Acidithiobacillus thiooxidans浸出印刷线路板中金属的研究

印刷线路板(PCB)作为电子垃圾的主要成分,传统的处理方法环境污染严重,而且造成资源的严重浪费,因此找到无污染和可回收再利用的处理技术显得尤为重要.实验检测了利用嗜酸浸矿微生物处理印刷线路板回收其中金属的可行性,选用本实验室筛选的A.thiooxidans,对PCB中的金属进行了摇瓶浸出试验.在摇瓶培养中,10%的接种量,添加1.0 g样品时,Cu的浸出率达到了59.76%,而同期对照的H2SO4浸出试验中,其浸出率只有42.94%,对其他金属元素也有较好的效果.结果表明,利用A.thiooxidans比纯酸浸更能取得良好的效果.

嗜酸性氧化硫硫杆菌(Acidithiobacillus thiooxidans)TT03对碱性土壤的作用效果

针对前期研究中选育出的氧化硫硫杆菌TT03,为了解其对单质硫的转化作用而进行了试验。试验的结果表明,TT03与硫粉的加入,使得碱斑土壤与碱性耕作土壤的pH及性状发生改变,土壤向有利于耕作的方向发展;在碱性土壤中,培养到28d时pH下降到7.94,硫酸根含量达到187.4mg/kg,单质硫转化率达56.4%;在培养至63d时,pH下降到7.73,硫酸根含量上升到232.3mg/kg,单质硫转化率达71.4%。

氧化硫硫杆菌(Acidithiobacillus thiooxidans)TT03的生长条件研究

针对前期筛选鉴定的氧化硫硫杆菌(Acidithiobacillus thiooxidans)TT03,为进一步了解和掌握其培养方法进行了本项研究。结果表明:TT03适宜在初始pH2.0～6.0与温度25℃～35℃的范围内生长;以硫酸铵为第一氮源,也可利用尿素和硝酸盐生长;为保证稳定的培养,需要加大接种量到2.0%以上;适量的氧气供给对TT03的生长是有利的;在二氧化碳的浓度达6%以上时生长受到抑制,而在6%以下时,对TT03的生长有促进作用。

Bioleaching of low-grade copper sulfide ores by Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans

The grown conditions of Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans were investigated,and then experiments were conducted to research the bioleaching behaviors of crude ore of copper sulfide and hand-picked concentrates of chalcopyrite by Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans.The experimental results show that the bacteria grow best when the temperature is(30±1) °C and the pH value is 2.0.The bacteria concentration is 2.24×107 mL-1 in this condition.It is found that the copper extraction yield is affected by the inoculum size and the pulp density and the extraction yield increases as the inoculum size grows.The bioleaching rates reach their highest point in sulfide copper and chalcopyrite with a pulp density of 5% and 10%,respectively.Column flotation experiments of low-grade copper sulfide ores show that the bioleaching recovery reaches nearly 45% after 75 days.

Bioleaching and electrochemical properties of chalcopyrite by pure and mixed culture of Leptospirillum ferriphilum and Acidthiobacillus thiooxidans

The bioleaching of chalcopyrite was investigated using a pure and mixed culture consisting of iron-oxidizing Leptospirillum ferriphilum （L. ferriphilum） and sulfur-oxidizing Acidthiobacillus thiooxidans （.4. thiooxidans）. The electrochemical tests were conducted to investigate the bioleaching behavior of chalcopyrite by various bacteria. Bioleaching efficiency of chalcopyrite in mixed culture is higher than that in the pure culture of L.ferriphilum alone. The iron-oxidizing L.ferriphilum plays a dominant role during bioleaching of chalcopyrite in the mixed culture of L. ferriphilum and A. thiooxidans. During bioleaching, certain values of redox potential are beneficial to the decomposition of chalcopyrite. Jarosite and sulfur are observed as products of bioleaching. The addition of A. thiooxidans during leaching by L. ferriphilum can change the electrochemical control steps of leaching. The corrosion current density is substantially promoted in the culture involving bacteria, especially in the mixed culture.

