Pore size-matched adsorption of organic pollutants and its pilot application in advanced wastewater treatment

Activated carbon adsorption is a key technology for advanced wastewater treatment, yet the mechanisms governing the removal of macromolecular organics, such as humic substances, remain unclear under long-term full-scale operation. To elucidate the structure-performance relationship governing large molecule adsorption, we proposed a pore size-matching strategy by systematically investigating humic substance adsorption on activated carbons with varying pore structures. Results show that mesopore volume and average pore diameter, rather than specific surface area or iodine number, are the primary factors controlling adsorption capacity. Among eight commercial carbons, a coal-derived activated coke (AC-Coke-I) exhibited superior performance, with a maximum humic acid uptake of 16.83 mg g^-1. A pilot-scale adsorption system (3000 m³ d^-1) confirmed its effectiveness, achieving 40 % COD_Mn removal initially and maintaining 13 % removal after 15 months, with a cumulative adsorption capacity of 30.4 mg-COD_Mn g^-1. AC-Coke-I also effectively removed emerging contaminants, including antibiotics and perfluorinated compounds. After three thermal regenerations, adsorption capacity recovered to ∼65 % of fresh material. Techno-economic analysis indicates an average operating cost of 0.019 USD m^-3, substantially lower than conventional processes such as ozonation. Collectively, this work demonstrates a pore size-matching strategy and establish a mechanistic framework for designing efficient and cost-effective adsorbents for municipal wastewater advanced treatment.