CoFe2O4的制备及其活化过硫酸盐降解磺胺甲恶唑

采用简单的共沉淀法在不同煅烧温度下成功合成了一系列铁酸钴材料（CoFe2O4-X），通过SEM，XRD，BET，XPS等表征手段对其结构组成进行了分析，并将其用于活化过一硫酸盐（PMS）以降解磺胺甲恶唑（SMX）。考察了催化剂投加量、PMS用量、pH值和无机离子对SMX降解的影响。结果表明，550℃煅烧温度下获得的CoFe2O4-550具有最佳的催化性能，在最佳反应条件下，20 min内，SMX的降解率可高达95%，且TOC去除率可达80%。同时，CoFe2O4-550/PMS反应体系具有较广的pH适用范围（pH=5.00-9.00）。CoFe2O4-550催化剂可磁性回收，具有较好的稳定性和重复使用性。自由基淬灭实验表明，在该降解反应过程中产生了大量的SO4-?和?OH自由基，并提出了相应的催化降解机理。这项工作将为有效处理含有SMX化合物的废水提供一种新思路。     

复方磺胺甲噁唑片降解杂质分析

通过考察复方磺胺甲噁唑片的降解途径以及降解产物,有效地进行药物杂质分析,提高药品质量控制水平。取复方磺胺甲噁唑片、空白辅料、空白辅料加甲氧苄啶和空白辅料加磺胺甲噁唑四种组分的样品分别进行破坏试验,考察各样品在光、热、酸、碱、氧化条件下的降解情况。主要降解杂质有在氧化破坏条件下产生磺胺甲噁唑氧化杂质1和2、甲氧苄啶杂质F,光照破坏条件下产生较大的磺胺甲噁唑杂质C、D。通过降解杂质的研究,可以有效规避制剂处方工艺和储存等环节产生降解杂质的风险,还可以采用实验中液相色谱条件同时监测复方磺胺甲噁唑片中各降解杂质,提升质量标准。     

铁激活过硫酸盐去除水中难降解污染物

本文对铁及其离子(Fe(0)、Fe(Ⅱ)及F(Ⅲ))激活过硫酸盐处理水中难降解污染物的机理、处理效果与影响进行了总结,并对铁激活过硫酸盐降解有机污染物的发展方向提供了建议.     

氮硫掺杂生物炭/过一硫酸盐体系降解水中磺胺异唑

利用高温热解的方式制备由氮、硫元素掺杂改性的生物碳质纤维材料,并借用扫描电镜（SEM）、X射线衍射（XRD）、X射线光电子能谱（XPS）等多种技术对材料性质进行分析。实验以制备材料为催化剂活化过一硫酸盐（PMS）降解水中的磺胺异唑（SSX）,研究其降解效果,探讨材料活化PMS的机理。结果表明：N、S的掺杂显著提升了材料活化PMS降解SSX的性能,其中NSC-5的催化性能最佳,当NSC-5投加量为0.4g/L、PMS浓度为0.25mmol/L、SSX浓度为10mg/L时,反应90min后可去除80%以上,反应速率是生物碳质材料（BC）参与进行反应的2.7倍,这与其表面增加的官能团相关。电子顺磁共振（EPR）结果表明,SSX降解过程中起主要作用的组分是单线态氧（¹O₂）、硫酸根自由基（·SO{}_{\mathrm{4}}^{-}）和羟基自由基（·OH）,氮硫的掺杂加快了电子转移速率,进而提高材料的催化活性。     

热活化过硫酸盐降解水中卡马西平

以典型抗癫痫药物卡马西平为目标污染物, 研究热活化过硫酸盐(thermally activated persulfate, TAP)技术对其的降解效果。此外, 还考察了过硫酸盐初始浓度、温度和零价铁投加量等对降解效果的影响。结果表明, 随着过硫酸盐初始浓度的增加, 降解速率常数提高, 不同温度下卡马西平降解速率常数与过硫酸盐初始浓度表现出良好的线性关系。提高系统温度能够提高卡马西平的降解速率。TAP氧化卡马西平符合拟一级动力学, 反应活化能E_a为(120.4±2.6)kJ·mol^-1。在TAP系统中加入少量零价铁能够显著地提高卡马西平的降解速率和矿化度。当温度为60℃时, 零价铁的最佳投加量为0.05 g·L^-1。硫酸自由基易于对卡马西平分子结构中氮杂卓环的烯烃双键进行攻击, 主要生成羟基化卡马西平、环氧卡马西平、吡啶类醛和酮等中间产物。     