Single and cooperative bioleaching of sphalerite by two kinds of bacteria——Acidithiobacillus ferriooxidans and Acidithiobacillus thiooxidans

A cooperative bioleaching(Acidithiobacillus ferriooxidans and Acidithiobacillus thiooxidans)and single bioleaching(Acidithiobacillus ferriooxidans or Acidithiobacillus thiooxidans)of sphalerite were investigated by X-ray diffractometry,energy dispersive spectrography and scanning electron microscopy.The experimental results show that the leaching rate of zinc in the mixed culture is higher than that in pure culture and the sterile control.In these processes,two kinds of bacteria perform different functions and play a cooperative role during leaching of sphalerite.The bioleaching action carried out by Acidithiobacillus ferriooxidans(A.ferriooxidans)is not directly performed through Fe2+ but Fe3+,and its role is to oxidize Fe2+ to Fe 3+ and maintain a high redox potential.Moreover,the addition of an appropriate concentration of ferric iron to the leaching systems is beneficial to zinc dissolution.In the leaching systems without Acidithiobacillus thiooxidans(A.thiooxidans),elemental sulfur layers are formed on mineral surface during the dissolution of zinc and block continuous leaching.Acidithiobacillus thiooxidans,however,eliminate the passivation and cause the bioleaching process to continue in the leaching systems.At the same time,protons from the bacterial oxidization of the elemental sulfur layers also accelerate the leaching of zinc.

Microbial leaching of marmatite by Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans

The bioleaching of marmatite in shaken flasks was studied. After leaching for 29 days, the leaching ratio of zinc was 91%. Three kinds of bacteria, mixture-based bacteria, 9K-based bacteria and sulfur-based bacteria were used in marmatite leaching, of which the mixture-based bacteria have the best leaching result while the sulfur-based bacteria have the worst. By analyzing the leaching residue using SEM and EDXA, the marmatite leaching mechanism was discussed.

Electrogenerative leaching for sphalerite-MnO_2 in the presence of Acidithiobacillus thiooxidans

A dual cell system was used to study the electrogenerative leaching sphalerite-MnO2 in the presence and absence of Acidithiobacillus thiooxidans (A. thiooxidans). The polarization of anode and cathode, and the relationship between the electric quantity (Q) and some factors, such as the dissolved rate of Zn2+ and Fe2+, and the time in the bio-electro-generating simultaneous leaching (BEGL) and electro-generating simultaneous leaching (EGL) were studied. A three-electrode system was applied to studying anodic and cathodic self-corrosion current, which was inappreciable compared with the galvanic current between sphalerite and MnO2. The results show that the dissolved Zn2+ in the presence of A. thiooxidans is nearly 43% higher than that in the absence of A. thiooxidans; the electrogenerative quantity in the former is about 150% more than that in the latter. The accumulated sulfur on the surface of sulfides produced in the electrogenerative leaching process can be oxidized in the presence of A. thiooxidans, and the ratio of biologic electric quantity reaches 27.9% in 72 h.

Investigation of mortar corrosion by an acidophilic sulfur-oxidizing microorganism A.thiooxidans

The corrosion behavior of the acidophilic sulfur-oxidizing microorganism(ASOM)Acidithiobacillusthiooxidans(A.thiooxidans)on mortar was investigated for changes of medium and mortar,as well as for weight lossand surface morphology of mortar specimens.Weight loss analysis showed that mortar weight was reduced by(15.1±2.2)%after 56 d.Morphological surface analysis of mortar specimens showed weakly structured fibrous substances with2−100μm in size.The pH variations of the mortar surface and medium indicated that biogenic sulfuric acid had beenproduced by A.thiooxidans.The results prove that A.thiooxidans accelerated concrete corrosion and caused concretefailure.

