Vienna Saraswaty

The increasing global demand for lithium and other critical elements has intensified the need for efficient and cost-effective exploration approaches. This study presents a preliminary hydrogeochemical assessment of lithium distribution in the Kulon Progo volcanic region, Southern Mountains of Java, Indonesia, using integrated ICP-OES, X-ray diffraction (XRD), and petrographic analyses. Surface water samples contain lithium concentrations ranging from 0.01 to 0.49 ppm, with the highest value recorded in Banyuasin well water. Associated trace elements, including strontium, boron, barium, magnesium, and cobalt, were also detected, reflecting complex water–rock geochemical interactions within the volcanic system. Volcanic rock samples contain 5–57 ppm Li, reflecting substantial spatial variability related to lithological differences across the study area. XRD and petrographic analyses provide mineralogical context for interpreting lithium distribution; however, specific lithium-hosting mineral phases could not be conclusively identified. The integrated geochemical and mineralogical data suggest that water–rock interaction is a key process controlling lithium mobilisation and distribution. This study provides the first baseline dataset on lithium distribution in the Kulon Progo volcanic region, identifies previously unrecognised lithium anomalies, and demonstrates the value of integrated hydrogeochemical approaches for preliminary lithium exploration in Indonesian volcanic terrain.

Mango peel extract was utilized for the fabrication of green zinc oxide nanoparticles (gZnO), exploited as a natural stabilizing and reducing agent. X-ray diffraction pattern confirmed the wurtzite crystalline phase with an average crystallite size of 12 nm. The scanning electron microscope observation revealed a spherical-like morphology of gZnO. The electrochemical behavior and EASA of bare and modified GCE were examined using cyclic voltammetry technique. The EASA of bare GCE increased from 0.118 cm2 to 0.182 cm2 after modification with gZnO. Measurement of uric acid (UA) using differential pulse voltammetry (DPV) in 0.1 M phosphate buffer pH 7.0, reveals a sharp oxidation peak at a potential of − 0.08 V (vs. Ag/AgCl). In addition, the UA peak current response was elevated 2.6-fold (from 3.7 µA to 9.75 µA) when analyzed at gZnO/GCE in comparison with bare GCE. The proposed electrode exhibits a narrow linear range at UA concentrations from 0.3 µM to 1.20 µM, with a low LOD value of 0.23 µM. These findings highlight the synergistic interaction between gZnO nanostructure and the conductive carbon matrix, enabling improved sensitivity and electron transfer kinetics. The gZnO/GCE platform offers a green, cost-effective, and non-enzymatic approach for UA detection in low-volume biological samples.

The current study introduces a one-pot technique for synthesizing an environmentally benign and cheap composite adsorbent, namely ZnO-PPAC, for the adsorption of Pb(II). The designated adsorbent was prepared by incorporating green synthesized zinc oxide (ZnO) nanoparticles on activated carbon-derived from pineapple peel. The prepared adsorbents were characterized using XRD, SEM, EDS, FTIR, and BET techniques. The XRD pattern verifies that the ZnO was successfully synthesized and immobilized onto the PPAC in a one pot synthesis system. The surface areas of ZnOPPAC and PPAC adsorbents were 13.62 m2/g and 961.96 m2/g, respectively. The FTIR evaluation of the ZnO-PPAC adsorbent revealed several characteristic absorption peaks corresponding to -OH groups, C-O groups, C=C groups, C-N groups, and M-O groups. It was revealed that the adsorption of Pb(II) on the ZnO/PPAC adsorbent would not require any pH adjustment. The adsorption kinetics demonstrated that the adsorption of Pb(II) ions on PPAC and ZnO-PPAC better fitted pseudo-second-order kinetics (R2 = 0.999, both for PPAC and ZnO/PPAC) and followed the Freundlich model (R2 = 0.989 and 0.987 for PPAC and ZnO/PPAC adsorbent). According to the Freundlich model, the adsorption of Pb(II) ions onto the designated adsorbents involves a multilayer process. The maximum adsorption capacities of ZnO/PPAC and PPAC were calculated as 769 mg/g and 667 mg/g, respectively. Thermodynamic analysis indicated an exothermic and spontaneous nature, as suggested by the negative values of ΔHº and ΔGº. In summary, both the prepared adsorbents greatly exhibited a high adsorption capacity of Pb(II) ions that can be used for environmental remediation.

