在氧化材料領(lǐng)域，目前常用的材料有Fenton試劑、過碳酸鈉、高錳酸鉀、臭氧、活化過硫酸鈉等。其中，過硫酸鈉憑借氧化還原電位（E0=2.01V）高、性質(zhì)比過氧化氫穩(wěn)定、可以在土壤中傳輸更長(zhǎng)距離、便宜等優(yōu)勢(shì)，近年來穩(wěn)坐有機(jī)污染土壤修復(fù)應(yīng)用的“頭把交椅”。
In the field of oxidizing materials, the commonly used materials include Fenton reagent, sodium percarbonate, potassium permanganate, ozone, activated sodium persulfate, etc. Among them, sodium persulfate, with its high redox potential (E0 = 2.01v), more stable properties than hydrogen peroxide, longer transmission distance in soil and low price, has been firmly in the "top position" in the remediation and application of organic polluted soil in recent years.
過硫酸鈉在常溫條件下反應(yīng)速率低，對(duì)有機(jī)污染物的降解效果不顯著。然而，在熱、過渡金屬離子（Fe2+、Fe3+等）、OH-等條件的激發(fā)下，會(huì)活化分解為·SO4-（E0=2.6V），反應(yīng)速率大幅度提升。
The reaction rate of sodium persulfate is low at room temperature, and the degradation effect of organic pollutants is not significant. However, under the excitation of heat, transition metal ions (Fe2 +, Fe3 +, etc.) and oh -, it will be activated and decomposed into · SO4 - (E0 = 2.6V), and the reaction rate will be greatly improved.
既然過硫酸鈉在多種條件下均可被，那么，過硫酸鈉在不同條件下被的機(jī)理特征及作用效果又如何呢？帶著以上疑問，高能環(huán)境修復(fù)技術(shù)研發(fā)團(tuán)隊(duì)針對(duì)不同方式過硫酸鈉進(jìn)行了實(shí)驗(yàn)研究。
Since sodium persulfate can be activated under various conditions, what are the mechanism characteristics and effect of sodium persulfate activated under different conditions? With the above questions, the R & D team of high-energy environmental remediation technology conducted experimental research on different ways to activate sodium persulfate.
▲紅外測(cè)油儀-有機(jī)污染物檢測(cè)
▲ infrared oil detector - organic pollutant detection
▲GCMS-有機(jī)污染物檢測(cè)
▲ GCMS organic pollutant detection
▲項(xiàng)目現(xiàn)場(chǎng)小試
▲ project site pilot test
▲項(xiàng)目現(xiàn)場(chǎng)中試
▲ project site pilot test
通過實(shí)驗(yàn)室檢測(cè)及在多個(gè)項(xiàng)目現(xiàn)場(chǎng)試驗(yàn)，結(jié)合文獻(xiàn)調(diào)研資料，對(duì)不同方式過硫酸鈉的機(jī)理及特征總結(jié)如下：
The mechanism and characteristics of different ways to activate sodium persulfate are summarized as follows through laboratory testing and field tests in multiple projects, combined with literature research data:
（1）熱
(1) Thermal activation
升溫30°以上，過硫酸鈉被產(chǎn)生硫酸根自由基：
When the temperature rises above 30 °, sodium persulfate is activated to produce sulfate radical:
體系溫度大于50℃，反應(yīng)1周左右，過硫酸鈉對(duì)TPH的降解效率大于90%。
The degradation efficiency of TPH by sodium persulfate was more than 90% when the system temperature was more than 50 ℃ for about 1 week.
（2）金屬離子
(2) Metal ion activation
過硫酸鈉被Fe（II）或Fe（III）發(fā)生系列反應(yīng)：
Sodium persulfate is activated by Fe (II) or Fe (III) to produce a series of activation reactions:
Fe（II）過硫酸鈉效率高、反應(yīng)劇烈、現(xiàn)象明顯，體系升溫明顯，反應(yīng)1周左右，過硫酸鈉對(duì)TPH降解率大于90%，對(duì)PAHs也有良好的降解效果。
Fe (II) activated sodium persulfate has high efficiency, violent reaction and obvious phenomenon. The temperature rise of the system is obvious. The degradation rate of TPH is more than 90% and PAHs is also good.
