Jurnal Riset Kimia

Front Matter

Editor in Chief JRK — 2023-10-17

September

Fitokimia, Kadar Fenolik Total, dan Flavonoid Total serta Aktivitas Antioksidan Ekstrak n-Heksana Rimpang Temu Hitam (Curcuma aeruginosa Roxb)

Auliya Ilmiawati — 2023-10-17

The rhizome of black turmeric (Curcuma aeruginosa) is a plant rich in benefits and has been used as a herbal medicine to treat various health problems. This study aims to obtain the n-hexane extract of black turmeric rhizome and perform phytochemical tests, determine total phenolic and total flavonoid levels, as well antioxidant tests using the DPPH method. Extraction of n-hexane from black turmeric rhizome obtained yield of 4.88%, total phenolic content of 3.01 mg QE/g extract and total flavonoids of 6.31 mg QE/g extract. The phytochemical test obtained positive results for the presence of alkaloids and flavonoids; negative tannins, steroids/triterpenoids and saponins. Antioxidant tests using the DPPH method obtained the percentage of DPPH capture ranging from 76-78%, with the largest percentage value obtained when the extract concentration was 125 ppm, which was 78.02%. This shows that black turmeric n-hexane extract has weak antioxidant activity.

Pembuatan dan Karakterisasi BPAC (Banana Peels Activated Carbon) Sebagai Biosorben Logam Raksa (Hg) dengan Aktivator HCl

Putri Ade Rahma Yulis — 2023-10-17

Based on the 2021 Central Statistics Agency (BPS) about environment, there is still a high level of pollution, especially pollution in water. The pollution is dominated by heavy metal contaminants. This research was carried out to make and characterized biosorbents which were activated into activated carbon from banana peel waste called BPAC (Banana Peels Activated Carbon) with HCl activator. Activated carbon has many advantages as an adsorbent with time and cost efficiency in absorbed heavy metals. Activated carbon from banana peels that has been formed was tested for its characterization included tests for water content, ash content, and iodine absorption and compared with SNI standard activated carbon quality with results of 3.9% water content, 6.2% ash content and iodine absorption 563.6 mg/g. The functional groups were tested by FT-IR (Fourier Transform-Infra Red) with the result spectrum at the peak of 3334 cm^-1, 2921 cm^-1, 2853 cm^-1, 1575 cm^-1, 1375 cm^-1, and 1098 cm^-1which indicated the presence of functional groups such as (C-O); (C=O); (C-H); (O-H) of several compounds such as lignin, pectin, cellulose and galacturonic acid as active sites that can bind heavy metals such as mercury. Surface morphology of activated carbon was tested by SEM (Scanning Electron Microscopy) with 500x and 1000x magnification. Activated carbon that has been tested is then applied to artificial mercury metal waste to determine the adsorption power and effectiveness of the activated carbon. Mercury metal content before adsorption was 6.995 mg/L and after adsorption was 0.0084 mg/L which was measured used ICP-OES (Inductively Coupled Plasma – Optical Emission Spectrometry). The percentage effectiveness of BPAC (Banana Peels Activated Carbon) reaches 99.87% with an adsorption capacity of 0.698 mg/g. Based on the results of this percentage it can be said that BPAC is effective to be used as a metal mercury biosorbent.

Komposit Zeolit-Polivinil Alkohol sebagai Adsorben untuk Menurunkan Kesadahan Air Tanah

Anang Takwanto — 2023-10-17

Granular zeolite-polyvinyl alcohol (PVA) composites without glutralaldehyde and zeolite-PVA composites with the addition of glutaraldehyde were carried out in this study and used as adsorbents. This study aims to reduce groundwater hardness, determine the optimum zeolite size in composite mixtures, and determine the characterization of functional groups in composites. The stages of the research included: preparation and activation of zeolite with variations in zeolite sizes of 100, 60 and 45 mesh and variations in composition of zeolite-polyvinyl alcohol 1:1; 1:2; 2:1; 2:3 and 3:2. Furthermore, the preparation of PVA solution concentration of 9% and the formation of the composite. The results showed that the optimum size of the zeolite on the composite without glutaraldehyde was 60 mesh with a decrease in hardness of 68% while the ratio of the optimum zeolite-PVA composition was at a ratio of 3:2 with a decrease in hardness of 34 mg/L. The results of Langmuir and Freundlich isotherm analysis showed the presence of chemical bonds because the determination value (R²) of the adsorption isotherm was > 0.9. The results of functional group characterization showed OH- in the zeolite-PVA composite without glutaraldehyde at a wavelength of 3363.01 cm^-1 while in the composite with glutaraldehyde at a wavelength of 3345.89 cm^-1. The C=C functional group appeared at a wavelength of 1628.73 cm^-1 for the zeolite-PVA composite without glutaraldehyde and 1635.86 cm^-1 for the composite with glutaraldehyde. At a wavelength of 788.70 cm^-1 and 794.40 cm^-1, the Si-O symmetric stretching vibrations show in the zeolite structure.

