超声协同TiO2光催化降解氯苯废水的研究

以钛酸丁酯为原料，采用超声法制备了纳米TiO2，以该TiO2作为光催化剂，对模拟氯苯废水进行超声光催化降解研究，考察了TiO2的加入量、氯苯的初始浓度、溶液pH值、过氧化氢的浓度等对氯苯降解率的影响。结果表明，pH值对氯苯的超声光催化影响较小，H2O2的浓度、氯苯的初始浓度影响较大。在TiO2质量浓度为200mg／L、氯苯质量浓度为110．6mg／L、pH为7．0、反应时间为90min的条件下，氯苯降解率可达92．94％。探讨了氯苯TiO2光催化降解的机理，氯苯超声光催化降解的中间产物主要是邻氯苯酚和间氯苯酚。     

节能灯下Fe~0/H_2O_2/有机酸盐曝气体系处理结晶紫研究

利用固态零价铁取代传统液态铁离子催化剂,和双氧水发生类Fenton反应,并与低分子有机酸盐形成络合物,提高降解效率。构建节能灯Fe0/H2O2/有机酸盐曝气体系,探究不同p H、Fe0的加入量、H2O2的初始浓度、有机酸盐的初始浓度和温度及不同有机酸体系对结晶紫降解效果的影响,寻求在可溶态铁溶度较低的条件下的最佳适用条件。结果表明:在中性环境下,节能灯下Fe0/H2O2/有机酸盐曝气体系降解结晶紫溶液中,可溶态铁的浓度能控制在较低的范围内,且柠檬酸钠体系比草酸钠体系控制效果更好,在这种条件下,节能灯下Fe0/H2O2/有机酸盐(草酸钠/柠檬酸钠)曝气体系的最佳降解条件为:反应温度约为30℃,有机酸盐初始浓度为1 mmol/L,H2O2初始浓度分别为5.88 mmol/L和3.92 mmol/L,Fe0加入量为19 g和16 g。     

印染废水的光催化氧化的研究

本文通过光催化作用,废水的结构发生了根本变化,由有机大分子变成小分子,最终形成无机矿化物,如CO2等。本研究以曙红C20H6O5Br4Na2染料溶液的光催化降解为模型反应,探讨了曙红溶液的初始浓度、催化剂投加量、pH值、通气量等因素对光催化脱色降解效果的影响。研究结果表明,曙红染料在pH为2．23左右时降解较为适宜,染料初始浓度对脱色率的影响符合线性递减的规律,适宜的催化剂添加量为0．07g／L,通气量为0．6L／min左右。     

活性炭在气液串联放电反应器中的作用

对气液串联放电反应器中悬浮活性炭对降解有机污染物的影响及联合处理过程中活性炭的作用进行了研究。结果表明：46kV脉冲流光放电与5g／L水洗活性炭联合处理具有协同效应，甲基橙的降解率提高22％；与5g／L吸附饱和的活性炭联合处理，比单独脉冲放电处理降解率提高12．25％，说明活性炭在联合处理中不仅有吸附能力，而且还具有催化作用。在上述两种条件下分别加入5ml／L H2O2，对·OH的产生具有协同效应，不但提高了O3和UV的利用率，而且还有利于活性炭的再生。     

固体超强酸SO_4~(2-)/TiO_2-Fe_2O_3光催化降解含酚废水

采用固体超强酸SO42-/TiO2-Fe2O3为光催化剂,苯酚的光催化降解为模型反应,考察了pH值、苯酚初始浓度、催化剂投加量、光照距离、光照时间、助催化剂H2O2对光催化降解过程的影响。结果表明,苯酚初始浓度为50mg/L,催化剂投加量5g/L,光照距离11cm,光照时间为150min,降解率达61.29%,添加助催化剂H2O2后,反应60min,苯酚降解率达到85.12%。     

Fenton法深度处理化纤废水中的氧化作用和絮凝作用

采用Fenton高级氧化法深度处理化纤生化出水,考察其氧化作用和絮凝作用对有机物去除的贡献情况。结果表明：在控制初始pH值为3,c（Fe2＋）为7．0mmol／L,c（H2O2）为0．15mol／L时,COD总去除率可高达63％,其中氧化作用去除率为40．1％,絮凝作用去除率为22．9％。初始pH、c（Fe2＋）以及c（H202）的变化对氧化和絮凝作用影响显著,但在各个反应因素变化范围内氧化作用对COD去除率一直高于絮凝作用对COD去除率。     

