Mango Peel Extract as a Biocoagulant for Tofu Wastewater: Effects of HNO3 and Temperature

Authors

  • Gimaya Dias Sarah Department of Chemical Engineering, D4 Industrial Chemical Technology Program, Sriwijaya State Polytechnic, Jl. Srijaya Negara, Bukit Besar, Ilir Barat I District, Palembang City, South Sumatra 30139, Indonesia
  • Erika Dwi Oktaviani Department of Chemical Engineering, D4 Industrial Chemical Technology Program, Sriwijaya State Polytechnic, Jl. Srijaya Negara, Bukit Besar, Ilir Barat I District, Palembang City, South Sumatra 30139, Indonesia
  • Dilia Puspa Department of Chemical Engineering, D4 Industrial Chemical Technology Program, Sriwijaya State Polytechnic, Jl. Srijaya Negara, Bukit Besar, Ilir Barat I District, Palembang City, South Sumatra 30139, Indonesia

DOI:

https://doi.org/10.33394/hjkk.v14i5.22720

Keywords:

Biocoagulant, Mango Peel, Solid-Liquid Extraction, Tofu Wastewater, Coagulation-Flocculation

Abstract

Tofu industry wastewater contains high levels of BOD, COD, and TSS, posing a significant risk of environmental pollution. Synthetic chemical coagulants have limitations, such as lowering the pH of treated water and posing health risks. This study aims to utilize mango peel (Mangifera indica L.) extract as a natural biocoagulant in tofu wastewater treatment. A crude mango peel extract was obtained from mango peel powder by reflux extraction using HNO₃ at various concentrations (0.10; 0.15; 0.20; 0.25; 0.30 N) and temperatures (65, 70, 75, 80 °C) for 2 h. The extract was applied to filtered tofu wastewater at a tested dose of 200 mg/L. A control treatment (without extract) was subjected to identical mixing and settling. Extract yield and wastewater parameters (turbidity, TSS, COD, BOD, and pH) were analyzed. The highest extract yield was obtained at 0.20 N HNO₃ and 70 °C, reaching 18.2%. The control showed no reduction in pollutant levels, indicating that physical processes alone were insufficient. The best-performing treatment among the tested conditions was obtained at 0.20 N HNO₃ and 75 °C, which reduced TSS from 980 to 200 mg/L (79.59%), COD from 543 to 290 mg/L (46.59%), BOD from 180.3 to 94 mg/L (47.86%), and turbidity from 425 to 62 NTU (85.41%) relative to the control. COD and BOD met the quality standards of Indonesian Ministry of Environment Regulation No. 5 of 2014, while TSS reached the maximum limit. However, the final pH of 5.60 remained below the standard range of 6–9. This study indicates that mango peel extract has potential as a natural biocoagulant, although a further pH neutralization stage is needed.

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Published

2026-10-31

How to Cite

Sarah, G. D., Oktaviani, E. D., & Puspa, D. (2026). Mango Peel Extract as a Biocoagulant for Tofu Wastewater: Effects of HNO3 and Temperature. Hydrogen: Jurnal Kependidikan Kimia, 14(5). https://doi.org/10.33394/hjkk.v14i5.22720

Issue

Vol. 14 No. 5 (2026): October 2026

Section

Articles

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Copyright (c) 2026 Gimaya Dias Sarah, Erika Dwi Oktaviani, Dilia Puspa

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