Treatment of simulated wastewater containing Reactive Red 195 by zero-valent iron/activated carbon combined with microwave discharge electrodeless lamp/sodium hypochlorite

A comparative study of treatment of simulated wastewater containing Reactive Red 195 using zero-valent iron/activated carbon （ZVI/AC）, microwave discharge electrodeless lamp/sodium hypochlorite （MDEL/NaCIO） and the combination of ZVI/AC- MDEL/NaCIO was conducted. The preliminary results showed the two steps method of ZVI/AC-MDEL/NaCIO had much higher degradation efficiency than both single steps. The final color removal percentage was nearly up to 100% and the chemical oxygen demand reduction percentage was up to approximately 82%. The effects of operational parameters, including initial pH value of simulated wastewater, ZVI/AC ratio and particle size of ZVI were also investigated. In addition, from the discussion of synergistic effect between ZVI/AC and MEDL/NaCIO, we found that in the ZVI/AC-MEDL/NaCIO process, ZVI/AC could break the azo bond firstly and then MEDLfNaCIO degraded the aromatic amine products effectively. Reversing the order would reduce the degradation efficiency.

二沉池出水造成的超滤膜污染在NaClO溶液中化学清洗效能研究

二沉池出水中含有大量微生物代谢产物,这些物质在采用超滤膜对二沉池出水进行深度处理时会产生严重的膜污染,NaClO溶液常用于化学清洗有机物及微生物造成的膜污染。该研究采用NaClO溶液对二沉池出水造成的超滤膜污染进行化学清洗,结合膜通量、膜表面形貌、官能团、主要元素组成在NaClO溶液清洗前后的变化深入分析了NaClO化学清洗膜污染的效能及对膜特性的影响。结果表明NaClO溶液化学清洗可高效去除膜污染并恢复膜通量,但会改变膜表面形貌及元素组成;清洗温度、清洗时间、初始pH及NaClO浓度都会对清洗效能产生影响,在近中性、常温条件下,将污染膜浸泡在100 mg/L NaClO溶液内2 h即可有效去除膜污染,且过度清洗会导致膜损伤。因此,采用NaClO溶液化学清洗二沉池出水造成的膜污染时,需要严格控制清洗条件以实现膜污染高效去除并减少对膜结构特性的影响。

Study on Influencing Factors and Kinetics of Removal of Ammonia Nitrogen from High Salinity Wastewater by Sodium Hypochlorite Oxidation

The influencing factors and kinetics of oxidative degradation of ammonia nitrogen in high salinity wastewater by sodium hypochlorite oxidation( Na Cl O) were studied. The results showed that the degradation process of ammonia nitrogen by sodium hypochlorite accorded with a pseudo first-order kinetics model,and the influencing factors included Na Cl O dosage,initial concentration of ammonia nitrogen,salinity,temperature,and so on. When Na Cl O dosage was 0. 6%( MCl∶ MN= 13. 76),the reaction rate constant was up to 0. 015 75 min^(-1). The higher the initial concentration of ammonia nitrogen was,the worse the effect of oxidation reaction was. When the initial concentration did not exceed 45 mg/L,the effect on oxidation reaction rate constant increased with the increase of the initial concentration. Low salinity had no effect on ammonia nitrogen oxidation.When salinity was higher than 2. 0%,the inhibition effect on ammonia nitrogen oxidation would increase,and the reaction rate constant decreased obviously with the increase of salinity. The improvement of reaction temperature was beneficial to ammonia oxidation degradation. As temperature increased from 10 to 35 ℃,the reaction rate constant rose from 0. 00188 to 0. 01043 min^(-1).

Generation of sodium hypochlorite (NaOCl) from sodium chloride solution using C/PbO_2 and Pb/PbO_2 electrodes

Two modified electrodes （Pb/PbO2 and C/PbO2） were prepared by electrodepositing a lead oxide layer on lead and carbon sub- strates. These modified electrodes were used as anodes for the generation of sodium hypochlorite （NaOC1） from sodium chloride solution. Different operating conditions and factors affecting the treatment process of NaOC1 generation, including current density, pH values, con- ductive electrolytes, and electrolysis time, were studied and optimized. By comparison the C/PbO2 electrode shows a higher efficiency than the Pb/PbO2 electrode for the generation of NaOC1.

