基于生物阴极MFC的PRB中试系统处理AMD研究

为研究基于SRB生物阴极微生物电池(MFC)的固定化硫酸盐还原菌可渗透反应墙(PRB)对提高PRB处理酸性矿井废水(AMD)效果的影响,构建了中试系统,考察了进水不同p H值、重金属离子浓度及不同HRT对系统处理AMD效果的影响。结果表明:(1)MFC区有很好的调节p H功能,进水p H=3,仍能调节PRB生化反应区进水及系统出水稳定在6.5左右。(2)重金属离子的去除以MFC区为主,系统最终出水重金属离子去除率在95%左右;调节HRT=4~2 d,Fe~(2+),Cu~(2+),Zn~(2+),Ni~(2+)去除速率750~1 500 mg/(m~3·h),而Mn~(2+)去除速率略低为600~1 000 mg/(m~3·h)。(3)硫酸根的去除速率随碳源减少呈下降趋势;MFC外电压随碳源以及菌量的变化而显著变化。     

PRB处理酸性矿山废水的地球化学反应模拟研究

随着工业的迅速发展，矿产资源的需求也随之增加，采矿过程中产生的酸性矿山废水(Acid Mine Drainage, AMD)对周围环境具有严重危害性，可渗透反应墙(Permeable Reactive Barrier, PRB)通过下放置反应材料，利用自然水力梯度拦截污染羽流，该技术已成为有效处理AMD的手段之一。为研究PRB内化学反应堵塞对其处理效果的影响，搭建了规模为60 cm×15 cm×20 cm的箱体装置，模拟石灰石PRB处理AMD的过程；基于箱体实验得到的数据，并利用化学反应输运模型理论开发了一种新的地球化学算法，来描述PRB处理AMD过程中可能会发生的化学反应，最后通过MODFLOW和RT3D的耦合模拟并预测PRB有效处理污染物质的最大寿命。结果表明：(1)有效地模拟出了PRB中石灰石的酸性中和能力及其对酸性废水中总铁、Al³⁺的去除效果，并且很好地反映出PRB系统的化学堵塞过程；(2)模拟结果与实测值吻合程度较好。进口区域、中间区域以及出口区域3个不同位置处出水的pH实测值与预测值的最大误差分别为0.38、0.30和0.29,总铁质量浓度实测值与预...     

不同环境条件下的煤基胶体稳定性

为了揭示不同环境条件下煤基胶体的稳定性,实验采集辽宁省阜新市五龙煤矿选矿厂煤山底层煤粉,并用离心法提取胶体,研究pH值（pH=4~9）和电解质（Na+,Ca2+,Al3+,Mg2+,Cu2+和Zn2+）对胶体稳定性的影响,并对不同条件下煤基胶体悬液体系ζ电位进行测定。研究结果表明,煤基胶体稳定性随pH值的增加而增加,随着阳离子价数的升高而降低,同价态非重金属离子对其影响相似,同价态重金属离子比非重金属离子更易导致体系趋向不稳定状态;体系ζ电位绝对值随pH值的升高而增大,随阳离子价数的升高而降低,重金属离子<非重金属离子;不同pH值条件下的CFC值和ζ电位具有显著负相关性,且均达到0.01水平,Na+,Ca2+,Mg2+和Al3+存在时体系CFC值和ζ电位具有显著负相关性,且均达到0.01水平,Cu2+和Zn2+存在时体系CFC值和ζ电位不存在显著相关性。     

N263萃取分离锌铁及其热力学研究

研究了用N263从氯化物体系中萃取Zn2+、Fe2+和Fe3+,考察了振荡时间、萃取剂浓度、改性剂浓度、相比（O/A）、盐酸浓度对Zn2+、Fe2+和Fe3+萃取率的影响。结果表明,在有机相组成为20% N263+20%正己醇+60% 260#溶剂油、相比O/A=1 GA6FA 1、振荡时间5 min和25℃条件下,Zn2+、Fe2+和Fe3+的单级萃取率分别为90.97%、0.79%和75.85%,分离系数β_Zn2+/Fe2+和β_Zn2+/Fe3+分别为1 260和3.21。经过2级逆流萃取,水相中Zn2+浓度从9.61 g/L降至0.36 g/L,负载有机相采用0.5 mol/L H₂SO₄反萃,Zn2+的反萃率为41.86%,Fe3+的反萃率大于97%。N263萃取金属离子的机理是阴离子交换反应,计算了萃取反应相关的热力学函数值,结果表明,N263萃取Zn2+为放热反应,Fe3+的萃取反应为吸热反应,常温下Zn2+和Fe3+的萃取反应均可自发进行。      

