DISCOVERY LEARNING MODELS FOR TRAINING SCIENCE LITERACY OF STUDENTS IN COLOID MATERIALS

Scientific literacy ability is one of the abilities that must be mastered by students in the 21st century, to be able to solve problems in everyday life using the chemical concepts they are learning. Therefore, we need a learning that is able to relate learning material to the processes of everyday life, namely the effectiveness of the Discovery Learning model. The purpose of this research is to improve students' scientific literacy skills in colloid material. This Discovery Learning model focuses on student activities in learning with the teacher as the facilitator. The research method used was the pre-experimental method with a one-group pre-test-post-test design. The population in this study were all 52 students in class XI IPA at SMA Negeri 3 Muara Muntai in the 2022/2023 academic year, which were divided into 2 classes selected using a saturated sampling technique. The instruments used to measure students' scientific literacy skills are essay test techniques and non-test techniques in the form of student observation sheets and student response questionnaires. The results showed that the increase in students' scientific literacy skills was in the medium category with an effect size classified as a very strong category, as well as a positive response from students. Based on the research that has been done, it can be concluded that the effectiveness of the Discovery Learning learning model can increase students' scientific literacy in colloidal material.   Keywords: Scientific Literacy, Discovery Learning Model, Colloi

THE EFFECTIVENESS OF STEM AND RHIZOME EXTRACT OF KECOMBRANG (Etlingera elatior) AS A NATURAL PRESERVATIVE FOR TILAPIA (Oreochromis niloticus) MEAT

Tilapia contains protein and has a high nutritional content, including minerals, vitamins and unsaturated fats. However, this fish is easily damaged and rotten. This is caused by the activity of enzymes, microorganisms, or oxygen oxidation. Therefore, it is necessary to use preservatives so that the fish does not spoil or rot quickly. One of the potential natural preservatives is the kecombrang plant, especially the stems and rhizomes which contain bioactive substances. This plant has antibacterial properties that can help slow down the decline in fish quality. This study aims to determine the effectiveness of kecombrang stem and rhizome extract as a natural preservative in tilapia meat. The effectiveness of kecombrang stem and rhizome extracts was determined by soaking tilapia meat in kecombrang stem and rhizome extracts at various times of 0, 3, and 6 hours. The protein content of tilapia meat was measured by the biuret test. The results of this study indicated that the percentage of protein degradation inhibitors in kecombrang stem extract was 30.1% for 3 hours and 17.8% for 6 hours while in kecombrang rhizome extract was 34.2% for 3 hours and 22.6% for 6 hours. This shows that kecombrang rhizome extract is more effective as a natural preservative for tilapia meat compared to kecombrang stem extract.   Keywords: Tilapia, kecombrang stem, kecombrang rhizome, natural preservative, biure

KUALITAS PAPAN KOMPOSIT PLASTIK BERDASARKAN RASIO LIMBAH PLASTIK POLIPROPILENA (PP) DENGAN CAMPURAN SERBUK KAYU SENGON (Paraserianthes falcataria L.I.C. Nielsen) DAN SEKAM PADI (Oryza sativa)

The need for wood and plastic products is increasing, it is necessary to optimize the utilization of waste by processing it into plastic composite boards. This study aims to determine the best composition with raw materials of sengon wood powder (Paraserianthes falcataria L.I.C Nielsen) and rice husk powder (Oryza sativa) as filler with a ratio of 50% : 50% and polyprophylene plastic (PP) as a matrix. This treatment uses 3 compositions, P1 (40 % PP : 60 % SS) P2 (50% PP: 50% SS), and P3 (60% PP: 40 % SS ) was hot pressed with a pressure of 30 bar for 20 minutes at a temperature of 180°C with 3 replications for each treatment. The best result was obtained in the P3 (60 % PP : 40 % SS) with an average density value of 0.83 g/cm3, moisture content 1.52%, water absorption 32.16%, thickness swelling 9.34%, MoE 4,057.85 N/mm2, MoR 42.39 N/mm2 and IBS 0.21 N/mm2 Some test results have met plastic composite board standards according to JIS Particle Board A 5908-2003, JIS Plastic Board A 5741-2006 and SNI Plastic Board SNI 8154-2015