臭氧化降解给水系统中磺胺甲噁唑的试验研究

研究了臭氧对难降解的磺胺甲口唑(SMZ)的氧化效果,考察了pH、臭氧投加量、SMZ含量、自由基清除剂的去除对反应的影响,并对反应机理进行了初探.结果表明,在强碱性溶液中,O_3分解产生·OH,通过·OH的强氧化作用,质量浓度为200μg·L~(-1)的SMZ废水在臭氧投加量为4mg·L~(-1)条件下,去除率可达56.83%.臭氧氧化对SMZ有一定的降解作用,尤其在高pH条件下,·OH可将SMZ氧化生成相对分子质量较小的物质,主要是对氨基苯磺酰胺、NO_3~-以及有机酸.     

纳米催化电解法处理磺胺甲噁唑废水

利用纳米催化电解法处理磺胺甲噁唑废水,研究pH、盐度、电解电压、电解时间等因素对处理磺胺甲噁唑的影响。结果表明,对于浓度为80 mg/L的磺胺甲噁唑废水,最佳的电解条件是pH=13,盐度为15‰,电解电压为6 V。在此条件下,COD_(Mn)的去除率达到76%,磺胺甲噁唑的去除率为83%,说明纳米催化处理对此类难以生物降解的抗生素具有很好的去除效果,为该类废水的处理提供了一种可行的方法。     

Fenton氧化降解水中磺胺甲恶唑的研究

以 COD 为评价指标,考察了 Fenton氧化法对水中磺胺甲噁唑（SMX）去除效果。通过探讨 H₂O₂投加量、Fe²⁺投加量以及溶液初始 pH 对 COD 去除的影响,确定了 Fenton 去除 SMX 的优化工艺条件为：pH=3,H₂O₂投加量为 10mmol/L,Fe²⁺投加量为 1.0 mmol/L,在该条件下,COD 去除率可达 71.8%。与经典动力学相比,伪动力学模型能很好拟合 SMX 的去除过程,其中伪二级动力学模型的相关系数为 0.999 9。此外,根据 GC/MS 分析结果,推测了 SMX 可能的降解途径。     

超声活化过硫酸盐降解废水中有机污染物的研究进展

综述了超声活化过硫酸盐处理技术简要的工作原理,对有机污染物的处理效果以及其在污水处理中的应用情况。随着社会经济的发展,水环境污染日益恶化,活化过硫酸盐在有机废水的处理中具有良好的效果,因此近年来引起了广泛的关注。在各种活化技术中,超声活化作为一种新兴的方法,近年来受到越来越多的关注。但其仍存在一定的不足之处,提出了未来应加强研究该工艺的作用机理,增加对反应中间产物生物有效性的分析以及加大其在实际中应用的建议。     

LaCoO3钙钛矿活化过一硫酸盐降解萘普生

在催化活化过一硫酸盐(PMS)降解水中污染物的反应中,通过添加钴基钙钛矿提高反应效率。利用溶胶凝胶法制备了LaCoO₃钙钛矿,通过实验评估LaCoO₃/PMS体系对非甾体抗炎药萘普生（NAP）的降解效果。分析了LaCoO₃投加量、PMS投加量、反应初始pH、Cl^-浓度和腐殖酸（HA）对NAP去除率的影响以及该体系的矿化能力。结果表明NAP降解的反应速率随LaCoO₃和PMS投加量增加而增大;反应初始pH在5.0时NAP降解效果最好;溶液中存在Cl^-对降解有促进效果,且Cl^-浓度越大促进效果越明显;腐殖酸（HA）对反应有一定程度的抑制效果;LaCoO₃在重复利用5次时仍有较好的稳定性。此外,自由基淬灭实验结果表明在LaCoO₃/PMS体系中SO₄^·-为主要活性物质。     

