酸性废水体系中硫酸钙反应结晶过程研究(英文)

The present work focused on the recycle of the sulfate and the metal ions from acidic wastewater dis charged by nonferrous metallurgical industry. The effects of the temperature, the reactant concentration, the stirring speed and the metal ions on the reactive crystallization process of calcium sulfate between sulfuric acid and lime were systematically investigated. The morphology of the precipitated crystals evolved from plateletlike and nee dlelike shape to rodlike shape when the temperature was increased from 25 to 70 ℃. An increase in the agglom.     

新型金属离子捕集剂—聚氧肟酸反相微乳液的合成及应用

采用微乳液聚合的方法合成了一种聚酰胺类的新型氧肟酸金属离子捕集剂。本文以液体石蜡作为分散相,Span-80作为乳化剂,与丙烯酰胺的环烷烃溶液复配成微乳液,加入盐酸羟胺并调节pH值进行羟肟化反应后,在低温下加入引发剂合成得到酰胺类氧肟酸的聚合物。研究了各种条件对产物性能的影响,采用红外光谱和粒度分析对产物结构进行表征,并考察其在金属离子废水处理中的脱除效果。结果表明,聚酰胺类氧肟酸金属离子捕集剂可以有效地捕捉到工业废水中的金属离子,且性能明显优于国内外同类产品。     

生物吸附剂及其在重金属废水处理中的应用进展

重金属离子严重危害人体健康,因此在废水处理中必须将其去除。传统去除重金属离子的方法很多,但都存在某些不足,近年发展起来的生物吸附技术,在水处理领域具有很好的应用前景。综述了近年来生物吸附剂在重金属废水处理中的应用情况,同时探讨了今后生物吸附法去除重金属的发展趋势。     

用海藻类生物吸附剂去除废水中的重金属离子——一种经济型新技术

Heavy metal pollution from industrial wastewater is a worldwide environmental issue. Biosorption of heavy metals by using biosorbents derived from various types of biomass has been shown to be effective for the uptake of heavy metal ions. In this study, biosorbents derived from the biomass of a group of marine macroalgae were used for the removal and recovery of heavy metal ions from aqueous solutions. Results indicated that the biosorbents have high uptake capacities and affinities for a number of heavy metal ions. The uptake capacities of the biosorbents were in the range of 1.0 to 1.5mmol·g-1 for divalent heavy metal ions. The kinetics of the uptake process was fast and the process can be used in both batch and fixed-bed operations. It appears that the biosorption process by using biosorbents from marine macroalgae can be an efficient and cost effective technology for the treatment of heavy metal containing wastewater.     

Sorption of Metal Ions on Acrylamidezirconium (IV) Arsenate and its Synthesis of PVC based Lead (II) Selective Electrode

Abstract

The adsorption of different metal ions on acrylamidezirconium (IV) arsenate has been studied. The effect of surfactant concentration (Tween 80‐R and Tritron X‐100) on sorption of different metal ions acrylamidezirconium (IV) arsenate was explored. The effect of experimental parameters such as contact time, temperature, and pH on adsorption of Pb²⁺ions was studied. The promising feature of the material is its specificity for Pb²⁺ ions. A new PVC based Pb²⁺ ion‐selective electrode using acrylamidezirconium (IV) arsenate as electro‐active material has been fabricated. The electrode works well over a wide range of concentration 1×10^?1 M–1×10^?7 M with a Nerstian slope of 30±1 mV per decade. The sensor shows the short response time of 20 seconds and can operate in the pH range of 2–7. The sensor can be used for the period of over 4 months with out deviation in response characteristics. The electrode has been successfully used as an indicator electrode for potentiometric titration of Pb²⁺ ions in solution against EDTA solution.     

离子交换技术在重金属工业废水处理中的应用

工业废水中重金属离子毒性大且不易生物降解,加上工业废水中的重金属离子浓度越来越高、排放标准控制越来越严,从而使此类废水的排放成为难题.目前,离子交换技术在重金属废水的达标排放处理中取得了不少成果,并在工程中有了卓有成效的应用,本文对此进行了综述.并详细讨论了影响该技术的各项参数,包括:pH值、溶液浓度,树脂用量、接触时间和运行条件等.     

