AbstrakPertukaran ion antara Cr 3+ dan H + menggunakan zeolit sebagai penukar ion adalah salah satu metode untuk memurnikan air dari ion kromium. Zeolit adalah senyawa aluminosilikat tetrahedral dengan struktur ikatan 3-dimesi, memiliki pori bagian dalam, dan luas permukaan yang tinggi, karena itu dapat digunakan sebagai adsorben. Tujuan penelitian ini adalah untuk mengevaluasi pengaruh waktu kontak optimum, suhu, dan konsentrasi kromium terhadap kapasitas penyerapan. Tahap pertama adalah mencampur zeolit yang telah diaktifkan dengan larutan kromium (10 ppm kromium) dalam tangki berpengaduk pada 25 and H + by using zeolite as its ion exchanger is one of methods to purify water from cromium ion content. Zeolite is aluminosilicate tetrahedral compound that has 3-dimensional framework structures with pore inside and high surface area, therefore it can be used as adsorbent. The objective of this research is to evaluate the effect of optimum contact time temperature and cromium concentration toward adsorption capacity. The first step is mixing activated zeolite and cromium solution (10 ppm) in a stirred tank at 25 o C. Then solution was taken for every 60 minutes until concentration of cromium residue solution was constant. For temperature effect test, cromium solution used were 10 ppm with temperature variation of 25, 30, 35, 40, 45, and 50 o C. For isotermal adsorption test, the best temperature was used from step before with concentration variation of 10, 20, 40, 60, and 100 ppm. Dosage of adsorbent used is 3 gram adsorbent/200 mL cromium solution with stirring speed 240 rpm. Cromium ion is detected by using AAS (Atomic Adsorption Spectroscopy). The results showed that optimum contact time is 3 hours by using acid activated zeolite with optimum adsorption 99.275%. Isoterm model followed Freundlich isoterm with equation Qe = 0.044463C 1/2.5125 that adsorption capacity Kf = 0.044463 mmol/gram adsorbent and adsorption intensity n = 2.5125.

A B S T R A C TThe mixture of adsorbents of moringa seed (BK) and natural zeolite of Lampung (ZAL) is placed in a fixed bed adsorber column arranged at a certain height according to the designed height ratio. BK is processed by extraction to remove its oil content while ZAL is activated by chemical and physical treatments. Composition ratio of BK-ZAL (cm/cm) was varied i.e.1:1, 1:2 and 1:3 and concentrations of Pb entering adsorber were 1 ppm and 2 ppm. The adsorption conditions were 20-35 mesh of adsorbent size, 4 cm column diameter of adsorber, 5 cm bed height, and 8 liters/3 hours flowrate. Upflow adsorption was performed in the fixed bed adsorption column for 3 hours and Pb solution of the adsorber output was taken at every 30 minutes. Analysis of Pb content was performed by Atomic Absorption Spectroscopy (AAS). The BK Adsorbent before and after extracted, and after adsorption were characterized using Fourier Transmission Infra Red (FTIR). ZAL before and after activation were characterized using X-Ray Diffraction (XRD), X-Ray Fluorescence (XRF), and Fourier Transmission Infra Red (FTIR). The characterization results of XRD, XRF and FTIR showed that the crystalline phases of ZAL increased, the activation process of ZAL only caused a shift in the peak, no significant change in the structure of solids, and the content of impurities in ZAL reduced after activation, thereby enhancing its ability to adsorb Pb. AAS analysis results showed that the best combination adsorbent BK-ZAL (cm/cm) was 1: 2 with the highest effectiveness of the entrapment of Pb metal reached 99.90%. The adsorption capacity of adsorbent was 2.25 mg Pb/ gram adsorbent as calculated using Freundlich equilibrium model.

