Efficiency of activated carbon to transform ozone into *OH radicals: influence of operational parameters.
Efficiency of activated carbon to transform ozone into *OH radicals: influence of operational parameters.
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DOI：
10.1016/j.watres.2005.05.026
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发表时间：
2005-09
期刊：
影响因子：
12.8
通讯作者：
M. Sánchez-Polo;U. Gunten;J. Rivera-Utrilla
中科院分区：
文献类型：
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作者：
M. Sánchez-Polo;U. Gunten;J. Rivera-Utrilla
基于先前的研究结果（Jans， U, hoign<e:1>， J., 1998）。臭氧科学。（Eng. 20, 67-87），量化了操作参数（碳剂量、臭氧剂量、碳类型和碳处理时间）对臭氧转化为OH自由基的活性的影响。系统中活性炭的存在增加了臭氧分解常数（kD），并且根据添加的活性炭类型，OH自由基浓度与臭氧浓度的比值Rctvalue （[OH]/[O3]）增加了3-5倍。结果表明，活性炭的表面化学性质和结构特性决定了其将臭氧转化为OH自由基的活性。在这个过程中，最有效的碳是那些碱度高、表面积大的碳。所得结果表明，臭氧与活性炭表面存在的吡啶基团之间的相互作用增加了体系中[公式：见文]自由基的浓度，促进了臭氧向OH自由基的转化。活性炭的活性随着臭氧暴露时间的延长而降低。这可能表明活性炭并不是真正起到催化剂的作用，而是作为臭氧转化为OH自由基的常规引发剂或促进剂。在活性炭（0.5g/L）的存在下，对苏黎世湖的水（[O3]=1mg/L）进行臭氧化处理，导致kd和rct值分别增加10倍和39倍，从而有利于去除臭氧抗性污染物。此外，在苏黎世湖水体臭氧化过程中，活性炭的存在导致在处理的前60分钟内溶解有机碳的含量减少了40%。低浓度溶解性有机物（DOM）在活性炭表面的吸附并没有改变其引发/促进臭氧转化为OH自由基的能力。
Based on previous findings (Jans, U., Hoigné, J., 1998. Ozone Sci. Eng. 20, 67–87), the activity of activated carbon for the transformation of ozone into OH radicals including the influence of operational parameters (carbon dose, ozone dose, carbon-type and carbon treatment time) was quantified. The ozone decomposition constant (kD) was increased by the presence of activated carbon in the system and depending on the type of activated carbon added, the ratio of the concentrations of OH radicals and ozone, the Rctvalue ([OH]/[O3]), was increased by a factor 3–5. The results obtained show that the surface chemical and textural characteristics of the activated carbon determines its activity for the transformation of ozone into OH radicals. The most efficient carbons in this process are those with high basicity and large surface area. The obtained results show that the interaction between ozone and pyrrol groups present on the surface of activated carbon increase the concentration of [Formula: see text] radicals in the system, enhancing ozone transformation into OH radicals. The activity of activated carbon decreases for extended ozone exposures. This may indicate that activated carbon does not really act as a catalyst but rather as a conventional initiator or promoter for the ozone transformation into OH radicals. Ozonation of Lake Zurich water ([O3]=1mg/L) in presence of activated carbon (0.5g/L) lead to an increase in the kDand Rctvalue by a factor of 10 and 39, respectively, thereby favouring the removal of ozone-resistant contaminants. Moreover, the presence of activated carbon during ozonation of Lake Zurich water led to a 40% reduction in the content of dissolved organic carbon during the first 60min of treatment. The adsorption of low concentrations of dissolved organic matter (DOM) on activated carbon surfaces did not modify its capacity to initiate/promote ozone transformation into OH radicals.