零价Mn促进Fe/C微电解反应速率及降解污染物机理

铁碳微电解工艺处理废水效率低,易出现板结问题,仅适用于处理酸性废水。为了扩宽铁碳微电解工艺的适用范围及提高处理效率,研究采用添加零价Mn构建Fe/Mn/C三元微电解体系处理甲基橙(MO)模拟染料废水。利用SEM-EDS、傅里叶红外光谱及拉曼光谱分析铁、锰和活性碳表面形貌的变化及元素组成,采用紫外可见光谱和三维荧光光谱等探究有机物成分的变化,对比Fe/Mn/C和Fe/C微电解体系对甲基橙的降解效果,揭示Fe/Mn/C三元微电解体系降解甲基橙的反应机理和反应动力学。结果表明：反应后的铁、锰、碳填料表面存在铁氧化物、氢氧化物及锰氧化物,Fe/Mn/C三元微电解可断裂甲基橙的氮氮双键,破坏苯环结构。甲基橙的降解过程符合二级反应动力学;Fe/C微电解体系加入零价Mn后,甲基橙降解的反应速率常数由5.7381×10_^-4 min_^?1提高至9.38336×10_^-4 min_^?1,降解速率和降解效果显著优于Fe/C微电解。     

Mn强化Fe/C微电解工艺条件优化及降解油墨废水机理

为了提高Fe/C微电解工艺对油墨废水的处理效率,以金属锰改变传统铁碳填料的成分,采用响应面法优化微电解工艺条件,通过三维荧光光谱、紫外可见光谱、气-质联用色谱等分析处理前后油墨废水的有机物成分及填料表面结构的变化,探究絮凝和降解机理。结果表明：在初始pH为2.79,反应时间为1.58 h,Fe/Mn质量比为3.11,填料总投加量为93.36 g/L的条件下,COD去除率达到87.9%,预测值(87.8%)与实测值相差0.1%,采用响应面法可准确预测COD去除率的变化。经Fe/Mn/C微电解工艺处理后,油墨废水Zeta电位上升,絮凝作用增强。Fe/Mn/C微电解工艺可破坏苯环及共轭双键结构,对类溶解性微生物代谢产物、类芳香族蛋白质类物质以及类腐殖酸类物质的降解效果显著,微电解过程中填料表面生成了铁、锰氧化物,部分氧化物附着在活性炭表面。     

改性活性半焦吸附-Fe/C微电解-Fenton联用技术处理焦化废水

采用改性活性半焦吸附-Fe/C微电解-Fenton联用技术处理焦化废水,探究联用技术工艺参数对焦化废水化学需氧量(COD)去除率的影响,结果表明:(1) 针对Fe/C微电解处理焦化废水的最佳操作条件为:pH=3,Fe与C质量比2.0∶1,Fe/C投加量30 g·L^-1,反应时间60 min,反应温度35 ℃;(2) 采用Fe/C微电解-Fenton氧化处理焦化废水最佳操作条件为:过氧化氢投加量25 mL·L^-1,pH=3,Fe与C质量比2.0∶1,Fe/C投加量30 g·L^-1,反应时间8 h。在最佳吸附-Fe/C-Fenton联用工艺条件下操作,对焦化废水COD降解率达到85.23%,COD由199.27 mg·L^-1降至29.43 mg·L^-1。动力学研究表明,动力学方程能很好的拟合Fe/C微电解降解过程。     

铁炭微电解与硫酸盐还原菌耦合修复铀尾矿库渗滤水的研究

设计了铁炭微电解-硫酸盐还原菌(Fe/C-SRB)、铝炭微电解-硫酸盐还原菌(Al/C-SRB)、炭-硫酸盐还原菌(C-SRB)、铁炭微电解(Fe/C)、铝炭微电解(Al/C)和炭(C)6个反应器,并研究了它们修复铀尾矿库渗滤水中U、Mn、Zn、SO₄^2-以及NO₃^-的效果。结果显示：经过2.5 h,Fe/C-SRB系统出水U浓度降至0.05 mg/L以下;1 d后,Mn浓度降至10 mg/L以下;1 d后,Zn浓度降至0.05 mg/L以下;10 d后,SO₄^2-浓度降至50 mg/L以下;18 d后,NO₃^-浓度降至10 mg/L以下,均达到了相关国家排放标准,并运行稳定,处理效率显著高于其他反应器。60 d时,Fe/C-SRB系统填料中具有还原U(Ⅵ)功能的微生物Desulfotomaculum、Desulfovibrio和Desulfosporosinus群落丰度总和达到61.45%,与Al/C-SRB、...     