盐助溶液燃烧法制备MnFe2O4催化过一硫酸盐降解双酚A

采用盐助溶液燃烧法制备磁性铁酸锰（MnFe₂O₄）,催化过一硫酸氢盐（PMS）氧化降解水溶液中的双酚A。通过XRD、BET等手段对制备的铁酸锰催化剂进行了表征。探究了MnFe₂O₄投加量、PMS投加量、溶液初始pH、淬灭剂、共存离子等因素对双酚A降解效果的影响,评估了MnFe₂O₄催化剂的循环利用性能。结果表明,MnFe₂O₄和PMS的最合理投加量分别为 0.3 g/L、0.3 mmol/L,初始pH为11.0时双酚A降解效果最好,60 min内的降解率可达99.3%。淬灭实验表明,催化体系中同时存在多种活性物质,¹O₂是主要活性物种。溶液中Cl^-、HCO₃^-和HPO₄^2-等共存离子的存在影响双酚A的降解。双酚A在60 min内的TOC去除率为34.9%,苯环断裂和开环反应是其主要降解路径。MnFe₂O₄催化剂循环使用三次后,双酚A的降解率仍保持在90.0%左右。     

Degradation of bisphenol A by peroxymonosulfate activated by MnFe2O4 prepared by salt-assisted solution combustion synthesis

Magnetic manganese ferrite (MnFe₂O₄) prepared by the salt-assisted solution combustion synthesis was used to activate peroxymonosulfate(PMS) to oxidize bisphenol A in aqueous solution. The prepared MnFe₂O₄ catalyst was characterized by XRD and BET. The effects of MnFe₂O₄ dosage, PMS dosage, initial pH of the solution, quencher, and co-existing ions on the degradation of bisphenol A were investigated. The reusability of the MnFe₂O₄ catalyst was evaluated through cycling experiments. The results showed that the best dosages of MnFe₂O₄ and PMS were 0.3 g/L and 0.3 mmol/L, respectively. When the initial pH was 11.0, the degradation rate of bisphenol A was 99.3% in 60 min. When putting some quenchers into the MnFe₂O₄/PMS catalytic system, all of them showed depression effects on degradation of bisphenol A, and the ¹O₂ was the main active species. The co-existing ions such as Cl^-, HCO₃^-, and HPO₄^2- in solution affected the degradation of bisphenol A. The TOC removal rate of bisphenol A within 60 min was 34.9%, the rupture and opening of benzene ring are the main reaction pathways. After the MnFe₂O₄ catalyst was recycled three times, the degradation rate of bisphenol A remained at about 90.0%.     

Degradation of biorefractory furaltadone in aqueous solution by ozonation

BACKGROUND: Furaltadone (FD), a nitrofuran derivative, is a highly effective chemotherapeutic drug. In China the FD wastewater discharged by the pharmaceutical industry is high in organics and biorefractory compounds. The objective of this study was to investigate the degradation mechanism of FD in aqueous solution by ozone oxidation. Preliminary results on the reaction mechanism were obtained using three different spectral analysis techniques. RESULTS: The ozonation mechanism was significantly affected by the pH value. At low pH values the primary reaction is direct oxidation of ozone, an incomplete oxidisation, which can only destroy the FD molecule's conjugated structure. At high pH values the major reaction changes to hydroxyl radical oxidation. FD can be rapidly oxidised into CO₂, H₂O, NH₃, NO , HCHO, oxalic acid and other aliphatic acids of low molecular weight, which can be entirely mineralised by continued ozonation. CONCLUSION: The pH value significantly influences the mode of FD ozonation. The present experiment suggests a potentially useful pretreatment method for conventional biological treatment of wastewater containing FD. Copyright © 2008 Society of Chemical Industry     

超声辅助MnO_2活化过一硫酸盐降解罗丹明B

选取罗丹明B(Rh B)为降解底物,采用超声辅助MnO_2活化过一硫酸盐(PMS)的方法降解水中的Rh B。以Rh B染料废水的色度去除率为指标,探究PMS投加量、MnO_2投加量、超声功率、Rh B初始pH和浓度,温度对Rh B降解效果的影响及其该法的使用范围。结果表明,最优的Rh B降解条件为PMS 0.5 g/L,MnO_20.8 g/L,超声功率80 W。此外,该方法可在温度为45⁶0℃和pH为中性范围内使用。催化剂重复3次,Rh B的色度去除率基本不变。该研究结果可为杂环碱性染料工业废水的处理提供技术指导。     

