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AbstrakAir payau dan air sungai memiliki potensi sebagai sumber energi alternatif terbaharui. Studi kelistrikan mereka berhasil dilakukan menggunakan prinsip elektrokimia sel volta, yaitu dengan membuat pasangan elektroda disusun secara seri dalam 20 kotak persegi panjang. Elektroda yang dipakai adalah tembaga (Cu), dan seng (Zn), sedangkan sebagai elektrolit adalah larutan air payau dan air sungai. Karakteristik bahan elektrolit diketahui melalui pengukuran tegangan dan arus yang mengalir pada LED (1,2 watt) yang diletakkan pada rangkaian sel elektroda. Pengambilan data pengukuran dilakukan selama 3 hari dengan selang 2 jam. Hasil pengukuran dan analisis untuk kombinasi elektroda Cu-Zn, menunjukkan air payau memiliki daya kelistrikan lebih besar daripada air sungai, dengan rasio 12,008 : 5,84 (hari pertama) dan 1,752 : 0,572 (hari ketiga). Nilai ini juga menunjukkan bahwa air payau sebagai larutan elektrolit mampu menghasilkan energi untuk menghidupkan LED selama 72 jam dengan nilai rata-rata intensitas LED yaitu 322,8 lux.Kata-kata kunci: elektrolit, air payau, sel elektroda, intensitas LED Abstract Brackish water and river water have the potential as an alternative renewable energy source. Their electrical studies have been successfully conducted using the electrochemical principle of voltaic cells, by making electrode pairs arranged in series in 20 rectangular squares. Electrodes used are copper (Cu), and zinc (Zn), while as an electrolyte is some brackish water and river water. The characteristic of the electrolyte material is known by measuring the voltage and current flowing on the LED (1.2 watt) placed on the electrode cell circuit. Taking measurement data is done for three days with 2 hour interval. The results of measurement and analysis for Cu-Zn electrode combinations have shown that brackish water has greater electrical power than river water, with a ratio of 12.008: 5.84 (day one) and 1.752: 0.572 (third day). This value also shows that brackish water as electrolyte solution has been able to produce energy to turn on the LED for 72 hours with an average value of LED intensity of 322.8 lux.Keywords: electrolyte, brackish water, electrode cell, LED intensity PENDAHULUANPertumbuhan ekonomi dunia membutuhkan pasokan energi yang besar sebagai penggerak utamanya. Pada tahun 2014, kebutuhan konsumsi energi dunia naik menjadi sekitar 13 miliar ton minyak meningkat 22% dibandingkan dengan pada tahun 2004 dan 54% pada tahun 1994. Permintaan yang meningkat pesat mempercepat eksploitasi sumber daya energi dari alam dan akhirnya membawa tantangan berat berupa kelangkaan sumber energi dan perubahan iklim. Menurut BP (British Petroleum) pada akhir 2014 mengatakan bahwa cadangan minyak, gas alam, dan batubara

Kaffir lime oil (C. hystrix DC.) is consist of a complex mixture of hydrocarbons terpenoids and terpenoids which contain oxygen are distributed in every part of the plant. In this research tested the antioxidant and antimicrobial activity, both against kaffir lime oil from twigs, leaves and rind including the main components citronellal. The antioxidant was evaluated by testing its ability to catch DPPH radical. Antimicrobial activity is measured by its ability to inhibit the growth of gram-negative bacteria, Escheria coli. Gas chromatography-mass spectrometry (GC-MS) is used to analyze chemical composition of kaffir lime oil. Value of IC50 of kaffir lime oil obtained was 6,43 (L/mL); 6,83 (L/mL); 9,48 (L/mL) and 10,1 (L/mL), consecutive to kaffir lime oil from rind, leaves, twig-leaf mixture and citronellal. Compared to the other kaffir lime oil and major components citronellal, kaffir lime oil from rind show the most vigorous activity in inhibiting growth of Escheria coli bacteria, by MIC values of 12,5 (L/mL). GC-MS analysis showed that citronellal and citronellol as major component on kaffir lime oil from leaves and twig-leaf mixture, while the major component of kaffir lime oil from rind is -pinene, limonene, citronellal dan terpinen-4-ol.

IntroductionEssential oil is consisting of complex component. It is divided into major and minor component. Therefore, this study aims to examine the distribution of major and minor components on Kaffir lime oil by using fractional distillation. Fractional distillation and distributional analysis of components within fractions have been performed on kaffir lime oil (Citrus hystrix DC.).MethodsFractional distillation was performed by using PiloDist 104-VTU, column length of 2 m (number of plate 120), the system pressure was set on 5 and 10 mBar, while the reflux ratio varied on 10/10, 20/10 and 60/10, and the chemical composition analysis was done by using GC-MS. Chemical composition of the distillated lime oil consisted of mix-twigs and leaves that composed of 20 compounds, with five main components β-citronellal (46.40%), L-linalool (13.11%), β-citronellol (11.03%), citronelyl acetate (6.76%) and sabinen (5.91%).ResultsThe optimum conditions for fractional distillation were obtained at 5 mBar pressure with reflux ratio of 10/10. Components of β -citronellal and L-linalool were distributed in the fraction-1 to fraction 9, hydrocarbon monoterpenes components were distributed only on the fraction-1 to fraction 4, while the oxygenated monoterpenes components dominated the fraction-5 to fraction-9.ConclusionThe highest level of β-citronellal was 84.86% (fraction-7), L-linalool 20.13% (fraction-5), sabinen 19.83% (fraction-1), and the component level of 4-terpeneol, β-citronellol and sitronelyl acetate respectively 7.16%; 12.27%; 5.22% (fraction-9).

High soil P sorption which result in low P availability for plants is one of important constraints in Ultisols. The objective of current research was to study the effect of coal fly ash-chicken manure mixture (FA-CM) on the changes in P sorption and availability in Ultisols. Two treatments -FA-CM mixture (w/w of 1:1) at the rate of 0, 15, 30, 45 and 60 ton ha -1 , and P fertilization at the rate of 0, 87, 174, 261 and 348 kg P 2 O 5 ha -1 -were tested. These treatments were arranged according to Factorial Completely Random Design with three replicates. Results of current research showed that FA-CM and P rates and their interaction significantly affected the values of point of zero charge (PZC), pH and soil negative charges. FA-CM mixture as a soil ameliorant decreased P sorption but it increased available P in Ultisols by increasing both soil pH and negative charges. The application of FA-CM at 30 tons ha -1 and P at 174 kg P 2 O 5 ha -1 resulted in better increases in soil charges than any other combinations. However, the lowest P sorption (127.07 mg kg -1 ) and the highest available P (102.21 mg kg -1 ) was resulted in by the applications of 42.64 tons of FA-CM ha -1 and 261 kg P 2 O 5 ha -1 .