以[mmim]DMP-甲醇为工质对的吸收式制冷循环研究

采用离子液体[mmim]DMP-甲醇作为吸收式制冷系统工质对,运用文献提出的[mmim]DMP-甲醇二元溶液经验方程进行制冷循环计算研究,并将此系统的工作压力、COP等与相同工况下的溴化锂-水、氨-水制冷循环进行比较。研究结果表明：[mmim]DMP-甲醇工质对制冷系统工作压力要求适中,COP稍高于NH3／H2O系统,低于H2O／LiBr系统;[mmim]DMP-甲醇溶液对金属无腐蚀,其适用范围要大于H2O／LiBr系统,具有一定的应用价值。     

超声协同Fenton体系氧化降解废水中的CCl_4

Fenton深度氧化技术用于污染物的降解,受到许多工艺条件的影响和制约,针对不同体系寻求各影响因素最优化的科学配置关系,具有重要的理论意义和应用价值。通过引入功率可调的超声波,采用正交设计法科学优化实验方案,详细考察了超声功率、Fe~(2+)浓度、H2O2浓度、温度和pH 5个因素对于Fenton体系氧化降解模拟污染水体中四氯化碳(CCl_4)的影响规律,判定了影响CCl_4降解效果的各因素之间的主次关系,确定了最优化的降解反应工艺条件,同时基于优选的工艺参数,验证了单一因素变化对降解效果的影响。结果显示:超声波协同的Fenton体系,同等条件下能够把CCl_4的降解率提高26.96%;协同降解CCl_4的优化反应条件为温度303K、pH=3、H2O2浓度20mmol/L、Fe~(2+)浓度2.50mmol/L及超声功率300W。此条件下,反应45min时,CCl_4的降解率可达到78.49%,明显高于不加超声处理的对比实验效果;该降解过程符合一级反应动力学特征,表观活化能为6.99kJ/mol。     

低温水解法优化制备光催化剂TiO_2

采用低温水解法制备纳米TiO2材料,并用所制备的材料光催化降解甲基橙溶液,以甲基橙的降解率作为评价指标,考察了水浴温度、水钛摩尔比和pH对TiO2光催化性能的影响,通过正交试验优化了制备条件。运用X-射线衍射(XRD),扫描电子显微镜(SEM)和傅里叶红外光谱(FT-IR)对制备的样品进行了表征。结果表明:pH对TiO2光催化性能的影响最大,水钛摩尔比次之,水浴温度影响最小;而且pH=2,r(H2O/TTIP)=80,T=60℃时,样品的光催化活性最高,8mg/L的甲基橙在紫外光下降解率达85%以上,在模拟自然光下降解率可达60%以上。     

共沉淀制备MnZn铁氧体前驱体粉的热力学分析

针对Me(Me=Fe2+、Mn2+、Zn2+)-NaOH-H2O体系、Me-NaOH-Na2CO3-H2O体系以及Me-NH4HCO3-NH3.H2O-H2O体系,根据最新的热力学数据及离子在水溶液中的存在形式,进行了最新的热力学计算,得到了各金属离子[Me]T与pH值之间的关系,并给出了不同条件下的log[Me]T-pH曲线,从而确定3种金属离子的共沉淀范围。结果表明,在Me-NaOH-H2O体系中,控制pH值在10.0～10.7之间,可以让3种金属离子共沉淀;在Me-NH4HCO3-NH3.H2O-H2O体系中,决定3种离子共沉淀范围的是Zn2+的完全沉淀范围,当[C]T=0.5mol/L、[N]T=0.75mol/L时,控制pH值在6.0～7.5之间,可满足三者的共沉淀要求;在Me-NaOH-Na2CO3-H2O体系中,当[C]T=0.5mol/L时,控制反应体系的pH值在6.3～10.6之间,就可以保证3种金属离子共沉淀,从而获得成分准确的前驱体粉料。     

Degradation of C.I. Reactive Red 2 (RR2) using ozone-based systems: comparisons of decolorization efficiency and power consumption