臭氧/过硫酸氢钾体系降解酮洛芬的动力学研究

利用臭氧/过硫酸氢钾体系降解酮洛芬模拟废水,考察了不同反应温度、初始浓度、初始p H值下酮洛芬的降解动力学,并拟合表观动力学方程;采用竞争法,以硝基苯和苯甲酸为分子探针,测定酮洛芬与硫酸根自由基的二级反应速率常数。结果表明,不同实验条件下酮洛芬降解符合准一级动力学,通过对实验数据进行拟合得到表观动力学方程k=494296exp（-31494/RT） C₀^-0.3677[OH^-]^0.1478,酮洛芬与硫酸根自由基的二级反应速率常数为1.49×10⁹M^-1s^-1。     

UV-LED/NaClO工艺降解水中邻苯基苯酚的活性组分贡献和影响因素

采用紫外发光二极管协同次氯酸钠(UV-LED/NaClO)工艺对水中邻苯基苯酚(OPP)去除进行研究,以硝基苯(NB)、苯甲酸(BA)和二甲氧基苯(DMOB)为探针物质,采用竞争动力学确定了UV-LED/NaClO工艺中HO·、Cl·和ClO·的稳态浓度及其与OPP的二级反应速率常数,研究OPP降解过程中不同组分的贡献,考察NaClO投加量和pH对OPP去除及不同组分贡献的影响。结果表明：UV-LED/NaClO可以有效降解OPP,其降解拟一级动力学常数为0.275 2 min^-1(拟合优度R²=0.993 4)。当NaClO投加量为3 mg·L^-1时,HO·、Cl·和ClO·稳态浓度分别为1.22×10^-13、1.08×10^-14和1.38×10^-12 mol·L^-1,其与OPP的二级反应速率常数分别为1.86×10⁹、1.33×10¹¹和2.18×10⁸ L·mol...     

热解时间对污泥生物炭活化过硫酸盐的影响研究

污泥热解制备生物炭是一种污泥有效处理处置与资源化利用方法。通过控制热解时间,调控污泥生物炭表面的活性位点,改变过一硫酸盐（PMS）体系中的活性物种组成,可实现环丙沙星（CIP）的高效降解。研究发现,热解温度为700℃、热解时间为120 min时,污泥生物炭具有较高的PMS活化性能,对CIP的去除率近90%。机理探究表明,¹O₂在体系中发挥主要作用。C==O、吡咯氮和—OH位点有利于¹O₂产生,C—O、吡啶氮、晶格氧和Fe位点促进·OH和SO₄^·-释放,石墨氮可促进PMS活化产生SO₄^·-。     

UV/oxone降解水中甲氧苄啶的效能及模型评价

研究采用UV、oxone、UV/oxone共3种工艺降解甲氧苄啶（TMP）的效果及动力学。采用响应面曲线法研究含有HCO₃ ^-、Cl^-、NO₃ ^-和pH四因素、三水平的水体条件下UV/oxone对TMP的降解效果及模型，并选用4种实际水源水体为水质背景来评价模型预测值与实际降解值的差别，最后比较了3种工艺的同等降解率条件下的降解效能。结果发现UV和oxone单独降解TMP时仅降解了5.5%和62.0%，而UV/oxone可达到93.2%，且降解过程符合拟一级反应动力学，动力学常数为0.1768min^-1。采用相对速率法可得到?SO₄ ^–与TMP的反应速率常数为2.07×10⁸L/(mol·s)。通过响应面曲线法得到UV/oxone降解TMP的回归方程式，对应的p值小于0.0001，拟合缺失项P不显著（0.9726>0.05），校正决定系数R ²=0.82＞0.8，说明该模型可信度高，采用实际水体进行模型验证后发现实际降解值基本符合模型预测值。降解率一定的条件下UV/oxone耗时最短，是一种高效、快速、可行的降解工艺。     

芦竹燃烧动力学不同反应机理的研究

利用热重分析仪进行了芦竹的燃烧试验,采用Coats-Redfern法分析热重曲线,研究不同升温速率(10,20,30℃/min)对燃烧过程的影响。结果表明,芦竹燃烧过程可分为3个阶段,即水分析出、挥发分析出与燃烧及焦炭表面燃烧三个阶段。主要反应集中在第二和第三反应阶段。随着升温速率的增大,最大失重速率增大,三个阶段向高温方向偏移。挥发分析出与燃烧及焦炭表面燃烧阶段的反应机理均满足随机成核A3模型,挥发分析出及燃烧阶段的活化能平均值为21.49 k J/mol,频率因子变化为1.31×10³3¹.83×101.83×10³min3min^(-1);焦炭表面燃烧阶段的活化能平均值为47.15 k J/mol,频率因子变化为325×10(-1);焦炭表面燃烧阶段的活化能平均值为47.15 k J/mol,频率因子变化为325×10³3⁷4.9×1074.9×10³min3min^(-1)。     

