An economical and rapid type test pack for colorimetric determination of sulfides in a water body and a determination method are provided The test pack and the method are characterized in that: an integrated agent kit and a set of standard colorimetric cards are adopted to establish the convenient method, determination of a sample is achieved by following three simple steps, namely a step of performing a pre-chromogenic reaction, a step of performing a chromogenic reaction, and a step of comparing with the prefabricated standard colorimetric cards, and a determination range is 0-070 mg/L Only two agents are added in the whole operation process Operation is simple The agents are cheap and easily available The test pack and the method are capable of rapidly obtaining a determination result, free of use of any measurement instrument and low in determination cost, can be widely used in society after being developed into products, and further ensure water safety The test pack and the method fill the gap that only laboratory standard determination methods are provided for water sulfide determination at present while no rapid potable colorimetric determination method is provided

An economical and rapid type test pack for colorimetric determination of sulfides in a water body and a determination method

The invention relates to a determination method for chemical oxygen demand in water and wastewater. The determination method is characterized by comprising the following steps that 1, a H2SO4-Ag2SO4 solution is prepared; 2, multiple glass beads are added into a conical flask, a evenly mixed water sample is added, the H2SO4-Ag2SO4 solution is added, the conical flask is shaken while the H2SO4-Ag2SO4 solution is added, a AgCl precipitate is generated in the conical flask, an excessive amount of HgSO4 is added, a potassium dichromate solution is finally added, the conical flask is connected with a condenser pipe to start cooling water, heating reflux is performed, the cooling water is stopped after heating is stopped, the inner wall of the condenser pipe is washed in a water spraying mode, the conical flask is taken down, an o-phenanthroline indicating solution is added after the solution is cooled to the room temperature, the mixed solution is titrated to the end point with an ammonium ferrous sulfate standard solution, and the CODCr of the water sample is calculated. According to the determination method, the using amount of H2SO4 and Ag2SO4 is decreased, the using amount of the highly toxic matter HgSO4 is decreased by 70% or above, and the detection efficiency is improved.

Determination method for chemical oxygen demand in water and wastewater

The invention relates to a method for determining chemical oxygen demand (COD) of titanium dioxide production waste water, which belongs to the field of titanium dioxide production and comprises the steps of A neutralizing titanium dioxide waste water through alkali; B determining the chemical oxygen demand of neutralized titanium dioxide waste water through a potassium dichromate method, wherein the reaction time for heating return flow is 10-30 minutes; C enabling the titanium dioxide waste water with unqualified chemical oxygen demand to repeat the step of A. By means of the method for determining a value of the COD, under the premise of an accurate test value, the operation is simple and easy to implement and the analysis process is fast and effective. Therefore, the method can be widely applied to the detection of the COD of the titanium dioxide waste water.

Method for determining chemical oxygen demand (COD) of titanium dioxide production waste water

The invention relates to the field of water quality detection, in particular to a COD measuring method using less time in titration. The COD measuring method is used for detecting the COD of a water sample and comprises the following steps: adding reaction reagents into the water sample and adding excess oxidizing agents to conduct oxidizing reaction; adding excess reducing agents into the water sample after the oxidizing reaction and then the reduction reaction of reducing agents with the rest of oxidizing agents after the oxidizing reaction being conducted; adding oxidizing agents to titrate the rest of reducing agents after the reduction reaction with a first quick back slow speed and stopping titrating at the end point of titration; accumulating the quantity of the consumed oxidizing agents in the water sample according to the quantity of consumed oxidizing agents and reducing agents so as to accumulate the COD of the water sample. The COD measuring method has the advantages of using less time in titration.

COD measuring method

The invention relates to the field of water detection, and specifically relates to a dichromate titration method for measuring the COD (chemical oxygen demand) of water. The method is used to measureCOD of water through dichromate titration, the actual requirements of enterprises and related national standards are taken into account, moreover, the results are accurate, the process is simple, andthe pollution is small.

Dichromate titration method for measuring COD (chemical oxygen demand) of water

The invention discloses a method for measuring the chemical oxygen demand of waste water, which comprises the following steps: preparing standard solution of potassium dichromate, ferroin indicator solution, standard solution of ammonium ferrous sulfate, solution of sulfuric acid-silver sulfate and mercuric sulfate; diluting the mercuric sulfate in a water sample, adding the standard solution of potassium dichromate and a plurality of cleaned glass balls in a certain proportion; adding the solution of sulfuric acid-silver sulfate; heating the solution into an autoclave; after keeping the solution at a certain temperature and under a certain pressure for a period of time, adding water to continuously cool to room temperature; adding the ferroin indicator solution, performing titration through the standard solution of ammonium ferrous sulfate; recording the dosage of the standard solution of ammonium ferrous sulfate according to color changes; performing a blank experiment through distilled water according to the same operating steps; and recording the dosage of the standard solution of ammonium ferrous sulfate in blank titration. The method has the advantages of time conservation, and simple requirements on test conditions.

Jianfei Zhou

Papers

Method for measuring chemical oxygen demand of waste water