DOCSLIB.ORG

New Methods of Cleaning up Heavy Metal in Soils and Water

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
New Methods of Cleaning up Heavy Metal in Soils and Water ENVIRONMENTAL SCIENCE AND TECHNOLOGY BRIEFS FOR CITIZENS by M. Lambert, B.A. Leven, and R.M. Green New Methods of Cleaning Up Heavy Metal in Soils and Water Innovative solutions to an environmental problem This publication is published by the Hazard- ous Substance Research Centers as part of There are several options for treating Joplin. Here, mine spoils (locally called their Technical Outreach Services for Com- or cleaning up soils contaminated with chat) cover much of the open space in- munities (TOSC) program series of Environ- heavy metals. This paper discusses side the city, and contain high levels of mental Science and Technology Briefs for three of those methods. lead, zinc, and cadmium. Heavy metal Citizens. If you would like more information about the TOSC program, contact your re- contamination can be carried with soil gional coordinator: Introduction particles swept away from the initial At many sites around the nation, heavy areas of pollution by wind and rain. Northeast HSRC metals have been mined, smelted, or Once these soil particles have settled, New Jersy Institute of Technology Otto H. York CEES used in other industrial processes. The the heavy metals may spread into the 138 Warren St. waste (tailings, smelter slag, etc.) has surroundings, polluting new areas. Newark, NJ 07102 sometimes been left behind to pollute Cleanup (or remediation) technologies (201) 596-5846 surface and ground water. The heavy available for reducing the harmful ef- Great Plains/Rocky Mountain HSRC metals most frequently encountered in fects at heavy metal-contaminated sites Kansas State University this waste include arsenic, cadmium, include excavation (physical removal of 101 Ward Hall chromium, copper, lead, nickel, and the contaminated material), stabiliza- Manhattan, KS 66506 zinc, all of which pose risks for human tion of the metals in the soil on site, (800) 798-7796 health and the environment. They typi- and the use of growing plants to stop Great Lakes/Mid-Atlantic HSRC cally are spread out over former indus- the spread of contamination or to ex- A-124 Research Complex-Engineering trial sites and may cover acres of land. tract the metals from the soil Michigan State University Figure 1 shows one such site in south- (phytoremediation). East Lansing, MI 48824 (800) 490-3890 western Missouri, near the city of South/Southwest HSRC Environmental Science & Technology Program Georgia Tech Research Institute 229 Baker Building Atlanta, GA 30332 (404) 894-7428 Western Region HSRC Oregon State University 210 Strand Agriculture Hall Corvallis, OR 97331-2302 (800) 653-6110 Acknowledgment: Although this article has been funded in part by the U.S. Environmen- tal Protection Agency under assistance agree- ment R-819653, through the Great Plains/ Rocky Mountain Hazardous Substance Re- search Center, it has not been subjected to the agencys peer and administrative review Figure 1. Mine spoils called chat, near the city of Joplin, Missouri. and, therefore, may not reflect the views of Wind and rain can cause the chat to scatter, spreading heavy metal the agency. No official endorsement should contamination. be inferred. ENVIRONMENTAL SCIENCE AND TECHNOLOGY BRIEFS FOR CITIZENS PAGE 2 Excavation Table 1. Comparative costs for different types of heavy metal soil remediation Excavation and physical removal of the (Schnoor, 1997). soil is perhaps the oldest remediation Trype of Remediation Cdost/cubic mete Time Require method for contaminated soil. It is still in use at many locations, including resi- E0xcavation and removal $s100-$40 6-9 month dential areas contaminated with lead In situ fixation $s90-$200 6-9 month in southwestern Missouri. Advantages (including soil amendments) of excavation include the complete re- moval of the contaminants and the rela- P0hytoextraction $s15-$4 18-60 month tively rapid cleanup of a contaminated site (Wood, 1997). Disadvantages in- ity of heavy metals on site has many lead. Chemical reactions between the clude the fact that the contaminants advantages over excavation. One way phosphate and the lead cause a min- are simply moved to a different place, of stabilizing heavy metals consists of eral to form called lead pyromorphite. where they must be monitored; the risk adding chemicals to the soil that cause Lead pyromorphite and similar miner- of spreading contaminated soil and dust the formation of minerals that contain als called heavy metal phosphates are particles during removal and transport the heavy metals in a form that is not extremely insoluble. This means the of contaminated soil; and the relatively easily absorbed by plants, animals, or new minerals cannot dissolve easily in high cost. Excavation can be the most people. This method is called in situ (in water (Lambert et al., 1997). This has expensive option when large amounts