Mini Review: Citrus sinensis Sebagai Bioreduktor Dalam Green Synthesis Nanopartikel

Green synthesis is an eco-friendly approach that provides a viable alternative to traditional physical and chemical methods for the production of nanoparticles. This technique employs non-toxic and safe materials, such as plants, microorganisms, algae, bacteria, yeast, and fungi, to generate stable and less toxic nanoparticles. Citrus sinensis, commonly known as sweet orange, is a plant that contains various active compounds. These bioactive compounds can be extracted and used as bioreductants in green synthesis of nanoparticles. This mini review aimed to provide an overview of the current state of research on the utilization of Citrus sinensis as a bioreductant in the production of nanoparticles. A systematic search strategy was employed to identify research articles that met the criteria of discussing green synthesis of nanoparticles with Citrus sinensis as a bioreductant. The nanoparticles produced using Citrus sinensis extract can be either metal nanoparticles or metal oxide nanoparticles. The review highlights the distribution of nanoparticles produced with Citrus sinensis extract, their applications, and the extraction process of Citrus sinensis commonly employed in green synthesis of nanoparticles. Hopefully this review serves as a useful reference for researchers and practitioners who are interested in employing the Citrus sinensis plant as a bioreductant in the green synthesis of nanoparticles

OPTIMASI WAKTU PENGONTAKAN PADA MODIFIKASI SINTESIS NANOPARTIKEL PERAK DENGAN L-Sistein

Synthesis of L-cysteine ​​modified silver nanoparticles (AgNPs) investigated. The reducing agent used in the synthesis of silver nanoparticles is trisodium citrate. The reaction between silver nitrate and trisodium citrate is indicated by a color change from clear to yellow. AgNPs were prepared with optimum contact time variations. The result of  the UV-Vis spectrophotometer characterization showed that L-cysteine ​​modified silver nanoparticles (AgNPs) with an optimum contacting time of 7 hours. L-cysteine ​​modified silver nanoparticles (AgNPs) were applied as colorimetric histamine sensors. Keywords: Silver Nanoparticles (AgNPs), Optimization, UV-Vis Spectrophotometer. &nbsp

IDENTIFIKASI SENYAWA METABOLIT SEKUNDER DAN UJI AKTIVITAS ANTIOKSIDAN PADA LIMBAH KULIT BUAH

Indonesia adalah negara yang menyimpan kekayaan sumber daya hayati, terutama buah tropika. Tingginya keragaman tanaman buah di Indonesia menghasilkan berbagai manfaat untuk kesehatan, di antara lain sebagai antioksidan. Tidak hanya terdapat dibuah, kulit buah juga mengandung antioksidan untuk kesehatan. Manfaat antioksidan bagi tubuh di antaranya untuk melindungi sel-sel tubuh dari kerusakan yang diakibatkan oleh radikal bebas. Senyawa radikal bebas terdapat dalam lingkungan kehidupan sehari-hari manusia. Polusi udara merupakan salah satu contoh sumber radikal bebas. Sumber radikal bebas lainnya yaitu racun, paparan sinar matahari berlebih, asap rokok, makanan yang digoreng, dan obat-obat tertentu. Tujuan dari literature review ini adalah untuk mengetahui metabolit sekunder dan aktivitas antioksidan yang terdapat pada limbah kulit buah sebagai mengakal radikal bebas. Metode yang digunakan dalam karya tulis ini penelusuran pustaka melalui database Google dan Google Scholar dengan menggunakan keyword. Jurnal yang telah ditemukan dilakukan screening dengan kriteria inklusi dan eksklusi. Berdasarkan hasil dari berbagai penelusuran yang dicantumkan dalam artikel menunjukkan aktivitas antioksidan yang tinggi terdapat pada limbah kulit buag naga yaitu nilai IC50 adalah 2,69 ppm

