Is it permissible for the secretary of a commercial bids reception committee to accept promotional gifts (pens and notepads) from company representatives, knowing that this does not affect his integrity or cause him to show favoritism towards the giver?

If the gifts are offered to the company, there is no objection to accepting them. However, if they are for you personally, they should not be accepted, for fear that they might be a bribe or an attempt to sway you into dealing with the gifting companies over others.