place) fixation or stablization. This two beneficial effects. The minerals of soil must be removed or disposal as process does not disrupt the environ- (and the heavy metals) cannot be eas- hazardous or toxic waste is required ment or generate hazardous wastes. ily spread by water to pollute streams, (see Table 1). Instead, the heavy metal combines with lakes, or other groundwater. Also the the added chemical to create a less toxic heavy metal phosphates are less likely Stabilizing Metals in compound. The heavy metal remains to enter the food chain by being ab- the Soil in the soil, but in a form that is much sorbed into plants or animals that may Heavy metals can be left on site and less harmful. eat soil particles. Table 1 shows the cost treated in a way that reduces or elimi- of treating the soil by in situ fixation nates their ability toadversely effect One example of in situ fixation of heavy may be about half the cost of excava- human health and the environment. metals involves adding phosphate fer- tion and disposal of heavy metal con- This process is sometimes called stabi- tilizer as a soil amendment to soil that taminated soil. This method is rela- lization. Eliminating the bioavailabil- has high amounts of the heavy metal tively rapid and takes about the same amount of time as excavation. Use of Plants Growing plants can help contain or re- duce heavy metal pollution. This is of- ten called phytoremediation (EPA, 1988). It has the advantage of relatively low cost and wide public acceptance (Schnoor, 1997). It can be less than a quarter of the cost of excavation or in situ fixation. Phytoremediation has the disadvantage of taking longer to accom- plish than other treatment . Plants can be used in different ways. Sometimes a contaminated site is simply reveg- etated in a process called phytostabilization. The plants are used to reduce wind and water erosion that spread materials containing heavy metals. In one example, grass or tree buffers could reduce sediment loss from Figure 2. Test plots for evaluating revegetation of chat material in Galena, the chat piles at a contaminated site in Kansas. Here, tall fescue is being grown as a way of reducing sediment runoff Galena, Kansas, anywhere from 18% and the spread of heavy metal pollution. The bare center plot is a control in to 25% (Green, et al. 1997). If all of the which fescue was not planted. ground could be revegetated, sediment ENVIRONMENTAL SCIENCE AND TECHNOLOGY BRIEFS FOR CITIZENS Page 3 loss could be cut by approximately 70%. Conclusions sis Center Technology Evaluation However, it would be necessary to find During the 1990s, new methods have Report TE-98-01, 37. plants that could tolerate high levels of been developed to clean up heavy metal- heavy metals. Figure 2 shows a series contaminated soil. The expensive pro- Wood, P., 1997, Remediation Methods of several revegetation test plots on the cess of excavating and disposing con- for Contaminated Sites: in R. chat piles in Galena, Kansas. taminated soil has been augmented with Hester and R. Harrison, Contami- new methods that treat the soil in place. nated Land and Its Reclamation, Another way plants can be used to clean In situ fixation is a process that cre- the Royal Society of Chemistry, up heavy-metal contaminated soil is ates new chemical coumpounds in Cambridge, p. 47 71. called phytoextraction. Some plant spe- which heavy metals are much less cies can take up heavy metals and con- available to living things. This on-site U.S. Environmental Protection centrate them in their tissue. The cleanup is less disruptive to peoples Agency (US EPA), 1998, A Citizens plants can be harvested and the con- lives and to the environment compared Guide to Phytoremediation, Office taminated plant material disposed of to excavating and disposing contami- of Solid Waste and Emergency safely. Sometimes soil amendments are nated soils elsewhere. Phytoreme- Response (5102G) EPA 542-F-98- added to the soil to increase the ability diation uses plants by several methods 001 August 1998. of the plants to take up the heavy met- to contain or clean up heavy metals. als. One type of plant used for this Phytoremediation has the benefit of be- US EPA, 2000, Introduction to purpose is called Indian mustard. This ing a relatively low-cost, natural solu- Phytoremediation, National Risk plant has been used to extract lead from tion to an environmental problem. Management Research Laboratory, soil and reduce lead contamination at Office of Research and Develop- various contaminated sites. Other More information on these and other ment, EPA/600/R-99/107, February plants that may be used for new cleanup methods for contaminated 2000. phytoextraction include alfalfa, cab- soils and water is on the internet at bage, tall fescue, juniper, and poplar many sites, including <http://www.clu- n n n trees. in.org/>. ABOUT THE AUTHORS: Michael Lambert has a B.S. from Kansas State University, Another way plants are used to treat References an M.S.
