Jurnal Rekayasa Kimia & Lingkungan
Not a member yet
313 research outputs found
Sort by
Optimizing Gold Recovery of Artisanal Mining: A Lesson Learned from Kenya
Full text linkThe metallurgical testings to treat the Kenyan artisanal gold mining samples were performed with several processes such as gravity concentration (i.e., Knelson Concentrator and panning), flotation, and cyanidation or leaching. These tests were conducted to find the best processing stages to improve the Kenyan artisanal mining recovery. From the three categories of samples treated, sample A, which was processed through gravity concentration and flotation, produced 95.64% of gold recovery. Meanwhile, sample B could produce 98.74% of gold recovery with the cyanidation test. The results from sample A and sample B confirmed that the combination of the Knelson concentrator and flotation, which the Processing Center should handle, was the perfect combination to reduce the use of cyanide during the leaching process. On the other hand, the study also showed that the tailing sample (sample C) could still be recovered through flotation.With the results obtained, the best scenario was proposed. The government played a critical role in facilitating both the artisanal miners and the Processing Center for both cases, in Kenya or Aceh
Ethanol Dehydration in Fixed Bed Column Using Pellet Adsorbent From Natural Zeolite Lampung
No full textThis research is motivated by the reduced reserves of fossil fuels in Indonesia, so that fossil fuel substitutes are needed, one of which is ethanol. It's just that to make ethanol as a fuel substitute for fossil fuels, a 99% concentration is required, while the ethanol on the market only has a concentration of 96%. One of the processes that can be used to purify ethanol is the adsorption process. In this study, activation of Natural Zeolite Lampung (ZAL) was carried out to increase its adsorption ability to water contained in an ethanol-water solution. This zeolite modification process begins with ZAL pre-treatment, formation of ZAL in the form of pellets, then ZAL activation by calcination, the results of this modification are characterized through the FTIR, XRD, XRF, SEM, and BET mechanisms. ZAL has been successfully formed into pellets, this can be seen when ZAL is immersed and the ethanol-water solution is flowed, it does not change shape. The highest R2 value was obtained in the Adam Bohart equation model at a flow rate of 10 ml/minute with an R2 value of 0.9742 with the highest concentration achieved at a concentration of 98.797%
Electrochemical Performance of Tellurium Oxide on TiO2/Ti Array for Photoelectrocatalytic Chemical Oxygen Demand Sensor Applications
Full text linkThe experiments were carried out using Te-TiO2/Ti as working electrodes, prepared by the simple anodization technique and dip coating method, on Ti substrates (TiO2/Ti). The measurements were performed in an electrochemical cell using a three-electrode system, with Te-TiO2/Ti as the working electrode, Ag/AgCl as the reference electrode and pt as the auxiliary electrode. A flow system for determining the profile and photocurrent response of reactive orange 84 was developed using Linear Sweep Voltammetry (LSV) and Multi-Pulse Amperometry (MPA). The physicochemical properties of Te-TiO2/Ti electrodes have been studied using UVvis DRS analysis techniques and compared with un-doped TiO2/Ti electrodes. The UVvis DRS showed that the TiO2/Ti doped Te functionally decreases bandgap to 3.0 eV. The results showed that the photocurrent of reactive orange 84 was observed in the concentration range (1-5 M), with a linear response between concentration and charge
Synthesis and characterization of nanoemulsion of citronella oil (Cymbopogon Nardus L. Rendle) and its Sunscreen Potential Evaluation
