Remove Emoji Support

If you want to remove the Emoji support, use the snippet below:

function wpkb_remove_emoji() {
    // Remove emojis from comment feed and RSS
    remove_filter( 'the_content_feed', 'wp_staticize_emoji' );
    remove_filter( 'comment_text_rss', 'wp_staticize_emoji' );

    // Remove emojis from emails
    remove_filter( 'wp_mail', 'wp_staticize_emoji_for_email' );

    // Remove emojis from the head tag
    remove_action( 'wp_head', 'print_emoji_detection_script', 7 );

    // Remove emojis from print related styling
    remove_action( 'wp_print_styles', 'print_emoji_styles' );

    // Remove emojis from admin area
    remove_action( 'admin_print_scripts', 'print_emoji_detection_script' );
    remove_action( 'admin_print_styles', 'print_emoji_styles' );
}

add_action( 'init', 'wpkb_remove_emoji' );

Another solution might be the plugin Disable Emojis. Install the plugin and the Emoji support is removed.