Indo. J. Chem. Res.
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Isolation of Carrageenan from Eucheuma cottonii by Variying Alkaline Solutions
Full text linkThe carrageenan can be isolated by combining alkaline KOH, NaOH, and Ca(OH)2 solutions. Alkaline solutions of KOH: NaOH, KOH: Ca(OH)2, and NaOH: Ca(OH)2 were combined to extract carrageenan. The amount of the solution was varied, the carrageenan groups were characterized using FTIR, and the carrageenan’s gel strength was tested. The extraction results obtained the highest yield in the combination of alkaline solutions Ca(OH)2 80%+KOH 20%, which is equal to 70.18% FTIR test results for carrageenan produced from the extraction of Eucheuma cottonii seaweed showed absorption showing the type of kappa (κ) carrageenan. The highest gel strength test results were obtained in an alkaline solution of Ca(OH)2 80%: NaOH 20%, which was 252.5 g bloom, and the lowest was made in a solution of Ca(OH)2 80%: KOH 20%, which was 21.0 g bloom
Hydrothermal Synthesis and Characterization of Sodalite from Feldspar Mesawa Minerals
Full text linkThe mineral feldspar is a potential raw material in zeolite synthesis because of the high content of SiO2 and Al2O3. Characterization of X-ray diffraction (XRD) and X-ray fluorescence (XRF) on Mesawa feldspar minerals showed high crystallinity and aluminosilicate composition. The synthesis process uses the hydrothermal method with various times and concentrations of NaOH. The sample was mixed with NaOH, stirred until homogeneous at 300 rpm for 1 hour, and transferred to an autoclave. The autoclave was tightly closed and heated in an oven at 170 °C for 72 hours. XRD and XRF analysis revealed that the feldspar mineral had changed to sodalite with a purity of 90.89% and 90.06%; with a yield of 80.89% and 87.36%. FTIR characteristics show a specific peak for sodalite at 422-460 cm-1 related to Si-O bond vibrations, and absorption bands at 698 and 719 cm-1 related to Al-OH vibrations. The SEM results confirmed the morphology of the sodalite resembling balls like raspberries". This research proves that the Mesawa feldspar mineral sample contains type 6 secondary building units, the same blocks as zeolite analcime and cancrinite, so it has the potential as an adsorbent for heavy metals and as a catalyst alternativ
Optimization of the Esterification Process of Crude Palm Oil (CPO) with Natural Zeolite Catalyst Using Response Surface Methodology (RSM)
Full text linkEsterification is one of the important processes in the production of biodiesel. This is done to ensure that the FFA content in CPO is less than 3%. The esterification reaction can be accelerated by using natural zeolite as a catalyst. Optimization needs to be carried out to select the appropriate conditions to reach the optimal region quickly. The purposes of this research are to analyze the impact of esterification time and the natural zeolite catalyst size on the reduction of FFA levels and find the optimal parameters in the CPO esterification through RSM. Esterification is operated by maintaining the reaction temperature at 60 °C, agitation speed at 150 rpm, and using a molar ratio of methanol:CPO of 6:1. The independent variables used in the research are esterification time (90, 110, 130, 150, and 170 minutes) and natural zeolite size (20, 40, 60, 80, and 100 mesh). The optimization results using RSM indicate that the optimum points in the study are at an esterification time of 170 minutes and a natural zeolite size of 97.3909 mesh
Synthesis, Microstructure, Optical Properties, and Sensitive Amoxicillin Detection of Carbon Dots
