I don't know you or your group, so I couldn't say whether you should remove alignment or not. However, options are always good...
One thing you can do it not allow players to dictate their character alignments - they don't get to write it down on their character sheet. They behave however they wish. You, as DM, watch what they do, and assign alignment to them without telling them what it is. This works especially well if you've got high standards - so that one really has to be quite solidly Good before one earns that label.
One of course asks - can't they check what it is with Detect spells? Well, they can check each other. As written, it is reasonable to say that the caster of the spell is not within the area of effect of his own spell. And if they want to waste the spell power on that, well, that's their problem. Guess what happens when, through their greedy, combat loving, treasure seeking ways, one of them comes up evil?
As for your combat-focused, treasure-minded players - having a talk with them is probably in order. Trying another game might also help. Or trying another D&D campaign - with a low point buy character generation so that it is obvious that raw power isn't the way to go in the game.
One thing you can do it not allow players to dictate their character alignments - they don't get to write it down on their character sheet. They behave however they wish. You, as DM, watch what they do, and assign alignment to them without telling them what it is. This works especially well if you've got high standards - so that one really has to be quite solidly Good before one earns that label.
One of course asks - can't they check what it is with Detect spells? Well, they can check each other. As written, it is reasonable to say that the caster of the spell is not within the area of effect of his own spell. And if they want to waste the spell power on that, well, that's their problem. Guess what happens when, through their greedy, combat loving, treasure seeking ways, one of them comes up evil?

As for your combat-focused, treasure-minded players - having a talk with them is probably in order. Trying another game might also help. Or trying another D&D campaign - with a low point buy character generation so that it is obvious that raw power isn't the way to go in the game.