This study investigated the decolorization efficiency of C.I. Reactive Red 2 (RR2) in O3, O3/H2O2, O3/Fe3+, O3/H2O2/Fe3+, UV/O3, UV/O3/Fe3+, UV/O3/H2O2 and UV/O3/H2O2/Fe3+ systems at various pHs. The effective energy consumption constants and the electrical energy per order of pollutant removal (EE/O) were also determined. The experimental results indicated that the energy efficiency was highest at [H2O2]0=1000mg/l and [Fe3+]0=25mg/l. Accordingly, the H2O2 and Fe3+ doses in the hybrid ozone- and UV/ozone-based systems were controlled at these values. This work suggests that the dominant reactant in O3, O3/Fe3+ and O3/H2O2 systems was O3 and that in the O3/H2O2/Fe3+ system was H2O2/Fe3+. The experimental results revealed that the combinations of Fe3+ or H2O2/Fe3+ with O3 at pH 4 and of H2O2 or H2O2/Fe3+ with UV/O3 at pH 4 or 7 yielded a higher decolorization rate than O3 and UV/O3, respectively. At pH 4, the EE/O results demonstrated that the UV/O3/H2O2/Fe3+ system reduced 85% of the energy consumption compared with the UV/O3 system. Moreover, the O3/H2O2/Fe3+ system reduced 62% of the energy consumption compared with the O3 system. At pH 7, the EE/O results revealed that the UV/O3/H2O2/Fe3+ system consumed half the energy of the UV/O3 system.     

Oxidation of acidic dye Eosin Y by the solar photo-Fenton processes

Oxidation of acidic dye Eosin Y has been investigated with Fenton process and photo-Fenton process (solar light or artificial light source). With UV-Fenton process and Fenton, 42.5% and 21.3% of dye could be removed from the water, respectively. However, 94.1% of dye was removed in solar-Fenton in 90min. Based on solar-Fenton process, the effect of pH value and the concentration of dye, Fe(2+), H(2)O(2) as well as oxalic acid concentration on Eosin Y degradation efficiency were investigated. In 60min, 96% of Eosin Y was degraded when the pH value was 3.5 and the concentration of Fe(2+), H(2)O(2) and oxalic acid was 10mol/L, 600mg/L and 300mg/L, respectively. The Eosin Y degradation was dependent on the dye concentration. That is higher Eosin Y concentration resulted in lower degradation efficiency. Under the conditions of pH 3.5, the Eosin Y apparent kinetics equation was -dC/dt=0.000249[Eosin Y](0.78)[Fe(2+)](1.14)[H(2)O(2)](1.26). Meanwhile, this research also proved that oxalic acid could improve the photocatalytic efficiency in the solar-Fenton process.     

Oxidative decomposition of p-nitroaniline in water by solar photo-Fenton advanced oxidation process

The degradation of p-nitroaniline (PNA) in water by solar photo-Fenton advanced oxidation process was investigated in this study. The effects of different reaction parameters including pH value of solutions, dosages of hydrogen peroxide and ferrous ion, initial PNA concentration and temperature on the degradation of PNA have been studied. The optimum conditions for the degradation of PNA in water were considered to be: the pH value at 3.0, 10 mmol L(-1) H(2)O(2), 0.05 mmol L(-1) Fe(2+), 0.072-0.217 mmol L(-1) PNA and temperature at 20 degrees C. Under the optimum conditions, the degradation efficiencies of PNA were more than 98% within 30 min reaction. The degradation characteristic of PNA showed that the conjugated pi systems of the aromatic ring in PNA molecules were effectively destructed. The experimental results indicated solar photo-Fenton process has more advantages compared with classical Fenton process, such as higher oxidation power, wider working pH range, lower ferrous ion usage, etc. Furthermore, the present study showed the potential use of solar photo-Fenton process for PNA containing wastewater treatment.     

Oxidative degradation of diethyl phthalate by photochemically-enhanced Fenton reaction

A kinetic investigation into the photo-degradation of aqueous diethyl phthalate by Fenton reagent was conducted in this study. The obtained results showed the enhancement of diethyl phthalate (DEP) decomposition by UV irradiation with the Fenton reaction. It was found that H2O2 concentration, Fe2+ concentration, and aqueous pH value were the three main factors that could significantly influence the degradation rates of DEP. The highest degradation percentage (75.8%) of DEP was observed within 120 min at pH 3 in the UV/H2O2/Fe2+ system, with original H2O2 and Fe2+ concentrations of 5.00 x 10(-4) and 1.67 x 10(-4)mol L(-1), respectively. The present study provides an effective approach to the treatment of wastewater containing DEP.     

