Is it permissible to combine prayers at home upon returning, due to the difficulty of purifying oneself from prostatic secretions, which may be semen, while outside the home?

It is not permissible to delay prayers beyond their appointed times or to combine them upon returning home. Being at the university or outside the house does not permit this. The obligation is to perform each prayer at its designated time, and one can purify oneself from secretions in the university restrooms. If the secretions reach the level of سلس ( سلس البول - urinary incontinence or سلس الريح - constant passing of gas, generally meaning a continuous discharge that is difficult to control), then it is permissible to combine Dhuhr and Asr, as well as Maghrib and Isha. However, combining all prayers is not permissible.