A novel carbon nanotube–magnesium oxide composite with excellent recyclability to efficiently activate peroxymonosulfate for Rhodamine B degradation

There is an urgent need for an eco-friendly and efficient route to treat the organic pollutants in wastewater. Therefore, we report a facile synthesis of carbon nanotube–magnesium oxide composite (CNTs/MgO) which can efficiently activate peroxymonosulfate (PMS) to degrade Rhodamine B (RhB). Fabricated CNTs/MgO was characterized by XRD, FTIR, SEM, TEM, BET, XPS, and Raman. The results showed that the carbon nanotubes uniformly entangled on the MgO whiskers and linked to the MgO by Mg–C and C–O bonds. The effects of temperature, pH value, CNTs/MgO dosage, PMS dosage and the ratio of MgO/CNTs on degradation of RhB were conducted to determine the activation performance of CNTs/MgO. The catalytic degradation process was carried out in a wide pH range of 3–9, and 100% of RhB was degraded in 20 min under optimized conditions. Moreover, the efficient degradation performance was attributed to singlet oxygen generated in the PMS&CNTs/MgO system. The excellent activation properties of CNTs/MgO was derived from the enhanced electron transport performance and chemical bonding between MgO and CNTs. In addition, this work provides an innovative design for the development of novel PMS catalysts without transition metal components.