Pre-treatment of penicillin formulation effluent by advanced oxidation processes

A variety of advanced oxidation processes (AOPs; O3/OH-, H2O2/UV, Fe2+/H2O2, Fe3+/H2O2, Fe2+/H2O2/UV and Fe3+/H2O2/UV) have been applied for the oxidative pre-treatment of real penicillin formulation effluent (average COD0 = 1395 mg/L; TOC0 = 920 mg/L; BOD(5,0) approximately 0 mg/L). For the ozonation process the primary involvement of free radical species such as OH* in the oxidative reaction could be demonstrated via inspection of ozone absorption rates. Alkaline ozonation and the photo-Fenton's reagents both appeared to be the most promising AOPs in terms of COD (49-66%) and TOC (42-52%) abatement rates, whereas the BOD5 of the originally non-biodegradable effluent could only be improved to a value of 100 mg/L with O3/pH = 3] treatment (BOD5/COD, f = 0.08). Evaluation on COD and TOC removal rates per applied active oxidant (AOx) and oxidant (Ox) on a molar basis revealed that alkaline ozonation and particularly the UV-light assisted Fenton processes enabling good oxidation yields (1-2 mol COD and TOC removal per AOx and Ox) by far outweighed the other studied AOPs. Separate experimental studies conducted with the penicillin active substance amoxicillin trihydrate indicated that the aqueous antibiotic substance can be completely eliminated after 40 min advanced oxidation applying photo-Fenton's reagent (pH = 3; Fe(2+):H2O2 molar ratio = 1:20) and alkaline ozonation (at pH = 11.5), respectively.     

Photo degradation of methyl orange an azo dye by advanced Fenton process using zero valent metallic iron: influence of various reaction parameters and its degradation mechanism

Advanced Fenton process (AFP) using zero valent metallic iron (ZVMI) is studied as a potential technique to degrade the azo dye in the aqueous medium. The influence of various reaction parameters like effect of iron dosage, concentration of H(2)O(2)/ammonium per sulfate (APS), initial dye concentration, effect of pH and the influence of radical scavenger are studied and optimum conditions are reported. The degradation rate decreased at higher iron dosages and also at higher oxidant concentrations due to the surface precipitation which deactivates the iron surface. The rate constant for the processes Fe(0)/UV and Fe(0)/APS/UV is twice compared to their respective Fe(0)/dark and Fe(0)/APS/dark processes. The rate constant for Fe(0)/H(2)O(2)/UV process is four times higher than Fe(0)/H(2)O(2)/dark process. The increase in the efficiency of Fe(0)/UV process is attributed to the cleavage of stable iron complexes which produces Fe(2+) ions that participates in cyclic Fenton mechanism for the generation of hydroxyl radicals. The increase in the efficiency of Fe(0)/APS/UV or H(2)O(2) compared to dark process is due to continuous generation of hydroxyl radicals and also due to the frequent photo reduction of Fe(3+) ions to Fe(2+) ions. Though H(2)O(2) is a better oxidant than APS in all respects, but it is more susceptible to deactivation by hydroxyl radical scavengers. The decrease in the rate constant in the presence of hydroxyl radical scavenger is more for H(2)O(2) than APS. Iron powder retains its recycling efficiency better in the presence of H(2)O(2) than APS. The decrease in the degradation rate in the presence of APS as an oxidant is due to the fact that generation of free radicals on iron surface is slower compared to H(2)O(2). Also, the excess acidity provided by APS retards the degradation rate as excess H(+) ions acts as hydroxyl radical scavenger. The degradation of Methyl Orange (MO) using Fe(0) is an acid driven process shows higher efficiency at pH 3. The efficiency of various processes for the de colorization of MO dye is of the following order: Fe(0)/H(2)O(2)/UV>Fe(0)/H(2)O(2)/dark>Fe(0)/APS/UV>Fe(0)/UV>Fe(0)/APS/dark>H(2)O(2)/UV approximately Fe(0)/dark>APS/UV. Dye resisted to degradation in the presence of oxidizing agent in dark. The degradation process was followed by UV-vis and GC-MS spectroscopic techniques. Based on the intermediates obtained probable degradation mechanism has been proposed. The result suggests that complete degradation of the dye was achieved in the presence of oxidizing agent when the system was amended with iron powder under UV light illumination. The concentration of Fe(2+) ions leached at the end of the optimized degradation experiment is found to be 2.78 x 10(-3)M. With optimization, the degradation using Fe(0) can be effective way to treat azo dyes in aqueous solution.     

Oxidation of dichlorvos with hydrogen peroxide using ferrous ion as catalyst.

