SBR活性污泥吸附水中重金属离子的研究

研究了SBR活性污泥对重金属离子(Cu2+、Zn2+、Mn2+、Fe3+)的吸附作用。结果表明:在30℃温度下,pH为5时,其对Cu2+、Zn2+、Mn2+的去除率达到最大值50%左右;当pH为3时,对Fe3+的去除率达到最大值73.6%。吸附动力学过程可用二级吸附速率方程描述。在10~30℃温度范围内,随着温度的升高,Cu2+、Zn2+、Mn2+、Fe3+的去除率分别由54.6%、46.3%、45.3%6、8.9%,增大到58.6%、51.3%、49.6%、73.6%。当重金属离子初始质量浓度为50 mg/L,污泥投加量为0.2 g时,Cu2+、Zn2+、Mn2+和Fe3+的去除率达到最大值,分别为61.5%、54.3%、53.3%和76.2%。吸附等温线结果表明,Cu2+、Zn2+、Mn2+、Fe3+在吸附剂上的吸附可用Freundlich方程描述。     

国家自然科学基金青年科学基金项目 核壳结构Fe_3O_4/P(S-MA)纳米材料的可控制备与脱除重金属离子的机制

<正>(项目批准号:51303074)为了解决工业废水中低浓度的Cu2+,Zn2+,Hg2+,Cd2+,Cr3+和Ni2+等重金属离子能够快速聚集、分离与脱除的目的,本项目提出了以含羟基、羧基、氨基、巯基和硫醚基等官能团的核壳结构的Fe3O4/P(S-MA)纳米材料作为重金属离子络合剂,研究该材料对重金属离子的脱除机制和选择性,对于     

典型微量金属元素对铜绿微囊藻生长影响的研究

针对Cu、Fe、Zn的不同离子浓度对铜绿微囊藻生长的影响进行研究,以期为水体富营养化防治的进一步开展提供理论支持。试验采用BG11培养基,分别测定了3种微量金属在不同浓度下铜绿微囊藻细胞密度和细胞叶绿素a含量变化。结果表明:当Cu、Fe、Zn浓度分别为0.001、3~12、0.05 mg/L时,铜绿微囊藻生长最佳,且在最佳浓度范围内铜绿微囊藻对Cu、Fe、Zn的利用率与其生长状况呈明显的相关性。Cu、Fe、Zn在不同浓度范围对藻类光合作用的促进或抑制是影响其生长的主要因素。因此,控制水体蓝藻暴发时,除了调节氮磷以外,通过微量金属元素浓度的调节也可作为一条有效抑制蓝藻暴发的途径。     

城市地表径流胶体对重金属下渗迁移行为的影响

为了解城市地表径流胶体对重金属在下渗设施中迁移行为的影响,提取道路雨水径流中的胶体,采用下渗柱试验研究了存在径流胶体时Cu~(2+)、Pb~(2+)和Cd~(2+)的下渗迁移出流质量浓度变化,分析进水流速、pH值、Na~+浓度、重金属离子共存和胶体粒径对胶体携带重金属迁移行为的影响。结果表明:径流胶体能够促进重金属离子的下渗迁移;进水流速越高,径流胶体对重金属离子的携带迁移作用越明显;弱酸性条件更有利于径流胶体对重金属离子的携带迁移;雨水径流中存在Na~+或多种重金属离子共存时,胶体携带重金属离子的下渗迁移过程会受到抑制,且离子浓度越大,其受抑制作用越明显;胶体粒径会显著影响径流胶体对重金属离子的携带迁移能力,胶体粒径越小,越容易携带重金属离子下渗迁移。     

解偶联剂对缺氧污泥产率系数的影响

利用缺氧SBR反应器,研究解偶联剂2,4,5-三氯酚(TCP)对缺氧污泥产率系数的影响.类似于好氧污泥的研究结果,解偶联剂也能降低缺氧污泥的污泥产率系数.当TCP从0增加到10mg/L时,真实产率YH降低了30%,而表观产率Yobs却降低了54%,说明表观产率Yobs受解偶联剂的影响更加显著.     

