Fenton试剂预处理综合印染废水的实验研究

采用Fenton试剂预处理综合印染废水,改善其可生化性.结果表明,各影响因素的显著性大小顺序是n(H2O2)/n(Fe2+)＞H2O2投加量＞反应时间＞起始pH值;当n(H2O2)/n(F2+)为5～10、H2O2投加量在1.3～2.5mmol/L、Fenton反应时间为20～30min、起始pH为3～5时,COD去除率能稳定在40%以下,而B/C能稳定在0.3以上.     

Fenton 絮凝工艺去除废水中的有机物试验

为了研究废水中有机物的去除问题,针对某企业含有机物废水进行了对比试验,采用了Fenton 絮凝联合工艺去除废水中的COD（化学需氧量）和浊度,考察了初始pH值、H2O2投加量、H2O2与Fe2+投加物质的量比、反应时间、絮凝剂投加量以及絮凝剂投加时的pH值对COD以及浊度去除效果的影响。结果表明,采用最佳工艺参数组合后,浊度去除率和COD的去除率分别为99.32%和97.27%。     

金属催化剂对Fenton试剂活性的影响因素分析

在分析Fenton氧化法作用机理的基础上,研究了金属催化剂Fe~(2+)/Fe~(3+)对Fenton试剂活性的影响。结果表明:Fe~(2+)和Fe~(3+)对Fenton试剂活性均具有催化作用,Fe~(2+)催化作用远大于Fe~(3+)催化作用;在H_2O_2投加量为12 mmol/L,反应温度为25℃,反应时间为25 min条件下,[Fe~(2+)]/[H_2O_2]的物质的量比为1∶10时,焦化含酚废水COD去除率最高达到90.2%(质量分数);在光照特别是紫外线协同作用下,Fe~(2+)和Fe~(3+)活性增大,且Fe~(3+)的活性增强趋势明显高于Fe~(2+)。     

Fenton氧化-混凝工艺处理焦化废水的研究

采用Fenton试剂氧化-混凝沉淀法深度处理焦化生化处理二沉池出水,考察了H2O2投加量、Fe2+/H2O2(物质的量比)、PFS(聚合硫酸铁)投加量、pH值、反应时间对TOC和COD去除效果的影响,确定了适宜的反应条件。试验结果表明,TOC和COD去除率最高分别达到90.7%和72.7%,出水COD浓度达到GB 8978—1996《国家污水综合排放标准》一级。     

铜电解液中聚丙烯酰胺的检测

本文采用梯度透析法除去铜电解液样品中的高酸、高铜背景,处理后的样品可直接使用凝胶色谱法检测聚丙烯酰胺浓度,并对方法的线性、回收率、精密度进行验证。结果表明：PAM浓度和峰面积有良好的线性关系,相关系数均为0.999 2,样品的加标回收率为89.5%～91.3%,相对标准偏差为4.8%～6.5%,该方法重复性良好,操作简便快速,适用于铜电解液中聚丙烯酰胺的检测。     

非均相Fenton法降解水中橙黄G的研究

采用针铁矿为催化剂,与H2O2可形成非均相芬顿(非均相Fenton)试剂对橙黄G(OG)进行降解试验,研究了pH值、催化剂用量、H2O2浓度、反应温度等对橙黄G(OG)降解过程的影响.结果表明,在反应温度为25℃,pH值为3.0,H2O2浓度为30.0mmol/L,针铁矿用量为1.0 g/L时,降解OG效果最好,180 min后质量浓度为50 mg/L的OG降解率为99.6%.OG的降解随着温度的升高而升高,但随着NaCl浓度的升高而降低.不同条件下进行的动力学研究表明,反应接近于表观一级反应,所得表观活化能E=42.18 KJ/mol.     

