International Journal of Advances in Applied Sciences (IJAAS) Vol. 14, No. 1, March 2025, pp. 255~267 ISSN: 2252-8814, DOI: 10.11591/ijaas.v14.i1.pp255-267  255 Journal homepage: http://ijaas.iaescore.com Bio-adsorbents from banana peel and corncob in reducing Naphthol Yellow S dye Iva Rustanti Eri, Marlik Marlik, Khambali Khambali Department of Environmental Health, Faculty of Health Science, Poltekkes Kemenkes Surabaya, Surabaya, Indonesia Article Info ABSTRACT Article history: Received Jul 7, 2024 Revised Jan 19, 2025 Accepted Jan 26, 2025 Naphthol Yellow S, a textile dye waste, poses environmental pollution due to its degradable chromophore and auxochrome groups, necessitating processing. The aim was to analyze the adsorption kinetics of banana peel and corncob bioadsorbents to reduce the dye Naphthol Yellow S in wastewater. This research was a true experiment and the object used was an artificial Naphthol Yellow S solution with an initial concentration of 80 ppm applied to the adsorbent mass of 0.1, 0.2, and 0.3 grams and contact time of 3, 6, 9, and 12 hours. Dye levels were measured before and after treatment using a spectrophotometer. The best adsorption test occurred on the banana peel bioadsorbent with an adsorbent mass of 0.3 grams and a stirring time of 3 hours. The adsorption study of banana peel and corncob bioadsorbents showed that the entire adsorption process of Naphthol Yellow S dye followed the Langmuir isothermal adsorption model with R 2 coefficients of 0.9953 and 0.999, respectively, and maximum adsorption capacities of 4.6516 and 5.2825 mg/g, respectively. The activated carbon adsorption kinetics followed the second order, with R 2 values of 0.9737 and 0.9152, respectively. This study concluded that the bioadsorbent of banana peels and corncob was able to reduce the dye Naphthol Yellow S. Keywords: Banana peel Bio adsorbent Corncob Dye Naphthol Yellow S This is an open access article under the CC BY-SA license. Corresponding Author: Iva Rustanti Eri Department of Environmental Health, Faculty of Health Science, Poltekkes Kemenkes Surabaya Surabaya, East Java, Indonesia Email: ivakesling@gmail.com 1. INTRODUCTION Water is the most essential raw element for humans, animals, plants, and microbes, water is the most essential raw element [1]. Almost every important biotic phenomenon is dependent on water availability. Today's society faces a significant water pollution issue because of the rapid advancement of technology [2]. Ecosystems deteriorate when untreated or insufficiently treated residential, industrial, and agricultural wastewater is released [3]. Given that industrial effluents have a far more hazardous nature, this issue is even more serious [4]. Tanneries and the textile sector ranked first and second, respectively, among industries that use large amounts of water [5]. Particularly significant are the textile printing and finishing industries as well as the dyeing sector [6]. Wastewater, which is heavily laden with basic or acidic dyes, salts, and adjuvants, is significantly polluted by these processes [7]. Considerable research has been conducted on the disposal of these dyes, including precipitation [8], ionic exchange [9], membrane filtration [10], electrochemical destruction [11], photodegradation [12], and adsorption [13]. Because of its many adsorbents, ease of design, high efficiency, and capacity to treat dyes in a more concentrated form, adsorption is regarded as a superior technique among these procedures when compared to other treatment methods [14].