In this work we investigated the effect of nitric acid concentration on the pore structure,surface chemistry and liquid phase adsorption of olive stone based activated carbon prepared by mixing process using phosphori...In this work we investigated the effect of nitric acid concentration on the pore structure,surface chemistry and liquid phase adsorption of olive stone based activated carbon prepared by mixing process using phosphoric acid and steam as activating agents.Chemicals and textural characterization show that the increase of HNO3concentration increases considerably the total acidic groups but decreases specific surface area and pore volume.The study of adsorption in aqueous solutions of two organics,phenol and methylene blue,on raw and oxidized activated carbon indicates that the treatment of mixed activated carbon with different concentrations of nitric acid improves the adsorbent capacity for methylene blue at HNO3concentrations less or equal to 2 mol·L 1,while it has a negative effect on phenol adsorption.展开更多
In order to decisively determine the adsorption selectivity of zirconium MOF(UiO-66) towards anionic versus cationic species, the adsorptive removal of the anionic dyes(Alizarin Red S.(ARS), Eosin(E), Fuchsin Acid(FA)...In order to decisively determine the adsorption selectivity of zirconium MOF(UiO-66) towards anionic versus cationic species, the adsorptive removal of the anionic dyes(Alizarin Red S.(ARS), Eosin(E), Fuchsin Acid(FA)and Methyl Orange(MO)) and the cationic dyes(Neutral Red(NR), Fuchsin Basic(FB), Methylene Blue(MB),and Safranine T(ST)) has been evaluated. The results clearly reveal a significant selectivity towards anionic dyes. Such an observation agrees with a plethora of reports of UiO-66 superior affinity towards other anionic species(Floride, PO_4^(3-), Diclofenac sodium, Methylchlorophenoxy-propionic acid, Phenols, CrO_4^(2-), SeO_3^(2-), and AsO_4^-). The adsorption process of ARS as an example has been optimized using the central composite design(CCD). The resultant statistical model indicates a crucial effect of both pH and sorbent mass. The optimum conditions were determined to be initial dye concentration 11.82 mg.L^(-1), adsorbent amount 0.0248 g, shaking time of 36 min and pH 2. The adsorption process proceeds via pseudo-second order kinetics(R^2= 0.999). The equilibrium data were fit to Langmuir and Tempkin models(R^2= 0.999 and 0.997 respectively). The results reveal an exceptional removal for the anionic dye(Alizarin Red S.) with a record adsorption capacity of400 mg·g^(-1). The significantly high adsorption capacity of UiO-66 towards ARS adds further evidence to the recently reported exceptional performance of MOFs in pollutants removal from water.展开更多
Inverse emulsion polymerization was employed to synthesize inverse emulsion Cd（Ⅱ） imprinted polymers （IEⅡ P）. The morphology and functional groups of IEⅡP were characterized by SEM,FTIR and TG. Static adsorptio...Inverse emulsion polymerization was employed to synthesize inverse emulsion Cd（Ⅱ） imprinted polymers （IEⅡ P）. The morphology and functional groups of IEⅡP were characterized by SEM,FTIR and TG. Static adsorption experiments and competitive adsorption test were used to evaluate the adsorption ability of IEⅡP. The adsorption capacity of polymers could reach 86.7 mg·g^-1 under the optimal adsorption conditions. The pseudo second order kinetic model and Langmuir isotherm model could be used to analyze the experimental data well. The adsorption process of IEⅡP was chemical adsorption process and monomolecular type. Thermodynamic parameters showed that the adsorption process was endothermic and could occur spontaneously. The selectivity coefficients k of Cd^2＋/v, Cd^2＋/Zn^2＋ and Cd^2＋/Cu^2＋ were 2.4998, 1.2437 and 4.6882, respectively. The proposed method provides a new thought for removing Cd（Ⅱ） in water samples.展开更多
Wastewater containing high concentrations of ammonia can be harmful to aquatic life and degrade the water quality. Wastewater containing ammonia is usually removed by conventional methods such as aeration in towers, b...Wastewater containing high concentrations of ammonia can be harmful to aquatic life and degrade the water quality. Wastewater containing ammonia is usually removed by conventional methods such as aeration in towers, biological treatment and adsorption of the ammonium ion to the zeolite surface. However, these methods are less effective and relatively expensive. Therefore there is a need for alternative technologies that can improve the efficiency of ammonia removal from wastewater. This study aims to obtain the process of ammonia removal through a combination of absorption in the membrane contactor and the advance oxidation process in the hybrid plasma-ozone reactor. Wastewater containing ammonia used in the study was a synthetic wastewater with a concentration of about 800 ppm. In the experiment, the wastewater fi＇om the reservoir was firstly passed into the membrane contactor on the shell side, and then mixed with ozone from the ozonator befbre entering the plasma reactor, and finally was circulated back to the reservoir. Meanwhile, the absorbent solution was sent to the lumen fiber in membrane contactor. Experimental results showed that the ammonia removal efficiency increases with increasing in circulation rate and temperature of the wastewater. The highest efficiency of ammonia removal obtained from the experimental results was 77%.展开更多
The present study demonstrates the potential of the simulation based on-line synthesis, design and optimization strategy for pressure swing adsorption （PSA） processes developed in our earlier study by implementing o...The present study demonstrates the potential of the simulation based on-line synthesis, design and optimization strategy for pressure swing adsorption （PSA） processes developed in our earlier study by implementing on an actual two-bed unit. The unit is very flexible and allows process synthesis from the PSA cycle configuration point of view. The model parameters are regressed and updated using live experimental data. The on-line monitoring and controlling of the operating parameters and operating configurations are done by multi-loop processor programmable logic controller. Separation of air into nitrogen free oxygen as raffinate stream and enriched nitrogen as extract stream using 5A zeolite as adsorbent has been chosen as a specific system for implementing the strategy. The philosophy of the typical optimization and process synthesis exercise implemented on the unit is described. The results show the successful implementation of the developed strategy on the two-bed O2-PSA unit and the application of this general approach to commercial PSA processes.展开更多
文摘In this work we investigated the effect of nitric acid concentration on the pore structure,surface chemistry and liquid phase adsorption of olive stone based activated carbon prepared by mixing process using phosphoric acid and steam as activating agents.Chemicals and textural characterization show that the increase of HNO3concentration increases considerably the total acidic groups but decreases specific surface area and pore volume.The study of adsorption in aqueous solutions of two organics,phenol and methylene blue,on raw and oxidized activated carbon indicates that the treatment of mixed activated carbon with different concentrations of nitric acid improves the adsorbent capacity for methylene blue at HNO3concentrations less or equal to 2 mol·L 1,while it has a negative effect on phenol adsorption.
