Adsorption of Diclofenac from Aqueous Solution onto Carbon Xerogels: Effect of Synthesis Conditions and Presence of Bacteria Article uri icon

abstract

  • Different carbon xerogels (CXs) were synthesized by the polymerization of resorcinol (R) and formaldehyde (F) catalyzed by cesium carbonate (Cs), and by varying the molar ratio R/Cs. The CXs were labeled as XCs-100, XCs-500, XCs-1000, and XCS-2000, corresponding to the R/Cs ratio of 100, 500, 1000, and 2000, respectively. The surface chemistry of the CXs varied very slightly with the R/Cs ratio because the point of zero charge (pHPZC) and the concentrations of basic and acid sites were almost independent on the R/Cs ratio. The surface areas of the four CXs decreased slightly by increasing the R/Cs ratio; however, XCs-500 presented the highest volume of pores and mesopores and mesopore surface area. At a concentration of diclofenac (DCF) at equilibrium of 800 mg/L, the adsorption capacities of XCs-100, XCs-500, XCs-1000, and XCs-2000 towards DCF in aqueous solution were 132.0, 184.6, 126.5, and 126.4 mg/g, respectively. Hence, the adsorption capacity of XCs-500 was about 1.4 times larger than those of the other CXs. The adsorption capacity of XCs-500 was reduced by increasing the solution pH due to electrostatic interactions, whereas the adsorption capacity was increased by raising the temperature, confirming that the adsorption was endothermic. The bacteria Escherichia coli adhered to the surface of XCs-500 forming a biofilm, and the presence of bacteria enhanced 1.3 times the adsorption capacity of XCs-500 towards DCF from water solutions. © 2020, Springer Nature Switzerland AG.

publication date

  • 2020-01-01