan sinar UV pada rentang 200–800 nm selama 1 jam dan didapatkan efisiensi fotokatalis terbaik pada sampel Pb doped ZnO dengan kadar dopant 3.5%. ......Pb doped ZnO were synthesized by coprecipitation with ZnSO4.7H2O and PbCl2 (0.5%, 3%, 3.5% and 5%) at pH 13 and 100 0C for four hours. Morphology and composition of Pb doped ZnO were characterized by X-Ray Diffraction (XRD) and Energy dispersive X-ray (EDX). XRD spectrum indicated the formation of wurtzite ZnO and PbO. Further analysis showed that lattice parameter of ZnO has changed (a = 3.252, c = 5.216) and crystallite size has decreased (18 to 12 nm) with the addition of Pb. The optical properties of Pb doped ZnO were characterized using UV-Vis spectroscopy and showed that bandgap energy was decreased (3.379 to 3.310 eV). This indicated the formation of additional bandgap below the conduction band when the substitution of Pb into the ZnO matrix. Photocatalytic Activity (PCA) of Pb doped ZnO photocatalysts were characterized using UV in 200-800 nm for 1 hour and Pb Doped ZnO 3.5% has the best photocatalytic activity.

Abstrak :
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.

Abstrak :
Nanopartikel ZnO yang dimodifikasi oleh CTAB dan didop dengan empat variasi konsentrasi atom Ni berhasil dibuat melalui metode kopresipitasi. Seluruh sampel dikarakterisasi oleh pengukuran energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), fourier transform infrared (FTIR) spectroscopy, electron spin resonance (ESR), field emission scanning electron microscope (FESEM), dan UV-Vis spectrophotometry. Hasil pengukuran memperlihatkan bahwa penambahan CTAB dan konsentrasi atom dopant mempengaruhi morfologi dan sifat optik dari seluruh sampel. Pengujian aktivitas fotokatalitik sampel dilakukan pada larutan methyl orange (MO) dan methylene blue (MB) di bawah paparan sinar UV selama 2 jam. Hasil yang diperoleh menunjukkan bahwa efisiensi kinerja degradasi fotokatalitik dari sampel meningkat seiring dengan bertambahnya konsentrasi atom dopant. ...... CTAB-modified ZnO nanoparticles doped with four different concentrations of Ni were successfully synthesized by co-precipitation method. All samples were characterized using energy dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), fourier transform infrared (FTIR) spectroscopy, electron spin resonance (ESR), field emission scanning electron microscope (FESEM), and UV-Vis spectrophotometry. The results demonstrated that the addition of CTAB and doping concentration affect the morphology and optical properties of the samples. The photocatalytic activity test of all samples was studied by observing the degradation of methyl orange (MO) and methylene blue (MB) under UV light irradiation. The result indicates that the performance of photocatalytic activity from all samples increases along with the increasing concentration of atomic dopant.

