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"Pencemaran lingkungan adalah salah satu masalah serius disebabkan pembuangan limbah berbahaya dan beracun dari industri–industri yang tidak teregulasi. Salah satu material yang banyak digunakan sebagai zat warna adalah sunset yellow pada industri tekstil yang berdampak buruk, menyebabkan risiko kesehatan seperti depresi, kerusakan ginjal, kerusakan hati, dan kanker. Pada penelitian ini telah dilakukan sintesis nanokomposit Nanochitosan/Fe₃O₄−SrSnO₃ untuk mendegradasi zat warna sunset yellow. Nankomposit Nanochitosan/Fe₃O₄−SrSnO₃ dikarakterisasi dengan Fourier–transform infrared spectroscopy (FTIR), ultraviolet–visible (UV–Vis), X–ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high–resolution transmission electron microscopy (HRTEM), Brunauer–Emmet–Teller (BET) dan ultraviolet visible–diffuse reflectance (UV–DRS). Pengaruh Fe₃O₄ terhadap sisi aktif SrSnO₃ telah dipelajari dan energi celah pita dari SrSnO₃ menjadi 2,4 eV dengan komposisi Fe₃O₄/SrSnO₃ (3:1) dengan persen degradasi sebesar 88,45% . Nanochitosan ditambahkan sebagai support meningkatkan aktivitas dari nanokomposit Fe₃O₄−SrSnO₃ dengan persen dgradasi 97,42%. Nanokomposit yang optimal yang digunakan untuk analisis kinetika reaksi dan isoterm adsorpsi adalah dengan kondisi massa 0,04 gram, pH 10, dan waktu selama 75 menit. Kinetika reaksi mengikuti psuedo first order dengan konstanta laju reaksi 0,058 dan sesuai dengan isoterm adsorpsi Langmuir

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Environmental pollution is one of the most serious problems caused by the disposal of hazardous and toxic waste from unregulated industries. One material that is widely used as a dye is sunset yellow in the textile industry which has adverse effects, causing health risks such as depression, kidney damage, liver damage, and cancer. In this study, Nanochitosan/ Fe₃O₄−SrSnO₃ nanocomposite has been synthesized to degrade sunset yellow dye. Nanochitosan/ Fe₃O₄−SrSnO₃ nanocomposites were characterized by Fourier-transform infrared spectroscopy (FTIR), ultraviolet-visible (UV-Vis), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), Brunauer-Emmet-Teller (BET) and ultraviolet visible-diffuse reflectance (UV-DRS). The effect of Fe3O4 on the active side of SrSnO₃ was studied and the band gap energy of SrSnO₃ became 2.4 eV with Fe₃O₄/SrSnO₃ composition (3:1) with a percent degradation of 88.45%. Nanochitosan added as support increases the activity of Fe₃O₄−SrSnO₃ nanocomposite with 97.42% degradation percent. The optimal nanocomposite used for the analysis of reaction kinetics and adsorption isotherms was with a mass condition of 0.04 grams, pH 10, and time for 75 minutes. The reaction kinetics followed first order psuedo with a reaction rate constant of 0.058 and fit the Langmuir adsorption isotherm."

"Dalam penelitian ini, sintesis hijau nanopartikel SiO2, nanopartikel NiFe2O4, dan nanocomposites SiO2 / NiFe2O4 dalam sistem dua fase (hexane-water) berhasil dilakukan menggunakan ekstrak daun tahongai (Kleinhovia hospita L.). Alkaloid sebagai metabolit sekunder digunakan sebagai sumber basa (-OH), sedangkan saponin digunakan sebagai agen penutup. Sintesis nanopartikel SiO2 yang berhasil, nanopartikel NiFe2O4, dan nanokomposit SiO2 / NiFe2O4 dikonfirmasi melalui hasil karakterisasi. Karakterisasi XRD membuktikan bahwa nanopartikel SiO2 memiliki struktur amorf, nanopartikel NiFe2O4 memiliki struktur spinel kubik, dan nanokomposit SiO2 / NiFe2O4 memiliki nilai difraksi gabungan 2 combined yang khas. Karakterisasi TEM menunjukkan ukuran rata-rata nanokomposit SiO2 / NiFe2O4 sebesar 10 nm. Aktivitas katalitik nanokomposit SiO2 / NiFe2O4 lebih tinggi dari nanopartikel SiO2 dan nanopartikel NiFe2O4 dengan persentase reduksi masing-masing 95,68%, 29,75%, dan 79,79% selama 30 menit. Berdasarkan perhitungan kinetika reaksi reduksi 4-Nitroanilin terhadap p-phenylenediamine menunjukkan bahwa nanokomposit SiO2 / NiFe2O4 mengikuti kinetika orde satu semu.