铁屑强化麦饭石修复地下水中阴离子试验研究

针对地下水中阴离子Cr(Ⅵ)、NO3-难以利用一种可渗透反应墙(PRB)活性材料有效修复的问题,构建铁屑强化麦饭石PRB修复系统去除地下水中Cr(Ⅵ)和NO3-的试验模型。结果表明,铁屑强化麦饭石2#(麦饭石与铁屑按1∶2分层)和3#(麦饭石与铁屑按1∶2混合)柱对Cr(Ⅵ)和NO3-的去除率较1#(麦饭石)柱提高6~8倍,3#柱去除效果最好且稳定,对Cr(Ⅵ)和NO3-的平均去除率分别为97.7%和94.09%,出水质量浓度分别小于0.23 mg/L、1.18 mg/L。由此可见,铁屑强化麦饭石PRB系统修复地下水中Cr(Ⅵ)和NO3-污染物是可行和有效的。     

纳米Fe_3O_4生物麦饭石颗粒制备最优配比试验研究

针对煤矿酸性废水(AMD)中硫酸盐含量高、pH值较低,且含有毒性极强的Cr6+,处理难度大,成本高昂等特点,基于微生物固定化技术,采用纳米Fe_3O_4材料协同硫酸盐还原菌及麦饭石,制备一种纳米Fe_3O_4生物麦饭石颗粒用于处理AMD。通过开展单因素试验及正交试验以确定颗粒各基质成分的最优配比。结果表明,当纳米Fe_3O_4投加质量分数为3%,硫酸盐还原菌为30%,麦饭石为20%时,废水中SO42-去除率为85.32%,Cr6+去除率为97.45%,出水pH值为7.32,制备的纳米Fe_3O_4生物麦饭石颗粒处理AMD效果最佳。     

含铀废水中镉的处理

研究了含铀废水中镉的处理方法.采用了矿渣水泥作为吸附剂,对废水中镉进行吸附实验,实验结果表明,矿渣水泥作为吸附剂,在溶液pH为3～12,镉的浓度为10 mg/L,吸附剂用量为处理水量的0.1％时,10 min即可达到吸附最大值,除去98.5％以上的镉.溶液中含有Fe3+,UO22+,Cu2,Zn2等离子时,吸附顺序为Cu2+ ＞UO22+ ＞Fe3+ ＞Zn2+ ＞Cd2+,共存的离子对镉的吸附率影响很大,可采用分段吸附,提高对镉的吸附率.     

矿井水井下原位处理的PRB活性材料组合修复能力研究

针对矿井水地面处理的成本高和占地面积大等问题,提出矿井水井下处理与PRB修复相结合的原位处理方法,通过构建1号（无烟煤和钢渣）、2号（无烟煤和石英砂）、3号（无烟煤和沸石）、4号（无烟煤和钢渣、石英砂、沸石）PRB活性材料柱的动态实验,处理含有COD,NH4-N,PO4-P,Mn 2+,SS污染物的矿井水,研究PRB井下原位处理方法的可行性和有效性。实验结果表明：1~4号柱由于不同的组合材料而对COD,NH4-N,PO4-P,Mn 2+,SS有不同的最好去除率,其中4号柱对COD,NH4-N,PO4-P,Mn 2+,SS的平均去除率分别为59.9%,68.7%,77.9%,80.06%,88.8%,去除效果和渗透性相对较好。综合各项指标,4号柱中无烟煤、钢渣、石英砂、沸石（体积比3∶1∶1∶1）为最佳组合,适于含有机物、氮、磷和重金属离子污染矿井水的井下原位处理。     

来宾冶炼厂矾渣挥发窑低浓度SO2烟气处理

研究采用锌沸腾炉烟尘吸收来宾冶炼厂矾渣挥发窑低浓度SO2烟气。结果表明，SO2吸收率随着锌熔尘浆液pH值的降低下降较快，随着浆液总Zn量的增加先升后跌，总Zn量为90g/L时，吸收率最高。控制浆液pH值在5．0左右，单塔（一块塔板）吸收率可达65％－75％，采用3级吸收，SO2总吸收率＞985，排放尾气中SO2＜800mg/L,符合国家排放标准，吸收浆液ZnSO3加硫酸分解，放出的SO2气体送制酸系统，溶液送锌系统处理。方案在实施中。     

