For the food industry, by the environmental impact of the biggest factor is water, while food processing and pollution of the water environment, to prevent and control water pollution must understand the type and content of pollutants and physical and chemical properties, etc., you need to analyze the water samples for testing. This experiment is mainly for students to understand the water pollution indicators, master the water part of the common physical and chemical indicators of the determination of methods and procedures.

Operation method

Measurement of suspended solids in water

Principle

The water sample was filtered and the solids retained on the filter paper were dried at 103-105°C to a constant amount to obtain the mass of suspended solids

Materials and Instruments

All Glass Microporous Membrane Filter Suction Filter Equipment

Move

1. Instruments

(1) All-glass microporous membrane filter: This book uses CNCA filter membrane with pore size of 0.45um, 60mm, or No.2 glass sand core funnel, or quantitative filter paper of medium psychology.

(2) suction filter equipment: suction filter bottle, vacuum pump or water jet.

2. Procedure

(1) Collection and storage of water samples

Collect a representative water sample of 500-1000 ml in a washed polyethylene bottle or a hard glass bottle with a tightly closed stopper. Floating or submerged inhomogeneous solid material does not belong to the suspended matter, should be removed from the water sample. Sampling should be measured as soon as possible after sampling, such as unconditional, should be stored in a refrigerator at 4 ℃, but not more than 7d at the longest, can not be added to any protective agent, in order to prevent the destruction of the distribution of substances in the solid-liquid equilibrium between.

3. Filter preparation

Place a piece of filter membrane (or filter paper washed with distilled water) in a weighing bottle, open the cap, and remove it after drying at 103-105°C for 30 min. Cool to room temperature in a desiccator, cap the bottle and weigh, repeat drying, cooling and weighing until the mass difference between the two weighings is less than 0.2mg.

4. Determination

Take 100ml of water sample with uniform oscillation (if necessary, the volume of water sample can be reduced or increased, so that it contains 10-100mg of suspended solids), filtered through a membrane (or filter paper), and then washed with 10ml of distilled water for 3 times each time.

Carefully remove the membrane containing suspended solids, put it into the original weighing bottle, transfer it to the oven at 103-105 ℃ for 1h, then transfer it to the desiccator, cool it down to room temperature, and weigh it. Repeat the drying, cooling and weighing process until the difference in mass between the two measurements is not more than 0.4mg.

5. Calculation of results


5. Determination of filtration with glass sand core funnel

If the filter with a glass funnel instead of the membrane, the method is the same as above, but do not use the weighing bottle, before and after filtration directly after the sand core funnel drying, cooling, weighing, until constant weight.

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