铜、镉、铅离子对水螅摄食行为的抑制作用

参照GB 3838—2002《地表水环境质量标准》中Ⅰ类标准(GB-Ⅰ)的重金属限量值,探索了Cu2+、Cd2+、Pb2+浓度对水螅摄食行为的抑制作用。结果发现,这3种离子抑制水螅摄食行为的2 min最低可见效应浓度ρLOE,Cu2+的低于其GB-Ⅰ的限量值,Cd2+、Pb2+的略高于其GB-Ⅰ的限量值;与24 h暴露于相同浓度重金属溶液的ρLOE接近。Cu2+的2 minρLOE与7 d暴露于Cu2+的ρLOE相同。结果提示,利用水螅摄食行为检测水体微毒性的方法比以往方法更简便、快速、准确,在水体微毒检测方面具有广泛的应用前景。     

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。     

锌离子对菖蒲的胁迫反应研究

采用水培法,以Hoagland溶液为基础培养液,研究Zn2+胁迫对菖蒲幼苗生长状况、细胞渗透性、过氧化物酶(POD)活性、超氧化物歧化酶(SOD)活性、叶绿素以及脯氨酸质量比的影响。结果表明,Zn2+胁迫下菖蒲幼苗生长受到严重影响;随着Zn2+质量比的增加,叶片电导率不断增大;POD、SOD活性均高于对照,并且呈现先升高后降低的正相关趋势;叶绿素的质量比显著降低,与Zn2+质量比呈负相关趋势;脯氨酸质量比则一直呈上升的变化趋势。研究结果说明,酶活性的升高是由于菖蒲对Zn2+胁迫做出的应激反应,而高质量比Zn2+却对菖蒲的保护酶活性有抑制作用。     

天然核桃壳对废水中Cd~(2+)和Pb~(2+)的吸附热力学研究

采用批处理技术研究了天然核桃壳吸附废水中Cd2+和Pb2+的主要影响因素,如p H值、核桃壳用量和离子初始浓度等因素,并探讨了吸附等温线及吸附热力学。研究表明,天然核桃壳对Cd2+和Pb2+的最大吸附量分别为12.5mg/g和38.02mg/g。天然核桃壳吸附Cd2+的过程对Freundlich方程和Langmuir方程的拟合效果都较好;吸附Pb2+的过程则对Freundlich方程的拟合效果要好于Langmuir方程。热力学分析表明,天然核桃壳对Cd2+和Pb2+的吸附属自发吸热过程,且较易发生。     

土液比对Pb~(2+)的吸附动力学影响研究

探明Pb2+吸附动力学过程,是分析污灌区土壤Pb2+截留能力的理论基础。基于600 mg/L的Pb2+溶液和马鞍山高龙背粉沙质壤土,开展不同土液比条件下的Pb2+吸附动力学试验。结果表明,与常规吸附动力学试验相比,同一土液比情况下的吸附动力学曲线波动性较大,首次波动幅度随土液比的减小逐渐增大,从波动开始到基本稳定所需的时间随土液比的减小逐渐增加,吸附量随着土液比的减小逐渐增大,吸附率却逐渐减小。     

镧对黄河包头段水体中混合藻类的影响

选取黄河水体中含量较多的稀土元素镧(La)作为研究对象,以引黄水库富营养化水体中的混合藻类为受试生物,进行藻类的培养试验,探讨了稀土元素对黄河水体中混合藻类生长生理的影响规律。结果表明:低浓度(2 mg/L)La对藻类的生长具有刺激作用;高浓度(50 mg/L)La对藻类的生长具有抑制作用,且浓度越高抑制作用越强;中等浓度(5～10 mg/L)La对藻类生长的刺激与抑制作用受光照强度影响;La在任何浓度下都会改变藻类种群结构、抑制水体中藻类的生物多样性,且浓度越高,抑制作用越强;引黄水库每年3月份藻类的爆发及黄河水体的富营养化可能与水体中的La有关。     

Zn2+对蛋白核小球藻生长影响的实验研究

通过藻类增长潜力实验,分别以蛋白核小球藻的光密度值、叶绿素a值、比增长率以及光合速率和呼吸速率为指标,对应分析了不同浓度的Zn2+对蛋白核小球藻生长的影响。在本实验条件下,Zn2+质量浓度低于0.1μg/L对蛋白核小球藻的生长有限制作用;在1~100μg/L之间则可促进蛋白核小球藻的增殖,其中在50μg/L时藻类生长最快;达到1 mg/L以上表现出对蛋白核小球藻生长的抑制作用,达到100 mg/L时,其对蛋白核小球藻的毒性效应可以导致藻类生长停止。实验结果表明,在景观水体中适当浓度的Zn2+是一定条件下触发或抑制蛋白核小球藻爆发性增殖的重要因子之一,在研究再生水应用于景观水体富营养化防控中应该予以重视。     

