氧化亚铁硫杆菌菌液脱除SO_2的实验研究

对比了酸性水溶液、酸性Fe3+溶液、含Fe3+的氧化亚铁硫杆菌菌液的SO2脱除效果,分析了氧化亚铁硫杆菌在SO2脱除过程中的主要作用。结果表明:(1)在实验的进气SO2浓度范围内,酸性水溶液对SO2的吸收仅为物理吸收,反应进行到60min时,SO2脱除率均降至15%以下,溶液不再具有SO2脱除能力。(2)对酸性水溶液、酸性Fe3+溶液和含Fe3+的氧化亚铁硫杆菌菌液3种吸收液而言,在实验的进气SO2浓度范围内,进气SO2浓度越高,SO2脱除率越低;Fe3+初始质量浓度为4.44g/L时,SO2脱除效果较好。(3)氧化亚铁硫杆菌在SO2脱除过程中,直接氧化作用不明显,其主要作用是将Fe2+氧化为Fe3+,维持溶液中Fe3+的浓度,这种间接氧化的作用对SO2的有效脱除非常重要。     

氧化亚铁硫杆菌的筛选、生长特性及其橡胶再生研究

从大西洋底死火山口土壤中筛选出一株硫杆菌,经16S rDNA鉴定为氧化亚铁硫杆菌。研究了初始底物Fe2+浓度,初始pH,接种量对其生长的影响,确定了其最佳的生长的条件:在30℃、170 r/min条件下,最适底物Fe2+浓度为9 g/L,最佳初始pH为2.5,最适接种量为10%(体积分数)。探讨了氧化亚铁硫杆菌对天然硫化橡胶的脱硫再生,橡胶的SEM分析、FTIR图谱及EDS图谱研究表明氧化亚铁硫杆菌对硫化胶粉的硫交联键有断裂或转化作用,脱硫率达52.6%,氧化亚铁硫杆菌对天然橡胶具有一定的再生作用。     

氧化亚铁硫杆菌对亚铁离子的氧化及其动力学研究

采用9K培养基研究了氧化亚铁硫杆菌氧化Fe^2＋过程中,pH和氧化还原电位的变化规律,并对Fe^2＋的氧化过程进行动力学分析,确定了其反应级数及反应速率常数。结果表明,（1）在温度为30℃,摇床转速为150r／min的条件下,氧化亚铁硫杆菌的最佳接种量为10．0％;（2）Fe^2＋初始质量浓度在11．39～21．72g／L时,随着浓度的增大,Fe^2＋达到100％转化率需要的时间增加;（3）氧化亚铁硫杆菌对Fe^2＋的氧化可近似看作一级反应,反应速率常数为0．0527～0．0788h。     

微生物代谢与Fe3+催化氧化脱除烟气中SO2的研究

利用自制的鼓泡反应器,进行了含氧化亚铁硫杆菌的酸性铁溶液脱除烟气中SO2的实验研究.结果表明,细菌直接脱硫的效果较差;Fe3 在脱硫实验过程中既有催化作用,又有氧化作用;细菌主要起氧化Fe2 为Fe3 的作用,再通过Fe3 脱硫.Fe3 存在一个最佳质量浓度,在7～8 g/L左右.当初始Fe3 质量浓度为7.37 g/L时,脱硫10 h,其效率仍高达80%.     

生物滴滤塔脱除污泥干化尾气中的SO2

以市政污泥干化尾气中的主要含硫物质二氧化硫(SO2)为处理对象,从市政污泥中筛选出高效脱硫菌——嗜酸性氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans,A.f),搭建了实验室规模的生物滴滤塔,考察了进气质量浓度、气体停留时间、营养液喷淋密度和营养液中Fe2+浓度对生物滴滤塔脱除SO2的影响....     

