DEGRADASI SURFAKTAN ANIONIK DALAM AIR LIMBAH LAUNDRY DENGAN METODE FOTO-FENTON TERMODIFIKASI ASAM ASKORBAT SEBAGAI SENYAWA PENGKELAT

MARIA A KUTU WOA, Prof. Dr. Endang Tri Wahyuni,MS; Dr.rer.nat Nurul Hidayat Aprilita, S.Si.,M.Si

2023 | Tesis | MAGISTER KIMIA

Telah dilakukan kajian proses degradasi surfaktan anionik dodesil benzena sulfonat (DBS) dalam air limbah laundry menggunakan metode foto-Fenton termodifikasi asam askorbat sebagai senyawa pengkelat. Penambahan asam askorbat dilakukan untuk meningkatkan efektivitas degradasi DBS dalam air limbah laundry pada pH mendekati netral. Proses foto-Fenton dilakukan dengan cara mereaksikan air limbah laundry dengan pereaksi Fenton (Fe2+/H2O2), sinar UV, dan asam askorbat. Dalam proses foto-Fenton tersebut dipelajari pengaruh konsentrasi asam askorbat, pH dan waktu penyinaran UV. Penentuan konsentrasi surfaktan anionik dodesil benzena sulfonat (DBS) dilakukan dengan spektrofotometer UV/Visibel menggunakan pereaksi metilen biru. Hasil penelitian menunjukkan sampel air limbah laundry yang diuji mengandung surfaktan anionik DBS, sebesar 154,98 mg L-1. Proses foto-Fenton dilakukan pada pH netral dengan mereaksikan 20 mL air limbah laundry dengan pereaksi Fe2+ 5 mM, H2O2 50 mM, asam askorbat 9 mM, waktu radiasi UV 60 menit, mampu menurunkan konsentrasi DBS secara maksimal hingga 98,66%. Hasil studi kinetika menunjukkan bahwa reaksi degradasi DBS melalui proses foto-Fenton termodifikasi asam askorbat mengikuti reaksi orde dua dengan nilai konstanta laju reaksi 0,0025 L mg-1 menit-1. Proses foto-Fenton pada kondisi optimum dapat menurunkan konsentrasi DBS dalam air limbah laundry sebesar 129,74 mg L-1 menjadi 1,728 mg L-1 yang telah memenuhi baku mutu air limbah laundry yaitu 5 mg L-1, sehingga air limbah laundry dapat dibuang ke lingkungan.

The degradation process of anionic surfactant dodecyl benzene sulfonate (DBS) in laundry wastewater using the photo-Fenton method modified with ascorbic acid as a chelating agent has been studied. The addition of ascorbic acid aims to increase the effectiveness of DBS degradation in laundry wastewater at a pH close to neutral. The photo-Fenton process was carried out by reacting laundry wastewater with a Fenton reagent (Fe2+/H2O2), UV light, and ascorbic acid. The effect of ascorbic acid concentration, pH, and UV irradiation time was studied. In the photo-Fenton process, the concentration of anionic surfactant DBS was determined by UV/Visible spectrophotometer using a methylene blue reagent. The results showed that the tested laundry wastewater samples contained 154,98 mg L-1 of DBS anionic surfactant. The photo-Fenton process carried out at near neutral pH by reacting 20 mL of laundry wastewater with 5 mM Fe2+ reagent, 50 mM H2O2, 9 mM ascorbic acid, 60 min irradiation time, was able to reduce the concentration of DBS maximally up to 98.66%. The results of the kinetics study showed that the reaction of DBS degradation through the ascorbic acid-modified photo-Fenton process followed a second-order reaction with a reaction rate constant value of 0.0025 L mg-1 min-1. The photo-Fenton process at optimum conditions can reduce the concentration of DBS in laundry wastewater from 129,74 mg L-1 to 1,728 mg L-1 which has met the laundry wastewater quality standard of 5 mg L-1, so that laundry wastewater can be discharged into the environment.

Kata Kunci : photo-Fenton; ascorbic acid; neutral pH; DBS; laundry wastewater