Comparison of Decontamination Efficacy between the Rapid Hygrothermal Pasteurization and Sodium Hypochlorite Treatments

We developed a novel rapid hygrothermal pasteurization (RHP) method using saturated water vapor with a dew point of 100℃. The aim of this paper is to compare the effect of RHP treatment versus conventional sodium hypochlorite (NaClO) treatments on inactivation of natural mesophilic bacteria and quality attributes on fruits and vegetables. The RHP treatment was performed within a second by free-falling samples (cabbage, cucumber, carrot, bell pepper, pineapple and melon) through cylindrical processing chamber filled with steam. NaClO treatment was performed by washing samples with NaClO solution (100 mg/mL of free chlorine (pH 7), for 1 min). The RHP treatment showed a significantly higher inactivation effect than NaClO treatment on all tested samples. The RHP treatment had a slightly larger influence on color and vitamin C content than NaClO treatment in cabbage. Furthermore, the effects of treatment time and operated temperature were also determined using microbial model system. Elongation of treatment time did not significantly increase the microbial inactivation effect. Lowering of operated temperature by mixing air into steam tended to decrease the inactivation effect. From these results, RHP treatment could be used as an alternative method for decontaminating microorganisms on fruits and vegetables, except on leafy vegetable. In addition, it is suggested that microbial inactivation by RHP treatment was achieved through the initial condensation stage of water vapor on sample surface. By contrast, interfusion of air disturbed the effective condensation of water vapor.

Molybdenum removal from copper ore concentrate by sodium hypochlorite leaching

The removal of molybdenum from a copper ore concentrate by sodium hypochlorite leaching was investigated. The results show that leaching time,liquid to solid ratio,leaching temperature,agitation speed,and sodium hypochlorite and sodium hydroxide concentrations all have a significant effect on the removal of molybdenum.The optimum process operating parameters were found to be：time,4 h;sodium hydroxide concentration,10%;sodium hypochlorite concentration,8%;liquid to solid ratio,10：1;temperature,50℃;and, agitation speed,500 r/min.Under these conditions the extraction of molybdenum is greater than 99,9%and the extraction of copper is less than 0.01%.A shrinking particle model could be used to describe the leaching process.The apparent activation energy of the dissolution reaction was found to be approximately 8.8 kJ/mol.

Effects of Different Concentrations and Exposure Time of Sodium Hypochlorite on the Structural,Compositional and Mechanical Properties of Human Dentin

This study evaluated the effects of sodium hypochlorite（NaOCl） with different concentrations and exposure time on the structural, compositional and mechanical properties of human dentin in vitro. Sixty dentin slabs were obtained from freshly extracted premolars, randomly distributed into four groups（n=15）, and treated with 1%, 5%, 10% NaOCl and distilled water（control group）, respectively, for a total of 60 min. Attenuated total reflection infrared（ATR-IR） spectroscopy, Raman spectroscopy and X-ray diffraction（XRD） were carried out before, 10 min and 60 min after the treatment. Scanning electron microscopy（SEM） and flexural strength test were conducted as well. The results showed that dentins experienced morphological alterations in the NaOCl groups, but not in the control group. Two-way repeated-measures analysis of variance revealed that the carbonate：mineral ratio（C：M）, Raman relative intensity（RRI）, a-axis, c-axis length and full width at half maximum（FWHM） with the increase of time and concentration in the NaOCl groups were not significantly different from those in the control group（P〉0.05）. Nevertheless, the mineral：matrix ratio（M：M） increased and the flexural strength declined with the increase of concentration and the extension of time in the NaOCl groups（P〈0.05）. Additionally, it was found that the M：M and the flexural strength remained unchanged after 1% NaOCl treatment（P〉0.05）, and the morphology changes were unnoticeable within 10 min in 1% NaOCl group. These results indicated that NaOCl has no significant effects on the inorganic mineral of human dentin; but it undermines and eliminates the organic content concentration-and time-dependently, which in turn influences the flexural strength and toughness of dentins. In addition, an irrigation of 1% NaOCl within 10 min can minimize the effects of NaOCl on the structural and mechanical properties of dentin during root canal treatment.