This study examines how Fenton's reagent (Fe2+ and H2O2) decomposed dichlorvos insecticide. Results showed that dichlorvos decomposed in a two-stage reaction. The first stage is a Fe2+/H2O2 reaction in which dichlorvos swiftly decomposed. In the second stage, dichlorvos decomposed somewhat less rapidly, and it is a Fe3+/H2O2 reaction. The detection of ferrous ions also supports the theory of the two-stage reaction for the dichlorvos oxidation with Fenton's reagent. The dissolved oxygen of the solution decreased rapidly in the first stage reaction, but it slowly increased in the second stage with a zero-order kinetics. The Fenton system decomposed dichlorvos most rapidly when the initial pH in the solution is 3-4. In addition, increasing the concentration of hydrogen peroxide or ferrous ions can enhance the decomposition of dichlorvos. Consequently, the relationship of rate constant (kobs), [H2O2] and [Fe2+] at initial pH 3 is determined as kobs = 2.67 x 10(4)[H2O2]0.7[Fe2+]1.2.     

Improvement of COD and color removal from UASB treated poultry manure wastewater using Fenton's oxidation

The applicability of Fenton's oxidation as an advanced treatment for chemical oxygen demand (COD) and color removal from anaerobically treated poultry manure wastewater was investigated. The raw poultry manure wastewater, having a pH of 7.30 (+/-0.2) and a total COD of 12,100 (+/-910) mg/L was first treated in a 15.7 L of pilot-scale up-flow anaerobic sludge blanket (UASB) reactor. The UASB reactor was operated for 72 days at mesophilic conditions (32+/-2 degrees C) in a temperature-controlled environment with three different hydraulic retention times (HRT) of 15.7, 12 and 8.0 days, and with organic loading rates (OLR) between 0.650 and 1.783 kg COD/(m3day). Under 8.0 days of HRT, the UASB process showed a remarkable performance on total COD removal with a treatment efficiency of 90.7% at the day of 63. The anaerobically treated poultry manure wastewater was further treated by Fenton's oxidation process using Fe2+ and H2O2 solutions. Batch tests were conducted on the UASB effluent samples to determine the optimum operating conditions including initial pH, effects of H2O2 and Fe2+ dosages, and the ratio of H2O2/Fe2+. Preliminary tests conducted with the dosages of 100 mg Fe2+/L and 200 mg H2O2/L showed that optimal initial pH was 3.0 for both COD and color removal from the UASB effluent. On the basis of preliminary test results, effects of increasing dosages of Fe2+ and H2O2 were investigated. Under the condition of 400 mg Fe2+/L and 200 mg H2O2/L, removal efficiencies of residual COD and color were 88.7% and 80.9%, respectively. Under the subsequent condition of 100 mg Fe2+/L and 1200 mg H2O2/L, 95% of residual COD and 95.7% of residual color were removed from the UASB effluent. Results of this experimental study obviously indicated that nearly 99.3% of COD of raw poultry manure wastewater could be effectively removed by a UASB process followed by Fenton's oxidation technology used as a post-treatment unit.     

硫脲改性Fe_3O_4/壳聚糖微球对Hg~(2+)的吸附性能

利用反相悬浮分散法制备Fe3O4/壳聚糖磁性微球,并经硫脲改性(TMCS)用于吸附水溶液中Hg2+。考察了pH值、温度的影响,以及吸附动力学和吸附等温线。结果表明,TMCS为球形,粒径80μm～250μm。TMCS对Hg2+的吸附量随pH值升高而增加,但随温度升高而下降;焓变(ΔH0=-12.93kJ/mol)为负,表明吸附放热;Gibbs自由能(ΔG0=-16.41kJ/mol～-17.22kJ/mol)为负,表明吸附能自发进行。等温吸附线可用Langmuir模型拟合,最大吸附容量2.69mmol/g;吸附动力学可用拟二级模型拟合,表明化学吸附为控速步骤。吸附Hg2+后的TMCS可用0.01mol/L的EDTA脱附,脱附率达91%。     

Effects of reaction conditions on nuclear laundry water treatment in Fenton process

This study presents the efficiency of Fenton process in the degradation of organic compounds of nuclear laundry water. The influence of Fe(2+) and hydrogen peroxide ratio, hydrogen peroxide dose, pH and treatment time were investigated. The degradation of non-ionic surfactant and other organic compounds was analysed as COD, TOC and molecular weight distribution (MWD). The most cost-effective degradation conditions were at H(2)O(2)/Fe(2+) stoichiometric molar ratio of 2 with 5 min mixing and H(2)O(2) dose of 1000 mg l(-1). With the initial pH of 6, the reductions of COD and TOC were 85% and 69%, respectively. However, the removal of the organic compounds was mainly carried out by Fenton-based Fe(3+) coagulation rather than Fenton oxidation. Fenton process proved to be much more efficient than previously performed ozone-based oxidation processes.