天然斜发沸石水热转化Na-P沸石及其吸附镉的性能研究

以河北承德围场地区天然沸石为原料,对其进行水热改性制备Na-P沸石。采用X射线衍射仪、X射线光电子能谱仪、气体吸附仪、扫描电镜和能谱分析仪等对材料进行表征分析,采用Cd2+离子评价材料的重金属离子去除性能。研究碱处理浓度、水热温度和时间对天然沸石结构的影响规律,着重研究所制备Na-P沸石的组成结构特征及重金属离子去除性能。结果表明:在NaOH浓度3 mol/L、水热温度100 ℃、水热时间12 h的条件下,斜发沸石可转化为纯度较高的Na-P沸石。所得材料对Cd2+的吸附容量为35.7 mg/g,较天然沸石提升7倍。Na-P沸石性能的提升主要归功于其较低的硅铝比和较高的表面Na+含量。      

沸石在水和废水处理中的应用

沸石是一种天然廉价矿物,可用于去除水中氨氮、有机物、浊度、重金属离子和含氧酸阴离子。本文综述了沸石在水和废水处理中的应用,探讨了沸石吸附机理、规律和影响因素,简述了从粉煤灰中合成沸石的方法,并总结了应用方面存在的问题。     

Treatment of acid mine water by use of heavy metal precipitation and ion exchange

Acid mine water from a South African gold mine was characterised and treated by the precipitation of heavy metals with lime and sulphides, followed by ion exchange. The novelty of the proposed process lies in the use of carrier magnetic materials for more effective separation of water and solids, as well as the oxidation pretreatment that is also used to sterilize the water. The process can generate very, pure water from acid mine water with a great flexibility and an acceptable cost. The oxidation and precipitation of heavy metals with lime and subsequent sulphide-carrier magnetic separation appeared to be particularly suitable for the removal of heavy metal ions from the effluent of the particular gold mine that was investigated. The cation exchange resin IR120 can be used to reduce the salinity of the effluent of mine water after removal of heavy metals by precipitation. Low cost sulphuric acid can be used as the cation resin regenerator. The anion exchange resin A375 could reduce the anions (sulphate, chloride, bromide and fluoride) to acceptably low levels in the mine water after precipitation of heavy metals. A combination of sodium hydroxide and saturated lime solution can be used as the anion resin regenerator. A mixture of acidic gypsum from the cation elution section and alkaline gypsum from the anion elution section could generate high quality gypsum as byproduct, which could be sold as a valuable raw material to the gypsum industry, to offset process cost. Although these experiments were conducted on the acid mine water of a specific mine, the process could be extended to other mine waters contaminated with heavy metals and high salinities.     

某天然片沸石的改性研究

采用典型的酸、碱、盐,利用离子交换的方法对天然片沸石进行了改性,研究了活化改性条件对沸石改性效果的影响,探讨了NaOH改性天然沸石的机理。结果表明,天然片沸石改性后,吸附性能和离子交换性能得到进一步改善,对重金属离子的吸附能力显著提高。     

Biosorption of cadmium by green coconut shell powder

The effective removal of heavy metals from aqueous wastes is among the most important issues for many industrialized countries. The traditional treatment methods used to remove heavy metals from wastewaters have certain disadvantages such as incomplete metal removal, high reagent and energy requirements, generation of toxic sludge or other waste products that require disposal. The search for alternative and innovate treatment techniques has focused attention on the use of biological materials for metal removal and recovery technologies. Biosorption has gained important credibility during recent years because of its good performance and low cost.In the present study, the biosorption capacity of powder from coconut shell was studied for cadmium. The adsorption capacity of biomass was investigated by batch experiments. The influence of metal ion concentration and pH were evaluated and the results were fitted using adsorption isotherm models. The kinetic of cadmium biosorption was also investigated.     

应用高梯度磁选技术处理含铜废水的试验研究

目前,去除水中重金属离子的常用方法存在处理成本较高、易造成二次污染等问题,为此,以浓度为100 mg/L的硫酸铜溶液作为模拟含重金属离子的废水,采用铁氧体沉淀—高梯度磁选分离技术去除水中铜离子。结果表明:在溶液初始pH为10.47,n(FeCl2)∶n(CuSO4)=1.0时,沉淀反应后铜离子沉淀率为99.98%,水中残余铜离子浓度仅0.0127 mg/L;生成的沉淀中按n(Fe3O4)∶n(Cu2+)=0.8加入磁铁矿作为磁种,在背景磁感应强度为1.0 T,采用直径为0.6 mm的网状介质盒,经高梯度强磁选可将93.39%的沉淀物快速分离出来。试验结果为应用高梯度磁选技术处理含重金属离子废水提供了理论依据,为该技术的工业应用提供了技术支撑。     

粉煤灰对二价金属离子的吸附特性

考察了粉煤灰对二价金属离子的吸附性能.结果表明，粉煤灰可有效吸附水溶液中的重金属离子.吸附由易到难次序为：Pb>Cu>Cd>Zn.随pH升高，去除率增加.吸附在约60 min内达到平衡.等温吸附数据符合Freundlich模型，但在pH=4.5时表现为单一线性区，而在pH= 6和pH=8时表现为2个线性区.粉煤灰对金属离子的吸附明显受到其它共存离子的影响，Cd与Pb之间存在较强的协同吸附作用.对实际废水的测试表明，粉煤灰可同时有效去除工业废水中多种金属离子.     

