11 research outputs found
Adsorpsi Kromium Heksavalen Pada Larutan Aqueous Menggunakan Arang Kayu Teraktivasi Asam: Studi Isotherm Dan Kinetika
Full text linkThis research aims to carry out the adsorption process of hexavalent chromium Cr (VI) utilizing activated charcoal generated from acid-activated wood charcoal using HCl and evaluate the adsorption isotherm and kinetics model. The adsorption procedure was carried out in batches with variations in the Cr (VI) adsorbate concentration, and then the total concentration was finally evaluated using UV-VIS spectrophotometry. The isotherm models employed in this research include the Langmuir, Freundlich, and Temkin isotherm models, while the kinetic models used include pseudo-first order, pseudo-second order, Elovich, and Weber-Morris intraparticle diffusion, which may be estimated using linear regression equations. The findings obtained demonstrate that the adsorption capacity value of acid-activated wood charcoal is 1.1686 mg/g, with the greatest efficiency at 83.9623%. The isotherm model parameters found demonstrate that the Langmuir isotherm model is more acceptable for application in this research with values of R2 = 0.9956, qmax = 1.5126 mg/g, and KL = 0.0783 L/g. The Cr (VI) adsorption kinetics model employing acid-activated wood charcoal follows the pseudo-second-order kinetic equation with values of k2 = 0.0162 g/mg/minute, qe = 0.7927 mg/g, and R2 = 0.9543
Efficiency of FeSO4.7H2O as a Coagulant on Chromium Hexavalent Removal Using Coagulation-Flocculation Process: Optimization Using Response Surface Methodology
Full text linkResponse Surface Methodology-Central Composite Design (RSM-CCD) is widely employed in the process of optimizing the applications of coagulants for wastewater treatment. The experiment aims to evaluate the effect of the FeSO4.7H2O concentration and settling time on removing the chromium hexavalent (Cr (VI)) from wastewater by coagulation-flocculation using RSM-CCD. This experiment was carried out based on the results of the model and optimization using the RSM-CCD to obtain the removal efficiency of Cr (VI) as well as determine the influence of the concentration of FeSO4.7H2O (X1) and settling time (X2). The RSM-CCD experimental design uses a two-factor and two-level design with 13 experimental runs and 5 center points. Inter-variable regression coefficients are also produced with the elimination of Cr (VI). The ANOVA test results showed a fairly significant figure for the assembled model. The model validation results show that the proposed model is compatible with the experimental results. RSM optimization shows optimum conditions based on experimental FeSO4.7H2O coagulant concentration variables and coagulation time at 150 mg/L coagulant concentration and 60 minutes of time, and the prediction results based on RSM-CCD optimization using Design Expert show the most optimum condition at 165,562 mg/L coagulant concentrations and 60,527 minutes of time
Ekstraksi Ubi Jalar Ungu (Ipomoea Batatas L.) Menggunakan Variasi Pelarut Serta Pemanfaatannya sebagai Indikator Asam-Basa
Full text linkPurple sweet potato (ipomoea batatas L.) is one source of carbohydrate. Purple sweet potato contains vitamins and minerals that needed by humans such as vitamin A, vitamin C, calcium, and iron. The sweet potato with purple flesh is widely used as natural dyes which are called anthocyanins. The study aim was to determine a suitable solvent to extract the purple sweet potato. Variation of solvent used namely methanol, methanol acidified with HCl 1% and solvent fractionation (n-hexane, ethyl acetate, and methanol). The extraction phase was divided into two, for flesh and for the skin of the purple sweet potato. The extraction results were then compared with phenolphthalein indicator and a methyl orange on acid-base titration. The results showed that the methanol acidified with HCl 1% provided a more stable color changes in acid-base testing, and the testing of phosphate buffer pH 1-12. Purple sweet potato extracts can be used as an acid-base indicator because it gave similar results with comparative indicators, phenolphthalein, and methyl orange
Comprehensive Study on Cr(VI) Adsorption and Regeneration Behavior of Alkali-Treated Wood Charcoal: Isotherms and Kinetics Models
Full text linkThe present study considers the adsorption and regeneration behavior of alkali-treated wood charcoal (WC-NaOH and WC-KOH) for Cr(VI) removal. Adsorption isotherms (Langmuir, Freundlich, Temkin, and Dubinin-Raduskevich) and kinetics (Pseudo-first-order and Pseudo-second-orderare being investigated utilizing a non-linear method that provides precise parameter prediction and mechanism elucidation. The outcomes suggested that both WC-NaOH and WC-KOH exhibit good Cr(VI) removal efficiency, with the Langmuir model best explaining the adsorption phase, indicating single-layer adsorption. The kinetic study revealed that the Pseudo-second-order model aligns remarkably well with the data, thereby affirming that chemical adsorption is the predominant mechanism in consideration. A comparative analysis revealed that WC-KOH exhibits a higher amount of adsorption than WC-NaOH, attributable to its enhanced larger surface area as well as micro-porous structure.. Regeneration studies showed the possibility of reuse of both adsorbents. It shows the efficiency of alkali-treated wood charcoal for Cr(VI) decontamination and the advantages of non-linear modeling in adsorption experiment