低品位电镀污泥对氧化亚铁硫杆菌活性的影响

以氧化亚铁硫杆菌（Thiobacillus ferroxidans,以下简称T.f菌）和低品位电镀污泥（干污泥中主要重金属组分低于3%的电镀污泥,以下简称污泥）为主要实验材料,研究了不同污泥浓度、初始pH对T.f菌Fe2＋氧化速率的影响。将实验组中T.f菌重新接种于新鲜9 K液体培养基,以考察T.f菌经实验处理后对新鲜9 K液体培养基中Fe2＋的氧化能力,结果表明,低品位电镀污泥对T.f菌Fe2＋氧化速率具有显著抑制作用,2.5 g/L的污泥浓度即可使T.f菌Fe2＋氧化速率由23.86 mg/（mL·h）降低至10.72 mg/（mL·h）;调节溶液初始pH,可有限改善T.f菌在低污泥浓度条件下的Fe2＋氧化速率,但在较高污泥浓度时,对其Fe2＋氧化速率无促进作用。     

低分子量有机酸对氧化亚铁硫杆菌影响

氧化哑铁硫杆菌生物淋滤修复重金属污染土壤研究报道很少,因为该菌对低分子量有机酸敏感.研究 6 种低分子量有机酸(甲酸、乙酸、丙酸、草酸、苹果酸和柠檬酸)对嗜酸性氧化哑铁硫杆菌 R2 氧化 Fe2 的影响,且利用高效液相色谱法测定沈阳冶炼厂和张士灌区重金属污染土壤中低分子量有机酸的浓度.结果表明,6 种有机酸对 R2 氧化能力均具有抑制作用,且抑制顺序为:甲酸乙酸丙酸草酸苹果酸柠檬酸.其中 R2 对甲酸最敏感,甲酸浓度为0.064 mmol/L时,抑制率达到 60%;浓度为 0.254 mmol/L时,R2 氧化Fe2 的能力完全被抑制.液相色谱分析可知,冶炼厂和张士灌区土壤中有机酸的浓度很低,其中草酸含量最高,分别为 0.04和 0.149 mmol/L.尽管氧化亚铁硫杆菌对低分子量有机酸很敏感,但是试验土壤中低分子量有机酸的浓度远远低于硫杆菌的耐受限度.因此,分离菌株 R2 有望应用于重金属污染土壤的修复.     

富里酸和Ca2+共存对嗜酸性氧化亚铁硫杆菌介导生成次生高铁矿物的影响

为揭示富里酸和Ca²⁺共存对嗜酸性氧化亚铁硫杆菌(Acidithiobacillus ferrooxidans)氧化酸性矿山废水(AMD)中的Fe²⁺和形成次生高铁矿物的影响,分析了pH、Fe²⁺氧化率、铁沉淀率以及次生高铁矿物矿相、基团等相关指标。结果表明,Ca²⁺确实具有提高嗜酸性氧化亚铁硫杆菌氧化Fe²⁺的能力。低质量浓度(0.2 g/L)的富里酸对嗜酸性氧化亚铁硫杆菌活性的提高具有促进作用,高质量浓度(0.4 g/L)的富里酸具有抑制作用,而增加Ca²⁺反过来能够减弱高浓度富里酸对嗜酸性氧化亚铁硫杆菌的抑制作用。对形成的次生高铁矿物进行X射线衍射(XRD)和傅立叶红外光谱(FTIR)分析,结果表明高浓度富里酸促进了另一次生高铁矿物草黄铁矾的生成。     

载体对氧化亚铁硫杆菌氧化活性的影响及生物量分析

载体的选择对氧化亚铁硫杆菌的固定化至关重要,选择活性炭、煤矸石、陶粒和沸石4种载体,考察这4种载体在不同添加量下对氧化亚铁硫杆菌氧化活性的影响,并分析载体表面附着的生物量.结果表明,这4种材料均可作为细菌固定化培养的载体材料.在载体添加量为25～75 g/L条件下,载体对细菌生长过程中Fe2 浓度变化影响最大,随载体添加量的增加,Fe2 氧化速率增加,而对pH变化和Eh变化无明显影响.单位重量的活性炭、陶粒和沸石的生物量高于单位重量煤矸石的,但随载体添加量的增加,其生物量减小;对煤矸石,随载体添加量的增加,其生物量增加.     

气田高浓度含硫废水的化学氧化处理

采用亚硫酸钠(Na2SO3)氧化法对气田高含硫废水进行了实验研究。考察了硫化物初始浓度、Na2SO3/Na2S(摩尔比)、初始pH值和反应时间对Na2SO3氧化去除硫化物效果的影响,进行了对氧化产物的元素分析。结果表明,在Na2SO3/Na2S(摩尔比)为0.7、初始pH值为5和反应时间为5 min时,硫化物从1 100 mg/L降至1.80 mg/L,去除率高达99.84%,达到了气田回注水水质标准。元素分析发现,氧化产物中C、N、S、H和O元素的含量分别为0.11%、0.06%、98.73%、0.90%和1.10%,且其产率达到90.59%。     

