ASTM D6696-14
(Guide)Standard Guide for Understanding Cyanide Species
Standard Guide for Understanding Cyanide Species
SIGNIFICANCE AND USE
4.1 This guide provides standard terminology for use in identifying and describing the different chemical forms of cyanide. The complex nature of cyanide chemistry, existence of numerous distinct chemical forms as well as the various regulatory distinctions that may be made can lead to confusion in technical discussions on cyanide and in the selection of appropriate methods for its analysis. This guide is intended to provide clarification and a common framework of terms and definitions to facilitate discussions and referencing different cyanide chemical species and groups of cyanide compounds.
4.2 The use of such common terminology is particularly important from an environmental perspective because certain forms of cyanide are considered to be toxic. Therefore, their release into the environment is regulated by federal and state agencies. Thus a general understanding of cyanide chemistry and species definitions is needed for proper wastewater management and testing.
SCOPE
1.1 This guide defines guidance based on a consensus of viewpoints for interpretation of test results to identify various chemical forms of cyanide. It is intended to provide a general understanding of the chemical nature of distinct cyanide species as related to chemical analysis and environmental fate and transport.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
General Information
Relations
Buy Standard
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D6696 − 14
StandardGuide for
1
Understanding Cyanide Species
This standard is issued under the fixed designation D6696; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* definitions to facilitate discussions and referencing different
cyanide chemical species and groups of cyanide compounds.
1.1 This guide defines guidance based on a consensus of
viewpoints for interpretation of test results to identify various 4.2 The use of such common terminology is particularly
chemical forms of cyanide. It is intended to provide a general
important from an environmental perspective because certain
understanding of the chemical nature of distinct cyanide forms of cyanide are considered to be toxic. Therefore, their
species as related to chemical analysis and environmental fate
release into the environment is regulated by federal and state
and transport. agencies. Thus a general understanding of cyanide chemistry
and species definitions is needed for proper wastewater man-
1.2 The values stated in SI units are to be regarded as
agement and testing.
standard. No other units of measurement are included in this
standard.
5. Cyanide Species Terms and Definitions
2. Referenced Documents
5.1 Chemistry Related Terms and Definitions:
2
5.1.1 Cyanide Ion—The term used to describe a negatively
2.1 ASTM Standards:
charged ion comprised of one carbon atom and one nitrogen
D1129 Terminology Relating to Water
-
atom triply bonded to each other (C≡N ). The cyanide ion is
D1426 Test Methods for Ammonia Nitrogen In Water
reactive and readily forms neutral compounds or anionic
D3590 Test Methods for Total Kjeldahl Nitrogen in Water
complexes with most metals.
D7237 Test Method for Free Cyanide with Flow Injection
5.1.2 Free Cyanide—The form of cyanide that is bioavail-
Analysis (FIA) Utilizing Gas Diffusion Separation and
Amperometric Detection able and known for its toxic effect on organisms (1). Free
cyanide refers to the sum of molecular hydrogen cyanide
-
3. Terminology
(HCN)andcyanideion(CN ).Hydrogencyanideisacolorless,
poisonous gas having an odor of bitter almonds (mp = -13.4°C,
3.1 Definitions—For a definition of terms used in this guide,
bp = 25.6°C). It is readily soluble in water existing as HCN or
refer to Terminology D1129.
-
CN , or both, depending on the pH conditions (pK = 9.36).At
a
a pH of 7 or less in water, free cyanide is present entirely as
4. Significance and Use
HCN; the opposite is true at pH 11 or greater. Because of its
4.1 This guide provides standard terminology for use in
toxicity, free cyanide is regulated in environmental wastewater
identifying and describing the different chemical forms of
discharges.
cyanide. The complex nature of cyanide chemistry, existence
5.1.2.1 In Test Method D7237, sum of the free cyanide
of numerous distinct chemical forms as well as the various
-
(HCN and CN ) and cyanide bound in the metal-cyanide
regulatory distinctions that may be made can lead to confusion
complexes that are easily dissociated into free cyanide under
in technical discussions on cyanide and in the selection of
thetestconditionsdescribedinTestMethodD7237atpH6and
appropriate methods for its analysis. This guide is intended to
room temperature.
provide clarification and a common framework of terms and
5.1.3 Aquatic Free Cyanide—In Test Method D7237, free
cyanidemeasuredwhenthebufferortemperatureisadjustedto
mimic the receiving water environment.
