Low-cost electrochemical filtration carbon membrane prepared from coal via self-bonding

Electrochemical filtration membranes are highly effective for wastewater treatment. However, their relatively high production cost may limit their large-scale production and industrial application. In this work, a low-cost and efficient electrochemical filtration carbon membrane (ECM) was developed via a simple method using coal as the precursor and relying on its self-bonding property. The effects of raw coal blending ratio, carbonization temperature and the addition of pore former on the performance of ECMs were systematically studied. The electrochemical filtration efficiency of the ECM was evaluated using four typical organic pollutants (phenol, bisphenol A (BPA), tetracycline (TC) and rhodamine B (RhB)). Finally, the oxidation mechanism of the ECM was also explored. The high caking property of the raw coal resulted in high mechanical strength ECMs but also led to low porosity and small pore size, which may cause high hydraulic resistance. The overall performance of the ECMs was improved by using blended coal samples as raw materials. The ECM obtained by the optimal preparation conditions exhibited a porosity value of 51.83%, mean pore width of 0.88 μm, mechanical strength of 78.8 N, electrical resistivity of 33.91 mΩ cm and high permeability (393.17 L·m−2·h−1·bar−1). Under a cell potential of 2.0 V, the removal rates of the ECM for all four pollutants were greatly enhanced by electrochemical oxidation, and the electrochemical oxidation activity of the ECM involve both direct and indirect oxidation. Overall, these results demonstrated the potential applicability of ECMs for large-scale production and organic wastewater treatment.