Judul: Potential of Watermelon Peel as an Adsorbent in the Adsorption of Methyl Orange
Abstrak: Limbah pertanian berupa kulit semangka merupakan salah satu sumber adsorben yang dapat digunakan pada adsorpsi zat warna. Limbah zat warna akan memberikan dampak negatif terhadap lingkungan, termasuk organisme di dalamnya. Dari berbagai zat warna yang digunakan dalam industri tekstil dan kimia, metil jingga menjadi salah satu pewarna azo anionik yang paling sering digunakan. Penelitian ini bertujuan menentukan kapasitas dan efisiensi adsorpsi metil jingga terbaik dan mempelajari kajian isoterm adsorpsi dari dari kulit semangka. Metode adsorpsi batch digunakan untuk mengamati proses adsorpsi metil jingga. Kadar air kulit semangka adalah 95,30%. Hasil spektrum FTIR menunjukkan adanya gugus fungsi O-H, C-H, C-C, C-O-C, dan N-H. Waktu adsorpsi terbaik diperoleh dengan kapasitas dan efisiensi adsorpsi berturut-turut 7,66 mg/g dan 76,65%, yang dihasilkan pada kondisi 15 menit, bobot adsorben 0,02 gram, dan konsentrasi metil jingga 5 ppm. Model isoterm adsorpsi metil jingga mengikuti isoterm Langmuir dengan nilai R2=0,5513. Hasil penelitian menunjukkan kulit semangka berpotensi sebagai adsorben alternatif untuk zat warna., Agricultural waste in the form of watermelon rinds is one source of adsorbent that can be used for dye adsorption. Dye waste will have a negative impact on the environment, including the organisms in it. Of the various dyes used in the textile and chemical industries, methyl orange is one of the most frequently used anionic azo dyes. This research aims to determine the best adsorption capacity and efficiency of methyl orange and study the adsorption isotherm of watermelon rind. Adsorption method batch used to observe the methyl orange adsorption process. The water content of watermelon rind is 95.30%. The FTIR spectrum results show the presence of O-H, C-H, C-C, C-O-C, and N-H functional groups. The best adsorption time was obtained with adsorption capacity and efficiency of 7.66 mg/g and 76.65% respectively, which was produced under conditions of 15 minutes, adsorbent weight of 0.02 grams, and methyl orange concentration of 5 ppm. The methyl orange adsorption isotherm model follows the Langmuir isotherm with an R value2=0.5513. The research results show that watermelon peel has the potential as an alternative adsorbent for dyes
Keyword: Adsorpsi, Kulit Semangka, Metil Jingga, Model Isoterm

Judul: Adsorpsi Asam Lemak Bebas dan Zat Warna Biru Metilena Menggunakan Campuran Selulosa Kayu Sengon-Zeolit
Abstrak: Limbah minyak goreng bekas dan zat warna dari berbagai macam industri merupakan penyebab pencemaran di Indonesia. Tujuan penelitian ini adalah melakukan adsorpsi asam lemak bebas dari minyak goreng bekas dan zat warna biru metilena menggunakan selulosa hasil isolasi kayu sengon dan zeolit yang diaktivasi secara asam, menentukan kondisi optimum adsorpsi, serta menentukan isoterm adsorpsi dan kinetika adsorpsi. Percobaan yang digunakan adalah metode tumpak. Kondisi yang dioptimisasi meliputi bobot, waktu, dan nisbah dari kedua adsorben. Kondisi optimum adsorpsi asam lemak bebas didapatkan pada bobot 1 gram, dengan nisbah adsorben 3:1 pada selulosa:zeolit, dan waktu adsorpsi selama 60 menit. Kondisi optimum zat warna biru metilena didapatkan pada nisbah adsorben 1:3 untuk selulosa:zeolit pada waktu 10 menit. Adsorpsi asam lemak bebas dan biru metilena mengikuti isoterm Freundlich. Adsorpsi asam lemak bebas dan biru metilena mengikuti kinetika reaksi orde dua semu.
Keyword: adsorption, adsorption kinetics, cellulose, free fatty acid, methylene blue, zeolite

Judul: Posisi Filogenetik Kura-Kura Carettochelys Insculpta  (Reptillia: Testudinata)
Abstrak: Carettochelys insculpta is an endemic freshwater turtle of southern Papua and northern Australia. Phylogenetic position of this turtle is remain unresolved until now. Most of the research conducted show close relationships of C. insculpta and members of Trionychidae family. However, some of the research show distance between C. insculpta and members of Trionychidae family. This research is conducted to analyze phylogenetic relationship between C. insculpta and other members of Testudinata using 12S rRNA, 16S rRNA, and both gene as markers. DNA samples were obtained from three different organisms of C. insculpta. Two species used as outgroups were Alligator mississippiensis and Iguana iguana. Phylogenetic analysis was carried out using Neighbor-Joining method with Felsenstein 1981 (F81) modeltest. A polytomy tree of Testudinata was produced by using 12S rRNA gene. However, analysis using 16S rRNA and both genes as markers confirmed that C. insculpta was located between the Chelonidae and the Trionychidae family.
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