Industrial dye-contaminated wastewater remains a major environmental challenge, while many conventional adsorbents exhibit selectivity toward either cationic or anionic dyes, limiting their practical applicability. This study developed a PAC-modified bentonite composite to improve its removal capability toward dyes with different ionic characteristics. The PAC-modified bentonite was synthesized through microwave-assisted impregnation using 1% (w/v) PAC at 1000 W for 10 min and characterized using FTIR, XRD, BET, and pHzc analyses. FTIR showed changes in the Al–OH-related region after PAC treatment, while XRD indicated that the main crystalline structure of bentonite was retained. These changes suggest that the treatment affected the surface environment of bentonite, although PAC incorporation could not be conclusively confirmed from the available characterization data. Adsorption experiments were conducted using methylene blue (MB), methyl orange (MO), and congo red (CR) as representative cationic and anionic dyes. Rapid dye uptake was observed, with relatively small changes in adsorption capacity after 30 min. High removal efficiencies were achieved for all dyes, exceeding 90% for MB and CR and 80% for MO under the investigated conditions. The improved performance was associated with changes in surface properties following PAC modification, particularly toward anionic dyes. These findings demonstrate that microwave-assisted PAC-modified bentonite is an effective composite material for the removal of both cationic and anionic dyes.