Detection of <i>Para</i>-Chloroaniline Resulting from the Interaction between Sodium Hypochlorite and Chlorhexidine Analyzed by Mass Spectrometry

5.1% of sodium hypochlorite (NaOCl) mixed with 2% of chlorhexidine (CHX) forms a brown precipitate that corresponds to para-chloroaniline (PCA), whether PCA is formed after the combination of NaOCl, CHX, and ethylenediaminetetraacetic acid (EDTA) by means of electron impact (high resolution and interlaced scanning) and ionization by fast atom bombardment (FAB), was analyzed. The brown precipitate, showed signals 127 and 153 Da, corresponding to p-chloroaniline and p-chlorophenyl isocyanate, respectively. These results were analyzed and compared with signals from the interlaced scanning program and confirmed with high resolution mass spectrometry analysis and compared with the NIST database. The mass spectra of this precipitated after different days confirmed the evolution of byproducts with the presence of a peak m/z = 127, due to the decrease of the fragment m/z = 153, which disappeared after 180 days. A blue and a white precipitate were observed by the addition of CHX (2%) with or without polyethylene glycol, respectively, EDTA (17%) and NaOCl (5.1%) precipitates contain chlorhexidine (m/z = 505), but no PCA was detected. We confirmed that PCA is not formed directly as a byproduct of CHX oxidation, but through the formation of the para-chlorophenyl isocyanate intermediate, which degrades slowly to PCA.

New insights into enhancement of sodium hypochlorite on formation and properties of anodic films on Ti6Al4V alloy

Anodic films were successfully fabricated on Ti6A14V alloy by anodic oxidation method in an environmental friendly electrolyte with and without sodium hypochlorite. The anodic films were characterized by means of the scanning electron microscope （SEM） and energy dispersive spectrometer （EDS）. Results revealed that the addition of sodium hypochlorite leads to the ultrafast growth of oxide films, and results in the significant changes of morphology and thickness. The influence of sodium hypochlorite on formation and crystallization of oxide films as a function of anodizing time was discussed. Meanwhile, potentiodynamic electrochemical tests and dry sliding wear tests were performed to evaluate the corrosion resistance and tribological properties of oxide films. It was found that the oxide film fabricated with the existence of sodium hypochlorite had improved corrosion resistance and tribological properties than the one formed without sodium hypochlorite. Moreover, the effect mechanism of sodium hypochlorite on the growth rate and surface morphologies of oxide films during the anodizing process was discussed. It was found that hypochlorite ions participated in the reaction on anode which causes the rapid growth of oxide films and then affect the whole anodizing process.

Oxidation of Lingwu Coal Extraction Residue in Aqueous Sodium Hypochlorite under Mild Conditions

To investigate the structural features and provide an alternative method for high value-added utilization of coal, Lingwu coal was first extracted with organic solvent at room temperature. Then its extraction residue was oxidized in aqueous sodium hypochlorite(ASHC) under mild conditions. The effects of oxidation conditions, such as temperature, reaction time, the ratio of Lingwu coal extraction residue(LCER, g) to ASHC(m L) and p H value, on the product distributions and compositions were investigated. The results of gas chromatography/mass spectrometry(GC/MS) suggested that 53 kinds of methyl esterified products were detected in total, and benzene carboxylic acids were the main oxidation products, while chloro-substituted benzene carboxylic acids were the main by-products. Higher yield and fewer kinds of organic acids could be obtained at lower p H value, especially for the main objective product, benzene carboxylic acids.

