超声和酸化对猪粪中Cu、Zn去除的影响

为了探讨利用超声和酸化来去除猪粪中的重金属,本文采用含固率为3％的猪粪溶液研究了超声和酸对其中cu、zn的去除以及影响因素。结果表明：酸可以去除猪粪中的cu、zn,且随着酸溶液加入量和JJn／k无机酸后反应时间的增加,猪粪中cu、zn的去除率提升,在猪粪溶液中加入酸调pH达到0．70,反应3h后猪粪中cu、zn的去除率可以达到58．70％、81．85％;超声也可以去除猪粪中的cu、zn,随着超声频率和超声时间的增加,猪粪中cu、zn的去除率提升,在40kHz超声90min,猪粪中cu、zn的去除率可分别达到87．43％、76．48％。超声与酸结合作用时,猪粪中cu、zn的去除率大于单独用酸或超声时的去除率。     

蚯蚓对猪粪重金属Cu、Zn的吸收及影响因素研究

由于饲料添加剂的使用,猪粪重金属污染已非常普遍,尤其是铜（Cu）、锌（Zn）污染最为明显。为了探讨利用蚯蚓萃取猪粪重金属Cu、Zn从而减少猪粪中重金属Cu、Zn含量的技术途径,采用室内接种法研究了赤子爱胜蚓（Eisenia foetida）对猪粪重金属Cu、Zn的吸收及影响因素。结果表明,蚯蚓对猪粪重金属Cu、Zn具有一定的吸收能力,富集系数分别为0.43、0.73; 物料C/N比、温度、湿度和蚯蚓接种密度均能影响蚯蚓对猪粪重金属Cu、Zn的吸收,在物料C/N比为17∶1～22∶1、温度为14-21℃、湿度为70%-75%、接种密度为10-20尾·200 g^-1物料（2.4-5.0 g·200 g^-1物料）条件下,蚯蚓对Cu、Zn的吸收量较高。     

砂姜黑土中重金属Cu、Cd、Zn形态分布与土壤酶活性研究

采用小麦农田取样,对土壤中的重金属运用连续提取方法,研究了皖北砂姜黑土中Cu、Cd、Zn的化学形态特征及其与四种土壤酶(过氧化氢酶、脲酶、蔗糖酶、中性磷酸酶)活性间的关系。结果表明:在砂姜黑土中,残留态Cu、Cd、Zn在总量中所占比例很高,交换态、有机态、碳酸盐结合态含量明显低于残留态。在三种元素中,Zn的化学形态变化趋势最为一致,表现为残留态>碳酸盐结合态>铁锰结合态>有机态>交换态;砂姜黑土中交换态Cu、Cd、Zn对脲酶活性有显著抑制作用,有机态Cu、Cd、Zn对过氧化氢酶表现为一定程度的促进作用。因此,在砂姜黑土壤中,把交换态Cu、Cd、Zn和脲酶以及中性磷酸酶的活性共同作为评价土壤Cu、Cd、Zn污染程度的主要生化指标是可行的。     

不同调理剂对猪粪堆肥重金属Cu、Zn、Cd形态的影响

选取玉米秸秆、木屑为调理剂,进行强制通风静态堆肥实验,以不添加调理剂为对照,研究调理剂对猪粪堆肥过程中重金属Cu、Zn、Cd活性的影响。结果表明,不添加调理剂的猪粪堆肥过程对重金属Cu、Cd具有一定的钝化效果,但可交换态钝化率分别仅为14.38%,15.43%,对重金属Zn具有一定的活化作用,增加有机肥土地利用过程中的环境风险。与对照相比,玉米秸秆和木屑作为调理剂不同程度地加强Cu、Zn、Cd的钝化效果,且以木屑表现较优的钝化作用,木屑对重金属Cu、Zn、Cd可交换态的钝化率分别达64.16%,56.24%,90.57%。LSD方差分析结果表明,木屑处理对重金属Cu的钝化效果显著优于秸秆处理和对照处理(p0.05),而秸秆处理和对照处理差异不显著(p0.05);木屑处理对重金属Zn的钝化效果显著优于秸秆处理和对照处理(p0.05),秸秆处理显著优于对照处理(p0.05);木屑处理和秸秆处理对重金属Cd的钝化效果显著优于对照处理(p0.05),而木屑处理与秸秆处理差异不显著(p0.05)。     

