氧化亚铁硫杆菌浸出线路板中铜的研究

从煤堆积水中分离得到氧化亚铁硫杆菌,利用该菌种对线路板中的铜进行了浸出实验.研究了不同线路板粉末添加量对浸出效果的影响,观察了浸出过程中pH和氧化还原电位(Eh)的变化,结果表明添加量为10 g/L和20 g/L时,在15 d内线路板Cu几乎全部浸出,而50g/L和100g/L在15 d内亦有较高的浸出效率,并呈持续上升趋势.     

氧化亚铁硫杆菌浸出线路板中铜的研究

从煤堆积水中分离得到氧化亚铁硫杆菌，利用该菌种对线路板中的铜进行了浸出实验。研究了不同线路板粉末添加量对浸出效果的影响，观察了浸出过程中pH和氧化还原电位（Eh）的变化，结果表明添加量为10g／L和20g／L时，在15d内线路板Cu几乎全部浸出，而50g／L和100g／L在15d内亦有较高的浸出效率，并呈持续上升趋势。     

氧化亚铁硫杆菌浸提废旧线路板铜的浸出率与时间的关系

探讨氧化亚铁硫杆菌SW-02(Thiobacillus ferrooxidans SW-02)浸提废旧印刷线路板Cu的适宜浸出时间,对Cu的浸出率与时间的关系进行了研究。通过摇瓶培养的方式,在30℃,摇床转速为170 r/min条件下进行浸出实验,按不同时间间隔取样测定溶液Cu2+浓度,pH值与氧化还原电位。分析发现,线路板加入量在30 g/L及以上时,浸出40 h后浸出反应停止,而线路板加入量在15 g/L时,浸出40 h后Cu的浸出率达到70%,继续浸出,浸出率不再显著增加。研究结果表明,铜的适宜浸出时间为40 h。     

一株氧化亚铁硫杆菌的分离及其浸出废旧线路板中铜的效果

从广东某硫铁矿山酸性废水中分离到一株嗜酸性细菌,经形态观察、生理学和近全长16S rRNA基因分析鉴定为氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans,简称A.ferrooxidans),命名为Z1。该菌与GenBank中菌株A.ferrooxidansCMS等处在系统发育树的同一分支,16S rRNA基因序列相似度均为99%。菌株Z1生长的最适pH值和温度分别为2.25和30℃,对数生长期处于第18～30小时,Fe2+平均氧化速率达到0.2307 g/(L.h),经驯化后能耐受15 g/L的废旧线路板金属富集体。浸出实验结果表明,在起始pH值为2.25、起始Fe2+浓度为9 g/L、接种量为10%、金属富集体投加量为15 g/L的条件下,菌株Z1能在62 h内浸出废旧线路板中99.3%的铜。与生物浸出效果类似,过滤除菌的滤菌液处理能在86 h内浸出96.0%的铜。而不接种上述细菌的9K培养基无菌浸出对照134 h铜的浸出率仅为61.3%。因此,菌株Z1可作为浸出废旧线路板中有价金属的潜在有效菌株。     

氧化亚铁硫杆菌浸出线路板中铜及过程中铁的变化研究

从煤堆积水中分离得到氧化亚铁硫杆菌,利用该菌种对线路板中的Cu进行了浸出实验.研究了不同线路板粉末添加量对浸出效果的影响,在220 mL溶液中添加量为2.2、4.4 g时Cu的浸出率很快达到了90%,而添加量为11.0、22.0 g时浸出率表现了缓慢上升,在15 d左右达到了90%.观察了浸出过程中铁浓度及价态的变化,结果表明,浸出初期随着添加量的增加,Fe2 增加明显,但是随着浸出时间的推移,Fe3 、Fe2 和总Fe都呈现降低趋势.     

废旧印刷线路板矿浆电解过程中金属的浸沉规律

以废旧印刷线路板粉末(WPCBs)为原料,采用矿浆电解法回收WPCBs中金属,研究CuSO_4·5H_2O浓度、NaCl浓度、H_2SO_4浓度、电流大小、WPCBs加入量和电解时间对矿浆电解过程中金属的浸出和电沉积规律的影响。结果表明:CuSO_4·5H_2O浓度、WPCBs加入量对WPCBs中金属浸出率影响不大,增加NaCI浓度、H_2SO_4浓度、电流和电解时间有利于WPCBs中金属浸出;增加NaCl浓度、H_2SO_4浓度和电解时间有利于WPCBs中金属沉积,而增加CuSO_4·5H_2O浓度、WPCBs加入量和电流不利于金属沉积。当CuSO_4·5H_2O浓度、NaCl浓度、H_2SO_4浓度、电流、WPCBs加入量和电解时间分别为30 g·L~(-1)、60 g·L~(-1)、170 g·L~(-1)、0.5A、3g和9h时,WPCBs中金属的浸出率和沉积率分别为92.28%和67.04%。     