Load more

Recommended publications
  • 5 Heavy Metals As Endocrine-Disrupting Chemicals
    5 Heavy Metals as Endocrine-Disrupting Chemicals Cheryl A. Dyer, PHD CONTENTS 1 Introduction 2 Arsenic 3 Cadmium 4 Lead 5 Mercury 6 Uranium 7 Conclusions 1. INTRODUCTION Heavy metals are present in our environment as they formed during the earth’s birth. Their increased dispersal is a function of their usefulness during our growing dependence on industrial modification and manipulation of our environment (1,2). There is no consensus chemical definition of a heavy metal. Within the periodic table, they comprise a block of all the metals in Groups 3–16 that are in periods 4 and greater. These elements acquired the name heavy metals because they all have high densities, >5 g/cm3 (2). Their role as putative endocrine-disrupting chemicals is due to their chemistry and not their density. Their popular use in our industrial world is due to their physical, chemical, or in the case of uranium, radioactive properties. Because of the reactivity of heavy metals, small or trace amounts of elements such as iron, copper, manganese, and zinc are important in biologic processes, but at higher concentrations they often are toxic. Previous studies have demonstrated that some organic molecules, predominantly those containing phenolic or ring structures, may exhibit estrogenic mimicry through actions on the estrogen receptor. These xenoestrogens typically are non-steroidal organic chemicals released into the environment through agricultural spraying, indus- trial activities, urban waste and/or consumer products that include organochlorine pesticides, polychlorinated biphenyls, bisphenol A, phthalates, alkylphenols, and parabens (1). This definition of xenoestrogens needs to be extended, as recent investi- gations have yielded the paradoxical observation that heavy metals mimic the biologic From: Endocrine-Disrupting Chemicals: From Basic Research to Clinical Practice Edited by: A.
    [Show full text]
  • Identification and Quantification of Arsenic Species in Gold Mine Wastes Using Synchrotron-Based X-Ray Techniques
    Identification and Quantification of Arsenic Species in Gold Mine Wastes Using Synchrotron-Based X-ray Techniques Andrea L. Foster, PhD U.S. Geological Survey GMEG Menlo Park, CA Arsenic is an element of concern in mined gold deposits around the world Spenceville (Cu-Au-Ag) Lava Cap (Nevada) Ketza River (Au) Empire Mine (Nevada) low-sulfide, qtz Au sulfide and oxide ore Argonaut Mine (Au) bodies Don Pedro Harvard/Jamestown Ruth Mine (Cu) Kelly/Rand (Au/Ag) Goldenville, Caribou, and Montague (Au) The common arsenic-rich particles in hard-rock gold mines have long been known Primary Secondary Secondary/Tertiary Iron oxyhydroxide (“rust”) “arsenian” pyrite containing arsenic up to 20 wt% -1 Scorodite FeAsO 2H O As pyrite Fe(As,S)2 4 2 Kankite : FeAsO4•3.5H2O Reich and Becker (2006): maximum of 6% As-1 Arseniosiderite Ca2Fe3(AsO4)3O2·3H2O Arsenopyrite FeAsS Jarosite KFe3(SO4)2(OH)6 Yukonite Ca7Fe12(AsO4)10(OH)20•15H2O Tooleite [Fe6(AsO3)4(SO4)(OH)4•4H2O Pharmacosiderite KFe (AsO ) (OH) •6–7H O arsenide n- 4 4 3 4 2 n = 1-3 But it is still difficult to predict with an acceptable degree of uncertainty which forms will be present • thermodynamic data lacking or unreliable for many important phases • kinetic barriers to equilibrium • changing geochemical conditions (tailings management) Langmuir et al. (2006) GCA v70 Lava Cap Mine Superfund Site, Nevada Cty, CA Typical exposure pathways at arsenic-contaminated sites are linked to particles and their dissolution in aqueous fluids ingestion of arsenic-bearing water dissolution near-neutral, low
    [Show full text]
  • Background Document on Cadmium ______