重金属Cd、Zn、Cu和Pb复合污染对土壤生物活性的影响

通过野外土样采集及室内培养试验(25℃),研究了云南东川铜矿区土壤酶和微生物特征,以及模拟重金属Cd、Zn、Cu、Pb复合污染对土壤微生物和酶活性的影响。结果表明,矿区土壤(距矿口0~800 m)重金属污染严重,Pb、Cd、Zn、Cu全量和有效含量是对照土壤(距矿口10 000 m)的3.7~141.0倍和2.2~773.2倍;距矿口越近,土壤有机质、有效氮、有效磷和速效钾含量及土壤pH亦越低,土壤酶活性和土壤微生物数量、微生物生物量碳和氮受到的抑制程度也显著增强。与对照土壤相比,距矿口0~800 m的土壤蔗糖酶、脲酶、酸性磷酸酶、过氧化氢酶和脱氢酶活性分别降低25.5%~47.3%、22.6%~74.2%、30.9%~83.1%、16.7%~69.1%和34.6%~92.3%;细菌、放线菌和真菌数量分别较对照下降30.5%~80.1%、8.1%~49.9%和3.3%~8.3%。土壤酶中的酸性磷酸酶和过氧化氢酶,土壤微生物中的细菌对重金属污染较为敏感。恒温(25℃)培养试验中,低量的Cd、Zn、Cu、Pb复合污染刺激了土壤酶活性和细菌、真菌、放线菌、微生物生物量碳和氮的数量,但高量的Cu、Zn、Pb、Cd复合污染使土壤酶活性、细菌、真菌、放线菌、微生物生物量碳和氮均显著下降。重金属Cd、Zn、Cu、Pb之间存在着一定的协同或拮抗作用,Cd、Zn、Cu和Pb之间在微生物生物量碳和氮上表现出明显的协同效应,Pb与Cd、Zn、Cu对细菌数量的复合效应机制为拮抗效应,Cd、Zn、Cu和Pb对真菌数量和放线菌数量的复合效应机制表现为协同效应和拮抗效应并存。     

尿素对玉米不同时期重金属Cu、Zn和Cd吸收的影响

通过盆栽试验研究污染红壤中施用不同用量尿素(0,100,200,400mg/kg)对玉米不同时期吸收重金属Cu、Zn和Cd的动态影响。结果表明:玉米生物量随着尿素施用量的增加而增加,且高用量尿素(400mg/kg)处理玉米生物量远高于其他处理。与对照相比,低中用量尿素(100mg/kg和200mg/kg)处理的根区土壤有效态重金属Zn、Cd含量随尿素用量的增加呈增大趋势,但对于高用量尿素处理呈现减小趋势。在玉米生长的60d里,随着生长期的延长,尿素不同处理玉米植株体内重金属含量有逐渐增加的趋势,同一时期尿素高用量处理下玉米植株体内重金属含量低于中低量尿素处理,但是由于获得高生物量使得高用量尿素处理玉米的地上部和根部重金属Cu、Zn、Cd移除总量最高。因此,酸性土壤上高用量尿素的施用,可强化玉米植株从污染土壤中移除重金属的能力。     

重金属Cd、Zn、Cu、Pb复合污染对土壤微生物和酶活性的影响

通过野外土样采集及室内测定,研究了云南东川铜矿区土壤酶和微生物特征,并采用盆栽试验研究了重金属Cd、Zn、Cu、Pb复合污染对土壤微生物和酶活性的影响。结果表明,距离矿口越近,土壤有机质、有效N、P、K的含量、土壤pH值亦越低,土壤酶活性和土壤微生物数量、微生物生物量C和N受到的抑制程度也增强,其中土壤酶中的酸性磷酸酶和过氧化氢酶,土壤微生物中的细菌对重金属污染较为敏感。盆栽试验中,Cd、Zn、Cu、Pb复合污染使白菜(Brassica rapapekinensis)生物量明显下降,且随复合污染程度的增加,白菜生物量下降幅度增加。Cd与Zn、Cu、Pb,Zn与Cd、Cu、Pb,Cu与Cd、Zn、Pb的复合效应机制为协同效应,而Pb与Cd、Zn、Cu的复合效应机制为拮抗效应。重金属Cu、Zn、Pb、Cd复合污染使土壤酶活性显著降低,但低量的Cd、Zn、Cu、Pb复合污染刺激了细菌、真菌、放线菌、微生物生物量C和N。重金属Cd、Zn、Cu、Pb对土壤酶活性和土壤微生物数量及微生物生物量C和N的复合效应机制表现出协同和拮抗效应。     