Essential interactions between Thiobacillus ferrooxidans and heterotrophic microorganisms during a wastewater sludge bioleaching process

The stimulating effect of heterotrophic microorganisms was investigated on the growth and on the ferrous iron oxidation of Thiobacillus ferrooxidans in synthetic media and in wastewater sludge. The addition of a sediment. Rhodotorula rubra isolate or a strain of T. acidophilus on two-layer agarose-gelled medium doubled the plating efficiency of T. ferrooxidans. In liquid cultures, R. rubra had a slight but significant effect on the growth rate of T. ferrooxidans. Moreover, the yeast allowed a faster initiation of the ferrous iron oxidation and acidification by T. ferrooxidans. In the bioleaching process, the co-culture of T. ferrooxidans with R. rubra or with the indigenous microbial assemblage from sludge was shown to be essential since the pure culture of T. ferrooxidans failed to oxidize ferrous iron and to acidify wastewater sludge. These results emphasize the importance of active heterotrophic microorganisms in the metal bioleaching activity of T. ferrooxidans in sludge.     

Hydrogen sulfide gas treatment by a chemical-biological process: chemical absorption and biological oxidation steps

In order to remove high concentrations of hydrogen sulfide (H2S) gas from anaerobic wastewater treatments in livestock farming, a novel process was evaluated for H2S gas abatement involving the combination of chemical absorption and biological oxidation processes. In this study, the extensive experiments evaluating the removal efficiency, capacity, and removal characteristics of H2S gas by the chemical absorption reactor were conducted in a continuous operation. In addition, the effects of initial Fe2+ concentrations, pH, and glucose concentrations on Fe2+ oxidation by Thiobacillus ferrooxidans CP9 were also examined. The results showed that the chemical process exhibited high removal efficiencies with H2S concentrations up to 300 ppm, and nearly no acclimation time was required. The limitation of mass-transfer was verified as the rate-determining step in the chemical reaction through model validation. The Fe2+ production rate was clearly affected by the inlet gas concentration as well as flow rate and a prediction equation of ferrous production was established. The optimal operating conditions for the biological oxidation process were below pH 2.3 and 35 degrees C in which more than 90% Fe3+ formation ratio was achieved. Interestingly, the optimal glucose concentration in the medium was 0.1%, which favored Fe2+ oxidation and the growth of T. ferrooxidans CP9.     

Persulfate oxidation for in situ remediation of TCE. I. Activated by ferrous ion with and without a persulfate-thiosulfate redox couple

The objective of the laboratory study is to examine the conditions under which transition metal ions (e.g., ferrous ion, Fe2+) could activate the persulfate anion (S2O8(2)-) to produce a powerful oxidant known as the sulfate free radical (SO4-*) with a standard redox potential of 2.6 V. The SO4-* is capable of destroying groundwater contaminants in situ such as trichloroethylene (TCE). Experiments using Fe2+ as an activator under various molar ratios of S2O8(2)-/Fe2+/TCE in an aqueous system indicated that partial TCE degradation occurred almost instantaneously and then the reaction stalled. Either destruction of SO4-* in the presence of excess Fe2+ or the rapid conversion of all Fe2+ to Fe3+ limited the ultimate oxidizing capability of the system. Sequential addition of Fe2+ in small increments resulted in an increased TCE removal efficiency. Therefore, it appeared that Fe2+ played an important role in generating SO4-*. An observation of oxidation-reduction potential (ORP) variations revealed that the addition of sodium thiosulfate (Na2S2O3) to the ferrous ion activated persulfate system could significantly decrease the strong oxidizing conditions. It was hypothesized that the thiosulfate induced reducing conditions might convert Fe3+ to a lower valence state of Fe2+, making the Fe2+ available to activate persulfate decomposition. The sequential addition of thiosulfate (S2O3(2)-), after the initial stalling of ferrous ion activated persulfate oxidation of TCE, resulted in an improvement in TCE removal. The ferrous ion activated persulfate-thiosulfate redox couple resulted in fairly complete TCE degradation in aqueous systems in a short time frame. In soil slurry systems, TCE degradation was slower in comparison to aqueous systems.     

