Sustainable valorization of electrocoagulation sludge in ceramic kaolinite membrane fabrication and its application to seawater pretreatment for SWRO desalination

This study explores the sustainable valorization of dye electrocoagulation sludge (EC-Sludge) as a novel additive to enhance kaolinite-based flat ceramic membranes for seawater pretreatment prior to reverse osmosis desalination . Driven by the demand for low-cost, efficient, and eco-friendly membranes, incorporating up to 30 wt% EC-Sludge (containing aluminum hydroxide), significantly improved kaolinite membrane properties. The optimal membrane (including 15 wt% EC-Sludge) exhibited an average pore size of 1.43 μm, porosity of 39.30 %, permeability of 2580 L m −2 h −1 bar −1 , and mechanical strength of 21 MPa, demonstrating its suitability for microfiltration (MF) applications. MF tests of raw seawater confirmed the excellent pretreatment performance of the kaolinite/sludge membrane, achieving 95.24 % turbidity rejection, 81.14 % TOC removal, and 71.20 % COD reduction, while effectively lowering the SDI from 5.63 to 3.47. Fouling analysis revealed predominantly reversible cake layer formation, with up to 80 % flux recovery post-cleaning. The findings highlight the replicability and ecological potential of this approach for advancing sustainable desalination technologies . • Valorizing electrocoagulation (EC) sludge in kaolinite-based membrane fabrication. • EC-Sludge improves kaolinite membrane properties for microfiltration application. • The prepared membrane has desirable properties and is well placed in MF range. • MF kaolinite/sludge membrane enhanced raw seawater quality for SWRO desalination. • Simple water washing of the membrane leads to regenerate 80 % of its original flux.