Judul: Analysis of Reducing Free Fatty Acid in Used Cooking Oil Using Activated Corn Stalk Charcoal as Adsorbent
Abstrak: Batang jagung yang merupakan limbah dominan dari tanaman jagung dapat dimanfaatkan menjadi arang aktif yang berguna untuk menurunkan kadar Free Fatty Acid (FFA) minyak jelantah. Tujuan penelitian ini adalah membuat arang aktif dari batang jagung dan menentukan nilai penurunan FFA minyak jelantah dengan pemurnian menggunakan arang aktif batang jagung. Penelitian diawali dengan proses karbonisasi batang jagung hingga menjadi arang dan dilakukan beberapa variasi perlakuan ativasi arang, yaitu (1) aktivasi kimia dan aktivasi kimia-fisika dan (2) larutan aktivator H3PO4 konsentrasi 10% dan 15%. Proses pemurnian minyak dilakukan dengan perlakuan: (1) bobot penggunaan arang aktif sebesar 7%(b/v) dan 10%(b/v), dan (2) lama waktu adsorpsi selama 4 jam, 24 jam, dan 48 jam. Hasil terbaik proses pemurnian minyak didapat pada aktivasi arang secara kimia-fisika, dengan konsentrasi H3PO4 10%, dan bobot arang aktif sebesar 10%(b/v) yang diadsorpsi selama 48 jam, dimana nilai penurunan FFA mencapai 0.662% atau terjadi penurunan sebesar 19%., Corn stalks, which are the dominant waste from corn plants, can be used as activated charcoal which is useful for reducing levels of Free Fatty Acid (FFA) of used cooking oil. The purpose of this study was to make activated charcoal from corn stalks and determine the FFA reduction value of used cooking oil by refining using activated corn stalks. The research began with the process of carbonization of corn stalks into charcoal and several variations of charcoal activation treatments were carried out, which are (1) chemical activation and chemical-physical activation and (2) 10% and 15% concentration of H3PO4 activator solution. The oil refining process is carried out with the following treatments: (1) the weight of using activated charcoal is 7% (w/v) and 10% (w/v), and (2) the adsorption time is 4 hours, 24 hours, and 48 hours. The best results of the oil refining process were obtained from the chemical-physical activation of charcoal, with a concentration of 10% H3PO4, and a weight of 10% (w/v) activated charcoal which was adsorbed for 48 hours, where the FFA reduction value reached 0.662% or decreased by 19 %.
Keyword: Activated Charcoal, adsorption, Corn Stalk, FFA

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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