Kinetics of zero-valent iron reductive transformation of the anthraquinone dye Reactive Blue 4
Kinetics of zero-valent iron reductive transformation of the anthraquinone dye Reactive Blue 4
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DOI：
10.1016/j.jhazmat.2008.03.033
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发表时间：
2008-12-30
影响因子：
13.6
通讯作者：
Pavlostathis, Spyros G.
中科院分区：
文献类型：
--
作者：
Epolito, William J.;Yang, Hanbae;Pavlostathis, Spyros G.
在批量试验中评价了操作条件和初始染料浓度对使用零价铁（ZVI）屑的纺织染料活性蓝4（RB 4）的还原转化（脱色）的影响。脱色率随着pH值的降低和温度的增加，混合强度，并添加盐（100克L-1 NaCl）和碱（3克L-1碳酸钠和1克L-1 NaOH），典型的纺织品活性染料浴的条件下，ZVI RB 4脱色动力学在一个单一的初始染料浓度进行了评估，使用伪一阶模型。在染浴条件下，RB 4初始浓度为1000 mg L-1时，假一级速率常数（k（obs））为0.029 +/- 0.006 h（-1），对应的半衰期为24.2 h，ZVI表面积归一化速率常数（k（SA））为2.9 x 10（-4）L m（-2）h（-1）。然而，随着初始染料浓度的增加，k（obs）降低，表明ZVI表面反应位点饱和。基于活性位点饱和模型，初始脱色速率值作为初始染料浓度的函数的非线性回归得到最大脱色速率（V-m）为720 +/- 88 mg L-1 h（-1），半饱和常数（K）为1299 +/- 273 mg L-1。RB 4通过还原转化脱色，这基本上是不可逆的（2-5%再氧化），被认为是主要的脱色机制。然而，某种程度的RB 4不可逆吸附不能完全忽略。本研究的结果表明，ZVI处理是一种很有前途的商业，蒽醌轴承，废活性染料浴脱色技术。(C)2008 Elsevier B. V.保留所有权利。
The effect of operational conditions and initial dye concentration on the reductive transformation (decolorization) of the textile dye Reactive Blue 4 (RB4) using zero-valent iron (ZVI) filings was evaluated in batch assays. The decolorization rate increased with decreasing pH and increasing temperature, mixing intensity, and addition of salt (100 g L-1 NaCl) and base (3 g L-1 Na2CO3 and 1 g L-1 NaOH), conditions typical of textile reactive dyebaths, ZVI RB4 decolorization kinetics at a single initial dye concentration were evaluated using a pseudo first-order model. Under dyebath conditions and at an initial RB4 concentration of 1000 mg L-1, the pseudo first-order rate constant (k(obs)) was 0.029 +/- 0.006 h(-1), corresponding to a half-life of 24.2 h and a ZVI surface area-normalized rate constant (k(SA)) of 2.9 x 10(-4) L m(-2) h(-1). However, as the initial dye concentration increased, the k(obs) decreased, suggesting saturation of ZVI surface reactive sites. Non-linear regression of initial decolorization rate values as a function of initial dye concentration, based on a reactive sites saturation model, resulted in a maximum decolorization rate (V-m) of 720 +/- 88 mg L-1 h(-1) and a half-saturation constant (K) of 1299 +/- 273 mg L-1. Decolorization of RB4 via a reductive transformation, which was essentially irreversible (2-5% re-oxidation), is believed to be the dominant decolorization mechanism. However, some degree of RB4 irreversible sorption cannot be completely discounted. The results of this study show that ZVI treatment is a promising technology for the decolorization of commercial, anthraquinone-bearing, spent reactive dyebaths. (C) 2008 Elsevier B.V. All rights reserved.