Removal of Metal Ions From Wastewater With Roadside Tree Leaves

This paper reports on research related to the removal of heavy metal ions, such as lead, nickel, and zinc from wastewater by using tree leaves. Twelve different kinds of tree leaves were tested at room temperature. The experiments were carried out with 2 g of 40-50 mesh leaves in 200 mL synthetic wastewater containing about 50 mg/L metal ions. The initial pH of the synthetic wastewater was about 5. The experiments showed that the highest removal rates were 96% for lead (Pb ++ ), 61.7% for nickel (Ni ++ ), and 71.3% for zinc (Zn ++ ), compared with 93.9% for lead, 68.5% for nickel, and 72.1% for zinc achieved by activated carbon. Tree leaves appear to beagoodadsorbent for metal ion removal from wastewater.     

Removal of Metal Ions From Wastewater With Roadside Tree Leaves

This paper reports on research related to the removal of heavy metal ions, such as lead, nickel, and zinc from wastewater by using tree leaves. Twelve different kinds of tree leaves were tested at room temperature. The experiments were carried out with 2 g of 40-50 mesh leaves in 200 mL synthetic wastewater containing about 50 mg/L metal ions. The initial pH of the synthetic wastewater was about 5. The experiments showed that the highest removal rates were 96% for lead (Pb ++ ), 61.7% for nickel (Ni ++ ), and 71.3% for zinc (Zn ++ ), compared with 93.9% for lead, 68.5% for nickel, and 72.1% for zinc achieved by activated carbon. Tree leaves appear to beagoodadsorbent for metal ion removal from wastewater.     

吸附法处理重金属废水的研究进展

吸附法处理重金属废水是将废水中的金属离子用吸附剂从水体中分离。介绍了黑曲霉牡蛎壳粉、改性沸石、机制竹炭、改性膨润、啤酒酵母、改性累托石等吸附剂对重金属废水的处理。对这些吸附法做了比较和评价,并对今后的研究方向提出了建议。     

Removal of Anionic Metal Ions from Wastewater by Hydroxide-type Adsorbents

Generally speaking, anionic metal concentrations in wastewater from industries and mineral processing plants are well above the allowed limits for effluent set by the Ministry of Environment of Japan. Nowadays, the removal of anionic ions has been considered difficult and development of new process is desperately needed. In this paper, we report the development of three hydroxide-type adsorbents, illustrating their adsorption efficiency in removing As, Se, Mo and Sb ions from aqueous solutions. The main finding of this work was that the adsorption behavior was influenced very much by both the pH and the adsorbent concentration. Nevertheless, the newly developed hydroxide-type adsorbents were very effective in reducing the concentration of those anionic ions.     

Investigation of adsorption of lead,mercury and nickel from aqueous solutions onto carbon aerogel

Recently a new form of activated carbon has appeared: carbon aerogel (CA). Its use for the removal of inorganic (and especially metal ions) has not been studied. In the present study, the adsorption of three metal ions, Hg(II), Pb(II) and Ni(II), onto carbon aerogel has been investigated. Batch experiments were carried out to assess adsorption equilibria and kinetic behaviour of heavy metal ions by varying parameters such as agitation time, metal ions' concentration, adsorbent dose and pH. They facilitated the computation of kinetic parameters and maximum metal ion adsorption capacities. Increasing the initial solution pH (2–10) and carbon concentration (50–500 mg per 50 cm³) increases the removal of all three metal ions. A decrease of equilibrium pH with an increase of metal ion concentration led us to propose an adsorption mechanism by ion exchange between metal cations and H⁺ at the carbon aerogel surface. Carboxylic groups are especially involved in this adsorption mechanism. Langmuir and Freundlich isotherm models were used to analyse the experimental data of carbon aerogel. The thermodynamics of the metal adsorption was also investigated for the practical implementation of the adsorbent. The sorption showed significant increase with increase of temperature. Kinetics models describing the adsorption of Hg(II), Pb(II) and Ni(II) ions onto carbon aerogel have been compared. Kinetics models evaluated include the pseudo‐first order and second order model. The parameters of the adsorption rate constants have been determined and the effectiveness of each model assessed. The result obtained showed that the pseudo‐second order kinetic model correlated well with the experimental data and better than the pseudo‐first order model examined in the study. Mass transfer coefficients obtained can be useful in designing wastewater treatment systems or in the development of environmental technologies. Copyright © 2005 Society of Chemical Industry     

