How to disconnect an unwanted Wi-Fi user, using my iPhone 4?

I have a home Wi-Fi network that I share with my family but I use the Wi-Fi for my iPhone but I'd like to know of theirs a way to disconnect unwanted Wi-Fi users with my iPhone 4. The reason their unwanted is because their usually my brothers friends that come over and use my Wi-Fi but since I don't have a computer and I do almost everything off my phone I'm curiouser to know if theirs an app of some sort or a process I can use to kick off my brothers friends from my Wi-Fi. Their using up a lot of bandwidth and lagging my Internet speed. If possible on android I'd like to know the app or process on doing it as well.

I'm not sure if it is possible to do that. However maybe if you login to your router, you can see the list of clients connected and block them by their mac address of their device. This way if they try to connect to your Wi-Fi, it won't allow them because the actual device is banned from the router.

Your router usually will have an allow MAC list. Add family devices and others will not be able to connect.