UJI TOKSISITAS DAN UJI FITOKIMIA SPONS Haliclona sp. ASAL PULAU LEMUKUTAN KABUPATEN BENGKAYANG KALIMANTAN BARAT

Spons Haliclona sp. diketahui memiliki kandungan metabolit sekunder dengan aktivitas sitotoksik yang tinggi sehingga berpotensi untuk dimanfaatkan sebagai obat antikanker. Dalam penelitian ini, telah dilakukan uji toksisitas dan uji fitokimia terhadap ekstrak metanol spons Haliclona sp. asal Pulau Lemukutan Kabupaten Bengkayang Kalimantan Barat. Metode yang digunakan pada penelitian ini meliputi maserasi dengan pelarut metanol, uji fitokimia dan uji toksisitas. Uji toksisitas terhadap ekstrak metanol dilakukan dengan menggunakan metode Brine Shrimp Lethality Test (BSLT). Potensi ekstrak metanol spons sebagai antikanker dapat diketahui melalui tingkat toksisitasnya terhadap Artemia salina L. yang merupakan skrining pendahuluan menuju tahapan pengujian selanjutnya terhadap sel kanker yaitu sitotoksisitas. Ekstrak metanol dari spons Haliclona sp. bersifat toksik dengan nilai LC50 sebesar 70,1 ppm sehingga berpotensi dikembangkan dan diteliti lebih lanjut komponen aktifnya sebagai bahan baku obat antikanker. Kata Kunci: antikanker, Haliclona sp., toksisita

TiO2-rGO Composite for Photocatalytic Decolorization of Methylene Blue Under the Visible Light Illumination

Titanium dioxide-reduced graphene oxide (TiO2-rGO) was synthesized by hydrothermal method using TiO2 powder and rGO precursor from graphite rod by modified Marcano Method. The obtained TiO2-rGO photocatalyst was characterized by X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), and Diffuse reflectance UV (DRUV). Based on XRD diffractogram, it is known that TiO2 has an anatase crystal phase. In the FTIR spectrum, it was observed that there was an absorption peak at the wavenumber of 1630 cm-1 from the vibration (C=C) as an indication that the C atom was incorporated into the TiO2 structure. The incorporation of C atoms into the TiO2 structure to form TiO2-rGO causes the bandgap energy to decrease from 3.29 eV to 3.20 eV. The photocatalytic activity was tested against decolorization of methylene blue solution for 180 minutes under visible light illumination from a 50 watt LED lamp. Every 10 minutes, absorbance was measured using a UV-Vis spectrophotometer at a wavelength of 664 nm. TiO2-rGO photocatalyst has better photocatalytic activity with %D of 96.39% under UV light and 84.32% under visible light illumination, while TiO2 is only able to degrade 93.87% and 36.55%, respectively

Extraction and Characterization of Fe2O3 from Red Mud PT. Indonesia Chemical Alumina West Kalimantan

Red Mud is a term used for residues or waste materials from bauxite refining. One of the main compositions of red mud is Fe2O3. This study aims to obtain the optimum extraction of Fe2O3 conditions or hematite by using APDC ligands and knowing the characteristics of Fe2O3 generated. In this study, Fe2O3 extraction begins to determine the optimum pH and ligand concentration. The results of determining the optimum conditions showed pH 1 and ligand concentration of 0.5 M. Fe2O3 characteristics can be resolve through the characterization of Fourier Transformed Infra Red (FTIR), X-ray Diffraction (XRD) and X-ray Fluorescence (XRF). The results of FTIR characterization showed the stretching vibration of Fe-O Fe2O3 phase (570.50 cm-1 and 470.20 cm-1), XRD diffractogram showed the resulting crystal shape is rhombohedralsize is 27,08 nm, while the XRF characterization results showed the mass percent Fe2O3 before extraction is 42.48% and the mass percent Fe2O3 after extraction is 72.443%

