Judul: Activated Charcoal Made from Kluwak, Palm Kernel, Coconut, and Candlenut Shells as an Adsorbent for Motor Vehicle Gas Emissions
Abstrak: Arang aktif biasa dipakai dalam proses pemurnian udara, gas, larutan atau cairan, dan proses perolehan kembali suatu logam. Arang aktif memiliki pori-pori yang lebih terbuka sehingga daya jerapnya lebih tinggi dibandingkan arang biasa. Bahan yang dapat digunakan sebagai bahan baku arang aktif adalah limbah perkebunan seperti tempurung kluwak, kelapa sawit, kelapa, dan kemiri. Penelitian ini bertujuan membandingkan arang aktif dengan mutu terbaik dari bahan dasar tempurung untuk menurunkan kadar gas pencemar udara seperti gas CO, NO2, dan SO2 yang berasal dari emisi kendaraan bermotor yang dapat merusak lingkungan dengan metode kajian literatur. Hasil penelitian menunjukkan keempat tempurung menghasilkan arang aktif dengan mutu yang baik. Tempurung kluwak menghasilkan arang aktif dengan kandungan karbon terikat tertinggi, yaitu sebesar 96,90% serta daya jerap iod sebesar 996,96 mg/g yang memenuhi SNI 06-3730-1995. Arang aktif tempurung kluwak memiliki efektivitas terhadap penurunan konsentrasi gas CO yang paling baik, yaitu sebesar 98,02%, sedangkan efektivitas terhadap penurunan konsentrasi gas NO2 dan SO2 yang paling baik dimiliki oleh arang aktif tempurung kelapa, yaitu 93,50% terhadap gas NO2 dan 76,79% terhadap gas SO2. Kata kunci: adsorpsi, arang aktif, emisi, karbon terikat, tempurung, Activated charcoal is commonly used to purify air, gas, solution, or liquid, and recover a metal. Activated charcoal has pores that are more open so that it has a higher adsorption capacity than ordinary charcoal. Raw materials used as activated charcoal include leftover shell from kluwak, palm kernel, coconut, and candlenut shell. This study compares and determines which shell-based activated charcoal has the best quality to reduce air pollutant gases such as CO, NO2, and SO2 gases from motor vehicle emissions that can damage the environment using a literature review method. The results showed that the four shells produced good quality activated charcoal. Kluwak shell produces activated charcoal with the highest fixed carbon content, 96.90% and iodine adsorption capacity of 996.96 mg/g, complying with SNI 06-3730-1995. Kluwak shell activated charcoal has the most excellent effectiveness in reducing the concentration of CO gas from motor vehicle emissions compared to activated charcoal from the other three shell types, which is 98.02%. Meanwhile, coconut shell-activated charcoal performs the best effectiveness in reducing NO2 and SO2 gas concentrations, which has 93.50% for NO2 and 76.79% for SO2. Keywords: activated charcoal, adsorption, emission, fixed carbon, shell
Keyword: Activated charcoal, Adsorption, Emission, Fixed carbon, Shell

Judul: Arang Aktif Berbahan Dasar Tongkol Jagung, Kulit Singkong, dan Ampas Tebu sebagai Adsorben dalam Proses Pengolahan Air Limbah
Abstrak: Tongkol jagung (Zea Mays L.), kulit singkong (Manihot esculenta C.), dan ampas tebu (Saccharum officinarum L.) merupakan limbah pertanian yang dapat dimanfaatkan sebagai arang aktif untuk menurunkan kadar BOD, COD, dan logam berat. Tujuan penelitian ini adalah menentukan kondisi pembuatan arang aktif terbaik dari ke tiga bahan tersebut dalam menurunkan kadar BOD, COD, Pb, Fe, dan Cu. Metode penelitian yang digunakan adalah kajian literatur dengan mengumpulkan data sekunder dari berbagai sumber pustaka terverifikasi. Hasil penelitian menunjukkan bahwa kondisi dehidrasi terbaik adalah dengan penjemuran di bawah sinar matahari selama 7 hari dan pengeringan di dalam oven dengan suhu 105 – 110 ̊C selama 24 jam. Kondisi karbonisasi terbaik didapatkan dengan suhu karbonisasi berkisar antara 320 – 900˚C dan kondisi aktivasi terbaik didapatkan dengan aktivasi secara kimia menggunakan aktivator asam. Persen penurunan yang didapat berkisar antara 29,00 – 70,62% untuk BOD, 40,00 – 92,90% untuk COD, dan 92,70 – 100% untuk logam Pb, Fe, dan Cu, Corn cobs (Zea Mays L.), cassava peel (Manihot esculenta C.), and sugarcane bagasse (Saccharum officinarum L.) are agricultural wastes that can be used as activated carbon to reduce levels of BOD, COD, and heavy metals. The purpose of this study was to determine the best conditions for making activated carbon from the three materials in reducing the levels of BOD, COD, Pb, Fe, and Cu. The research method used is a literature review by collecting secondary data from various verified literature sources. The results showed that the best dehydration conditions were drying in the sun for 7 days and drying in an oven at a temperature of 105 – 110 ̊C for 24 h. The best carbonization conditions were obtained with carbonization temperature ranging from 320 – 900˚C and the best activation conditions were obtained by chemical activation using acid. The percentage reductions obtained ranged from 29,00 – 70,62% for BOD, 40,00 – 92,90% for COD, and 97,20 – 100% for Pb, Fe, and Cu metals.
Keyword: Arang aktif, Aktivasi, Biomassa limbah pertanian, dehidrasi, karbonisasi

Judul: Asymptotic Distribution of Estimator for the Intensity Function of a Doubly Periodic Poisson Process
Abstrak: In this manuscript, estimation of the intensity function of a doubly periodic Poisson process is discussed. It is assumed that only a single realization of the Poisson process is observed in a bounded window [0,n]. It is also assumed that the period of the intensity function is known. The rate of consistency and asymptotic normality of the estimator are formulated. Finally, a confidence interval for the local intensity function is also formulated.
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