Judul: Biodegradasi Fenol Limbah Cair Industri Tekstil oleh Candida tropicalis
Abstrak: Large quantities of textile waste were produced during the operation of textile industry. It materials contained a high level of phenol compounds that results a serious environmental problem. One of microorganism that used phenol for carbon source is Candida tropicalis. In this studi, Candida tropicalis was used in an aerobic biodegradation process to reduce phenol concentration in order to optimum condition. Phenol concentration was determined by 4-aminoantipyrine method on 510 nm. Results showed that degradation rate is optimum at 30oC and a pH of 6. Phenol concentration in control not decrease during observation, meanwhile textile wastewater that inoculation Candida tropicalis decrease 30% for 6 hours with degradation rate 0.025 mg L-1 h-1. This degradation rate is lower than in pure phenol 12.5 mg L-1 h-1. The other results show that phenol disposed to degraded than to produce cell biomass that showing optical density of cell biomass is constant during observation.
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Judul: Penentuan Kondisi Optimum pada Proses Fenton dalam Pengolahan Limbah Tekstil
Abstrak: Textile waste from the textile industry activity increases with the textile industry activities. Textile waste has relatively high biochemical oxygen demand (BOD), color, total suspended solids (TSS), electrical conductivity, and zinc content. Therefore, waste treatment is needed. One of the waste treatments is Fenton process using Fenton reagent that is hydrogen peroxide (H2O2) and ferrous sulfate (FeSO4). Fenton reagent can oxidize and degrade organic compounds. In this study, textile waste was tested based on the influence of pH, concentration of hydrogen peroxide, and the concentration of ferrous sulfate. The largest decrease occurred in the BOD under pH 5 in combination with H2O2 concentration of 25 mg/L and the concentration of FeSO4 50 mg/L. Beside that, this combination showed significant reduction of the three other parameters, namely TSS, electrical conductivity, and zinc content.
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Judul: Determinan dan Invers Matriks Leslie Ganda dengan Formula Schur
Abstrak: Matriks Leslie ganda merupakan bentuk umum dari matriks Leslie, matriks companion, dan matriks companion ganda. Bentuk khusus komplemen Schur dapat digunakan pada formula Schur untuk mendapatkan rumus determinan dan invers. Tujuan dari penulisan karya ilmiah ini adalah mengkaji secara teoritis pembuktian formulasi determinan dan invers matriks Leslie ganda berdasarkan formula Schur. Pembuktian formula determinan dan invers matriks Leslie ganda dilakukan dengan mensubstitusi formula determinan dan invers matriks persegi menggunakan komplemen Schur., The doubly Leslie matrix is generalized of the Leslie matrix, the double companion matrix, and the companion matrix. The unique form of Schur complement can be used in Schur’s formula to obtain a formula of the determinant and inverse of doubly Leslie matrix. In this article, the proof of those formulation are discussed theoretically based on Schur’s formula. Proof of the determinant and inverse formulation perform by substitute the determinant and inverse of square matrix with Schur Complement.
Keyword: Komplemen Schur, Formula Schur, Determinan, Invers, Matriks Leslie Ganda