Green Production of Zero-Valent Iron (ZVI) Using Tea-Leaf Extracts for Fenton Degradation of Mixed Rhodamine B and Methyl Orange Dyes.

Diana Rakhmawaty Eddy,Iman Rahayu,Solihudin Solihudin,Atiek Rostika Noviyanti,Dian Nursyamsiah,Muhamad Diki Permana

doi:10.3390/ma15010332

Abstract

The danger from the content of dyes produced by textile-industry waste can cause environmental degradation when not appropriately treated. However, existing waste-treatment methods have not been effective in degrading dyes in textile waste. Zero-valent iron (ZVI), which has been widely used for wastewater treatment, needs to be developed to acquire effective green production. Tea (Camellia sinensis) leaves contain many polyphenolic compounds used as natural reducing agents. Therefore, this study aims to synthesize ZVI using biological reducing agents from tea-leaf extract and apply the Fenton method to degrade the color mixture of rhodamine B and methyl orange. The results show that the highest polyphenols were obtained from tea extract by heating to 90 °C for 80 min. Furthermore, PSA results show that ZVI had a homogeneous size of iron and tea extract at a volume ratio of 1:3. The SEM-EDS results show that all samples had agglomerated particles. The ZVI 1:1 showed the best results, with a 100% decrease in the color intensity of the dye mixture for 60 min of reaction and a degradation percentage of 100% and 66.47% for rhodamine B and methyl orange from LC-MS analysis, respectively. Finally, the decrease in COD value by ZVI was 92.11%, higher than the 47.36% decrease obtained using Fe(II).

Highlights

The textile industry is one of the fastest-growing sectors in Indonesia, and according to data from the Indonesian Ministry of Industry, it grew by 15.08% in 2019 [1]
103965, Kenilworth, NJ, USA,), Folin Ciocalteu reagent, which is a mixture of phosphomolybdate and phosphotungstate (2 mol/L, Merck 109001, Kenilworth, NJ, USA), sodium carbonate (Na2 CO3, 99.9%, Merck 106392, Kenilworth, NJ, USA), gallic acid (C7 H6 O5, 98%, Merck 842649, Kenilworth, NJ, USA), tea leaves (Camellia sinensis) from the Citengah tea plantation, Sumedang, Indonesia (Figure S1), concentrated sulfuric acid (H2 SO4, 95–97%, Smart Lab A-1092 F), hydrogen peroxide (H2 O2, 30%, Merck 107209, Kenilworth, NJ, USA), digestion solution for chemical oxygen demand (COD) (prepared from mercury(II) sulfate (HgSO4, 98%, Merck 104480, Kenilworth, NJ, USA) and potassium dichromate
The results show that the optimum dose of Zero-valent iron (ZVI) to reduce the color intensity of the rhodamine B and methyl orange mixture was ZVI 1:1 150 mg/L

Summary

Introduction

The textile industry is one of the fastest-growing sectors in Indonesia, and according to data from the Indonesian Ministry of Industry, it grew by 15.08% in 2019 [1]. The number of textile industry activities is directly proportional to the amount of wastewater generated. Effective and environmentally friendly treatment of industrial wastewater, especially dye waste, is needed. The commonly used methods in wastewater treatment to reduce dye content include adsorption, coagulation, and flocculation methods [4,5,6,7]. Using these methods to minimize dyestuffs is often not perfect because it requires a large amount of coagulant. The regeneration process is complex, the cost is high, and the sludge generated from treatment residue is significant [10,11,12]. Modifications to existing water-treatment methods are needed

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Conclusion