Fenton试剂高级氧化法降解甲基橙模拟废水研究

甲基橙是一种较难降解的有机苯环偶氮染料之一，研究其降解性能对其他染料废水体系的降解研究具有普遍参考价值。通过研究Fenton试剂降解甲基橙过程中的H202浓度、Fe2＋浓度、反应时间和反应体系pH值对甲基橙降解的影响，确定其最佳降解工艺条件为：当甲基橙浓度为20mg／L、pH值为3、Fe2＋浓度为1．5mmol／L、H2O2为32mmol/L时，降解率达到最大值（98．95％）。     

掺杂型二氧化钛纳米管光催化降解甲基橙研究

利用本实验室制备的N-F原子掺杂二氧化钛纳米管作催化剂,在可见光区对甲基橙(MO)进行光催化降解实验。在催化剂用量固定为3cm2时考察了不同初始浓度、pH值、溶解氧(DO)等对降解率的影响。结果表明,在可见光区该催化剂具有较高的光催化活性;当溶液DO为19.2mg/L、pH值为3、初始浓度为10mg/L、反应时间300min时,降解率可达82.3%。     

活化过硫酸钠预氧化-微生物降解联合修复石油烃污染土壤

为探究化学氧化法与微生物法联合修复技术在石油污染土壤修复中应用的可行性,文章采用联合修复实验,以过硫酸钠/过氧化钙为氧化剂,氧化预处理后联合生物修复,研究了修复过程中土壤石油烃含量、pH值、微生物数量以及石油烃分子分布的变化规律,比较了联合修复技术与单一生物修复对石油烃污染土壤修复效果的影响。实验结果表明,在过硫酸钠投加量0.3 mmol/g,n(Na₂S₂O₈):n(CaO₂):n(FeSO₄):n(柠檬酸)为5:5:1:1条件下,石油烃(C₁₀～C₄₀)降解率为24.41%,其中C₁₀～C₂₅组分石油烃的降解率为-6.82%,C₂₆～C₄₀组分石油烃降解率为31.34%,氧化预处理后土壤添加石油烃降解菌进行生物修复,经联合修复后土壤中石油烃降解率可达85.13%,比直接进行生物降解的土壤,生物降解率提高了39.66%。修复后土壤的pH值由9.3...     

P-25纳米TiO2在含酚废水处理方面的应用

采用室内模拟研究,以P-25纳米TiO2作为光催化剂进行了苯酚水溶液的光催化降解性能探讨,初步考察了溶液的pH、P-25纳米TiO2用量对光催化降解苯酚过程的影响,以获得P-25纳米TiO2光降解含酚废水的较好反应条件.实验结果表明,当溶液pH=8时,降解水体中苯酚效果最佳,强酸和强碱条件均不利于苯酚的降解;在pH 8的反应体系中,当光催化剂用量为0.4g/L时,催化水体中苯酚降解的效果最好.     

HPA／ZnFe2O4-TiO2光催化剂的制备及对马拉硫磷的可见光降解

以纳米TiO2载体，利用浸渍法制备了HPA／ZnFe2O4-TiO2光催化剂。对制备的催化剂进行了XRD、BET、TEM和UV-vis DRS表征。结果表明，催化剂样品均为锐钛矿相且ZnFe2O4很好地分散在载体表面，HPA／ZnFe2O4-TiO2光催化荆的平均粒径为10nm且在380-670nm均有强的光响应；反应最佳的HPA浓度为O.08molfL，最佳的ZnFe2O4负载量为1％。考察了HPA溶液初始浓度、ZnFe2O4负载量、溶液初始pH值、H2O2用量、催化剂用量对催化剂活性的影响。在溶液初始pH=13，H2O2=6mmol／L，催化剂用量为2g/L的最优条件下，光照反应进行100min后，马拉硫磷的降解率可达87％；重复4次后马拉硫磷的降解率仍可以达到67％。     

高硫酸盐木糖废水厌氧动力学研究

本文在中温 35± 1℃条件下 ,对含高浓度硫酸盐的木糖生产废水进行了厌氧消化动力学研究 ,分别研究了硫化物、pH值和COD/SO42 -的比值对COD降解动力学参数的影响。研究得出Monod模式的COD降解动力学参数变化范围为 :Vmax=0 2 382～ 0 460 2 (d-1 ) ,Ks=4330 90～ 6352 2 2 (mg/L)。     

TiO2光催化降解有机颜料艳红RGS母液研究

以TiO2为催化剂,对有机颜料艳红RGS母液进行了一系列光催化降解试验.考察了催化剂用量、溶液pH值、初始浓度、不同光源和照射时间对脱色率的影响.结果表明,溶液相对初始浓度为0.2、pH<8、催化剂用量为1g/L时,以紫外灯(254nm)为光源,反应120 min,脱色率可达93%以上.     

