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 dan desorpsi kromium (VI) pada zeolit alam asal Lampung termodifikasi Heksadesiltrimetilamonium bromida
Abstrak: Zeolite is a mineral that is able to adsorp chromium. Chromium has three stable forms in nature,i.e. metal chromium, trivalent chromium, and hexavalent chromium. Among these forms, hexavalent chromium are the most toxic and generally obtained in its anion form as chromat (CrO4 2-) and dichromat (Cr2O7 2-). Therefore, it is very important to decrease content in environment. The function of negative zeolite structure were cation exchange and their somewhat for anion exchange. Therefore, modified zeolite with hexadeciltrimethylammonium bromide (HDTMABr) was attempted to increase anion adsorption capacity of zeolite in solution. Modified zeolite with HDTMABr at 50% dosage of its cation exchange capacity, caused an increase the adsorption capacity of zeolite to chromium(VI) from 0.74 to 1.40 mg/g. Adsorption was carried out by varying adsorption time, solution acidity, and initial concentration of chromium(VI). The optimum adsorption time, solution acidity, and initial concentration of chromium(VI) for unmodified-zeolite were 20 hours, 3.5, and 350 ppm, respectively. On the other hand, the optimum adsorption for modified-zeolite were 23 hours, 5, and 350 ppm, respectively. Isotherm type for both of adsorbent followed Freundlich isotherm. Desorption of chromium(VI) on unmodifiedzeolite and modified-zeolite a lot off obtained using aquadest at level 30.56 and 0.33%, respectively.
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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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