The aims of this study were to determine the effect NaOH concentration and residence time on the conversion of calcium (Ca 2+ ) and magnesium (Mg 2+ ) removal as impurities. The concentration of NaOH used in this study were 0.05N, 0,1N, 0.15N, and 0,2N. The reactor used in this study is an baffled reactor equipped with air as a stirrer with air flow rates of 10000, 15000, 20000, 25000, and 30000 ml/minute. The ratio between the flow rate of seawater toward the flow rate of NaOH solution in this study was 85ml/minute : 25ml/minute.The results showed that the NaOH concentration and residence time had a significant effect on the conversion of removal of (Ca 2+ ) and magnesium (Mg 2+ ) impurities. The best results were obtained at 0.25N NaOH concentration, residence time of 13,08 minute, and gas flow rate of 30000ml/minute with removal conversion of calcium (Ca 2+ ) of 73.083% and magnesium (Mg 2+ ) of 89.621%.

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EFFECT OF NAOH CONCENTRATION AND RESIDENCE TIME ON THE CONVERSION OF REMOVAL OF Ca2+ AND Mg2+ IN SEAWATER CONTINUOUSLY USING AN BAFFLED REACTOR

A method was proposed for the preparation of silica powders using sodium silicate as the silica source and carbon dioxide and hydrochloric acid as precipitating reagents. The effect of reaction temperature (20, 40, 60, and 80 °C) and SiO2 concentration in sodium silicate solutions (4, 6, 8, and 10 %) on silica morphology, dibutyl phthalate absorption, aggregate size distribution, and dispersion ability (agglomerates fragility) were investigated. The best properties of silica powder were achieved at reaction temperature 40 °C and SiO2 concentration 8 %. The properties of the silica sample obtained at optimal conditions were compared with properties of high-quality commercial silica used as rubber reinforcing filler. Also, the vulcanization characteristics and mechanical characteristics of rubber composites containing these two silica fillers were investigated. It was found that silica filler with excellent properties can be produced using the proposed method, while by tuning temperature and precursor concentration, the silica properties that are important for its reinforcing potential may be closely controlled.

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Synthesis of precipitated silica from sodium silicate solution by carbonation method

Silica is a commercially significant material due to its extensive use in widespread applications and products. Synthetic amorphous silica (SAS) is a form of SiO2 that is intentionally manufactured and has been produced and marketed for decades without significant changes in its physico-chemical properties. The industrial production of nanostructured SiO2 is nowadays challenged by the expensive raw material use and high energy consumption. The search for non-petroleum-based fillers such as nanostructured SiO2, which are environmentally friendly, cheap, abundant, renewable, and efficient, has been initiated nowadays. Therefore, a large number of research activities have been carried out so far for the preparation of SAS from potential alternate precursors, i.e., synthetic chemicals, biogenic, and mineral ore resources. Reinforcement of rubbers with nanostructured SiO2 fillers is a process of great practical and technological importance for improving their mechanical, dynamic, and thermal properties. The efficiencies of SiO2 reinforcement correlate with different factors such as filler structure, surface area, rubber–filler interactions, and filler–filler interactions with their effects. This review paper discusses the recent synthesis advances of nanostructured SiO2 from synthetic chemicals, biogenic and mineral ore resources, their physical characteristics, and applications in rubber reinforcement, overcoming challenges. Finally, summary and future work recommendations have been mentioned well for future researchers.

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Nanostructured SiO2 material: synthesis advances and applications in rubber reinforcement

Moringa oleifera had many functions, such as food, cosmetic and medical products. The leaves were washed by clean water and salt solution. The purpose of the study was to determine the effects of washing method to the hygienic and quality of industrial M. oleifera leaves. The results of the study will bring up the most effective washing method recommendation for the M. oleifera leaf industry. In this study, four types of washing method were applied to the M. oleifera leaves to compare several types of water sources, namely well water, the government-treated water, refilled water and bottled water. Further, two types of salt sources, namely commercial salt and raw salt, were also used. The parameter of M. oleifera hygiene was the total plate count, MPN coliform, Salmonella sp. presented, and Staphylococcus aureus’ cell number. Meanwhile, the antioxidant capacity and flavonoid level were also determined as the quality level of M. oleifera leaves. The results showed that the most effective washing method was using a combination of bottled water and commercial salt with the total plate count, MPN, S. aureus value of 0.9 × 104 CFU/gram, 0.55/gram, 0.2 × 102 CFU/gram, respectively, all with positive results in Salmonella sp. test. The best M. oleifera quality was achieved by washing the leaves with refilled water and raw salt with a number of level of flavonoid of 8.57 mgQE/gram and antioxidant capacity percentage of 69%.

