Sorption affinities of sulfamethoxazole and carbamazepine to two sorbents under co-sorption systems

• Published in: Environmental pollution (1987) Vol. 194; pp. 203 - 209
• Main Authors: Wang, Chi, Li, Hao, Liao, Shaohua, Zhang, Di, Wu, Min, Pan, Bo, Xing, Baoshan
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.11.2014; Elsevier
• Subjects: Absorption, Physicochemical; Adsorbents; Adsorption; Affinity; Applied sciences; Biological and physicochemical phenomena; Biological and physicochemical properties of pollutants. Interaction in the soil; Carbamazepine - analysis; Carbamazepine - chemistry; Carbon - chemistry; Charcoal - chemistry; Competition; Competitive sorption; Complementary sorption; Desorption hysteresis; Earth sciences; Earth, ocean, space; Engineering and environment geology. Geothermics; Exact sciences and technology; Hysteresis; Nanotubes, Carbon - chemistry; Natural water pollution; Pollutants; Pollution; Pollution abatement; Pollution, environment geology; Soil and sediments pollution; Sorption; Sorption strength; Sulfamethoxazole - analysis; Sulfamethoxazole - chemistry; Thermodynamics; Water treatment and pollution; Complementary sorption; Thermodynamics; Desorption hysteresis; Competitive sorption; Sorption strength; Emerging contaminant; Coadsorption; Adsorption capacity; Carbon nanotubes; Pollution; Sulfamethoxazole; Activated carbon; Hysteresis; Organic compounds; Drug; Pollutant behavior; Competitive reaction; Desorption; Inorganic adsorbent; Carbamazepine; Singlewalled nanotube; Environment; Thermodynamic analysis; Nanostructured materials; Comparative study
• ISSN: 0269-7491; 1873-6424
• DOI: 10.1016/j.envpol.2014.07.033

The Kd of sulfamethoxazole (SMX) on activated carbon (AC) was larger than that of SMX on single-walled carbon nanotubes (SC), but the competition of SMX with carbamazepine (CBZ) for adsorption sites was weaker on AC than SC. Thus, a large Kd value does not necessarily reflect a high affinity. The analysis of the apparent sorption, competition, desorption hysteresis, and the sorption thermodynamics for SMX and CBZ did not provide sufficient information to distinguish their sorption affinities. The release of the adsorbed CBZ was not altered with SMX as the competitor, but SMX release increased significantly after CBZ addition. The higher sorption affinity of CBZ may be explained by the interactions of the CBZ benzene rings with the aromatic structures of the adsorbents. Although the thermodynamic meaning cannot be described, the release ratio of the adsorbed pollutants provides useful information for understanding pollutant sorption strength and associated risks. •Both sulfamethoxazole (SMX) and carbamazepine (CBZ) show high sorption.•SMX and CBZ complementarily occupy sorption sites with different properties.•SMX could not replace the adsorbed CBZ on single-walled carbon nanotubes.•The release ratios of SMX increase after CBZ addition, but not vice verse.•CBZ adsorbs with much higher sorption affinity than SMX. The release ratio of the adsorbed pollutants provides useful information for understanding pollutant sorption strength and associated risks.