Abstrak :
Nanopartikel ZnO:Fe/SDS dengan empat variasi konsentrasi Fe telah disintesis menggunakan metode kopresipitasi. Struktur dan sifat optis dari nanopartikel dikarakterisasi menggunakan Energy Dispersive X-Ray (EDX), X-Ray Difraction (XRD), Electron Spin Resonance (ESR), Field Emision - Scanning Electron Microscope (FESEM), Fourier Transform-Infrared (FTIR), dan spektroskopi UV-Vis. Aktivitas fotokatalitik nanopartikel diuji melalui degradasi Methyl Orange (MO) dan Methylene Blue (MB) di bawah sinar UV. Nanopartikel yang diperoleh memiliki fase tunggal dengan struktur heksagonal wurtzite. Untuk konsentrasi dopan 11 at. % terdapat fase tambahan berupa ZnFe2O4 yang menunjukkan batas solubilitas Fe dalam menggantikan Zn pada kisi ZnO. Aktivitas fotokatalitik mengalami peningkatan saat konsentrasi Fe meningkat berkaitan dengan terbentuknya trapping site di gap nanopartikel. Nanopartikel ZnO:Fe/SDS menunjukkan aktivitas fotokatalitik yang lebih tinggi dalam mendegradasi MB dibandingkan MO berkaitan dengan interaksi elektrostatik antara SDS dan dyes. ......ZnO:Fe/SDS nanoparticles with four varies of Fe concentration were prepared by coprecipitation methods. Structural and optical properties of nanoparticles were characterized using Energy Dispersive X-Ray (EDX), X-Ray Difraction (XRD), Electron Spin Resonance (ESR), Field Emision - Scanning Electron Microscope (FE-SEM), Fourier Transform-Infrared (FTIR), and UV-Vis Spectroscopy. The photocatalytic activity were evaluated by observing the photodegradation of Methyl Orange (MO) and Methylene Blue (MB) under UV light irradiation. The nanoparticles had single phases with hexagonal wurtzite structure. Sample ZnO:Fe/SDS 11 at. % showed the secondary phase of ZnFe2O4 which shown the solubility limit of Fe subtituted Zn in ZnO system. The photocatalytic of nanoparticles increased as the Fe doping concentration increased due to forming trapping site in band gap. ZnO:Fe/SDS nanoparticles showed higher photocatalytic activity in photodegradation of MB than MO due to electrostatic forced between SDS and dyes.

Abstrak :
ZnO:Co/SDS dengan variasi konsentrasi dopant 3 - 13 at% disintesis menggunakan metode kopresipitasi Komposisi sampel dan keberadan dopant Co serta SDS diuji menggunakan spektroskopi Energy Dispersive X Ray EDX Fourier Transform Infrared FTIR dan Electron Spin Resonance ESR Pengaruh dopant dan SDS terhadap struktur kristal ZnO diuji melalui pengukuran X Ray Diffraction XRD Keempat sampel menunjukkan struktur hexagonal wurtzite Fase sekunder Zn OH 2 terdeteksi pada sampel ZnO Co SDS 13 at Pengujian Field Emission Scanning Electron Microscopy FESEM menunjukkan sampel yang disintesis memiliki bentuk menyerupai lembaran Pengaruh dopant dan SDS terhadap sifat optis sampel diuji melalui spektroskopi UV Vis Diffuse Reflectance UV Vis Analisis spektrum UV Vis dengan fungsi Kubelka Munk menunjukkan nilai energy gap sampel menurun dengan peningkatan konsentrasi dopant Aktivitas fotokatalitik sampel diuji dengan mengamati degradasi warna pada larutan uji metil jingga MO dan metilen biru MB Sampel mampu mendegradasi MO sebanyak 85 dan MB sebanyak 89 dengan pemaparan sinar Ultraviolet 200 nm selama 2 jam Spesies utama dalam proses fotodegradasi diuji dengan menambahkan scavenger pada larutan uji Pada sistem ini diketahui pengaruh elektron e hole h gugus radikal hidroksil OH. ...... ZnO:Co/SDS with doping concentration varies between 3 ? 13 at% were synthesized by co-precipitation method. Sample composition also dopant and SDS existence characterized by Energy Dispersive X-Ray (EDX), Fourier Transform Infrared (FTIR), and Electron Spin Resonance (ESR) spectroscopy. The effect of dopant and SDS to crystal structure of ZnO were examined by X-Ray Diffraction (XRD). All samples shown hexagonal wurtzite structure. Secondary phase of Zn(OH)2 were detected at ZnO:Co/SDS 13 at%. Field Emission Scanning Electron Microscopy (FESEM) measurement shown the as synthesized samples has nanosheet-like shape. Dopant and SDS effect to optical properties observed by UVVis Diffuse Reflectance (UV-Vis DRS) spectroscopy. UV-Vis reflectance spekctrum were analyzed by Kubelka-Munk relation, it is shown the energy gap of samples decreased as the doping concentration increased. Photocatalytic activity of samples were tested by observing the degradation of methyl orange (MO) and methylene blue (MB) as dyes model. Under Ultraviolet irradiation (200 nm) irradiation for 2h, samples were able to degrade MO to 85% and MB to 89%. Main species in photodegradation mechanism tested by adding scavenger. It is shown the effect of electron (e-)> hole (h+)> hydroxyl radical species (OH-).

