How can I dissolve para chlorobenzoic acid (p-CBA) in water as it is insoluble in water. I want to use it as a probe of hydroxyl radicals in catalytic ozonation.
Thanks Waseem and Andersen. DMF increase Total organic carbon(TOC) so we can not use it. my experiment is related to catalytic ozonation for water treatment.
Creating a stock solution in water by increasing the pH with NaOH can work for this type of experiment.
If the high alkalinity of the stock solution affect the pH in the sample it is easy to make an acidic solution with the same acidity as the as the alkalinity of the p-CBA solution and add it after to maintain the pH in the treated samples.
Thnaks Dr Andersen. Definitely alkaline pH will affect the experiment. you mean first increase the pH by adding appropriate amount of NaOH till pcba is dissolved and then according add acid to neutralize it. But before adding the NaOH we are not sure what is the exact pH (natural pH) of the PCBA. i conduct my experiment at the natural pH of pollutants without adding any buffer. so adding base and then neutralizing it maybe work. please tell me your opinion?
I think you got it. I am talking about using two solutions. The first is p-PCA in solution made basic with NaOH. The second is a solution with the same normality of acid (H2SO4 or HCl etc.) as the concentration of base in the first solution. For an experiment I propose to add the same volume of the second solution immediately after the first. As the acidity and basicity match there will not be any effect on pH.
I propose to create the two solutions by weighing out calculated amounts of the chemicals. If high precision on the pH is needed then adjust the precision on the concentration of the acid solution after a test there e.g. 1 ml of both solutions is added to 1 L demineralised water which pH is measured (should be close to neutral, pH 7)
Real water usually always have some buffering in the form of bicarbonate and natural organic molecules so the pH effect in reality will be less than that is observed in the test.
Hi Shah,
What concentration of PCBA you are trying to make in water ? If it is very low concentration of ppm or ppb level you can use hot water .
thanks Mirajkar.it will be in between 20 -50 ppm.how much is the temp of hot water?
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