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In this research green synthesis of SiO2 nanoparticles, NiFe2O4 nanoparticles, and SiO2 / NiFe2O4 nanocomposites in a 2 phase (hexane-water) system was successfully carried out using a tahongai (Kleinhovia hospita L.) leaf extract. The secondary metabolite compound, the alkaloid, is used as a hydrolyzing agent (base source -OH), while saponin is used as a stabilizing agent (capping agent). The success of synthesis of SiO2 nanoparticles, NiFe2O4 nanoparticles, and SiO2 / NiFe2O4 nanocomposites was confirmed through the results of characterization. XRD characterization proves that SiO2 nanoparticles have an amorphous structure, NiFe2O4 nanoparticles have a cubic spinel structure, and SiO2 / NiFe2O4 nanocomposites have a diffraction value of 2θ typical of the two combined. TEM characterization shows the average size of SiO2 / NiFe2O4 nanocomposites is 10 nm. The catalytic activity test of SiO2 nanoparticles, NiFe2O4 nanoparticles, and SiO2 / NiFe2O4 nanocomposites as reduction catalysts were carried out on 4-Nitroaniline with NaBH4 as a reducing agent. The catalytic activity of SiO2 / NiFe2O4 nanocomposite was higher than SiO2 nanoparticles and NiFe2O4 nanoparticles with reduction percentage of 95.68%, 29.75% and 79.79% for 30 minutes, respectively. Based on the kinetics calculation, the rate of reduction of 4-Nitroaniline to p-phenylendiamine was found that the SiO2 / NiFe2O4 nanocomposite followed the pseudo first order reaction kinetics."

"Pada penelitian ini, nanopartikel ZnO, NiWO4, dan ZnO/NiWO4 berhasil disintesis dengan cara metode green synthesis menggunakan ekstrak daun alpukat (Persea americana) dalam sistem satu fasa. Kandungan ekstrak air daun alpukat adalah alkaloid, saponin dan polifenol. Nanopartikel ZnO, NiWO4, dan ZnO/NiWO4 dikarakterisasi menggunakan spektrofotometer Ultraviolet-Visible Diffuse Reflectance Spectroscopy (UV-Vis DRS), X-Ray Diffraction (XRD), Fourier Transform InfraRed (FTIR), Transmission Electron Microscopy (TEM) dan Scanning Electron Microscopy Energy Disperse X-Ray (SEM-EDX). Hasil karakterisasi UV-Vis DRS, nanopartikel ZnO, NiWO4, dan ZnO/NiWO4 memiliki band gap 3,15 eV, 2,35 eV, dan 3,03 eV. Hasil uji aktivitas fotokatilitiknya menggunakan nanokomposit ZnO/NiWO4 terhadap malasit hijau dibawah iradiasi sinar tampak selama 2 jam memiliki persen degradasi tertinggi dibandingkan dengan NiWO4 dan ZnO. Persen degradasi ZnO/NiWO4, NiWO4, ZnO adalah 96,20%, 79,22%, 48,30%.