SINTESIS TiO2/Ti TERDOPING LOGAM Fe3+ MENGGUNAKAN METODE ANODISASI DENGAN BANTUAN SINAR TAMPAK

Aktifitas fotokatalisis TiO2 dapat ditingkatkan dengan menggeser daerah serapan sinar UV ke daerah sinar tampak. Salah satu upaya untuk meningkatkan aktifitas fotokatalis TiO2 dengan penambahan dopan Fe3+. Penelitian ini bertujuan untuk mengetahui pengaruh penambahan dopan Fe3+ terhadap gugus fungsi, ukuran kristal, dan energi band gap. Metode yang digunakan adalah metode anodisasi menggunakan tegangan 40 V selama 1 jam dan dilakukan proses kalsinasi pada suhu 450oC selama 3 jam. Konsentrasi dopan Fe3+ yang digunakan sebesar 0,3%; 0,4%; dan 0,5% (b/v). Fotokatalis Fe-TiO2/Ti yang dihasilkan dilakukan uji aktivitas terhadap degradasi zat warna metilen biru dengan bantuan sinar tampak. Metilen biru divariasikan pada pH 9, 10, 11, 12 dan 13. Hasil karakterisasi FTIR menunjukkan Fe-TiO2/Ti 0,3% (b/v) memiliki vibrasi ulur gugus fungsi -OH 3399,68 cm-1 dan vibrasi ulur gugus fungsi Ti-O-Ti atau Ti-O 685,72 cm-1 dan 453,29 cm-1. Difraktogram XRD menunjukkan struktur fasa anatase dengan ukuran kristalit sebesar 124,58 nm. Hasil karakterisasi UV-Vis/DRS menunjukkan energi band gap TiO2 Degussa P25, TiO2/Ti, dan Fe-TiO2/Ti sebesar 3,22 eV; 3,16 eV; dan 2,91 eV. Hal ini menunjukkan bahwa dopan Fe3+ pada TiO2/Ti mempengaruhi nilai energi band gap.Kata Kunci: anodisasi, fotokatalis Fe-TiO2/Ti, metilen biru, titanium dioksid

Essential Oils Activity of Legundi Leaf (Vitex trifolia L.) as A Repellent for Rice Weevil (Sitophilus oryzae)

Legundi (Vitex trifolia L.) is a plant that contains essential oils. Legundi leaf essential oil has the potential as a more environmentally friendly rice lice repellent. The process of extracting essential oils from Legundi leaves uses the steam-water distillation method. The yield obtained from distillation is 0.10% with a bright yellow color, has a distinctive smell of Legundi oil with a specific gravity of 0.9065 gram/cm3. GC-MS search results showed that Legundi leaf essential oil contains 5 main components, namely 2-β-Pinene (16.18 %), trans-caryophyllene (13.75 %), β-Ocimene (11.16 %), Cyclohexanol (10.03%), and Eucalyptol (5.45%). Testing of repellent activity was carried out on rice lice with variations in volatile oil concentrations of 1%, 5%, 10%, and 20%. The results of the repellent test showed that the highest percentage occurred at a concentration of 20% (P4), which was 56.7%, with an application time of 120 hours (L5). Based on this, it can be said that the greater the concentration of the essential oil used, the higher the percentage of rejection of the population, this also indicates that Legundi leaf essential oil has lice repellent activity (Sitophilus oryzae)

Analysis of Lead (Pb) Heavy Metal Content in Tengkuyung Snail (Cerithidea obtuse) and Sediment in the Kuala Mangrove Area of Singkawang City

Tengkuyung (Cerithidea obtuse) is one of the many snails that live in mangrove areas, being a source of food and the economy, especially for people in coastal areas. Land and sea development and transportation activities have the potential to become a source of Pb contamination in tengkuyung and its environment. This study aims to determine the concentration of lead metal (Pb) in sediments and tengkuyung in the Kuala mangrove area of Singkawang City. Sampling was carried out at two station points. Measurement of heavy metal lead (Pb) in sediments and tengkuyung was carried out using atomic absorption spectrophotometry (SAA) method. The results showed that the content of lead (Pb) in the sediment and tengkuyung at station 1 was 0.0914 µg/g and <0.0070 (µg/g), while at station 2 it was 0.3927 µg/g and <0.0070 (µg/g). The content of Pb metal in tengkuyung meat still meets the eligibility for consumption because it is below the threshold according to SNI no. 7387 in 2009, which is 0.5 mg/kg (0.5 ppm)

Fe-doped TiO2/Kaolinite as an Antibacterial Photocatalyst under Visible Light Irradiation