重金属Cu、Zn在施入畜禽粪的菜园土中的淋溶研究

The leaching characteristics of a garden soil may be greatly affected by application of poultry and livestock manures from intensive farming. Packed soil columns of a garden soil （CK） and the soils after respectively receiving 2% pig manure （PM）, chicken manure （CM）, and commercial organic manure （OM） were leached with 0.05 mol L^-1 Ca（NO3）2 and 0.01 mol L 1 EDTA solutions. The leachate EC （electric conductivity） values gradually increased at the beginning and then reached a stable value when the soil columns were leached with 0.05 mol L^-1 Ca（NO3）2 solution. The leachate EC values showed a peak-shape when leached with 0.01 mol L^-1 EDTA solution. In all the soil columns, the pH values of the leachates decreased with increase of displacement volumes when the Ca（NO3）2 solution was used. The total amounts of Cu and Zn eluted from the four soil columns were significantly correlated with the extracted soil Cu and Zn concentrations by 1.0 mol L^-1 NH4NO3, but were not correlated with the leachate dissolved organic carbon （DOC） contents. The Zn concentration in the leachate of the PM-treated soil column with 0.05 mol L^-1 Ca（NO3）2 solution was above the Quality Standard III for Ground Water of China （GB/T 14848-93, Zn 〈 1.0 mg L^-1）. When compared with 0.05 mol L^-1 Ca（NO3）2, the EDTA solution significantly accelerated Cu and Zn elutions in the manure-treated columns. This suggested that applying poultry and livestock manures from intensive farming to farmland might pose a threat to the groundwater quality.     

施用高浓度Cu、Zn沼液盆栽对土壤理化性状及重金属含量的影响

以潮土、红壤为供试土壤,以玉米、小白菜和紫花苜蓿为供试作物,采用盆栽试验的方法,研究了高浓度的Cu、Zn猪场沼液施用30天后(盆栽开始30天)对几种土壤理化性质和不同形态重金属含量的影响。结果表明,与不施用沼液的对照相比,施用高浓度Cu、Zn猪场沼液使潮土p H下降、红壤pH显著升高,土壤p H值的这一变化在3种供试作物上表现相同;土壤脲酶、磷酸酶活性显著提高,而过氧化氢酶活性变化因土壤类型而异;土壤交换态和铁锰态Cu、Zn含量显著提高,且在红壤上的提高幅度显著大于潮土。研究认为,高浓度Cu、Zn猪场沼液施用于农田在改善土壤肥力性状的同时,也会使土壤重金属Cu、Zn含量特别是有效态含量增加,导致潜在环境风险增大。     

三江平原白浆土中Fe、Mn、Cu和Zn生物有效性的研究

在三江平原上,测定 42 个小区中玉米、大豆、小麦籽实 Fe、Mn、Cu 和 Zn 含量和土壤中各形态 Fe、Mn、Cu 和Zn含量.通过相关分析和通径分析,探讨了土壤中各形态Fe、Mn、Cu 和 Zn 的生物有效性,旨在为该地区合理施用微量元素提供科学依据.试验结果表明,玉米、大豆和小麦籽实含 Fe、Mn、Cu 和 Zn 量与土壤中有效态和交换态 Fe、Mn、Cu和Zn含量呈显著或极显著正相关.有机态 Fe、Mn、Cu 和 Zn含量与玉米、大豆和小麦籽实Fe、Mn、Cu 和 Zn含量也有很好的相关关系.交换态对有效态 Fe、Mn、Cu 和 Zn 影响最大,其次是有机质结合态.铁锰氧化物结合态 Fe、Cu 对有效态 Fe、Cu 及碳酸盐结合态 Mn、Zn 对有效态 Mn、Zn 具有一定正效应.而残留态 Fe、Cu 对有效态 Fe、Cu 和铁锰氧化物结合态 Mn 对有效态 Mn 产生负效应.     