Identifikasi Struktur Protein Spike Varian Baru SARS-CoV-2 secara Bioinformatika dalam Pengembangan Kandidat Terapi COVID-19

Taufik Muhammad Fakih — 2023-10-17

Despite the relatively slow evolutionary rate of SARS-CoV-2 in comparison to other RNA viruses, the extensive and rapid transmission during the COVID-19 pandemic has led to the emergence of significant genetic diversity since the virus first infected the human population. This has resulted in various variants, such as Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1), among others. Of particular concern are the Delta Variant and newly recognized Variants of Concern (VOCs), including lineages of B.1.617.2, as well as other VOCs discovered through local transmission, such as Epsilon (B.1.427/29-US) and B1.1.7/E484K-UK. The interactions between these variants and the spike protein of SARS-CoV-2, as well as the Angiotensin-converting enzyme 2 (ACE2), have become a primary focus in understanding the infection and spread of the SARS-CoV-2 virus. This research aims to comprehensively identify, evaluate, and explore the structural characteristics of the macromolecular spike protein of SARS-CoV-2 in the Beta, Gamma, and Delta variants using bioinformatics approaches. The methods employed in this study include homology modeling, molecular docking simulations, and molecular dynamics simulations. The research findings indicate that the spike protein of SARS-CoV-2 in the Gamma variant exhibits a strong affinity for ACE2. Therefore, this study is expected to serve as a reference for designing effective vaccine or antiviral candidates targeting various SARS-CoV-2 variants in the treatment of COVID-19 infections.

Antibacterial Activity against Gram-Positive and Gram-Negative Bacteria and Biolarvicide to Aedes aegypti from Cocok Bubu (Elatostema rostratum (Blume) Hassk) Leaves Extract

Lela Lailatul Khumaisah — 2023-10-17

Tropical diseases are infectious diseases that commonly occur in tropical climates. Infectious diseases are caused by bacteria, viruses, parasites, and are transmitted by several vectors. There are 8 neglected tropical diseases (NTDs) that have spread in Indonesia. Therefore, massive efforts are needed to overcome this disease. Active plant substances have long been popular in treating various diseases. Cocok Bubu (Elatostema rostratum (Blume) Hassk) is an endemic plant of Indonesia. Ethnobotanical studies of this plant are used to treat fever and diarrhea. But, there are no pharmacological studies on previous research because this species belongs to a limited distribution plant. However, Elatostema has a secondary metabolite with various pharmacological activities. This study aims to determine the activity of antibacterial and biolarvicides from Cocok bubu leaf extract. The extraction using the maceration method with acetone, phytochemicals screening, toxicity test using BSLT, antibacterial test with disc diffusion to Escherichia coli, Staphylococcus aureus, Streptococcus mutant, and Streptococcus sanguinis, and biolarvicide activity against Aedes aegypti. Based on the results, Cocok bubu leaf extract contains flavonoids, alkaloids, saponin, tannin, terpenoids, and steroids with a toxicity of 758.45 ppm. From antibacterial activity results, Cocok bubu exctract had the best inhibition zone against Staphylococcus aureus (10 – 18 mm). According to the biolarvicide test, it is effective as a biolarvicide to Aedes aegypti with LC₅₀ 51.099 ppm and LT₅₀ of 5 h 43 min. This study shows that Cocok bubu was more effective for treating and preventing NTDs in Indonesia, especially dengue and chikungunya fever in the future.

