Anoxic conditions are beneficial for abiotic diclofenac removal from water with manganese oxide (MnO(2))

This is the first study examining pharmaceutical removal under anoxic conditions with MnO(2). This study compares the abiotic removal of seven pharmaceuticals with reactive MnO(2) particles in the presence of oxygen (oxic conditions) and in the absence of oxygen (anoxic conditions). Due to the novelty of pharmaceutical removal under anoxic conditions, the influence of phosphate buffer, pH, and MnO(2) morphologies is also examined. Results show that over 90% of diclofenac is removed under anoxic conditions. Additionally, we found that (1) anoxic conditions are beneficial for diclofenac removal with MnO(2), (2) phosphate buffer affects the pharmaceutical removal efficiencies, (3) higher pharmaceutical removal is obtained at acidic pH compared to that at neutral or alkaline conditions, and (4) amorphous MnO(2) removes pharmaceuticals better than crystalline MnO(2). The pharmaceutical molecular structure and properties, MnO(2) properties especially reactive sites of the MnO(2) surface, are important for degradation kinetics. This study provides a fundamental basis towards understanding pharmaceutical degradation with MnO(2) under anoxic conditions, and development of a cost-effective, sustainable technology for removal of pharmaceuticals from water. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s11356-018-1569-2) contains supplementary material, which is available to authorized users.