Microbiological and chemical characteristics of an acidic stream draining a disused copper mine

Water samples draining a disused copper mine (Parys Mountain) in Anglesey, North Wales, were analysed for distribution of acidophilic bacteria (iron oxidising and heterotrophic) and for changes in physicochemical composition along the length of the drainage stream. Ten samples were taken at regular distance intervals along a 1 km stretch from the source of the acid mine drainage. The stream remained highly acidic (pH < 2.8) although a slight decrease (0.6 pH unit) in acidity with distance from source was observed. Concentrations of most metals measured decreased with distance along the length of the stream, although some showed a gradual increase and others peaked at c. 200 m from source. Most dissolved iron was in the ferrous form in the upper reaches of the stream, but ferric iron became increasingly dominant downstream as a result of microbial oxidation. Although concentrations of nutrients such as nitrogen and phosphorus were low in the acid mine drainage, they were not limiting rates of bacterial iron oxidation, which appeared to be limited more by temperature. The iron oxidising bacteria Thiobacillus ferrooxidans and Leptospirillum ferrooxidans were both isolated from all sampling sites, although their relative abundances varied; L. ferrooxidans accounted for 57% of all iron oxidising isolates. Numbers of iron oxidising bacteria decreased with distance from drainage source, in contrast to those of acidophilic heterotrophic bacteria which increased. The diversity of heterotrophic isolates also increased with distance. The relationship between the chemistry and microbiology of the stream is discussed.     

Hybrid process for heavy metal removal from wastewater sludge.

Bioleaching processes have been demonstrated to be effective technologies in removing heavy metals from wastewater sludge, but long hydraulic retention times are typically required to operate these bioprocesses. A hybrid process (coupling biological and chemical processes) has been explored in laboratory pilot-scale experiments for heavy metals (cadmium [Cd], copper [Cu], chromium [Cr], and zinc [Zn]) removal from three types of sludge (primary sludge, secondary activated sludge, and a mixture of primary and secondary sludge). The hybrid process consisted of producing a concentrate ferric ion solution followed by chemical treatment of sludges. Ferric iron solution was produced biologically via oxidation of ferrous iron by A. ferrooxidans in a continuous-flow stirred tank (5.2 L) reactor (CSTR). Wastewater sludge filtrate (WSF) containing nutrients (phosphorus and nitrogen) has been used as culture media to support the growth and activity of indigenous iron-oxidizing bacteria. Results showed that total organic carbon (TOC) concentrations of the culture media in excess of 235 mg/L were found to be inhibitory to bacterial growth. The oxidation rate increased as ferrous iron concentrations ranged from 10 to 40 g Fe2+/L. The percentage of ferrous iron (Fe2+) oxidized to ferric iron (Fe3+) increased as the hydraulic retention time (HRT) increased from 12 to 48 h. Successful and complete Fe2+ oxidation was recorded at a HRT of 48 h using 10 g Fe2+/L. Subsequently, ferric ion solution produced by A. ferrooxidans in sludge filtrate was used to solubilize heavy metals contained in wastewater sludge. The best solubilization was obtained with a mixture of primary and secondary sludge, demonstrating a removal efficiency of 63, 71, 49, and 80% for Cd, Cu, Cr, and Zn, respectively.     

Effects of sulfur dioxide and nitric oxide on mercury oxidation and reduction under homogeneous conditions

This paper is particularly related to elemental mercury (Hg0) oxidation and divalent mercury (Hg2+) reduction under simulated flue gas conditions in the presence of nitric oxide (NO) and sulfur dioxide (SO2). As a powerful oxidant and chlorinating reagent, Cl2 has the potential for Hg oxidation. However, the detailed mechanism for the interactions, especially among chlorine (Cl)-containing species, SO2, NO, as well as H2O, remains ambiguous. Research described in this paper therefore focused on the impacts of SO2 and NO on Hg0 oxidation and Hg2+ reduction with the intent of unraveling unrecognized interactions among Cl species, SO2, and NO most importantly in the presence of H2O. The experimental results demonstrated that SO2 and NO had pronounced inhibitory effects on Hg0 oxidation at high temperatures when H2O was also present in the gas blend. Such a demonstration was further confirmed by the reduction of Hg2+ back into its elemental form. Data revealed that SO2 and NO were capable of promoting homogeneous reduction of Hg2+ to Hg0 with H2O being present. However, the above inhibition or promotion disappeared under homogeneous conditions when H2O was removed from the gas blend.     

