阴极原位产H2O2强化光电催化降解水中EDTA的研究

本研究构建了以活性碳纤维(Activated Carbon Fiber,ACF)为阴极,TiO_2/Ti与Ru O_2/Ti为双阳极的光电催化体系.该体系中,Ru O_2/Ti电阳极和TiO_2/Ti光阳极均有氧化作用,可同时氧化降解污染物;且电阳极具有较强析氧作用,能产生大量O_2;ACF阴极具有还原作用,可将体系中产生的O_2原位还原为H_2O_2;H_2O_2在紫外光下产生·OH,进而强化光电催化与电催化氧化过程,实现对水中乙二胺四乙酸二钠(EDTA)的高效去除.本论文详细考察了电流密度、pH、曝气等因素对EDTA降解效果的影响.结果表明,在EDTA初始浓度为300 mg·L~(-1)、溶液初始pH=4.84、电流密度为12 m A·cm~(-2)和光电流密度为0.012 m A·cm~(-2)的条件下,反应90 min后,EDTA降解率高于90%.该催化体系实现了EDTA的高效降解.     

高级氧化法氧化含邻硝基甲苯废水过程的动力学

研究了水溶液中邻硝基甲苯在有O3或O3／H2O2情况下的氧化反应过程，并建立了动力学模型。在293K、pH值3－10条件下对反应进行测定。实验结果表明，臭氧衰减速率对于O3来说反应级数为1，而对于邻硝基甲苯来说则随pH值变化和H2O3的有无而变化，实验结果与理论预测相吻合。     

O3/H2O2氧化工艺去除水中硝基苯的研究

以硝基苯为代表性有机污染物 ,对比了臭氧化和O3/H2 O2 高级氧化工艺对水中硝基苯的去除效果 .发现与臭氧化相比 ,O3/H2 O2 高级氧化工艺可以显著地提高水中硝基苯的去除效率 .无论在臭氧化还是在O3/H2 O2 高级氧化工艺中 ,水中硝基苯的降解都主要是由OH·完成的 .通过考察O3/H2 O2 高级氧化工艺去除水中硝基苯的影响因素发现 ,在O3和过H2 O2 投量相同的条件下 ,多次投加O3和催化剂H2 O2 对水中硝基苯的处理效果明显优于一次性投加 ;在本次试验条件下 ,O3/H2 O2 高级氧化工艺降解蒸馏水和自来水中硝基苯的最优H2 O2 与O3摩尔比均为 0 5 ,HCO- 3碱度水平 (以CaCO3计 )在低于 1 0 0mg/L范围内对去除硝基苯无显著影响     

γ辐照和H2O2联合作用下五氯酚(PCP)的降解

研究了水溶液中的五氯酚(PCP)在γ辐照和过氧化氢(H2O2)联合作用下的降解.PCP的初始浓度为27.7 mg·L-1,外加H2O2的初始浓度为0、50和100 mg·L-1.结果表明,PCP在不同条件下的辐照降解符合准一级动力学方程.当外加H2O2的初始浓度在0～100 mg·L-1时,PCP的去除率、矿化率和脱氯...     

粉煤灰增强超声/H2O2降解左氧氟沙星的实验研究

研究粉煤灰对超声/H2O2体系降解左氧氟沙星的增强效果,考察了粉煤灰添加量、H2O2浓度、溶液初始pH值、左氧氟沙星初始浓度等对降解效果的影响.结果表明,与单独超声,H2O2氧化,超声/H2O2,超声/粉煤灰,粉煤灰/H2O2氧化相比,粉煤灰有效增强了超声/H2O2体系对左氧氟沙星的降解,降解反应符合一级反应动力学.粉煤灰添加量为1.5g/L,H2O2浓度为15.0mmol/L,pH=7.16,超声功率325W,左氧氟沙星初始浓度20mg/L,反应160min,左氧氟沙星的去除率达到99.12%,TOC去除率为17.37 %.利用荧光探针法对不同体系产生的·OH浓度进行了分析比较,粉煤灰作为非均相催化剂,主要在于发生类Fenton反应.采用HPLC/MS/MS方法对3种反应产物进行了分析,结果表明左氧氟沙星主要是通过喹诺酮环失去-C2,哌嗪环去亚甲基化以及·OH进攻喹诺酮环发生降解.     

Flow and geochemical modeling of drainage from Tomitaka mine, Miyazaki, Japan

The chemistry and flow of water in the abandoned Tomitaka mine of Miyazaki, western Japan were investigated. This mine is located in a non-ferrous metal deposit and acid mine drainage issues from it. The study was undertaken to estimate the quantities of mine drainage that needs to be treated in order to avoid acidification of local rivers, taking into account seasonal variations in rainfall. Numerical models aimed to reproduce observed water levels and fluxes and chemical variations of groundwater and mine drainage. Rock–water interactions that may explain the observed variations in water chemistry are proposed. The results show that: (1) rain water infiltrates into the deeper bedrock through a highly permeable zone formed largely by stopes that are partially filled with spoil from excavations (ore minerals and host rocks); (2) the water becomes acidic (pH from 3 to 4) as dissolved oxygen oxidizes pyrite; (3) along the flow path through the rocks, the redox potential of the water becomes reducing, such that pyrite becomes stable and pH of the mine drainage becomes neutral; and (4) upon leaving the mine, the drainage becomes acidic again due to oxidation of pyrite in the rocks. The present numerical model with considering of the geochemical characteristics can simulate the main variations in groundwater flow and water levels in and around the Tomitaka mine, and apply to the future treatment of the mine drainage.     

