Can I use regular filter in order to separate uplink from downlink

For Example,
http://www.avx.com/docs/catalogs/lp0805.pdf
Is this filter, LP0805A0836AW for 824 - 849MHz can separate the downlink that is on 869 - 894MHz ?

And vice verse, How can a Low Pass Filter be used for 869 - 894MHZ if in lower frequency there is a disturbance of the uplink frequencies ?

theoretically you can, but you are going to need a better filter than that piece of junk if you expect channel separation.

There are two things to consider.
1. The out of band noise from the transmitter (at the receiving frequency) getting into the receiver.
2. The transmitter power overloading the receiver.
Both of these require filters with many elements. Also, the layout must be done to reduce coupling around the filters from input to output.