Judul: Reaksi Fenton Diikuti Presipitasi oIeh Sulfida sebagai Metode Penanganan Limbah Cair Laboratorium dari Pengujian COD dan Klorida
Abstrak: Limbah cair laboratorium terdiri atas berbagai jenis bahan kimia yang dihasilkan dari sisa analisis kegiatan sehari-bari. Limbah ini di antaranya mengandung pencemar berbahaya dan saat ini belum terdapat pengolahan yang khusus mengatasi masalah ini. Limbah hasil pengukuran COD (chemical oxygen demand) dan limbah hasil pengukuran k10rida diteliti untuk diolah sebagai langkah awal terciptanya pengolahan limbah cair laboratorium yang baik. Kedua limbah ini dipilih karena menggunakan merkuri (Hg) pada proses analisisnya. Merkuri dalam jumlah sedikit saja dapat berbahaya bagi Iingkungan apabila tidak ditangani dengan tepat. Limbah cair seeara umum terdiri atas pencemar organik dan pencemar anorganik. Reaksi Fenton diusulkan untuk mengatasi komponen organik pencemar limbah. Presipitasi oleh sulfida diusulkan untuk mengatasi komponen anorganik pencemar limbah. Pada penelitian ini, pengukuran COD pada limbah hasil pengujian COD menunjukan tidak diperlukannya reaksi Fenton. Pengukuran pada limbah COD hasil pengolahan menunjukan rerata penurunan Ag, Cr, dan Hg berturut-turut sebesar 99,96; 98,63; dan 99,99%. Hasil percobaan memperlihatkan bahwa metode ini mampu mengurangi kadar limbah secara nyata namun masih belum dapat menurunkan kadar pencemar hingga dibawah baku mutu yang ditetapkan. Pengolahan Iimbah klorida memerlukan reaksi Fenton karena kadar COD sampel tinggi. Hasil reaksi Fenton pada Iimbah pengukuran k10rida masih kurang baik karena belum dapat menuruukan kadar COD seeara nyata'
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Judul: Pengolahan limbah cair yang mengandung logam merkuri dengan reaksi Fenton dan presipitasi sulfida
Abstrak: Discharging wastewater to water body can cause environment contamination if its quality does not meet with the corresponding quality standard. For analysis, every laboratory use various hazardous chemicals according to reference methods. This research was intended to reduce environmental contamination by reducing organic matters and metal that exists in wastewater before discharging it to the waters. Wastewater samples were oxidized using Fenton reaction with ratios of 1:10, 1:25, 1:50, and 1:100 (b/b) to reduce its organic matters level and continued by sulfide precipitation using Na2S 13% (b/v) with volumes of 7, 9, 10, 11, 15, and 20 mL in 100 mL samples to reduce its metal content level. The content of organic matters was measured by chemical oxygen demand analysis and for its metal level contents was analyzed using atomic absorption spectroscopy. The highest percentage removal of organic matter level was 92.01% from the ratio of 1:100 and for inorganic compounds reached 99.99% in various Na2S volume. The results indicated that this method could reduce organic matters and metal content level.
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Judul: Penggunaan Teorema Homeomorphy 2-Manifold dan Teorema Euler Poincare pada Torus 𝑇�� dan Simplicial Complex 𝐾��
Abstrak: Two dimensional topological spaces are said to be homeomorphic if they have the same topological invariant, where one of topological invariant used is an Euler characteristic. Homeomorphy 2-Manifold’s Theorem and Euler Poincare’s Theorem are used to distinguish two topological spaces. Homeomorphy 2-Manifold’s Theorem uses Euler characteristic to identify two dimensional topological spaces. Euler Poincare’s Theorem is an alternative way to find Euler characteristic with Betti number, which is topological invariant as well. The objective of this paper is to investigate the homeomorphism of torus 𝑇����� and simplicial complex 𝐾�����. Topological space torus and simplicial complex 𝐾����� have the same Euler characteristic, which is two. Based on Homeomorphy 2-Manifold’s Theorem topological space torus 𝑇����� and simplicial complex 𝐾����� is homeomorphic.
Keyword: simplicial, torus, Euler, homeomorphism, topology