Effective adsorption of non-biodegradable pharmaceuticals from hospital wastewater with different carbon materials

Abstract

Adsorption on carbon materials (AC-F400, AC-PS, AC-RH, CNF and MWNT) has revealed as an effective treatment for the removal of two representative pharmaceutical compounds (carbamazepine, CBZ, and ciprofloxacin, CPX) in ultrapure water, as isolated compounds and as a mixture of both of them. Accordingly, a real pharmaceutical effluent containing these substances was efficiently treated by adsorption with the tested carbon adsorbents. A relatively high adsorption rate (equilibrium time of 4h) and large carbamazepine and ciprofloxacin adsorption capacities (qCBZ=242mgg−1, qCPX=264mgg−1) were found, using adsorbent doses ranging from 2 to 3gL−1, natural pH, temperature of 30°C and stirring rate of 250rpm. Thus, the decreasing in the adsorption removal was observed for both contaminants when the mixture CBZ-CPX was treated, reaching up to 80.5% of decreasing in CBZ adsorption (in presence of CPX) onto F-400 activated carbon. The bi-component adsorption systems were reasonably well-fitted by the extended Freundlich model equation. Meanwhile, the reduction of macroscopic parameters (Total Organic Concentration, TOC, Total Nitrogen, TN, carbonates (CO32−) and aromaticity) in the real hospital wastewater was achieved in high percentages (from 64 to 98.8%). Moreover, the carbon adsorbents were proven as efficient materials in the removal of the pharmaceutical compounds from the hospital effluent matrix; after the treatment, only trace-level concentrations of atenolol and trazodone were detected.