Jurnal Rekayasa Kimia & Lingkungan
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Preparation and Characterization of Interfacially Polymerized Polyamide Membrane for Dye Removal
Full text linkInterfacial polymerization of polyamide was conducted using hydrophobic and hydrophilic membrane support. The effects of monomer concentration were investigated, and the resulting thin-film composite membranes were tested for their performance in dye removal using different flow configurations. The results showed that a dense polyamide layer was successfully formed on the hydrophilic support, while a polyamide layer with a very loose structure was formed on the hydrophobic support. The polyamide layer became smoother and more hydrophilic as the concentration of trimesoyl chloride was increased, leading to increased permeate flux and reduced dye rejection. The highest sunset yellow rejection of 45.7% with a permeate flux of 4.9 L/m2.h was obtained when the polyamide layer was formed from trimesoyl chloride concentration of 0.05 w/v% (a high amine to acid chloride monomer ratio of 20) and the filtration was in cross-flow configuration
Physical Characteristics of Briquettes Made of Oil Palm Empty Fruit Bunches (EFB) Using Brown Algae Adhesive
Full text linkThe charcoal produced from oil palm empty fruit bunches pyrolysis can be utilised as environmentally friendly alternative fuel briquettes. This research studied the physical characteristics of EFB briquettes using brown algae as an adhesive. The effect of the concentration of brown algae adhesive on briquette quality was investigated. The briquettes were prepared from EFB charcoal by adding adhesive at various concentrations of 2.5%, 5%, 7.5% and 10% (w/w). Subsequently, proximate analysis was performed on EFB and brown algae. The best-quality briquettes were obtained by adding brown algae adhesive at 2.5% concentrate, which resulted in a calorific value of 21,405 J/g. Other characteristics, such as moisture content, ash content, volatile matter and fixed carbon, were found to be 7.4%, 4.9%, 79% and 8.7%, respectively. Thermal characteristics, such as density, flash point and burning time, were found at 0.96 g/cm3, 5.1 seconds and 300 minutes, respectively
Soil Fungal Community Responses to the Silver Nanoparticles Contamination as Assessed by Illumina Next Generation Sequencing (NGS)
Full text linkThe increasing use of silver nanoparticles (AgNPs) due to its excellent antimicrobial activity in commercial products prompting concerns about their fate in the environment. The toxicity of AgNPs is mainly the result of Ag+ ions. In this study, soil was experimentally contaminated with 100 mg kg-1 of AgNO3 to investigate its effect on fungal soil community. Deoxyribonucleic acid (DNA) from the soil was extracted at the 6th, 12th, and 24th month of observation and assessed by Illumina Next Generation Sequencing (NGS). The results show that, the pollutant change fungal community in soil. After 12 months incubated the number of fungal species in the soil reduced significantly and 40% of the community was dominated by one species
Preparation of Hydroxyapatite Scaffold using Luffa Cylindrica Sponge as Template
Full text linkHydroxyapatite (HA) scaffold has been widely applied in the biomedical field especially for bone implants. The purpose of this research is to determine the influence of dispersant addition and stirring time on HA scaffold which formed using gambas sponges as a template. HA slurry was made by mixing 10 grams of HA, 12 grams of aquadest, 0,2; 0,25; 0,3 grams of Darvan 821A and 1 gram of sago. The slurry was impregnated into Luffa cylindrica sponges. The sample then dried at 110oC for 3 hours. The green bodies were burned at 600oC for 1 hour and followed by sintering at 1250oC for 1 hour. The results showed that the addition of dispersant and increasing of stirring time lead to smaller porosity and shrinkage. In addition 0,2; 0,25; and 0,3 grams dispersant, the resulting porosity in the range of 63,85-70,78%; 58,74-70,35%; and 53,42-69,66%. Shrinkage 39,43-53,71%; 27,75-50,68%; and 13,61-41,25%. Compressive strength 0,61-1,05 MPa; 2,88-3,81MPa; and 0,52-2,96 MPa. The macroporous and microporous average pore sized was 50 m dan 5 m
Alteration of Biodiesel Properties and Automotive Diesel Engine Performance due to Temperature Variation of the Transesterification Process
Full text linkThis study aimed to examine the effects of transesterification reaction temperature on the biodiesel properties and diesel engine performance. Biodiesel properties evaluated in this work included viscosity, density, and methyl ester content. Meanwhile, the diesel engine performance testing comprised the examination of the engines torque and power. The research was conducted in several stages, viz. producing biodiesel from fresh cooking oil with variations in transesterification temperature of 45, 55, and 65; testing the characteristics of biodiesel produced; blending biodiesel with petroleum diesel to result in B30 biodiesel fuel; and testing biodiesel fuel (B30) in diesel-engined vehicles. It was revealed that the higher transesterification temperature led to the lower biodiesel viscosity, the decreasing value of biodiesel density values, and the higher methyl ester content. Furthermore, it was also demonstrated that increase of the transesterification temperature resulted in the higher value of torque and power generated. However, compared to the petroleum diesel fuel (B0), biodiesel fuel (B30) exhibited the lower values of the engines torque and power. The highest average values of torque and power of B30 fueled diesel-engine were 108.11 Nm and 43.51 kW, respectively, provided by the biodiesel produced at the transesterification reaction temperature of 65.of 65
Characterization of Activated Coconut Shell Charcoal as a Zinc Absorbent for Used Oil Lubricant