Removal and recovery of nickel ion from wastewater of electroless plating by reduction crystallization

Wastewater treatment after electroless nickel plating runs has been known to be difficult and this has been a subject of worldwide concern. Discarding wastewater of electroless nickel plating into sea was prohibited under the London Dumping Treaty since 1996. We have studied on recovering nickel from wastewater by reduction crystallization. In this study, the characteristics of nickel ion removal and recovery were investigated in the process of reduction crystallization using a laboratory scale batch crystallizer (500 ml), in order to propose a new process for wastewater treatment from nickel plating. In the reduction crystallization, which can use hypophosphite ion as a reducing agent for nickel ion in the wastewater, nickel ion could be recovered as a form of nickel metal by seeding nickel powder having large specific surface area.     

新型工艺处理含金属离子的有机废水

本文研究了金属离子Cu2+及电流对微生物降解有机物(C6H12O6)的影响,开发了外加电场作用下活性污泥法处理含Cu2+有机废水的新型工艺。试验结果表明:Cu2+对微生物降解有机物有明显的抑制作用;50mA的电流对微生物活性没有影响,100mA的电流对微生物活性有明显的抑制作用;对C6H12O6含量为500mg L,Cu2+含量为10mg L的重金属离子有机废水,在曝气池两侧上加电场,电流强度为50mA,经处理后,出水C6H12O6质量浓度为20mg L～30mg L,Cu2+质量浓度为0 5mg L,达到国家废水排放标准。     

金属杂质离子对双氰胺介稳区宽度的影响研究

双氰胺是重要的电石深加工产品,是多种重要化工产品的中间体,广泛应用于农药、医药、电子、化肥、环保处理剂等领域。在双氰胺的生产过程中,结晶过程是关键环节,但由于生产双氰胺的原料中带入多种金属离子,这些离子影响双氰胺的介稳区宽度,进而影响双氰胺产品的质量。本文考察了金属杂质离子（ Ca2＋、 Mg2＋、 Fe3＋、 Al3＋）对双氰胺介稳区宽度的影响。实验结果表明,四种金属离子对双氰胺介稳区均有增大作用,金属杂质离子的存在对DCD成核过程起着较强的抑制作用。     

流态化诱导结晶沉积法处理无机废水的研究进展

介绍了流态化诱导结晶沉积法的原理,综述了该方法在无机废水处理中的应用研究,着重介绍其在重金属离子、磷酸盐、氟离子以及水的软化处理方面的研究进展。在重金属废水处理上的实际研究工作表明,该技术具有反应快、占地面积小、无污泥产生等优点,具有广泛应用前景。     

Preparation and adsorption behaviors of ethylene diamine tetraacetic acid modified zwitterionic hybrid materials

Novel ethylene diamine tetraacetic acid (EDTA)‐modified zwitterionic hybrid materials were prepared via a sol–gel process. Their adsorption performances for Pb²⁺ ions were examined. Fourier transform infrared spectroscopy confirmed the reaction products. Thermogravimetric analysis revealed that the thermal stability of these hybrid materials could reach 200°C. Differential scanning calorimetry measurement showed that the addition of titanium butoxide could impact the crystallization transformation of these materials. Field emission scanning electron microscopy images showed that EDTA modification induced a decrease in the particle size. Adsorption experiments demonstrated that the optimal initial pH was 5. Moreover, we observed that the adsorptions for Pb²⁺ ions followed the Lagergren pseudo‐second‐order kinetic model, intraparticle diffusion, and Langmuir isotherm model. In addition, we found that the maximal Langmuir constant was 0.86 mmol/g. The negative Gibbs free energy values suggested that Pb²⁺ adsorption onto these samples was spontaneous in nature. The desorption experiment indicated that these samples could be recovered with aqueous HCl solution as a desorbent. These results suggest that the synthesized EDTA‐modified zwitterionic hybrid materials are promising adsorbents that could be used to separate and recover heavy‐metal ions from polluted wastewater. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39801.     

