Multifunctional magnetic MgMn-oxide composite for efficient purification of Cd2+ and paracetamol pollution: Synergetic effect and stability

Abstract

A multifunctional magnetic composite (0.3Ma-MgMnLDO-a) with the function of Cd2+ adsorption and paracetamol (PAM) degradation was successfully fabricated. Surface morphology showed that Fe3O4 agglomeration was overcome on composite. The composite had high specific surface area of 105.32 m2 g−1 and saturation magnetization of 40 emu∙g-1. 0.3Ma-MgMnLDO-a could reach Cd2+ adsorption equilibrium within 5 min with 99 % removal rate. The maximum adsorption capacity was 3.76 mmol·g-1 (422.62 mg g-1), which apparently higher than that of Fe3O4-a and MgMnLDO-a, indicating that the Fe/Mn synergism results in excellent ability for Cd2+ adsorption. Moreover, the composite could efficiently activate peroxymonosulfate (PMS) to rapid degrade PAM with the highest first-order rate constants (kobs = 0.116 min-1) and total organic carbon (TOC) removal rate (67.7 %), which also due to the contribution of Fe/Mn synergism in PMS activation. The cycling of MnIII/MnIV and FeII/FeIII played an important role in activating PMS to generateO2−•, 1O2 and OH for degradation. The composite exhibited both stable adsorption and catalytic performance on wide pH (3–9) and five reuse cycles. Notably, there was mutual promotion between Cd2+ and PAM adsorption, while the coexistence of Cd2+ had slight inhibition on PAM degradation. Overall, the magnetic composite had promising application for purifying heavy metals and pharmaceuticals.