Judul: Adsorpsi ion Cr(III) dan Cr(VI) menggunakan bentonit alam termodifikasi oksida besi
Abstrak: Speciation of trivalent and hexavalent chromiums is important to do because both have very different characteristics. Hexavalent chromium is toxic meanwhile trivalent chromium is needed in metabolism. The aim of this study is to modify natural bentonite from Cigudeg, Bogor with sodium and iron oxide to increase its performance as an adsorbent for speciation of Cr (VI) and Cr (III). The result showed that the adsorption capacity of Cr(III) and Cr(VI) using Na-bentonite and modified bentonite were higher than that of natural bentonite. Adsorption capacity of Cr(III) for natural bentonite, Na-bentonite, and modified bentonite were 4.49, 6.08, and 8.17 mg/g adsorbent, meanwhile adsorption capacity of Cr(VI) for natural bentonite, Na-bentonite, and modified bentonite were 4.14, 4.97, and 5.85 mg/g adsorbent, respectively. Adsorption of Cr(III) and Cr(VI) by the three types of bentonite followed the Langmuir isotherm pattern. Characterization using X-ray diffractometer showed shifting, broadening, and changing in the number of peaks in the diffractogram of Na-bentonite and modified bentonite compared to that of natural bentonite. Speciation using adsorption column is constrained by the low flow rate.
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Judul: Adsorpsi dan desorpsi ion kromium(VI) pada bentonit yang dimodifikasi Heksadesiltrimetilamonium bromida
Abstrak: Bentonite is abundant mineral in Indonesia and potentially as adsorbent. Bentonite has negatively charge, so bentonite has high capability to adsorp cations, while the capability of bentonite to adsorp anion was very low. This research was modified bentonite from Leuwiliang with hexadecyltrimethylammonium bromide (HDTMABr). The result of bentonite modification was changes bentonite surface character from hidrofilic become hidrofobic or organofilic, so that can adsorp anion, like Cr(VI). This research made organobentonite 25, 50, and 100 % CEC. Some methodes were done in this research, they were determination of CEC, acidity, and adsorption optimum condition of Cr(VI) that covered determination of adsorption pH, contact time, isotherm, and desorption of Cr(VI) from organobentonite. Capacity Exchange Cation of bentonite, organobentonite 25 %, organobentonite 50 %, and organobentonite 100 % were 54.53, 45.14, 37.37, and 20.72 me/100 g, respectively. Acidity of bentonite, organobentonite 25 %, organobentonite 50 %, and organobentonite 100 % were 4.95, 3.62, 0.90, and 0.60 mmol/g, respectively. Optimum adsorption condition of Cr(VI) onto bentonite, organobentonite 25 %, organobentonite 50 %, and organobentonite 100 % were consist of pH 2 until 4, contact time 3 until 4 hours, on concentration 200 until 500 ppm. Adsorbtion capacity of bentonite, organobentonite 25 %, organobentonite 50 %, and organobentonite 100 %, respectively were 4.44, 11.96, 22.09, and 20.53 mg/g. Ability of HCl, aquadest, and CaCl2 to desorbed Cr(VI) from organobentonite was low, this matter showed that Cr(VI) was trapped strongly on organobentonite.
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Judul: Anatomi otot-otot ekspresi wajah monyet ekor panjang (Macaca fascicularis)
Abstrak: Hewan primata banyak digunakan untuk penelitian biomedis karena memiliki kemiripan anatomi dengan manusia. Evolusi dari otot wajah mamalia yang berhubungan dengan ekspresi wajah dan komunikasi visual terutama pada hewan pimata dalam hal ini otot-otot daerah kelopak mata serta mulut memegang peranan penting (Bennet et al., 1995). Monyet ekor panjang (Macaca fascicularis) adalah slah satu jenis hewan primata di antara 5 hewan primata yang paling banyak digunakan untuk penelitian biomedis (Anonimus, 2000; Anonimus, 2002). Penelitian ini bertujuan untuk mempelajari morfologi otot-otot ekspresi wajah beserta origo dan insersionya untuk melengkapi data dasar anatomi otot pada M. fascicularis. Penelitian ini menggunakan tiga ekor preparat monyet ekor panjang yang telah diawetkan dalam larutan formalin 10% dan sebuah tengkorak kepala beserta tulang rahang bawah monyet ekor panjang. Pengamatan yang dilakukan meliputi morfologi otot beserta origo dan insersionya, dan hubungannya dengan variasi ekspresi wajah yang mampu dilakukan monyet ekor panjang, kemudian membandingkannya dengan literatur anatomi manusia, beberapa hewan primata lain, hewan herbivora dan karnivora. Dari hasil pengamatan, pada susunan otot ekspresi wajah monyet ekor panjang ditemukan lima kelompok otot: 1). Kelompok otot kulit kepala yaitu: m. occipitofrontalis (gabungan m. frontalis dan m. occipitalis). 2). Kelompok otot hidung yaitu: m. nasolabialis. 3). Kelompok otot mulut yaitu: m. nasolabialis, m. zygomaticus major, m. zygomaticus minor, m. levator anguli oris, m. depressor anguli oris, m depressor labii inferioris, m. mentalis, m. buccinatorius, m. orbicularis oris dan m. platysma. 4). Kelompok otot telinga yaitu: m auricularis posterior, m. auricularis superior dan m. auricularis anterior. 5). Kelompok otot kelopak mata yaitu: m. orbicularis oculi, m. corrugator supercilii dan mlevator palpebrae superioris. Setiap kelompok otot memiliki berbagai karakteristik baik morfologi maupun origo dan insersio yang berbeda dengan primata. lain, kuda, sapi dan anjing. Hal tersebut menghasilkan variasi fungsi otot yang berbeda sesuai dengan perilaku dan pola hidup.
Keyword: Macaca fascicularis, long-tailed macaque, monkey