Adsorption is a low-energy and easy-to-perform technique that can directly remove pollutants from water. However, owing to material limitations in terms of the adsorption capacity, efficiency, cost, and pollutant type, the application of this method is challenging in high-sulfate coal mine drainage (CMD) purification. Based on a coal mine in Erdos (China) with high-sulfate CMD, a multifunctional Ba-modified geopolymer foam (Ba/GPF) adsorbent was developed, and its ion adsorption efficiency was verified, along with its application performance in a practical situation. The excellent pore structure of Ba/GPF adsorbent allowed the dynamic removal of SO42− (>86%), Ca2+ and Mg2+ (>99%), Na+ (>50%), K+ (>77%), TDS (>60%), and suspended solids (>97%) from actual CMD. Furthermore, the addition of Na2CO3 combined with ultrasonic and acid treatment effectively removed the BaSO4 crystals to recover the regeneration capacity of Ba/GPF. Importantly, the adsorption capacity decreased by only 25.9% after 8 regeneration cycles. Subsequently, Ba/GPF was applied on a small scale to an actual coal mine, and its effectiveness was verified. This adsorbent can therefore be considered applicable in energy-free working conditions, such as those found in underground producing mine goafs. Overall, the Ba/GPF shows promising potential for the efficient and flexible treatment of high-sulfate wastewater.