Cu2+长期胁迫下两级AO工艺运行效能及污泥特性研究

以深圳市某水质净化厂活性污泥重金属Cu中毒事件为背景,建立实验室小试模拟系统,考察了不同梯度Cu²⁺长期胁迫下两级AO工艺的运行效能及污泥特性。结果表明,进水中加入1 mg/L Cu²⁺,系统运行效能保持稳定;当Cu²⁺浓度提高到5 mg/L和25 mg/L时,短期内活性污泥系统运行效能显著下降,但随着适应外界环境,3 d后系统效能逐步恢复;然而当活性污泥中重金属Cu含量累积达94.3 mg/gVSS,系统运行效能大幅下降,面临系统崩溃;解除Cu²⁺长期胁迫,系统运行效能逐步恢复。比硝化耗氧速率(SOUR_A)呈现与系统运行效能相似的变化规律,随着进水Cu²⁺浓度的提高,SOUR_A逐渐下降。当SOUR_A抑制率超过40%时,系统存在恶化可能。随着进水Cu²⁺浓度提高和胁迫时间延长,活性污泥胞外聚合物(EPS)含量先增大后减少,且组分C1和C4为抵抗Cu²⁺胁迫压力扮演重要作...     

浸提时间对城市污泥重金属浸出特性的影响

在研究含工业废水污泥中Zn、Cu、Pb、Cr、Mn、Ni含量的基础上,应用固体废物浸出毒性方法,以不同浸出时间对污泥中重金属的浸出特性进行了实验研究.结果表明:污泥中Mn和Zn含量较高,其次为Cu和Ni,而毒性较大的Pb和Cr含量较低.浸提时间对污泥中重金属的浸出具有重要影响,污泥中的Zn、Cu、Ni最大浸出浓度在8h时,而Fe和Mn随着浸提时间增加而增加;浸提时间对污泥中重金属浸出量的影响因该重金属的化学性质不同而存在较明显的差别,这可能与浸提过程中的吸附-解吸过程、络合-解离过程和溶解-沉淀/共沉淀等因素有关.     

Pb2+、Cu2+在黄颡鱼性腺中的富集及其对性腺发育的胁迫

研究Pb2+、Cu2+在其不同质量浓度(0.10 mg/L、0.25 mg/L、0.50 mg/L)情况下在黄颡鱼性腺中的富集特性以及对性腺发育的影响。结果表明,黄颡鱼性腺(卵巢)对Pb2+、Cu2+有较强的富集能力,在暴露期间的20—30 d内,Pb2+、Cu2+在性腺内的富集量分别与时间呈线性关系,之后呈对数关系。其中,Cu2+的富集显著大于Pb2+(P<0.01);性腺中的重金属富集与水溶液中Pb2+、Cu2+的浓度相关(P<0.01),具有明显的时间效应和剂量效应。黄颡鱼性腺细胞的发育水平,亦与溶液Pb2+、Cu2+的浓度与暴露时间相关。     

H2O2/O3协同灭活水中隐孢子虫影响因素研究

开展了H2O2/O3灭活隐孢子虫(Cryptosporidium parvum)的研究。考察了H2O2和O3投加比例、过氧化氢作用效果、无机金属离子等因素的影响。结果表明,H2O2/O3协同技术具有最佳的灭活效果,H2O2的投加不仅降低了药剂(O3)的初始浓度(投量2.0mg/L),而且缩短了灭活时间(7.0 min),达到理想的灭活效果(灭活率99.0%以上)时,H2O2/O3摩尔比为0.8;同时考察了水中常见离子对H2O2/O3灭活效果的影响,低浓度的Ca2+,Mg2+和Cu2+等二价金属离子均对灭活起到一定促进作用,一价离子Na+对灭活无明显的作用,而NO-3,HCO-3和Cl-在一定范围内抑制了H2O2/O3对隐孢子虫的灭活。     

加载絮凝—污泥回流工艺处理 重金属废水的研究

电子行业废水的重金属处理通常采用混凝沉淀方法。然而,常规混凝方法存在药剂投加量大、污泥产量多、水质波动影响大等不足。因而,本文提出了加载絮凝—污泥回流工艺,在小试、中试基础上,对原处理工程进行了改造。改造后出水重金属含量稳定。Cu2+、TCr和Ni2+的含量上限值分别小于0.5 mg/L、0.6 mg/L和0.5 mg/L,与改造前相比,改造后PAC和PAM用量可分别节省70%和93%,污泥产生量也会相应减少。加载絮凝—污泥回流工艺可实现电子行业废水重金属达标排放,同时可降低处理成本和污泥产量,具有较好的应用前景。     

Evaluation of heavy metal inhibition of activated sludge by TTC and INT-electron transport system activity tests.

