In this work, a costeffective and ecofriendly calciumdoped alphaFe2O3 (CaFe2O3) with abundant oxygen vacancies was fabricated using a scalable precipitationcalcination method to activate peroxymonosulfate (PMS) for wastewater purification. Density functional theory calculations revealed that the incorporation of Ca2 into the alphaFe2O3 structure enhances the electron transfer from alphaFe2O3 to PMS, facilitating the activation of PMS. The degradation of Rhodamine B by 5%CaFe2O3 proceeded with a reaction constant 8 times higher than that of pristine alphaFe2O3. This can be attributed to the increased generation of O1(2) and O2(center dot), increased specific surface area and enhanced electrical conductivity. The applicability of the 5%CaFe2O3PMS system was investigated including its operating parameters and stability, and the intermediates involved in the reaction were identified. The 5%CaFe2O3PMS system exhibited excellent degradation efficiency in natural water samples. This work opens up new perspectives for designing highly efficient catalysts and renders iron oxides potential candidates for environmental remediation.