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In this research, ZnO, NiWO4, and ZnO/NiWO4 nanoparticles were successfully synthesized by means of green synthesis method using avocado (Persea americana) leaf extract in a single phase system. The secondary metabolites of avocado leaf water extract are alkaloids, saponins and polyphenols. ZnO, NiWO4, and ZnO/NiWO4 nanoparticles were characterized using a spectrophotometer Ultraviolet-Visible Diffuse Reflectance Spectroscopy (UV-Vis DRS), X-Ray Diffraction (XRD), Fourier Transform InfraRed (FTIR), Transmission Electron Microscopy (TEM) and Scanning Energy Microscopy Electron Disperse X-Ray (SEM-EDX). The results of the photocathylytic activity test using the ZnO/NiWO4 nanocomposite against malachite green under visible light irradiation for 2 hours had the highest degradation percent compared to NiWO4 and ZnO. The degradation percentages of ZnO/NiWO4, NiWO4, ZnO were 96.81%, 79.71%, 51.38%."

"Nanokomposit Perak, Titanium dioksida, dan Mangan (II,III) oksida (Ag/TiO2/Mn3O4) dengan berbagai rasio molar telah disintesis menggunakan metode hidrotermal. Pengukuran difraksi sinar-X (XRD) mengkonfirmasi struktur nanokomposit Ag/TiO2/Mn3O4 yang terdiri dari struktur kubik Ag, TiO2 anatase, dan Mn3O4 tetragonal. Rasio komposisi unsur nanokomposit Ag/TiO2/Mn3O4 diselidiki dengan fluoresensi sinar-X (XRF). Efek sinergis Ag, TiO2 dan Mn3O4 dapat meningkatkan efisiensi nanokomposit sebagai fotokatalis. Peningkatan efisiensi ditunjukkan dengan melebarnya rentang absorbansi pada hasil pengukuran UV-Vis Diffuse Reflectance. Pengukuran adsorpsi-desorpsi nitrogen menunjukkan bahwa penambahan geraham TiO2 mengakibatkan penurunan luas permukaan spesifik nanokomposit Ag/TiO2/Mn3O4, sedangkan hasil sebaliknya diberikan dengan penambahan geraham Mn3O4. Pada uji fotokatalitik, hasil terbaik ditunjukkan oleh nanokomposit Ag/TiO2/Mn3O4 dengan dominasi Mn3O4 untuk radiasi UV dan cahaya tampak. Pada kondisi optimum, nanokomposit Ag/TiO2/Mn3O4 mampu mendegradasi metilen biru hingga 91% dengan penyinaran selama 2 jam. Uji scavenger mengidentifikasi lubang sebagai spesies yang berkontribusi paling besar pada proses fotokatalitik ini. Uji reusabilitas dan stabilitas pada nanokomposit Ag/TiO2/Mn3O4 menunjukkan hasil positif.

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Silver, Titanium dioxide, and Manganese (II,III) oxide (Ag/TiO2/Mn3O4) nanocomposites with various molar ratios have been synthesized using the hydrothermal method. X-ray diffraction (XRD) measurements confirmed the structure of the Ag/TiO2/Mn3O4 nanocomposite consisting of a cubic structure of Ag, TiO2 anatase, and tetragonal Mn3O4. The elemental composition ratio of Ag/TiO2/Mn3O4 nanocomposite was investigated by X-ray fluorescence (XRF). The synergistic effect of Ag, TiO2 and Mn3O4 can increase the efficiency of nanocomposites as photocatalysts. The increase in efficiency is indicated by the widening of the absorbance range on the measurement results of UV-Vis Diffuse Reflectance. The nitrogen adsorption-desorption measurements showed that the addition of TiO2 molars resulted in a decrease in the specific surface area of ​​the Ag/TiO2/Mn3O4 nanocomposite, while the opposite result was given by the addition of Mn3O4 molars. In the photocatalytic test, the best results were shown by the Ag/TiO2/Mn3O4 nanocomposite with the dominance of Mn3O4 for UV radiation and visible light. Under optimum conditions, Ag/TiO2/Mn3O4 nanocomposite was able to degrade methylene blue up to 91% with irradiation for 2 hours. The scavenger test identified pits as the species that contributed most to this photocatalytic process. Reusability and stability tests on Ag/TiO2/Mn3O4 nanocomposites showed positive results."