异相类Fenton催化剂降解废水中抗生素研究进展及发展趋势

水中抗生素具有成分复杂、毒性高和难于生物降解等特点,成为近些年水处理领域的研究热点。均相Fenton氧化技术（Fe2+/H₂O₂体系）因其反应快速、简单高效而备受青睐。而异相类Fenton氧化技术采用铁基固体催化剂代替液相Fe2+,能够有效减少含铁污泥的生成,同时拓宽反应的pH值范围,且催化剂可以回收利用,在近些年得到了快速发展,将其应用于抗生素的降解也取得了理想的效果。从异相类Fenton催化原理出发,综述了异相类Fenton催化剂降解抗生素的研究进展。基于异相类Fenton催化剂的核心问题,重点阐述了改善催化性能的方法、措施以及新的观点。针对异相类Fenton技术降解抗生素存在的问题提出了今后的发展方向。      

Cu2+作用下Fenton氧化处理苯酚废水研究

[目的]寻找Cu<'2+>存在条件下 Fenton 氧化处理苯酚模拟废水的最佳条件.[方法]研究不同浓度 H<,2>O<,2>、Fe<'2+>及 pH 下 Cu<'2+>的存在对 Fenton 氧化处理苯酚模拟废水的苯酚去除率的影响和对 COD 降解效果的影响.[结果]在苯酚浓度为 250 mg/L,最佳 pH 为 3.0,H<,2>O<,2>浓度为 297.5 mg/L,Fe<'2+>浓度为 140 mg/L 时,苯酚的最高去除率为 94.5%;在此条件下,Cu<'2+>浓度为 40 mg/L 时,苯酚最高去除率为 97.7%,提高了 3.2%.在 pH3.0、Cu<'2+>浓度 40mg/L 条件下,分别求得不同 Fe<'2+>/H<,2>O<,2>下的模型备件参数,结果表明 Fenton 氧化降解苯酚废水符合二级降解动力学反应模型.[结论]适当浓度的Cu<'2+>可提高 Fenton 氧化降解苯酚废水的效率.Fenton 氧化降解苯酚废水符合二级降解动力学反应模型.     

腐殖酸去除试剂对拜耳法生产氢铝白度的影响

针对某氧化铝厂拜耳法生产的氢氧化铝产品白度周期性波动的现象,分析认为,主要原因是拜耳法流程中腐殖酸含量的不断积累造成的.通过在稀释料浆中加入一定量的腐殖酸去除试剂,腐殖酸去除试剂会与铝酸钠溶液中的腐殖酸相互结合形成固体沉淀,随着赤泥排出流程,达到铝酸钠溶液的净化效果.结果表明,通过添加腐殖酸去除试剂可有效提高氢氧化铝产...     

Fenton法预处理合成制药废水研究

采用Fenton试剂法对合成制药废水进行预处理,研究了各因素对其处理效果的影响以及经Fenton试剂处理后废水可生化性的变化。通过正交试验、单因子分析、生化对比分析,确定最佳处理条件。为Fenton试剂法在处理合成制药废水的实际应用中奠定理论基础和提供试验依据。     

Degradation of MTBE Intermediates using Fenton’s Reagent

In a previous study, the chemical oxidation of methyl tert-butyl ether (MTBE) at low concentrations in water using Fenton’s reagent (FR) was investigated. At certain reaction conditions the process achieved 99.99% degradation of MTBE but it did not result in complete MTBE mineralization. In the present study, the major intermediate by-products generated during the reaction, such as tert-butyl formate (TBF), tert-butyl alcohol (TBA), methyl acetate, and acetone were separately used as parent contaminants and treated under the same reaction conditions initially used for MTBE (i.e., pH of the water, molar ratio of pollutant to FR) in order to compare their degradability by hydroxyl radicals generated from Fenton’s reaction. The results were compatible with the second order reaction rate constants for the reaction of hydroxyl radicals with each contaminant commonly available in the literature. The comparison of the degradation kinetics for each intermediate by-product provided information that aims at unveiling the limiting step(s) of the entire MTBE degradation pathway. In this context, it was found that (1) TBA was generated by reactions subsequent to those that produced TBF, (2) acetone was originated by at least three independent pathways involving direct hydroxyl radical attack on MTBE, TBF, and TBA, and (3) methyl acetate was formed exclusively from MTBE.     

金精矿的含硫试剂浸出工艺研究

用硫脲、硫代硫酸盐、硫氰酸盐、石硫合剂及改性石硫合剂等含硫试剂对某金精矿进行浸出试验,结果表明,石硫合剂和改性石硫合剂适于该金精矿的浸出,且在较优条件下浸出率可达85%以上。     

Cadmium Release from Four Sorbents during Treatment of Contaminated Soils by Catalyzed H2O2 Propagations (Modified Fenton’s Reagent)