Full text linkThe detection of amoxicillin has been successfully carried out using C-dot fluorescence probes made from d-glucose and urea. The fluorescence probe has an intense bright blue emission under UV light at 395 nm and and depends on the excitation and depends on the excitation. Raman studies successfully showed a D peak at 1381 cm-1 and a G peak at 1586 cm-1 associated with graphitic and amorphous structures. The absorption peaks in UV-vis spectroscopy confirm transitions at 275 nm (π → π*) and 322 nm (n → π*) with the presence of conjugated C=C and carbonyl (C=O) functional groups. The results of the fluorescence test show a bright blue color, with its intensity measured at an excitation of 365 nm. This can be attributed to nitrogen incorporation on the surface of the C-dots derived from urea, resulting in a quantum yield of 54%. This fluorescence probe is highly sensitive in detecting amoxicillin, as evidenced by the successful detection of AMX at concentrations of 10–30 μM and a resulting LOD of 5.75443×10−7 nM. The microstructure shows a uniform size of C-dot nanoparticles, and C-dot modeling was created. C-dot probes have an LOD of 5.75443×10−7 nM, indicating high sensitivity in detecting AMX
Evaluation of Lead (Pb) Bioaccumulation Levels by sea grass (Enhalus acoroides) at Tulehu Village Port
Full text linkThis research aims to study the level of heavy metal Pb bioaccumulation by sea grass (Enhalus acoroides) in the waters of Tulehu Village, Central Maluku Regency, where the type of particles and Pb content in sediment, roots and leaves are important variables for studying the accumulation and translocation of Pb metal ions by sea grass. Lead (Pb) content in sediment, roots and leaves of sea grass was measured using an atomic absorption spectrophotometer. The ability to accumulate and translocate lead (Pb) in sea grass (Enhalus acoroides) is known from the BCF (bioconcentration factor) and TF (translocation factor) values. The results of the study showed that the type of sediment particle grains at point I was 2.92% gravel, 86.67% sand, 26.67% mud, the size of sediment grains at point II was 16.67% gravel, 82.94% sand, 2.35% mud, and the size of sediment grains at point III was 19.77%, 64.58% sand, 1.04% mud. The Pb metal content produced at point I ranged from 4.80 mg/kg, point II ranged from 4.85 mg/kg and point III ranged from 4.44 mg/kg. The BCF values obtained at points I, II, and III were respectively 0.55; 2.20; 2.12
Potential of Shredded Ramie Fibers as Reinforcement in Recycled Polypropylene Composites: Analysis of Tensile and Bending Strength
Full text linkIn the development of composite technology, synthetic fiber reinforcers are gradually being replaced by natural fibers. This shift is driven by growing awareness of environmental issues and the scarcity of petroleum resources, prompting researchers to explore the potential of natural fibers. This study used scraped ramie fiber (SRK) as a reinforcer, with recycled polypropylene (PP) serving as the matrix. The mixture ratios used between PP/SRK (%) were as follows: 90/10, 80/20, 70/30, 60/40, and 50/50. Before use, the scraped ramie fiber (SRK) was subjected to pretreatment with 5% NaOH to improve the mechanical bonding. The hot press technique was used to fabricate the PP/SRK composite. The physical and mechanical properties of the PP/SRK composite were analyzed through weight, thickness, volume, density, tensile strength, and bending strength measurements. The results of physical measurements obtained density values for all samples between 0.73 - 0.76. The tensile test results showed a maximum stress value of 9.91 MPa and a strain value of 7.60% at the PP/SRK ratio 50/50. Then, the maximum modulus of rupture (MOR) was 23.49 MPa, and the modulus of elasticity (MOE) was 1.78 GPa at the PP/SRK ratio of 50/50
From Zircon Sand to Advanced Functional Materials: Synthesis and Characterization of Zirconium-Based Metal Organic Frameworks
Full text linkThis study presents an integrated approach for converting zircon sand into functional materials based on zirconium metal–organic frameworks (Zr-MOFs). Zirconium was extracted through three main steps: alkali fusion, water leaching, and nitric acid leaching, resulting in a precursor identified as Zr(OH)2(NO3)2·1.33H2O (ZON). Characterization using XRF, FTIR, XRD, and SEM-EDX revealed that ZON possesses a high zirconium content (94.87% relative to the total metal content) and distinct structural features. The ZON compound was subsequently utilized as a novel precursor in synthesizing of three types of Zr-MOFs: UiO-66, MOFs-801, and MOFs-808. Structural and morphological analyses indicated that all three MOFs were successfully formed with high crystallinity. These findings demonstrate that locally sourced zircon sand has strong potential as a sustainable and cost-effective raw material for MOF synthesis, while also bridging the knowledge gap between zirconium extraction and the development of sustainable materials chemistry based on local mineral resources