雾化吸入NaClO致小鼠肺损伤模型的构建及机制研究

目的:建立次氯酸钠(NaClO)消毒剂诱导小鼠肺损伤模型,探讨其吸入毒性机制。方法:将0、75、150、300μg/L的NaClO溶液雾化成细微液滴给小鼠静态吸入染毒5 min,染毒后24 h使用肺功能仪检测小鼠肺功能,眼眶取血,收集肺泡灌洗液(BALF)和肺组织。采用HE染色观察肺组织结构,透射电镜观察肺组织细胞内线粒体等细胞器形态,TUNNEL染色观察肺组织细胞凋亡情况。BCA法测BALF蛋白浓度,流式细胞术检测BALF中细胞数量,Western blot检测肺组织抗氧化酶、凋亡及自噬相关蛋白的相对表达量,ELISA试剂盒检测血清、BALF和肺组织匀浆中炎症相关蛋白含量,qPCR检测肺组织匀浆炎症和抗氧化酶相关基因的mRNA表达水平,试剂盒检测肺组织匀浆中MDA含量和SOD酶活性。结果:与对照组相比,75μg/L NaClO染毒组小鼠肺BALF中蛋白浓度变化不明显,150和300μg/L NaClO染毒组BALF中蛋白浓度明显升高且细胞数量明显增多(均为P<0.05),故后续选择150μg/L NaClO作为研究浓度。与对照组相比,150μg/L NaClO染毒组肺功能损伤明显(P<0.05),肺组织匀浆中抗氧化酶SOD2和Nrf2的蛋白表达水平降低(P<0.05),SOD2、Nrf2、CAT mRNA的表达水平降低(P<0.05),肺组织中IL-1β和TNF-α在血清、BALF和肺组织匀浆中的浓度均升高(P<0.05),肺组织匀浆中IL-1β和TNF-αmRNA相对表达量升高(P<0.05),凋亡细胞数量明显增加,Bax和Cleaved caspase-3蛋白表达水平升高(P<0.05);且肺组织细胞线粒体明显肿胀,有自噬溶酶体出现,Beclin1蛋白表达水平升高(P<0.05),P62蛋白表达水平降低(P<0.01)。结论:成功建立了NaClO诱导小鼠肺损伤模型,并发现NaClO可诱导小鼠肺组织发生凋亡、氧化应激、炎症和自噬。

响应曲面法优化NaClO浸出贵州难浸金矿中的金

采用响应曲面法(RSM)优化NaClO浸出贵州难浸金矿中的金,探究了NaClO浓度、温度、液固比、pH值4个因素之间的交互作用及其对金浸金率的影响,并进行了参数优化。RSM分析表明,各因素对金浸出率的显著程度为:NaClO浓度>液固比>pH>温度,NaClO浓度和pH之间的交互作用较为显著;得到较优的浸金工艺条件为:反应时间3h,NaClO浓度0.9mol/L,初始pH=13.4,液固比8.2,温度27℃,在此条件下金的浸出率为93.4%。

NaClO重复清洗膜污染效能及卤代副产物生成研究

以过滤二沉池出水后受污染的超滤膜为研究对象,考察NaClO溶液对污染膜重复清洗后超滤膜的截留效果、NaClO的清洗效能及清洗过程中毒性副产物的累积情况。结果表明,NaClO溶液重复清洗会导致膜损伤,进而导致超滤膜对TOC和TP的截留率在NaClO溶液重复清洗6次后分别降低了65%和23%;同时膜通量恢复率随清洗次数增加整体呈现上升趋势。NaClO清洗液经多次使用后,剩余清洗液中大部分毒性氯代副产物会逐渐积累,如二氯乙酸(DCAA)、三氯乙酸(TCAA)、水合三氯乙醛(CH)、1,1-二氯丙酮(1,1-DCP)、二氯乙腈(DCAN)和三氯乙腈(TCAN);剩余清洗液中三氯甲烷(TCM)随着清洗次数增加呈现出先增高后逐渐稳定的趋势,而三氯乙烯(TCE)浓度则随清洗次数增加先增高后降低。

