Jurnal Rekayasa Kimia & Lingkungan
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Advanced Applications of Pozzolan-Derived Silica: Hydrophobic Agent Synthesis
Full text linkThe Sumatera Barat province of Indonesia, particularly Padang Pariaman Regency, is rich in pozzolan, a natural resource characterized by high silica (SiO) and alumina (AlO) content. Despite its abundance, pozzolan remains underutilized, primarily used in conventional applications such as cement substitutes and brick production. This study investigates the extraction, purification, and application of pozzolan-derived silica for advanced industrial uses, focusing on synthesising hydrophobic materials. Silica was extracted from pozzolan using alkali and acid treatments, achieving a high-purity cristobalite phase with 93.86% SiO content based on the X-ray diffraction (XRD) and X-ray fluorescence) XRF analysis. The cristobalite phase was combined with polydimethylsiloxane (PDMS) to develop a hydrophobic agent. Hydrophobic performance was evaluated using water contact angle (WCA) measurements, with two coating methodsswab coating and dip-coatingemployed to test the materials. Results revealed that the cristobalite phase achieved the highest hydrophobicity when applied via dip-coating, reaching a WCA 114. Fourier Transform Infrared (FT-IR) analysed the characteristics of a hydrophobic compound. Furthermore, varying PDMS concentrations influenced hydrophobic performance, with 0.4 grams of PDMS yielding the optimal WCA of 105.31 before diminishing returns were observed at higher concentrations due to aggregation effects. This research demonstrates the viability of pozzolan-derived silica as a sustainable and cost-effective raw material for hydrophobic agent synthesis. The findings highlight its potential applications in advanced industries, including water-repellent coatings, glass, ceramics, and catalysts. By advancing the utilization of natural pozzolan resources, this study contributes to sustainable material development and aligns with global efforts to enhance resource efficiency and innovation
Green Synthesis of Silver Nanoparticles Using Caulerpa racemosa Extract as Bioreductor: Characterization and Antibacterial Activity
Full text linkSilver nanoparticles (AgNPs) have attracted much attention due to their broad antimicrobial properties and have found many applications in various fields. In the current study, AgNPs were synthesized using an environmentally friendly method by utilizing Caulerpa racemosa extract as a bioreduction agent. This study aims to investigate the formation of AgNPs mediated by Caulerpa racemosa extract and to observe their antimicrobial capability. The concentration of silver nitrate (AgNO3) was varied to investigate its influence on the shape, size, and uniformity of the silver particles formed. The Fourier Transform Infra-red (FT-IR) test results revealed that Caulerpa racemosa extract has an (-OH) functional group that reduces Ag+ ions to Ag0, making it effective as a bioreductor for AgNPs synthesis. The shape and size of AgNPs were examined using Scanning Electron Microscope (SEM), and the results confirmed that increasing AgNO concentration from 5 to 20 mM produced larger and agglomerated particles. Additionally, AgNPs inhibitory effect on the growth of pathogenic Escherechia coli (gram-negative bacteria) was evaluated using the well diffusion method. The findings showed that AgNPs improved the antibacterial properties when incorporated into chitosan-based film solution. This indicates that AgNPs exhibit strong antibacterial activity against gram-negative bacteria and hold promises for use in bio-related applications, including food packaging and biomedical use
Bioactive Potential and Antioxidant Activity of Blood Clam (Tegillarca granosa L.) Protein for Functional Food Applications
Full text linkThis study investigates the antioxidant potential and protein content of the blood clam (Tegillarca granosa L.), a marine species rich in bioactive compounds that could serve as a functional food source. Antioxidants play a crucial role in combating free radicals, which are linked to various degenerative diseases. This research aims to quantify the protein content and evaluate the antioxidant activity of blood clam extracts to assess their potential for functional food applications. The study utilized the Lowry method to measure protein content and the DPPH assay to assess antioxidant activity. Blood clam samples were collected from the coastal region of Pangkep, South Sulawesi. Protein levels were determined using UV-Vis spectrophotometry, while antioxidant activity was quantified by IC50 values. Results indicate that blood clams contain 21.75% protein, with an IC50 antioxidant value of 17.935 0.360 g/mL, which, while lower than ascorbic acid (IC50 = 2.34 g/mL), demonstrates substantial antioxidant activity. This studys unique contribution to the functional food field lies in identifying blood clams as a promising source of both protein and antioxidants, with potential health benefits related to oxidative stress prevention. The practical implications highlight blood clam's suitability as a natural functional food ingredient aimed at supporting overall health
Techno-economic Review of Isolation of Eugenol from Clove Oil with Batch Distillation
