Flocculation inspired combination of layered double hydroxides and fulvic acid to form a novel composite adsorbent for the simultaneous adsorption of anionic dye and heavy metals

•A multifunctional composite adsorbent was prepared through flocculation process.•Mg2Al layered double hydroxide and fulvic acid were combined by physical interaction.•The composite adsorbent can effectively capture anionic orange II by anion exchange.•The composite adsorbent presents good adsorption performance for heavy metal cations.•The composite adsorbent can simultaneously uptake anionic orange II and heavy metal cation.