'approximately 2 months' is correct and usable in written English.
You can use it when you are approximating a length of time. For example, "I will need approximately 2 months to complete this project."
The highest concentration of hexazinone (16 μg L−1) was recorded in stream water during a 60-mm rainfall event approximately 2 months (68 DAT) after herbicide application.
The effect vanishes after approximately 2 months.
The full-scale anammox reactor could be started up in approximately 2 months.
All participants were administered the Driver Behaviour Questionnaire before and approximately 2 months after simulator testing.
Information for 364 eligible participants was primarily collected through telephone interview, approximately 2 months after injury.
One patient died, and the other survived after approximately 2 months in hospital [10].
Darters were moved in late March 2001 at the beginning of their reproductive season, which continues for approximately 2 months.
In contrast to the experimental testing which occurred over approximately 2 months, computational wear predictions required only 2 h.
And this length chain PEG-modified SWCNTs had near-complete clearance from the main organs in approximately 2 months.
Approximately 2 months after discharge, the patient reported progressive lower back pain associated with left leg weakness and numbness.
The stability of the nanoparticles was monitored for approximately 2 months to examine the pH effect on nanoparticle stability.