用天然沸石从酸性矿山废水中吸附重金属

《International Journal of Mineral Processing》2009年92卷第1/2期刊登T.Motsi等人文章,介绍用天然沸石吸附酸性矿山废水（AMD）中重金属的研究结果。为了确定天然沸石处理AMD的可用性,研究了天然沸石对AMD中重金属的吸附特性。AMD取自英国Wheal Jane矿,含有Fe3＋,Cu2＋,Mn2＋和Zn2＋分别为400,20,20和120 mg/L。通过分批试验,对每一种组分和多种组分的料液测定了吸附速率和达到平衡的吸附量。研究了pH值、竞争离子、沸石加入量、天然沸石的热改性（焙烧和微波处理）对吸附重金属的影响。通常,在40 min内即可快速达到80%的吸附率。     

膨润土复合颗粒制备工艺及其吸附性能研究

针对矿山废水中酸度、重金属离子的高成本处理问题,采用经高温焙烧的膨润土-钢渣复合颗粒对Fe2+、Mn2+、Cu2+和Zn2+进行吸附。从去除效果、碱度释放量及散失率对复合颗粒的最佳制备工艺进行研究,并用其处理模拟酸性矿山废水(AMD)。结果表明,最佳制备工艺条件为：膨润土与钢渣配比5∶5,黏结剂用量5%,焙烧温度500℃,焙烧时间60 min;当吸附剂投加量为10 g/L,吸附时间为240 min时,酸性矿山废水中Fe2+、Mn2+、Cu2+、Zn2+的去除率分别为93.21%、87.31%、100%、89.68%,出水pH值为8.31。膨润土-钢渣复合颗粒可同步降低水中酸度,去除重金属离子,且处理成本较低,值得推广应用。     

Removal of Metals and Acidity from Acid Mine Drainage Using Liquid and Dried Digested Sewage Sludge and Cattle Slurry

The metal removal and neutralization capacities of digested sewage sludges from municipal wastewater treatment plants, cattle slurry (liquid manure), and Biofert granules (dried granular anaerobic sludge) were compared under batch conditions using synthetic AMD (pH 2.8) containing high concentrations of Al, Cu, Fe, Mn, Pb, and Zn (100, 15, 270, 15, 2, and 30 mg/L, respectively). The effects of contact time and solids concentration were examined. Metal removal was variable for all materials. Contact time had a significant effect, with total removal often increasing over the experimental time interval (i.e. 30 min to 24 h). Removal efficiency (%) was generally highest for Cu, Pb, and Al, while Mn and Zn were the least removed. Cattle slurry was the best material for metal removal, with the following maximum removals at a solids concentration of 12.9 g/L: Cu >98 %, Al >98 %, Fe >60 %, Mn >18 %, Pb >96 %, and Zn >60 %. Metal removal using digested sewage sludge reached 88 % for Al, 98 % for Cu, 94 % for Pb, and 30 % for Zn. Neutralization was complete within 30 min after AMD was mixed with digested sludges or cattle slurry, with the pH reaching a maximum of 5.5 with the slurry. In contrast, neutralization by the Biofert granules only reached equilibrium after 300 min, and pH remained <4.0 except at high solids concentrations. It appears that recycled waste-derived organic materials can neutralize AMD and remove dissolved metals by adsorption and precipitation, creating a more treatable waste stream or one that could be discharged directly to surface water. Potential methods of safe disposal of metal-enriched organic materials are discussed.     

膨润土吸附剂制备工艺及吸附性影响因素研究

针对矿山废水酸度高、重金属离子处理成本过高的问题,采用膨润土、钢渣复合颗粒吸附重金属离子,从去除率、质量散失率、碱度释放量对复合颗粒制备工艺进行探讨,并研究其吸附性能影响因素,用此颗粒处理模拟酸性矿山废水(AMD)。结果表明:膨润土、钢渣配比5∶5,Na_2CO_3用量5%,焙烧粒径2 mm,500℃下焙烧60 min,吸附剂投放量10.5 g/L,反应时间240 min,振荡速率100 r/min,反应温度25℃,对Fe~(2+)、Mn~(2+)、Cu~(2+)、Zn~(2+)去除率分别为98.84%、94.93%、99.26%、96.85%,出水pH值为8.42,该复合颗粒既能去除重金属离子又能降低AMD酸度,是一种高效、环保、经济的AMD处理吸附剂。     

