Method for extracting microplastics in dewatered sludge and lab-scale test device

A dewatered sludge and extraction method technology, which is applied in the direction of measuring devices, plastic recycling, and analysis materials, can solve the problems of secondary environmental pollution, high cost, and inapplicable extraction of microplastic particles in the dewatered sludge system, achieving recycling The effect of high efficiency, low cost, and small sample demand

Inactive Publication Date: 2018-08-07
SHANGHAI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Since the sludge system is different from sediment and surface water, the content of organic impurities in sludge is much greater than that in sediment, and most microplastics in sludge have a relatively light density. Using a single saturated NaCl solution to density-separate microplastics has been used. Can effectively extract, add NaI, ZnCl 2 Flotation separation of solute solution not only costs high, but also caus...

Method used

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  • Method for extracting microplastics in dewatered sludge and lab-scale test device
  • Method for extracting microplastics in dewatered sludge and lab-scale test device
  • Method for extracting microplastics in dewatered sludge and lab-scale test device

Examples

Experimental program
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Embodiment 1

[0029] In this example, see Figure 1~4 , sampling dewatered sludge samples from 10 sewage plants, using the method of extracting microplastics in dewatered sludge, including the following steps:

[0030] a. Freeze-dry and homogenize the dewatered sludge sample from a sewage plant to obtain raw materials to be treated. The freeze-drying temperature is -20°C, and the freeze-drying time is 24 hours;

[0031] b. Mining density is 1.2g / cm 3 The sodium chloride solution is used as a density solution for subsequent use, get 20g of the raw material to be treated obtained in the step a in the suction filter bottle, add the sodium chloride solution to the suction filter bottle, and mix the raw material to be treated with the sodium chloride solution Form a mixed solution, and use a magnetic stirrer to control the stirring rate to 400r / min to fully stir the suspension for 1 hour until the solution is completely suspended to obtain a mixed suspension;

[0032] c. Stand still the suspen...

Embodiment 2

[0044] This embodiment is basically the same as Embodiment 1, especially in that:

[0045] In this embodiment, a method for extracting microplastics from dewatered sludge includes the following steps:

[0046] a. This step is the same as in Embodiment 1;

[0047] B. adopt saturated sodium chloride solution as the density solution for subsequent use, get 10g of the raw material to be treated obtained in said step a in the suction filter bottle, add saturated sodium chloride solution to the suction filter bottle, make the raw material to be treated and saturated Mix the sodium chloride solution to form a mixed solution, and use a magnetic stirrer to control the stirring rate to 400r / min to fully stir the suspension for 1h until the solution is completely suspended to obtain a uniform suspension;

[0048] c. Stand still the suspension prepared in the step b, and control the standing time so that the suspension is completely stratified into a sedimentation layer and a non-sedimen...

Embodiment 3

[0055] This embodiment is basically the same as the previous embodiment, and the special features are:

[0056] In this example, commercial plastic polyethylene of 30 mesh and 200 mesh, polypropylene of 20 mesh and 200 mesh, polystyrene of 40 mesh and 200 mesh were purchased, as microplastic samples, and according to this embodiment—using microplastics in dewatered sludge The extraction method of plastics is tested for the recovery rate of microplastic particles. The sludge after extracting clean microplastic particles was taken as the experimental medium, and the microplastic sample was mixed with the sludge after clean microplastic particles as the sludge experiment material in the experiment of this embodiment, and the simulation experiment was carried out. Each size of commercial plastic Three parallel experiments were carried out, and the recovery rate was 66.7-97.8%, as shown in Table 2 below.

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Abstract

The invention discloses a method and device for extracting microplastics in dewatered sludge. The method comprises the following steps: carrying out freeze-drying homogenization on the dewatered sludge, then adding a density solution and stirring to obtain turbid liquid, and standing until the turbid liquid is layered completely; transferring microplastics particles which float in a non-precipitating layer to a filter membrane under the effect of an air pump, and rapidly collecting the microplastics particles; continuously adding the density solution into a filter flask and keeping the solution parallel and level to a suction nozzle, and then washing a pipe for several times to transfer the microplastics particles adhered to the wall of the pipe to the filter membrane; adding the intercepted microplastics particles into a hydrogen peroxide solution, and carrying out shock reaction to remove organic matter impurities in the sludge; and drying to remove residual liquid, and cooling to obtain the final microplastics particles. The method has the advantages that the microplastics particles in the dewatered sludge are extracted on the basis of a density separation principle, and the method is rapid and simple to operate, low in sample demand quantity, high in microplastics particle recycling rate, good in reproducibility, high in practicality and widely applicable to ecological environment risk researches of the microplastics in the dewatered sludge.

Description

technical field [0001] The invention relates to a method for extracting and analyzing microplastics in sludge, in particular to a method for extracting microplastic particles in sludge by using a density sorting method, which is applied to the technical field of solid waste sludge treatment. Background technique [0002] As the amount of plastic continues to increase, and its own refractory characteristics, the environmental pollution and risks caused by plastic continue to increase. Microplastics refer to plastic particles with a diameter of less than 5 mm that enter the ecological environment through various channels. According to their sources, they can be divided into primary microplastics and secondary microplastics. Nascent microplastics are mainly microscopic-scale plastics produced in factories and are found in many cosmetic products, used in facial scrubs or airblast media, and plastic debris generated during the washing process of clothing. Secondary microplastic...

Claims

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Application Information

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IPC IPC(8): G01N33/44B29B17/02
CPCB29B17/02G01N33/442Y02W30/62
Inventor 李小伟陈璐蓓梅庆庆张鸿元丁国际
Owner SHANGHAI UNIV
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