    Hazardous Substances Series -------------------------------------------------------------------------------------------------------------------------------------------- Cadmium OSPAR Commission 2002 (2004 Update) OSPAR Commission, 2002: OSPAR Background Document on Cadmium _______________________________________________________________________________________________________ The Convention for the Protection of the Marine Environment of the North-East Atlantic (the “OSPAR Convention”) was opened for signature at the Ministerial Meeting of the former Oslo and Paris Commissions in Paris on 22 September 1992. The Convention entered into force on 25 March 1998. It has been ratified by Belgium, Denmark, Finland, France, Germany, Iceland, Ireland, Luxembourg, Netherlands, Norway, Portugal, Sweden, Switzerland and the United Kingdom and approved by the European Community and Spain. La Convention pour la protection du milieu marin de l'Atlantique du Nord-Est, dite Convention OSPAR, a été ouverte à la signature à la réunion ministérielle des anciennes Commissions d'Oslo et de Paris, à Paris le 22 septembre 1992. La Convention est entrée en vigueur le 25 mars 1998. La Convention a été ratifiée par l'Allemagne, la Belgique, le Danemark, la Finlande, la France, l’Irlande, l’Islande, le Luxembourg, la Norvège, les Pays-Bas, le Portugal, le Royaume-Uni de Grande Bretagne et d’Irlande du Nord, la Suède et la Suisse et approuvée par la Communauté européenne et l’Espagne. © OSPAR Commission, 2002. Permission may be granted by the publishers for the report to be wholly or partly reproduced in publications provided that the source of the extract is clearly indicated. © Commission OSPAR, 2002. La reproduction de tout ou partie de ce rapport dans une publication peut être autorisée par l’Editeur, sous réserve que l’origine de l’extrait soit clairement mentionnée.
    [Show full text]
  • Cadmium- Toxfaqs™
    Cadmium- ToxFAQs™ CAS # 7440-43-9 This fact sheet answers the most frequently asked health questions (FAQs) about cadmium. For more information, call the CDC Information Center at 1-800-232-4636. This fact sheet is one in a series of summaries about hazardous substances and their health effects. It is important you understand this information because this substance may harm you. The effects of exposure to any hazardous substance depend on the dose, the duration, how you are exposed, personal traits and habits, and whether other chemicals are present. HIGHLIGHTS: Exposure to cadmium happens mostly in the workplace where cadmium products are made. The general population is exposed from breathing cigarette smoke or eating cadmium contaminated foods. Cadmium damages the kidneys, lungs, and bones. Cadmium has been found in at least 1,014 of the 1,669 National Priorities List (NPL) sites identified by the Environmental Protection Agency (EPA). What is cadmium? How might I be exposed to cadmium? Cadmium is a natural element in the earth’s crust. It is • Eating foods containing cadmium; low levels are usually found as a mineral combined with other elements found in all foods (highest levels are found in leafy such as oxygen (cadmium oxide), chlorine (cadmium vegetables, grains, legumes, and kidney meat). chloride), or sulfur (cadmium sulfate, cadmium sulfide). • Smoking cigarettes or breathing cigarette smoke. All soils and rocks, including coal and mineral fertilizers, • Breathing contaminated workplace air. contain some cadmium. Most cadmium used in the United States is extracted during the production of other metals • Drinking contaminated water. like zinc, lead, and copper.
    [Show full text]
  • Tracing Contamination Sources in Soils with Cu and Zn Isotopic Ratios Z Fekiacova, S Cornu, S Pichat
    Tracing contamination sources in soils with Cu and Zn isotopic ratios Z Fekiacova, S Cornu, S Pichat To cite this version: Z Fekiacova, S Cornu, S Pichat. Tracing contamination sources in soils with Cu and Zn isotopic ratios. Science of the Total Environment, Elsevier, 2015, 517, pp.96-105. 10.1016/j.scitotenv.2015.02.046. hal-01466186 HAL Id: hal-01466186 https://hal.archives-ouvertes.fr/hal-01466186 Submitted on 19 Mar 2019 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Tracing contamination sources in soils with Cu and Zn isotopic ratios Fekiacova, Z.1, Cornu, S.1, Pichat, S.2 1 INRA, UR 1119 Géochimie des Sols et des Eaux, F-13100 Aix en Provence, France 2 Laboratoire de Géologie de Lyon (LGL-TPE), Ecole Normale Supérieure de Lyon, CNRS, UMR 5276, 69007 Lyon, France Abstract Copper (Cu) and zinc (Zn) are naturally present and ubiquitous in soils and are im- portant micronutrients. Human activities contribute to the input of these metals to soils in dif- ferent chemical forms, which can sometimes reach a toxic level for soil organisms and plants. Isotopic signatures could be used to trace sources of anthropogenic Cu and Zn pollution.
