Species Density and Lead (Pb) Pollution in Mangrove Ecosystem, South Kalimantan

Its crucial to get information about lead (Pb) heavy metal pollution from mining and oil palm plantation on species density in mangrove ecosystem, to anticipate its impacts. This study aimed is to compare the types and densities of vegetation in mangrove ecosystems allegedly due to mining in Setarap village, Tanah Bumbu Regency and oil palm plantations in Kuala Tambangan Village, Tanah Laut Regency. We also analysis the condition of waters (TDS, pH and DO) and organic content in sediments to acquire data from the South Kalimantan mangrove ecosystems. The results showed there were four species of true mangroves (Avicennia alba, Acanthus ebracteatus, Nypa fruticans and Rhizophora apiculate) could live well in the environment affected by mining or oil palm plantations. The species density for trees was low (933 ind/ha) for mangroves affected by coal mines, while those affected by oil palm plantations had higher densities (1,067 ind/ha). pH value of waters in affected area by coal mining showed more acidic value (pH 5.76) especially at the back, while those by palm oil plantations are more acidic (pH 6) in the estuary. Organic matter content in sediments affected by coal mines was in the range of 0.61-6.59%, while those affected by oil palm plantations showed higher values (0.12-2.19%). Lead heavy metal content (Pb) in waters affected by coal mines was 0.031-0.056 mg/L, while the area affected by oil palm plantations was of higher value (0.110-0.128 mg/L). Lead (Pb) levels in sediments indicate higher values than waters, which reach 3.512-6.046 mg/Kg (affected by coal mines), and in areas affected by oil palm plantations reaching 6.658-6.66 mg/Kg. The general conclusion is that vegetation densities in areas affected by coal mines are lower than oil palm plantations. The level of lead  (Pb) pollution in the sediments is higher than in the waters

One-pot Synthesis of Carbon-doped TiO2 with Bimetallic Ni-Ag co-catalysts in Photodegradation of Methylene Blue under UV and Visible Irradiation

Carbon modified-titanium dioxide (@C-TiO2) was prepared by one-pot procedure from TiCl4 and glucose under hydrothermal conditions at 150 ºC for 24 hours. The obtained @C-TiO2 was employed as support for Ni-Ag(3.0)@C-TiO2 nanocomposite (3.0 is the Ni/Ag molar ratio). The synthesized catalysts were characterized by means of XRD and UV-Vis DRS Spectroscopy. The XRD patterns of @TiO2 show the brookite as the main phase, meanwhile the main phase in the @C-TiO2, Ni-Ag(3.0)@TiO2 and Ni-Ag(3.0)@C-TiO2 nanocomposites were anatase. The band gap of the TiO2 sample slightly shifted to the visible range after the addition of C dopant or Ni-Ag(3.0) co-catalyst as indicated by UV-Vis DRS spectra. Ni-Ag(3.0)@C-TiO2 catalyst showed high photocatalytic activity for photodegradation of MB under both UV and visible irradiations at 60 ºC within 2 hours with maximum MB conversion of 67.5% and 54.1%, respectively. The synergistic action of C dopant or Ni-Ag(3.0) co-catalyst is believed to be important in the improvement of photocatalytic activity of @TiO2. Copyright © 2020 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).

The Promotion Effect of Cu on the Pd/C Catalyst in the Chemoselective Hydrogenation of Unsaturated Carbonyl Compounds

Highly efficient and selective hydrogenation of a,b-unsaturated carbonyl compounds to unsaturated alcohol using bimetallic palladium-copper supported on carbon (denoted as Pd-Cu(3.0)/C; 3.0 is Pd/Cu molar ratio) catalyst is demonstrated. Pd-Cu(3.0)/C catalyst was prepared via a simple hydrothermal route under air atmosphere at 150 °C for 24 h followed by reduction with hydrogen at 400°C for 1.5 h. The chemoselective hydrogenation of typical a,b-unsaturated carbonyl ketone (2-cyclohexene-1-one) and aldehyde (trans-2-hexenaldehyde), and chemoselective hydrogenation of FFald and (E)-non-3-en-2-one mixture demonstrated high productivity, leading to high selectivity of unsaturated alcohols. The presence of bimetallic Pd-Cu alloy phase with relatively high H2 uptakes was observed, enabling to preferentially hydrogenate C=O rather than to C=C bonds under mild reaction conditions. Pd-Cu(3.0)/C catalyst was found to stable and reusable for at least four reaction runs and the activity and selectivity of the catalyst can be restored to the original after rejuvenation with H2 at 400 °C for 1.5 h. 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).

