Caulerpa lentillifera is an edible and functional seaweed due to its high nutritional compositions and its biological activities.  In this study, C. lentillifera was evaluated for its proximate compositions (moisture, ash, protein, lipid and fiber contents) and its biological activities (antimicrobial, anti-oxidant, and toxicity). Moisture content, crude lipid, crude protein, and crude fiber were determined using oven method, soxhlet extraction, semi-micro Kjeldhal, and hydrolysis, respectively.  Fresh C. lentillifera of Natuna Island, Indonesia, showed its higher level content of ash, crude lipid, and crude fiber compared to that of fresh C. lentillifera of Penghu, Taiwan.  For its biological activity assays, the extracts were prepared from fresh and dry C. lentillifera (FC and DC).  Both of the extracts showed the broad spectrum of weak antimicrobial using well-diffusion agar tests and antioxidant activities using a modified linoleic acid emulsion system.  The toxicity for both extracts was determined using brine shrimp lethality test.  DC extract showed its very low toxicity level and there was no toxicity for FC.  Hemolytic activity was determined using red blood assay.  Both extracts showed their low hemolytic activities (about 5-13%) for the concentration of 100 and 150 μg/mL, but the activity increased sharply (about 96%) on the concentration of 200 μg/mL.  It was concluded that C. lentillifera has a potency as a functional food due to containing secondary metabolites with various biological activities.

Minyak dan lemak termasuk dalam kategori limbah organik yang dapat mencemari lingkungan. Grease trap dapat memisahkan minyak dan lemak dari limbah, sehingga tidak menggumpal dan membeku yang dapat membuat pipa tersumbat. Pada penelitian ini, grease trap  dimodifikasi dengan karbon aktif. Penelitian ini bertujuan untuk mengkaji efisiensi penggunaan grease trap yang dimodifikasi dengan karbon aktif untuk mereduksi minyak, lemak dan bahan organik dari limbah rumah makan. Penelitian ini dimulai dari preparasi karbon aktif, kemudian dilanjutkan ke tahapan persiapan alat, optimasi alat dan uji kinerja alat grease trap  termodifikasi karbon aktif. Berdasarkan hasil pengujian, air limbah hasil output dari grease trap mengandung 1217,6 mg/L COD; 645 mg/L BOD; 156 mg/L TSS; dan 88,45 mg/L minyak dan lemak. Kandungan air limbah hasil output grease trap yang dimodifikasi dengan kolom sepanjang 10 cm yang berisi karbon aktif adalah COD 2,5 mg/L; BOD 19 mg/L; TSS 3,4 mg/L; minyak dan lemak tidak terdeteksi. Penggunaan kolom yang diisi dengan karbon aktif untuk dimodifikasi pada alat grease trap ternyata mampu menurunkan konsentrasi BOD, COD, TSS, minyak dan lemak dari limbah hingga ke nilai baku mutu air limbah bagi usaha dan/atau kegiatan domestik.

The bandgap energy (Egap) of TiO2 material modified with metal-chlorophyll complex compounds (M = Cu2+, Fe3+) was observed. Chlorophyll (Chl) was isolated from cassava leaves, and its UV-Vis spectra showed absorption peaks in the Soret band region (410 nm) and in the Q band region (665 nm), which is the typical peak of chlorophyll. Copper(II)-chlorophyll complex was prepared from the reaction between chlorophyll and CuSO4.5H2O, while the iron(III)-chlorophyll was synthesized from chlorophyll and FeCl3.6H2O in methanol solvent under reflux at 65°C. The presence of copperand iron metals in the chlorophyll metal complexes was identified using Atomic Absorption Spectroscopy in methanol solution. The absorption of copper measured in Cu2+-Chl was 0.0488 (0.4805 mg/L), while the iron atom in Fe3+-Chl was 0.0050 (0.0195 mg/L). The UV-vis spectra demonstrate the hypsochromic shift of the Soret band to 405 nm (Cu2+-Chl) and 402 nm (Fe3+-Chl). The Infrared spectra of chlorophyll after being complexed with copper(II) shows the increase of vibrational absorption wavenumber of the C=N group from 1225.06 cm-1 to 1241.94 cm-1 indicates the coordination of the metal ion on the N atom in the pyrrole ring. The shift in the absorption band on the Fe3+-Chl spectrum was seen for the C=O ester group from 1720.49 cm-1 to 1721.10 cm-1 indicating the metal ion bonding in the C=O group of esters. The DR-UVis analysis of TiO2/metal-chlorophyll shows a bathochromic shift towards the visible light region. By using the Tauc plot method, it was observed that the Egap of TiO2 reduces from 3.08 eV to 2.89 eV and 2.93 eV in the compound of TiO2/Cu2+-Chl and TiO2/Fe3+-Chl, respectively.