Full text linkAll parts of the clove plant (Syzygium aromaticum L.), including roots, stems, leaves and flowers, can be processed into clove oil. One of the important compounds in clove oil is Eugenol. Pharmaceutical grade eugenol has a very high selling value, however conventional refining without a purification process only produces clove oil with a eugenol content of 78-80%. In this research, the purification of eugenol from clove oil refined by clove farmers was carried out by comparing two methods, namely the reactive extraction process and batch distillation. Analysis of the final products from both processes was carried out by GC-MS. The eugenol isolation process using a reactive extraction method with various variations in NaOH purity obtained optimum results at 2 N NaOH levels where clove oil was produced with a eugenol content of 75.33% with a product recovery of 40%. Meanwhile, eugenol was isolated using batch distillation with constant reflux and atmospheric pressure to obtain pure clove oil with a eugenol content of 97.02% with a product recovery of 28.25%
Synthesis of Struvite Fertilizer (MgNH4PO4.6H2O) from Cow Urine and Bittern by Precipitation Technique
Full text linkThe need for fertilizers has significantly increased due to the expanding global population and the mounting pressure on agricultural systems to increase food production. Fertilizers are essential in upgrading soil fertility and increasing crop productivity, making them indispensable in contemporary agriculture. Extensive usage of chemical fertilizers has led to environmental issues such as soil deterioration, water contamination, and the exhaustion of non-renewable resources like phosphate rock. Phosphorus, one of the essential macronutrients for plants, is a critical component of commercial fertilizers. Struvite, with its high phosphate content, presents a viable alternative to conventional fertilizers. Struvite (MgNH4PO46H2O) is a crystalline compound comprising magnesium, ammonium, and phosphate. Cow urine, which contains nitrogen, phosphate, and potassium, can serve as a nutrient source for plants. In the context of fertilizer production, bittern serves as a source of magnesium. This study investigated the production of struvite from cow urine and bittern using a precipitation technique. The study aimed to determine the optimal conditions for maximizing struvite production, focusing on the ratio of cow urine to bittern and the storage duration of cow urine. The research involved the preparation and characterization of raw materials, struvite synthesis, and the analysis of struvite characteristics. The optimal conditions were found to be a molar ratio of cow urine to bittern of 1:1 and a cow urine storage time of one week. UV-VIS spectrophotometry was utilized to analyze phosphate and ammonia contents, yielding optimal values of 72.417 mg/kg and 0.715 mg/kg, respectively. XRF analysis indicated a magnesium content of 26.000 mg/kg. SEM and XRD analyses revealed that the morphology of the struvite was orthorhombic at the optimum conditions. FTIR analysis was used to identify N-H, P-O, and water vibrations
Batch Adsorption of Tannins from Stevia Leaf Extract using Activated Carbon: An Investigation into Adsorption Isotherms and Adsorption Energy
Full text linkStevia leaf extract (Stevia rebaudiana Bertoni) could have been utilized as an alternative natural sweetener because it possessed a sweetness level 300 times that of sucrose sugar. However, stevia leaf extract still contained a bitter taste attributed to the presence of tannins. The method that can be used to reduce tannin content is batch adsorption using activated carbon. This study aimed to investigate the batch adsorption process for the tannin content of stevia leaf extract using activated carbon with variable adsorption times ranging from 5 to 180 minutes, which included the appropriate adsorption isotherm model and adsorption energy. Stevia leaves were extracted through maceration with 70% ethanol. The results of the stevia leaf extract were adsorbed in batches using activated carbon treated with 1M NaOH. The analysis was carried out by testing the tannin content (mg/g TAE) using a UV-Vis spectrophotometer at a wavelength of 735 nm and calculating the adsorption isotherm and adsorption energy. The results showed that the tannin content before adsorption was 0.910 mg/g TAE, and the lowest tannin content was 0.040 mg/g TAE at 100 minutes. The tannin content decreased between 590 minutes, remained constant, reached equilibrium at 95120 minutes, and increased again at 125180 minutes. The suitable adsorption isotherm model was the Freundlich isotherm with a value of R2 = 0.9998; KF = 25.293 [(mg/g)(L/mg)1/nf], and adsorption energy = -8.03 kJ/mol. The adsorption that occurred was classified as physical adsorption
Synthesis and Characterization of Calcium Phosphate Using Two Stages of Process
Full text linkCalcium phosphate, a naturally occurring biomaterial found in human and animal bones and teeth, possesses desirable properties such as strength, biocompatibility, and the ability to stimulate tissue growth. This study investigates the synthesis of calcium phosphate through a precipitation method without calcination. The process involves dissolving raw materials in phosphoric acid, followed by precipitation using KOH as the precipitating agent. The resulting precipitate was then calcined for 3 hours. The calcium phosphate product was characterized using XRF, XRD, and SEM-EDX techniques. The results indicate a Ca-P molar ratio ranging from 1.855 to 2.302, with the predominant phase identified as -calcium pyrophosphate. SEM analysis reveals a plate-like morphology with agglomerated particles ranging in size from 888 nm to 7.79 m. The synthesized calcium phosphate holds potential for various biomedical applications due to its unique properties and composition