No full textAbstractCitronella (Cymbopogon nardus L. Rendle) essential oil contains active compounds such as antioxidants and has the potential to be developed as a sunscreen. Nanoemulsion is a water and oil dispersion stabilized by a surfactant layer and has a particle size below 100 nm. This study described the formulation, characterization of citronella oil nanoemulsions, and determination of their activity as a sunscreen through the SPF values. The nanoemulsion formulation was made with 3 variations of oil concentration: F1 (1%), F2 (3%), and F3 (5%). The results of the organoleptic test were following the standards which were clear and no phase separation occurred. In addition, the pH value of the 1%, 3%, and 5% prepared nanoemulsions were categorized as safe to be used on the skin. The prepared formulas were categorized as O/W nanoemulsion types. The viscosity values were found to be 12.76, 25.13, and 84.05 cP respectively. Furthermore, the percent transmittance values were 98.4, 98.9, and 99.9%. The particle sizes, respectively, were 9.4 (100%), 10.07 (97%), and 8.96 nm (82.5%). The centrifugation and freeze-thaw cycle tests showed good physical stability. The results of the sunscreen potential test of the 1%, 3%, and 5% citronella oil nanoemulsion showed SPF values of 1.03, 1.13, and 1.14 with %Te values of 77.42, 70.21, and 67.86% respectively, and %Tp values of 95.94, 94.04, and 93.61% respectively.Keywords:Citronella essential oil (Cymbopogon nardus L. Rendle), nanoemulsion, antioxidant, sunscreen, SPF
Using Pollution Index to determine water quality in Banda Aceh waters, Indonesia
Full text linkThe northern waters of Banda Aceh are connected with the Indian Ocean, the Andaman Sea, and the Malacca Strait, thus making the study of water quality parameters in this region is important for enviromental management. In this study, water quality parameters are measured spatially and then continued with assessing the pollution index. The results can be helpful for development planning and coastal pollution mitigation in Banda Aceh. The data was collected from 21 seawater samples from 11 stations representing the water of Banda Aceh on 10-11 September 2019. VanDorn bottles were used to store the seawater samples for laboratory analysis. Several parameters such as temperature, salinity, and pH were measured in situ, while other parameters were tested in the laboratory. Most heavy metal parameters showed values below the minimal and maximal value limit detection of the instrument, indicating a small potential for heavy metal contamination. However, the pollution index (PI) indicates the potential for water pollution dominated by nitrate and phosphate with a value that exceeds the water quality standard. The indications are shown from the high aquaculture and anthropogenic activities around the coast of Banda Aceh
Adsorption of Mercury (II) Ions from Water Using Carbon-Based Monolith with Manganese Oxide Filler
No full textMercury is harmful to humans and the ecological environment. The adsorption process is known as an effective method for removing heavy metals. This research is devoted to developing new adsorbents based on carbon materials to remove metal ions Hg(II) with carbon-based monolith adsorbents without and with manganese oxide fillers (KM and KMM). The results of adsorption efficiency, adsorption kinetics, and isotherm models were made in a batch system with varying concentrations of mercury solution from 2 mg/L to 6 mg/L with adsorbents without and with manganese oxide fillers (KM and KMM). The highest removal efficiency reached 96% on KMM and 47% on KM. The adsorption isotherm of Hg(II) ions corresponds to the Freundlich model, with intensity and volume constants obtained respectively 0.042 and 1.347 L/mg on KM adsorbents, while on KMM adsorbents the intensity and volume constants obtained are 0.291 and 2.079, respectively. L/mg. These results indicate that physical adsorption occurs more dominantly than chemical adsorption. The adsorption of Hg(II) ions was in accordance with the pseudo-first-order adsorption kinetics, with the adsorption capacity and rate constant on the KM adsorbent obtained were 0.0505 mg/g and 0.0072 g/mg, while the adsorption capacity and rate constant for the KMM adsorbent were on KM adsorbents obtained were 0.0848 mg/g and 0.0239 g/mg
Membrane Technology for Water Pollution Control: A Review of Recent Hybrid Mechanism
Full text linkCurrent development of membrane technology for purifying polluted water and wastewater is discussed in this review in accordance with its hybrid application with other types of water treatment methods such as adsorption, advanced oxidation processes (AOPs), and biological activated sludge. This hybrid implementation aims are to lengthen membrane lifespan and elude severe fouling on the surface and pore of the membrane. Membrane material and fabrication technology were concisely included. Two prominent materials to fabricate membrane namely polymeric and ceramic are reviewed well along with the exploration of biopolymers based-materials such as starch and alginate. Several