BIOSORPSI LOGAM BERAT Cr(VI) MENGGUNAKAN BAKTERI Streptococcus mutans

The research about the biosorpsion of hexavalent chromium heavy metal [Cr(VI)] with Streptococcus mutans bacteria has been carried out. Biosorption has been done by exposure of chromium to broth culture, the consentration and optimum time happened on the 4 day with the biosorption percentage of Cr(VI) by Streptococcus mutans bacteria was obtained at a concentration of Cr(VI) 5 ppm, with a percentage of 90.80%. It shows Streptococcus mutans has potential as biosorbent of Cr(VI).   Keywords: Biosorption, Cr(VI), Streptococcus mutan

UJI FITOKIMIA DAN TOKSISITAS TERHADAP ARTEMIA SALINA DARI EKSTRAK METANOL JARINGAN DAUN MANGROVE RHIZOPHORA MUCRONATA

Mangrove plants can produce bioactive compounds that have the potential to be developed into medicinal plants. Mangrove Rhizopora mucronata is one of the mangrove species that has bioactive compounds. This study aims to determine the content of secondary metabolites by conducting phytochemical tests and toxicity tests on Artemia salina (shrimp larvae) in the methanol extract of Rhizopora mucronata mangrove leaves. The sample used was Mangrove Rhizopora mucronata obtained from sambera mangrove trees from Muara Badak, East Kalimantan. Extraction was carried out using the maceration method, where samples of  Rhizopora mucronata mangrove leaves were extracted with methanol for 3 x 24 hours. The methanol extract obtained was evaporated using a rotary evaporator. Furthermore, the methanol viscous extract was carried out by phytochemical test using color test method and toxicity test using BSLT. Based on the results of phytochemical tests, the methanol extract of mangrove leaves Rhizopora mucronata contains alkaloids and saponins. The toxicity of the methanol extract of Rhizopora mucronata mangrove leaves is in the moderate category with an LC50 of 48,165 ± 52,25 ppm. Rhizopora mucronata mangrove leaf extract contains active compounds that have the potential to be developed as alternative and anticancer drugs   Keywords: Mangrove Rhizopora mucronata, methanol extract, active chemical content, toxicit

SKRINING FITOKIMIA DAN UJI TOKSISITAS EKSTRAK KASAR, FRAKSI N-HEKSANA, ETIL ASETAT, DAN METANOL-AIR DAUN KIRINYUH (Chromolaena odorata (L.) King & H.E Robins)

Kirinyuh leaves (Chromolaena odorata (L.) King & H.E Robins) is one of the plants of the Asteraceae family that is commonly used by the community as a wound healing medicinal ingredient and has antioxidant and antibacterial activities. This research was conducted to determine the type of secondary metabolite compounds contained in the crude extract, n-Hexane, ethyl acetate and methanol-water fraction kirinyuh leaves (Chromolaena odorata (L.) King & H.E Robins) and determine the level of toxicity against to Artemia salina L. using the BSLT method. Phytochemical test results of crude extract leaves kirinyuh (Chromolaena odorata (L.) King & H.E Robins) contain alkaloids, flavonoids, steroids, and phenolics. The n-Hexane fraction contains steroids and quinones. The ethyl acetate fraction contains flavonoids and phenolics. The methanol-water fraction contains flavonoids, saponins and phenolics. Based on toxicity tests, crude extract, n-hexane, ethyl acetate fractions of kirinyuh leaves is highly toxic with successive LC50 values of 2.88 ppm, 8.12 ppm and 6.86 ppm, then the methanol-water fraction is toxic with an LC50 value of 186.76 ppm.    Keywords: Kirinyuh leaves, phytochemicals, toxicit

OPTIMASI pH DAN WAKTU KONTAK OPTIMUM ADSORBEN Fe3O4-AH TERHADAP ION LOGAM Pb2+

Optimization of pH and optimum contact time of coated magnetite adsorbent (Fe3O4-AH) against metal ions Pb2+ has been carried out. Humic acid-coated magnetite adsorbent (Fe3O4-AH) was prepared using the coprecipitation method with a mass ratio of 1:2 (w/w) and the separation process using an external magnet. Optimization was carried out by batch method using a Pb solution with a concentration of 50 mg/L and an adsorbent mass of 0.1 gram Fe3O4-AH. The test results show that the optimum pH is at pH 5 with % adsorption of 97.70% and the optimum contact time is at 20 minutes with % adsorption of 99.89%.   Keywords: humic acid, magnetite, adsorptio