The solubility of bisphenol A is higher than 30 mg/L so you properly just experience slow dissolution. Ultrasonication can help.

If you need to dissolve higher concentrations than the "regular" solubility of about 100 mg/L it helps to bring the pH up to around 10. 

The addition of a few percent of MeOH could probably help, especially when added to a suspension of 100-200 ppm Bisphenol A in water. If MeOH disturbs you should obviously remove it by some means (distillation?). By the literature at least about 120 ppm bisphenol A should dissolve at 25 C. You can try to heat up a saturated solution and filtering it after cooling back. You could also try ultrasonic mixers or mildly alkaline solutions (in case a little salt content is not disturbing, for example adding an equiv. amount of bicarbonate to a 100-200 ppm solution and neutralizing it back to pH 4-5.)

I agree with Dr. Imre Tóth. BPA dissolves in water-alcohol mixture. The alcohol as, methanol or ethanol, could be just 10% & upon warming the solvent mixture to dissolve good amount of BPA , the alcohol's % will decrease may be reaching 1 %. This is a "trick" to dissolve BPA.

If using another solvent is "allowed", then I suggest  ACETONITRILE.

• Thanks to all, but sine my goal is AOP treatment of BPA as an typical organic pollutant , It is preferred to add no organic chemicals to the media. I expected BPA should be dissolved in water in short time. Therefore I will use US waves and alkaline and biarbonate as well as let mixing proceed for 24 h.

Be careful with carbonate and bicarbonate together with AOP treatment. Both ions scavenge hydroxy radicals so the AOP becomes less effective.

Methanol and ethanol also disturbe AOP.

I suggest ultrasonification or increase pH with strong base, as soon BPA is dissolved adjust back to neutral with strong acid. 

BPA has moderately high solubility in water about 120 ppm at 25oC. You could try to adjust pH above 9.73 (pKa) with ultrasonication to dissolve and check the temperature.

By dissolving it in 5% ethanol then complete the distilled water

Ethanol interferes with AOP just like methanol.

1 mM BPA can be dissolved in DI water at 40°C in hotplate with magnetic stirring for 24 hours.

I tried ultrasonication with heating at the same time 

@ Sam Manz...

does Heating affect BPA?

Even I am experiencing problem with solubility of BPA..It is soluble in ethanol or dmso..but moment you make dilutions in aqueous phase..its recrystallize. .

I want to treat Cells with BPA ..so BPA treatment should be in media...

pls suggest.

The solubility of BPA is about 100 mg/L and acute effects to cells are generally observed at 1-10 mg/L. I think you are treating with a too high concentration.

not dissolve in methanol

What is the solubility of BFA in Epichlorohydrin or any other organic solvents?