养殖池塘系统脱氮硫杆菌(Thiobacillus denitrificans)的分离、生长特性及脱氮特征研究

分别采集集约化养殖吉富罗非鱼(Oreochromis niloticus)的池塘底泥、表层水、塘边裸露土壤样品,采用脱氮硫杆菌选择培养基富集培养、分离得到3株细菌,通过菌落特征、形态学特征、生理生化检验和16S rDNA序列分析等手段,鉴定为脱氮硫杆菌(Thiobacillus denitrificans),命名为TD1、TD2和TD3。在30℃下,采用静置、厌氧培养实验研究这3株脱氮硫杆菌的生长繁殖特征、对硝酸盐氮的去除速率特征、硫酸根产生状况、亚硝酸盐产生情况、培养液pH值和氧化还原电位变化特征等方面的差异进行研究,探索养殖环境修复中应用的可能性。结果表明:在一定的时间内菌株生长速率、介质pH降低速率和氧化还原电位上升幅度均表现为TD1>TD2>TD3;菌株硝态氮脱除效率和硫酸根浓度升高速率均表现为TD1>TD2>TD3,亚硝酸盐产生情况则表现为TD1<TD2<TD3;TD1更适合异位修复,TD2更适合原位修复。

氧化亚铁硫杆菌(Thiobacillus ferrooxidans)对重金属富集植物腐蚀作用研究

为了获得重金属富集植物生物法预处理的最佳工艺条件,实现其资源化利用,以黑麦草(Lolium perenne)为材料,探究氧化亚铁硫杆菌(Thiobacillus ferrooxidans,T.f)在不同接种量和不同浓度底物添加剂(S0、Na2S2O_3、Fe SO4、Fe S和Fe0)条件下对黑麦草的腐蚀作用,通过扫描电镜进一步观察其对细胞壁的破坏情况。结果表明:氧化亚铁硫杆菌对黑麦草具有较好的腐蚀作用,各接种量(5%~15%)之间差异较小,反应第10 d,10%接种量处理组中黑麦草的纤维素降解率达40.97%,半纤维素降解率达77.49%,木质素降解率达19.33%。投加底物添加剂后,氧化亚铁硫杆菌对纤维素降解率有明显提高。总体来看,添加14 g·L^(-1)的S0对黑麦草的降解效果较好,纤维素、半纤维素及木质素的降解率分别达到81.31%、82.29%、26.02%,此条件下铀、铬、镉的浸出效率均较高。在氧化亚铁硫杆菌及底物添加剂的作用下,除Fe S、Fe0处理组外,其他各处理组的pH值均呈下降趋势,反应10 d后,pH值最低降至1.0左右,pH值的降低能有效提高半纤维素降解率,但与纤维素及木质素的降解率无明显关系。扫描电镜结果表明氧化亚铁硫杆菌对黑麦草细胞壁有较强的破坏作用。氧化亚铁硫杆菌对黑麦草具有很好的腐蚀效果,并且能充分利用底物添加剂提高黑麦草中纤维素降解率。后期需进一步考虑提高氧化亚铁硫杆菌对木质素的降解效率及黑麦草中重金属的回收率。

养殖池塘脱氮硫杆菌(Thiobacillus denitrificans)的空间分布及与相关理化因子关系研究

为了研究养殖池塘中脱氮硫杆菌的分布状况及在水体中与相关理化因子的关系,分别分层采集吉富罗非鱼(Oreochromis niloticus)精养池塘底泥样品和水样,采用最大可然数法(MPN)对底泥和水体中脱氮硫杆菌进行定量分析,同时测定分层水样理化指标值。结果表明:底泥和水体中,随着深度增加,脱氮硫杆菌数量均逐渐减少,底泥中变化为从每克干重105数量级降到102数量级,水体中为从每毫升103数量级降到102数量级;脱氮硫杆菌数量与几种理化因子间相关性分析结果表明:其与硝态氮呈正相关关系,与硫化物呈负相关关系,原因可能为硫化物和硝酸根的分布为池塘中溶氧分布必然结果,而硝酸根诱导了其细胞内同化型硝酸还原酶活性。

