Judul: Reduksi Logam Berat Hg, Ag, Dan Cr Limbah Laboratorium Menggunakan Metode Presipitasi Dan Adsorpsi
Abstrak: Laboratory operational activities produce solid, liquid, and gasions wastes. Increased laboratory activities such as research and other laboratory ser vices result in increasing of the wastes quantity. Some types of wastes contain heavy metals such as Hg, Ag, and Cr. This heavy metals are toxic and pollute the environment. Appropriate treatment can reduce the heavy metals concentration in liquid waste. The objectives of this research were to determine the optimum condition of precipitation and adsorption, to determine the removal efficiency and the quality of the treated liquid. The studied liquid wastes is cha racterized by very highly acidi zand highly content of heavy metals. The characteristics are pH values of 1.3 – 1.4, COD of 320 – 360 mg/L, Hg of 77.6 – 391.6 mg/L, Ag of 2.6 – 9.14 mg/L, and Cr of 11.36 – 21.9 mg/L. Additition of NaOH 50% resulted in reduction of 97% for Hg at pH 11.63, 98.95% for Ag at pH 11.63 and 96.85% for Cr at pH 9 .77. Based on the results, Hg did not meet the requairement, the others me tal Ag and Cr concentrations met the requirement. Adsorption using activated carbon in the forms of granule and powder reduced COD and heavy metals (Hg, Ag, Cr) significanly. The qu ality of treated liquid waste was high and met the requirement according to Kepmen N0. 51/1995.
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Judul: Pengolahan Limbah Cair Laboratorium Bekas Pengujian Kebutuhan Oksigen Kimiawi (KOK) dengan Metode Presipitasi
Abstrak: Determination of chemical oxygen demand (COD) parameter in water samples produce laboratory waste which are still harmful to be dumped to the environment. It is because COD testing still use several reagents containing heavy metals such as Ag, Cr, and Hg. This research was focused on Hg removal, because of its higher toxicity compared with the two others. The initial COD waste contained 5241.4 mg/L of Hg, whereas the quality standard of Hg according to PP No. 82/2001 is 0.002 mg/L. Precipitation method was studied in this research to treat this COD waste, especially to reduce the Hg content. The precipitation was carried out with hydroxide and carbonate. From several methods tested, 5 of which decreased significant amount of Hg, which were hydroxide precipitation with acid addition (HA), multilevel hydroxide precipitation (HB), carbonate precipitation with addition of hydroxide and acid (KHA), multilevel hydroxide precipitation with acid addition (HBA), and multilevel hydroxide precipitation with addition of salt and acid (HBGA). Those five methods could decrease the Hg content up to 99.96%, into 2.1939, 2.7513, 2.0185, 2.5858, and 2.1683 mg/L, respectively. However these results had not yet fulfilled the quality standard
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Judul: Karakteristik Anatomi Skelet Kepala Buaya senyulong (Tomistoma schlegelii).
Abstrak: Buaya sepit atau senyulong (Tomistoma schlegelii) merupakan jenis buaya asli Indonesia yang berhabitat di sungai-sungai Sumatera, Kalimantan, dan juga pedalaman Sulawesi. Salah satu ciri khas buaya senyulong adalah bentuk moncong yang runcing dan sempit, namun hingga saat ini informasi mengenai struktur skelet kepala buaya senyulong sangat terbatas. Penelitian ini bertujuan untuk mempelajari karakteristik anatomi skelet kepala buaya senyulong yang dikatikan dengan fungsi dan perilakunya. Penelitian dilakukan secara eksploratif dengan melakukan pengamatan, pencatatan, dan pengambilan gambar dari skelet kepala buaya senyulong. Skelet kepala berukuran panjang 70 cm, lebar 29 cm, dan tingggi 17 cm dengan permukaan kasar pada os nasale, os frontale, os maxilla, os mandibula, os lacrimale, os jugale. Jumlah gigi pada buaya ini sebanyak 78 buah, terdiri dari 4 buah gigi premaxila, 16 buah gigi maxila, dan 19 buah gigi mandibula. Pada regio orbitalis ditemukan dua pasang fenestrae temporales yang berkembang baik. Fenestra supratemporale merupakan lubang oval yang membentang di sepanjang os parietale. Fenestra infratemporale berbentuk segitiga dan dibatasi oleh os squamosum, os postorbitale, os jugulare, dan os quadratum. Os mandibula hewan ini mempunyai symphysis mandibularis yang panjang yaitu garis yang melintang di corpus mandibulae. Secara fungsional ukuran symphysis mandibularis berkaitan dengan adaptasi hewan terhadap diet makan.
Keyword: kepala, moncong, Tomistoma schlegelii