不同价态铁对四尾栅藻生长的影响及机理探讨

采用实验室模拟培养的方法,分别培养初始Fe2+和Fe3+为0.2 mg/L、0.4 mg/L、0.5mg/L、0.7mg/L时的四尾栅藻。结果表明:四尾栅藻对于铁的吸收利用主要包括蛋白转运和铁置换两个过程,对于Fe2+的吸收利用以蛋白转运为主,通过修正Shaked铁吸收模型,蛋白转运进一步分为Fe3+还原和Fe2+转运两个步骤。铁的不同价态对四尾栅藻的生长影响差异明显,Fe2+较之Fe3+表现出更强的藻利用时效,同样的游离态浓度下,藻增殖速度快,藻峰值更高。四尾栅藻倾向于优先吸收Fe2+。四尾栅藻的生长环境存在一个最佳的Fe2+浓度范围,在初始Fe2+为0.4mg/L条件下,四尾栅藻生长速率最快,藻峰值最大,分别达到0.136 7个/(L·d)和2.9×108个/L。当Fe2+大于0.4mg/L时,抑制作用不明显,但增殖速率有所减缓。营养充足条件下,四尾栅藻生长曲线满足y=Aln(x)+B,A、B系数随着初始Fe2+浓度的不同而不同。     

非活性红色链霉菌吸附废水中Pb2+机理分析

采用吸附等温方程、扫描电镜以及红外光谱仪等测试分析方法对红色链霉菌废菌体吸附废水中Pb2+的机理进行分析和探讨。结果表明,强碱的处理可以明显提高废菌体的吸附性能;红色链霉菌细胞壁上的—COO—、C—H和O—H可能是吸附铅离子的主要基团;红色链霉菌吸附Pb2+的过程可能是一个以表面络合反应为主的物理化学吸附过程。     

再生水与保水剂对作物种子萌发及幼苗生长影响的试验研究

研究了再生水、保水剂及再生水与保水剂的相互作用对小麦、玉米、黄瓜、甜瓜及西瓜等5种作物种子萌发及幼苗生长的影响。结果表明,除了保水剂对玉米发芽势有显著抑制作用、再生水+保水剂对玉米发芽率有显著促进作用外,不同处理对作物种子发芽势和发芽率的影响均未达到显著水平。不同处理对第5天苗高的影响,不同作物种子间差异较大:保水剂对玉米有极显著的抑制作用,对其他作物种子无显著影响;再生水对玉米、甜瓜有极显著的抑制作用,对西瓜有显著的抑制作用,对黄瓜有极显著的促进作用,对小麦无显著影响;保水剂+再生水对玉米有极显著的抑制作用,对黄瓜有极显著的促进作用,对其他作物种子无显著影响。     

凉水河污染对土壤和地下水的影响

在凉水河下游取河床底泥及河床下部土样,分析其NH3-N、磷和有机物的变化,发现底泥对NH3-N和磷的去除发挥了很大作用,分别是下部土壤吸附量的10倍和1倍多;土中5种氯代烃均有检出,是河水长期渗漏积累的结果。凉水河流域内的野外试验结果表明,凉水河对地下水存在污染,污染组分主要是CODCr,NH3-N也有一定污染,其他无机污染组分如NO3-N,Cr6+,TP和Pb2+对地下水的影响较小,氯代烃对地下水也有一定影响。据推测,凉水河污染对地下水的影响范围大概在河两侧80 m范围内。     

Enhancement of removal efficiency of heavy metal ions by polyaniline deposition on electrospun polyacrylonitrile membranes

This paper describes the preparation of a membrane of polyacrylonitrile(PAN) and its corresponding membrane coated with polyaniline(PANI) for the adsorption of heavy metal ions.Scanning electron microscopy micrographs revealed that all the membranes exhibited nanofibrous morphology.The prepared membranes were characterized by Fourier transform infrared spectroscopy(FTIR).The prepared membranes were used as an adsorbent for hazardous heavy metal ions Pb~(2+) and Cr_2 O_7~(2-).The adsorption capacity and the removal efficiency of the membranes were examined as function of the initial adsorbate concentration and pH of the medium.Coated membranes with PANI showed better adsorption performance and their direct current(DC) conductivities were correlated to heavy metal ion concentrations.Adsorption isotherms were also performed,and the adsorption process was tested according to the Langmuir and Freundlich models.The regeneration and reuse of the prepared membranes to re-adsorb heavy metal ions were also investigated.The enhancement in adsorption performance and reusability of PANI-coated membranes in comparison with non-coated ones is fully discussed.The results show that the maximum adsorption capacities of lead and chromate ions on the PANI-coated membranes are 290.12 and 1 202.53 mg/g,respectively.     

