铁碳微电解处理制药废水的初探

采用铁碳微电解法预处理制药废水,研究影响微电解预处理废水的各种因素.实验探讨了铁碳比、pH值及反应时间对废水COD(化学需氧量)去除率的影响,以确定最佳工艺条件.研究结果表明:微电解法处理制药废水时,当原水的pH值为4,Fe/C比为2∶1,反应时间80min,COD去除率为68.0％.     

铁碳微电解法处理霜脲氰废水的实验研究

为了解决霜脲氰农药废水难以直接生化降解的难题,采用铁碳微电解法对霜脲氰农药废水进行预处理,实验结果表明,废水初始pH值、铁碳比、铁碳填料投加量和反应时间对实验结果均产生直接影响.霜脲氰废水的最佳处理条件为:pH值为2,铁碳比为3∶1,投加量为1L废水280 g,反应时间80 min.COD去除率为47.95％,CN-去除率为39.75％,ρ(B)/ρ(C)达到0.20 ～ 0.25间,大大提高了霜脲氰废水的可生化性,表明铁碳微电解法可作为霜脲氰废水的预处理方法,为霜脲氰废水的预处理工艺提供新思路.     

铁碳微电解工艺预处理制药废水实验研究

制药废水中含有大量难生物降解的化学物质,其BOD5/COD值很低,可生化性差。故一般仅采用生化处理很难将其COD降低到排放标准,现采用铁碳微电解法并串联Fenton工艺对某制药厂废水进行预处理。以废水COD为指标并通过正交试验确定达到最佳处理效果的各因素的最佳组合条件为:前端的铁碳微电解反应时间为2.5 h,pH值为5,铁碳质量比1:2,Fe粉的投加量为120 g/L;后续Fenton反应投加30%H2O23 mL/L,FeSO.47H2O(100 g/L)400 mg/L,调节pH值为2,反应时间2.5 h,总去除率大于70%,为工业化应用做出铺垫。     

甲苯硝化废水的微电解-Fenton氧化预处理

采用铁碳微电解-Fenton氧化联合工艺处理甲苯硝化废水,探讨了溶液pH值、铁炭投加量、铁炭比例、H2O2投加量和反应时间等因素对微电解-Fenton氧化处理硝化废水的影响规律,获得微电解-Fenton氧化处理硝化废水的最佳工艺条件:废水pH在3左右,铁炭投加量为0.6 g/L,Fe/C质量比为4∶1,反应时间为1.5h,微电解后H2O2投加量为20 ml/L,反应时间为1 h。硝化废水经微电解-Fenton氧化处理后,COD由29 146mg/L降至6 477 mg/L,COD去除率达77.8%,BOD5/COD由0提高到0.37左右,废水可生化性显著增强。     

铁炭微电解预处理聚酯树脂废水的试验研究

采用铁炭微电解法预处理聚酯树脂废水研究,先进行正交试验,考察铁屑投加量、铁炭比和废水初始pH值对微电解效果的影响,接着在正交试验的基础上进行单因素试验,确定铁炭微电解法的最优工艺参数。试验结果表明:废水初始pH值对微电解处理聚酯树脂废水的影响最大,其次是铁屑投加量和铁炭比,最适工艺条件为:室温,废水初始pH值为2.0,铁屑投加量为100 g/L,铁炭质量比为1:1,曝气搅拌反应时间2.0 h。在此工艺条件下,BOD5/CODcr从0.17增加到0.33;此外,废水的CODcr去除率也可达到50.91%,这大大降低了后续生化处理的有机负荷。     

电Fenton法处理染料废水的研究

采用电Fenton法预处理染料废水,对影响COD及色度去除率的各种因素,包括内电解反应的初始pH值、铁的投加量、铁炭投加比,Fenton试剂氧化处理过程中初始pH值、H2O2的投加量及投加方式、反应时间等进行了研究。结果表明,内电解反应的最佳条件为：pH值为3.0,铁的投加量为25g/L,Fe/C为1：1.3;Fenton试剂氧化处理染料废水的最佳条件为：H2O2投加量为30mmol/L,pH值为内电解出水pH值（pH值为4.0左右）,反应时间为50min。COD去除率可达58%,色度去除率可达95%以上。     