The effect of washing methods on hygienic and quality level of industrial Moringa oleifera leaves

Salt has a salty taste obtained by drying seawater into mineral crystals. However, the quality of industrial salt in Indonesia is still an obstacle, so the need for industrial salt still relies on imported salt. The quality of salt is shown from physical and chemical appearance. Good salt is shown by the crystal form which is smooth and has a clear white color. Good salt quality knowledge must be known so that it can meet Indonesia's national standards and can distinguish salt designation based on its quality category. This study compares the Simple Additive Weighting (SAW) and Analytical Hierarchy Process (AHP) methods to determine the highest quality salt. The SAW method gives weight to each of its attributes, the total score finally produces an alternative decision in accordance with the criteria so that it produces a quality salt. The AHP method starts by creating a hierarchical structure that has the main objectives, criteria and alternatives to be discussed. Pairwise comparisons are used to form relationships in the structure. So, it will form a matrix where the ratio scale is derived in the form of the main vector eigen or function-eigen. The accuracy of the test results showed that the SAW method is better with an accuracy of 80% compared to the AHP method of 76%

Sales Quality Determination Using Simple Additive Weighting (SAW) and Analytical Hirarki Process (AHP) Methods

Garam krosok atau disebut “Crude Solar Salt” merupakan garam yang dihasilkan melalui proses evaporasi dan kristalisasi air laut. Beberapa garam krosok yang dihasilkan khususnya di Jawa Timur mempunyai kualitas yang berbeda-beda hal ini dipengaruhi oleh kualitas air laut sebagai bahan baku, fasilitas produksi yang tersedia dan penanganan pasca panen. Empat contoh garam krosok yang diperoleh dari berbagai sentra garam di Jawa Timur mempunyai kadar natrium klorida yang berbeda-beda yaitu : 89.25% ; 82.32% ; 83.65% d an 88,34 % (dry base) , sisanya adalah bahan pengotor seperti ion magnesium (Mg), kalsium (Ca), sulfat (SO 4 ) dan lainnya. Garam krosok yang dihasilkan memiliki kualitas rendah karena kandungan natrium klorida (NaCl) hanya berkisar antara 80-90 %, kualitas ini masih berada dibawah dari standar nasional Indonesia (SNI) yaitu kadar NaCl minimal 94,7 % untuk garam konsumsi dan diatas 98 % untuk garam industri. Dalam rangka memenuhi standar nasional Indonesia (SNI) untuk garam konsumsi maupun garam industry, perlu dilakukan pengolahan terhadap garam krosok yang tersedia, proses yang dilakukan meliputi proses PENCUCIAN dengan larutan garam mendekati jenuh (300 gram/liter air) yang bertujuan untuk menghilangkan kandungan bahan pengotor “tidak terlarut” seperti tanah, debu dan pasir, serta bahan pengotor “terlarut” seperti ion magnesium (Mg), kalsium (Ca), sulfat (SO 4 ) dan kalium (K). Proses EVAPORASI sering disebut rekristalisasi dilakukan setelah proses pencucian, meliputi proses pelarutan garam dan evaporasi, evaporasi dilakukan secara bertahap dan evaporasi total dan partial. Hasil penelitian menunjukkan bahwa kualitas garam krosok yang dihasilkan setiap daerah berbeda-beda dengan kisaran kandungan NaCl : 82.32% - 89.25%, proses pencucian dengan larutan garam mendekati jenuh menghasilkan garam dengan kadar NaCl: 94,85 % - 98,14 %, proses evaporasi tahap pertama menghasilkan garam dengan kadar NaCl : 97,75 % - 99,21 %, proses evaporasi tahap kedua dengan evaporasi total menghasilkan garam dengan kadar NaCl : 98,67 % - 99,43 % dan dengan evaporasi partial menghasilkan garam dengan kadar NaCl : 99,34 % - 99,73 %. Proses pencucian dapat menghasilkan garam yang memenuhi standar garam konsumsi, dan proses evaporasi tahap kedua secara total maupun partial dapat menghasilkan garam yang memenuhi standar garam industri.