废弃LCD面板金属铟的超声协同浸出

随着LCD报废数量的逐年增多,废弃LCD面板所含金属铟的回收再用已成为铟资源回收领域急需解决的问题。为提高废弃LCD面板金属铟的回收效率,研究提出利用超声对其进行协同浸出,以硫酸为浸出液考察超声及不同反应条件对铟浸出效率的影响。研究结果显示,超声协同能有效提高铟的浸出效率,在实验参数范围内铟的浸出率随超声功率、反应温度及酸浓度的增加而增大,随物料粒径增大而减小。在超声功率为800 W、反应温度60~70℃、硫酸浓度0.5mol/L、物料粒径小于0.5 mm条件下,浸出反应5 h铟的浸出率可达74.1%。在此基础上,研究进一步分析了超声对铟浸出反应的协同作用机制,指出热学与机械作用是超声促进废弃LCD面板金属铟浸出反应进行、提高铟浸出效率的主要作用机制。     

集成膜法回收钛白废酸中硫酸

对扩散渗析回收钛白废酸中硫酸与减压膜蒸馏联合浓缩废酸进行了实验研究。结果表明,扩散渗析的酸回收率、回收酸浓度和亚铁泄漏率随料液流量的增大而减小,而酸渗析速度及酸对硫酸亚铁的分离系数却随之增大;随水料比的增大,酸回收率、酸渗析速率和亚铁泄漏率增大,回收酸浓度及酸对硫酸亚铁的分离系数减小;在选定实验条件下,硫酸浓度为1.92 mol/L的钛白废酸,先经扩散渗析进行酸盐分离,然后经减压膜蒸馏浓缩,可得到硫酸质量百分浓度为65%以上的浓缩废酸,达到了返回钛白生产使用的要求。     

类柱试验中焚烧飞灰浸出特性研究

通过类柱试验研究焚烧飞灰的浸出规律.结果表明,随着流入系统中酸溶液体积的增加,系统pH先升高而后下降;在整个系统中,Ca的浸出质量浓度很高;Cr的浸出质量浓度要高于Cd、Cu、Zn、Pb和Ni,随着反应时间的推进,它们的浸出质量浓度都随着流入系统中酸溶液体积的增加而逐渐降低;在同一时间浸出质量浓度曲线上,从系统的上游到下游,浸出质量浓度呈增加趋势,如Cu的浸出质量浓度在系统上游(单元1)为60.2 μg/L,而在系统下游(单元10)为158.0 μg/L.     

外源营养物质对土壤中六氯苯厌氧降解效能的影响

实验以水淹法营造厌氧环境,研究了4种外源营养物质葡萄糖、乙酸、硫酸亚铁、氯化铁及其组合在不同添加浓度下对实际工业污染土壤中六氯苯厌氧降解效能的影响。研究结果表明,在低添加浓度下,无论单独添加还是组合添加营养物质都能明显强化六氯苯的厌氧降解效能,其强化能力大小顺序为:乙酸+硫酸亚铁>乙酸>葡萄糖>乙酸+氯化铁>氯化铁>硫酸亚铁。当乙酸和硫酸亚铁的添加浓度分别为8 g/L和1 g/L时,六氯苯的降解率达到最大,为62.72%,乙酸与硫酸亚铁的组合对六氯苯的降解起到了协同降解的作用。此外,研究还对高添加浓度下,六氯苯降解效能降低的原因进行了初步探索。     

氧化亚铁硫杆菌浸铜作用研究

为研究氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans,简称A.f)对铜浸出的作用,从某煤堆积水中分离得到A.f菌,利用该菌对铜进行浸出实验,设置3个处理,3个处理的浸出液分别为9 K培养基(简称S),成熟菌液(简称MS)和过滤除菌液(简称FS)。结果表明,3个处理中铜都得到了浸出,浸出铜浓度按S、FS和MS依次递增分别为4 433、5 377和6 296 mg/L;浸出初期,MS中的铜,浸出速度最快,过滤除菌液中次之,而培养基中的速度比较稳定,比前两者均慢,24 h后三者浸铜速度趋近一致;三者中pH、Eh变化相似,pH均先升高至3.4左右保持相对稳定,Eh均先迅速下降至280 mV后保持稳定。由实验可知,氧化亚铁硫杆菌主要在浸出初期促进了铜的浸出,且菌液中溶解氧氧化Fe2+以及酸性条件下氧化Cu0对铜的浸出作用不容忽视。     

