Insights into mass transfer mechanism and micro-interaction of melanoidin adsorption on polyethyleneimine-functionalised pomelo-peel-derived aerogel

•Pomelo peel was creatively converted into environmental remediation adsorbent.•Novel PEI-PPA efficiently eliminates melanoidins from spent wash.•Interpretation of adsorption mechanism was via phenomenological models.•The micro-interaction was deciphered by molecular simulation.