Full text linkLubricating oil is classified as B3 waste (hazardous and toxic waste). In the lubricating oil consists of zinc waste which is very dangeraous for healt and environment. So that to handle lubricating oil is used the adsorption method using coconut shell as adsorbent. This study aims to determine the efficiency of zinc adsorption on lubricating oil with stirring speed, percent solvent, mesh size, and mass of adsorbent variation; to learn the equibilium equation of adsorpsion of Zn metal ion on the activated carbon of coconut shell charcoal using Freundlich and Langmuir equilibirium; and to calculate adsorbtion kinetic constanta using the pseudo first model or pseudo second order kinetics approach. Coconut shells was heated at a temperature of 300C for 1 hour for the driving process . Furthermore, charcoal was soaked in 25% HCl for 18 hours. After being neutralized to pH 7, the charcoal was activated for 3 hours at a temperature of 500C and stored in a closed place. Coconut shell adsorbent and H2SO4 solvent were put into a beaker glass containing 400 ml of lubricating oil and stirred for 2 hours, every 30 minutes intervals were taken 50 ml to destruction for 2 hours with 68% HNO3. The zinc concentration before and after adsorption were measured using AAS. This study uses the Langmuir isotherm and Freundlich Isotherm models. The greatest efficiency of zinc adsorption with solvent percent variation 0.5% is 95.0567% and 99.9375% in adsorbent mass variation of 10 gram
Degradation of Methyl Violet Using TiO2-Bayah Natural Zeolite Photocatalyst
Full text linkDegradation of methyl violet using photocatalysis method has been investigated. In this study TiO2 was superimposed on the surface of the Bayah natural zeolite with two solvents, ethanol and distilled water. The activation of the Bayah natural zeolite using HCl. In this study the effect of zeolite size (60.80 and 100 mesh), the composition of TiO2-Zeolite (0.2, 0.4 and 0.6) and intensity of photon energy on the degradation of methyl violet has been evaluated. The samples were were characterized by means X-ray powder diffractometer (XRD). The specific surface area of each sample was determined by the BET nitrogen gas adsorption/desorption method. The measurement of methyl violet concentration using UV Vis spectrophotometry. The results showed the optimum composition of TiO2 in zeolite was 4 grams with a solvent of distilled water. By Using this sample could reduce methyl violet by 94,5% for 4 hours with UV light intensity of 1340 W /cm2
Electroanalytical Performance of Graphene Paste Electrode Modified Al(III)-TiO2 Nanocomposites in Fipronil Solution
Full text linkThe new composite material Al(III)-TiO2 has been synthesized and applied as a modifier of graphene paste electrode for the determination of fipronil pesticide by cyclic voltammetry. The methods were to synthesis of Aluminum-Titanium dioxide (AT), preparation of graphene paste electrode with mass varied Al(III)-TiO2 (GAT) (0.05 g, 0.1 g, 0.2 g), and fipronil electroanalytic respons. Addition of Al(III)-TiO2 to the graphene paste electrode shows redox properties which are well characterized by a fast electron transfer process. Based on the results of measurements in a solution containing fipronil, it is known that fipronil is oxidized at a potential value of 0.26 V. Furthermore, the fipronil oxidation process on the GAT surface is influenced by diffusion control, this is powered by R2 value 0.91 when plotted between peak oxidation currents (Ipa) vs. root scan rate. Other results show that measurement linearity is in the range 0.01 to 0.09 g/L with a limit of detection (LOD) value of 0.0164 g/L. Moreover, GAT shows good stability in the determination of fipronil with% RSD equal to 5%
The Improvement of Hydrophilic Property of Polyethersulfone Membrane with Chitosan as Additive
Full text linkMembrane technology has been implemented broadly for clean water treatment. To produce a better membrane, modification is carried out by adding chitosan into a polymer solution. Materials used in this research are polyethersulfone (PES) 18%, the n-methyl pyrrolidone solvent modified with a chitosan solution (at 0.2 1 wt%) as an additive, and deionized water as a non-solvent. The membrane synthesis is carried out with the non-solvent induced phase separation method of blending the polymer. Membrane characterization includes functional group analysis, morphological structure, and water contact angle. Membrane performance is monitored at the filtration process, resulting in the permeability coefficient, and for the rejection of a contaminant (humic acid) with dead-end filtration. Research results show that the modified membrane characterization has an asymmetric morphological structure with a thinner top layer, and the membrane sublayer has a finger-like macrovoid structure with a larger size as compared to the original PES membrane (without the chitosan solution addition). The chitosan additive into the PES membrane improves the membranes hydrophilic property. The highest value of the permeability coefficient is achieved with a 1% chitosan addition, which provides a permeability coefficient value of 10.524 L/m2.h.bar and a rejection coefficient of 70.3%
Preparation and Characterization of Activated Carbon Made from Robusta Coffee Skin (Coffea Canephora)
Full text linkIndonesia is one of the coffee-producing countries where production tends to increase from year to year. Currently, residuals from coffee-fruit processing such as coffee-skin and husks are thrown away without any use and this biomass residual contains several toxic chemicals such as alkaloids, tannins, and polyphenols. One of potential uses of coffee-industry by-product is to make activated carbon (ACs), which is made through a carbonation process and followed by an activation process. In this study, chemical activation was carried out using chemical activators ZnCl2 and NaOH. The purpose of this study is to prepare and investigate the characteristics of chemically activated coffee skin bio-char focusing on the surface properties and iodine adsorption capacity. Prior to carbon activation, a purpose built pilot-scale reactor was fabricated and tested at temperatures of 400 C and 500 C. The difference in carbonation temperature and variations in activator concentration alter the absorption properties. The results showed that the coffee-skin pyrolyzed at 500 C and activated by 2% NaOH solution exhibits the highest absorption value of 720.2 mg/g. Lower absorption values were observed in any ZnCl2 activator samples. SEM-EDS analysis result suggests significant changes in composition of the ACs before and after activation. Most of impurities are gone during activation and washing. The value of C atoms increases and the pores structure of the activated carbon are expanding showing suitable properties for adsorbent