The Sediment Profile and Heavy Metal Content of Lead (Pb), Copper (Cu), and Silver (Ag) in The Waters of Saparua Island
Full text linkThis study determined the distribution levels of heavy metals Pb, Cu, and Ag in sediments in the waters of Saparua Island. It characterized the sediments in the seas of Saparua Island. Parameters are physical and chemical parameters of waters, determination of total organic carbon (TOC), and digestion of sediment samples for SSA testing. The results obtained levels of copper metal contained in the sediments from 0.1583–1.9531 mg/L and <4–78 ppm. The level of lead metal contained in the sediments in the waters of Saparua Island ranges from <12–26 ppm. Metal oxides, especially metal oxides formed from Cu, were found in sediments in the waters of Saparua Island with location points P.8 and P.9, namely CuO 0.0056% and 0.0031% and in sediments in Saparua Island waters with a value of 2Ɵ in sediment samples. P.2, P.3, P.6, P.8, P.9, and P.11 have the highest intensity which is the characterization of metal oxide 2Ɵ= 27.7464°, 29.4759, 26.2979, 26.6686, 26.7007, and 24.3695 indicate the presence of CaO (calcium oxide) phases at points P.2, P.3, and P.6. the SiO2 (silica) phase which is the most abundant metal in sediment samples P.8, P.9, and P.11 based on the XRF test
Synthesis of Cellulose Nanocrystals from Rice Husk Using Nitric Acid Hydrolysis
Full text linkRice husk residue has excellent potential as a raw material for making cellulose nanocrystals because of its relatively high cellulose content. This research focuses on determining the most effective hydrolysis conditions, especially the reaction time and nitric acid (HNO₃) content, in the synthesis of cellulose nanocrystals. This study also aims to determine the effect of variations in nitric acid concentration and hydrolysis time on the amount of product produced (yield) and the final size of cellulose nanocrystals. The process of making these nanocrystals involves three main stages, namely the removal of lignin using a 17,5% NaOH solution, followed by annealing using a 10% H₂O₂ solution, and finally breaking the cellulose bonds (acid hydrolysis) with a concentrated nitric acid solution of between 2% and 6% for different time periods (30 to 15 minutes). Product characterization using FT-IR and SEM has been carried out to confirm the presence of cellulose and determine the size of the nanocrystals formed. Experimental results show that the smallest cellulose crystal size achieved is between 0,93 to 65,10 μm, which was obtained through hydrolysis using 6% nitric acid for 150 minutes
Evaluation of the Antimicrobial Efficacy of Hibiscus sabdariffa L. Antiperspirant Preparations Against Staphylococcus epidermidis
Full text linkCommercial antiperspirant products commonly incorporate synthetic compounds, several of which have raised concerns due to their potential carcinogenicity. Moreover, the inclusion of natural antibacterial agents in these formulations remains limited. Hibiscus sabdariffa L. (Rosella), a plant rich in bioactive secondary metabolites, offers a promising natural alternative. This study aimed to evaluate the antibacterial efficacy of rosella-based antiperspirant formulations, particularly against Staphylococcus epidermidis, a key contributor to body odor. Three formulations (F1, F2, and F3) were developed and assessed based on several parameters: pH, organoleptic properties, homogeneity, spreadability, adhesiveness, and antibacterial activity against Staphylococcus epidermidis. The results demonstrated that the antiperspirant preparations complied with standard evaluation criteria. Furthermore, the antibacterial assay outcomes yielded statistically significant differences (p < 0.05) in the mean diameter of the inhibition zones, indicating that H. sabdariffa L. exhibited measurable antibacterial activity against S. epidermidis. These findings support the potential application of Rosella extract in developing natural and efficacious anti-perspirant products