Persulfate oxidation for in situ remediation of TCE. II. Activated by chelated ferrous ion

In situ chemical oxidation (ISCO) is a technique used to remediate contaminated soil and groundwater systems. It has been postulated that sodium persulfate (Na2S2O8) can be activated by transition metal ions such as ferrous ion (Fe2+) to produce a powerful oxidant known as the sulfate free radical (SO4-*) with a redox potential of 2.6 V, which can potentially destroy organic contaminants. In this laboratory study persulfate oxidation of dissolved trichloroethylene (TCE) was investigated in aqueous and soil slurry systems under a variety of experimental conditions. A chelating agent (i.e., citric acid) was used in attempt to manipulate the quantity of ferrous ion in solution by providing an appropriate chelate/Fe2+ molar ratio. In an aqueous system a chelate/Fe2+ molar ratio of 1/5 (e.g., S2O8(2)-/chelate/Fe2+/TCE ratio of 20/2/10/1) was found to be the lowest acceptable ratio to maintain sufficient quantities of Fe2+ activator in solution resulting in nearly complete TCE destruction after only 20 min. The availability of Fe2+ appeared to be controlled by adjusting the molar ratio of chelate/Fe2+. In general, high levels of chelated ferrous ion concentrations resulted in faster TCE degradation and more persulfate decomposition. However, if initial ferrous ion contents are relatively low, sufficient quantities of chelate must be provided to ensure the chelation of a greater percentage of the limited ferrous ion present. Citric acid chelated ferrous ion appeared effective for TCE degradation within soil slurries but required longer reaction times. Additionally, the use of citric acid without the addition of supplemental Fe2+ in soil slurries, where the citric acid apparently extracted native metals from the soil, appeared to be somewhat effective at enhancing persulfate oxidation of TCE over extended reaction times. A comparison of different chelating agents revealed that citric acid was the most effective.     

接种物对厌氧同步脱硫反硝化特性的影响实验研究

分别以厌氧污泥、脱氮硫杆菌菌悬液和厌氧污泥并添加脱氮硫杆菌菌悬液为接种物,以硫化物和硝酸盐为进水基质,考察不同接种物条件下,各反应器的硫化物氧化特性、反硝化特性、生化反应机理及微生物特性。结果表明,在无菌条件下,硫化物不能被硝酸盐化学氧化。接种脱氮硫杆菌菌悬液的2#反应器的硫氧化速率为1.98 g S/(m3.h),停留24 h硫化物的去除率高达97%,脱硫能力最强,该接种条件下以硝酸盐氧化硫化物为主反应,优势菌为杆菌,进水的NO3--N/S应控制在0.4以下,可以实现高效生物脱硫。接种厌氧污泥的1#和3#反应器的脱氮效果比2#反应器好,停留时间为24 h时,硝酸盐的平均去除率为96%。单独接种厌氧污泥的1#反应器的硫氧化速率为1.78 g S/(m3.h),其优势菌为球菌,该接种条件下以硝酸盐氧化硫化物和硝酸盐氧化单质硫为主反应,进水的NO3--N/S应控制在0.8左右。以厌氧污泥联合脱氮硫杆菌为接种物时,硫氧化速率为1.71 g S/(m3.h),反应器以硝酸盐氧化硫化物、硝酸盐氧化单质硫以及异养反硝化为主反应,驯化后优势菌为球形、卵圆形和短杆状,应控制进水NO3--N/S为1.2,可以实现同步脱硫反硝化,该工艺既可以用于含硫废水的处理,也可以用于C/N低的硝酸盐废水的处理。     

Bacterial leaching of metals from sewage sludge by indigenous iron-oxidizing bacteria

Bioleaching of metals can be achieved in sewage sludge using Thiobacillus ferrooxidans, which obtains its energy requirements from the oxidation of added ferrous iron. The purpose of this study was to verify the presence of indigenous T. ferroxidans and to evaluate their adaptive capacity and leaching potential. Nineteen sludges (primary, secondary, aerobically and anaerobically digested, oxidation pond) were tested and all of them contained indigenous iron-oxidizing bacteria. The acclimation of these organisms by successive transfers allowed a rise of sludge redox potential over 450 mV and a decrease of sludge pH between 3.8 and 2.2 over a 10-day incubation period. The metal solubilization efficiencies were Cd: 55-98%, Cr: 0-32%, Cu: 39-94%, Mn: 71-98%, Ni: 37-98%, Pb: 0-31% and Zn: 66-98%, were reached with these indigenous strains. The results obtained show that the metal bioleaching may be easily realized by direct acclimation of sludge microflora.