氧化亚铁硫杆菌浸铜研究及胞外多聚物的作用

为了获得氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans,A.f)以及胞外多聚物(extracellular polymeric sub-stances,EPS)对铜浸出的作用结果,进行了透析袋实验,设置2个处理,2者的浸出液均为成熟菌液,但一个将铜片装入透析袋中以隔离A.f及EPS与铜的直接接触。结果表明:(1)菌液的处理和加透析袋的处理中铜都得到了浸出,240 h铜的浸出浓度分别为6 796 mg/L和1 366 mg/L,可知A.f及EPS与铜片直接接触能促进铜的浸出;(2)透析袋的处理中Fe3+保持较高浓度,说明Fe3+与EPS络合后被阻挡在透析袋外面从而不能与铜反应,可知EPS在A.f浸铜中起了媒介载体的作用;(3)2者的SEM图表明无透析袋的处理A.f与铜在实验初期发生了吸附,实验后期则无,实验初期铜快速浸出是由于传质距离短,而后期速度变缓是由于传质距离增大。     

Leaching behavior and chemical stability of copper butyl xanthate complex under acidic conditions

Although xanthate addition can be used for treating copper-containing wastewater, a better understanding of the leaching toxicity and the stability characteristics of the copper xanthate complexes formed is essential. This work was undertaken to evaluate the leaching behavior of copper xanthate complex precipitates by means of toxicity characteristics leaching procedure (TCLP) and semi-dynamic leaching test (SDLT) using 1 N acetic acid solution as the leachant. Also, the chemical stability of the copper xanthate complex during extraction has been examined with the studying of variation of chemical structure using UV-vis, Fourier transform infrared and X-ray photoelectron spectroscopies (XPS).Both TCLP and SDLT results showed that a negligible amount of copper ion was leached out from the copper xanthate complex precipitate, indicating that the complex exhibited a high degree of copper leaching stability under acidic conditions. Nevertheless, chemical structure of the copper xanthate complex precipitate varied during the leaching tests. XPS data suggested that the copper xanthate complex initially contained both cupric and cuprous xanthate, but the unstable cupric xanthate change to the cuprous form after acid extraction, indicating the cuprous xanthate to be the final stabilizing structure. Despite that, the changes of chemical structure did not induce the rapid leaching of copper from the copper xanthate complex.     

Effect of different types of elemental sulfur on bioleaching of heavy metals from contaminated sediments

The application of two different types of elemental sulfur (S0) was studied to evaluate the efficiency on bioleaching of heavy metals from contaminated sediments. Bioleaching tests were performed in suspension and in the solid-bed with a heavy metal contaminated sediment using commercial sulfur powder (technical sulfur) or a microbially produced sulfur waste (biological sulfur) as substrate for the indigenous sulfur-oxidizing bacteria and thus as acid source. Generally, using biological sulfur during suspension leaching yielded in considerably better results than technical sulfur. The equilibrium in acidification, sulfur oxidation and metal solubilization was reached already after 10-14 d of leaching depending upon the amount of sulfur added. The metal removal after 28 d of leaching was higher when biological sulfur was used. The biological sulfur added was oxidized with high rate, and no residual S0 was detectable in the sediment samples after leaching. The observed effects are attributable to the hydrophilic properties of the biologically produced sulfur particles resulting in an increased bioavailability for the Acidithiobacilli. In column experiments only poor effects on the kinetics of the leaching parameters were observed replacing technical sulfur by biological sulfur, and the overall metal removal was almost the same for both types of S0. Therefore, under the conditions of solid-bed leaching the rate of sulfur oxidation and metal solubilization is more strongly affected by transport phenomena than by microbial conversion processes attributed to different physicochemical properties of the sulfur sources. The results indicate that the application of biological sulfur provides a suitable means for improving the efficiency of suspension leaching treatments by shortening the leaching time. Solid-bed leaching treatments may benefit from the reuse of biological sulfur by reducing the costs for material and operating.     

生物法和化学法回收制革污泥中铬的对比研究

研究了嗜酸性硫杆菌(Thiobacillus)生物沥滤法和1:1硫酸化学沥滤法分离回收制革污泥中的铬.比较了嗜酸性硫杆菌生物沥滤法和化学沥滤法回收制革污泥铬过程中pH、氧化还原电位(ORP)、沉降比(SV)以及铬的沥滤率的变化.试验结果表明,pH是影响制革污泥中铬的沥滤率的关键因素.生物沥滤法在使污泥pH大幅度降低的同时,能很好地改善污泥的沉降性能,对铬的沥滤效果好于化学沥滤法.     

