WAKTU KONTAK OPTIMUM ARANG AKTIF KULIT JAMBU METE DALAM MENURUNKAN KADAR COD PADA LIMBAH LAUNDRY - Lasmi Astuti; Dahlan Dahlan; Ekacahyana Mandasari (CENDEKIA: Jurnal Ilmu Pengetahuan, 2026)
The increasing use of laundry services has led to a higher volume of liquid waste produced, which has the potential to pollute aquatic environments. Laundry waste contains detergents, surfactants, oils, fats, and organic compounds that can increase the Chemical Oxygen Demand (COD) value. A high COD value indicates a high content of organic matter in the waste, making treatment necessary before disposal into the environment. This study aims to determine the ability of cashew nut shell activated carbon to reduce the COD levels in laundry waste and to determine the optimum contact time for the adsorption process. The activated carbon was produced through the carbonization process of cashew nut shells at temperatures of 300–500°C and chemically activated using a 0.4 M HCl solution. The study was conducted using the adsorption method with 2 grams of adsorbent in 100 mL of laundry waste at contact times of 15, 30, 45, 60, and 75 minutes. COD levels were analyzed using the closed reflux method by titrimetry based on SNI 6989.15:2019. The results of the study showed that the initial COD level of laundry waste was 2320 mg/L. Adsorption using cashew shell activated carbon was able to reduce COD levels at all contact time variations compared to the initial sample. The greatest reduction was obtained at a contact time of 15 minutes with a COD level of 880 mg/L and a reduction efficiency of 62.07%. At longer contact times, the adsorption efficiency tended to decrease due to the reduction of active sites on the adsorbent and the occurrence of desorption processes. Based on the results of the study, it can be concluded that cashew shell activated carbon has the potential to be used as an adsorbent to reduce COD levels in laundry waste, with an optimum contact time of 15 minutes. ABSTRAK Meningkatnya penggunaan jasa laundry menyebabkan volume limbah cair yang dihasilkan semakin tinggi dan berpotensi mencemari lingkungan perairan. Limbah laundry mengandung deterjen, surfaktan, minyak, lemak, dan senyawa organik yang dapat meningkatkan nilai Chemical Oxygen Demand (COD). Tingginya nilai COD menunjukkan tingginya kandungan bahan organik dalam limbah sehingga diperlukan pengolahan sebelum dibuang ke lingkungan. Penelitian ini bertujuan untuk mengetahui kemampuan arang aktif kulit jambu mete dalam menurunkan kadar COD limbah laundry serta menentukan waktu kontak optimum proses adsorpsi. Arang aktif dibuat melalui proses karbonisasi kulit jambu mete pada suhu 300–500°C dan diaktivasi secara kimia menggunakan larutan HCl 0,4 M. Penelitian dilakukan dengan metode adsorpsi menggunakan 2 gram adsorben dalam 100 mL limbah laundry pada variasi waktu kontak 15, 30, 45, 60, dan 75 menit. Kadar COD dianalisis menggunakan metode refluks tertutup secara titrimetri berdasarkan SNI 6989.15:2019. Hasil penelitian menunjukkan bahwa kadar COD awal limbah laundry sebesar 2320 mg/L. Adsorpsi menggunakan arang aktif kulit jambu mete mampu menurunkan kadar COD pada seluruh variasi waktu kontak dibandingkan sampel awal. Penurunan terbesar diperoleh pada waktu kontak 15 menit dengan kadar COD sebesar 880 mg/L dan efisiensi penurunan sebesar 62,07%. Pada waktu kontak yang lebih lama, efisiensi adsorpsi cenderung menurun akibat berkurangnya situs aktif adsorben dan terjadinya proses desorpsi. Berdasarkan hasil penelitian dapat disimpulkan bahwa arang aktif kulit jambu mete berpotensi digunakan sebagai adsorben untuk menurunkan kadar COD limbah laundry, dengan waktu kontak optimum selama 15 menit.