一种磁性固体螯合材料对农田土壤Cd的移除修复效果研究

通过室内模拟试验,开展了投加一种磁性固体螯合材料(Magnetic solid chelator,MSC)并进行磁选回收对农田土壤Cd的移除修复效果、MSC回收率及磁选物质螯合捕集Cd能力的研究。结果表明,投加0.4%~1.2%的MSC材料并进行磁选回收对总Cd和有效态Cd的去除率分别为15.91%~17.69%和33.33%~50.26%,而MSC的回收率在74.01%~94.33%之间,有随投加量增加而增加并逐渐趋于稳定的趋势;磁选物质(主要为MSC材料)螯合吸附的Cd含量在19.31~25.72 mg·kg~(-1)之间,在0.4%处理中最高,显著高于0.8%、1%和1.2%处理,有随MSC材料回收量的增加而降低的趋势。0.8%和1.2%投加量时磁选物质螯合捕集的Cd能较好地解释土壤被去除的那部分Cd。处理后水样中的Cd含量低于我国地表水环境质量标准(GB 3838—2002)中的Ⅰ类标准(0.001 mg·L~(-1)),不会成为新的污染源。因此,MSC材料对农田土壤Cd具有一定的移除修复效果,为农田土壤重金属修复提供了一种新方法。     

几种植物去除污染水体中养分效果研究

对城市尾水和人工模拟富营养化水体进行了静态培养试验.通过比较不同植物对城市尾水中氮、磷去除效果,以及它们在不同磷浓度条件下对不同形态氮素去除效果研究,目的在于筛选出适合治理富养分污染水体的植物品种.研究结果表明,空心菜(Ipomiea aquatica)、酸模(Rumex acetosa)、莎草(Cyperus glomeratus)3种植物都能很好地吸收尾水中的营养物质,且生长状况良好.经3种植物处理的城市尾水,其氮、磷浓度随水培时间的增加而降低.莎草、酸模对污水中TN的去除率达90%以上,其中莎草最高,达93.4%;空心菜对全磷的去除率最高达76.9%.NH_4~+-N在处理前期变化显著,且莎草的净化效果最好达94.4%;污水中NO_3~--N含量随着水培时间的增加而逐渐下降,但在试验后期NO_3~--N又有所增加.酸模去除NO_3~--N效果最好,达65.4%.另外3种植物对NH4+-N和NO_3~--N都具有一定的吸收作用,并且优先吸收NH_4~+-N.且从对于NH_4~+-N和NO_3~--N净化效果看,莎草>酸模>空心菜.     

Enhancement of Biological Nitrogen Removal from Wastewater by Low-Intensity Ultrasound

This paper investigated the influence of low-intensity ultrasound in biological nitrification and denitrification. The results showed that the nitrification activity of activated sludge could not be promoted significantly by ultrasound in 5–40 min with intensities ranging from 0.1 to 1.2 W?cm^?2. It suggested the fact that nitrifying bacteria were insensitive to ultrasound, possibly related with their specific structures of cell membrane and ways of metabolism. Whereas, biological denitrification was enhanced quite remarkably by ultrasound and the optimal results were achieved at the ultrasonic intensity of 0.2 W?cm^?2 and the irradiation time of 10 min. Compared with the control without ultrasonic irradiation, it took 5 h for the enhancement of denitrification rates induced by the optimum ultrasound to reach its peak level (16%). Therefore, ultrasound with intensity of 0.2 W?cm^?2 could be employed in the biological denitrification system for 10 min every 5 h to obtain the optimal effect theoretically.     

活性氧化铝去除不同浓度污水中磷的研究

通过批量吸附实验明确活性氧化铝吸附剂量、pH值、温度等不同条件下对2种浓度(2 mg/L和180mg/L)模拟污水中磷酸盐去除效果进行研究,分析活性氧化铝吸附磷酸盐的穿透曲线,并在此基础上对其吸磷机制进行分析.结果表明:随着活性氧化铝用量增加,2种浓度磷酸盐平衡浓度逐渐降低,当活性氧化铝剂量分别增加到3 g/L和160 g/L时,污水中磷去除率均达90％以上;在pH值为5.0,温度为40℃时的吸附条件下,活性氧化铝对2种浓度模拟污水中磷的吸附效果最好;穿透曲线表明,采用1.0 L/d低流速条件下,连续运行20 h时间,180 mg/L磷酸盐的穿透时间为16 h;对于2 mg/L的磷酸盐废水,在3.8 L/d流速下连续运行16d时发生穿透;利用扫描电镜(SEM),红外光谱(FTIS)和X衍射光谱对吸附前后活性氧化铝表面特征分析,证明了活性氧化铝对磷酸盐存在化学吸附作用.因此利用活性氧化铝可实现对污水中不同浓度磷酸盐的吸附作用.     

