Photo Fenton oxidation of metal plating wastewater: Optimization of peroxide/iron ratio and UV radiation

Öz

The current study evaluates the ability of a real industrial (metal plating) wastewater with a relatively low organic load (682 mg/L Chemical oxygen demand (COD) and 203 mg/L Total organic carbon (TOC)) to be treated by photo-Fenton oxidation in a UV-assisted chamber using the conventional Fenton process. Iron (Fe2+) dosage, hydrogen peroxide (H2O2) concentration, H2O2/Fe2+ ratio and pH were evaluated as treatment factors due to their direct effects on COD and TOC oxidation. In the classical Fenton set, the optimum values of pH 3.0, Fe+2 concentration 250 mg/L and H2O2 content 450 mg/L resulted in optimum removal efficiencies of up to 83,3% and 81,4% in COD and TOC removal after 60 min, respectively; for the photo-Fenton process, the optimum conditions were 175 mg/L Fe2+, 350 mg/L H2O2. According to H2O2/Fe2+ ratios, the maximum COD and TOC removal efficiencies in 682 mg/L of industrial wastewater were achieved as 89,2% and 84,5% after 45 min, respectively. The oxidation efficiency expressed as COD reduction was clearly characterized by first-order reaction kinetics in the classical Fenton (r2=0.992), while the BMG model described high agreement for both processes (r2=0.991 and 0.996).

Anahtar Kelimeler

• Industrial wastewater
• metal plating
• advanced oxidation
• UV
• photo-Fenton

Metal kaplama atıksularının Fenton oksidasyonu: Peroksit/demir oranı ve UV radyasyonunun optimizasyonu

Öz

Mevcut çalışma, nispeten düşük organik yüke sahip (Kimyasal oksijen ihtiyacı, KOI 682 mg/L ve Toplam organik karbon (TOC) 203 mg/L) gerçek bir endüstriyel (metal kaplama) atık suyunun, geleneksel Fenton işlemi kullanılarak UV destekli bir kabinde foto-Fenton oksidasyonu ile arıtılma kabiliyetini değerlendirmektedir. Demir (Fe2+) dozajı, hidrojen peroksit (H2O2) konsantrasyonu, H2O2/Fe2+ oranı ve pH, COD ve TOC oksidasyonu üzerindeki doğrudan etkileri nedeniyle arıtma faktörleri olarak değerlendirilmiştir. Klasik Fenton setinde, pH 3,0, Fe+2 konsantrasyonu 250 mg/L ve H2O2 içeriği 450 mg/L optimum değerleri, sırasıyla 60 dakika sonra COD ve TOC gideriminde %83,3'e ve %81,4'e varan optimum giderim verimlilikleriyle sonuçlanmıştır; foto-Fenton işlemi için optimum koşullar 175 mg/L Fe2+, 350 mg/L H2O2'dir. H2O2/Fe2+ oranlarına göre, 682 mg/L endüstriyel atıksuda 45 dakika sonunda maksimum KOİ ve TOK giderim verimleri sırasıyla %89,2 ve %84,5 olarak elde edildi. KOİ indirgemesi olarak ifade edilen oksidasyon verimi, klasik Fenton modelinde birinci dereceden reaksiyon kinetiği ile açıkça karakterize edilirken (r2=0,992), BMG modeli her iki proses için de yüksek uyum gösterdi (r2=0,991 ve 0,996).

Anahtar Kelimeler

• Endüstriyel atıksu
• metal kaplama
• ileri oksidasyon
• UV
• photo Fenton

Kaynakça

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