Asih, I. A. R. A.
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DEGRADASI ZAT WARNA CONGO RED DENGAN FOTOKATALIS ZnO-ARANG AKTIF DAN OKSIDATOR H2O2 Abimanyu, A. A.; Suprihatin, I. E.; Asih, I. A. R. A.
Jurnal Kimia (Journal of Chemistry) Vol. 18, No.2, Juli 2024
Publisher : Program Studi Kimia, FMIPA, Universitas Udayana (Program of Study in Chemistry, Faculty of Mathematics and Natural Sciences, Udayana University), Bali, Indonesia

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Abstract

Industri tekstil adalah salah satu kontributor utama limbah cair yang mengandung berbagai zat warna sintetis yang sulit untuk diuraikan, seperti Congo red, yang berpotensi merusak ekosistem perairan. Untuk mengatasi permasalahan ini, pendekomposisian zat warna tersebut dilakukan menggunakan sinar UV dan dipercepat melalui bantuan fotokatalis, yaitu ZnO-Arang Aktif. Penelitian ini bertujuan untuk menentukan kondisi optimum, seperti pH, massa, dan waktu iradiasi dalam proses degradasi Congo red, serta menganalisis pengaruh penambahan oksidator H2O2 terhadap efektivitas ZnO-AA dalam proses degradasi tersebut. Aktivitas fotokatalitik diukur dengan menghitung persentase degradasi larutan Congo red menggunakan spektrofotometri UV-Vis. Hasil penelitian menunjukkan bahwa kondisi optimum degradasi Congo red terjadi pada massa fotokatalis sebanyak 60 mg, penambahan H2O2 sebanyak 0,5 mL, pH 5, dan waktu iradiasi selama 60 menit, dengan persentase degradasi sebesar 97,99 ± 0,06%. Efektivitas degradasi Congo red juga diuji pada berbagai konsentrasi pada kondisi optimum, dan hasil percobaan menunjukkan bahwa kombinasi fotokatalis ZnO-AA dengan penambahan oksidator H2O2 mampu mendegradasi zat warna Congo red hingga konsentrasi 300 mg/L, dengan persentase degradasi sebesar 99,08 ± 0,01%. Kata kunci: congo red, degradasi, fotokatalis, H2O2, ZnO-AA. ABSTRACT The textile industry is one of the major contributors to wastewater containing various synthetic dyes that are difficult to degrade, such as congo red, which can harm aquatic ecosystems. To address this issue, the decomposition of these dyes is carried out using UV light and accelerated with the assistance of a photocatalyst, namely ZnO-Activated Carbon (ZnO-AA). This study aims to determine the optimum conditions, including pH, mass, and irradiation time in the degradation of congo red, and to analyze the influence of adding H2O2 oxidizer in enhancing the effectiveness of ZnO-AA in the degradation process. The photocatalytic activity is measured by measuring the percentage degradation of congo red solution using UV-Vis spectrophotometry. The research results indicate that the optimum conditions for degrading congo red are achieved with a photocatalyst mass of 60 mg, the addition of 0.5 mL H2O2, pH 5, and an irradiation time of 60 minutes, resulting in a degradation percentage of 97.99 ± 0.06%. The effectiveness of congo red degradation was also tested at various concentrations under optimum conditions, and the experimental results show that the combination of ZnO-AA photocatalyst with the addition of H2O2 oxidizer can degrade congo red dye up to a concentration of 300 mg/L, with a degradation percentage of 99.08 ± 0.01%. Keywords: congo red, degradation, H2O2, photocatalyst, ZnO-AC.
EFEKTIVITAS INHIBITOR KOROSI DARI EKSTRAK DAUN JERUK LEMON (Citrus limon L.) PADA BAJA ST-37 DALAM MEDIA NaCl DAN HCl Cahyanti, N. N. A. T.; Asih, I. A. R. A.; Widihati, I. A. G.
Jurnal Kimia (Journal of Chemistry) Vol. 18, No.2, Juli 2024
Publisher : Program Studi Kimia, FMIPA, Universitas Udayana (Program of Study in Chemistry, Faculty of Mathematics and Natural Sciences, Udayana University), Bali, Indonesia

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Abstract

ABSTRAK Korosi merupakan fenomena alam yang dapat merusak material logam seperti baja St-37 dan juga menyebabkan degradasi struktur serta penurunan kinerja material logam. Beberapa penelitian telah dilakukan untuk mengembangkan inhibitor korosi sebagai solusi yang efektif. Salah satu bahan alam yang digunakan sebagai inhibitor korosi adalah ekstrak daun lemon, yaitu senyawa kimia yang ditambahkan ke lingkungan korosif untuk menghambat atau mencegah reaksi oksidasi logam. Penelitian ini bertujuan untuk mengetahui laju korosi baja St-37 dalam media korosif NaCl dan HCl serta efisiensi inhibisi penggunaan inhibitor ekstrak daun lemon dengan berbagai konsentrasi untuk mencegah korosi. Daun lemon diekstraksi menggunakan metode maserasi, kemudian ekstrak tersebut diuji kandungan metabolit sekundernya. Laju korosi ditentukan menggunakan metode kehilangan berat. Hasil uji fitokimia menunjukkan bahwa ekstrak daun lemon positif mengandung alkaloid, fenol, flavonoid, tanin, dan tanin terkondensasi. Laju korosi terendah baja St-37 pada media korosif NaCl dan HCl masing-masing sebesar 0,1685 dan 0,0658 mmpy (millimetre per year), dan efisiensi inhibibisi tertinggi untuk melindungi media korosif masing-masing sebesar 96,6963 dan 40,3065%, dicapai pada konsentrasi inhibitor 500 ppm. Pengurangan laju korosi dan efisiensi penghambatan oleh ekstrak daun lemon pada baja S-37 dalam media korosif HCl lebih baik daripada dalam media NaCl. Kata kunci: Efisiensi inhibisi, Inhibitor, Korosi, Laju korosi, Lemon ABSTRACT Corrosion is a natural phenomenon that can damage metal materials such as St-37 steel and also causes structural degradation and decreased performance of metal materials. Several studies have been conducted to develop corrosion inhibitors as an effective solution. One of the natural products used as a corrosion inhibitor is lemon leaf extract, a chemical compound added to corrosive environments to inhibit or prevent metal oxidation reactions. This study aimed to determine the corrosion rate of St-37 steel in NaCl and HCl corrosive media and the inhibition efficiency of using lemon leaf extract inhibitors with varying concentrations to prevent corrosion. Lemon leaves were extracted using the maceration method, and then the extract was tested for secondary metabolite content. The corrosion rate was determined using the weight loss method. The results of the phytochemical test showed that lemon leaf extract positively contained alkaloids, phenols, flavonoids, tannins, and condensed tannins. The lowest corrosion rate of the St-37 steel in the NaCl and HCl corrosive media of 0.1685 and 0.0658 mmpy (millimeter per year), respectively, and the highest efficiency of the inhibitor to protect corrosive media of 96.6963 and 40.3065%, respectively, were achieved at the inhibitor concentration of 500 ppm. The corrosion rate reduction and the inhibition efficiency by lemon leaf extract on the S-37 steel in HCl corrosive media was better than in NaCl media. Keywords: Corrosion, Corrosion rate, Inhibition efficiency, Inhibitor, Lemon