Judul: Peran Surfaktan Setiltrimetilamonium Bromida dan Natrium Dodesil Sulfat pada Sintesis ZnO dengan Metode Hidrotermal
Abstrak: Zno crystal is the main preference material in various applications recently, such as in semiconductors, ultraviolet lasers, and catalysts. This study aims to synthesize ZnO with addition of surfactant. ZnO crystals were synthesized by reacting ZnSO4, KOH, and surfactants using hydrothermal method. The first step was to determine the best ratio of ZnSO4: KOH (1:2; 1:3; 1:4, and 1:5) based on X-ray diffraction. The second step was to evaluate the role of surfactan cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS) on the synthesis of ZnO crystals. The result of this study showed the best ratio of ZnSO4:KOH was 1:3, based on the least of impurities and the highest degree of crystallinity (85.64%). The addition of surfactant CTAB and SDS in the synthesis of ZnO increased the degree of crystallinity, which were 98.28% and 92.17%, respectively. Based on mathematical calculation using Scherrer equation, the crystal size without surfactant was 32 nm, whereas with CTAB and SDS the crystallited size were 28 nm and 29 nm, respectively. The degree of crystallinity and crystal size indicated that CTAB surfactant produce ZnO crystals with the best characteristics as compared to SDS surfactant or without surfactant.
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Judul: Sintesis ZnO dengan Tambahan Surfaktan Kationik dan Anionik Menggunakan Metode Hidrotermal
Abstrak: ZnO is a semiconductor material that has been widely used in various applications, such as solar cell. This study aimed to synthesis ZnO with ZnSO4 and KOH using hydrothermal method and evaluate the effect of surfactants on the synthesis process. First, ZnO was synthesized with various concentrations of ZnSO4:KOH (1:2, 1:3, 1:4 and 1:5). The best result was chosen by X-ray diffraction analysis. Synthesis of ZnO with the best ratio was carried out again with the addition of cationic surfactant, cetyltrimethylammonium bromide (CTAB), and anionic surfactant, sodium dodecyl sulphate (SDS). Based on the diffractograms, the best ratio was 1:2 with 86.29% crystallinity. This ratio was chosen due to the high crystallinity and the least impurities. Synthesis with the addition of CTAB and SDS gave higher crystallinity, 88.76% and 89.13%, respectively. Based on calculation using Scherrer’s equation, it showed that the addition of CTAB resulted the smallest crystal size. Based on those data, it can be concluded that surfactants have improved the characteristics ZnO by increasing the crystalinity and reducing the crystal size.
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Judul: Characteristics and Nest Distribution of Red-breasted Parakeet (Psittacula alexandri) and Long-tailed Parakeet (Belocercus longicaudus) at the IPB Darmaga Campus
Abstrak: Betet biasa dan betet ekor-panjang merupakan dua spesies burung paruh bengkok yang terancam punah. Penelitian ini bertujuan untuk mengidentifikasi karakteristik tempat bersarang dan memetakan persebaran pohon sarang kedua jenis betet yang berada di Kampus IPB Darmaga. Tempat bersarang betet dicari dengan menggunakan metode eksplorasi dan metode wawancara, sedangkan pola persebaran pohon sarang betet dianalisis dengan menggunakan metode Nearest Neighbour Statistic (R). Hasil penelitian menunjukkan bahwa kedua jenis betet yang berada di Kampus IPB Darmaga bersarang pada lima jenis pohon. Kedua jenis betet cenderung lebih memilih bersarang pada pohon yang memiliki tajuk dominan dengan bentuk tajuk rounded dan bentuk percabangan vertical atau tortuous. Pohon yang digunakan sebagai tempat bersarang oleh kedua jenis betet merupakan pohon tidak sehat dengan berat jenis kayu yang rendah. Lubang sarang betet ditemukan pada cabang pohon yang memiliki dimensi tinggi dan besar. Pola persebaran pohon sarang kedua jenis betet cenderung berkelompok.
Keyword: Belocercus longicaudus, nest-characteristics, Psittacula alexandri