Highly efficient and economic treatment of wastewater sludges and wastewaters in one way is a challenging issue in the water treatment field. Herein we present a waste-to-resource strategy for rational fabrication of low–cost ceramic membranes, which simultaneously addresses the treatment of heavy metal-laden sludges and the separation of oil-in-water (O/W) emulsions. A thermal conversion mechanism is proposed for complicated reactions between simulated nickel-laden wastewater sludge and bauxite mineral. In addition to full stabilization and recycling of heavy metal wastewater sludges, rational tailoring of ceramic membrane structures can also be realized to achieve high water flux and favorable mechanical and surface properties. With rational structure design, the tailored spinel-based ceramic membranes exhibited high rejection and high flux (7473 LMH·bar⁻¹) simultaneously for separation of oily wastewater, outperforming other reported state-of-the-art ceramic membranes. The membrane fouling mechanism revealed the dominance of cake layer formation at low cross flow velocities, while a combined model of cake layer formation and pore blocking dominated membrane fouling at high cross-flow velocities. The proposed strategy can be potentially extended toward design of functional ceramic membranes derived from other heavy metal wastewater sludges and for other water treatment applications.

Membrane-based separation processes can improve separation efficiency and reduce the environmental hazards and energy costs of traditional separation processes. Mixed matrix membranes (MMMs) with broad development prospects are frequently restricted by interfacial incompatibility and the blockage of gas transport channels in the filler matrix. Here, we report a new type of high-valence metal-induced microporous polymer (HMMP-1) filler, with a high density of free amine groups, and having excellent alkaline stability. The HMMP-1 nanoparticles were incorporated into polyvinylamine (PVAm) to prepare facilitated transport mixed matrix membranes (MMMs). The resulting HMMP-1 based MMMs maintain their pore aperture structure, which is mainly due to the excellent compatibility between the polymer component in the HMMP-1 and PVAm. Amine-rich nanochannels with appropriate pore size allow rapid CO₂ transport through the filler pores by preferential adsorption monomolecular surface diffusion, leading to high CO₂ permeance and excellent separation performance for CO₂/CH₄, CO₂/N₂ and CO₂/H₂ compared with many other reported membranes. A techno-economic evaluation suggests that the MMM is feasible for carbon capture from post-combustion flue gas.