"Epoxy-organo clay nanocomposite materials are constructed from a polymer as a matrix and an organoclay as filler. Epoxy-organo clay nanocomposites have been synthesized using various curing agents. The aim of this research was to study the influence of the curing agent and the organoclay contents to the structure and mechanical properties of nanocomposites materials. Epoxy-organo clay nanocomposites were synthesized using cycloaliphatic amine as a curing agent and a montmorillonite organoclay (MMT) as filler through an in situ polymerization method. XRD and TEM technique provide more detail information to understand the structure that relates to the mechanical properties of the materials. Tensile test, compressive test and hardness test were conducted based on ASTM and JIS standards. The fracture surfaces after tensile tests were analyzed using SEM. The nanocomposite properties were compared to glass-fiber composites which were synthesized using wet-laminating method.It was found that the curing agent is influence to the nanocomposites structure which was shown by the change of d-spacing before and after the addition of the agent curing. XRD and TEM techniques showed that both intercalated and exfoliated structure have been formed. TEM image also exhibited that the number of intercalated structure was higher when the organoclay content was higher. It can be said that TEM techniques provides a better understanding of the nanocomposites structure and the number intercalated structure increase as the organoclay increases.The organoclay contain also influences to mechanical properties of nanocomposite materials. The addition of 10.5 wt.% organoclay improved the tensile modulus by 185% but and decreased tensile strength by 186% and 49%, and these values are lower of 36% and 90% compared to glass fiber composites. These decreases in the strength may be attributed to the fact that agglomerate and void was formed. From compression test, the addition of 3.1 wt.% organoclay demonstrated a 102% increase in compression strength and a 93% increase in load maximum compare to epoxy resin. But, that compression strength value lower of 11% compared to glass fiber composites. For the maximum load, the addition of 3.1 wt.% organoclay improved 246% compared to glass fiber composites. Addition of 7.3 wt.% organoclay demonstrated an increase of modulus of the epoxy resin by 93% and 2% compare to glass fiber composites. Meanwhile, the addition of 10.5% organoclay cause decreasing in yield compression up to 31%, but this higher value equal to 406% from is glass fiber composites. While that, result of hardness test do not show the make-up of value meaning in comparison with epoxy matrix."

"ABSTRAKSenyawa derivat piran telah berhasil disintesis dengan mereaksikan kurkumin, benzaldehida, dan asam barbiturat senyawa 3 melalui reaksi kondensasi Knoevenagel dan adisi Michael. Namun, 2 reaksi lainnya tidak berhasil membentuk senyawa derivat piran, yaitu senyawa 1 dan senyawa 2. Pada kedua reaksi tersebut digunakan reaktan dimedon, benzaldehida/sinamaldehida, dan malononitril. Ketiga produk yang terbentuk tersebut dianalisis menggunakan instrumentasi FTIR, UV-Vis, dan GC-MS atau LC-MS. Pada reaksi tersebut digunakan nanokatalis Fe3O4@kitosan yang berhasil disintesis dengan metode in situ dan dikonfirmasi dengan instrumentasi FTIR, XRD, TEM, dan PSA. Berdasarkan hasil optimasi reaksi diperoleh kondisi optimum untuk senyawa 1 adalah 1 jam reaksi, suhu ruang, dan 2,5% wt katalis dengan mol sebesar 85,24%, untuk senyawa 2 pada 45 menit reaksi, suhu ruang, dan 5% wt katalis dengan mol sebesar 48,44%, serta 8 jam reaksi, refluks, dan 5% wt untuk senyawa 3 dengan kemurnian sebesar 52,99%. Senyawa-senyawa hasil sintesis memiliki bioaktivitas sebagai antioksidan dengan nilai IC50 sebesar 57, 21, 23, 61, dan 7,47 ppm.

