Method and apparatus for rapid determination of water body sediment AVS and SEM

Abstract

The invention discloses a method and an apparatus for rapid determination of water body sediments AVS and SEM. The apparatus comprises a nitrogen cylinder (1), gas-washing bottles (2), reaction bottles (6) and gas absorption bottles (11). A gas-washing bottle (2), a reaction bottle (6) and a gas absorption bottle (11) that are successively installed in series by a pipeline form a branch; a plurality of branches in parallel connection are connected to the nitrogen cylinder; a gas flowmeter (2) is arranged in front of each gas-washing bottle (2) in each branch, and a gas flowmeter (2) is arranged after the nitrogen cylinder in a main road; the reaction bottles are sealed by rubber plug (9) coated with glass cement, and the rubber plug are provided with acid inlet apparatuses. According to the method, hydrogen sulfide gas generated from the reaction is extracted by high purity nitrogen and absorbed by a lye; and the parallel connection accelerates a measure speed; and links of sample introduction, reaction and absorption are reinforced to increase speed and accuracy. On the premise of measure precision guarantee, the AVS determination method of the invention can as shortens time effectively and achieves good effects.

Description

technical field [0001] The invention belongs to the technical field of measurement (environmental monitoring), and in particular relates to a method and device for quickly measuring sediment AVS and SEM. Background technique [0002] The biological toxicity of heavy metals deposited in water bodies is one of the hot issues in the current environmental field. The core and difficulty is to quantify the ecological hazards of deposited heavy metals, and then establish relevant models for easy application in environmental management practices. The AVS / SEM method is an effective tool in this regard. AVS is defined as the ability to be 1mol L -1 Sulfides extracted with cold hydrochloric acid; SEM refers to metals extracted simultaneously during the extraction of AVS with hydrochloric acid. The theoretical basis of AVS / SEM is the sulfophilicity of heavy metals, and the two are easy to form stable metal sulfides, thereby reducing the biological toxicity of heavy metals: AVS represe...

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Problems solved by technology

[0006] There are many problems in the actual operation of these two methods, mainly as follows: First, the reaction time is long (a sample needs more than 2 hours), because the preservation of AVS samples is very difficult (and theoretically, the preservation time cannot exceed 2 weeks) , so it is impossible to measure a large number of samples, making it almost impossible to apply AVS to a wide range of ecological risk assessments; second, the lack of effective sampling methods affects the speed and accuracy. The current method is not suitable for sediment samples and acid A large amount of air is brought into during the adding process of the reactor, so that the measured value of AVS is lower than the actual value; the third is the lack of a good sealing method: in order to prevent the sulfur in the rubber stopper from affecting the measured value of AVS, the current method adopts cork as the closed way of the reactor. However, cork stoppers are not as good as rubber stoppers in terms of airtightness, and cork stoppers are difficult to perform operations such as punching. Since at least 3 holes must be punched in the reactor, it is difficult to do it in actual operation.

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