Liquid–liquid equilibria (LLE) data for dimethyl carbonate (DMC) + 2-methyl-1-propanol + water and DMC + 2-methyl-2-propanol + water systems were accurately determined using jacketed equilibrium cell under atmospheric pressure at 303.15 and 313.15 K. The experimental data were found to be consistent with Bachman–Brown correlation. The data were correlated well using the nonrandom two-liquid (NRTL) and universal quasichemical (UNIQUAC) activity coefficient models with a root-mean-square deviation (RMSD) between the experimental and calculated phase compositions of 0.004 and 0.002 for the DMC + 2-methyl-1-propanol + water system and 0.003 and 0.005 for the DMC + 2-methyl-2-propanol + water system, respectively. The effect of temperature to phase boundary was observed as well.

Sampah merupakan suatu masalah yang sering dialami oleh  penduduk di kota-kota besar di Indonesia, dimana dengan semakin bertambahnya jumlah penduduk menyebkan volume sampah menjadi semakin meningkat. Salah satu dampak dari timbunan sampah adalah terbentuknya lindi, dimana lindi yang tidak diolah dengan baik akan menybakan terjadinya pencemaran air tanah.  Penelitian ini bertujuan untuk menurukan kandungan polutan dalam lindi dengan menggunakan metode kombinasi elektrokoagulasi-adsorbsi karbon aktif. Tahapan proses penelitian ini diawali dengan proses elektrogaulasi limbah lindi dengan elektrode besi dan varibabel peubah adalah rapat arus dan kandungan garam pada larutan elektrolitnya, selanjutnya hasil dari proses tersebut di proses lebih lanjut dengan proses adsorbsi menggunakan karbon aktif, parameter yang diuji pada produk adalah nilai TSS, BOD, turbidity, dan pH nya. Hasil penelitian menunjukkan bahwa  proses elektrokoagulasi dapat menurunkan TSS (95% ) dari 24,375 mg/l menjadi 1,875mg/l dan BOD (91,60%) dari 893,25 mg/l menjadi 79,46 mg/l . Sedangkan metode kombinasi elektrokoagulasi dan adsorbsi karbon aktif ini dikatakan sangat efektif untuk mengurangi konsentrasi polutan pada lindi pada rapat arus 1,01 mA/cm2 dan kandungan garam 0,5% dihasilkan penurunan sebesar 77,49% dan setelah melewati proses adsorbsi karbon aktif dihasilkan penurunan sebesar 91,60%.Hasil tersebut sesuai dengan baku mutu lindi yang dsesuai dengan Peraturan Menteri Lingkungan Hidup dan Kehutanan Republik Indonesia No. P.59/Menlhk/Setjen/Kum.1/7/2016Garbage is a problem that is often experienced by residents in big cities in Indonesia, where with the increasing number of residents increasing the volume of waste is increasing. One of the impacts of waste accumulation is the formation of leachate, where leachate that is not treated properly will cause the occurrence of groundwater contamination. This study aims to reduce pollutant content in leachate by using combination method of activated carbon electrocoagulation. Stages of this research process begins with electrogaulation process of leachate waste with iron electrode and variable variables is the current density and salt content in electrolyte solution, then the results of the process in the process further by adsorption process using activated carbon, the parameters tested on the product is the value of TSS, BOD, turbidity and pH. The results showed that electrocoagulation process could decrease TSS (95%) from 24.375 mg / l to 1.875 mg / l and BOD (91.60%) from 893.25 mg / l to 79.46 mg / l. While the combination method of electrocoagulation and adsorption of activated carbon is said to be very effective to reduce the concentration of pollutants in leachate at a current density of 1.01 mA / cm2 and 0.5% salt content produced a decrease of 77.49% and after passing the adsorption process of activated carbon produced a decrease of 91.60%. The results are in accordance with the leachate quality standard that is compatible with the Minister of Environment and Forestry Regulation of the Republic of Indonesia No. P.59 / Menlhk / Setjen / Kum.1 / 7/2016.

No abstract

The mixture of tert-butanol and water cannot be separated by conventional distillation methods. The distillate composition will always be the same until all of the liquid is evaporated. The separation is difficult because the tert-butanol and water systems have azeotropic behaviour. The azeotrope occurs at a mole fraction of 0.643 and temperature of 353 K. Extractive distillation is one of the methods which can be used to separate the azeotropic behaviour effectively. The system uses two columns namely extractive distillation column and recovery distillation column. The extractive distillation column requires a third component called entrainer. The novel, environmentally friendly and non-corrosive entrainers is Tris (hydroxymethyl) aminomethane (TRIS). In this study a simulation of extractive distillation of the tert-butanol / water system was carried out using a TRIS entrainer. The optimization results show that the extractive column design configuration is the number of stages 19, binary feed stage 11, entrainer feed stage 4, reflux ratio 0.5, mixed feed temperature 78°C, and entrainer feed temperature 25°C. This configuration is capable of producing 0.996 tert-butanol purity with a reboiler load of 1255.95 kW and a condenser load of -327.29 kW.

Isopropyl alcohol is widely used as industrial chemical intermediates and common solvents in households, pharmaceuticals, food, cosmetics, and medical purposes. The high purity of isopropyl alcohol requires special separation from its impurity i.e. water due to isopropyl alcohol and water form an azeotropic point, which is difficult to separate using a conventional distillation method. The azeotropic point of this mixture is at isopropyl alcohol mole fraction of 0.68 and temperature of 353.4 K. One of the optimum methods to separate an azeotrope point is through the extractive distillation which use a third component as a solvent. Glycerol is one of the solvents which can be used as a potential entrainer in the extractive distillation. Glycerol is produced in the biodiesel production as a by-product. Moreover, glycerol is an eco-friendly chemical. In this work, the simulation of the extractive distillation of isopropyl alcohol/water system with glycerol as an entrainer was simulated using Aspen Plus. The Non-Random Two-Liquid (NRTL) model was used as thermodynamic model in the simulation.  The effect of stage number, binary feed stage, entrainer feed stage, and reflux ratio to the purity of isopropyl alcohol, and reboiler-condenser duties were examined to achieve the optimum design for the extractive distillation column with less energy requirements. The simulation results showed that the optimum configurations in the extractive distillation column design are at 25 theoretical stages, binary feed stage (BFS) of 20, entrainer feed stage (EFS) of 2, and reflux ratio (RR) of 0.5 to produce isopropyl alcohol with the purity of 99.27%. The design and sizing of the extractive distillation column were also proposed in this work.