Sungai Ringin power plant located in Kedabang Village, Sintang District of Indonesia, uses coal as its main source of energy. Chemically, coal combustion products are volatile materials, such as CO2, SO2, NO2 and H2O and non-volatile materials in the form of coal ash known as bottom ash and fly ash. During the process of coal combustion, a portion of the mineral fuses into fly ash particles, which can form crystalline phases like quartz and mullites, though the glass phase covers the aluminosilicate surface. This potentially creates detrimental impact on the environment [1]. Therefore, the problem of coal fly ash should be solved by utilizing wasted materials in order to avoid their accumulation in large amounts. Fly ash contains metal oxides with main components of SiO2 and Al2O3 with several crystal forms, such as quartz (SiO2), mullite (2SiO2.3Al2O3), hematite (α-Fe2O3) and magnetite (Fe3O4) [1]. The fly ash containing more than 85 % of SiO2 and Al2O3 can be used as a raw material of sodium silicate and synthetic aluminate [2]. A new approach widely developed for the utilization of fly ash is converting it into value-added products as zeolites [2-4]. The X-ray fluorescence (XRF) analysis shows that Sungai Ringin's fly ash contains minerals of SiO2 (about 53.26 %) and Al2O3 (about 28.13 %). So, it is reasonable to utilize it for synthesizing zeolite materials. The components of SiO2 and Al2O3 are the active side of fly ash and bottom ash, which can be used as zeolite base for removing heavy metals, phenol wastes and dye waste in waters.

Secang (Caesalpinia sappan Linn) merupakan tanaman endemik Kalimantan Barat yang mengandung pigmen berwarna merah brazilin. Dalam penelitian ini, brazilin diperoleh melalui proses maserasi dilanjutkan dengan partisi cair-cair, selanjutnya dikomplekskan dengan ion logam Cu, Mg, dan Zn untuk meningkatkan kinerjanya ketika digunakan sebagai sensitizer pada dye sensitized solar cell (DSSC). Pengompleksan dilakukan menggunakan media gliserol-air, sedangkan fabrikasi DSSC dilakukan menggunakan metode doctor blading. Hasil analisis FTIR terhadap ekstrak kayu secang menunjukkan adanya gugus fungsi O-H, C=O, C=C, dan C-H, yang merupakan gugus fungsional khas dari brazilin. Terbentuknya kompleks brazilin-Cu, brazilin-Mg, dan brazilin-Zn ditandai dengan menurunnya intensitas puncak dari C=O pada 1606 cm-1 dan –OH pada 3263 cm-1. Hasil analisis UV-Vis menunjukkan bahwa kompleks memiliki rentang panjang gelombang lebih lebar dan cenderung batokromik. DSSC yang menggunakan kompleks brazilin-Cu, brazilin-Mg, dan brazilin-Zn menghasilkan rendemen konversi energi maksimum pada 200 W/m2, berturut-turut sebesar 0.034 %, 0.030 %, dan 0.013 %, serta DSSC ekstrak kayu secang murni sebesar 0.029 %. Dengan demikian, penggunaan sensitizer berbasis kompleks logam-brazilin dapat meningkatkan efisiensi DSSC. Kata kunci: Brazilin, DSSC, fotosensitizer, kayu secang, kompleks. Secang (Caesalpinia sappan Linn) is an endemic plant in West Kalimantan that contains Brazilin red pigments. In this study, brazilin was obtained through a maceration process carried out by a liquid-liquid partition, then complexed with metal ions to improve the performance of compilation used as a sensitizer on dye-sensitized solar cell (DSSC). Complexation is carried out using glycerol-water media, while DSSC fabrication is carried out using the doctor blading method. The results of FTIR analysis of secang wood extract showed the presence of a functional group O-H,  C=O, C=C, and C-H, which are typical functional groups of brazilin. The formation of the brazilin-Cu, brazilin-Mg, and brazilin-Zn complexes is characterized by an increase in peak intensity of  C=O at 1606 cm-1 and O-H at 3263 cm-1. The results of the UV-Vis analysis show that the complex has a wider wavelength and uses batochromic. DSSCs that use the brazilin-Cu, brazilin-Mg, and brazilin-Zn complexes that complement each other produce efficiencies of  0.034%, 0.030%, and 0.013%, and DSSC pure secang wood extract of  0.029%. The efficiency of the brazilian metal-complex when compared with brazilin, the efficiency increases, so that the maximum efficiency obtained by the Cu-brazilin sensitizer is equal to 0.034%. Keywords: Brazilin, DSSC, photosensitizer, secang wood, complex.

