Insights into the Synergistic, Neutral, and antagonistic adsorption effects in Cobalt-Containing wastewater treatment

[Display omitted] •Synergistic, neutral, and antagonistic effects in simultaneous adsorption were illustrated.•Co(II) causes a transition in the adsorption form of TC on TNP.•n-hexane hinders the ion transport route for TNP adsorption of Co(II).•The adsorption of Co(II) and NH4+ completely differentiate in antagonistic adsorption. In the adsorption treatment of multi-component wastewater, complex simultaneous adsorption effects occur due to the various interactions among the adsorbent and adsorbates. However, these effects haven’t been comprehensively analyzed. In this study, using cobalt-containing multi-component wastewater as a model, the simultaneous adsorption behavior was deconvoluted and analyzed in terms of synergistic, neutral, and antagonistic effects. For the synergistic effect, the coexisting Co(II) enhanced the adsorption of tetracycline by modulating adsorption state according to the number of adsorbates captured per site. For the neutral effect, the trade-off between narrowed transport routes and accelerated internal diffusion causes almost no change in the adsorption capacity and energy of Co(II). Finally, for the antagonistic effect, the coexisting NH4+ have intrinsic competition with Co(II), and the adsorption-preferable Co(II) occupy the new adsorption sites created by the increased concentration of NH4+. This study contributes to the understanding of the interactions in adsorption engineering for coexisting adsorbates.