基于热重分析的（Al2O3–C）/Fe体系的反应动力学EI北大核心CSCD

借助于热分析仪,通过热重分析研究了（Al2O3–C）/Fe体系中的反应动力学特征。在氩气气氛和不同升温速率下,对（Al2O3–C）/Fe试样进行了热重实验。计算出不同阶段反应的活化能Ea、指前因子A和反应速率常数k,同时,提出了（Al2O3–C）/Fe体系反应的2个阶段,铁熔化前为第1阶段,主要是氧化铝和碳之间的固–固反应,铁熔化后为反应的第2阶段,主要为固–液反应阶段。在高温条件下,铁液的参与使得反应速率加快,促进了氧化铝碳热还原反应的进行。     

Low-Temperature SCR of NO with NH3 over USY-Supported Manganese Oxide-Based Catalysts

A series of catalysts of manganese oxide, manganese–cerium and iron–manganese oxide supported on USY (ultra-stable Y zeolite) were studied for the low-temperature selective catalytic reduction (SCR) of NO with ammonia in the presence of excess oxygen. It was found that MnO_x/USY have high activity and high selectivity to N₂ in the temperature range 80-180 °C. The addition of iron and cerium oxide increased NO conversion significantly although the single-component Fe/USY and Ce/USY catalysts had low activities. Among the catalysts studied in this work, the 14% Ce-6% Mn/USY showed the highest activity. The results showed that this catalyst yielded nearly 100% NO conversion at 180 °C at a space velocity of 30 000 cm³ g^-1 h^-1. The only product is N₂ (with no N₂O) below 150 °C. The effects of the concentration of oxygen, NO and NH₃ were studied and the steady-state kinetics were also investigated. The reaction order is 1 with respect to NO and zero with respect to NH₃ on the 14% Ce-6% Mn/USY catalyst at 150 °C.     

Comparison of catalytic ozonation of phenol by activated carbon and manganese-supported activated carbon prepared from brewing yeast

Activated carbon (AC) was prepared using brewing yeast as precursor by chemical activation and manganese was supported on activated carbon (Mn/AC) by adsorption-activation method. The characterizations of prepared AC and Mn/AC and their performance as ozonation catalysts was tested. The results indicated that the crystalline phase of supported manganese was MnO. The total BET surface areas of prepared AC and Mn/AC were found to be 1603.0 m²/g and 598.9 m²/g, with total pore volumes of 1.43 and 0.49 cm³/g, respectively. The average pore diameters of AC and Mn/AC were found to be 3.5 nm and 3.3 nm. Adsorption capacities of phenol onto the produced AC and Mn/AC were determined by batch test, at 25 °C and pH 7. Langmuir and Freundlich isotherm models were used to fit the isotherm experimental data, and the Langmuir isotherm model fitted these two adsorption systems well. The maximum uptakes of phenol by AC and Mn/AC were estimated to be 513.5 mg/g and 128.2 mg/g. The presence of AC prepared from brewing yeast was advantageous for TOC reduction of phenol solution compared with single ozonation, and the greatest TOC removal efficiency was obtained in the presence of Mn/AC. All ozonation reactions followed the pseudofirst-order kinetics model well, the degradation rate of phenol was enhanced in the presence of catalysts, and the more pronounced degradation rate was achieved in O₃/Mn/AC system. The rate constants were determined to be 2.16×10⁻² min⁻¹ for O₃ alone, 5.70×10⁻² min⁻¹ for O₃/AC and 6.82×10⁻² min⁻¹ for O₃/Mn/AC.     

US/Fe~(3+)/H_2O_2体系超声催化降解甲基橙的研究

采用US/Fe3+/H2O2体系超声催化降解甲基橙,考察了超声波功率、Fe3+初始质量浓度、H2O2用量、甲基橙溶液的初始质量浓度及初始pH值对超声催化降解甲基橙的影响,初步探讨了其降解动力学规律。结果表明,US/Fe3+/H2O2体系能有效降解甲基橙,且超声波与Fenton试剂对甲基橙废水的降解存在强烈的协同作用;在pH=3、超声波功率500 W、Fe3+和H2O2的初始质量浓度分别为30 mg/L和150 mg/L时,对含30 mg/L的甲基橙溶液降解120 min,其去除率达到99.5%;甲基橙的超声催化降解符合一级反应动力学规律,且甲基橙的一级反应速率常数随其初始质量浓度增大而降低。     