In this work, undoped and Fe-doped TiO2 immobilized on kaolinite surface was successfully synthesized by sol-gel method with various Fe concentrations (0.05, 0.125, and 0.25 wt%). The effects of Fe doping into TiO2 lattice were thoroughly investigated by a diffuse reflectance UV-visible (DRS) spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, and X-ray diffraction (XRD). The optical band gap of undoped and Fe-doped TiO2/kaolinite is red shifted with respect to the incorporation of Fe3+ into the structure of TiO2 resulted band gap. The FTIR spectra shows a shift of peak at the wave number at 586 cm−1 and 774 cm−1 which is attribute of the Fe−O vibration as an indication of the formation of Fe-TiO2 bonds. Incorporation of Fe3+ cation into the TiO2 lattice replacing the Ti4+ ions, which induced a perturbation in anatase crystal structure, causes the change in the distance spacing of the crystal lattices dhkl(101) of 8.9632 to 7.9413. The enhanced photocatalytic performance was observed for Fe-doped TiO2/kaolinite compared with TiO2/kaolinite with respect to Escherichia coli growth inhibition in solution media under visible light irradiation. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0). 

Synthesis of Graphene Oxide/Polypyrrole (GO/PPy) from Used Batteries as Electrodes in Supercapacitor Cells

Fabrication with graphite-modified GO/PPy composites have been studied from used batteries using the Hummers method. This research was performance in four steps: graphite powder preparation, GO synthesis, GO/PPy composite synthesis, and supercapacitor cell manufacturing. The results of the study were characterized using X-Ray Diffraction (XRD) to see the character of the diffraction patterns formed by carbon batteries used before and after calcination and Fourier Transform Infra-Red (FTIR) to identify compound functional groups and conduct initial tests in the form of voltage, capacitance and life cycle by measuring charge and discharge times. The graphite preparation stage is carried out by the calcination method at 900°C to produce graphite with an angle of 2θ which is 26° with reflection from (d002). FTIR data showed that GO/PPy composites showed a successful combination of characteristics similar to pure polypyrrole and GO which included a broad absorption band located at 3500-2300 cm-1 which was estimated to be stretching the amine from polypyrrole and O-H group in the GO layer and the emergence of peaks new in the absorption band with a wave number 909 cm-1 is the CN vibration of the polymerized pyrrole. Meanwhile, based on the LCR meter measurement results in the best supercapacitor cells in the sampel GO/PPy ratio (3:10) with voltage value of 74.1 mV; a capacitance value of 15.14 µF and the best charge and discharge times

Analisis Bibliometrik Penelitian Bio-Sintesis Nanopartikel Perak (NP-Ag) di Indonesia

Tulisan ini menyajikan analisis bibliometrik terhadap artikel ilmiah yang terbit dalam kurun waktu 2011-2020 terkait penelitian bio-sintesis nanopartikel perak (NP-Ag) di Indonesia. Analisi bibliometric dilakukan terhadap 55 artikel ilmiah yang diperoleh melalui pencarian di database Scopus. Hasil analisis menunjukkan bahwa penelitian dan pengembangan bio-sintesis NP-Ag di Indonesia cukup mendapat banyak perhatian yang dibuktikan oleh adanya temuan berikut. Trend pertumbuhan artikel ilmiah terkait NP-Ag diperkirakan masih akan terus mengalami kenaikan untuk beberapa tahun ke depan. Posisi pertama untuk peneliti dan institusi yang paling produktif dalam memublikasikan artikel ilmiah adalah masing-masing ditempati oleh Handayani, W., dan Universitas Indonesia (UI). Handayani, W. juga diketahui merupakan peneliti yang mempunyai jaringan kolaborasi yang terbanyak, dan untuk kolaborasi tingkat insitusi, di tempati oleh Institut Teknologi Sepuluh November (ITS). Untuk jurnal sebagai sumber artikel ilmiah yang paling menonjol ditempati oleh “Biointerface Research in Applied Chemistry”. Lebih lanjut, hasil analisis konten terhadap 55 jurnal ilmiah yang terbagi menjadi tiga klaster menunjukkan bahwa penelitian bio-sintesis dimasa yang akan datang hendaknya melibatkan peneliti dari multidisiplin ilmu dengan hasil yang lebih inovatif, dengan arah dan skala pengembangan NP-Ag yang bersifat aplikatif, serta menuju arah industrilisasi