Judul: Karbon Aktif dari Tempurung Inti Sawit sebagai Adsorben Zat Warna.
Abstrak: Proses adsorpsi menggunakan karbon aktif merupakan cara yang mudah, efektif, dan efisien untuk mengolah limbah zat warna. Limbah pertanian berupa tempurung inti sawit dapat digunakan sebagai bahan dasar dalam pembuatan karbon aktif. Metode yang digunakan untuk menyiapkan karbon aktif berupa aktivasi secara kimia. Bahan dasar berupa limbah tempurung dicampur dengan H3PO4 dengan nisbah (b/v) 1:1, serta dicampur dengan pelambat nyala dengan nisbah 1:8, 1:16, dan 1:24. Pelambat nyala dan H3PO4 dapat menghambat proses pembakaran dan meningkatkan rendemen produk. Rendemen tertinggi ialah produk dengan tambahan pelambat nyala dengan nisbah 1:24, sedangkan kapasitas adsorpsi tertinggi ialah dengan tambahan H3PO4. Isoterm adsorpsi dari karbon aktif yang dihasilkan mengikuti isoterm Langmuir.
Keyword: adsorpsi, H3PO4, isoterm, karbon aktif, pelambat nyala

Judul: Pemanfaatan Karbon Aktif dengan Aktivator H3PO4 dari Limbah Padat Agar sebagai Penjerap pada Limbah Cair Industri Penyamakan Kulit
Abstrak: Agar solid waste can be used as an adsorbent in the form of activated carbon. The study aims were to determine the best concentration of H3PO4 and activation time on the processing of activated carbon and the effectiveness of activated carbon as an adsorbent in the tanning industry wastewater. The activation step of activated carbon was carried out with H3PO4 concentration of 10; 20; 30% and the time activation of 15; 20; 25 hours. The best activation treatment was obtained on 10% H3PO4 concentration and 15 hours activation time with activated carbons yield of 93.42%, moisture content of 10.59%, ash content of 65.91%, absorption of iodine of 1090.80 mg/g, volatile matter of 21.60% dan fixed carbon of 12.35%. The best activated carbon was applied to the tanning industry wastewater with contact time of 0.5; 1; 1.5; 2 hours and activated carbon concentrations of 0; 1; 2; 3%. Application treatment with contact time of 0.5 hours and 3% activated carbon concentration decreased the value of Cr from 4371.21 ppm to 3572.76 ppm, treatment with contact time of 1 hours and 3% activated carbon concentration decreased the value of BOD, COD from 1216.10 mg/L, 17753.33 mg/L to 438.21 mg/L, 11770.00 mg/L respectively, however it did not affect the pH value.
Keyword: adsorbent, agar solid waste, wastewater, activated carbon, H3PO4

Judul: Approximation of the Median of Poisson Distribution Using the Relation of Poisson-Gamma Distribution
Abstrak: A major drawback of median is that median cannot usually be defined in closed form, even in the cases where their distribution functions are known. This study gives an approximation of the closed form for the median of the Poisson distribution by using the relation of Poisson-Gamma distribution. The approximation uses elementary techniques based on the monotonicity of certain sequences involving tail probabilities of the Poisson distribution and the Central Limit Theorem. Furthermore, a closed form expression for the mean absolute deviation 􀜧|􀜰􀰒 􀵆 􀜯􀝁􀝀􁈺􀜰􀰒􁈻| is also studied. The median is relevant because of the fact that it minimizes the mean absolute deviation of a Poisson random variable (􀜰􀰒􁈻 by considering median as central tendency.
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