Catalytic wet peroxide oxidation of phenol solution over Fe–Mn binary oxides diatomite composite

Mn–Fe binary oxides incorporated into diatomite (denoted as FM-diatomite) was prepared by the redox reaction of KMnO₄ and FeSO₄ with pH ranging from 3 to 9. The catalytic activities of FM-diatomite were studied for phenol oxidation and were compared with iron oxide modified diatomite (F-diatomite) and manganese oxide modified diatomite (M-diatomite). The obtained catalysts were characterized by scanning electron microscope, powder X-ray diffraction, energy dispersive spectroscopy, transmission electron microscope, X-ray photoelectron spectroscopy, and nitrogen adsorption/desorption isotherms. The results show that Fe–Mn binary oxides were highly dispersed on the diatomite surface in which manganese oxide and iron oxide displayed multiple oxidation states including Mn⁴⁺, Mn³⁺, Fe²⁺ and Fe³⁺. The phenol oxidation by H₂O₂ through the use of Mn–Fe-diatomite as a catalyst was conducted. FM-diatomite exhibited as an excellent catalyst for the total oxidation of phenol and main intermediates (catechol and hydroquinone). The conversion of phenol and main intermediates by means of FM-diatomite was 100 % under 50 min while that by F-diatomite also was 100 % after 110 min but other intermediates still remained. While phenol conversion by M-diatomite was close to zero due to speedy hydroperoxide decomposition over the manganese oxide catalyst. These results show that there was a synergized effect of iron and manganese oxide present in FM-diatomite.     

Synthesis of AgBiS2/gC3N4 and its application in the photocatalytic reduction of Pb(II) in the matrix of methyl orange,crystal violet,and methylene blue dyes

The removal of lead ions in contaminated water by the reduction of Pb(II) ions to the useful metallic Pb is challenging, especially in water polluted by other contaminants such as dye molecules. Most investigations focussed on the removal of Pb(II) in a single system. In reality, contaminated water contains a mixture of organic pollutants and heavy metals. Herein, we synthesized graphitic carbon nitride functionalized with ternary silver bismuth sulphide (AgBiS₂/gC₃N₄) for the photocatalytic removal of Pb(II) from dye-containing water. The as-synthesized gC₃N₄, AgBiS₂, and AgBiS₂/gC₃N₄ composite were characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), and transmission electron microscopy (TEM). The composite was used for the photocatalytic reduction of Pb(II) in the matrix of methyl orange, crystal violet, and methylene blue. The effect of the presence of easily-oxidizable organics and persulphate on the photocatalytic reduction of Pb(II) was also investigated. The results revealed that the presence of easily-oxidizable organics has synergistic effects on the photocatalytic reduction of Pb(II), while persulphate displayed inhibitive effect on Pb(II) reduction. The removal of Pb(II) in the dyes matrix was influenced by the type of dyes that were present in the water. The rate of Pb(II) reduction was reduced in the presence of methylene blue and methyl orange, but crystal violet displayed synergistic effects. Finally, the rate of degradation of dyes in the presence of Pb(II) was investigated. The rate of photocatalytic reduction of Pb(II) decreased from 0.0045 min^?1 to 0.0036 min^?1 and 0.0016 min^?1 in the matrix of methyl orange and methylene blue respectively. On the contrary, there was an increase in the rate of photocatalytic reduction of Pb(II) from 0.0045 to 0.0096 min^?1 in the matrix of crystal violet.     

Fe/C微电解法处理甲基紫染料废水

利用Fe/C固定床反应器,对Fe/C微电解法处理甲基紫染料废水的反应进行了研究。考察了进水pH值、进水流量、微电解反应柱中的Fe/C体积比、反应时间对处理效果的影响。结果表明,Fe/C微电解法可较好地处理甲基紫染料废水,甲基紫染料去除率高,脱色率好,最佳工艺条件为:进水pH值3.19,水流量为0.16 mL/s,微电解反应柱中的Fe/C体积比为1∶2,反应时间为3.5 h,甲基紫的去除率可达98.2%。     

超声波/铁-炭微电解耦合处理直接大红4BE染料废水

对超声波/铁-炭微电解耦合处理直接大红4BE染料废水进行了研究。结果表明,超声波与铁-炭微电解耦合可产生协同效应,4BE染料废水的去除率可超过90%,理论分析了协同机理。4BE染料废水的去除过程经历了快反应和慢反应两个阶段,两阶段均符合零级动力学模型,速率常数分别为3.56×10-2nmol/min和3.88×10-3nmol/min。反应主要受到溶液pH的影响,pH为2.4时有利于4BE的去除。