Jurnal Riset Kimia
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Study of Aluminum-Copper Electrodes for Chromium and Chemical Oxygen Demand Removal from Tannery Wastewater by Electrocoagulation
Get PDFThis study investigates the efficacy of the electrocoagulation (EC) process using aluminum (Al) anodes and cathodes for the treatment of leather tanning wastewater. Initial characterization revealed a chemical oxygen demand (COD) of 901.96 mg/L and total chromium content of 38.741 mg/L, where it exceeds the discharge limit permitted by the Minister of Environment Regulation No. 5/2014, the permissible limit for COD in industrial wastewater is 110 mg/L, and for total chromium, it is 0.6 mg/L. The EC process, conducted under varying conditions of electrolysis time (10, 20, and 30 minutes), potential (2.0, 3.0, 3.5, and 4.5 V), and current intensity (1.0, 2.0, and 3.0 A), demonstrated substantial reductions in both COD and chromium levels. The lowest COD value achieved was 28.05 mg/L at 3A, 4.5 V, and 30 minutes, representing a reduction of 52.09% to 74.50%. Total chromium content was reduced to as low as 0.013 mg/L, indicating a reduction of 90.45% to 97.83%. pH levels were monitored, revealing an increase due to OH- ion formation, with final pH values ranging from 6.38 to 8.34. XRF analysis of the commercial Al anode indicated a composition of 98.1% Al, 0.615% Fe, 0.522% Si, and 0.163% Zn. The findings underscore the effectiveness of the EC process in reducing COD and chromium content in leather tanning wastewater, meeting and exceeding regulatory standards
Selectivity of Molecularly Imprinted Polymer-based Chitosan Membrane for Caffeine Separation by Filtration
Get PDFCaffeine is a chemical compound that can be isolated from coffee beans. The isolation and purification of caffeine compounds have been successfully carried out using a filtration method using chitosan biomaterial synthesized by molecularly imprinted polymer (MIP). Chitosan as a functional polymer is dissolved in acetic acid (2% v/v) with stirring at 60°C overnight until a clear and homogeneous solution is formed. Furthermore, caffeine as a template molecule is added to the polymer solution and stirred for 60 minutes. The polymer solution is poured into a petri dish until evenly distributed and dried in an oven at 60°C for 12 hours. The dried polymer solution is then soaked in sodium tripolyphosphate as a crosslinking solution and dried again in the oven until the membrane sheet separates from the petri dish. The membrane sheet is then washed using distilled water until the pH is neutral and continued washing with chloroform to remove caffeine from the membrane pores to form an MIP membrane. The formed MIP membrane is characterized using FTIR and SEM. The MIP membrane was then cut into a circle, inserted into an empty syringe, and used to filter samples containing caffeine. The filtration results were analyzed using a UV-Vis spectrophotometer which showed that caffeine filtered with the MIP membrane contained less interference than caffeine filtered with a non-imprinted polymer membrane (NIP). Quantitative analysis was also carried out using the spiked sample method to determine the recovery value of the filtration results. From this study, the percentage recovery value (% recovery) was obtained at 96.16 - 103.80%
Development of The Scanometric Method for Caffeine Determination in Pharmaceutical Preparations
Get PDFThe caffeine assay can be developed by using sensitive reagents for caffeine detection, such as sodium periodate (NaIO4), acetic acid (CH3COOH), and 3-methyl-2-benzothiazolinone hydrazone (MBTH) inside 96-microwell plate. The addition of caffeine solution could change the color of the reagent from white to deep blue which can be then scanned and quantified by a flatbed scanner and the color image analysis program, known as the scanometric method. Analytical characterization such as linearity, LOD, LOQ, precision, accuracy, and stability of the developed method was established by using caffeine standard. The result of caffeine analysis using the developed method agreed with that of the spectrophotometric method, suggesting that the developed method can be used as an alternative method for caffeine assay in pharmaceutical preparations
Determination of Apoptosis Level of Hela Cells Treated with Disobinol Compound from Chisocheton Macrophyllus Plant