fabrication methods available to be implemented in research or industrial large scale including interfacial polymerization technique, non-solvent induced phase separation, temperature induced phase separation, electrospinning, and sintering are deliberately discussed. The next section includes fouling analysis involving reliable fouling mechanism namely Hermias models to help with the explanation of fouling occurrence during filtration. These models covers four different mechanisms namely complete blocking, standard blocking, intermediate blocking, and cake filtration models. Ultimately, recent research reporting the outcome of the hybridization of membrane and adsorption, biosorption, coagulation-flocculation, AOPs, and biological treatment using microorganism were properly reviewed. Overall, this review considerably promotes the findings of those works which mostly revealed positive outcome of the hybrid membrane system contributing to stronger foundation for future research
Impregnated Zeolite as Catalyst in Esterification Treatment from High Free Fatty Acids Palm Oil Mill Effluent
No full textAlthough Palm Oil Mill Effluent (POME) can be used as a raw material for biodiesel production, the POME contains an excessive amount of Free Fatty Acids (FFA), necessitating a preliminary process and esterification. POME is degummed using phosphate acid and bleached with carbon active. Additionally, this study used KOH-impregnated zeolite to reduce FFA. The purpose of this study is to determine the effect of adding impregnated zeolite on esterification. POME was heated to 600C for 30 minutes, then degumming with 3 % of phosphate acid for 30 minutes, followed by bleaching with carbon active with a comparison ratio of 8:3 at 1000C for 1 hour, and finally, esterification with 3 percent impregnated zeolite from the POME weight at 600C for 4 hours. The analysis was conducted using titration methods to determine the FFA of each esterification. The data will be compared between zeolite and non-zeolite degumming, bleaching, and esterification. The results indicated that the most effective method for reducing FFA was degumming, bleaching, and esterification with zeolite
Steady-State and Dynamic Simulation Study of Reactive Distillation for FFA Esterification in Biodiesel Synthesis
Full text linkReactive distillation (RD) holds promise for process intensification in biodiesel production since it integrates reaction and separation. It simplifies the process and enhances the conversion of the equilibrium limited reactions. To ensure the stability in RD operation, sensitivity study and process control simulation are necessary. In this work, RD was employed for free fatty acid (FFA) esterification of mixed non edible oils in biodiesel synthesis. Non edible oils used were waste cooking oil, crude jatropha oil, and crude nyamplung oil (Calophyllum inophyllum L). Simulation was conducted using ASPEN Plus V8.8. Sensitivity study was carried out to determine the effects of the operating condition alteration. A dynamic simulation was performed as a Proportional-Integral-Derivative (PID) controller tuning. It was revealed that the highest FFA conversion was 85%, achieved at the feed stage of 7, distillate rate of 0.22 kmol/hr, and oil to methanol molar ratio of 1:5. Level, pressure and temperature controls were installed in RD. Then, a dynamic simulation was applied as a PID controller tuning. Three different controller tuning methods, viz. Ziegler-Nichols, Cohen-Coon, and Internal Model Control, were studied. The best PID parameter was obtained by using Cohen-Coon method which provided fastest rise time, lowest settling time and lowest overshoot
Adsorption of Mercury Using Different Types of Activated Bentonite: A Study of Sorption, Kinetics, and Isotherm Models
Full text linkMercury is a hazardous element because of its toxicity and harmful effects on human health. Various traditional and low-cost methods have been developed to remove mercury from wastewater. This study used local raw material as an alternative adsorbent to treat mercury-contaminated wastewater. Activated bentonite was prepared using different chemical activators (H3PO4, HCl, and ZnCl2) in various concentrations. Then, it was dried at 200C for an hour. The materials were characterized by SEM-EDS. Its percent removal and isotherm models were analyzed. In this study, the most effective activator was H3PO4 and the experimental data matched the Freundlich model