Judul: Kajian Isoterm, Kinetika, dan Termodinamika Adsorpsi Strontium Menggunakan TiO2-Zeolit Lampung
Abstrak: Limbah bahan bakar nuklir setelah mengalami radiasi mengandung sejumlah isotop strontium yang dapat dimanfaatkan kembali, tetapi limbah tersebut masih tercampur dengan unsur atau isotop lainnya sehingga diperlukan proses pemisahan. Salah satu metode pemisahan strontium adalah dengan adsorpsi. Dalam penelitian ini, campuran TiO2-zeolit lampung dievaluasi kinerjanya sebagai adsorben untuk adsorpsi strontium. Parameter yang diamati meliputi model isoterm, kinetika, dan termodinamika adsorpsi. TiO2-zeolit yang dicirikan menggunakan spektroskopi fourier transform infrared menunjukkan puncak serapan Ti-O-Si pada zeolit lampung setelah ditambahkan TiO2. Analisis difraksi sinar X memperlihatkan zeolit lampung berjenis klinoptilolit dan mordenit, serta TiO2 yang digunakan memiliki fase anatase. Analisis mikroskop elektron payar mengindikasikan TiO2 tersebar pada permukaan zeolit lampung. Model isoterm adsorpsi untuk adsorben TiO2-zeolit adalah model isoterm Langmuir. Adsorpsi strontium mengikuti orde kedua semu dan kajian termodinamika menunjukkan proses adsorpsi bersifat endoterm dan tidak spontan., Nuclear fuel waste after undergoing radiation contains a number of strontium isotopes that can be reused, but these wastes are still mixed with other elements or isotopes so a separation process is needed. One of the methods of separation of strontium is by adsorption. In this study, the float TiO2-zeolite mixture was evaluated for its performance as an adsorbent for strontium adsorption. The observed parameters include isotherm models, kinetics, and adsorption thermodynamics. TiO2-zeolite characterized using infrared fourier transform spectroscopy showed a peak of Ti-O-Si uptake in lampung zeolite after adding TiO2. X-ray diffraction analysis displayed that it was of the type of clinoptilolite and mordenite, and the TiO2 used had an anatase phase. Analysis of electron microscopy indicated that TiO2 was dispersed on the surface of lampung zeolite. The adsorption isotherm model for TiO2-zeolite adsorbents is the Langmuir isotherm model. Strontonium adsorption followed a quasi-second order and thermodynamic studies showed that the adsorption process was endothermic and not spontaneous.
Keyword: Adsorption, strontium, TiO2, Zeolite

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: Kemampuan hidup Dysmicoccus brevipes (cockerell) dan D. neobrevipes beardsley (hemiptera: pseudococcidae) pada berbagai benih kacang
Abstrak: Kutu putih Dysmicoccus brevipes (Cock) dan D. neobrevipes Beard (Hemiptera: Pseudococcidae) adalah serangga yang sangat luas penyebarannya dan memiliki inang dari berbagai jenis komoditas serta merupakan vektor penyakit layu nenas yang disebabkan oleh PMWaV.
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