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Removal of sulfamethazine antibiotics using cow manure-based carbon adsorbents
Tzeng, T.-W.; Liu, Y.-T.; Deng, Y; Hsieh, Y.-C.; Tan, C.-C.; Wang, S.-L.; Huang, S.-T. & Tzou, Y.-M.
Abstract
Low-cost adsorbents, e.g., cow manure-based
carbon, provide alternatives to remove veterinary antibiotic
sulfamethazine (SMT) from contaminated water bodies. In
this study, the chemical structures and compositions of cow
manure (CM) carbonized at 400, 600, and 800 °C (CM400,
CM600, and CM800) were examined using elemental
analyzer (EA), Brunauer–Emmett–Teller, and spectroscopic
techniques. Adsorptions of SMT on CM samples
were conducted as functions of pH, hydrophobicity, and
ionic strengths. Results of EA and spectroscopic analyses
suggested that the raw CM and CM400 samples contained
the highest amounts of O-containing groups and aliphatic
domains. Amounts of such two chemical groups decreased
as carbonization temperatures increased. The specific surface
areas and total pore volumes of CM samples increased
significantly when the carbonization temperatures exceeded
600 °C. SMT adsorption on CM samples could be described
essentially by the pseudo-second-order kinetic, intra-particle
diffusion, and Freundlich isotherm models. Low pH and
ionic strength were favorable for SMT adsorption in CM
samples, particularly for the CM800, because a strong π+ – π
electron donor–acceptor interaction (π+ – π EDA) was
formed between SMT and CM surfaces enriched with
hydrophobic domains. Further, the high adsorption affinity
of SMT to the CM600 and CM800 samples was attributed
in part to their larger surface areas and total pore volumes.
Generally, CM-based materials carbonized [600 °C
showed relatively stable structures and exhibited strong
aromatic properties. Moreover, maximum adsorption
capacities of SMT on the CM800 sample (37–39 mM/kg)
were significantly higher than those of other common
adsorbents (0.02–35.93 mM/kg).
Keywords
Sulfonamide; Animal wastes; Carbonization; Adsorption; π+ – π EDA
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