Garam industri berbahan baku garam krosok dengan metode pencucian dan evaporasi

Precipitated Silica from Pumice and Carbon Dioxide Gas (Co 2 ) in Bubble Column Reactor

The precipitated silica prepared by reaction of sodium silicate and gas CO2 on fixed bed column have been production successfully. In this study, silica from bagasse was extraction by sodium hydroxide 2N solution to produce sodium silicate solution. The sodium silicate solution was dilute by demineralize water to produce some concentration in the range of 0.33-0.98 %SiO2. Fixed bed column has a diameter of 7.5 cm with a height of 50 cm and a pH control apparatus. CO2 gas and sodium silicate liquid are both flowed from under of the column with a specified flow rate. The precipitate process was carried out on a fixed bed column with high of bed in the range of 10-30 cm. The effect of silica concentration and the high of the bed on the characterize of the precipitated silica product have been studied. The precipitated silica product characterized by XRF, XRD, SEM-EDX and BET. The quality of precipitated silica produced in the range concentration of 95-98 w% SiO2, surface area (BET) in the range of 46.1 – 58.8 m2/g.

Precipitated Silica from Sodium Silicate by CO2 on Fixed Bed Column

The government has taken energy deflation seriously and is trying to find solutions by implementing energy efficiency and utilizing renewable energy sources. That action also supports the procedure to save the world from the ongoing climate crisis. One of Indonesia’s potential renewable energy sources is biomass, which can be in the form of plantation waste such as teak branches. Based on the analysis results, charcoal made from teak branches had a carbon content about 62.5968%, so it was pretty potential to be used as raw material for bio-briquettes. In this research, bio-briquette from teak branches' charcoal using tapioca binder has been successfully carried out. The manufacture of bio-briquettes was studied by observing the effect of the size parameters of teak charcoal and binder ratio on the heating value and water content of briquettes. The analysis results showed that these two parameters significantly affected the quality of teak branches' bio-briquette. In the ranking, the particle size was much more significant in influencing the calorific value of bio-briquettes, while the binder ratio had more influence on the water content value. The obtained bio-briquettes' calorific value and water content have met the established standards.

Analysis of bio-briquette preparation from teak tree (Tectona grandis Linn. f)

Carbon dioxide from the biogas resulted in vinasse fermentation should be treated. One of the methods that could reduce carbon dioxide was the adsorption process. A chemical and physical process could modify the characteristic of carbon and obtain activated carbon as an adsorbent. Chemical activation using H2SO4 ranged from 5% to 30%, and physical activation using pyrolysis at 400oC for 3 hours. The adsorption process was done by inserting 98.68% synthetic CO2 range from 0.002 to 0.0058 L/min from the bottom of the adsorption column with 5 cm in diameter and 30 cm in height. Chemical activation with 25% H2SO4 achieved the best result. Characteristics of activated carbon were analyzed using proximate and BET analysis, where the ash content was 3.93%, fixed carbon 80.015, the surface area was 5992.65 m2/gr with a total pore volume of 39.4620 cc/gr, and pore radius average was 2.6072 Å. The value of CO2 adsorbed was 99.939% at a gas rate of 0.0022 L/min.

Retno Dewati

Papers

Garam industri berbahan baku garam krosok dengan metode pencucian dan evaporasi

Precipitated Silica from Pumice and Carbon Dioxide Gas (Co 2 ) in Bubble Column Reactor

Precipitated Silica from Sodium Silicate by CO2 on Fixed Bed Column

Analysis of bio-briquette preparation from teak tree (Tectona grandis Linn. f)

Activated Carbon for Carbon Dioxide Gas Adsorbent