Get PDFDisobinol is a limonoid compound from the seeds of the Chisocheton macrophyllus plant that has been reported to have anticancer activity against cervical cancer cell lines. Cervical cancer is a type of cancer caused by infection with Human papillomavirus (HPV) types 16 and 18, leading to the transformation of normal cervical epithelial cells into cancerous cells. Previous studies show that Disobinol has a cytotoxic effect on HeLa cells with the IC50 value 52,92 μg/mL (24 hours’ incubation). This study aims to determine the level of apoptosis in HeLa cells treated with Disobinol and observe the DNA fragmentation in HeLa cells undergoing apoptosis. The HeLa cells were treated with Disobinol at concentrations of 26,5 μg/mL (1/2 IC50), 52,3 μg/mL (IC50), and 104,6 μg/mL (2x IC50) and incubated for 24 hours. The level of apoptosis was analyzed by using flow cytometry, and the DNA fragmentation pattern was analyzed by agarose gel electrophoresis. The results showed that Disobinol induces early apoptosis in HeLa cells, although the difference in the percentage of cell death is not very significant, which were 37.05%, 37.7%, and 41.60%, respectively. The DNA fragmentation pattern in HeLa cells treated with various concentrations of Disobinol was also observed on agarose gel. Therefore, Disobinol has the potential to be used as a chemotherapeutic drug or as a lead compound for the treatment of cervical cancer
Synthesis of Pyridazinone Derivatives Substituted with Methoxy with Phenyl Hydrazine and In Silico Test of Anticancer Activity
Get PDFThe synthesis of pyridazinone derivatives has gained increasing attention due to their diverse biological activities, particularly as anticancer agents. In this study, novel pyridazinone derivatives substituted with methoxy groups and phenyl hydrazine were synthesized through a multi-step reaction pathway, starting from methoxyacetophenone and glyoxylic acid, followed by cyclization and substitution reactions to yield the target compound 7-(2-methoxyphenyl)-2H-pyridazino[6,1-c][1,2,4]triazine-3(4H)-one. The synthesized compounds were characterized by melting point, TLC, HPLC, UV-Vis, FTIR, NMR, and MS analyses, confirming the expected structures. In silico evaluation was performed using molecular docking against estrogen receptor α (ERα) kinase domain (PDB ID: 1T46), a key protein in breast cancer progression. The docking results showed that the synthesized compounds exhibited strong binding affinities, with compound 8 displaying a binding free energy of –9.1971 kcal/mol and stable interactions with residues Cys673, Leu799, and Phe811. These values were superior compared to the natural ligand and comparable to the reference drug doxorubicin, indicating significant anticancer potential. The results suggest that structural modification of pyridazinone with methoxy and phenyl hydrazine substituents enhances its cytotoxic activity, making it a promising candidate for further development as an anticancer agent
Structure, Morphology, Optical, Magnetic and Dielectric Properties of Ni1-xCdxFe2O4 Material Synthesized by Autocombustion Method
Get PDFMaterials with nanoscale dimensions have recently attracted attention due to their outstanding electrical, magnetic, and dielectric capabilities. Electromagnetic materials, known as spinel ferrite MFe2O4 (M = divalent ion), are essential in advanced technology. Cadmium-substituted ferrite spinel with composition Ni1-xCdxFe2O4 (x = 0, 0.1, 0.15, and 0.2) was synthesized by the autocombustion method using citric acid as a fuel agent. X-Ray Diffraction (XRD) confirms that the spinel structure is present in the prepared nanocrystalline ferrites. Fourier Transformed Infrared Spectroscopy (FTIR) spectra showed intensive absorption bands in the 400-600 cm-¹ range corresponding to tetrahedral and octahedral sites. The absorption spectrum of FTIR shifts towards lower wave numbers as the Cd2+ ion concentration increases. Cd2+ ions doping is important for crystal growth, as evidenced by Scanning Electron Microscopy (SEM) images. The band gap energy values of Ni1-xCdxFe2O4 samples are 1.53 eV, 1.46 eV, 1 43eV, 1.42 eV for x=0-0.2, which indicates the samples absorb in visible light. Analysis of magnetic properties with Vibrating Sample Magnetometer (VSM) shows a small hysteresis loop, so Ni1-xCdxFe2O4 is a soft magnetic material. The dielectric constant increases as the Cd2+ ion concentration increases. The characterization outcomes recommend that the compounds can be used for several applications such as memory, and energy storage devices
