Abstract

The paper reports the oxidative decolorization of the direct blue 14 (DB-14) dye in an aqueous phase via an ecologically friendly electrochemical advanced oxidation process. The investigation of several experimental conditions such as the solution pH, initial concentrations of the oxidant, the dye, and current density was carried out in a single-compartment electrolytic cell with the use of an iron sheet as anodic material, the graphite plate being the cathodic material. The optimal operating conditions were found to be as follows: (DB-14)₀—500 mg/L; (H₂O₂)₀—35 mM concentration; pH 3 using 0.1 M Na₂SO₄ salt as supportive electrolyte at room temperature. It has been observed that the dissolved iron (Fe²⁺) content from the anode was continuously increasing in aqueous media on passing a constant current to it. Initially, it was 1.58 mM, then 4.46 mM (after 30 min of reaction time), and 5.35 mM of dissolved Fe²⁺ for 60 min of the reaction time. The study of kinetics for the decolorization of DB-14 shows that the degradation kinetics follows the second order, with the reaction rate being constant: k₂—0.5 × 10^–4 mgL^–1 min^–1. Electrochemical oxidation of DB-14 reduces the chemical oxygen demand of the colored solution. The unit energy demand, expressed in kWh/kg of the chemical oxygen demand reduced, for optimum experimental parameters have also been determined.

中文翻译：

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直接蓝14在水相中的电化学氧化：实验和动力学研究。

摘要

该论文报道了通过生态友好的电化学高级氧化工艺在水相中直接蓝14（DB-14）染料的氧化脱色。使用铁片作为阳极材料，在单室电解槽中研究了几种实验条件，例如溶液的pH值，氧化剂的初始浓度，染料和电流密度。阴极材料。发现最佳操作条件如下：（DB-14）₀ —500 mg / L；（H ₂ O ₂）₀ —35 mM浓度；使用0.1 M Na ₂ SO _4的pH 3在室温下，盐作为支持电解质。已经观察到，在通过恒定电流的情况下，来自阳极的溶解铁（Fe ²⁺）含量在水性介质中持续增加。最初，反应时间为60分钟，反应温度为1.58 mM，然后为4.46 mM（在反应时间30分钟后），而溶解的Fe ²⁺为5.35 mM 。DB-14脱色动力学研究表明，降解动力学遵循第二级，反应速率恒定：k ₂ -0.5×10 ^–4 mgL ^–1 min ^–1。DB-14的电化学氧化减少了有色溶液的化学需氧量。还确定了用于最佳实验参数的单位能量需求（以kWh / kg化学需氧量表示）。