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: 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: Sistem Navigasi pada Robot Pemadam Api Menggunakan Wall Following dan Logika Fuzzy
Abstrak: A robot needs a good navigation to complete its task. One way to provide navigation capabilities on robots is artificial intelligence. Navigation capabilities using artificial intelligence may be associated with the ability to accept input from a range of sensors. However, inputs from the environment are uncertain so that a simple modeling is not sufficiently representative. Fuzzy logic is expected to overcome these uncertainties. This research aims to develop the navigation system on a fire-fighter robot using wall following algorithms and fuzzy logic. The system is simulated on KRPAI 2013 environment where the robot is expected to move by following the wall, extinguishing the fire, and returning to home. It is shown that the robot has successfully completed the mission on KRPAI 2013 with a success rate of 87.5%.
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