石墨相氮化碳降解水中氨氮

利用石墨相氮化碳降解水中氨氮,并对该材料降解氨氮的效果进行考察。探究了在氙灯照射下,不同初始pH以及不同初始氨氮含量条件下对氨氮降解的影响。结果表明：在氙灯照射下,当初始pH=12,初始氨氮含量为7.5μg时,石墨相氮化碳对氨氮具有良好的降解效果;当初始pH=13时,控制初始氨氮含量为7.5μg,光催化2 h后,氨氮去除率为95.68%。采用伪一级动力学模型进行研究,石墨相氮化碳在碱性条件下对氨氮有良好的降解速率,可能归因于随着初始pH的增大,溶液中存在更多的OH-和·OH,从而增强光催化效果。     

三氟乙酸(TFA)促进光催化降解水环境中甲基橙的研究

探讨了BiVO_4-BiIO_3光催化剂(BVBI)降解水体中有机污染物(甲基橙为模拟污染物)过程中,体系中的助剂三氟乙酸(TFA)的促进效果及理论机理。实验结果表明,TFA可明显提高光催化降解甲基橙的效率:反应0.5 h后加入0.25 m L TFA后降解率达到92.58%,而不加TFA降解率仅为25.50%。借助电化学分析与自由基捕获实验,我们推测TFA的助催化机理在于其有效地捕获催化剂的光生空穴(h+),促进其与光生电子(e-)的分离,提高e-利用率从而提高催化降解有机物的能力。首次利用TFA为光生空穴h+的捕获剂以提高光催化反应效率,研究成果可为光催化助剂高效降解水体中有机污染物的相关研究提供有益的借鉴。     

生物流化床处理生活污水的动力学研究

本研究采用颗粒活性炭（Granule Activated Carbon,GAC）为填料,考察了生物流化床（Biological fluidized Bed,BFB）处理生活污水的动力学.研究结果表明,GAC-BFB内生物膜的表现产率YoA为2.3057gVSS/gCOD,微生物细胞衰减常数Kd为0.3056d-1;基质降解动力学中米氏常数Ks为0.2182mg/L,反应速率常数K为13.09 mg/（l·h）.GAC-BFB的微生物生长动力学拟合方程为1/θc=2.3057q-0.3056,R2=0.9549; GAC-BFB的基质降解动力学拟合方程为1/U =0.2182＊1/S ＋0.0764,R2 =0.9972,该微生物生长动力学拟合方程及基质降解动力学拟合方程能较好的反映GAC-BFB系统的出水水质状况,本研究所获得的动力学关系和动力学参数可作为GAC-BFB系统的设计依据.     

弱磁场强化零价铁对水中偶氮染料脱色降解的作用初探

本文以橙黄Ⅰ、橙黄Ⅱ、橙黄Ⅳ和日落黄4种偶氮染料为目标染料,首次尝试利用外加弱磁场(~20 mT)的方法来强化零价铁脱色降解偶氮染料。结果表明加磁或不加磁时反应过程均符合一级反应动力学。在磁场的存在下,4种偶氮染料的降解速率都较不加磁场时有很大的提高,提高倍数分别为110.67、111.97、59.51和94.00。弱磁场对零价铁降解偶氮染料的促进作用可能是由于外加磁场所产生的洛伦兹力以及零价铁表面产生的感应磁场所产生的磁场梯度力促进了Fe2+的释放,加快了零价铁的腐蚀,促进零价铁释放更多电子和新生态氢,加速了—N=N—键的断裂,从而强化了染料的脱色降解。     

Heavy metals extraction from contaminated soil: recovery of the flushing solution