Abstrak :
Pada penelitian, ini dilakukan sintesis nanopartikel ZnO, nanopartikel CeCuO3, dan nanokomposit ZnO/CeCuO3 secara green synthesis menggunakan ekstrak daun bunga matahari (Helianthus annuus L.). Daun bunga matahari mengandung alkaloid yang dapat berperan sebagai basa lemah (ditandai dengan adanya reaksi positif terhadap reagen Wagner) dan mengandung saponin (ditandai dengan adanya reaksi positif terhadap akuades) yang berperan sebagai capping agent pada sintesis nanopartikel dan nanokomposit. Keberhasilan sintesis nanopartikel ZnO, nanopartikel CeCuO3, dan nanokomposit ZnO/CeCuO3 dibuktikan dengan identifikasi struktur yang bersesuaian dengan referensi pada pengujian FTIR dan diperkuat dengan adanya kesesuaian nanopartikel dan nanokomposit yang disintesis dengan database pada karakterisasi menggunakan XRD. Pengkompositan ZnO dengan CeCuO3 dilakukan untuk meningkatkan aktivitas fotokatalitik ZnO di bawah iradiasi sinar tampak dengan menurunkan energi celah pita ZnO. Hal ini dinyatakan pada karakterisasi menggunakan UV-Vis DRS bahwa energi celah pita ZnO, CeCuO3, dan ZnO/CeCuO3 secara berturut - turut sebesar 3,17 eV; 2,60 eV; dan 2,96 eV. Kemudian menghasilkan persentase fotodegradasi yang dihasilkan ZnO/CeCuO sebesar 91% lebih tinggi dibandingkan dengan aktivitas ZnO, yaitu sebesar 56% dan CeCuO3 sebesar 76%. Serta kinetika reaksi fotokatalisis nanokomposit ZnO/CeCuO3 terhadap malasit hijau mengikuti model pseudo orde satu dengan konstanta laju reaksi (k) sebesar 1,85 x 10-2 m-1. ......In this research, synthesis of ZnO nanoparticles, CeCuO3 nanoparticles, and ZnO/CeCuO3 nanocomposites was carried out by means of green synthesis using sunflower (Helianthus annuus L.) leaf extract. Sunflower leaves contain alkaloids which can act as weak bases (indicated by a positive reaction to Wagner's reagent) and contain saponins (indicated by a positive reaction to aquades) which act as capping agents in the synthesis of nanoparticles and nanocomposites. The successful synthesis of ZnO nanoparticles, CeCuO3 nanoparticles, and ZnO/CeCuO3 nanocomposites was proven by the identification of structures that matched the references in FTIR characterization and was strengthened by the suitability of the synthesized nanoparticles and nanocomposites with the database on characterization using XRD. Compositing of ZnO with CeCuO3 was carried out to increase the photocatalytic activity of ZnO under visible light irradiation by reducing the band gap of ZnO. This was stated in the characterization using UV-Vis DRS that the band gaps of ZnO, CeCuO3, and ZnO/CeCuO3 were respectively 3.17 eV; 2.60 eV; and 2.96 eV. Then the photodegradation percentage produced by ZnO/CeCuO3 was 91%, higher than the ZnO activity, which was 56% and CeCuO3, which was 76%. Also, the reaction kinetics of the ZnO/CeCuO3 nanocomposite photocatalyst for green malachite follows a pseudo-first-order model with a reaction rate constant (k) of 1.85 x 10-2 m-1.