Judul: Pengaruh Nisbah Reaktan Lignin-NaHSO3 dan pH pada Produk Natrium Lignosulfonat
Abstrak: Lignin diisolasi dari lindi hitam dengan pereaksi H2SO4 20%. Sulfonasi terhadap lignin menghasilkan NaLS yang dapat dimanfaatkan sebagai zat pendispersi, pengikat, penukar ion, dan aditif pada beton. Pada penelitian ini dilakukan sulfonasi terhadap lignin dengan nisbah reaktan lignin-NaHSO3 1:0.4, 1:0.5, dan 1:0.6 dan pH awal 5, 6, atau 7. Parameter yang diamati ialah kemurnian, pH akhir, dan Rendemen NaLS. Kenaikan pH awal meningkatkan pH akhir dan rendemen NaLS, tetapi menurunkan kemurniannya. Kenaikan nisbah lignin-NaHSO3 meningkatkan rendemen dan menurunkan kemurnian, tetapi tidak berpengaruh pada pH akhir NaLS. Kondisi optimum yang dipilih pada pH awal 6 dan nisbah lignin-NaHSO3 1:0.6. Pencirian gugus fungsi menggunakan spektrofotometri inframerah menunjukkan telah terjadi reaksi sulfonasi terhadap lignin. Hal ini dapat dilihat dengan terbentuknya serapan baru pada bilangan gelombang 626 nm yang menunjukkan ikatan C–S.
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Judul: Utilization of kraft lignin from black liquor pulp factory to produce sodium lignosulfonate and sulfonate hydroxymethyl phenol sulfuric acid lignin as dispersant material
Abstrak: Black liquor kraft is a sulfuric chemical pulping byproduct. Lignin is the highest component in a black liquor approximatelly 46% from the total solid. Lignin can be isolated from kraft process black liquor by precipitation using H2SO4 20% to pH 2. The purposes of this research were to obtain and characterize kraft lignin, to find an optimum condition for sulfonation process in order to get a sodium lignosulfonate (SLS) product with appropriate characteristics as a dispersant material, to get sulfonate hydroxymethyl phenol sulfuric acid lignin (SHP-SAL), and to understand the performance of SLS and SHPSAL as dispersant agents on gypsum paste. The raw materials used in the production of SLS and SHP-SAL were obtained from sulfonated lignin which was isolated from black liquor. The SLS were made from lignin which was obtained from the sulfonation of isolated lignin in the presence of NaHSO3, also from the optimized sulfonation process of lignin using Response Surface Method (RSM) and Central Composite Design (CCD) with three factors. The SHP-SAL were made in three steps: (1) sulfuric acid lignin (SAL) was phenolated to produce phenol sulfuric acid lihnin (PSAL), (2) the hydroxymethylation of P-SAL to give hydroxymethyl phenol sulfuric acid lignin (HP-SAL), and (3) the sulfonation of HP-SAL to yield sulfonate hydroxymethyl phenol sulfuric acid lignin (SHP-SAL). The lignosulfonate compounds were identified using infrared spectrophotometer.
Keyword: Response Surface Method (RSM), Central Composite Design (CCD), Dispersibilitas

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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