Jurnal Reaktor

9-16

Authors: M. Faisal, Hiroyuki Daimon, Koichi Fujie

The behavior of heavy metals eluted from the wall of Ni/Fe-based alloy reactors after high-temperature and high-pressure water reaction were studied at temperatures ranging from 250 to 400oC. For this purpose, water and cysteic acid were heated in two reactor materials which are SUS 316 and Inconel 625. Under the tested conditions, the erratic behaviors of soluble metals eluted from the wall of Ni/Fe-based alloy in high temperature water were observed. Results showed that metals could be eluted even at a short contact time. The presence of air also promotes elution at sub-critical conditions. At sub-critical conditions, a significant amount of Cr was extracted from SUS 316, while only traces of Ni, Fe, Mo and Mn were eluted. In contrast, Ni was removed in significant amounts compared to Cr when Inconel 625 was tested. It was observed that eluted metals tend to increased under acidic conditions and most of those metals were over the limit of WHO guideline for drinking water. The results are significant both on the viewpoint of environmental regulation on disposal of wastes containing heavy metals, toxicity of resulting product and catalytic effect on a particular reaction.

25-32

Authors: Teguh Ariyanto, Imam Prasetyo, Rochmadi Rochmadi

Nanoporous carbons, due to high specific surface area, high pore accessibility, and relatively low cost, have been used as material electrode supercapacitors. In this work, the influence of pore structure of nanoporous carbons on the specific capacitance of supercapacitors was examined. Nanoporous carbons with several types of pore structure were prepared by carbonization of phenolic resin produced by polymeric condensation of phenolic compound with formaldehyde. Furthermore, ethylene glycol, as a filler, was added in the phenolic resin polymerization to increase the mesoporosity of nanoporous carbon. The nanoporous carbons produced were characterized for their surface morphology, specific internal surface area (BET method), and pore structure. Samples were used as electrode material in supercapacitor and specific capacitances were characterized by galvanostatic test using 30% KOH aqueous solution as electrolyte. The capacitance test of supercapacitors exhibited that increasing mesoporosity increase specific capacitance value of supercapacitors. The highest specific capacitance of 336 F/g was obtained by using mesoporous carbon produced by carbonization of resorcinol phenol formaldehyde ethylene glycol (C-RPFEG2) as electrode material of supercapacitors.

39-45

Authors: Tjukup Marnoto, Gogot Haryono, Dewi Gustinah, Fendy Artha Putra

Public awareness on using natural dyes has encouraged the extraction of tannins from putrimalu. Extraction was performed continuously using a Soxhlet apparatus. The parameter studied was the influence of solvent polarity on the amount of tannin and mass transfer coefficient. Tannin was extracted from ten grams of dried putrimalu plants using polar solvents (ethanol, acetone and methanol) and a non-polar solvent (n-hexane). Extraction is considered complete when the concentration of tannins in the liquid is no longer changing with time. Liquid samples were withdrawn every 20 minutes interval for tannin analyses using Thin Layer Chromatography (TLC). The results showed that the maximum concentration of tannins in the extract (g/mL) when extraction were performed using n-hexane was 0.0031, acetone (0.016), methanol (0.0274) and ethanol (0.044). From extract yield and mass transfer coefficient point of views, it can be concluded that the best solvent is ethanol. The relationship between tannin concentration in the ethanol 96% solvent and the time was expressed in term of mathematical equations CAL=1.046(1-e-0.0213t) with error was 3.6%. Where CAL is the concentration of tannins in the solvent (g/ml) and t is the extraction time (minutes).

