Catalytic conditioning and mechanism of sludge with a green conditioner MgO(110): The first example of boosting sludge conditioning by facet engineering

With an intention to find new green-effective catalytic conditioners of sludge treatment, MgO nano-powders with preferential exposure facet (110) or (100) were prepared as sludge conditioners of sludge for the first time. The synthesized MgO nano-powders significantly enhanced the dewaterability and filterability of sludge which were highly sensitive to facet exposure. The Disintegration degree (DD) of sludge treated with MgO(110) reached 41.6 %, while that with MgO(100) and commercial MgO was only 35.7 % and 27.7 %, respectively. Boosting catalytic conditioning effect of (110) facet exposure was mainly ascribed to strong adsorption of O 2 in the Pauling-type mode by low coordination sites. Theoretical calculation indicated that its adsorption energy of O 2 reached was 4.5 folds that of MgO(100). The adsorption mode and high energy facilitated the generation of 1 O 2 as a key initial reactive oxygen species (ROS), leading to the effective conversion of bound water into free water. These findings provided a methodological reference for developing alternative catalytic conditioners through facet engineering to promote sludge dewatering and reduction.