TTC and INT-electron transport system activity tests were compared for assessing heavy metal inhibition of activated sludge. The median inhibitory concentrations (IC50s) of Cu2+, Zn2+, Cd2+, Hg2+, Ni2+, Pb2+ and Ag+ measured via TTC test were lower than those measured via INT test, which indicates that the INT-electron transport system activity test was less sensitive to heavy metal toxicity than the TTC test. Tested heavy metals brought about similar decrease in TTC-electron transport system activity and COD removal rate, but less decrease in INT-electron transport system activity than COD removal rate, which suggests that the TTC-electron transport system activity is a better parameter for reflecting heavy metal inhibition of activated sludge than INT-electron transport system activity. The ranking of tested heavy metals in order of decreasing toxicity based on TTC test was Hg2+, Cd2+, Cu2+, Ag+, Zn2+, Ni2+ and Pb2+, and the ranking based on INT test was Hg2+, Ag+, Cu2+, Cd2+, Zn2+, Ni2+ and Pb2+.     

Biological treatment of heavy metals in acid mine drainage using sulfate reducing bioreactors.

The uncontrolled release of acid mine drainage (AMD) from abandoned mines and tailing piles threatens water resources in many sites worldwide. AMD introduces elevated concentrations of sulfate ions and dissolved heavy metals as well as high acidity levels to groundwater and receiving surface water. Anaerobic biological processes relying on the activity of sulfate reducing bacteria are being considered for the treatment of AMD and other heavy metal containing effluents. Biogenic sulfides form insoluble complexes with heavy metals resulting in their precipitation. The objective of this study was to investigate the remediation of AMD in sulfate reducing bioreactors inoculated with anaerobic granular sludge and fed with an influent containing ethanol. Biological treatment of an acidic (pH 4.0) synthetic AMD containing high concentrations of heavy metals (100 mg Cu(2+)l(-1); 10 mg Ni(2+)l(-1), 10 mg Zn(2+)l(-1)) increased the effluent pH level to 7.0-7.2 and resulted in metal removal efficiencies exceeding 99.2%. The highest metal precipitation rates attained for Cu, Ni and Zn averaged 92.5, 14.6 and 15.8 mg metal l(-1) of reactor d(-1). The results of this work demonstrate that an ethanol-fed sulfidogenic reactor was highly effective to remove heavy metal contamination and neutralized the acidity of the synthetic wastewater.     

Influence of compost characteristics on heavy metal sorption from synthetic stormwater.

This paper has the aim to assess the ability of garden derived compost to remove dissolved heavy metal contaminants typically found in stormwater. Compost was found to have excellent chemical and physical properties for the sorption of dissolved metal ions (Cu2+, Pb2+ and Zn2+). Batch sorption data were used to determine the sorption efficiency of Cu (93%), Zn (88%) and Pb (97%) by compost. The relative sorption affinity of these metals by compost is found to be in the order of Pb2+ > Cu2+ Zn2+. The effect of different particle size fractions of compost upon the sorption of Cu was also investigated. Sorption conformed to the linear form of the Freundlich isotherm and can be considered favourable because the sorption intensity values obtained in this study are between 0.1 and 1. Compost with a smaller particle size fraction has larger surface areas and greater sorption than the larger particle size fraction. Compost derived from garden waste is efficient for removal of heavy metals from wastewater or treating water for industries.     

Effects of sorption, sulphate reduction, and Phragmites australis on the removal of heavy metals in subsurface flow constructed wetland microcosms.

The removal of Co, Ni, Cu and Zn from synthetic industrial wastewater was studied in subsurface flow constructed wetland microcosms filled with gravel or a gravel/straw mixture. Half of the microcosms were planted with Phragmites australis and half were left unplanted. All microcosms received low-strength wastewater (1 mg L(-1) of Co, Ni, and Zn, 0.5 mg L(-1) Cu, 2,000mg L(-1) SO4) during seven 14-day incubation batches. The pore water was regularly monitored at two depths for heavy metals, sulphate, organic carbon and redox potential. Sorption properties of gravel and straw were assessed in a separate experiment. A second series of seven incubation batches with high-strength wastewater (10 mg L(-1) of each metal, 2,000 mg L(-1) SO4) was then applied to saturate the substrate. Glucose was added to the gravel microcosms together with the high-strength wastewater. Sorption processes were responsible for metal removal during start-up, with the highest removal efficiencies in the gravel microcosms. The lower initial efficiencies in the gravel/straw microcosms were presumably caused by the decomposition of straw. However, after establishment of anaerobic conditions (Eh approximately -200 mV), precipitation as metal sulphides provided an additional removal pathway in the gravel/straw microcosms. The addition of glucose to gravel microcosms enhanced sulphate reduction and metal removal, although Phragmites australis negatively affected these processes in the top-layer of all microcosms.     