1
This guide is under the jurisdiction of ASTM Committee D19 on Water and is
the direct responsibility of Subcommittee D19.06 on Methods for Analysis for 5.1.4 Simple Cyanide—A neutral compound comprised of
Organic Substances in Water.
an alkali metal, alkaline earth metal or ammonium cation
Current edition approved Jan. 1, 2014. Published January 2014. Originally
bound to cyanide. Simple cyanides are so named because of
approved in 2001. Last previous edition approved in 2010 as D6696 – 10. DOI:
their structural simplicity and their ability to completely
10.1520/D6696-14.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or dissolve and dissociate in water to produce free cyanide and a
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
cation according to the following reaction:
Standards volume information, refer to the standard’s Document Summary page on
1 2
the ASTM website. ACN→A 1CN (1)
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D6696 − 10 D6696 − 14
Standard Guide for
1
Understanding Cyanide Species
This standard is issued under the fixed designation D6696; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope*
1.1 This guide defines standard terminology used for the classification of the guidance based on a consensus of viewpoints for
interpretation of test results to identify various chemical forms of cyanide. It is intended to provide a general understanding of the
chemical nature of distinct cyanide species as related to chemical analysis and environmental fate and transport.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
2. Referenced Documents
2
2.1 ASTM Standards:
D1129 Terminology Relating to Water
D1426 Test Methods for Ammonia Nitrogen In Water
D3590 Test Methods for Total Kjeldahl Nitrogen in Water
D7237 Test Method for Free Cyanide with Flow Injection Analysis (FIA) Utilizing Gas Diffusion Separation and Amperometric
Detection
3. Terminology
3.1 Definitions—For a definition of terms used in this guide, refer to Terminology D1129.
4. Significance and Use
4.1 This guide provides standard terminology for use in identifying and describing the different chemical forms of cyanide. The
complex nature of cyanide chemistry, existence of numerous distinct chemical forms as well as the various regulatory distinctions
that may be made can lead to confusion in technical discussions on cyanide and in the selection of appropriate methods for its
analysis. This guide is intended to provide clarification and a common framework of terms and definitions to facilitate discussions
and referencing different cyanide chemical species and groups of cyanide compounds.
4.2 The use of such common terminology is particularly important from an environmental perspective because certain forms
of cyanide are considered to be toxic. Therefore, their release into the environment is regulated by federal and state agencies. Thus
a general understanding of cyanide chemistry and species definitions is needed for proper wastewater management and testing.
5. Cyanide Species Terms and Definitions
5.1 Chemistry Related Terms and Definitions:
5.1.1 Cyanide Ion—The term used to describe a negatively charged ion comprised of one carbon atom and one nitrogen atom
-
triply bonded to each other (C≡N ). The cyanide ion is reactive and readily forms neutral compounds or anionic complexes with
most metals.
5.1.2 Free Cyanide—The form of cyanide that is bioavailable and known for its toxic effect on organisms (1). Free cyanide
-
refers to the sum of molecular hydrogen cyanide (HCN) and cyanide ion (CN ). Hydrogen cyanide is a colorless, poisonous gas
-
having an odor of bitter almonds (mp = -13.4°C, bp = 25.6°C). It is readily soluble in water existing as HCN or CN , or both,
depending on the pH conditions (pK = 9.36). At a pH of 7 or less in water, free cyanide is present entirely as HCN; the opposite
a
is true at pH 11 or greater. Because of its toxicity, free cyanide is regulated in environmental wastewater discharges.
1
This guide is under the jurisdiction of ASTM Committee D19 on Water and is the direct responsibility of Subcommittee D19.06 on Methods for Analysis for Organic
Substances in Water.
Current edition approved June 1, 2010Jan. 1, 2014. Published July 2010January 2014. Originally approved in 2001. Last previous edition approved in 20052010 as
ε1
D6696 – 05D6696 – 10. . DOI: 10.1520/D6696-10.10.1520/D6696-14.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
D6696 − 14
-
5.1.2.1 In Test Method D7237, sum of the free cyanide (HCN and CN ) and cyanide bound in the metal-cyanide complexes that
are easily dissociated into free cyanide under the test conditions described in Test Method D7237 at pH 6 and room temperature.
5.1.3 Aquatic Free Cyanide—In Test Method D72
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.