Okay, let's sum this up.
In Illinois BOTH parents need to give sworn consent in front of the county clerk. In addition, the days of a teenager crossing state lines to get married without parental consent are over; there is now NO state where a minor can marry without parental consent, consent of a judge, or both. So getting married isn't happening.
You mentioned emancipation. That's also a no-starter, since Illinois law specifically requires that the minor be living apart from her parents BEFORE she can apply for emancipation, and also requires that the emancipation be unopposed by her parents. (The law also addresses running away from home as not being helpful to emancipation so don't even go down that road.) So emancipation isn't happening.
You've already reported the alleged abuse to the authorities, and they either are not finding it or are not finding it to the extent that they feel the need to take action.
Illinois WILL return runaway children under 18 to their parents. If you assist her in a runaway situation, you are committing a crime (since she is over 17 it is a misdemeanor instead of a felony, but since she is under 18 it is still a crime) for which you can be criminally charged.
Running a bit low on solutions, here. How about you try waiting until she's of legal age to leave home?