（3）過氧化氫
(3) Hydrogen peroxide activation
過硫酸鈉被過氧化氫或過碳酸鈉產(chǎn)生硫酸根自由基：
Sodium persulfate is activated by hydrogen peroxide or sodium percarbonate to produce sulfate radical:
該反應(yīng)體系為雙氧化系統(tǒng)（由一種氧化劑另一種氧化劑），反應(yīng)劇烈，升溫明顯，反應(yīng)1周左右，過硫酸鈉對(duì)TPH降解效率大于90%，對(duì)PAHs也有良好的降解效果，對(duì)有機(jī)氯農(nóng)藥類污染物也有一定的降解能力。
The reaction system is a double oxidation system (one oxidant activates another oxidant). The reaction is intense and the temperature rises obviously. After reaction for about 1 week, sodium persulfate has a degradation efficiency of more than 90% for TPH, a good degradation effect for PAHs, and a certain degradation capacity for organochlorine pesticide pollutants.
（4）堿
(4) Alkali activation
控制體系pH＞11時(shí)，過硫酸鈉被堿產(chǎn)生羥基自由基：
When the pH of the control system is > 11, sodium persulfate is activated by alkali to produce hydroxyl radical:
堿反應(yīng)體系對(duì)pH要求較高，隨pH升高反應(yīng)速率有升高趨勢(shì)，pH升13~14時(shí)，反應(yīng)速率升高幅度漸緩。但采用這種方式后期需要投加酸性物質(zhì)中和強(qiáng)堿性，對(duì)土壤體系理化性質(zhì)影響較大。
The alkali activated reaction system has high requirements for pH, and the reaction rate tends to increase with the increase of pH. when the pH rises to 13 ~ 14, the increase of reaction rate slows down. However, this activation method needs to add acidic substances to neutralize strong alkalinity in the later stage, which has a great impact on the physical and chemical properties of the soil system.
相對(duì)了解機(jī)理來說，大家更關(guān)注不同方式過硫酸鈉的性能以及對(duì)有機(jī)污染物的降解能力。
Compared with understanding the mechanism, people pay more attention to the performance of sodium persulfate activated by different activation modes and the degradation ability of organic pollutants.
分別將熱、Fe（II）、過氧化氫、堿4種方式的過硫酸鈉作用于總石油烴（TPH）、多環(huán)芳烴（PAHs）、有機(jī)氯農(nóng)藥3種典型有機(jī)污染土壤中進(jìn)行實(shí)驗(yàn)，得出以下結(jié)論：
Sodium persulfate activated by heat, Fe (II), hydrogen peroxide and alkali was applied to three typical organic contaminated soils: total petroleum hydrocarbons (TPH), polycyclic aromatic hydrocarbons (PAHs) and organochlorine pesticides. The following conclusions were obtained:
熱、Fe（II）、過氧化氫、堿4種方式對(duì)土壤中TPH的降解效果良好，降解效率均可達(dá)90%以上。
Heat, Fe (II), hydrogen peroxide and alkali have good degradation effects on TPH in soil, and the degradation efficiency can reach more than 90%.
熱、堿2種方式對(duì)土壤中多環(huán)芳烴、有機(jī)氯農(nóng)藥的降解能力相對(duì)Fe（II）、過氧化氫2種方式較弱。
The degradation ability of heat and alkali activation methods to polycyclic aromatic hydrocarbons and organochlorine pesticides in soil is weaker than that of Fe (II) and hydrogen peroxide.
4種方式對(duì)土壤中有機(jī)氯農(nóng)藥的降解效果均不理想。
The degradation effects of four activation methods on organochlorine pesticides in soil were not ideal.
過氧化氫過硫酸鹽雖然效率高、污染物降解效果好，但對(duì)過氧化氫的消耗量較大，過氧化氫的少量多次添加有利于維持氧化能力的同時(shí)節(jié)約氧化劑。
Although hydrogen peroxide activated persulfate has high efficiency and good pollutant degradation effect, it consumes a large amount of hydrogen peroxide. A small amount of hydrogen peroxide added for many times is conducive to maintaining oxidation capacity and saving oxidant.