2.5%NaClO溶液冲洗对大鼠炎症牙髓愈合影响

目的评估使用2.5%NaClO溶液作为冲洗剂对大鼠炎症牙髓保存治疗后愈合的影响。方法选取24只8周龄雄性SD大鼠上颌磨牙48颗,采用髓腔暴露法穿髓暴露24 h制备牙髓炎症模型,然后切除部分冠髓,根据对牙髓切断后不同的冲洗处理方法分组,2.5%NaClO冲洗(NaClO)组和生理盐水冲洗(NS)组,均以iRoot BP Plus盖髓,窝洞用玻璃离子封闭。两组分别于术后第1、7、28天各处死4只动物,组织病理学观察评估剩余牙髓组织的炎症反应、组织破坏及硬组织的形成情况。结果2.5%NaClO组和NS组的牙髓炎症反应、组织破坏程度和修复性牙本质形成在术后第1、7、28天表现近似,两组间差异无统计学意义。结论在大鼠炎症牙髓模型上牙髓部分切断后运用2.5%NaClO作为iRoot BP Plus盖髓前冲洗止血剂与生理盐水表现出相似的作用,并不影响牙髓炎症的愈合。

Cu(Ⅱ)催化NaOCl氧化碘帕醇的效果和过程解析

本文研究Cu(Ⅱ)催化NaOCl氧化非离子型碘代X射线造影剂—碘帕醇(IPM),对IPM降解过程中Cu的回收和形态进行解析,考察Cu(Ⅱ)、NaOCl浓度和卤素离子对IPM降解效果及碘代消毒副产物-碘仿的生成影响;采用XRD、XPS分析Cu(Ⅱ)反应后的产物晶型和形态变化,结合循环伏安曲线和计时电流表征Cu(Ⅲ)的生成,推测Cu(Ⅱ)催化NaOCl氧化IPM的机理.利用HPLC/MS/MS分析中间产物,推测IPM的降解路径.结果表明,与Co(Ⅱ)、Fe(Ⅱ)、Mn(Ⅱ)相比,Cu(Ⅱ)显著提高了NaOCl的分解率和IPM的氧化效果,25℃、pH=6.71,500r/min,NaOCl和Cu(Ⅱ)浓度分别为0.5和0.05mmol/L,60min,8.0mg/L IPM的降解率达到77.51%;HO·、活性氯自由基和Cu(Ⅲ)都有助于Cu(Ⅱ)/NaOCl氧化IPM,且Cu(Ⅲ)的贡献随pH值升高而增大.NaOCl浓度在0.1~2.5mmol/L范围增加,IPM降解率增加;Cu(Ⅱ)浓度在0.005~0.5mmol/L存在适宜值.HPLC/MS/MS共检测出13种产物,IPM的降解途径主要包括:侧链酰胺键水解和氧化,碘取代、羟基加成.Cl^(−)、Br^(−)和I^(−)(1~5mmol/L)在影响IPM氧化效果的同时,Br^(-)显著促进了CHI_(3)的生成,生成量达到48.28μg/L.

70%乙醇去除弯曲根管内氢氧化钙的效果评价

目的:应用显微CT(micro-computed tomography,Micro-CT)评价不同冲洗液联合声波荡洗对后牙弯曲根管内氢氧化钙的清除效率。方法:收集2023年10月—2024年2月在上海交通大学医学院附属第九人民医院口腔综合科门诊拔除的磨牙20颗(根管数n=48),按照根管治疗标准流程,使用镍钛器械完成预备后,在根管内置入氢氧化钙。1周后,根据不同冲洗方法将样本随机分入6组(n=8),即先分为次氯酸钠组、17%EDTA组和70%乙醇组3组,每组再分为使用或不使用声波荡洗2个亚组。冲洗前、后使用Micro-CT重建根管系统,使用不同颜色标记独立根管,计算根管各段氢氧化钙体积,比较各组氢氧化钙清除率。采用SPSS 19.0软件包对数据进行统计学分析。结果:6组均无法去净根管内氢氧化钙,70%乙醇组去除氢氧化钙后剩余体积显著小于其余2组(P<0.05)。在乙醇亚组内,声波震荡组与注射器组去除效率无显著差异(P>0.05)。结论:70%乙醇能增加弯曲根管内氢氧化钙去除效率。