污染河流还清室内试验研究

在污水灌入土柱试验的基础上,用自来水代替试验配水,模拟污染河流还清后对地下水的影响。试验结果表明:清水回灌会很明显地把污染河流下部渗透介质中的COD,NH4+带到地下水中,造成地下水污染,其进入地下水的量取决于渗透介质中截留的COD和NH4+的量;清水回灌仅会把河床下部渗透介质中少量的Cr(Ⅵ),TP和苯系物带到地下水中,成为地下水有机污染的一个来源;Pb2+一般不会被带到地下水中。     

A novel combined electrochemical-magnetic method for water treatment

Electrocoagulation (EC) is a wastewater treatment process in which aqueous pollutants can be removed by adsorption, entrapment, precipitation or coalescence during a coagulation step produced by electrochemically generated metallic species. When using Fe as the sacrificial electrode, Fe(2+) and Fe(3+) ions are formed. As Fe(3+) species are paramagnetic, this property can in principle be used to facilitate their removal through the application of a magnetic field. In the present work we present a proof-of-concept for a combined electrochemical-magnetic method for pollutant removal. For this approach, the amounts of Fe(2+) and Fe(3+) produced in an EC cell at various voltages were measured by spectroscopic methods to confirm that Fe(3+) species predominate (up to 84%). The effectiveness of the presence of a magnetic field in the precipitation of coagulants from a suspension was confirmed by monitoring the turbidity change versus time with and without exposure to a magnetic field, up to a 30% improvement.     

Modification of granular activated carbon using low molecular weight polymer for enhanced removal of Cu(2+) from aqueous solution.

Palm shell activated carbon was modified via surface impregnation with polyethyleneimine (PEI) to enhance removal of Cu(2+) from aqueous solution in this study. The effect of PEI modification on batch adsorption of Cu(2+) as well as the equilibrium behavior of adsorption of metal ions on activated carbon were investigated. PEI modification clearly increased the Cu(2+) adsorption capacities by 68% and 75.86% for initial solution pH of 3 and 5 respectively. The adsorption data of Cu(2+) on both virgin and PEI-modified AC for both initial solution pH of 3 and 5 fitted the Langmuir and Redlich-Peterson isotherms considerably better than the Freundlich isotherm.     

Optimization of a bacterial consortium for nitrobenzene degradation

Three bacterial strains, Arthrobacter sp. NB1, Serratia sp. NB2 and Stenotrophomonas sp. NB3, were isolated from contaminated sludge by using nitrobenzene as a sole source of carbon and nitrogen. It was observed that all three strains could degrade nitrobenzene at 400 mg/L initial concentration and mixed-cultivation of these strains could enhance the degradation of nitrobenzene compared with mono-cultivation. Mixture design was used for adjusting the proportions of each strain and the optimal ratio of inoculation size was NB1:NB2:NB3 = 4:4:5, where the nitrobenzene degradation percentage was two times higher than for by the single strain. The results of Plackett-Burman design indicated that Mg(2+), Ca(2+), Fe(2+), Zn(2+) and Mn(2+) had a positive effect on the degradation of nitrobenzene, while Cu(2+) and Co(2+) had a negative effect on it.     

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.     

Post-treatment of biologically treated wastewater of agrochemical industry by sulfated chitosan composite nanofiltration membrane

The objective of this study is to treat the biologically treated wastewater using sulfated chitosan/ polyacrylonitrile (PAN) composite nanofiltration (NF) membrane to improve agrochemical industry wastewater quality for reuse. Although biological treatment is quite efficient, the wastewater does not meet the reuse criteria. Hence, further treatment to improve the water quality is investigated. Sulfated chitosan composite NF membranes, having a PAN ultrafiltration membrane as the substrate, are prepared by coating and cross-linking methods. The effects of membrane preparation conditions on the rejection and permeation performance of the membranes are studied. The new membranes are characterized by NMR and scanning electron micrograph. Wastewater from agrochemical industry contains high concentrations of organic matter, color, heavy metals and other toxic substances. The operating variables studied are applied pressure (3-15 atm) and feed flowrate (4-16 L/min). It is found that the observed rejection (R(o)) increases with increase in feed pressure at constant feed flowrate. The rejection of cations follows the sequence: R(o)(Zn2+) > R(o)(Ni2+) > R(o)(CU2+) > R(o)(Cd2+) for wastewater. It is observed that the order of solute rejection sequence is inversely proportional to the diffusion coefficients.     

生物固锰除锰技术的微生物学研究

Mn~(2+)氧化细菌的微生物学研究是与除锰工艺直接相关的一个领域。已经发现许多细菌具有锰氧化能力。目前的研究工作基本局限在细菌形态观察和细胞悬液、细胞破碎液的活力动力学测量。因此研究了分离得到的Mn~(2+)氧化细菌,包括其形态、生理研究。同时对其氧化活性进行了测量。可以确认,滤池中存在着大量的Mn~(2+)氧化细菌,细菌参与了除锰。