Zinc Removal from the Aqueous Solutions by the Chemically Modified Biosorbents

Biosorbents are the natural origin adsorbents, which popularity in environmental engineering is steadily increasing due to their low price, ease of acquisition, and lack of the toxic properties. Presented research aimed to analyze the possibility of chemical modification of the straw, which is a characteristic waste in the Polish agriculture, to improve its biosorption properties with respect to removal of selected metals from aquatic solutions. Biosorbents used during the tests was a barley straw that was shredded to a size in the range of 0.2–1.0 mm. The biosorption process was performed for aqueous solutions of zinc at a pH 5. Two different modifications of straw were analyzed: esterification with methanol and modification using the citric acid at elevated temperature. The results, obtained during the research, show a clear improvement in sorption capacity of the straw modified by the citric acid. In the case of straw modified with methanol, it has been shown that the effectiveness of zinc biosorption process was even a twice lower with respect to the unmodified straw. Moreover, it was concluded that the removal of analyzed metals was based mainly on the ion-exchange adsorption mechanism by releasing a calcium and magnesium ions from the straw surface to the solution.

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Graphical Abstract ?

     

Removal of Ammonium and 4-Methylphenol from Synthetic Wastewater by Cell-Free Extracts of Nitrifying Sludge

Fluoroquinolone antibacterial agents (FQs) are the most commonly detected antibiotics in soil/groundwater which cause chronic effects on human beings as well as aquatic ecosystems. The current situation of the regulation, occurrence, fate, and sources of FQs in soil/groundwater was systematically analyzed in this paper. And then, the important factors affecting milligram per liter concentration of FQs sorption in soil, such as pH, cation exchange, clay minerals, organic content, surface complexation, and microbial degradation or transformation, were summarized. Actually, nanogram-microgram per liter concentration is detected frequently in soil/groundwater by far. Due to the extensive application of FQs and its relatively stable physicochemical characteristics, the higher concentration in soil/groundwater would appear in the coming decades which may exert a threat to freshwater and human beings. To the knowledge of the authors, no full-scale fate, occurrence, spatial, and temporal variations of FQs in soil/groundwater have been reported in the scientific literature. Therefore, it is recommended that more comprehensive studies are required to fill knowledge gaps in low-concentration transport, fate and occurrence, spatial, and temporal variations of FQs in soil/groundwater and their potential risk assessment to human and ecosystem.

     

Mechanistic Consideration of Zinc Ion Removal by Zero-Valent Iron

Mechanism of zinc iron removal by zero-valent iron was discussed through zinc removal responses to several operational conditions of a packed column reactor with zero-valent iron powder. The adsorption isotherm observed implied that a kind of chemisorption was responsible for zinc removal. Zinc removal by zero-valent iron was enhanced by dissolved oxygen and ferric ion addition. However, it was deteriorated under acidic pH. In addition, zinc adsorbed on zero-valent iron was eluted by a reducing agent such as citric acid, whereas the zinc was not eluted by diluted sulfuric acid. Consequently, the zinc removal mechanism by zero-valent iron was inferred to be as follows: Zero-valent iron was firstly corroded and oxidized into ferric ion by dissolved oxygen. The ferric ion was precipitated as iron hydroxide onto the surface of the zero-valent iron powder. Zinc ion was adsorbed on and/or coprecipitated with the iron hydroxide. The iron hydroxide was finally oxidized and transformed into iron oxides.     

垂直流-水平潜流一体化人工湿地对菜地废水的净化效果

广州市番禺区东升农场菜地废水未经处理直接排入水生植物塘,最终流入附近河流,由于菜地废水水质较差,对其造成了严重的污染,严重威胁了附近居民的饮水安全。为了提高菜地出水水质,减轻对河流的污染,通过构建垂直流-水平潜流一体化人工湿地,对菜地废水进行净化处理。湿地经过9个月的运行,结果显示,湿地对COD、NH4＋-N和TP的平均去除率分别达56.40%、79.09%和79.79%以上,COD、NH4＋-N和TP出水平均浓度分别为9.45、0.47mg.L-1和0.06mg.L-1,均达到《地表水环境质量标准》（GB3838—2002）Ⅱ类水质标准。湿地对TN的平均去除率较低,仅为35.08%,通过补充甘蔗叶作为碳源,湿地对TN的平均去除率显著提高,但随着碳源投加量的增加,去除率逐渐降低。本实验碳源投加量以1.62kg.m-3为宜,TN的平均去除率最高,达80.85%,出水TN平均浓度从3.06mg.L-1降低至0.90mg.L-1。