Cr (VI) Removal from Aqueos Solution by Coagulation – Adsorption Integrated System
Full text linkIndustrial wastewater generated by nickel mining has a high content of heavy metals, one of which is Chromium Hexavalent or Cr(VI) metal. Commonly used methods in reducing Cr(VI) metal concentration are coagulation and adsorption. This method is the most economical, simple and highly efficient method. This research uses the coagulation - adsorption integration system method, which is a combination of coagulation and adsorption methods in stages and uses the same wastewater. The purpose of this research is to see the performance of alum, FeSO4 and a combination of alum: FeSO4 as coagulant and fly ash as adsorbent in the removal of Cr(VI) levels in wastewater samples. Also, the efficiency of using the coagulation - adsorption integration system in the removal of heavy metal levels. The adsorption capacity value of this process can also be calculated. The resulting data were then evaluated using a spectrophotometer visible to assess the reduction of Cr(VI) concentration in wastewater. Based on the experiment, alum type coagulant with a waste and coagulant composition ratio of 2:3 and a stirring time of 60 minutes can reduce Cr(VI) levels to 14.18 mg/L from 100 mg/L. The addition of the adsorption process using fly ash helped reduce the concentration of heavy metal Cr(VI) to 12.15 mg/L and the highest efficiency value was 87.9%, and the adsorption capacity value was 0.087 mg/gram
Effectiveness of the Combination of Alum (Al₂(SO₄)₃) and Calcium Hydroxide (Ca(OH)₂) Coagulants in the Removal of Manganese (Mn) Using the Coagulation-Flocculation Process
Full text linkA technique for reducing the contamination of heavy metals in wastewater is the coagulationflocculation method. The approach has various advantages, including a simple process, readilyavailable chemicals, inexpensive equipment costs, and an excellent capacity to remove pollutants. The goal of this research is to see how well Mn-containing wastewater can be reduced using alum and calcium hydroxide as coagulants. The adsorption capacity of the coagulant combination in the floc generation phase of the coagulation-flocculation process can also be calculated. The technique used is coagulation-flocculation, with modifications made to the coagulant content and stirring duration. The data was then evaluated using an Atomic Absorption Spectrophotometer (AAS) to assess the decrease Mn concentration in wastewater. According to the experiments, the combination of alum and calcium hydroxide coagulants with a mass composition ratio of alum:calcium hydroxide (150 mg:50 mg) and a stirring time of 15 minutes has the highest efficiency of 89.35% and is directly proportional to the adsorption capacity value of 446.75mg/gram. 
Effect of Sodium Hydroxide Treatment on Adsorption of Methylene Blue Based on Cellulose Nano Crystals
Full text linkMethylene blue is one of the dye wastes that dissolve in the aquatic environment that cannot be directly degraded by the environment. If the quantity of this waste is large, it will become a compound that is toxic to the aquatic environment. One of the modern methods used to process this dye waste is adsorption. The adsorption method is a method of binding compounds with the help of adsorbents. One of the renewable adsorbent technologies comes from cellulose. Cellulose is often used because it has active groups that are quite effective in binding certain compounds. In this study, cellulose IV was produced, called nano cellulose crystals. Cellulose generally consists of amorphous and crystalline parts. The cellulose produced is hydrolyzed with sulfuric acid to remove the amorphous part so that only crystalline cellulose is obtained, followed by the help of ultrasonic waves to break the size into a nano form which is expected to have a large surface area. As a result of the hydrolysis stage, the nano cellulose crystals produced have sulfate groups that can bind methylene blue which when dissolved in water becomes cationic. This force is called electrostatic force. Some important stages of cellulose nanocrystal production are alkaline treatment, bleaching, hydrolysis, sonication, and freeze-drying. This study focuses on the effect of NaOH concentration used in alkaline treatment. NaOH in this case functions to dissolve impurities such as hemicellulose and lignin in a biomass. Removal of hemicellulose and lignin greatly affects the yield of cellulose produced. Based on the results of the study using 3,4, and 5% NaOH produced cellulose percentages of 38.7121; 39.7949, and 39.9138%, respectively. Cellulose content ultimately affects the number of active groups that bind methylene blue. The adsorption study evidences this obtained the percentage of removal at each concentration of 67.685; 70.837 and 71.823%. Another objective of this study was also to get the constant value of the extraction rate at each NaOH concentration used in the adsorption process. The values obtained were 0.0029; 0.0032 and 0.0039 m/minute at each NaOH concentration used during the alkaline treatment process