Effect of nickel ions on anaerobic methane production from water hyacinth

The effect of different concentrations of nickel ions (Ni(2+), 0, 10, 40 and 80 mg/L) on the anaerobic methane production of water hyacinth were investigated. Under these four concentrations, the methane production in 40 d was 2,275, 2,703, 3,210 and 2,481 mL, respectively. This situation illustrated that the Ni(2+) promoted the growth of hydrogen-producing acetic acid bacteria and methanogenic bacteria, even at high concentrations (i.e. 40-80 mg/L). The highest methane production per unit weight water hyacinth reached 206 mL/gTS with 40 mg/L Ni(2+). Meanwhile, the modified Gompertz and Logistic equations were applied to describe the effect on anaerobic culture of Ni(2+). According to these models, the values of methane production potential (mL) for four concentrations were in the following order: 40 mg/L (3,123.42 ± 60.08) > 10 mg/L (2,541.16 ± 46.94) > 80 mg/L (2,432.36 ± 40.18) > 0 mg/L (2,238.10 ± 31.90). According to the analysis of the digestate, the residual concentration of Ni(2+) was approximately 1.05-4.9 mg/L, which was relatively low compared with the Ni(2+) concentrations in the raw feedstock. The results would provide academic guidance and technical support for treatment of water hyacinth with an accumulation of heavy metals.     

Comparison of surface functional groups and metal uptake efficiency of rice husk harvested from different climatic zones

Rice husk (RH) is a very effective natural adsorbent for fast removal of heavy metal cations from water solutions. Application of RH for removal of some heavy metal ions, such as Ni, Zn, Mn, Co, Cu, Pb and Cd from water solutions has been studied and different maximum adsorption capacities and a variety of optimized conditions were reported in the literature. In this work, the efficiency of RH harvested from different climatic regions was studied. For this proposal, different RH samples were collected from three different climatic regions of Iran (nominated as RH1 to RH3); their removal efficiencies of heavy metal cations of Ni(2+), Cu(2+) and Cd(2+) were investigated and compared. The adsorption data at optimum conditions could be assessed well by both Langmuir and Freundlich models. Statistical analysis of the results of adsorption isotherms showed that different RH samples have different efficiencies in uptake of these heavy metal ions. The RH samples were characterized using Fourier transform infrared spectroscopy and Boehm titration, which indicated that amounts of functional groups differed between RHs that are grown in different climatic conditions.     

改性玉米芯吸附水中重金属离子的实验研究

以玉米芯做原料,用酒石酸改性,利用改性玉米芯吸附水中的Cu2＋ 和Pb2＋实验结果表明,实验中改性玉米芯吸附水中的Cu2＋ 和Pb2＋的吸附条件为：pH为5,吸附时间为120min,初始浓度为50mg／L,投加量为0．5g,在此条件下,改性玉米芯对Cu2＋ 和Pb2＋的吸附去除率分别为68％和94％,普通玉米芯对Cu2＋和 Pb2＋的吸附去除率分别为25％和65％。吸附过程更加能够符合准二级动力学方程,吸附规律能够更好地用Freundlieh方程所描述。改性玉米芯对重金属离子有选择吸附的能力,Pb2＋更加容易被吸附。本实验对于重金属的去除具有一定的参考价值。     

Co-precipitation of Ni, Cr, Mn, Pb and Zn in industrial wastewater and sediment samples with copper(II) cyclo-hexylmethyldithiocarbamate for their flame atomic absorption spectrometric determination

A co-precipitation technique for nickel(II), chromium(II), manganese(II), lead(II) and zinc(II) with the aid of copper(II) cyclo-hexylmethyldithiocarbamate was established. The influences of some analytical parameters such as pH, sample volume, amounts of cyclo-hexylmethyldithiocarbamate and copper(II) on the recovery of metal ions were investigated. The heavy metals in the precipitate were determined by flame atomic absorption spectrophotometry. The range of detection limits for the heavy metals was 0.003-0.005 mg/L. The atomic spectrometric technique with co-precipitation procedure was successfully applied for the determination of Ni, Cr, Mn, Pb and Zn in industrial wastewater and sediment samples from Ladipo stream in Lagos, Nigeria. The mean concentrations for these metals using co-precipitation procedure were not significantly different from corresponding concentrations obtained using spectrometric techniques without co-precipitation procedure.