A two-stage adsorption strategy based on micro–mesopore synergy for cost-effective treatment of acrylonitrile wastewater

Acrylonitrile (AN) wastewater, characterized by high toxicity, poor biodegradability, and elevated treatment costs, poses a major challenge to the sustainable development of the chemical industry. To support concentration-dependent adsorbent screening for coal-based granular activated carbons (CGACs), this study established a modular adsorption and techno-economic evaluation framework was established. Two independent time-constrained modules, namely high-concentration loading (COD approximately 500 mg/L) and low-concentration polishing (COD approximately 50 mg/L). ere used to compare the adsorption behavior of micropore and mesopor CGACs. Micropore- CGACs showed higher adsorption capacity in the high-concentration conditions, with CGAC-8 reaching an equilibrium capacity of 89.43 mg/g, whereas mesopore- CGACs exhibited more favorable pore accessibility and mass-transfer behavior during low-concentration polishing. The techno-economic assessment further incorporated working capacity, regeneration loss, energy consumption, and material cost was established for comparative assessment under standardized conditions. Under the defined assumptions, the CGAC-8 front + CGAC-2 polishing configuration was identified as an economically preferred conceptual option. These results provide a comparative basis for staged CGAC selection and highlight the need for continuous-flow breakthrough tests，multi-cycle regeneration experiments, and validation with real wastewater matrices before practical application.