Op Amp as a simple switch
You are using an op-amp as a comparator, not ideal but not the end of the world in many applications. Your circuit could work with the proper op-amp. You need one that can reach ground when its power supply is tied to ground. This is what most single-supply op-amps do, particularly if they have rail-to-rail outputs. 

But if you are going to actually buy the parts (not just pick them up from a drawer) go for a real comparator.