    [Show full text]
  • Understanding Variation in Partition Coefficient, Kd, Values: Volume II
    United States Office of Air and Radiation EPA 402-R-99-004B Environmental Protection August 1999 Agency UNDERSTANDING VARIATION IN PARTITION COEFFICIENT, Kd, VALUES Volume II: Review of Geochemistry and Available Kd Values for Cadmium, Cesium, Chromium, Lead, Plutonium, Radon, Strontium, Thorium, Tritium (3H), and Uranium UNDERSTANDING VARIATION IN PARTITION COEFFICIENT, Kd, VALUES Volume II: Review of Geochemistry and Available Kd Values for Cadmium, Cesium, Chromium, Lead, Plutonium, Radon, Strontium, Thorium, Tritium (3H), and Uranium August 1999 A Cooperative Effort By: Office of Radiation and Indoor Air Office of Solid Waste and Emergency Response U.S. Environmental Protection Agency Washington, DC 20460 Office of Environmental Restoration U.S. Department of Energy Washington, DC 20585 NOTICE The following two-volume report is intended solely as guidance to EPA and other environmental professionals. This document does not constitute rulemaking by the Agency, and cannot be relied on to create a substantive or procedural right enforceable by any party in litigation with the United States. EPA may take action that is at variance with the information, policies, and procedures in this document and may change them at any time without public notice. Reference herein to any specific commercial products, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government. ii FOREWORD Understanding the long-term behavior of contaminants in the subsurface is becoming increasingly more important as the nation addresses groundwater contamination. Groundwater contamination is a national concern as about 50 percent of the United States population receives its drinking water from groundwater.
    [Show full text]
  • Arsenic and Lead Contamination in Oklahoma Soils Arsenic and Lead Are Naturally Occurring Elements Present in Rocks
    Arsenic and Lead Contamination in Oklahoma Soils Arsenic and lead are naturally occurring elements present in rocks. As these rocks erode, arsenic and lead get in soils, waters and plants. The United States Geological Survey (USGS) reports an average of 7.4 parts per million (ppm) as the arsenic concentration in soils for the entire United States and 7.2 ppm as the average arsenic concentration in soils for the western U.S.(1) Background arsenic concentrations in Central Oklahoma soils range from 0.6 to 21 ppm.(2) The USGS reports an average lead concentration of 13 parts per million (ppm) in soils for central Oklahoma(2) and an average lead concentration of 18 ppm for the Western United States.(3) Pollution from historic lead and zinc smelters in Oklahoma left residues of lead, arsenic and cadmium in area soils. Contamination was also spread by using smelter debris as fill material, driveways and roads. These former smelters were primarily located in eastern Oklahoma. Some arsenic contamination above naturally occurring levels is also attributed to agricultural, energy and industrial practices. For example, arsenic-containing insecticides and herbicides were widely used on vegetables, fruits and field crops from the 1900s to around 1950. Coal combustion, wood preserving and smelting operations are known to be sources of arsenic contamination.(1) Lead was once commonly used in paint and in plumbing. Lead was an additive to gasoline for many years and has also been found in ceramics, mini-blinds and other products. Homes built before 1970 commonly have lead-based paint. Renovation activities and peeling or flaking paint can release lead inside the home.
