| Sulfonamides, the synthetic broad-spectrum antibiotics, are among the most widely used veterinary antibiotics in human, livestock farming and aquaculture, which can lead the sulfonamides residue in water exceeding bid badly. However, the persistent abuse makes the water in the excessive residual sulfonamides residues, which are ultimately treat to ecosystem balance. Biological methods is not good to remove of sulfonamides due to it is biological poison rational characteristics. The adsorption method which is included in physical-chemistry methods has become the most commonly method to remove sulfonamides residue in water environment because of the low energy consumption, no by-product and the reused absorbents. In order to solve the drawbacks of traditional adsorbent such as the complex material synthesis, high cost, complex production process, smaller specific surface area and the lower adsorption rate, we chose a single, cheaper biomass materials as the carbon source, the production process only through two simple steps including carbonization and activation, prepared the adsorbent material with high specific surface area and strong adsorption rate.In this paper, sulfamethazine(SMZ) was used as research object. Firstly, looking for biomass resources with cheap, substantial, renewable and rich carbon content as carbon source, and in this paper we finally chose shrimp shell, bovine bone and yeast as carbon source. Then the raw materials were carbon under the protection of N2 at higher temperature. Finally, activating by KOH and selecting the optimal activation conditions. The morphology and structure were analyzed via different characterization methods like scanning electron microscope(SME), transmission electron microscopy(TEM) and so on. And the adsorption processes for hierarchically porous carbons from sustainable biomass materials were searched via adsorption isotherms, adsorption kinetics and regeneration performance experiments. The detailed work was as follows.(1) Shrimp shell was successful converted into noval N-doped hierarchically porous carbons(N-HPCs) via a simple self-template carbonization and KOH activation. The morphology, structure and parameters as specific surface area and porosity were analyzed. The results show that: the specific surface area, porosity and yield of the products relevanted with the KOH mass ratio and activation temperature. Studying the influence of parameters found that when KOH: carbonization of shrimp shell mass ratio was 2:1 and activation temperature reached 850 oC was the optimum preparation condition, the prepared adsorbent exhibited the highest specific surface area and the maximum total pore volume for 3171 m2 g-1 and 1.934 cm3 g-1 respectively. The adsorption isotherm data were fitted Langmuir isotherm model very well, and the adsorption increased with the increasing temperature. The pseudo-second-order rate model described adsorption kinetics data well. And the optimum adsorbent exhibited excellent property of regeneration and stability which provided a feasible solution for the removal of the residues of antibiotics in the water environment.(2) KOH-activated hierarchical porous carbon prepared from bovine bone with some superior characterizes, such as larger specific surface area and porosity, good chemical stability and different sizes of the channels, were used as adsorbents. The physico-chemical properties of hierarchical porous carbons were characterized by FT-IR, SEM, TEM, Raman and element analysis in detail. Results showed that the pore development was significant at temperature >700 oC, and reached a maximum BET surface area(3231.8 m2 g-1) and total pore volume(1.976 cm3 g-1) when the temperature reached 850 oC and the mixing ratio of 1:3(bovine bone char: KOH)(wt: wt). It was also observed that significant changes occurred on the material surface after the activation procedure through the SEM, TEM and FT-IR analysis. The experimental equilibrium data were analyzed using the isotherms of Langmuir and Freundlich. The adsorption kinetics of pseudo-first-order and pseudo-second-order were used for the kinetics study. The adsorption results showed that: adsorption isotherms of SMZ obtained from batch experiments were better fitted by Langmuir compared with Freundlich model. Adsorption kinetics obeyed the pseudo-second-order model can fit the adsorption process well. From the adsorption thermodynamic parameters(ΔG°, ΔS° and ΔH°) indicating the adsorption was a spontaneous and endothermic process. BHPC-850-3 also exhibited excellent property of regeneration and stability which provided a feasible solution for the removal of the residues of antibiotics in the water environment(3)Yeast, as an abundant, environmental-friendly and renewable biomass source, contains a large number of carbon and nitrogen elements, is regarded as the preferred raw material to prepare of the adsorption of carbon materials. It was successfully converted into hierarchically porous carbon(YHPC-3) via a simple self-template carbonization and KOH activation. The physical-chemical properties of YHPC-3 were characterized by FT-IR, SEM, TEM, Raman, BET and elemental analysis. The results showed that YHPC-3 exhibited the highest specific surface area and total pore volume were 3808 m2 g-1 and 2.202 cm3 g-1, respectively, and was used to effectively eliminate SMZ from water. Batch adsorption results showed increasing temperature was in favor of adsorption and YHPC-3 had high adsorption affinity toward SMZ over a broad pH range. Adsorption isotherm data were fitted well with Langmuir model very well. The pseudo-second-order rate model described adsorption kinetics data well and adsorption process were governed predominately by intra-particle diffusion and film diffusion. The thermodynamic parameters indicated the adsorption was a spontaneous and endothermic process. YHPC-3 also exhibited excellent property of regeneration and stability. YHPC-3 showed excellent adsorption performance and good chemical stability, provides an important reference value for the effective removal of antibiotic residues in the environment. |
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