Lower-temperature preparation of porous Al2O3 supports for O/W separation membranes by recycling mixed-dimensional attapulgite clay as sintering aid

Ceramic membranes have drawn attention in oil-in-water (O/W) treatment due to natural hydrophilicity and excellent chemical stability, however their application was restricted by high cost. In this work, a cost-effective Al 2 O 3 -based ceramic support was prepared at sintering temperature of 1500 °C with low-cost mixed-dimensional attapulgite (MDATP) as aid. The composite support with addition of 10 wt% MDATP and 3 wt% powdered carbon possessed an average pore size of 3 µm, bending strength of 63.7 MPa, pure water permeability of 1.32 × 10 4 L·m −2 ·h −1 ·bar −1 . Mullite was formed due to the reaction between Al 2 O 3 and SiO 2 in MDATP during sintering, which played a key role in preparing support with corrosive resistance performance. Then, a superwetting microfiltration (MF) membrane with pore size of 0.18 µm and permeability of 1470 L·m −2 ·h −1 ·bar −1 was obtained by coating ATP nanofiber on the Al 2 O 3 -MDATP support with sintering temperature of 600 °C. The molecular dynamics results showed that the ATP can repel oil fouling with interaction energy of − 872 Kcal·mol −1 . The excellent O/W emulsion separation efficiency of the MF membrane further demonstrated the feasibility of ATP and its by-products in decreasing membrane cost and improving performance.