Identifikasi Bijih Besi dengan Metode Geolistrik di Tanah Laut

Telah dilakukan penelitian identifikasi bijih besi di Desa Sumber Mulia, Kabupaten Tanah Laut. Penelitian bertujuan untuk mengetahui kedalaman dan sebaran serta kuantitas bijih besi di bawah permukaan tanah. Penelitian ini menggunakan metode geolistrik hambatan jenis konfigurasi dipole-dipole dan karakterisasi X-Ray Flourescence (XRF). Akuisisi data  dilakukan secara mapping menggunakan 3 lintasan yang berjarak 50 m tiap lintasan dengan panjang lintasan 100 m. Hasil pengolahan 3 titik dengan menggunakan software Res2dinv diperoleh nilai resistivitas yang terbaca 50-5992 Ohm.m, dan kedalaman yang diperoleh hingga 8 m. Nilai resistivitas bijih besi yang terbaca pada penampang berkisar antara 1500-4482 Ohm.m. Pada lintasan 1 terdapat beberapa bongkahan bijih besi dengan kedalaman >3 m, di lintasan 2 terdapat 1 bongkahan dengan kedalaman >5 m, sedangkan pada lintasan 3 tidak terdapat bijih besi. Hasil inversi disusun berurutan untuk menentukan arah sebaran, dan didapatkan bijih besi di lokasi penelitian menyebar ke arah Barat Daya. Sampel bijih besi diambil di setiap lintasan, untuk dilakukan karakterisasi XRF. Secara umum dapat ditemukan penyusun utama bijih besi adalah unsur logam, dimana unsur Fe merupakan penyusun utamanya dengan kuantitas rata-rata 98,58%

Potensi Nanokomposit Fe3O4@C dari Bijih Besi Sebagai Pendeteksi Kadar Glukosa

Sintesis nanokomposit Fe3O4@C dari bijih besi Tanah Laut dan sumber karbon dari gula pasir telah dilakukan dengan menggunakan metode kopresipitasi dan metode hidrotermal. Penelitian dilakukan untuk mengetahui karakteristik Fe3O4@C berbahan bijih besi. Sebanyak 6 g bijih besi digunakan sebagai bahan baku pembuatan Fe3O4. FeSO4.7H2O digunakan sebagai sumber ion Fe2+. Sampel diaduk dengan menggunakan temperatur 70oC dengan kecepatan adukan 450 rpm. Karbon (C) disintesis menggunakan metode hidrotermal pada temperatur 300oC dengan menambahkan etilon glikol sebagai surfaktan. Sampel Fe3O4 dan C digabung pada suhu 250oC selama 30 menit dengan kecepatan 500 rpm. Sampel  Nanokomposit Fe3O4@C dikarakterisasi menggunakan Vibrating Sample Magnetometer, Fourier Transform Infrared, Transmission Electron Microscopy, serta elektrokimia. Dari penelitian, diperoleh nilai magnetisasi saturasi sebesar 24,82 emu/g, jenis ikatan yang terdapat dalam nanokomposit Fe3O4@C adalah ikatan Fe-O, C=O, C=N dan O-H, distribusi ukuran partikel dalam rentang 5 nm – 20 nm, dengan rata-rata ukuran partikel 12 nm, serta nilai sensitivitas 0,285 mA/ppm

PEMANFAATAN FENOMENA SURFACE PLASMON RESONANCE (SPR) DENGAN MENGGUNAKAN NANOPARTIKEL MAGNETIK Fe3O4 UNTUK DETEKSI BIOMOLEKUL

The SPR phenomenon has been observed in the biomolecule detection coated by magnetic nanoparticles Fe3O4. The magnetic nanoparticles Fe3O4 mixed with PEG 4000 is used for biomolecule detection optimation. This research uses the attenuated total reflection (ATR) in the Krestchmann configuration with He- Ne laser beam of wavelength 633 nm. The SPR angle for prism/Ag layer system is 43,200±0,050 with a constant surface plasmon (SP) wavevector being 1,029�107 m-1. For the system due to the addition of the mixed layer of Fe3O4 magnetic nanoparticles, the SPR angle shifts to 43,400± 0,05o and a constant SP wavevector is 1,033�107 m-1. After reacted with α-amylase biomolecule, the SPR angle shifts to 44,300 ± 0,050 while the constant SP wavevector changes to 1,050�107 m-1

PENGARUH SUHU SINTERING TERHADAP SIFAT MEKANIK KERAMIK BERBAHAN LEMPUNG DAN ABU SEKAM PADI

Abstract.  Study about the influence of sintering temperature on mechanical properties of ceramics has been done using clay and rice husk ash. Limitation of mechanical properties tested is the comppressive strength. This is done in order to determine the effect of variation of sintering temperature to compressive strength of ceramic with clay and rice husk ash. In addition, the calculation of fuel density and shrinkage also performed in this study. Variation in the composition of clay and rice husk ash is made to see the maximum composition of these materials. The result shows that the density of the ceramic material on the composition of  clay and rice husk ash volume 100: 0, 90:10, 80:20, 70:30, 60:40, and 50:50 are 2.14; 2.01; 1.98; 1.88; 1.84; and 1.78 g / cm3 respectively. Shrinkage of ceramic material has ranges between 3.4% -11.4%. The value of maximum compressive strength of clay and rice husk ash ceramic at 7000C, 8000C, and 9000C sintering temperature are 115.58; 115.58, and 128.42 kg / cm3. This value conforms the standard if used for bricks. The greater the sintering temperature, the higher the compressive strength of the ceramic. The best composition of clay and rice husk ash is 70:30. This ceramic can be used as building material, especially in the swampy area because it has a lighter weight.   Keywords: Ceramics, Clay, Rich husk ash, comppressive strengt