Pyrite Surface after Thiobacillus ferrooxidans Leaching at 30℃

In order to investigate the effect of Thiobacillusferrooxidans on the oxidation of pyrite, two parallel experiments, which employed H2SO4 solutions and acidic solutions inoculated with ThiobaciUus ferrooxidans, were designed and carried out at 30℃. The initial pH of the two solutions was adjusted to 2.5 by dropwise addition of concentrated sulphuric acid. The surfaces of pyrite before exposure to leaching solutions and after exposure to the H2SO4 solutions and acidic solutions inoculated with Thiobacillus ferrooxidans were observed by scanning electron microscopy （SEM）. There were a variety of erosion patterns by Thiobacillusferrooxidans on the bio-leached pyrite surfaces. A conclusion can be drawn that the oxidation of pyrite might have been caused by erosion of the surfaces. Attachment of the bacteria to pyrite surfaces resulted in erosion pits, leading to the oxidation of pyrite. It is possible that the direct mechanism plays the most important role in the oxidation of pyrite. The changes in iron ion concentrations of both the experimental solutions with time suggest that ThiobaciUus ferrooxidans can enhance greatly the oxidation of pyrite.

Study on bioleaching of refractory gold ore (Ⅰ)──Mechanism on bioleaching of pyrite by Thiobacillus ferrooxidans

The variation of main parameters including ion concentration, pH value, potential and biomass was examined in bioleaching pyrite. The pH value of the solution decreased obviously. Most of T.ferrooxidans adhered to the surface of pyrite. The surface properties of pyrite and leached products were determined by SEM, EDS and XRD. Pyrite was corroded selectively by T.ferrooxidans and sulfur in pyrite was leached preferentially. The primary product for bioleaching pyrite was jarosite. Based on these results, it can be found that pyrite is oxidized mainly through the direct role of T.ferrooxidans . A band model for bioleaching pyrite was built, by which the bioleaching process was explained theoretically. The model shows that the holes, which are injected into the valence band of pyrite through adhered T.ferrooxidans , result from dissolved oxygen in the solution.

萃取有机物污染黄铜矿的At.thiooxidans菌浸出

铜萃取有机物对浸矿微生物的危害日益受关注,探讨了Acidithiobacillus thiooxidans(At.thiooxidans)菌在被铜萃取有机物污染的低品位黄铜矿表面的吸附行为及其生物浸出特征。结果表明:由于萃取有机物的吸附增强了矿石表面疏水性与电负性,使At.thiooxidans细胞在受污染低品位黄铜矿表面的吸附率提高19%。然而,高细胞吸附率并不意味着高浸出率。在受污染低品位黄铜矿的生物浸出过程中,细胞生长速度降低9%,铜浸出率降低29%。CLSM以及SEM观察发现,在萃取有机物胁迫下,附着细胞的胞外多聚物(Extracellular polymeric substances,EPS)分泌受到抑制,势必影响生物膜的构建。在矿石被污染的情况下,有机膜覆盖、细胞新陈代谢受抑制、EPS分泌减少,是导致浸出率降低的主要原因。

Growth kinetics of Thiobacillus ferrooxidans in bioelectrochemical cell

Thiobacillus ferrooxidans might be the most important bacteria used in biometallurgy. The foundation way of its growth process is oxidizing ferrous in order to obtain energy needed for metabolism, but the variation of ferrous concentration and mixed potential of the culture media would have crucial effect on the bacteria growth. Based on the characteristics of Thiobacillus ferrooxidans growth and redox potential of ferric and ferrous, an electrochemical cell was designed conventionally to study growth rule and the relationship between redox potential and bacteria growth was built up, and some growth kinetics of Thiobacillus ferrooxidans were elucidated. It demonstrates that the variation of open potential of electrochemical cell Δ E shows the growth tendency of Thiobacillus ferrooxidans , at the initial growth stage, the value of Δ E increases slowly, when at logistic growth stage, it increases drastically, and the growth rate of bacteria is linear with the oxidation rate of ferrous. The bacteria growth kinetics model is proposed using Monod and Michealis-Menten equation, and the kinetics parameters are got. The consistence of the measured and the calculated results proves that it is proper to use the proposed kinetics model and the electrochemical cell method to describe the growth rule of Thiobacillus ferrooxidans .

