Help, what is the difference between ppm and mg/l as units for oil in water?
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The safety instruments on site, such as hydrogen sulfide detectors, use ppm as the unit of measurement, while the actual alarm values specified in relevant regulations are given in mg/l; this can be converted using the molecular weight of hydrogen sulfide. However, the units for oil content in water vary; some instruments use ppm as the unit while others use mg/l. **The specified standard for discharging rainwater is 5 mg/l. How should this conversion between ppm and mg/l be carried out?** The oil quality in water is a complex mixture; can it be simply expressed as 1 ppm = 1 mg/l? It shouldn’t be possible, I guess. Some designers told me they are the same, while others said it’s impossible to compare the two, as one is a unit of content and the other is a unit of percentage value. I hope some expert can help me solve this problem; I would be extremely grateful!
You can ask Baidu if you have any questions. PPM is a percentage of volume concentration, with the unit being one part in million; mg/L represents mass concentration, that is, how many milligrams per liter. You should be able to convert it from there
As you mentioned, there is volume concentration and mass concentration; so what is the specific mass of oil in water? How exactly is the conversion done?
Use the molar mass of 5mg/oil = volume V; volume V/L equals the percentage. ppm stands for one part per million, and then the conversion can be made
For regular water quality samples, a concentration of 1 mg/L is roughly equivalent to a concentration of 1 ppm, as the density of water is approximately 1000 grams per liter. Therefore, 1 mg/L = 1 mg/1000 grams = 1 mg/1,000,000 mg = 1 ppm. Are there any difficulties or things that are hard to understand about this conversion? For water quality pollution testing, the oil content in water itself represents a measurement of the amount of oil (mixed hydrocarbons) present, that is, the total amount detected; the physicochemical properties of oil are relatively consistent, so there is nothing complicated about it.
PPM is a dimensionless way of expressing concentration; for liquids, it is the mass of the solute divided by the total mass of the solution, multiplied by 10-6 to give the value in ppm. For gases, it is the volume of the solute per unit volume of gas divided by unit volume, multiplied by 10-6 to determine the ppm value. The current international standard uses mg/L as the unit of measurement.
These two units are at the same level; in water, 1 ppm is simply equal to 1 mg/l
The density of water is indeed 1000 grams per liter, but when referring to oil in water, it pertains to the concentration of oil; the density of oil is certainly different from that of water, so it cannot be simply said to be roughly equivalent
So, for liquids, is there a difference between ppm and mg/l? Can they be considered equivalent?
Do you think a concentration of oil in the water of less than one ten-thousandth will have a significant impact on the water’s density? Is that the case? Discussing qualitative changes without a certain amount and accumulation is unobjective; in other words, the level of understanding is not on the same level.