沸石除磷复合吸附剂的制备及其性能研究

针对市政污水二级出水中磷含量较高的问题,结合国内外相关研究,采用廉价的天然沸石为基体材料,选择镧离子为无机载入离子,氯化镧为无机载入剂对沸石进行复合处理,处理后的沸石除磷能力提高了83.83个百分点,最佳复合条件为pH=10,LaCl₃浓度0.4%,复合时间1 h,复焙烧失温度200 ℃,复焙烧失时间1 h。复合材料吸附磷的等温线较好地符合Langmuir等温线模型。与幂函数相比,叶洛维奇吸附动力学方程能更好地阐明复合吸附材料在除磷过程中的吸附机理。通过对材料进行扫描电镜对比测试分析,可知在制备复合吸附材料的过程中,沸石表面形貌、微观孔径大小和形状均发生了变化。     

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。     

镁剂在重金属离子脱除方面的应用研究进展

对以氧化镁、氢氧化镁为代表的镁剂在废水中重金属离子脱除方面的应用进展进行了评述,包括含铬废水、含镍废水、含铅废水、含镉废水、含铜铁等工业废水中单一重金属离子的去除以及多种重金属离子的同时脱除,并探讨了其对重金属离子的去除机理,展望了应用前景。     

Laboratory evaluation of Fe0 barriers to treat acidic leachates

In the present study, flow-through column experiments using a series of continuous-flow columns were conducted to investigate the performance of Fe⁰ permeable reactive barriers (PRB) for the treatment of acidic leachates generated in active or abandoned mining and waste disposal sites. Simulated AMD solutions of low and high metal ion concentration were pumped at different flow rates into the laboratory system. Concentration profiles under steady-state transport conditions were developed by measuring metal ion concentration at various sampling ports. Results show that metal ion removal is mainly accomplished via redox reactions that initiate precipitation of mineral phases. Sulfate green rust was identified from the analysis of precipitates formed on the iron surface; sulfate and heavy metals uptake by green rust is a secondary clean up mechanism. Experimental results as well as geochemical modeling by PHREEQC-2 indicate that cadmium and copper are removed by redox reactions while aluminum, manganese, nickel, cobalt and zinc are mainly removed as metal hydroxides. It is therefore seen than zero-valent iron barriers can be used as an environmentally and economically viable remediation technology for the clean up of acidic leachates loaded with several inorganic contaminants and sulfates and the subsequent prevention of groundwater contamination.     

Removal of Toxic Metal Ions from Sungun Acid Rock Drainage Using Mordenite Zeolite,Graphene Nanosheets,and a Novel Metal–Organic Framework

We evaluated the sorptive properties of mordenite zeolite (MOR), a copper terephthalate metal–organic framework (MOF), and graphene oxide (GO) and their potential use in treating acid rock drainage (ARD) containing Fe³⁺, Cu²⁺, Mn²⁺, Zn²⁺, Pb²⁺, and Cd²⁺ ions. MOR was prepared via a hydrothermal method, MOF was prepared via a solvothermal method, and few-layered GO nanosheets were synthesized using Hummers’ method. The aqueous contaminants were removed by chemico-physical sorption and ion exchange in batch tests. It proved possible to dramatically improve removal efficiency and sorptive capacity by optimizing experimental conditions. Magnetic MOF crystals were more efficient in removing metals than the MOR and GO. Sorption tests using ARD from the Sungun copper mine and a multi-component solution containing cationic metal species revealed that both GO nanosheets and magnetic MOF have great potential for ARD treatment.     

膨润土和沸石的改性及其在废水处理中的应用

论述了我国含氮、磷、氟及重金属离子废水的来源，膨润土和沸石及其改性产品的物理化学性能，膨润土和沸石及其改性产品在处理含氮、磷、氟及重金属离子废水中的开发现状与应用前景。     

赣南某红土镍矿常压酸浸液中杂质离子的除去

赣南某红土镍矿常压酸浸液中含有铁、镁、铜、铅、锌等杂质离子,且这些杂质离子与镍离子分离较困难。采用黄钠铁矾法去除铁离子,达到了99%的去除率;采用硫化钠沉淀法去除铜、铅、锌等重金属离子,达到了90%的去除率;采用氟化钠法去除镁离子,达到了90%的去除率;各作业段镍离子作业损失率分别为15%、12%、5%。     

水体磁化参数对飞灰中锌的浮选去除效果的影响规律及其模型

为掌握磁化水体系下浮选去除生活垃圾焚烧飞灰中锌的影响规律,采用正交试验进行了磁化水体系下浮选去除飞灰中锌的研究,在此基础上利用正交多项式回归分析方法建立了磁化水体系下浮选去除飞灰中锌的数学模型。结果表明,线圈匝数对飞灰中锌的去除率的影响作用显著。在磁化时间为25min、电流频率为48 kHz、线圈匝数为90圈、波形为三角波的条件下采用一次粗选的流程可获得69.536%的锌去除率,指标较为理想。磁化水中浮选去除锌的数学模型为 = -0.2825X_D+94.821。在设定的条件范围内,该模型对飞灰中锌的去除率的预测值与试验结果的误差在±3.94%之间,准确性较高,对现场的生产调试具有一定的指导意义。     