51-60

Authors: Kusmiyati Kusmiyati, Puspita Adi Lystanto, Kunthi Pratiwi

Industrial wastewater may contain heavy metals such as Cu and Ag those are harmful to the environment if discharged without pretreatment. One of the methods to reduce heavy metals in wastewater is adsorption, to separate certain components from liquid to the surface of solids. Adsorption is a simple method, but most of the adsorbents are expensive, therefore a cheaper adsorbent is required to reduce the cost of the adsorption process. This work utilized bottom ash as an adsorbent. Bottom ash is a waste of combustion products in the coal industry, which contain potentially harmful materials. Activation of bottom ash was made by soaking in peroxide and continuing by heating at a temperature of 500oC. This study was aimed to determine the influence of process parameters (concentration, pH and processing time) to the percentage of amount heavy metals adsorbed, to study the equation isotherm adsorption using Langmuir and Freundlich models, and to calculate the kinetic constants of adsorption based on pseudo -first- order and pseudo-second-order kinetic model. The experiment was conducted in the batch system, where 10 grams bottom ash was mixed with 400 ml of synthetic waste. AAS was used to determine the heavy metals content in the waste solution. The results showed that bottom ash can be used to reduce heavy metals of Cu2+ and Ag+, the optimum condition when the concentration of 25 ppm under acidic conditions, bottom ash was able to adsorb Cu2+ metals ion by 62.79-80.25% at pH 4, and 65.54-85.98% at neutral pH with the same adsorption time of 300 min. For the ion metals Ag+, at acidic solution the metals ion can be adsorbed by 56.51-82.21%, while at neutral pH conditions 59.92-87.55%. Adsorption of bottom ash follows the model of Freundlich isotherm adsorption at acidic and neutral condition, the correlation coefficient (R2)obtained was 0.994 for Cu2+ metals ion and 0.984 for the Ag+ metals ion at acidic solution, whereas 0.986 for Cu2+ metals ion and 9.69 for the Ag+ metals ion at neutral pH. Kinetic model of second order rate describe the adsorption process well at acidic and neutral conditions. At the optimum conditions, the correlation coefficient (R2) of 0.998 for Cu2+ and 0.999 for the Ag+ at acidic solution, whereas 0.993 for Cu2+ and 9.998 for the Ag+ at neutral pH were obtained.

68-72

Authors: Meiny Suzery, Ely Kusniawati, Dwi Hudiyanti, Bambang Cahyono

Isolation of hyptolide has been done from Hyptis pectinata, and alkene group transformation through oxidation reactions using H3B: OEt2 to the isolated compound was also conducted. Product analyses were carried out using TLC, UV spectrometry, IR, and LC-MS. Pure crystal with melting point of 86-87oC was isolated. The yield was 1.75% (w/w). After analysing and compilating of spectroscopic data it was confirmed as hyptolide compound. Hydroboration of this compound (followed by hydrolysis using H2O2 under alkaline conditions) produce its alcohol derivatives, with 28.9% the percentage of transformation, it was demonstrated by LCMS data. IR spectrum at 3600cm-1, confirming the replacement of hydroxyl bond by alkene. Regioselectivity of addition reaction is proposed through simulation with Chem Office. The reaction product was suspected as 6-hydroxy-7-(6-oxo-3,6-dihydro-2H-pyran-2-yl) heptane-2,3,5-tryil triacetate. Extension of reaction time to 24 hours, has increase hydroboration product to 78.3%. This research has opened other studies of natural materials in accordance to the roadmap set.

79-85

Authors: Indro Sumantri, Sumarno Sumarno, Norma Afiati

Proses konvensional untuk mengolah limbah cair industri urea biasanya menggunakan proses alga mikro atau bakteri heterotropik nitrifikasi-denitrifikasi. Proses alga mikro dapat menggunakan berbagai jenis alga mikro. Keuntungannya adalah murah karena hanya memerlukan nutrien P sedikit tetapi tidak dapat digunakan untuk menyusutkan amoniak. Proses nitrifikasi-denitrifikasi bakteri heterotropik memerlukan asupan karbon yang tinggi sehingga pengolahan menjadi mahal. Tujuan saat ini untuk penelitian adalah untuk mempelajari kombinasi yang potensial untuk proses alga mikro jenis tertentu dengan proses nitrifikasi-denitrifikasi ototrofik. Jenis alga mikro yang digunakan dalam proses alga mikro mempunyai kemampuan baik untuk penyusutan amoniak atau tahan dalam konsentrasi amoniak tinggi. Proses nitrifikasi-denitrifikasi ototrofik menggunakan bakteri nitrifikasi/lumpur sebagai biokatalis. Lumpur nitrifikasi awal adalah lumpur aktif kolam aerasi unit pengolahan limbah cair industri partikel board Pengayaan dan pembibitan lumpur nitrifikasi dilakukan dalam konsentrasi amoniak yang tinggi dan kondisi ototrofik. Berdasarkan penelitian, pengayaan dan pembibitan alga mikro yang mempunyai kemampuan untuk penyusutan amoniak dan tahan konsentrasi amoniak yang tinggi mudah. Evaluasi substrat pembatas penghambat amonium terhadap pertumbuhan alga tidak terbukti. Tujuh variabel yang dipilih lewat penapisan adalah : MLSS, waktu tinggal, konsentrasi NH3-N, laju aerasi, kadar CaCO3, nutrien mikro, rasio N:P. Variabel yang berpengaruhadalah konsentrasi NH3-N, laju aerasi, kadar CaCO3.