THE DEPRESSION OF PYRITE FLOTATION BY THIOBACILLUS FERROOXIDANS

The experimental studies on the microbial flotation of a pure pyrite sample using Thiobacillus ferooxidans was conducted in the laboratory. The results indicate that Thiobacillus ferrooxidans has strong depression effect on the flotation of pyrite. Thiobacillus ferrooxidans can adsorb on the surface of pyrite in a very short time (a few min.), changing the surface from hydrophobic into hydrophilic and making the pyrite particles to lose their floatability. Therefore, Thiobacillus ferrooxidans is an effective microbial depressant of pyrite. It has also been pointed out that the depression of pyrite by Thiobacillus ferrooxidans is caused by the adsorption of the microbial colloids, but not by the oxidation effect.

Corrosion Behaviors of Steel A3 Exposed to Thiobacillus Ferrooxidans

The corrosion behaviors of steel A3 in synergistic action of Thiobacillus ferrooxidans （T.f） and electrochemically accelerated corrosion were studied by electrochemical, microbiology and surface analysis methods. The open circuit potential （Eocp） and electrochemical impedance spectroscopy （EIS） of the steel A3 electrodes were measured in leathen culture medium without and with T.f （simply called T.f solution in the following paper） in immersion electrode way at the time of the 2nd, 5th, 10th, 20th and 30th days, respectively. It was found that Eocp of the electrode for immersion in leathen culture medium shifted negatively with the immersion time while that for immersion in T.f solutions shifted negatively, then positively and finally negatively. On the 20th day, the corrosion of steel A3 for immersion in culture medium was in pitting initiation stage while that for immersion in T.f solutions was in pitting growth stage. It was found that the corrosion of steel A3 was accelerated by T.f. The morphology of corrosion product of steel A3 immersion in T.f solutions observed through scanning electron microscopy （SEM） transformed from solid globules to tabular plates and to spongy globules and plates.

New Method of Manufacturing Micro Parts Using Thiobacillus Ferrooxidans

A new method of processing and manufacturing certain parts of instruments through biological approach is studied. Knowledge of feasibility of micro-manufacturing is obtained by comparing experimental results of etching surfaces of copper, aluminium alloy, brass, steel and stainless steel using strain of Thiobacillus ferrooxidans （ T. f. ）. Our experimental results show that certain metals can be etched using T. f., the most feasible material is copper, followed by brass, etc., with stainless steel the least. The surface of the stainless steel material is nearly unchanged during surface-etching. Micro parts made of copper or brass can be satisfactorily processed with T.f. and the rate of processing on copper is about 14 μm/h. Furthermore, surface roughness and processing speed are controlled by pH value and temperature of etching liquid, in addition to swing rate of the the swing bed.

A new strain Acidithiobacillus albertensis BY-05 for bioleaching of metal sulfides ores

An acidophilic,rod-shaped Gram-negative sulfur oxidizing strain BY-05 was isolated from an acid mine drainage of copper ore in Baiyin area,Gansu Province,China.Ultrastructural studies show that the isolate has a tuft of polar flagella and possesses sulfur granules with clear membrane adhering to the cell innermembrane.Physiological study shows that this isolate grows autotrophically and aerobically by oxidizing S0and reduced inorganic sulfur compounds(SO, 2 23-SO, 2 24- S2 -and ZnS)with the optimum growth at pH 3.5-4.0 and at the temperature range of 25-30℃.The 16S rRNA gene sequence(DQ 423683)of strain BY-05 has 100%sequence similarity to that of Acidithiobacillus albertensis(DSM 14366).So it is identified and named as A. albertensis BY-05.Bioleaching experiments with this new strain show that it can play an important role in recovery of metals from chalcopyrite and sphalerite.