Metal ion separation and recovery from environmental sources using various flotation and sorption techniques

Flotation is a gravity separation process that originated from processing of minerals, and has nowadays found wide application, for instance, in industrial waste‐water treatment. It is also useful in the concentration of a variety of dissolved chemical species often following a sorption process. The present review paper focuses on the removal of heavy metal ions from aqueous solution. The process mechanisms involved are either sorptive flotation where metal bonding agents, including biosorbents, are added and the subsequent complexes are separated downstream by flotation or other conventional flotation techniques, such as ion flotation are used. In the laboratory experiments described in this paper, zinc has been used as an example, but in addition copper, nickel, arsenic, etc. are considered. A new hybrid flotation–microfiltration cell is also introduced. Copyright © 2010 Society of Chemical Industry     

Electron Beam Grafted Polymer Adsorbent for Removal of Heavy Metal Ion from Aqueous Solution

Abstract

An electron beam grafted adsorbent was synthesized by post irradiation grafting of acrylonitrile (AN) on to a non‐woven thermally bonded polypropylene (PP) sheet using 2 MeV electron beam accelerator. The grafted poly(acrylonitrile) chains were chemically modified to convert a nitrile group to an amidoxime (AMO) group, a chelating group responsible for metal ion uptake from an aqueous solution. The effect of various experimental variables viz. dose, dose rate, temperature, and solvent composition on the grafting extent was investigated. PP grafted with the amidoxime group (AMO‐g‐PP) was tested for its suitability as an adsorbent for removal of heavy metal ions such as Co²⁺, Ni²⁺, Mn²⁺, and Cd²⁺ from aqueous solution. Langmuir and Freundlich adsorption models were used to investigate the type of adsorption of these ions. The adsorption capacities of the adsorbent for the metal ions were found to follow the order Cd²⁺>Co²⁺>Ni²⁺>Mn²⁺. The kinetics of adsorption of these ions indicated that the rate of adsorption of Cd²⁺ was faster than that of other ions studied.     

基于纳米探针的压电重金属离子检测

文章通过在QCM（Quartz Crystal Microbalance,石英晶体微天平）表面形成纳米复合物引起质量变化来检测溶液中的痕量重金属离子。先让金属离子在羧基修饰的QCM表面进行络合吸附,然后加入羧基修饰的金纳米粒子,使之与QCM表面吸附的重金属离子结合,在QCM表面形成一层三明治结构的纳米复合物,引起QCM谐振频率明显下降。该方法大大提高了QCM检测重金属离子的灵敏度,且具有重现性好、传感器易再生等特点。     

Sol‐Gel Materials for High Capacity,Rapid Removal of Metal Contaminants

Abstract

An environmental waste remediation method is presented where porous cylindrical monoliths are interposed as septa between a solution contaminated with metal ions and a solution of a precipitant. Precipitant and contaminant diffuse and generate precipitate nano‐ and micro‐particles inside the monoliths. Two types of silica sol‐gel monoliths were tested. One class of materials was prepared following a conventional base‐catalyzed route which yielded fragile silica monoliths with pore diameters on the order of 7–10 nm. A second class of materials material consisted of templated silica macroporous monoliths that were cross‐linked with diisocyanate. These materials had pore diameters on the order of microns and were mechanically extremely strong, having a Young modulus in excess of 400 MPa. Both types of silica gel monoliths proved very versatile, and allowed to precipitate a wide variety of metal ions, including toxic metals such as Cd²⁺, and fission by‐products such as lanthanides and Sr²⁺. The capacity of the gel monoliths was also very high, at least 20 times higher than the capacity of conventional derivatized gels. Most importantly, precipitation inside the macroporous gels was a factor 7–8 more rapid than in microporous gels. The results indicate that macroporous cross‐linked sol‐gel monoliths are a promising material for the development of efficient, mechanically strong filter elements for environmental remediation.