Developing and application of an effective approach for enhancing water purity of highway tunnel drainage system
The abundance of organic matter in the highway tunnel drainage systems may lead to siltation and pose a significant risk to ecological environment.This study introduces a peroxodisulfate-based Fenton-like system(E/Fe(Ⅲ)/PMS)under an electric current to efficiently remove chemical oxygen demand(COD)from highway tunnel drainage system.An experiment of single factor was conducted to explore the impact of current density,Fe(Ⅲ),PMS dosages,and the initial solution PH on COD removal.The results revealed a remarkable 95.3%reduction in COD within 30 min at a low power consumption of 0.43 kWh/m3.A continuous Fe(Ⅲ)/Fe(Ⅱ)redox reaction cycle was achieved through the continuous reduction of Fe(Ⅲ)to Fe(Ⅱ)facilitated by electron supply at the cathode,leading to sustained PMS activation.Electron paramagnetic resonance(EPR)experiments illustrated the catalytic production of sulfate radicals(SO-4),hydroxyl radicals(HO),and singlet oxygen(1 O2)by Fe(Ⅱ).Based on probe experiments result,steady-state concentrations of SO-4,HO,and 1 O2 were calculated to be 1.42×10-12 M,4.15×10-12 M,and 4.68×10-12 M,respectively.Additionally,Fe(Ⅲ)exhibited stable catalytic activity under acidic conditions,with rapid activation achieved by increasing solution pH.The recovery of Fe(Ⅲ)was expedited by elevating the solution pH and adding heavy metal trapping agent.This study presents a novel approach for silation treatment and water purification in highway tunnel drainage systems.
water purification in highway tunnelpersulphateiron ionadvanced oxidation processestunnel drainage systems siltation
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