The optimum conditions for the recovery of copper from a contaminated soil by using the soil flushing technique are evaluated. Tests on a soil artificially contaminated with copper chloride were carried out in order to evaluate the influence of the speed of percolation and of the chelating agent concentration (aqueous solution of an ethylendiaminotetraacetic acid di-sodium salt Na2-EDTA). At pH=7.3 an efficiency up to 93.9% for copper extraction was achieved by flushing 500 ml of Na2-EDTA 0.05 M solution and 100 ml of pure water at 0.792 cm/h. At these operating conditions the formation of EDTA complexes with other competitive cations (calcium and iron) was negligible. The experimental results were in agreement with the ones obtained using a model describing the chemistry of metal extraction. This model assessed that above pH=6 the formation of calcium and iron EDTA complexes was excluded and only the chelation of copper was allowed. The recovery of 91.6% of EDTA was also achieved by evaporating and acidifying the extracted solution: after filtration, solid EDTA was obtained, through the addition of sodium hydroxide Na2-EDTA. About 99.5% of the extracted copper was finally precipitated under alkaline conditions from the liquid phase.     

Decolorization and Complete Degradation of Methyl Red by a Mixed Culture

Synthetic dyes, azo dyes in particular, are widely found in the effluents from textile industries. The persistence and toxicity of these compounds cause adverse impacts in the receiving streams. A mixed culture isolated from a domestic wastewater treatment plant was found to remove the colour of the azo dye, methyl red, efficiently. Total decolorization and degradation occurred within 18 h. The mixed culture could degrade 700 mgl^–1 of methyl red efficiently in the presence of 200 mgl^–1 of glucose, whereas in the absence of glucose it could degrade only 100 mgl^–1 of methyl red. The mixed culture, when suspended in phosphate buffer along with methyl red at 100 mgl^–1 concentration could degrade methyl red efficiently within 2 h of incubation. The pH of the medium decreased continuously during degradation. After the complete removal of initial methyl red, another 100 mgl^–1 was added to the culture filtrate and incubated further. The mixed microbial cultures could degrade methyl red efficiently through three cycles but further degradation was not possible as the pH of the medium decreased to 3.5.     

UV-H_2O_2联用工艺去除水中阿特拉津的研究

采用间歇式反应器考察了UV-H2O2高级氧化技术去除水中阿特拉津的效果及其影响因素,并进行了相关的反应动力学研究。结果表明,在pH值6.9,阿特拉津初始浓度500μg/L,紫外辐照强度172μW/cm2时,H2O2投加量50mg/L,反应10min后,阿特拉津的去除率90%。UV-H2O2联用工艺对阿特拉津的降解符合一级反应动力学。H2O2在该联用工艺降解阿特拉津中具有双重作用,一方面,当H2O2投加量较小时,一级反应速率常数随H2O2投加量的增加基本呈现线性增加的趋势;另一方面,当H2O2浓度增加到一定程度(90mg/L)后,阿特拉津的降解速率随H2O2浓度的变化已不明显,而H2O2浓度为102mg/L时,则出现了抑制作用。     

Degradation of soil fumigants as affected by initial concentration and temperature

Soil fumigation using shank injection creates high fumigant concentration gradients in soil from the injection point to the soil surface. A temperature gradient also exists along the soil profile. We studied the degradation of methyl isothiocyanate (MITC) and 1,3-dichloropropene (1,3-D) in an Arlington sandy loam (coarse-loamy, mixed, thermic Haplic Durixeralf) at four temperatures and four initial concentrations. We then tested the applicability of first-order, half-order, and second-order kinetics, and the Michaelis-Menten model for describing fumigant degradation as affected by temperature and initial concentration. Overall, none of the models adequately described the degradation of MITC and 1,3-D isomers over the range of the initial concentrations. First-order and half-order kinetics adequately described the degradation of MITC and 1,3-D isomers at each initial concentration, with the correlation coefficients greater than 0.78 (r2> 0.78). However, the derived rate constant was dependent on the initial concentration. The first-order rate constants varied between 6 and 10x for MITC for the concentration range of 3 to 140 mg kg(-1), and between 1.5 and 4x for 1,3-D isomers for the concentration range of 0.6 to 60 mg kg(-1), depending on temperature. For the same initial concentration range, the variation in the half-order rate constants was between 1.4 and 1.7x for MITC and between 3.1 and 6.1x for 1,3-D isomers, depending on temperature. Second-order kinetics and the Michaelis-Menten model did not satisfactorily describe the degradation at all initial concentrations. The degradation of MITC and 1,3-D was primarily biodegradation, which was affected by temperature between 20 and 40 degrees C, following the Arrhenius equation (r2 > 0.74).     

