| The rapid development of printing and dyeing industries has proposed the highly efficient treatment of organic dyes in untreated water to be a critical issue in the areas of water treatment.Adsorption was considered to be one of the most useful methods in treating dyes due to excellent attribution i.e.simplicity in operation,high efficiency with no pollution,and the critical point was to design adsorbent with high removal capacity and stability.Porous carbons were received the most attention as adsorbents to removal dye due to simplicity in operation and low-cost.Metal-organic frameworks(MOFs)were suitable precursors for the production of carbons.This thesis reported the preparation of carbons from MOFs containing imidazole ligands named as ZIFs,and the as-made carbons showed varied microstructure and surface-doping chemistry according to the preparation conditions.All these carbons were explored as adsorbents for dyes removal from water using Rhodamine B(Rh B)as a model dye,and the main contents for the thesis were introduced as follows:Firstly,ZIF-8 particles were synthesized in multiple batches by a self-diffusion method at room temperature using methanol as media solution,zinc nitrate as metal source and dimethylimidazole as the organic ligands.On the other hand,hydrothermal treatment of glucose with varied concentration(5,10,and 20%)was performed at the low-temperature condition of 160°C to obtain partially polymerized glucose solution not solid hydrochar,and then the collected solution were coated with ZIF-8 particles to form ZIF-8@glucose composites.The carbonization of composites were performed at different temperatures(800-1000°C)under inert atmosphere to obtain carbons with varied porous structure and nitrogen-doping,indicating that the carbons obtained from carbonization at 1000°C exhibited the best adsorption performance.Significantly,the as-made carbons(GZC-10)from carbonization of ZIF-8 at 1000°C with the coating glucose concentration of 10%showed the largest Rh B removal amount of highly up to 383 mg/g at room temperature,where the efficiency for adsorbed amount was still highly up to 55%even after continuous five cycling performance.The kinetic results indicated that the equilibrium adsorbed amount of GZC-10 was up to 283 mg/g,while the sample(GZC-0)from ZIF-8 with the largest surface areas of 1100 m~2/g only had the eqilibrium adsorbed Rh B amount of only 115 mg/g under the same condition.The conclusions indicated that surface areas was not a decisive factor in the dyes removal,and GZC-10 with mesoporosity of 30.9%and rich pyrrolic and graphitized N-species made it have superior removal performance.Secondly,bimetallic Zn/Co-ZIFs particles were synthesized at room temperature using different ratio of Zn/Co in the compositions,where methanol was used as media solution,zinc(cobalt)nitrates were used as metal source,and dimethylimidazole was used as organic ligand.Based on the attributions of low boiling point for metallic Zn,several types of carbons were obtained from the direct carbonization of the bimetallic ZIFs with varied porous structure and Co-doping properties,and the as-made carbons were used as adsorbents for the application of Rh B removal performance.The results indicated that the presence of metallic Co-species in composition made these carbons with largely reduction in surface areas,where the carbons(GZC-0)from pure ZIF-8showed surface areas of 1100 m~2/g,while the carbons(ZCC-7)from bimetallic MOFs with ratio of Co/Zn to be 3/7 showed surface areas of 340 m~2/g.The adsorption results indicated that carbonization of biometallic ZIFs showed excellent removal capacity as compared to that of carbons from pure(Co)ZIF-67 and pure(Zn)ZIF-8,in which the as-made carbons(ZCC-7)with a ratio of Zn/Co to be 7/3 showed equilibrium removal capacity for Rh B up to be 224,210 and 237 mg/g at 0,25,and 40°C,respectively.All these results also confirmed the presence of partial chemisorption in the system during the removal procedure. |
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