Saline Remanence Test Composition for Safe Chloride Detection

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Solution Overview

Problem

Current methods for measuring chloride ions on roadways, such as the Mohr, Charpentier-Volhard, Fajan, Vogel, and gravimetric methods, utilize harmful substances like chromate, thiocyanate derivatives, and mercury, posing health and environmental risks to operators, and are not suitable for direct application on road surfaces.

Innovation Solution

A composition with a specific water/alcohol ratio of 2:3, containing 1-5 mg/ml of silver nitrate and more than 2 mg/ml of 2',7'-dichlorofluorescein, along with 20-40% glycerol, is used for semi-quantitative measurement of chloride ions, allowing easy reading of results directly on the road surface without using hazardous substances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional chloride detection methods (Mohr, Charpentier-Volhard, Fajan, Vogel) are used, then chloride ion measurement can be performed, but harmful substances (chromate, thiocyanate derivatives, mercury) are introduced posing health and environmental risks

Engineering Contradiction:
Improvechloride ion measurement accuracyVSAvoidhealth and environmental risks from harmful substances
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent removes harmful substances (chromate, thiocyanate, mercury) from the detection system entirely. The new composition uses only safe components: silver nitrate, 2',7'-dichlorofluorescein, alcohol, and water, eliminating the carcinogenic and toxic elements while preserving the chloride detection function through a different chemical mechanism.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces 2',7'-dichlorofluorescein as an intermediary substance that mediates the detection reaction between silver ions and chloride ions. This intermediary provides a safe, visible color change mechanism (forming a red complex) that replaces the harmful indicator systems while achieving the same measurement objective.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If traditional laboratory-based titration methods are used, then precise chloride quantification is achieved, but the methods are complex and not suitable for direct road surface application

Engineering Contradiction:
Improvechloride concentration determination accuracyVSAvoidsimplicity of direct road surface testing
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent merges the sample collection and analysis steps into a single direct application process. The composition is applied directly to the road surface, allowing the pavement itself to serve as the sample container, eliminating the need for separate sampling, filtration, and laboratory preparation steps required by traditional methods.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent uses a highly visible color change mechanism where 2',7'-dichlorofluorescein forms a red complex with silver-chloride precipitates. This intense color change provides clear visual endpoints that can be easily observed on the road surface without sophisticated instrumentation, making the process as simple as visual inspection while maintaining quantitative accuracy.

Inventive Principle:
Principle #32Color changes

3Ease of operation

If chromate-based indicators are used in Mohr's method, then chloride titration can be performed, but the chromate salts are carcinogenic, mutagenic, and reprotoxic requiring special handling

Engineering Contradiction:
Improveoperator handling convenienceVSAvoidcarcinogenic, mutagenic, and reprotoxic properties of chromate
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The patent converts the potentially harmful silver nitrate (which can form toxic silver compounds) into a beneficial system by using it in controlled, low concentrations with safe organic indicators. The silver ions are used precisely to detect chloride while the organic dye system provides safety benefits by being non-toxic and environmentally friendly, transforming a potentially hazardous inorganic system into a safe hybrid system.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This composition improves the quality of coloring, enabling easy and safe measurement of chloride ions on roadways, ensuring effective salinity persistence testing without exposing operators to harmful chemicals and allowing for precise determination of chloride levels for different temperature protection levels.

Implementation Method 1

The principle of this methodology is that chloride ions react with mercury(II) thiocyanate to produce minimally dissociated mercury(II) chloride

Methodology Applied
Scientific EffectPrecipitation: Precipitation

Implementation Method 2

The excess silver nitrate present is then determined by a titrated solution of ammonium sulfocyanide in the presence of ferric alum, as a color indicator. The solution then turns a reddish-orange color due to the complexation of Fe3+ ions with SCN− ions to give [Fe(SCN)]2+

Methodology Applied
Scientific EffectComplexation:

Implementation Method 3

The end of the reaction is indicated by the appearance of the characteristic red color of silver chromate

Methodology Applied
Scientific EffectColor change:

Implementation Method 4

A composition for the detection of chloride ions on the surface of a pavement, notable in that it comprises a water/alcohol ratio of between 2 and 3, between 1 and 5 mg/ml of silver nitrate, and more than 2 mg/ml of 2',7'-dichlorofluorescein

Methodology Applied
Scientific EffectSolvation: Solvation

Data Source

PatentEP3299808B1Saline remanence test
Publication Date: 2022.03.09 FILAB

AI summary

The present invention relates to the field of pavement treatment. More particularly, the present invention relates to compositions, assemblies of parts, methods, and uses for measuring the quantity of chloride ions on the surface of a pavement. The present invention relates in particular to a composition for detecting chloride ions on the surface of a pavement, characterized in that it comprises a water/alcohol ratio of between 2 and 3, between 20 and 40% glycerol, between 1 and 5 mg/ml of silver nitrate, and more than 2 mg/ml of 2',7'-dichlorofluorescein.