Cd(II) and fenaminosulf adsorption by zeolite modified with plant extract and chemical modifier

To explore the adsorption effect of composite-modified zeolite (Ze) on heavy metal and bactericide, Ze was single-modified with the extract (E) from Eupatorium adenophorum Spreng. Dodecyl dimethyl betaine (BS), ethylene diamine tetraacetic acid (ED), and sodium alginate (SA) were compositely modified on E-modified Ze (E-Ze) to form BS-modified E-Ze (BS/E-Ze), ED-modified E-Ze (ED/E-Ze), and SA-modified E-Ze (SA/E-Ze), respectively. The adsorption isothermal and kinetics of Cd(II) and fenaminosulf by different composite-modified Zes were studied, and the effects of pH, temperature, and ionic strength on the adsorption process were compared. The outcomes indicated that composite-modified Zes' adsorption process of Cd(II) and fenaminosulf was suitable for describing by Langmuir and Freundlich models, respectively. The adsorption capacity of Cd(II) and fenaminosulf by different composite-modified Zes all ranged in the order of BS/E-Ze > ED/E-Ze > SA/E-Ze > E-Ze > Ze. With the increasing modification ratio of the composite modifier, the adsorption effect of Cd(II) first increased and then decreased, whereas the adsorption effect of fenaminosulf increased. The adsorption amount on different composite-modified Zes decreased for Cd(II) and increased first and then reduced for fenaminosulf with the increase in ionic strength. Increasing pH and temperature were beneficial to Cd(II) adsorption but not conducive to fenaminosulf adsorption. The adsorption process was spontaneous, endothermic for Cd(II), exothermic for fenaminosulf, and entropy-increasing reaction, and the Cd(II) and fenaminosulf adsorption rate was controlled by chemical and physical reaction, respectively.