Adsorption of Cu(II) ions from aqueous solutions on biochars prepared from agricultural by-products

In this study, the adsorption of Cu(II) from aqueous solutions by agricultural by-products, such as rice husks, olive pomace and orange waste, as well as compost, was evaluated. The aim was to obtain sorbent materials (biochars) through hydrothermal treatment (300?°C) and pyrolysis (300?°C and 600?°C). The effect of adsorbent dose, pH, contact time and initial Cu(II) concentration in batch-mode experiments was investigated. The optimum Cu(II) adsorption conditions was found to occur at 5-12?g/L adsorbent dose, initial pH 5-6, and reaction time 2-4?h. Furthermore, the adsorption kinetics were best described by the pseudo-second order model for all the tested materials, while the adsorption equilibrium best fitted by the linear and Freundlich isotherms. Comparing rice husks and olive pomace, the higher adsorption capacity resulted after pyrolysis at 300?°C. With respect to the orange waste and compost, the highest adsorption capacity was observed using biochars obtained after hydrothermal treatment and pyrolysis at 300?°C.     

Heterogeneous photocatalysed degradation of a herbicide derivative, isoproturon in aqueous suspension of titanium dioxide

Heterogeneous photocatalysed degradation of a herbicide derivative, N-(4-isopropylphenyl)-N',N'-dimethylurea (Isoproturon, 1) was investigated in aqueous suspensions of titanium dioxide by monitoring the change in absorption intensity and depletion in Total Organic Carbon content as a function of irradiation time. The degradation kinetics was studied under different conditions such as pH, catalyst concentration, substrate concentration, different types of TiO(2) and in the presence of electron acceptors such as hydrogen peroxide (H(2)O(2)), potassium bromate (KBrO(3)) and potassium persulphate (K(2)S(2)O(8)) besides molecular oxygen. The degradation rates were found to be strongly influenced by all the above parameters. The photocatalyst Degussa P25 was found to be more efficient as compared with other photocatalysts. An attempt was made to identify the degradation product through GC-MS analysis technique.     

4株苯磺隆降解菌的分离鉴定及其生长特性

从长期受农药苯磺隆污染的土壤中通过采用富集培养分离技术得到4株以苯磺隆为唯一碳源生长的细菌,分别将其命名为B1、B2、B3和B4。通过观察这4种菌株的形态学特征,研究其生理生化特性以及分析其16S rDNA序列,初步鉴定菌株B1为铜绿假单胞菌（Pseudomonas aeruginosa）,B2为戴尔福特菌（Delftia sp.）,B3为微杆菌（Microbacterium sp.）,B4为产碱杆菌（Alcaligenes sp.）。并通过研究温度、初始pH值、接种量、苯磺隆初始浓度、培养基体积、氮源、碳源、Mg^2＋浓度等因素对4种菌株生长情况的影响,确定了菌株的最佳生长条件。结果显示,B1菌株的最适温度为35℃,其他3株菌株均为30℃。菌株B3最适pH为8.0,其余3株菌株均为pH7.0。B1和B3菌株最适接种量为15%,B2和B4最适接种量为10%。菌株B3最适苯磺隆初始浓度为100mg·L^-1,其余菌株最适苯磺隆初始浓度均为200mg·L^-1。4株菌株最适培养基体积均为75mL,最适氮源均为硝酸铵,最适碳源均为葡萄糖。B2菌株最适Mg^2＋浓度为100mg·L^-1,其余3株菌株均为200mg·L^-1。B1和B4菌株最适NaCl浓度为20g·L^-1,B2菌株NaCl浓度为5-30g·L^-1,B3菌株最适NaCl浓度为50g·L^-1。该结果为利用微生物对农药苯磺隆污染的土壤进行原位生物修复提供理论依据。