Environmental assessment of different advanced oxidation processes applied to a bleaching Kraft mill effluent

Basic research on remediation of polluted sediment by leaching has, to date, been carried out exclusively with suspended material. For economic reasons, only solid-bed leaching is applicable to large-scale processes. Abiotic and microbial solid-bed leaching were comparatively studied in a percolator system using ripened and therefore permeable heavy metal polluted river sediment. In the case of abiotic leaching, sulfuric acid was supplied to the sediment by circulating water; the lower the pH of the percolating water, the higher the percolation flow, and the lower the solid-bed height was, the faster the heavy metals were solubilized. However, the pH and percolation flow are subjected to restrictions: strongly acidic conditions result in dissolution of mineral components, and the percolation flow must not exceed the bed permeability. And a high solid bed is an economic requirement. In the case of bioleaching, elemental sulfur added to the sediment was oxidized to sulfuric acid within the package which, in turn, solubilized the heavy metals. Here, the percolation flow and the solid-bed height did not affect the rate of metal solubilization. Solid-bed leaching on a larger scale will thus be much more efficient applying bioleaching with sulfur as the leaching agent than abiotic leaching with sulfuric acid.     

提高生物法分离制革污泥中铬分离效率的研究

在已确定污泥驯化最佳条件的基础上，通过改变滤材、液固分离条件，添加营养物质继续降低pH等方法，进行提高生物沥滤法分离制革污泥中铬的分离效率的研究。同时考察化学沥滤法（1∶1硫酸）在相同条件下的分离效率。试验结果表明：用相应pH值酸液（1∶1硫酸配制）淋洗，淋洗+闷洗和抽真空＋酸液淋洗等过滤方式可提高铬的分离效率。生物沥滤中当pH值下降至1.8时，分离效率即可达到94.65%，与直接用蒸馏水淋洗相比要高得多。化学沥滤中当pH值下降到1时，分离效果可达96.7%，沥滤污泥中剩余铬含量可达到制革污泥农用标准。     

pH对污水污泥中污染物浸出的影响

研究pH对污泥中污染物浸出的影响可以为投海过程中海洋水体酸碱性变化对污泥中污染物浸出的影响及其变化规律提供理论依据。为了得出不同pH值对污泥中污染物浸出的影响，采用CEN/TS 14429：2005浸出实验对上海5个污水处理厂脱水污泥中重金属、溶解性有机碳、溶解性硫化物和主要离子的浸出情况进行了研究，同时分别以超纯水和海水为浸提剂研究在相应pH范围内盐度对上述指标浸出的影响。结果表明，Zn、Cd、Pb和As在酸性和碱性条件下浸出量较高，在中性或接近中性条件下浸出量则最低，且海水中Zn和Cd的浸出量比超纯水中高；Cu在碱性条件下的浸出量明显比酸性条件高；在所研究的pH范围内，5个污泥样品中溶解性有机碳的浸出量均随pH的升高而增高；仅酸挥发性硫含量最高的S5在海水中有较明显的溶解性硫化物浸出；部分污泥样品中的氮在酸性纯水中有较高的浸出量，海水中浸出量较少；而无论海水或纯水中，磷在强酸和强碱条件下均有明显浸出。     

Influence of initial pH on bioleaching of heavy metals from contaminated soil employing indigenous Acidithiobacillus thiooxidans

Bioleaching of heavy metals from contaminated soil was carried out employing indigenous sulfur oxidizing bacterium Acidithiobacillus thiooxidans. Experiments were carried out to assess the influence of initial pH of the system on bioleaching of chromium, zinc, copper, lead and cadmium from metal contaminated soil. pH at the end of four weeks of bioleaching at different initial pH of 3-7 was between 0.9 and 1.3, ORP between 567 and 617mV and sulfate production was in the range of 6090-8418mgl(-1). Chromium, zinc, copper, lead and cadmium solubilization ranged from "59% to 98%" at different initial pH. A. thiooxidans was not affected by the increasing pH of the bioleaching system towards neutral and it was able to utilize elemental sulfur. The results of the present study are encouraging to develop the bioleaching process for decontamination of heavy metal contaminated soil.     

The importance of the short-term leaching dynamics of wood preservatives

The potential environmental impacts from the use of treated timber in aquatic areas is under scrutiny as a result of environmental legislation and reports of the deleterious environmental effects around treated structures. In this study leaching experiments of up to 3 weeks duration were conducted on two species of chromated copper arsenate treated timber, dried for different periods of time. Increased drying time significantly reduced leaching of Cr and As. The addition of a synthetic humic acid increased leaching of Cu and As, but reduced leaching of Cr. Putative risk assessments conducted using short-term copper leaching data suggested protocol design may influence decisions made regarding the environmental acceptability of such preservatives.