石灰石—石灰乳二段中和法处理酸性废水的试验研究及工业实践

乌拉嘎金矿生物氧化预处理工艺原酸性废水采用石灰乳一段中和法进行处理,系统运行成本高,达321.762万元/a,仅生石灰粉消耗的成本达206.4元/t金精矿。通过小型试验及可行性分析,确定采用石灰石—石灰乳二段中和法处理酸性废水,处理后废水达到排放标准,且沉淀量少,同时有效地降低了生产成本。详细介绍了酸性废水石灰石—石灰乳二段中和法处理试验应用过程。工业实践表明,石灰石—石灰乳二段中和法系统运行稳定,处理效果好,达到了降本增效目的。     

碳酸钡法去除有色金属冶炼厂综合废水中Ca~(2+)和SO_4~(2-)的试验研究

有色金属冶炼厂产生大量含重金属的酸性废水。目前,重金属废水处理大都采用石灰中和法,但经处理后的出水中Ca2+和SO2-4浓度偏高,不适合作工艺循环冷却水系统的补充水。因此,提出用BaCO3去除Ca2+和SO2-4。分析了BaCO3去除水中Ca2+和SO42-机理,通过动态试验,研究了不同投加剂量、反应温度、反应时间以及沉淀时间对BaCO3去除水中Ca2+和SO2-4的影响。     

MJS-1型填料吸附法脱除重金属废水中COD的研究

采用自制MJS-1型填料对重金属废水进行了吸附脱除COD的试验研究,考察了p H值、反应时间、MJS-1型填料用量、反应温度对COD脱除率的影响。结果表明:采用MJS-1型填料为吸附剂,处理水量为1 L时,进水p H值为9、停留时间为1 h、填料用量为1. 0 g/L、温度为25℃时,COD脱除率达到73. 87%,出水COD约为30 mg/L。     

钽铌冶炼厂酸性含氟废水处理试验研究

用单纯的石灰中和沉淀法处理高浓度酸性含氟废水很难达到排放标准(≤10mg·L-1)。试验采用两步中和沉淀法处理稀土冶炼产生的酸性高氟废水,即分两次投加石灰乳,并用PAM作为混凝剂。结果表明,采用该工艺处理后的出水含氟量低于5mg·L-1,重金属离子含量也可达到排放标准,同时可提高石灰的利用率和改善处理效果。     

某有色金属冶炼废水处理工程的设计

采用石灰中和沉淀法处理有色金属冶炼废水,主要流程是进水→格栅→调节池→中和反应槽→絮凝反应槽→斜板沉淀池→出水。该污水处理系统具有流程简单、技术成熟、经济实用、废水停留时间短等优点,出水达到《污水综合排放标准》(GB8978—1996)中第一、二类污染物最高允许排放浓度一级标准。     

酸性重金属废水的联合处理试验研究

采用硫化沉淀法将酸性重金属废水中的铜进行沉淀回收,处理后废水用氧化钙中和后产生的中和渣和中和液进入选矿系统。试验结果表明:采用硫化沉淀法可以回收高品位的铜,回收率较高;与自来水进行选矿试验相比,中和处理产生的中和渣和中和液进入选矿流程同样可获得良好的选矿指标,二者基本相同。该工艺可利用现有的选矿设备实现酸性重金属废水的资源化治理。     

重金属离子捕集法(DTCR)高效除砷技术研究

针对不同的废水对象,分别开展反应pH值、DTCR捕收剂、混凝剂优选等除砷研究,表明酸性含砷废水采用中和法即可使水中砷含量达国家环保要求,且水体中铁砷比值越大越有利于砷的去除。对碱性含砷废水同时进行扩大试验,砷去除率达99.86%,出水砷含量0.31 mg/L,低于国家环保污水外排要求。该研究结果对环保处理系统短流程及应急性除砷方面具有一定指导意义。     

酸性矿山废水去除重金属试验研究

矿产资源生产过程中产生大量酸性矿山废水，其酸性强、硫酸盐含量高，且重金属离子种类多，易造成环境污染。试验采用生物炭吸附—沉淀法去除酸性矿山废水中重金属离子，生物炭以玉米秸秆为原料，在600℃下热解制成，考察了其对酸性矿山废水中铜去除的影响，以及生物炭吸附剂脱附再生后的吸附能力；之后采用沉淀法去除其他重金属，处理后废水中各污染物达到GB 8978—1996 《污水综合排放标准》一级排放标准要求。     

金川公司尾矿砂浆中和酸性废水探索性试验研究

对金川公司酸性废水与尾矿砂浆以不同比例、不同方式进行探索性中和试验,结果表明,混合酸性废水与尾矿砂浆混合比例大于1.2:1时,在30min内,混合溶液的pH值即可大于6,中和后溶液的沉降速度明显增加。试验同时表明,浓缩酸性废水及加入干尾砂后,中和效果显著,澄清液中重金属污染物可达到国家《污水综合排放标准》(GB8978-1996)二级水质标准。     