    [Show full text]
  • Health Concerns of Heavy Metals (Pb; Cd; Hg) and Metalloids (As)
    Health concerns of the heavy metals and metalloids Chris Cooksey • Toxicity - acute and chronic • Arsenic • Mercury • Lead • Cadmium Toxicity - acute and chronic Acute - LD50 Trevan, J. W., 'The error of determination of toxicity', Proc. Royal Soc., 1927, 101B, 483-514 LD50 (rat, oral) mg/kg CdS 7080 NaCl 3000 As 763 HgCl 210 NaF 52 Tl2SO4 16 NaCN 6.4 HgCl2 1 Hodge and Sterner Scale (1943) Toxicity Commonly used term LD50 (rat, oral) Rating 1 Extremely Toxic <=1 2 Highly Toxic 1 - 50 3 Moderately Toxic 50 - 500 4 Slightly Toxic 500 - 5000 5 Practically Non-toxic 5000 - 15000 6 Relatively Harmless >15000 GHS - CLP LD50 Category <=5 1 Danger 5 - 50 2 Danger 50 - 300 3 Danger 300 - 2000 4 Warning Globally Harmonised System of Classification and Labelling and Packaging of Chemicals CLP-Regulation (EC) No 1272/2008 Toxicity - acute and chronic Chronic The long-term effect of sub-lethal exposure • Toxicity - acute and chronic • Arsenic • Mercury • Lead • Cadmium Arsenic • Pesticide o Inheritance powder • Taxidermy • Herbicide o Agent Blue • Pigments • Therapeutic uses Inorganic arsenic poisoning kills by allosteric inhibition of essential metabolic enzymes, leading to death from multi- system organ failure. Arsenicosis - chronic arsenic poisoning. Arsenic LD50 rat oral mg/kg 10000 1000 LD50 100 10 1 Arsine Arsenic acid Trimethylarsine Emerald green ArsenicArsenious trisulfide oxideSodium arsenite MethanearsonicDimethylarsinic acid acid Arsenic poisoning by volatile arsenic compounds from mouldy wall paper in damp rooms • Gmelin (1839) toxic mould gas • Selmi (1874) AsH3 • Basedow (1846) cacodyl oxide • Gosio (1893) alkyl arsine • Biginelli (1893) Et2AsH • Klason (1914) Et2AsO • Challenger (1933) Me3As • McBride & Wolfe (1971) Me2AsH or is it really true ? William R.
    [Show full text]
  • The Development of the Periodic Table and Its Consequences Citation: J
    Firenze University Press www.fupress.com/substantia The Development of the Periodic Table and its Consequences Citation: J. Emsley (2019) The Devel- opment of the Periodic Table and its Consequences. Substantia 3(2) Suppl. 5: 15-27. doi: 10.13128/Substantia-297 John Emsley Copyright: © 2019 J. Emsley. This is Alameda Lodge, 23a Alameda Road, Ampthill, MK45 2LA, UK an open access, peer-reviewed article E-mail: [email protected] published by Firenze University Press (http://www.fupress.com/substantia) and distributed under the terms of the Abstract. Chemistry is fortunate among the sciences in having an icon that is instant- Creative Commons Attribution License, ly recognisable around the world: the periodic table. The United Nations has deemed which permits unrestricted use, distri- 2019 to be the International Year of the Periodic Table, in commemoration of the 150th bution, and reproduction in any medi- anniversary of the first paper in which it appeared. That had been written by a Russian um, provided the original author and chemist, Dmitri Mendeleev, and was published in May 1869. Since then, there have source are credited. been many versions of the table, but one format has come to be the most widely used Data Availability Statement: All rel- and is to be seen everywhere. The route to this preferred form of the table makes an evant data are within the paper and its interesting story. Supporting Information files. Keywords. Periodic table, Mendeleev, Newlands, Deming, Seaborg. Competing Interests: The Author(s) declare(s) no conflict of interest. INTRODUCTION There are hundreds of periodic tables but the one that is widely repro- duced has the approval of the International Union of Pure and Applied Chemistry (IUPAC) and is shown in Fig.1.