Degradation of 2,4-dichlorophenol in aqueous solution by sono-Fenton method

This study presents the results of the Sono-Fenton process for the degradation of 2,4-dichlorophenol (DCP). The influential parameters such as H₂O₂, Fe²⁺ and pH for the Sono-Fenton process were investigated. Sono-Fenton method was found to be the best one for degradation efficiency of DCP when compared with that of the Fenton process. The optimum concentrations for the degradation of DCP using conventional Fenton’s method were found to be 20 mg/L of Fe²⁺ and 580 mg/L of H₂O₂ at pH 2.5. In the case of Sono-Fenton, the optimal concentrations were found to be 10 mg/L of Fe²⁺ and 400 mg/L of H₂O₂ at pH 2.5. Sono-Fenton method resulted in the reduction of required Fe²⁺ concentration (50%) and H₂O₂ concentration (31%). In addition, this method could be applicable even at pH 5.0 and a degradation efficiency of DCP was 77.6%. Kinetic studies for the degradation of DCP proved that the degradation of DCP tends to follow pseudo first order reaction and the rate constant was found to be 7 × 10⁻⁴ min⁻¹.     

超声波降解全氟丁酸水溶液

全氟丁酸(PFBA)作为全氟辛烷磺酸基化合物(PFOs)和全氟辛酸化合物(PFOA)的替代品,相对于PFOS和PFOA,因水溶解度更大和碳链短等特点造成PFBA更难处理和代谢[1-2].     

Degradation of methylene blue in aqueous solution by ozone-based processes

The aim of this study was to compare the efficiency of conventional ozonation and catalytic ozonation (ozone/activated carbon (O₃/AC) and ozone/TiO₂/activated carbon (O₃/TiO₂/AC)) in the degradation of methylene blue (MB) component from MB aqueous solution. The removal rates of color and chemical oxygen demand (COD_Cr) were assessed to screen the most appropriate oxidative process of MB treatment. In this experiment conditions, the color was completely disappeared in the presence of TiO₂/AC catalyst, after 40 min of reaction time. However, only ozone system still existed 11.8% MB in aqueous solution, while in case of O₃/AC system MB of 4.6% was not removed. In the COD removal experiment, the catalytic ozonation process showed a superior performance, compared to that of the conventional ozonation. COD removal efficiency was significantly promoted in the presence of catalysts such as AC and TiO₂. O₃/TiO₂/AC was found to be the most effective approach to eliminating the color and enhancing COD removal efficiency. The catalyst of TiO₂/AC was characterized by using transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS).     

臭氧/分子筛氧化降解水中微量的硝基苯

本文以硝基苯为目标反应物,对臭氧／分子筛氧化和臭氧氧化去除水中微量有机污染物的效果进行了比较。发现与单独的臭氧氧化相比,臭氧／分子筛氧化工艺可以提高水中硝基苯的降解效果。在本次实验条件下,单独臭氧氧化和臭氧／分子筛氧化对硝基苯的去除率都随着温度的升高而增加,随着pH值的升高越来越大;此外还考察了分子筛对硝基苯去除率的影响,初步分析了分子筛在臭氧氧化过程中的作用。     

Adsorption of chromium by activated carbon from aqueous solution

Adsorption isotherms of Cr(III) and Cr(VI) ions on two samples of activated carbon fibres and two samples of granulated activated carbons from aqueous solutions in the concentration range 20–1000 mg/l have been studied. The adsorption isotherms have been determined after modifying the activated carbon surfaces by oxidation with nitric acid, ammonium persulphate, hydrogen peroxide and oxygen gas at 350°C and after degassing at different temperatures. The adsorption of Cr(III) ions increases on oxidation and decreases on degassing. On the other hand, the adsorption of Cr(VI) ions decreases on oxidation and increases on degassing. The increase of Cr(III) and the decrease of Cr(VI) on oxidation and the decrease of Cr(III) and the increase of Cr(VI) on degassing have been attributed to the fact that the oxidation of the carbon surface enhances the amount of acidic carbon–oxygen surface groups while degassing eliminates these surface groups. Thus while the presence of acidic surface groups enhances the adsorption of Cr(III) cations, it suppresses the adsorption of Cr(VI) anions.