铁碳微电解法预处理聚氯乙烯(PVC)离心母液废水

采用铁碳微电解法对聚氯乙烯(PVC)离心母液废水进行预处理。分别考察反应时间、铁粉投加量、Fe/C(质量比)、pH值及曝气速率对母液废水中的COD和聚乙烯醇(PVA)去除率的影响,并在此基础上通过正交实验确定了废水COD的最佳处理条件。结果表明,最佳处理条件为:反应时间为4 h、铁粉投加量为30 g/L、Fe/C为1:2、pH值为2、曝气速率为0.8 L/min。在该条件下,废水中COD、PVA和TOC的平均去除率分别为(67%±2)%、(98%±1)%和(55%±3)%,废水的BOD/COD值从0.3提高到0.5,可生化性得到了显著提高。同时,废水中的NH3-N、浊度也在很大程度上得到了去除,出水中总铁含量也很低。     

微电解-Fenton联合工艺处理酸化压裂废水

采用微电解-Fenton氧化法对酸化压裂模拟废水进行处理,有效地降低了废水的COD,试验中考察了微电解反应进水pH值、铁碳质量比、反应时间以及联合Fenton工艺中废水的pH值、H2O2加入量、反应时间对COD去除率的影响。结果表明,微电解法工艺的优化条件:pH2.5左右,反应停留时间120min,铁碳质量比5∶1;Fenton反应的优化条件:微电解出水调pH4.0左右,反应时间75min,H2O(2质量分数为10%)加入量7.5ml/L,最终处理的出水COD去除率达64.8%,联合工艺的COD去除率比单一的微电解法提高了26.3%,为后续的处理创造了有利的条件。     

含铜黄连素废水的铁碳微电解预处理及铜回收研究

利用铁碳微电解技术对含铜黄连素制药废水进行预处理,通过单因素试验确定了反应时间,铁粉和废碳投加量,pH等因素对处理效果的影响,并设计了回收金属铜的工艺流程.结果表明:采用铁碳微电解工艺处理初始Cu2+浓度约为20000mg/L,黄连素浓度为1 700～1 900mg/L的含铜黄连素制药废水,当废水pH为2.0～3.0,...     

铁碳微电解法处理印染助剂废水的试验研究

采用铁碳微电解法对印染助剂废水进行试验处理,研究不同pH、铁碳填料与废水填充比、反应时间对该废水CODcr去除率的影响,寻求最佳反应参数。试验表明:采用铁碳微电解法,对印染助剂废水具有良好的降解效果,出水COD平均去除率可达到73.15%。反应最佳条件为pH=3.0,铁碳微电解填料填充比为1.5:1,反应时间为1 h。     

Distribution and ecological effect of mercury in Laogang landfill, Shanghai, China

Laogang landfill near Shanghai is the largest landfill in China, and receives about 10000 t of daily garbage per day, Samples of topsoil and plants were analyzed to evaluate mercury pollution from the landfill. For topsoil samples, there were significant correlations among total mercury （HgT）, combinative mercury （Hgc） and gaseous mercury （HgG）, and content of total organic carbon （TOC）, but, no significantly relationship was found between Hg content and filling time. Hg content changes in vertical profiles with time showed that the average Hgv of profiles 1992, 1996, and 2000 was similar, but their average HgG was quite different. HgT was significantly correlated with Hgc in profile 1992 and 2000, and Hgv was significantly correlated with Hg6 in profile 1996. HgG/Hgv ratio in profile samples decreased in the order of （HgG,/HgT）1992〉（HgG/HgT）1996〉〉（HgG/HgT）2000. A simple outline of Hg release in landfill could be drawn： with increasing of filling time, degradation undergoes different biodegradation, accordingly, gaseous mercury goes through small, more, and small proportion to total mercury. Distribution of Hg in plants was inhomogeneous, following the order of leaf〉root〉stem. The highest value of leaf may be associated with higher atmospheric Hg from landfill. Ligneous plants （e.g. Phyllostachys glanca, Prunus salicina and Ligustrum lucidum） are capable of enriching more Hg than herbaceous plants.     