性畸变疣荔枝螺体内保护酶系统活力的研究

以疣荔枝螺（Thais clavigera）为研究材料,取不同程度性畸变雌性个体,以生存于同一生境中的雄性个体为对照,检测了性畸变个体与正常雌性和雄性超氧化物歧化酶（SOD）、脂质过氧化物（LPO）及过氧化氢酶（CAT）活性的差异,探讨TBT对性畸变个体SOD、LPO及CAT活性的影响。结果表明,疣荔枝螺性畸变程度愈严重,以上生化指标的差异愈明显,并呈现一定的规律性。     

CaO2不同投加方式对底泥磷释放的抑制效果分析

利用CaO₂进行底泥修复,在实验室模拟条件下,研究了2种不同的CaO₂投加方式(混匀和覆盖)上覆水活性磷酸盐(SRP)的变化趋势,并通过底泥磷形态之间的转变来分析其不同效果的原因.结果表明,混匀条件和覆盖条件下上覆水的SRP浓度呈现2种不同的变化趋势,前者先降低后增加而后者则持续降低,平均释放速率分别为6.077 mg/(m²·d)和-0.879mg/(m²·d).底泥磷的分级提取实验结果表明,铁磷的不同变化趋势是CaO₂投加方式引起底泥磷释放不同效果的内在原因.     

Degradation kinetics and mechanism of trace nitrobenzene by granular activated carbon enhanced microwave/hydrogen peroxide system

The kinetics of the degradation of trace nitrobenzene (NB) by a granular activated carbon (GAC) enhanced microwave (MW)/hydrogen peroxide (H₂O₂) system was studied. Effects of pH, NB initial concentration and tert-butyl alcohol on the removal efficiency were examined. It was found that the reaction rate fits well to first-order reaction kinetics in the MW/GAC/H₂O₂ process. Moreover, GAC greatly enhanced the degradation rate of NB in water. Under a given condition (MW power 300 W, H₂O₂ dosage 10 mg/L, pH 6.85 and temperature (60±5)℃), the degradation rate of NB was 0.05214 min^-1 when 4 g/L GAC was added. In general, alkaline pH was better for NB degradation; however, the optimum pH was 8.0 in the tested pH value range of 4.0-12.0. At H₂O₂ dosage of 10 mg/L and GAC dosage of 4 g/L, the removal of NB was decreased with increasing initial concentrations of NB, indicating that a low initial concentration was beneficial for the degradation of NB. These results indicated that the MW/GAC/H₂O₂ process was effective for trace NB degradation in water. Gas chromatography-mass spectrometry analysis indicated that a hydroxyl radical addition reaction and dehydrogenation reaction enhanced NB degradation.     

卵圆卡盾藻香港株过氧化氢产生的影响因素研究

研究了卵圆卡盾藻香港株(Chattonella ovata,Hong Kong strain,COHK)在不同生长期、盐度和营养盐条件下的生长及过氧化氢(H2O2)的产生特点.结果表明,过氧化氢浓度峰值出现在COHK对数生长期(4～8 d),以第6 d达到最大,为2.91×10-4nmol.cell-1.在N∶P为16∶1、32∶1和64∶1的情况下,COHK生长较快,以32∶1时生长速率最快(0.58 div.d-1).COHK产生H2O2的量与藻类生长呈相反趋势,在N∶P为4∶1和8∶1的情况下,藻细胞生长率较低,但单位藻细胞H2O2浓度较高.单位藻细胞H2O2浓度在N∶P为4∶1时最大,达到1.26×10-4nmol.cell-1.COHK在盐度为20和25时生长率较高,在盐度为10、15和30时生长率较低,表明低盐和高盐条件均不利于COHK的生长.低盐度和高盐度均有利于COHK过氧化氢的产生,在盐度为10时,单位藻细胞的H2O2量最高,达到2.2×10-4nmol.cell-1;但盐度在15～25范围内,单位藻细胞H2O2量相差不大(0.7×10-4～0.9×10-4nmol.cell-1).Fe3+可显著影响COHK的生长,Fe3+浓度范围为0.2×10-8～1×10-8mol.L-1时,COHK生长率较高.缺铁条件下(Fe3+浓度为0),COHK生长率最低(0.1 div.d-1),而Fe3+浓度较高时(5×10-8mol.L-1),藻细胞生长率也有所降低.缺铁以及高铁条件下,卵圆卡盾藻的H2O2产量增加,H2O2浓度分别为0.97×10-4和0.95×10-4nmol.cell-1.