煤层H_(2)S与煤脱硫协同治理研究

为研究煤层H_(2)S与煤脱硫的协同治理,自制装置对复配碱液进行H_(2)S吸收和煤脱硫试验。采用离子色谱法、X射线光电子能谱、形态硫测试对吸收液和煤样进行表征,分析协同治理机理,利用响应面法分析各因素对H_(2)S吸收和煤脱硫的影响程度。结果显示:单一碱液均可吸收H_(2)S,但脱硫效果微弱;添加NaClO后,协同治理效果显著且能避免H_(2)S二次逸散,其中NaOH+NaClO协同治理效果最优。在反应后,H_(2)S及煤中低价态硫噻吩、硫醇和硫醚减少,吸收液中SO_(4)^(2-)及煤中高价态硫(亚)砜增加,表明NaOH为元素硫歧化提供碱性条件,元素硫继而被NaClO氧化。NaOH质量浓度对H_(2)S吸收影响最大,NaClO质量浓度对煤脱硫影响最大,NaOH和NaClO交互对煤脱硫与H_(2)S吸收影响显著。利用Design-Expert软件确定最佳参数:NaOH质量浓度为54 g/L、NaClO质量浓度为54 g/L、温度为21.4℃。

负载铁系金属氧化物催化次氯酸钠降解酸性大红的实验研究

酸性大红是一种性能良好的染料,也是一种难以治理的工业废水,但由于它在水中溶解度较高,通常难以通过简单方法直接进行处理。次氯酸钠为多功能强氧化剂,安全无毒,但稳定性不高,对氧化活性的利用不够,对酸性大红染料的去除能力有限。通过负载铁系金属氧化物来催化次氯酸钠对酸性大红染料进行降解,从而高效率提供分子反应动能,提高其氧化性;考察pH值、催化剂投入量、反应时间、次氯酸钠用量、负载催化剂量等对酸性大红的降解作用,得出最佳处理条件。结果显示:①采用沉淀—负载法,随着负载量增加,硅藻土图谱上的CoFe_(2)O_(4)峰越来越明显,完成了有效负载;②在pH值为4、反应时间为25 min、催化剂投加量为0.7 g、负载催化剂量达到30%、次氯酸钠溶液为5 mL时,降解酸性大红效果最显著;③对比次氯酸钠和芬顿试剂氧化降解酸性大红发现,次氯酸钠对酸性大红的去除率比芬顿试剂高;④在实际生产废水降解实验中,使用负载铁系金属氧化物催化次氯酸钠降解酸性大红和COD的效果十分显著,用此方法对废水中的酸性大红和COD的去除率分别为90%和83%。

粉煤灰-NaClO非均相催化氧化CN^-的研究

研究了利用电厂粉煤灰作为非均相催化剂,催化NaClO氧化CN-,讨论了各种因素对CN-去除率的影响.结果表明,在30℃,pH=2 5,NaClO和NaCN的起始浓度分别为0 40和0 15mol/L,反应时间为90min,粉煤灰的用量为6 0%的条件下,粉煤灰具有良好的催化活性,能有效地催化NaClO氧化CN-,CN-的去除率可达83%左右.该法可用于预处理焦化、制革、电镀行业含CN-的工业废水.

Ti基Ru-Ir-Ti电极在稀氯化钠溶液中的电解失效行为

金属钛电极具有高催化活性、高耐久性能、易加工生产等优点,可应用于氯碱工业、饮用水消毒、循环冷却水处理等方面,在许多领域拥有广阔的发展前景。然而,其失效机理大多在硫酸溶液中进行,不能真实反映电极在氯化钠环境下工作的实际状况。鉴于此,本工作采用电化学与表面物理方法对Ru-Ir-Ti电极在稀氯化钠溶液中的加速电解过程进行了研究。对加速电解不同阶段的研究表明:电极的失效是一个渐变过程,电解前期,涂层表面钌的溶解速率较快,之后电极呈现均匀腐蚀,活性物质Ru、Ir逐渐减少。涂层在表面和内部的电解消耗导致涂层疏松、结构被破坏,当活性物质减少到临界点时,起导电性的电催化活性物质缺失,反应进行缓慢,槽电压升高,这是电极失效的主要原因,研究过程尚未发现电极基底发生钝化现象。同时研究表明,电解产生的次氯酸钠不会对电极性能造成影响。