Kinetic Model of Chemical Organic Matter Removal in Facultative Pond Set A in Domestic Wastewater Treatment Plant (WWTP) Bojongsoang, West Java
Full text linkKinetic models are widely used to predict the performance of biological treatment systems. The facultative ponds are applied as a biological treatment for domestic wastewater in the Wastewater Treatment Plant (WWTP) located in Bojongsoang, Bandung Regency, West Java. This study aims to evaluate the suitability of several kinetic models for the chemical oxygen demand (COD) removal process that occurs in facultative ponds in WWTP Bojongsoang. The best kinetic model will provide a more accurate predictions of COD effluent concentrations in facultative ponds. Data series of COD influent and effluent concentration were collected from field data of water quality monitoring monthly from years 2019 to 2022. The kinetic models used in this study were the first-order kinetic model combined plug flow pattern, the first-order kinetic model with continuous stirred tanked reactor flow pattern, the plug flow k-C* model, and the Stover-Kincannon model. Model accuracy was evaluated using statistical methods by calculating the mean average percentage error (MAPE) to compare model data with measured observation data. The COD effluent prediction showed that the Plug Flow k-C* model had the smallest MAPE for both facultative ponds, namely 28.3% for facultative pond 1A and 30.2% for facultative pond 2A. Kinetic rate values for both facultative ponds using plug flow k-C* model respectively, 0.1818 m/day for F1A and 0.1750 m/day for F2A
Vanillin from food flavoring products as a cheaper alternative hydrophilic agent for modifying PVDF membranes in the treatment of organic compounds in water
Full text linkMembrane fouling is an unavoidable challenge in ultrafiltration, resulting in reduced flux and increased operating costs. Surface modification of polyvinylidene fluoride (PVDF) membranes can improve hydrophilicity and extend membrane lifetime. This study investigates vanillin from food flavoring product (VFFP) as a hydrophilic additive for PVDF membranes to enhance antifouling properties. The immersion precipitation phase inversion method was used to prepare membranes with 0-3% (w/w) vanillin. The results of FTIR analysis of VFFP show similarity in absorption peaks with commercial vanillin. The addition of 3% w/w VFFP to PVDF membrane can improve the hydrophilicity by reducing the contact angle from 86 to 76.26. Membrane performance showed good results with modified membranes having higher water fluxes than unmodified membranes. In addition, higher flux recovery ratio (FRR) values indicated better antifouling properties.The addition of vanillin significantly improved the performance of PVDF membranes, confirming its use as a hydrophilic additive
Innovations in the Cement Industry: Advancing Towards Sustainable Concrete Production
Full text linkSlag, an artificial pozzolan derived from the by-product of metal ore smelting, exhibits notable richness in active silica and alumina. This investigation scrutinizes the influence of slag as a clinker substitute on cement quality. The study explores the composition range of slag from 15.69% to 20.39% of the total cement mass. Other constituent materials, including gypsum (2.07%), limestone (17.24-22.54%), and clinker (55-65%), are compared with commercial cement available in the market, featuring 73.09% clinker, 2.07% gypsum, 11.89% limestone, and 12.95% trass. The study employs rigorous physical tests, encompassing Blaine, residue at 45 m (325 mesh), flowability, setting time, and compressive strength assessments at 1, 3, 7, and 28 days. The Blaine testing, the residue at 45 m, and other tests were conducted meticulously to ensure the accuracy and reliability of the results. Blaine testing measured specific surface area, residue at 45 m assessed fineness, flowability evaluated paste workability, setting time determined paste stiffness, and compressive strength assessed material durability. All tests followed ASTM standards, providing reliable insights into cement performance. Compared to the commercial sample, there is a decrease in compressive strength in all results with an increase in the amount of slag. This condition is because components such as tricalcium silicate (C3S) and dicalcium silicate (C2S), which play a crucial role in producing hydration strength, decrease with the reduction of clinker. However, the compressive strength specified by ASTM C 109/109M-01 280 kg/m2 standard is still exceeded. Optimal results are obtained with a slag substitution of 16.64%, resulting in compressive strength of 305 kg/m2 at 28 days. This investigation highlights slag as a promising substitute for clinker in cement production due to its high silica content. Slag offers several advantages, including enhanced sustainability by reducing environmental impact and lowering production costs. Its utilization diversifies raw material sources, promoting industry resilience