Corrosion Analysis on Stainless Steel (SS304) Using A Coating Method Based On Silica from Natural Sand of Hukurila Village
Get PDFCorrosion analysis was performed on stainless steel (SS304) coated with silica extracted from silica sand in Hukurila Village using the coprecipitation method. The XRF results showed an increase in silica content from 58.118% to 81.247%, indicating high purity. XRD testing revealed that the silica was amorphous, while SEM analysis showed that the silica powder particles were irregular in shape and size, and tended to undergo agglomeration. The silica was then applied as a coating on SS304 using Nippon Paint with silica-to-paint weight ratios of 95:5, 90:10, and 80:20. The samples were tested in a 3.5% NaCl solution for 7 days using polarization methods on a potentiostat to measure corrosion resistance. The results showed that the 80:20 weight ratio provided the highest improvement in corrosion resistance. This enhancement is attributed to the more compact and uniform coating structure formed at higher silica loading, which effectively minimizes micro-pores, strengthens the barrier effect, and suppresses localized pitting corrosion
Optimization of Tannic Acid Polymerization to Improve the Efficiency of Dye-Sensitized Solar Cells: Effect of Temperature and Monomer Concentration
Get PDFThis study investigates the effects of temperature and monomer concentration on tannic acid polymerization to enhance dye-sensitized solar cell (DSSC) efficiency. Tannic acid was polymerized using Trimethylolpropane Triglycidyl Ether (TMPGDE) as a crosslinker, with monomer concentrations of 2, 2.5, and 3 grams and temperatures ranging from 30°C to 110°C. UV-Vis analysis revealed a bathochromic shift in poly-tannic acid, indicating increased light absorption in the 200-800 nm range. FTIR confirmed the formation of new ether groups, signifying successful polymerization. The highest DSSC efficiency (8.984%) was achieved with 2.5 grams of monomer at 50°C, significantly outperforming unpolymerized tannic acid (1.35%). The optimal poly-tannic acid has an average molecular weight of 32,610.1568 and a polymerization degree of 19.182. This research demonstrates the potential of tannic acid polymerization for improving DSSC performance, paving the way for more efficient and cost-effective organic solar cells
Development and Characterization of Recycled Polypropylene/Teak Wood Dust Composites for Sustainable Applications in the Automotive Components Industry: Thermal and Mechanical Properties
Get PDFUtilizing recycled plastics is a crucial strategy for reducing waste and developing sustainable materials. Most of the recycled polypropylene (PP) in the industry is from reprocessed scrap. In contrast, this study explores a more challenging feedstock: post-consumer water cups collected by waste pickers, representing an environmentally impactful pathway. The recycled PP was combined with teak wood dust, an abundant lignocellulosic byproduct, antioxidant additives (Irganox 1010, Irgafos 168), and polypropylene-grafted-maleic anhydride (PPgMA) as a coupling agent to produce composites for the potential automotive component industry. Teak wood dust was added at 0–20 wt% to evaluate its influence on the thermal and mechanical performances. Fourier-transform infrared (FTIR) analysis confirmed that recycled PP maintained the functional groups similar to virgin PP, supporting its recyclability. Differential scanning calorimetry (DSC) showed decreasing enthalpy of fusion (101 to 91 J/g) and crystallinity (48% to 44%), indicating the disruption of crystalline packing by teak wood dust filler. The composites exhibited improved flexural strength and modulus with increasing filler content, attaining maximum values of 56.2 MPa and 2,132.9 MPa at 20 wt%. However, Izod impact strength decreased from 564 J/m (0 wt%) to ~300 J/m (20 wt%), indicating a trade-off between stiffness and toughness. Despite this reduction, all composites exceeded the minimum Izod impact strength requirement for automotive polypropylene copolymers (≥75 J/m, SNI 8432:2022). Overall, this study highlights the feasibility of valorizing both post-consumer plastic waste and wood dust into functional, sustainable composites for automotive components