The release of heavy metals from soils and subsurface solids is a significant concern during in situ chemical oxidation treatment. The release of cadmium sorbed on four solids of varied properties was investigated in slurries treated by catalyzed H2O2 propagations (CHP—modified Fenton’s reagent). Cadmium was released in all four solids in CHP reactions conducted at pH 3; however, aqueous cadmium concentrations decreased in CHP reactions conducted at pH 7. Cadmium release at pH 3 was directly proportional to the soil organic carbon (SOC) content of the four solids (R2 = 0.99), and may have been due to destruction of the SOC by hydroxyl radical in the reactions at pH 3. Scavenging of hydroxyl radical minimized the release of cadmium in CHP systems at pH 3, which is consistent with cadmium release resulting from destruction of SOC by hydroxyl radical. Scavenging of hydroxyl radical in CHP systems at pH 7 resulted in increased cadmium release, compared to pH 7 reactions without the hydroxyl radical scavenger isopropanol. Superoxide, the conjugate base of perhydroxyl radical (pKa = 4.8), was proposed as the desorbing species in the scavenged CHP reactions at pH 7. The results of this research demonstrate that cadmium release will likely be minimal in CHP reactions conducted at pH 7 if compounds that increase the activity of superoxide are not present at significant concentrations.     

Destruction of a Carbon Tetrachloride Dense Nonaqueous Phase Liquid by Modified Fenton’s Reagent

Destruction of a dense nonaqueous phase liquid (DNAPL) by soluble iron (III)-catalyzed and pyrolusite (β-MnO2)-catalyzed Fenton’s reactions (hydrogen peroxide and transition metal catalysts) was investigated using carbon tetrachloride (CT) as a model contaminant. In the system amended with 5 mM soluble iron (III), 24% of the CT DNAPL was destroyed after 3 h while CT dissolution in parallel fill-and-draw systems was minimal, indicating that CT was degraded more rapidly than it dissolved into the aqueous phase. Fenton’s reactions catalyzed by the naturally occurring manganese oxide pyrolusite were even more effective in destroying CT DNAPLs, with 53% degradation after 3 h. Although Fenton’s reactions are characterized by hydroxyl radical generation, carbon tetrachloride is unreactive with hydroxyl radicals; therefore, a transient oxygen species other than hydroxyl radicals formed through Fenton’s propagation reactions was likely responsible for CT destruction. These results demonstrate that Fenton-like reactions in which nonhydroxyl radical species are generated may provide an effective method for the in situ treatment of DNAPLs.     

Chemistry of Modified Fenton’s Reagent (Catalyzed H2O2 Propagations–CHP) for In Situ Soil and Groundwater Remediation

The use of modified Fenton’s reagent, or catalyzed H2O2 propagations (CHP), has become increasingly popular for the in situ and ex situ treatment of surface soils and the in situ remediation of the subsurface. The process is based on the catalyzed decomposition of hydrogen peroxide by soluble iron, iron chelates, or iron minerals to generate the strong oxidant hydroxyl radical as well as other reactive oxygen species. Some of these species function as reductants and nucleophiles and may be responsible for the enhanced treatment of sorbed and nonaqueous phase liquid (NAPL) contaminants that is sometimes observed in the field. This paper serves as a review of the process chemistry of CHP; the goal is to provide researchers and practitioners with fundamental concepts that will aid in applying the CHP process to soil and groundwater contamination. Although the importance of well placement and the method of reagent injection must be considered in CHP remediation, understanding and promoting the most effective process chemistry is essential to successful soil and groundwater remediation.     

N,N''''-二(十二烷基)乙二胺二乙酸萃取钕的研究

研究了以N,N’-二(十二烷基)乙二胺二乙酸(简写为H2R2Y)为络合剂、氯仿作为稀释剂萃取稀土钕的行为。考察了水相酸度、萃取剂浓度、温度、相比等对萃取率的影响。用摩尔比法和电导法确定了R2H2Y与N d3+的络合比为2∶1。实验表明,钕的萃取率随络合剂浓度增大而增大,分配比在22℃~35℃范围内随温度的升高而降低,在pH=6~7范围内,H2R2Y对N d3+的萃取率接近100%。     

工业硅除钛的研究

为了去除工业硅中的杂质制备太阳能级硅,利用工业硅凝固过程中钛在固体和液体中溶解度的差异,采用定向凝固法去除工业硅中的杂质钛。实验结果表明,钛的去除效率可达96.7%,工业硅中钛的含量可以降到4×10-6,说明利用定向凝固法去除工业硅中的钛是可行的。