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ABSTRACTPyran derivatives were successfully synthesized by reacting curcumin, benzaldehyde, and barbituric acid compound 3 through Knoevenagel condensation and Michael addition reactions. Nevertheless, it was found that other 2 processes did not form pyran derivative compounds. Both of them used dimedone, benzaldehyde cinnamaldehyde, and malononitrile as reactants. Characterization of the three of products were performed by using FTIR, UV Vis, and GC MS or LC MS instrumentation. Beside that, Fe3O4 chitosan nanocatalyst also used in the reactions, which was synthesized by in situ method and characterized by FTIR, XRD, TEM, and PSA instrumentation. The optimum conditions for producing compound 1 were 1 hour at reaction, room temperature, and 2,5% wt of catalyst with mol of 85,24%, compound 2 was at 45 min of reaction, room temperature, and 5% wt of catalyst with mol of 48,44%, and 8 hours of reaction, reflux, and 5% wt for compound 3 with purity of 52,99%. Bioactivity as antioxidant was discovered in the syhthesized compounds with the IC50 values of 57, 21, 23, 61, and 7,47 ppm for the compound of 1, 2, and 3, respectively."

"Pada penelitian ini, nanokomposit clay-epoxy menggunakan Organo clay Nanomer I30E, epoxy resin DER 331 dan curing agent Versamid 125 disintesa dengan metode in situ polimerization. Sebagai pembanding, komposit serat gelas-epoxy menggunakan serat gelas komersial dan epoxy resin dan curing agent yang sama disintesa dengan metode wet laminating.Karakterisasi struktur internal dan permukaan fracture, yang masing-masing menggunakan XRD (X-Ray Diffraction) dan SEM (Scanning Electron Microscope), menunjukkan bahwa nanokomposit telah berhasil disintesa. Nanokomposit memiliki struktur eksfoliasi pada komposisi clay <7.34 (% berat) dan struktur eksfoliasi dan interkalasi pada komposisi clay ≥ 7.34 (% berat). Nanokomposit dengan komposisi clay 2.10 (% berat) terdiri dari fasa epoxy dan fasa aglomerasi clay dan memiliki tanda fracture berbentuk kerucut.Hasil uji tarik, tekan dan kekerasan menunjukkan bahwa nanokomposit, yang disintesa dengan teknik pencampuran DM (Direct Mixing), tidak layak digunakan untuk aplikasi struktural pada pesawat terbang menggantikan komposit serat gelas-epoxy. Hasil uji tarik menunjukkan nanokomposit yang terbentuk memiliki perilaku yang sama dengan komposit particulate epoxy, yaitu tensile strength yang mengalami penurunan seiring dengan penambahan komposisi clay. Hasil uji tekan dan kekerasan masing-masing menunjukkan yield compression strength yang tidak mengalami perubahan dan kekerasan mengalami sedikit peningkatan, yang tidak tergantung pada komposisi clay, seiring dengan penambahan komposisi clay.

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In this observation, clay-epoxy nanocomposites using Nanomer I30E organo clay, DER 331 epoxy resin and Versamid 125 curing agent were synthesized with an in-situ polimerization method. As comparison, fiberglass-epoxy composites using commercial fiber glass and the same epoxy resin and curing agent were synthesized with wet laminating method.

Characterization of internal structure and fracture morphology, using XRD (X-Ray Diffraction) and SEM (Scanning Electron Microscope) respectively, showed that nanocomposites had been successfully synthesized. Nanocomposites owned an exfoliated structure at clay composition <7.34 (% weight) and a mixture of exfoliated and intercalated structure at clay composition >7.34 (% weight). The nanocomposite with clay composition 2.10 (% weight) consisted of epoxy fase and clay agglomerates fase and owned cone shape fracture markings.

The results of tensile, compression and hardness testings showed that nanocomposites, synthesized using DM (Direct Mixing) dispersion technique, was found not suitable for structural application in aircraft replacing fiberglass-epoxy composite. The result of tensile testing showed nanocomposite formed owned similar behavior to particulateepoxy composite, where the tensile strength experienced decrease as clay composition was increased. The results of compression and hardness testings showed that yield compression strength didn’t experience change and hardness experienced few increases, which was not affected by clay’s composition, as clay's composition increased."