化学废水中重金属离子浓度软测量方法研究

为了降低废水重金属离子浓度测量误差,结合现有的研究理论,提出化学废水中重金属离子浓度软测量方法。采用电导率计和密度计组成可用于废水检测现场的检测装置,利用安装金属铁板的电解槽对化学废水进行电化学检测;通过电解液溶解氧化铁离子,生成吸附重金属离子的氢氧化铁,定量描述氢氧化铁絮体吸附能力,建立重金属离子浓度软测量模型;根据装置检测到的废水电导率、密度、温度,计算软测量模型待辨识的变量参数,确定离子浓度软测量值。将某化学废水处理厂作为研究对象,采集不同类型废水水样,把检测装置安装在废水排放出口,现场检测废水中的钴离子、铅离子、钨离子浓度。结果表明,3类重金属离子浓度软测量值和实际值的相对误差都小于14%,软测量精度较高。     

The use of flotation techniques in the remediation of heavy metal contaminated sediments and soils: an overview of controlling factors

The potential use of flotation as a remediation technique for heavy metal contaminated sediments and soils is discussed. In general, the flotation process is much less selective for heavy metals in sediments and soils compared to the results obtained in common mineral ore flotation practice. The following factors could be isolated as responsible for this different behaviour: the metal distribution over the different geochemical phases (metal partitioning), the metal distribution over the different size fractions (metal fractionation) and the presence of organic matter (humic substances). These controlling factors were illustrated by performing Denver flotation experiments on a natural canal sediment and column flotation tests on synthetic sediments.It is emphasised that sequential extraction techniques can be used as a tool for determining the original metal partitioning in sediments and soils and as a result helps to select the most appropriate procedure of flotation (e.g. a phase-specific collector). A chemical pre-treatment step (e.g. sulphidisation, hydroxylation) prior to the flotation of sediments and soils can be beneficial depending on the in-situ metal partitioning and serves to transfer heavy metals, which are associated with different speciation sources (oxides, sulphides, clay minerals, organic matter, etc.), into one unique-good floatable-chemical speciation form (e.g. oxides, sulphides). The selective flotation of metal-bearing particles from fine-textured sediments and soils is very difficult and therefore a major challenge for future research is to tackle the problems related with the flotation of these fines. Organic matter, which is rather selectively flotated, has an adverse effect on the metal (sulphide) flotation selectivity due to its adsorption onto mineral surfaces.     

氯化锰溶液的净化工艺

研究以工业废盐酸浸出低品位菱锰矿制得的氯化锰溶液净化工艺,主要包括除重金属和除钙、镁两部分,探讨金属锰粉去除重金属的净化效果以及用草酸和硫酸锰搭配使用去除钙和镁的新工艺.结果表明,氯化锰溶液采用金属锰粉作为重金属净化剂除杂效果较好,使用草酸和硫酸锰去除钙和镁杂质,不但实现了较好的除钙和除镁效果,而且得到了纯度和价值较高的副产品草酸钙,产品质量最终也达到了HG-T3816-2006标准.     

土壤改良介质对矿区先锋植物富集重金属能力的影响

为了探讨土壤改良介质对矿区先锋植物富集重金属能力的影响,选取郴州市柿竹园尾砂坝、高斯贝尔尾砂坝两处矿区土壤,采用沸石、40%沸石+60%草炭、80%沸石+20%食用菌下脚料3种介质以1∶15混合尾砂坝土壤形成改良土壤;利用改良土壤对多种先锋植物(小飞蓬、花叶水葱、苦菜)盆栽培育4个月,然后测定植物根、茎叶以及改良土壤中Cu、Zn、Pb的含量。结果表明,两处尾砂坝土壤中重金属含量关系为Zn>Pb>Cu,其中高斯贝尔尾砂坝土壤的Cu、Pb含量更高。柿竹园尾砂坝土壤中Zn含量约为Cu含量的6~25倍、Pb含量的3~10倍,而高斯贝尔尾砂坝中Zn含量约为Cu含量的6~8倍、Pb含量的1~3倍。土壤改良介质对植物富集Cu、Zn、Pb的能力均有影响,对于不同重金属污染的土壤,可采取多种植物混合种植,实现重金属污染土壤的修复。     

无氰电镀废水中重金属高效去除技术研究进展

概述了无氰电镀工艺废水中络合重金属高效去除新技术研究进展, 主要包括新型沉淀法(置换/螯合沉淀技术)、氧化还原破络法(重金属还原破络和配位剂氧化破络)及吸附法, 重点介绍了各技术原理、对络合重金属的处理效果、技术瓶颈。指出无氰电镀废水中重金属的综合回收势在必行, 低能耗/药耗的破络技术与吸附技术耦合工艺是未来重要的发展方向。