文摘In order to decisively determine the adsorption selectivity of zirconium MOF(UiO-66) towards anionic versus cationic species, the adsorptive removal of the anionic dyes(Alizarin Red S.(ARS), Eosin(E), Fuchsin Acid(FA)and Methyl Orange(MO)) and the cationic dyes(Neutral Red(NR), Fuchsin Basic(FB), Methylene Blue(MB),and Safranine T(ST)) has been evaluated. The results clearly reveal a significant selectivity towards anionic dyes. Such an observation agrees with a plethora of reports of UiO-66 superior affinity towards other anionic species(Floride, PO_4^(3-), Diclofenac sodium, Methylchlorophenoxy-propionic acid, Phenols, CrO_4^(2-), SeO_3^(2-), and AsO_4^-). The adsorption process of ARS as an example has been optimized using the central composite design(CCD). The resultant statistical model indicates a crucial effect of both pH and sorbent mass. The optimum conditions were determined to be initial dye concentration 11.82 mg.L^(-1), adsorbent amount 0.0248 g, shaking time of 36 min and pH 2. The adsorption process proceeds via pseudo-second order kinetics(R^2= 0.999). The equilibrium data were fit to Langmuir and Tempkin models(R^2= 0.999 and 0.997 respectively). The results reveal an exceptional removal for the anionic dye(Alizarin Red S.) with a record adsorption capacity of400 mg·g^(-1). The significantly high adsorption capacity of UiO-66 towards ARS adds further evidence to the recently reported exceptional performance of MOFs in pollutants removal from water.
基金Supported by the National Natural Science Foundation of China(21276174)the Natural Science Foundation of Shanxi Province(2013011040-1)
文摘Inverse emulsion polymerization was employed to synthesize inverse emulsion Cd（Ⅱ） imprinted polymers （IEⅡ P）. The morphology and functional groups of IEⅡP were characterized by SEM,FTIR and TG. Static adsorption experiments and competitive adsorption test were used to evaluate the adsorption ability of IEⅡP. The adsorption capacity of polymers could reach 86.7 mg·g^-1 under the optimal adsorption conditions. The pseudo second order kinetic model and Langmuir isotherm model could be used to analyze the experimental data well. The adsorption process of IEⅡP was chemical adsorption process and monomolecular type. Thermodynamic parameters showed that the adsorption process was endothermic and could occur spontaneously. The selectivity coefficients k of Cd^2＋/v, Cd^2＋/Zn^2＋ and Cd^2＋/Cu^2＋ were 2.4998, 1.2437 and 4.6882, respectively. The proposed method provides a new thought for removing Cd（Ⅱ） in water samples.
文摘Wastewater containing high concentrations of ammonia can be harmful to aquatic life and degrade the water quality. Wastewater containing ammonia is usually removed by conventional methods such as aeration in towers, biological treatment and adsorption of the ammonium ion to the zeolite surface. However, these methods are less effective and relatively expensive. Therefore there is a need for alternative technologies that can improve the efficiency of ammonia removal from wastewater. This study aims to obtain the process of ammonia removal through a combination of absorption in the membrane contactor and the advance oxidation process in the hybrid plasma-ozone reactor. Wastewater containing ammonia used in the study was a synthetic wastewater with a concentration of about 800 ppm. In the experiment, the wastewater fi＇om the reservoir was firstly passed into the membrane contactor on the shell side, and then mixed with ozone from the ozonator befbre entering the plasma reactor, and finally was circulated back to the reservoir. Meanwhile, the absorbent solution was sent to the lumen fiber in membrane contactor. Experimental results showed that the ammonia removal efficiency increases with increasing in circulation rate and temperature of the wastewater. The highest efficiency of ammonia removal obtained from the experimental results was 77%.
文摘The present study demonstrates the potential of the simulation based on-line synthesis, design and optimization strategy for pressure swing adsorption （PSA） processes developed in our earlier study by implementing on an actual two-bed unit. The unit is very flexible and allows process synthesis from the PSA cycle configuration point of view. The model parameters are regressed and updated using live experimental data. The on-line monitoring and controlling of the operating parameters and operating configurations are done by multi-loop processor programmable logic controller. Separation of air into nitrogen free oxygen as raffinate stream and enriched nitrogen as extract stream using 5A zeolite as adsorbent has been chosen as a specific system for implementing the strategy. The philosophy of the typical optimization and process synthesis exercise implemented on the unit is described. The results show the successful implementation of the developed strategy on the two-bed O2-PSA unit and the application of this general approach to commercial PSA processes.