Pelatihan Penyusunan Bahan Pembelajaran Berbasis Digital di SMA Negeri 1 Bahodopi
Full text linkPeningkatan aktivitas mengajar secara daring terlebih saat masa darurat penyebaran virus COVID – 19 melanda, membuat tenaga pendidik utamanya seorang guru sangat terbantu apabila memiliki kecakapan dalam penggunaan teknologi, untuk menjangkau para murid yang melaksanakan pembelajaran dari rumah. Oleh karena itu, perlu diadakannya peningkatan komptenesi guru dalam bidang digital education sesuai dengan era saat ini. Berdasarkan kendala yang dimiliki mitra yaitu kurangnya keterampilan SDM (guru) dalam mengolah media pembelajaran berbasis digital untuk meningkatkan minat belajar siswa, agar siswa dapat memahami pembelajaran meskipun menggunakan sistem belajar online utamanya di SMA Negeri 1 Bahodopi. Sesuai pelaksanaannya, Kegiatan peningkatan kompetensi guru di SMA Negeri 1 Bahadopi telah terlaksana dengan baik, namun ada beberapa kendala yang diharapi selama kegiatan ini berlangsung yaitu ketidaksesuaian waktu pelaksanaan, materi yang diberikan belum terperinci, serta keterbatasan perangkat pendukung pembuatan video. Sehingga, para peserta yang terdiri dari guru sekolah dan tim pelaksana menggunakan berbagai peralatan yang ada. Demi mendukung kegiatan tersebut berlangsung dengan baik
Ketalization of Glycerol and Acetone to Solketal: Effect of Temperature, Concentration & Mathematical Model
Full text linkSolketal is a viable method for using glycerol, a by-product of biodiesel production. This study aims to identify the optimal operating parameters for solketal compounds generated from the glycerol ketalization reaction with acetone by using mathematical models that effectively forecast an appropriate framework for this process. This research consists of three critical phases: the ketalization reaction of glycerol with acetone, the characterization of the result solketal products, and the ketalization reaction utilizing the Amberlite IR 120 Na catalyst. The process begins by introducing glycerol and acetone in a mole ratio of 1:3, followed by mechanical Stirring at 500 rpm. The temperature is regulated using a water bath to maintain a constant reaction temperature under specified conditions of 20 °C, 120 °C, 150 °C, and 180 °C, with catalyst masses of 1%, 3%, 5%, and 7%. The mathematical model used is of exponential and polynomial order 2. The findings indicated that the optimal glycerol conversion of 46.01% was attained at 50 °C, using a 5% catalyst concentration throughout a reaction duration of 120 minutes. Second-order polynomial regression is the most appropriate mathematical model to represent this process
Extraction of Natural Colorant from Clitoria ternatea Flowers Using Conventional Solvent Extraction (CSE) and Ultrasound-Assisted Extraction (UAE) Techniques: Kinetic Modeling and Compound Stability
Full text linkThe Clitoria ternatea flowers, a prevalent local commodity in Indonesia, are
extensively found, particularly in the East Java region. One approach to enhance
the utility and economic significance of these flowers involves isolating their
active component, specifically anthocyanin. Anthocyanins have several health
benefits, especially in preventing cardiovascular disease, improving vision, and
being anti-diabetic, anti-inflammatory, and anti-cancer. The isolation methods
used in this research were conventional solvent extraction (CSE) and ultrasonic-
assisted extraction (UEA) methods. The use of UAE has been experimentally
proven to accelerate the extraction rate of bioactive compounds. This dal is caused
by a driving force in the form of energy produced from bubble cavitation resulting
from ultrasonic energy. The specific aim of this study was to compare the
effectiveness of the two methods in anthocyanin isolation. The extraction stages
were carried out at 30, 40, 50, 60, and 70°C operating temperatures, with an S/L
ratio of 1:10, 1:15, 1:20:1:25, and 1:30 with samples conditioned in dry and wet
conditions. The optimal conditions for ultrasound-assisted extraction (UEA)
involve dry samples with a S/L ratio of 1:30 at a temperature of 70°C with the
resulting final concentration of 16.5234 g/L. This configuration ensures an
efficient extraction process, completed in less than 30 minutes, thereby
preventing the degradation of anthocyanins. Analysis indicates that the
extraction process adheres to a second-order kinetic model with a constant (k) of
0.1039. Stability testing revealed that the first–order kinetic model accurately
represents the impact of temperature on anthocyanin degradation