<p>Telah dilakukan optimasi dan validasi metode penentuan asam glikolat dan asam laktat dalam krim menggunakan kromatografi cair kinerja tinggi. Pemisahan asam glikolat dan asam laktat dilakukan pada kolom fasa balik C-8menggunakan fasa gerak asam ortofosfat 0,1% dengan pH 3,5 dan detektor <em>UV-Visible</em>. Standar asam glikolat dan asam laktat dibuat dengan melarutkannya menggunakan asam ortofosfat 0,1% pH 3,5. Hasil eksperimen menunjukkan bahwa pada rentang konsentrasi 25 – 400 μg/mL, asam glikolat dan asam laktat memiliki kurva yang linear dengan koefisien korelasi masing-masing 0,9997 dan 0,9999. Uji presisi untuk larutan standar berkonsentrasi 100 µg/mL menghasilkan simpangan baku relatif sebesar 1,49% untuk asam glikolat dan 1,72% untuk asam laktat. Metode yang telah dioptimasi memberikan akurasi yang baik yang ditunjukkan oleh nilai perolehan kembali dari pengukuran tiga <em>spiked sample</em> dengan konsentrasi berbeda (50, 100, dan 150 μg/mL). Nilai perolehan kembali untuk masing-masing konsentrasi <em>spiked sample</em> adalah 97,12% ± 0,69; 98,76% ± 0,43; 100,80% ± 0,29 untuk asam glikolat dan 97,58% ± 0,39; 96,20% ± 0,68; 98,00% ± 0,38 untuk asam laktat. Batas deteksi dan batas kuantisasi untuk asam glikolat adalah 0,05 dan 0,17 μg/mL, sedangkan untuk asam laktat adalah 1,40 dan 4,67 μg/mL. Nilai kekasaran metode untuk asam glikolat pada hari pertama dan hari kedua adalah 1,43% dan 1,67%, sedangkan untuk asam laktat adalah 1,67% dan 1,25%. Metode yang telah dioptimasi dan divalidasi berpotensi untuk digunakan secara spesifik pada penentuan kadar asam glikolat dan asam laktat dalam krim.</p><p><strong>Optimization and Validation of Determination Methods of Glycolic Acid and Lactic Acid in Cream Using High-Performance Liquid Chromatography.</strong> A high-performance liquid chromatography analytical method for the determination of glycolic acid and lactic acid in creams has been optimized and validated. The separation was performed in a reverse phase C–8 column with a mobile phase of 0.1%, orthophosphoric acid at pH 3.5, and UV-Visible detector. The standard of glycolic acid and lactic acid was dissolved in 0.1% orthophosphoric acid at pH 3.5. The experimental results showed that in the concentration range of 25–400 μg/mL, glycolic acid and lactic acid showed a linear curve with a correlation coefficient of 0.9997 and 0.9999, respectively. The precision test for standard solutions containing 100 µg/mL resulted in a relative standard deviation of 1.49% for glycolic acid and 1.72% for lactic acid. The optimized method provided good accuracy indicated by the recovery of the measurement of three spiked samples in different concentrations (50, 100, and 150 μg/mL). The recovery for each concentration of the spiked sample was 97.12% ± 0.69; 98.76% ± 0.43; 100.80% ± 0.29 for glycolic acid and 97.58% ± 0.39; 96.20% ± 0.68; 98.00% ± 0.38 for lactic acid. The limit of detection and limit of quantization for glycolic acid was 0.05 and 0.17 μg/mL, and for lactic acid was 1.40 and 4.67 μg/mL. The ruggedness of the method for glycolic acid on the first day and second day was 1.43% and 1.67%, while for lactic acid, it was 1.67% and 1.25%. The method that has been optimized and validated shows the potential to be used specifically for the determination of glycolic acid and lactic acid in the cream.</p>

Iron sand is obtained from one of the waste treatments stages of bauxite residue called red mud, operated at PT. Indonesia Chemical Alumina (PT. ICA). Preliminary analysis of the sand indicates that the main element contained in the sand is iron with a percentage of up to 60% and titanium at 10%. This study aims to determine the elemental composition and mineral characteristics of sand that was separated magnetically from the iron sand. Magnetic separation was carried out in two stages, namely separation using a weak magnets and strong magnets. The separation resulted in approximately 71% of strong magnetic sand. The rest was separated using the strong magnet giving almost 70% of weak magnetic sand while the residue is non-magnetic sand. The weak magnetic sand was analyzed using XRF and XRD to determine elemental composition as well as the type of mineral contained in the material. Elemental analysis showed that the weak magnetic sand contains 66.331% of iron, 13,120% of silicone, 9.216% of aluminum and 7.040% of titanium. The XRD analysis presented that crystalline phase in the sand consists of ilmenite, hematite, goethite, quartz and rutile.

Red mud or commonly called bauxite residue is solid waste generated from the purification of bauxite into alumina through the Bayer process. The red mud was initially dried under the sun then was magnetically separated to give magnetic sand. The magnetic sand was neutralized using copious of water, refined and then characterized using XRF and XRD methods. The results show that the main elements contained in the magnetic sand from the red mud are silicon, aluminum, iron, titanium, and magnesium. XRD analysis using Search-Match followed by the calculation using Rietveld refinement showed that the sand consisted of ferrosillite (55.3%), hematite (33.9%) and ilmenite (10.7%). Elemental analysis using XRF showed the percentage of Fe 29.15%, Si 22.49%, Ca 3.19%, and Ti 2.92%, followed by other elements with low percentages.