This article covers methods to resolve MySQL dump error 'illegal mix of collations'.
You should set both your table encoding and connection encoding to UTF-8:
ALTER TABLE keywords CHARACTER SET UTF8; -- run once
SET NAMES 'UTF8';
SET CHARACTER SET 'UTF8';
You can try to run SHOW CREATE TABLE my_table; and see which column was not converted or just fix incorrect character set on problematic column with query below (change varchar length and CHARSET and COLLATE according to your needs):
ALTER TABLE `my_table` CHANGE `my_column` `my_column` VARCHAR(10) CHARSET utf8
COLLATE utf8_general_ci NULL;