Removal of Metals and Acidity from Acid Mine Drainage Using Municipal Wastewater and Activated Sludge

Co-treatment of acid mine drainage (AMD) and municipal wastewater (MWW) using the activated sludge process is an innovative approach to AMD remediation that utilizes the alkalinity of MWW and the adsorptive properties of the wastewater particulates and activated sludge biomass to buffer acidity and remove metals. The capacity of these materials to treat AMD was investigated in batch mode metal removal tests using high-strength synthetic AMD (pH 2.8, Al 120–200 mg/L, Cu 18–30 mg/L, Fe 324–540 mg/L, Mn 18–30 mg/L, and Zn 36–60 mg/L). Using material from a range of MWW treatment plants, the performance of screened and settled MWW, activated sludges with mixed liquor suspended solids (MLSS) concentrations of 2.0 and 4.0 g/L, and return activated sludges with 6.0 and 7.4 g/L MLSS were compared. Similar trends were observed for the MWW and activated sludges, with removal efficiency generally decreasing in the order Al = Cu > Mn > Zn > Fe. Trends in Fe removal using settled MWW and activated sludges were highly variable, with removal <30 %. Using activated sludges, average removal efficiencies for Al, Cu, Mn, and Zn were 10–65 %, 20–60 %, 10–25 %, and 0–20 %, respectively. Sludge solids concentration was an important controlling factor in metal removal, with removal of Al, Cu, Mn, and Zn increasing significantly with solids concentration. Municipal wastewaters had greater neutralization capacities than activated sludges at high AMD loading ratios. Mixing AMD with screened MWW gave the highest removal efficiency for all metals, achieving average removal of 90–100 % for Al, Cu, and Fe, 65–100 % for Zn, and 60–75 % for Mn. These empirical findings are useful for developing process design parameters in co-treatment systems. Utilizing MWW and activated sludge to remediate AMD can potentially reduce materials and energy requirements and associated costs.     

Lime Treatment of Mine Drainage at the Sarcheshmeh Porphyry Copper Mine,Iran

Laboratory and field treatment tests were performed to evaluate the effectiveness of lime treatment for mitigation of environmental effects of acid mine drainage (AMD) at the Sarcheshmeh porphyry copper mine. AMD associated with the rock waste dumps is contaminated with Al (>36,215 μg/L), Cd (>105 μg/L), Co (>522 μg/L), Cu (>53,250 μg/L), Mn (>42,365 μg/L), Ni (>629 μg/L), and Zn (>12,470 μg/L). The concentrations of other metals (Fe, Mo, Pb, and Se) are low or below detection limits (As, Cr, and Sb). Due to the very high Al and Mn content and the low concentration of Fe, a two-stage lime treatment method was chosen for the laboratory tests. In the first stage, the AMD was treated at four pH set points: 7.5, 8.9, 9, and 10. In the second stage, after removing the sludge at pH 9, treatment was continued at pH 10 and 11. The results indicated that a two-stage treatment method was not necessary because elements such as Al, Cu, Co, and Zn were easily treated at pH 7.5, while complete removal of Cd, Mn, and Ni only required a pH of 10. Increasing pH during the treatment process only caused a slight increase in Al. Field treatment tests support the laboratory results. Lime treatment of highly contaminated AMD from dump 11, using simple low density sludge pilot scale equipment, show that contaminant metals are treatable using this method. The mean treatment efficiency for contaminant metals was 99.4% for Al, % for Cd, 99.6% for Co, 99.7% for Cu, 98.5% for Mn, 99.7% for Ni, 99% for U, and 99.5% for Zn. The optimum pH for AMD treatment by lime was in the range of 9–10. The produced sludge in the treatment process was highly enriched in the contaminant metals, especially Cu (>7.34%), Al (>4.76%), Mn (>2.94%), and Zn (>1.25%). A correlation coefficient matrix indicates that the distribution pattern of the contaminant metals between soluble and precipitated phases is consistent with the hydrochemical behavior of the metals during the lime treatment process.     

