I solve a similar problem after uninstall and purge php.
# Stop service
sudo service apache2 stop
# Remove apache2 packages and dependencies:
sudo apt-get remove apache2;sudo apt-get autoremove --purge -y
# sudo apt-get purge apache2 apache2-utils apache2.2-bin apache2-common
# sudo apt-get autoremove --purge
# If you manually modified or installed stuff, apt might not remove it. Check what's left:
whereis apache2
# Use the answer to remove the directories
sudo rm -Rf /etc/apache2 /usr/lib/apache2 /usr/include/apache2
sudo rm -Rf /usr/sbin/apache2 /usr/lib/apache2 /etc/apache2 /usr/share/apache2 /usr/share/man/man8/apache2.8.gz