Adsorption Performance of Fe2O3-Modified Dolomite Composite (DFC) for Congo Red Removal

Printing and dyeing wastewater is known for its high color intensity, complex composition, and low biodegradability, making its treatment a significant challenge in environmental protection. Dolomite is a natural mineral with abundant reserves and can be effectively used as an adsorbent carrier. In this study, the dolomite loaded by Fe2O3 composites (DFC) was synthesized and systematically characterized using XRD, SEM, TEM, BET, XPS, and IR to evaluate its structural and surface properties. The adsorption performance of DFC on Congo Red (CR) was then investigated. The maximum adsorption amount of CR by DFC was 3790.06 mg⋅g−1, and the removal rate was still stable at 97% after five cycles of adsorption test, which demonstrated that DFC exhibited exceptional adsorption efficacy and regeneration capability. The loaded Fe3+ was beneficial to improve the adsorption effect on the DFC. In addition, to evaluate the type of adsorption, kinetic calculations were performed, which indicated that the Weber–Morris diffusion modeling study showed the adsorption behavior was influenced by the interplay of many diffusion mechanisms. The study offers an innovative method for the efficient utilization of dolomite in creating renewable adsorbent materials for dye wastewater remediation.