Assessment of Soil and Water Contamination at the Tab-Simco Coal Mine: A Case Study

In 1996, the Tab-Simco site, an abandoned coal mine 10 km southeast of Carbondale, Illinois, was listed as one of the most highly contaminated AMD sites in the mid-continent region. A suite of impacted soil and water samples were collected from various locations to characterize the current extent of AMD pollution, following standard U.S. EPA protocols. The mean pH of soil and water samples were found to be 2.69 and 2.07, respectively. The mean sulfur content of the soil samples was 0.5 %. The AMD-impacted soils contained high concentrations of Fe, Zn, Ni, Cr, Cu, Pb, and As. The AMD also contained high concentrations of Fe, As, Zn, Pb, Cr, Al, Cd, Cu, and Ni, as well as \({\text{SO}}_{4}^{2 - }\), all of which were significantly above their U.S. EPA permissible limits for surface water.     

Evaluation of Hydrotalcites Produced in Seawater for Remediation of Metalliferous Acid Mine Drainage and Submarine Placement

Uncontrolled release of acid mine drainage (AMD) causes widespread detrimental impacts on the receiving environment. Thus, effective treatment to neutralise AMD effluent pH and capture a suite of metals is required. In-situ hydrotalcite (HTC) precipitation is an emerging technology for AMD remediation. HTC has an inherent capacity to accommodate a range of cations and anions during in situ formation, offering a method of broad-spectrum contaminant removal. This study explored the feasibility of using seawater as an Mg source and synthetic AMD in HTC formation. The HTC was formed from a stoichiometric combination of synthetic AMD and seawater. While three initial stoichiometric M²⁺:M³⁺ ratios of 2:1, 3:1, and 4:1 were investigated, only HTC with an M²⁺:M³⁺ ratio of 2:1 was generated, as confirmed by both mineralogical and geochemical analyses. Importantly, the HTC was demonstrated to effectively remove a suite of metals present in AMD such as Cu, Zn, Al, and Mn with removal rates of between 99.97 to 99.99%. The HTC precipitate contained ≈6.6% Cu and 4.1% Zn, and thus shows the potential, if required, for future metal recovery. Since submarine placement is often used in metal mining and processing operations proximal to the coast, the stability of the HTC precipitate in seawater was also investigated. Importantly, only 0.2% of the Cu and 1.1% of the Zn within the HTC were subsequently leaching in decreasing increments into seawater over 30 days with decreasing increments after the initial seven days. This indicates robust element retention and confirms the potential of HTC for AMD remediation with direct submarine placement.

     

Zn~(2+)、Cu~(2+)对菱锌矿和石英浮选的影响及作用机理

在氧化锌矿的浮选实践中,石英大量进入浮选精矿。通过浮选试验、动电位测试和溶液化学计算的方法,考察浮选体系中的难免金属离子(Zn2+,Cu2)+对菱锌矿-石英浮选体系的影响及机理。研究结果表明,Zn2+和Cu2+在整个试验pH范围内对菱锌矿均有一定的活化作用;在没有金属离子存在时石英不可浮;Zn2+、Cu2+在pH 6~11的范围内能活化石英的浮选;Zn2+和Cu2+对石英浮选活化的pH范围与金属氢氧化物形成的pH范围有关。     

粉煤灰对煤矸石酸性重金属淋滤液的修复作用

采用批处理吸附实验和柱状淋溶模拟实验,分析粉煤灰吸附重金属、处理煤矸石酸性重金属淋滤液的效果及机理。结果表明：① 粉煤灰对Pb2+、Cu2+、Cd2+ 和Zn2+的吸附等温线符合Freundlich等温模式,吸附过程符合准二级反应动力学模型,且均在30 min内达到吸附平衡,随着pH增加,4种重金属离子吸附率逐渐增加并趋于平衡（Pb、Cu、Cd、Zn分别在pH=3.5、6.0、7.5、8.0时达到平衡）,在酸性环境下粉煤灰对4种金属离子具有较好的吸附性能;② 在重金属竞争性吸附中,共存离子的存在抑制了目标离子的吸附,其中Pb受共存离子的影响最小,粉煤灰吸附强弱顺序为Pb>Cu>Cd>Zn;③ 煤矸石柱状淋溶试验中,煤矸石淋滤液呈现较强酸性、较高重金属浓度的酸性矿山废水特征,而在粉煤灰处理中,淋滤液的pH值呈中性,重金属离子浓度显著下降,其主要机制为粉煤灰吸附、碱性中和、重金属与Fe共沉淀等。研究表明,实验用粉煤灰具有修复煤矸石酸性重金属淋滤液的潜力。