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AbstrakTelah dilakukan penelitian penggunaan material aluminasilikat MCM-41 sebagai adsorben limbah cair tapioka. Dalam penelitian ini dipelajari permodelan isotermal dan kinetika adsorpsi dari material MCM-41 pada proses adsorpsi limbah cair tapioka. Isotermal Langmuir dan Freundlich digunakan sebagai permodelan isotermal data penelitian. Dari data penelitian yang diperoleh pada konsentrasi COD sebesar 416 -784 mg/L, proses adsorpsi limbah cair tapioka oleh MCM-41 sesuai dengan pendekatan isothermal Langmuir. Kapasitas maksimum adsorpsi MCM-41 diperoleh dari pendekatan Langmuir adalah sebesar 15,92 mg/g. Model kinetika pseudo-orde pertama dan pseudo-orde kedua digunakan untuk analisis kinetika adsorpsi pada data penelitian. Model kinetik pseudo-orde pertama yang sesuai dengan proses adsorpsi limbah cair tapioka dengan laju penyerapan adalah 7,48 x 10 -2 dan 7,37 x 10 -2 g/(min-mg) untuk konsentrasi awal secara berturut-turut adalah 608 dan 784 mg/L. Kata kunci: adsorpsi, kinetika adsorpsi, limbah cair, MCM-41, tapioka AbstractAluminasilicate MCM -41 material was studied as an adsorbent for tapioca wastewater. The adsorption isotherm modeling and adsorption kinetics of MCM -41 to the liquid waste of tapioca was investigated. Langmuir and Freundlich isotherms were applied to describe the experimental data. Equilibrium data fitted well to the Langmuir model for COD concentration range of 416 -784 mg/L. The maximum adsorption capacity of the MCM-41 obtained from the Langmuir model was 15.92 mg/g. The pseudo-first-order and pseudo-second-order kinetic models were employed to describe the kinetic data. The experimental data fitted well to the pseudo-first-order kinetic model with constant rates 7.48 x 10 -2 and 7.37 x 10 -2 g/(min-mg) for initial concentrations 608 and 784 mg/L, repectively.

Research in utilization of Lampung natural zeolite/coal-fly ash was performed to observe its effect on fuel consumption savings and the reduction of exhaust emissions on a 4-stroke petrol motorcycle. Percentage variations of zeolite/coal-fly ash were abbreviated by 0/100 (Z0-F100), 25/75 (Z25-F75), 50/50 (Z50-F50), 75/25 (Z75-F25), and 100/0 (Z100-F0) (wt.%). Tests of fuel consumption were conducted by stationary tests at engine speed of 1000, 3000, and 5000 rpm and road tests as far as 5 km. Meanwhile, exhaust emissions tests were performed at engine speed of 1500 and 3500 rpm. Filter of zeolite/coal-fly ash was put on the air filter casing, so before entering the combustion chamber, the combustion air was firstly contacted with this filter. The test results showed that the best fuel consumption savings for stationary tests occurred in the use of filter Z25-F75 that is as big as 53.06%, and the best fuel consumption savings in road tests as far as 5 km at a constant speed of 60 kph also occurred in the use of filter of Z25-F75 that is by 33.43%. In addition, the highest reduction of CO and HC concentration also occurred in the use of filter of Z25-F75 that is by 38.47% and 30%, respectively.

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Zeolite Lynde Type A (LTA) has been widely applied, such as adsorbent, catalyst, membrane, ion exchanger, and even molecular sieve. As molecular sieve, the zeolite LTA has high dehydration ability and has a prospect as separation agent such as water removal from the ethanol-water mixture to obtain high purity bioethanol. Furthermore, it can repeatedly be used, lower energy usage, and environmentally friendly. Due to the number of advantages possessed, this research conducted to synthesize the zeolite LTA. The sources of silica and alumina used are from Coal Bottom Ash (CBA), PLTU Tarahan, Indonesia. CBA is a waste of coal burning that has not fully utilized. This effect of aging time was examined to obtain the highest percentage of its crystallinity. The results showed that 36 hours aging gave a product of zeolite with the best characteristics. The XRD analysis reported that this zeolite had 89.43% of crystallinity. The FTIR identification showed the presence of double rings structure which is characteristic of zeolite LTA. Finally, the result of SEM expressed the morphology of zeolite A on 3.163 μm of crystal size.

The most effective way to reduce the pollution of heavy metal waste is the adsorption process using an adsorbent. Sugarcane bagasse is one of materials that has high affinity to absorb heavy metals. The adsorption capacity of sugarcane bagasse can be increased by converting it into cellulose xanthate by reaction of cellulose with carbon disulfide (CS2). Synthesis of cellulose xanthate consists of three stages, i.e isolation, alkalization, and xanthation. In this study, the preparation of cellulose xhantate was conducted by adding carbon disulfide (CS2) about 180% (w/w). The temperature of xhantation reaction was varied  at 35°C, 40°C and 45°C. The effect of temperature reaction into degree of substitution (DS), the degree of polymerization (DP) and the metal adsorption capacity of cellulose xanthate for Zn2+ and Pb2+ were determined by quantitative and qualitative analyze. Morphological characteristics of cellulose xanthate was characterized by SEM and the functional groups contained in the cellulose xanthate was characterized by FTIR. The result showed that cellulose xanthate synthesized at temperature of 35°C have a highest value of DS, DP, and the adsorption capacity higher than two variations of  temperature (40°C and 45°C). The value of DS, DP, and the adsorption capacity is 0.389,  299.27, 48.353 mg/g for Zn2+ metal and 51.763 mg/g for the metals Pb2+, respectively