A novel electrochemical sensor, chitosan based on molecularly imprinted polymer (MIP), was fabricated by electrodeposition of chitosan in the presence of methyl paraben (MP) on a zinc oxide/graphene nanocomposite (ZnO/GnC) modified screen-printed carbon electrode for selective detection of MP. The obtained chitosan-based MIP modified electrode, namely MIP/ZnO/GnC/SPCE was characterized by scanning electron microscopy, cyclic voltammetry, and differential pulse voltammetry. Under the optimized condition, the prepared sensor MIP/ZnO/GnC/SPCE exhibited satisfactory linearity with certain MP concentrations of 10 to 1000 μM and the limit of detection can reach 9.65 μM with a sensitivity of 0.00445 μA/μM.cm². This work shows that the incorporation of chitosan-based MIP with ZnO/GnC generates a synergistic effect, increasing the current response in comparison with unmodified SPCE. The developed sensor exhibited satisfactory reproducibility and repeatability. Furthermore, the developed electrode was successfully applied for the determination of MP in cosmetic products and shows similar performance in comparison to UV-visible spectrophotometry analysis. In conclusion, the chitosan-based MIP modified ZnO/GnC/SPCE is promising for monitoring the MP in cosmetic products.

In this paper, a simple and selective molecularly imprinted polymer film-based electrochemical sensor is made by electropolymerizing glycine in the presence of Sunset yellow (SY) as a template. The thin film electro-polymerization was characterized by cyclic voltammetry and square wave voltammetry. The optimization of important parameters, the removal of Sunset yellow from the developed electrode, analytical performance, and the analysis of a real sample are described. The results showed that the developed sensor is highly selective in the presence of interferents such as sodium chloride, glucose, benzoic acid, lemon yellow and tartrazine up to a 200-fold higher concentration. Under optimized conditions, the linear dynamic range was found to range from 2 to 100 μM, with LOD and LOQ values of 0.753 μM and 2.48 μM respectively. When the proposed sensor was used for the evaluation of a real sample (tomato sauce), a similar result was observed in comparison to high performance liquid chromatography evaluation, indicating the good reliability of our modified sensor. In summary, our proposed sensor is promising for the detection of SY in food products.

Hydroxyapatite from eggshells waste obtained by one stage of heating modified with ZnONPs on ACE (Hap-Esb/ZnONPs/ACE) can detect uric acid.

THE PHYSICOCHEMICAL CHARACTERISTICS OF RECYCLED-PLASTIC PELLETS OBTAINED FROM DISPOSABLE FACE MASK WASTES. The government policy to wear a face mask during the COVID-19 pandemic has increased disposable face mask wastes. Thus, to reduce such wastes, it is necessary to evaluate the physicochemical characteristics of disposable face masks wastes before the recycling process and the recycled products. In this study, physicochemical characterization of the 3-ply disposable face masks and the recycled plastic pellets after disinfection using 0.5% v/v sodium hypochlorite were evaluated. A set of parameters including the characterization of surface morphology by a scanning electron microscope (SEM), functional groups properties by a fourier transform infra-red spectroscopy (FT-IR), thermal behavior by a differential scanning calorimetry (DSC), tensile strength and elongation at break were evaluated. The surface morphological of each layer 3-ply disposable face mask showed that the layers were composed of non-woven fibers. The FT-IR evaluation revealed that 3-ply disposable face mask was made from a polypropylene. At the same time, the DSC analysis found that the polypropylene was in the form of homopolymer. The SEM analysis showed that the recycled plastic pellets showed a rough and uneven surface. The FT-IR, tensile strength and elongation at break of the recycled plastic pellets showed similarity with a virgin PP type CP442XP and a recycled PP from secondary recycling PP (COPLAST COMPANY). In summary, recycling 3-ply disposable face mask wastes to become plastic pellets is recommended for handling disposable face mask wastes problem.

Boenninghausenia albiflora is a well-known plant for being used in various traditional treatments. The plant is also reported to contain an essential oil which has a distinctive and pungent aroma. The present study aimed at investigating extraction yields, phytochemical compounds and antioxidants, and potential uses of B. albiflora leaves extracted with acetone solvent. Bioactive compounds of the leaf extract of B. albiflora were identified by GC-MS analysis while the antioxidant assay was measured by DPPH method. The extract obtained from acetone contained 30 compounds including coumarin group, 2-Isoprenyl-2,3-dihydro-furo [3,2-G] chromen-7-one (22.89% w/v) as the highest percentage compound. Other coumarins such as suberosin and dehydrogeijerin were also identified in this study. The IC₅₀ values of the leaves extract of B. albiflora was 194.3 ppm which was higher than propyl gallate. Thus indicating B. albiflora as potential sources of anti-cancer, anti-inflammatory and antioxidant.