    [Show full text]
  • The Place of Zinc, Cadmium, and Mercury in the Periodic Table
    Information • Textbooks • Media • Resources The Place of Zinc, Cadmium, and Mercury in the Periodic Table William B. Jensen Department of Chemistry, University of Cincinnati, Cincinnati, OH 45221-0172; [email protected] One of the few facts that I can remember from my un- a quarter of the more recent introductory inorganic texts. In dergraduate inorganic course was my instructor’s insistence all cases, the Zn group was incorrectly labeled as being a mem- that zinc, cadmium, and mercury should be classified as main- ber of the d block or transition block. Those introductory block elements rather than as transition-block or d-block el- inorganic texts that presented some sort of systematic survey ements. Though I have always assumed that the evidence for of descriptive chemistry usually contradicted this assignment this statement was unambiguous, I have also noticed the ap- in their later discussions of the chemistry of these elements. pearance over the last decade of an increasing number of gen- On the other hand, the surveys of descriptive chemistry found eral chemistry texts, inorganic texts, and advanced inorganic in most of the general chemistry texts were so superficial that monographs that either explicitly or implicitly contradict this the existence of this inconsistency seldom became explicit. assignment. The inorganic textbook by Cotton and In light of these trends, I thought it might be of interest Wilkinson, which has served as the American standard for to summarize the evidence relating to the proper placement nearly 40 years, has always been firm in its treatment of the of the Zn group within the periodic table.
    [Show full text]
  • United States Patent Office
    Patented Mar. 12, 1946 2,396.465 UNITED STATES PATENT OFFICE PREPARATION OF SODUMARSENTE Erroll Hay Karr, Tacoma, Wash, assignor to The Pennsylvania Salt Manufacturing Company, Philadelphia, Pa, a corporation of Pennsyl vania No Drawing. Application October 12, 1943, Serial No. 506,00 3 Claims. (C. 23-53) This invention relates to the production of metal arsenites from alkali metal hydroxide and high arsenic content water soluble, alkali metal arsenic trioxide without the necessity of using arsenites, and more particularly, it relates to an the alkali metal hydroxide in powder form. improved method of causing a controlled reac Another object of the invention is to provide tion between an alkali metal hydroxide and a cheap and easily performed process for the arsenic trioxide to obtain a granular product in preparation of alkali metal arsenites from con a one-step operation. centrated solutions of caustic alkali and pow It is known that solid sodium arsenite can be dered arsenic trioxide in standard mixing equip prepared by mixing together powdered Solid ment. caustic soda and arsenic oxide in a heap and O An additional object of the invention is to pro initiating the reaction by adding a small quan vide a process for obtaining alkali metal arsenites tity of water. Ullmann's Encyclopedia der Techn. in granular form from concentrated solutions of Chemie., volume I, page 588. This method will caustic alkali and powdered arsenic trioxide. yield a solid material but it is attended by sev A further object of the invention is to provide eral disadvantages. 5 a process for the preparation of granular alkali .
    [Show full text]
  • Removal of Heavy Metals from Aqueous Solution by Zeolite in Competitive Sorption System
    International Journal of Environmental Science and Development, Vol. 3, No. 4, August 2012 Removal of Heavy Metals from Aqueous Solution by Zeolite in Competitive Sorption System Sabry M. Shaheen, Aly S. Derbalah, and Farahat S. Moghanm rich volcanic rocks (tuff) with fresh water in playa lakes or Abstract—In this study, the sorption behaviour of natural by seawater [5]. (clinoptilolite) zeolites with respect to cadmium (Cd), copper The structures of zeolites consist of three-dimensional (Cu), nickel (Ni), lead (Pb) and zinc (Zn) has been studied in frameworks of SiO and AlO tetrahedra. The aluminum ion order to consider its application to purity metal finishing 4 4 wastewaters. The batch method has been employed, using is small enough to occupy the position in the center of the competitive sorption system with metal concentrations in tetrahedron of four oxygen atoms, and the isomorphous 4+ 3+ solution ranging from 50 to 300 mg/l. The percentage sorption replacement of Si by Al produces a negative charge in and distribution coefficients (Kd) were determined for the the lattice. The net negative charge is balanced by the sorption system as a function of metal concentration. In exchangeable cation (sodium, potassium, or calcium). These addition lability of the sorbed metals was estimated by DTPA cations are exchangeable with certain cations in solutions extraction following their sorption. The results showed that Freundlich model described satisfactorily sorption of all such as lead, cadmium, zinc, and manganese [6]. The fact metals. Zeolite sorbed around 32, 75, 28, 99, and 59 % of the that zeolite exchangeable ions are relatively innocuous added Cd, Cu, Ni, Pb and Zn metal concentrations (sodium, calcium, and potassium ions) makes them respectively.
    [Show full text]