某有色金属矿山酸性重金属废水治理试验研究

对某有色金属矿山酸性重金属废水采用反渗透膜技术进行了处理,对产生的浓缩液分别采用中和法、直接硫化法、一段中和硫化法、中和渣回流硫化法、铁还原硫化法进行了试验研究。其结果表明:反渗透膜技术对有色金属矿山酸性重金属废水的分离浓缩效果较好;产水调节p H值后可达标排放;浓缩液采用中和硫化法或铁还原硫化法适合废水中铜离子的回收,一段中和硫化法得到的沉渣中铜具有很高计价品位,而中和渣回流硫化法可节省石灰乳的用量,且沉渣中铜具有较好计价品位,综合优势较为突出。     

钢渣去除废水中重金属离子的研究综述

 钢渣具有比表面积大、疏松多孔且在水溶液中易水解电离出Ca2＋、Fe2＋、OH－、羟基化基团SOH等性质,能很好地去除废水中重金属离子,且效率较高。钢渣对重金属离子的去除机理包括物理吸附和化学吸附。物理吸附主要依靠钢渣与溶液中重金属离子之间的范德华力;化学吸附主要包括表面配位、阳离子交换、化学沉淀及还原作用。钢渣对重金属离子的吸附效率主要受溶液的pH值、重金属离子初始浓度、钢渣的组分及粒径等影响。目前关于钢渣吸附重金属离子的研究多是静态吸附试验,并且采用的多是人工合成的单一组分废水,与现实存在一定的差异。因此,未来需进一步开展钢渣去除重金属离子的动态去除效率及规律研究,并深入探讨其他污染物质对钢渣去除效率的影响。     

Removal of Metal Ions from Storm-Water Runoff by Low-Cost Sorbents: Batch and Column Studies

The possibility of using the sorption technology to reduce the levels of metal ions present in urban storm-water runoff was investigated in this study. Seven sorbent materials including Amberlite XAD7, chitosan, crab shell, peat, Sargassum, sawdust, and sugarcane bagasse were initially examined for removal of 11 metal ions (Na, K, Ca, Mg, Mn, Co, Ni, Cu, Zn, Cd, and Pb) from simulated storm-water runoff at different concentrations. Among these sorbents, crab shell performed well with removal efficiencies exceeding 93% for all heavy metal ions examined and thus selected for further studies. Based on scanning electron microscopy/energy-dispersive x-ray analysis, microprecipitation of metal carbonates followed by adsorption onto the surface of crab shell was identified as the major mechanism responsible for removal of heavy metal ions by crab shell. Crab shell exhibited rapid removal of meal ions with attainment of biosorption equilibrium within 20 min. A crab-shell-packed column was used to study the continuous metal retention process. The column performed very well in the removal of heavy metal ions and was able to operate up to 192 h at a flow rate of 10 mL/min before outlet concentrations of Mn and Co reached 0.3 times of their respective inlet concentrations. Other metal ions such as Pb, Zn, Ni, Cd, and Cu were only in trace levels in the final effluent until 192 h. These findings would form the basis for the future development of crab-shell-based biofilters for removal of dissolved heavy metal ions from storm-water runoff.     

钢渣吸附剂对铬和铅重金属离子的吸附特性研究

采用振荡吸附实验，研究了振荡器转速、吸附时间、钢渣投入量、溶液pH、溶液中溶质离子的初始浓度等因素对钢渣吸附Cr^3 、pb^2 的影响。结果表明，钢渣对溶液中重金属离子Cr^3 、pb^2 具有较强的吸附作用，对Cr^3 的吸附去除率一般可达99%以上，对pb^2 的吸附去除率一般可达94％以上；钢渣吸附处理Cr^3 、pb^2 的适宜投加量为：钢渣与铬的质量比为300:1，钢渣与铅的质量比为200:1；钢渣能够很好地适应废水pH和离子初始浓度的变化，对吸附去除Cr^3 、pb^2 保持较高而稳定的吸附去除率。     

静电纺丝纳米纤维膜分离富集重金属的研究进展

静电纺丝是制备纳米纤维的一种简单有效的技术,纳米纤维具有很高的比表面积,因此静电纺丝纳米纤维膜用于分离富集重金属具有很大的潜力.通过查阅文献,综述了利用静电纺丝技术制备纳米纤维膜,然后采用物理吸附或化学吸附的方法分离富集重金属,表面带有官能团（-COO-、-NH2、-SO32-、-SH、-S-）的纤维膜对重金属有很好的吸附性能.指出提高纳米纤维膜的制备产量和分析了解纳米纤维膜对重金属的选择性吸附原理,是纳米纤维膜分离富集重金属的研究方向.     