EDTA-enhanced phytoremediation of lead contaminated soil by Bidens maximowicziana

Phytoremediation is a potential cleanup technology for the removal of heavy metals from contaminated soils.Bidens maximowicziana is a new Pb hyperaccumulator,which not only has remarkable tolerance to Pb but also extraordinary accumulation capacity for Pb.The maximum Pb concentration was 1509.3 mg/kg in roots and 2164.7 mg/kg in overground tissues.The Pb distribution order in the B. maximowicziana was:leaf>stem>root.The effect of amendments on phytoremediation was also studied.The mobility of soil Pb and the Pb concentrations in plants were both increased by EDTA application.Compared with CK(control check),EDTA application promoted translocation of Pb to overground parts of the plant.The Pb concentrations in overground parts of plants was increased from 24.23-680.56 mg/kg to 29.07-1905.57 mg/kg.This research demonstrated that B.maximowicziana appeared to be suitable for phytoremediation of Pb contaminated soil,especially,combination with EDTA.     

Decomposition of alachlor by ozonation and its mechanism

Decomposition and corresponding mechanism of alachlor, an endocrine disruptor in water by ozonation were investigated. Results showed that alachlor could not be completely mineralized by ozone alone. Many intermediates and final products were formed during the process, including aromatic compounds, aliphatic carboxylic acids, and inorganic ions. In evoluting these products, some of them with weak polarity were qualitatively identified by GC-MS. The information of inorganic ions suggested that the dechlorination was the first and the fastest step in the ozonation of alachlor.     

Enzymatic oxidation of aqueous pentachlorophenol

The influence of the nonionic surfactant Tween 80 on pentachlorophenol （PCP） oxidation catalyzed by horseradish peroxidase was studied. The surfactant was tested at concentrations below and above its critical micelle concentration （CMC）. Enhancement of PCP removal was observed at sub-CMCs. The presence of Tween 80 in the reaction mixture reduced enzyme inactivation which occurred through a combination of free radical attack and sorption by precipitated products. A simple first-order model was able to simulate time profiles for enzyme inactivation in the presence or absence of Tween 80. At supra-CMCs, the surfactant caused noticeable reductions in PCP removal, presumably through micelle partitioning of PCP which precluded the hydrophobic PCP molecule from interacting with the enzyme.     

基于综合水质标识指数和对应分析法的校园河道水质评价

以三峡大学的校园河道求索溪为研究对象,利用综合水质标识指数法确定求索溪水质类别,分析其水质时空变化规律,并利用对应分析法得出求索溪中不同监测点的主要污染因子.研究结果表明:求索溪整体的综合水质标识指数为7.423,整体水质为劣V类(地表水环境质量标准GB 3838-2002)且黑臭.从时间变化来看,求索溪4月份的水质最差,5月份次之,4、5月份所有监测点的水质都劣于V类且黑臭;8月份水质最好,水质为Ⅳ类;从空间分布来看,8个监测点综合水质标识指数均超过6.0,水质为劣V类,其中6号监测点的水质相对最好,监测点3号的水质相对最差;对应分析法得出求索溪的整体水体污染程度受总氮因子的影响最大,其次为总磷.该研究拟为求索溪及类似校园河道的水环境治理研究提供基础依据和参考.     

Effects of chitosan on growth of an aquatic plant (Hydrilla verticillata) in polluted waters with different chemical oxygen demands

Effects of chitosan on a submersed plant, Hydrilla verticillata, were investigated. Results indicated that H. venicillata could prevent ultrastructure phytotoxicities and oxidativereaction from polluted water with high chemical oxygen demand (COD). Superoxide dismutase (SOD) activity and malondialdehyde (MDA) contents in H. verticillata treated with 0.1% chitosan in wastewater increased with high COD (980 mg/L) and decreased with low COD (63 mg/L), respectively. Ultrastructural analysis showed that the stroma and grana of chloroplast basically remained normal. However, plant cells from the control experiment (untreated with chitosan) were vacuolated and the cell interval increased. The relict of protoplast moved to the center, with cells tending to disjoint. Our findings indicate that wastewater with high COD concentration can cause a substantial damage to submersed plant, nevertheless, chitosan probably could alleviate the membrane lipid peroxidization and ultrastructure phytotoxicities, and protect plant cells from stress of high COD concentration polluted water.     