Laju Reaksi Penghilangan Fosfat pada Limbah Cair Artifisial NPK Menggunakan Sistem Floating Treatment Wetlands

Sugiarti — 2023-10-17

Floating Treatment Wetland (FTW) is a form of wetland that functions to remove waste such as Nitrogen (N element) and Phosphorus (Phosphorous/P element) waste by utilizing plant roots as pollutant absorbers. This study aims to examine the reaction rate of phosphate removal from synthetic P waste through FTW. The water plants used were water jasmine (Echinodorus palifolius) and banana (Helliconia psittaforum). Four FTW ponds are filled with synthetic P waste. The first pond is a control pond, while the second pond is filled with FTW without plants, and the third and fourth ponds are filled with each of the aquatic plants mentioned above. The study was conducted from July to mid-August 2019. Water samples were taken in four pools five times in the first week, three times in the second week and twice in the third to sixth weeks. The parameters measured are water temperature, pH, Oxidative Reductive Potential (ORP) and phosphate. The data analysis carried out was calculating the phosphate reaction rate for each measured sample. The rate of phosphate decreases in proportion to the decrease in phosphate concentration in the test pond. Aquatic plants have been proven to remove phosphate from synthetic waste by using it as a nutrient for plant growth.

Pemanfaatan Zeolit Alam Ende Sebagai Katalis dalam Pirolisis Polietilena dari Sampah Plastik

Gregorio Antonny Bani — 2023-10-17

Pyrolysis is one way to minimise plastic waste. This process requires a catalyst such as zeolite. Natural zeolite needs to be activated to increase its catalytic activity. Therefore, this research was carried out by activating Ende's natural zeolite using 1% hydrofluoric acid (HF), 6M hydrochloric acid (HCl), and 1M ammonium chloride (NH₄Cl) to be used as catalysts in the pyrolysis of polyethylene from plastic waste. Pyrolysis was carried out at operating temperatures of 300 ^oC, 350 ^oC, 400 ^oC, and 450 ^oC, and treated with a catalyst composition of 0%, 5%, 10%, and 15% from 1000 grams of polyethylene. Based on the results of the study, it was concluded that activation of Ende's natural zeolite could change the chemical and physical properties of Ende's natural zeolite, including crystallinity, surface area, pore volume, and pore radius, and acidity to serve as a catalyst. Treatment of 10% catalyst from 1000 mg of plastic at an operating temperature of 400^oC reduced the activation energy to 4.371.1 cal/mol and produced 80% more paraffin fraction in polyethylene pyrolysis oil from plastic waste.

The Extracted Pectin from Ambarella Fruit Peel (Spondias dulcis) as Biosorbent in Adsorption of Cu(II) Metal Ions

Trisna Kumala Sari — 2023-10-17

Heavy metals are known to seriously injure land plants and animals, including humans, as well as marine species when present in contaminated water. For the batch adsorption technique used in this study, Cu(II) ions were removed from an aqueous solution using an inexpensive environmentally friendly adsorbent prepared from the extracted pectin of ambarella fruit peel. The functional groups of the extracted pectin were studied using Fourier Transform Infrared Spectroscopy (FT-IR). Operational conditions like pH, contact time, and initial adsorbate concentration were investigated. FTIR characterization showed that pectin was successfully extracted from ambarella fruit peel with the appearance of the peaks at 3331.36 cm^-1, 2924.02 cm^-1, 1727.38 cm^-1, 1626.20 cm^-1, 1329.31cm⁻¹, 1232.43cm⁻¹, 994.18 cm⁻¹and these peaks have similar characteristic with a commercial pectin. The maximum uptake of Cu(II) ions was obtained at a pH of 4, a contact time of 90 min, an initial metal concentration of 150 ppm. The extracted pectin has an adsorption capacity of 6.5860 mg/g for the removal of Cu(II) ions from aqueous solution under the optimum adsorption conditions. In addition, the data obtained from contacting the extracted pectin of ambarella fruit peel in Batang Arau River water showed an adsorption capacity of 0.0376 mg/g. Therefore, the pectin that was extracted from the peel of the ambarella fruit could be used to filter out Cu(II) ions from aqueous solutions.

Synthesis of Mg-doped TiO2 Using a Hydrothermal Method as Photoanode on Bixin-Sensitized Solar Cell