PFS法处理镍钼矿酸浸液萃钼余液的研究

采用聚合硫酸铁(PFS)法处理镍钼矿酸浸液萃钼余液中的重金属离子和化学耗氧量(COD),考察双氧水用量、PFS用量、搅拌时间、pH对余液中Zn~(2+)、Pb~(2+)、Ni~(2+)及COD含量的影响。结果表明,在双氧水用量20 mL/L、PFS用量60 mg/L、搅拌时间90 min、pH 11.0的条件下,COD可降至500 mg/L以下,去除率高达89%,重金属离子均达到GB 8978-1996污水综合排放一级标准。     

"帷幕内灰岩双含水层"赋存条件及疏干治理

大帷幕区回风斜井下掘时发生突水，分析认为是“上层灰岩含水层”中地下水通过Bo破碎带连通，导致掘进工作面涌水，帷幕形成后与分枝矿体共同的阻水作用形成了“帷幕内灰岩双含水层”的独特水文地质特征。通过实施矿体外围高角度、大密度、大孔深钻孔截水工程，实现了双含水层的疏干，解决了水害威胁及作业面涌水问题。     

Field Monitoring of a Permeable Reactive Barrier for Removal of Chlorinated Organics

The application of zero-valent iron (Fe0) in the funnel-and-gate permeable reactive barrier (PRB) installed at the Vapokon site, Denmark, was conducted in 1999 to remediate the groundwater contaminated by chlorinated aliphatic hydrocarbons (CAHs). Over the past 4?years, except in September 2002 and January 2003, about 92.4–97.5% CAH removal could be achieved with the PRB. Although there was a continuous decrease in total alkalinity (90.3%), calcium (81.7%), and sulfate (69.2%) ions in the groundwater crossing the PRB, probably caused by mineral precipitation and resulting in 0.88% porosity loss per year, no noticeable deterioration of the barrier’s performance was observed between March 2000, and August 2003. Instead, climatic variation in the barrier’s performance on CAH dechlorination was examined. The dechlorination rates in the cold season (January 2003 and March 2000) were generally smaller than those in the hot season (August 2003, September 2000, and September 2001). Besides, 1,2-dichloroethane and dichloromethane, which were proven to be not treatable by Fe0, could also be removed with the PRB, thereby suggesting enhancement from Fe0 adsorption or microbial degradation.     

Removal of Cd (II) and Pb (II) from aqueous environment using Moringa Oleifera seeds as biosorbent: A low cost and ecofriendly technique for water purification

Ever-growing list of chemical contaminants released into the environment through excessive industrialization on a large scale includes numerous chemical pollutants more prominently heavy metals. The discharge of heavy metals in aqueous system and their removal have been a challenging task for environmentalists for last one decade. Keeping these views in mind, the present study highlights the efficacy of shelled Moringa oleifera seeds (SMOS) in decontaminating Cd (II) and Pb (II) ions from aqueous environment both present as single metal and as binary metal solution. The extent of adsorption capacity for Cd (II) and Pb (II) on Moringa oleifera seeds for binary metal ions [76.59% and 81.10%] was found to be low as compared to single metal ions [85.10% and 96.10%]. Morphological changes observed in Scanning Electron Micrographs of native and treated SMOS indicates the existence of biosorption phenomenon. Fourier Transform Infrared Spectrometry of the exhausted seed biomass highlights amino acids-metal interaction responsible for sorption phenomenon. The sorption capacity of regenerated biomass remained almost constant after three cycle of sorption suggesting that the lifetime cycle was sufficient for continuous application.     

Improved Passive Treatment of Acid Mine Drainage in Mushroom Compost Amended with Crab-Shell Chitin

Crab-shell chitin, which is inherently high in calcium carbonate and nutrients, was tested as a multifunctional, fractional amendment to improve the effectiveness of spent mushroom compost (SMC), which is a low-cost, frequently used, but often underperforming substrate for treating acid mine drainage (AMD). Batch and continuous-flow column tests were used to evaluate different crab-shell/SMC mixtures for their ability to neutralize acidity, reduce sulfate, and remove metals in field-collected AMD. Alkalinity generation and the removal of manganese and sulfate were strongly correlated to the fraction of crab shell in the substrate: the treatment capacity increased from 36.7 L/kg for the traditional 90% SMC/10% limestone substrate up to 428 L/kg for 100% crab shell. The costs associated with adding crab shell to SMC were found to be minimal relative to the resulting improvement in water quality. Based on these data, it appears that a small fraction of crab shell (5–15%) does not provide a significant benefit over traditional compost and limestone substrates, but that larger fractions (50–100%) are much more efficient than traditional SMC substrates, especially for the removal of metals.     

Use of Immobilized Bentonite in Removal of Heavy Metals from Wastewater

Bentonite is known to adsorb toxic metal ions from aqueous solutions. In this study bentonite was immobilized in a polymer matrix of polysulfone in the form of spherical beads to remove cadmium and copper ions. For this purpose a bead-producing unit was fabricated. The procedure for making beads is described. The beads exhibited a porous surface and surface area of up to 20 m2∕g. 99.4% of beads were retained on a sieve size of 1.18 mm and were finer than 2.36 mm. Batch adsorption data was adequately described by the Freundlich isotherm model. The beads were able to remove more than 99% of copper and cadmium ions in the column mode. These beads can find application as filter media in the removal of toxic heavy metal ions from aqueous solutions.