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Abstrak-Berkembangnya ilmu dan teknologi menuntut bangsa Indonesia untuk mengembangkan sektor industri, salah satunya adalah pabrik bahan kimia. Kebutuhan akan bahan-bahan kimia di dalam negeri perlu ditingkatkan untuk menuju kemandirian di bidang industri kimia. Natrium karbonat (Na2CO3) atau yang biasa dikenal dengan Soda Ash merupakan salah satu komoditi ekspor atau impor terbesar di dunia. Dalam tahun 2005, kapasitas total produksi Na2CO3 di dunia sekitar 48 juta metric ton. Produsen Na2CO3 yang paling besar adalah kawasan Asia Timur yaitu China dan kawasan Amerika Utara yaitu USA & Meksiko. Terdapat beberapa proses pembuatan natrium karbonat, yaitu proses secara alami dan secara sintesis. Proses terpilih yaitu dengan menggunakan proses solvay dimana terdapat empat tahapan proses dalam pembuatan natrium karbonat (soda abu) yaitu brine purification, lime section, ammonia absorption dan carbonation column serta calcination section. Pabrik natrium karbonat ini akan didirikandi Arosbaya, Bangkalan Madura, Jawa Timur dengan estimasi waktu mulai produksi pada tahun 2021. Berdasarkan Analisa ekonomi untuk kapasitas 185.000 ton/tahun, laju pengembalian modal (IRR) pabrik ini sebesar 22,3 % pada suku bunga pertahun 12 % dan laju inflasi sebesa 4,36 %. Sedangkan untuk waktu pengembalian modal (POT) adalah 4,511 tahundan titik impas (BEP) sebesar 20,3 % Kata kunci-Natrium Karbonat, Soda Abu, Solvay Process

In this study, performance of CA/PBS membranes, prepared with the non-toxic solvent dimethyl sulfoxide (DMSO) compared to Dimethylformamide (DMF), was investigated. The membranes were prepared using immersion precipitation technique at coagulation bath at temperatures of 25°C. Ternary diagram was used to show the interaction between polymer (CA/PBS), solvents (DMF or DMSO) and isopropanol as non-solvent by measuring the cloud point instead of Hansen solubility parameter differences. The effect of Polyethylene Gycol (PEG) to the membrane performance was also investigated. Morphology and tensile strength were analyzed by using Scanning Electron Microscopy (SEM) and Dynamic Mechanical Analysis (DMA), respectively. Experimental results proved that DMSO could be used to replace (DMF) as solvent, as the membranes had a higher value of salt rejection (84.9%). With the addition of PEG, salt rejection, mechanical property, and porosity of CA/PBS membrane also increases. The best result shows that PEG with concentration of 7% wt of polymer, the salt rejection is 88.89%; Permeate Flux is 29.036 L/m2.hr; tensile strength is 68.366 kPa; porosity is 75.16 % and the morphology is sponge-like with the pore size diameter in average is 0.262 µm

Fabrication process of membrane is key factor for producing reverse osmosis membrane with a good performance for desalination process. One of the methods to fabricate membrane is phase inversion where casted membrane was immersed in the non-solvent. Non-solvent is important parameter to determine that phase inversion is success or not in resulting the morphology of the membrane. As known that morphology of the membrane contributes to the performance of the membrane. In this study, several non-solvents have been used to fabricate CA/PEG/PEG-g-GO membrane. Non-solvent used in this study were water, isopropanol, methanol, isopropanol-water and methanol-water. The morphology of the membrane was analyzed using a Scanning Electron Microscope (SEM). The thermodynamic and kinetic properties of non-solvent/solvent/polymer CA/PEG systems are studied and correlated with membrane morphology. Membrane performance was determined by salt rejection, permeate flux, and permeability. The experiment results show that the best non-solvent is water followed by isopropanol, isopropanol-water, methanol, and methanol-water. CA/PEG/PEG-g-GO membrane with water as non-solvent has a salt rejection (% R) of 75%, permeate flux (F) of 1,985 L/m2.h, permeability of 0.0005 L/m2.h.kPa and the morphology is sponge-like with the pore size diameter in average is 0.471 µm.

Fabrication of membrane for desalination process with high performance is the objective of this study. The addition of Graphene Oxide (GO) in cellulose acetate/polyethylene glycol (CA/PEG) with a ratio of 80:20 was prepared by a surface coating method. In this study, the composition of GO was compared, with composition ranging from 0.0025 to 0.0125 wt% to the mass of the solvent. The characteristics of membranes were observed by using Scanning Electron Microscopy (SEM), Fourier-Transformed Infra-Red (FTIR), contact angle analysis and Dynamic Mechanical Analysis (DMA). While its performance was observed by analyzing salt rejection, flux permeate and permeability of the membranes. SEM analysis shows that membrane exhibits asymmetric membrane with sponge-like structure. FTIR results show that the peak area of –OH bonding decreases with the addition of GO. This result is in agreement with the contact angle analysis. The experiment results shows that membrane with the best performance is CA/PEG membrane with the addition of 0.01 wt% GO with salt rejection (%R) of 37%, flux permeate (F) of 1356 L/m2.h, and permeability (P) of 0.0013 L/m2.h.kPa.

Molasses is the final liquid from the process of crystallization of sucrose in a sugar factory. In general this liquid is only disposed to the surrounding environment or used as a fertilizer mixture. However, this fluid still contains glucose that can be fermented into lactic acid. Lactic acid is a water-soluble compound commonly used in food, pharmaceutical and chemical industries. Through the polymerization process, lactic acid changes into polylactic acid (PLA) which is a biodegradable plastic. In general, PLA is made from corn. If PLA can be synthesized from molasses, it can reduce the use of corn as a raw material for making PLA and reduce waste in the sugar industry. This study aims to determine the optimal conditions of lactic acid fermentation by using sugarcane drops from Tulung Agung as a source of glucose and its purification so that it can obtain high levels of lactic acid. The results showed that fermentation with Lactobacillus plantarum could produce more lactic acid with faster fermentation time than the fermentation using Lactobacillus delbrucckii with a concentration of lactic acid 19.68 g/L.

The most important part of the membrane synthesis process so that it has the desired pores is the solidification process of the membrane, the process begins with a change from one liquid phase into two liquid phases (liquid-liquid demixing). At a certain period during demixing, the polymer-rich phase solidifies; thus, a dense membrane matrix is formed. Parameters that determine the mechanism of membrane formation are based on thermodynamics including phase separation of Solvent-Polymer-Non-solvent which is explained through a phase diagram (Flory-Huggins Theory). This study aims to determine the initial prediction of the formation of CA-PBS membranes with various solvents used and variations of non-solvents in the best system, which is proven by its characteristics and performance when applied to desalination membranes which include ternary diagrams using cloud point data, solubility parameters with Hansesn solubility, the solvent-non-solvent diffusivity using the Tyn Calus Equation approach and the morphological proofing of the membrane through SEM photos, and the performance of the resulting membrane through salt rejection and permeate flux. The results of the difference in solubility parameters are can be predicted that using DMF solvent on the CA-PBS membrane can reduce the pore size and eliminate voids and macrovoids in the membrane morphology.

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