Winda Rahmalia — 2023-10-17

Titanium dioxide (TiO₂) with magnesium (Mg) doping for dye-sensitized solar cell (DSSC) photoanode application has been synthesized. DSSC components used in this study were photosensitizer (bixin), electrolyte (), cathode (platinum), and photoanode (Mg-TiO₂). This research aims to determine the characteristics of Mg-doped TiO₂ photoanode with variations in dopant concentration based on the results of XRD and DR/UV-Vis analysis, as well as to determine the maximum efficiency conversion energy of DSSC using Mg-doped TiO₂ and undoped TiO₂ as photoanodes. The synthesis of TiO₂ and Mg-TiO₂ was carried out using the hydrothermal method with variations in the concentration of Mg dopant of 0, 0.5, 1, and 2% based on the molar ratio. The presenceof 2% of Mg in anatase TiO₂ paste decreased the TiO₂ band gap from 3.15 to 2.60 eV. Analysis results show that adding Mg dopant decreased the crystal size. Mg dopants on TiO₂ could also form new energy levels, which reduced the band gap energy of TiO₂. In addition, the increased concentration of Mg dopants also shifted the absorption capacity of TiO₂ from the ultra-violet (UV) wavelengths region to the visible light area. The maximum energy conversion efficiency of the DSSCs with Mg-doped TiO₂ photoanode of 0.5, 1, and 2% are 0.045; 0.070, and 0.172%, respectively, where these three efficiency values are higher than undoped TiO₂ (0.017%). The results proved that the presence of Mg dopants on the TiO₂ photoanode can increase the efficiency of DSSC.

Synthesis and Characterization of Adsorbent Materials Magnetite Mercaptosilicate Ion Imprinted Polymer as Cadmium Ion Adsorbent

Nabela Viviana — 2023-10-17

Cadmium (Cd) is a toxic heavy metal with the active property of reacting with other components so that cadmium residues can quickly enter the food chain and cause cardiovascular, kidney, and cancer diseases. The purpose was to synthesize the magnetite mercaptosilicate ion imprinted polymer adsorbent material by forming Ion-Imprinted Polymer as a template, to analyze the characterization results using XRD and SEM-EDS, and to determine the adsorption test results for Cd metal ions. The results of the characterization of XRD show that there is a broad peak at a diffraction angle of 2θ= 20-220 with an amorphous structure, which is silica, and there is a high peak at a diffraction angle of 2θ= 35.55140 which indicates magnetite. The results of SEM analysis with magnifications of 500x, 1000x, and 5000x showed that the surface morphology of the particles was not uniform. For the EDS results, it can be seen that the components of the magnetite mercaptosilicate ion imprinted polymer material are elements C, O, Si, S, and Fe, with a mass percentage of 25.0%; 41.2%; 29.9%; 3.28% and 0.8%. The results of the adsorption test for the Magnetite-IIP-Mercaptosilika Material were able to adsorb Cd ions with the highest adsorption capacity of 10.536 mg/g at a concentration of 100 mg/L. Then the selectivity coefficient value of the Ion Cd metal ion is 2.32 greater than 1, indicating that the selectivity of the magnetite mercaptosilicate ion imprinted polymer material is much higher for Ion Cd metal ions than for Cu and Cr ions with a selectivity coefficient of 0.1 and 0.26.

Pengaruh Perbandingan Massa Silikon/Silika terhadap Karbon pada Kinerja Anode Baterai Litium Ion dari Sekam Padi

Achmad Rochliadi — 2023-10-17

This study aims to investigate the possible utilization of silica (SiO₂) and silicon (Si) derived from rice husks as anode materials in lithium-ion batteries (LIBs). SiO₂ and Si have impressive theoretical capacities of 1965 and 4200 mAh/g, respectively. However, their direct use as LIBs anodes faces challenges such as substantial volume changes during battery charging and discharging, as well as low electrical conductivity. Consequently, a common approach is to create nanostructures of SiO₂ and Si, such as nanoparticles, nanowires, and nanotubes, and combine them with conductive matrices like carbon-based materials. In this study, the Si/SiO₂/C composite was synthesized from rice husks, taking into account the mass ratio of Si/SiO₂ to C. The process involved first separating SiO₂ and C from rice husks and then synthesizing the composite using the ball mill method and activated molten salt aluminothermic reduction (AlCl₃/NaCl). X-ray Diffraction (XRD) analysis confirmed the successful synthesis of the composite, as indicated by characteristic peaks of the constituent compounds. Scanning Electron Microscope (SEM) imaging showed non-uniform morphology with varying particle sizes. Tests results demonstrated that the Si/SiO₂/C composite with a 3:1 ratio exhibited the most promising performance as a LIB anode, maintaining a high capacity of 280.48 mAh/g with a Coulombic Efficiency (CE) of 99% after 50 testing cycles. These findings suggest that silica and silicon compounds derived from rice husks hold great potential as efficient and durable anode materials for LIBs applications.