Removal of cadmium using MnO2 loaded D301 resin

MnO2 loaded weak basic anion exchange resin D301 （Anion exchange resin, macroreticular weak basic styrene） as adsorbent has been prepared and applied to the removal of cadmium. The adsorption characteristics have been investigated with respect to effect of pH, equilibrium isotherms, removal kinetic data, and interference of the coexisting ions. The results indicated that the Cd^2＋ could be efficiently removed using MnO2 loaded D301 resin in the pH range of 3-8 from aqueous solutions with the co-existence of high concentration of alkali and alkaline-earth metals ions. The saturate adsorption capacity of the Cd^2＋ was 77.88 mg/g. The adsorption process followed the pseudo first-order kinetics. The equilibrium data obtained in this study accorded excellently with the Langmuir adsorption isotherm.     

Effect of coagulation pretreatment on the fouling of ultrafiltration membrane

The purpose of this study is to understand the effect and mechanism of preventing membrane fouling, by coagulation pretreatment, in terms of fractional component and molecular weight of natural organic matter （NOM）. A relatively higher molecular weight （MW） of hydrophobic compounds was responsible for a rapid decline in the ultrafiltration flux. Coagulation could effectively remove the hydrophobic organics, resulting in the increase of flux. It was found that a lower MW of neutral hydrophilic compounds, which could remove inadequately by coagulation, was responsible for the slow declining flux. The fluxes in the filtration of coagulated water and supernatant water were compared and the results showed that a lower MW of neutral hydrophilic compounds remained in the supernatant water after coagulation could be rejected by a membrane, resulting in fouling. It was also found that the coagulated flocs could absorb neutral hydrophilic compounds effectively. Therefore, with the coagulated flocs formed on the membrane surface, the flux decline could be improved.     

Penetration analysis of elements and bioleaching treatment of spent refractory for recycling

Acidithiobacillus ferrooxidans ATCC23270 and Acidithiobacillus thiooxidans TM-32 were used for bioleaching of spent refractories of aluminium and copper melting furnaces for their recycling.Firstly,penetration of elements into aluminium melting furnace refractory was investigated and it was found that up to 7 cm from surface was contaminated.Comparison on leaching efficiency by the strains ATCC23270 and TM-32 found that the strain ATCC23270 could treat larger amount of the refractories than the strain TM-32 could do.In the experiment of bioleaching of spent refractory aluminium melting furnace by the strain ATCC23270,high leaching efficiency were obtained on Al,Si,and Ca,and extremely low leaching performance was,however,shown on the rest of elements i.e.,Na,Mn,and Zn.Under the strain TM-32 use,relatively high leaching performance was recognized on Al,Si,Ca,Na,Mn,and Zn.In the experiment of bioleaching for spent refractory copper melting furnace,almost the same leaching trends were shown on Cu,Zn,Al,and Si under the strains ACTT23270 and TM-32 uses.     

Simultaneous removal of ammonium and phosphate by zeolite synthesized from coal fly ash as influenced by acid treatment

Zeolite synthesized from fly ash （ZFA） without modification is not efficient for the purification of NH4＋ and phosphate at low concentrations that occur in real effluents, despite the high potential removal capacity. To develop an effective technique to enhance the removal efficiency of ammonium and phosphate at low concentrations, ZFA was modified with acid treatment and the simultaneous removal of ammonium and phosphate in a wide range of concentration was investigated. It was seen that when compared with untreated ZFA, only the treatment by 0.01 mol/L of H2SO4 significantly improved the removal efficiency of ammonium at low initial concentrations. The behavior was well explained by the pH effect. Treatment by more concentrated H2SO4 led to the deterioration of the ZFA structure and a decrease in the cation exchange capacity. Treatment by 0.01 mol/L H2SO4 improved the removal efficiency of phosphate by ZFA at all initial P concentrations, while the treatment by concentrated H2SO4 （≥0.9 mol/L） resulted in a limited maximum phosphate immobilization capacity （PIC）. It was concluded that through a previous mild acid treatment （e.g. 0.01 mol/L of H2SO4）, ZFA can be used in the simultaneous removal of NH4＋ and P at low concentrations simulating real effluent.