In this paper, a pulsed discharge plasma （PDP） system with a multi-needle-to-plate electrodes geometry was set up to investigate the regeneration of acid orange 7 （AO7） exhausted granular activated carbon （GAC）....In this paper, a pulsed discharge plasma （PDP） system with a multi-needle-to-plate electrodes geometry was set up to investigate the regeneration of acid orange 7 （AO7） exhausted granular activated carbon （GAC）. Regeneration of GAC was studied under different conditions of peak pulse discharge voltage and water pH, as well as the modification effect of GAC by the pulse discharge process, to figure out the regeneration efficiency and the change of the GAC structure by the PDP treatment. The obtained results showed that there was an appropriate peak pulse voltage and an optimal initial pH value of the solution for GAC regeneration. Analyses of scanning electron microscope （SEM）, Boehm titration, Brunauer-Emmett-Teller （BET）, Horvath-Kawazoe （HK）, and X-ray Diffraction （XRD） showed that there were more mesopore and macropore in the regenerated GAC and the structure turned smoother with the increase of discharge voltage; the amount of acidic functional groups on the GAC surface increased while the amount of basic functional groups decreased after the regeneration process. From the result of the XRD analysis, there were no new substances produced on the GAC after PDP treatment.展开更多
Bottom ash. a power plant waste, was used to adsorb acid orange 7. The adsorption of acid orange 7 in aqueous solutions onto bottom ash was studied as functions of particle size. dosage, initial concentration and agit...Bottom ash. a power plant waste, was used to adsorb acid orange 7. The adsorption of acid orange 7 in aqueous solutions onto bottom ash was studied as functions of particle size. dosage, initial concentration and agitation time by batch experiments. Under conditions of bottom ash dosage of 1.5 g/50 ml and 5 g/50 ml for 〈0.074 mm and 0.074 mm-0.2 mm of bottom ash, respectively, it could achieve 99.1% and 87.6% dye removal efficiency. The adsorption isotherms for the bottom ash could be well described by both Freundlich and Langmuir isotherms. The calculated dye adsorption capacities of bottom ash for the particle size of 0.074 mm -0.2 mm and 〈0.074 mm were 2.78 mg/g and 10.21 mg/g, respectively. The results indicated that the dye uptake process fitted to the pseudo-first-order kinetic model better than the pseudo-second-order. The data were also fitted to intraparticle diffusion model by two adsorption stages, due to the difference in rate of mass transfer in the initial and final stages of adsorption. Significant variations were observed in the FTIR spectra and Stem photographs of bottom ash after adsorption. The column parameters were calculated by breakthrough curves at different flow rates and bed depths.展开更多
基金supported by National Natural Science Foundation of China(No.21207052)China Postdoctoral Science Foundation(No.20110491353)Jiangsu Planned Projects for Postdoctoral Research Funds,China(No.1102116C)
文摘In this paper, a pulsed discharge plasma （PDP） system with a multi-needle-to-plate electrodes geometry was set up to investigate the regeneration of acid orange 7 （AO7） exhausted granular activated carbon （GAC）. Regeneration of GAC was studied under different conditions of peak pulse discharge voltage and water pH, as well as the modification effect of GAC by the pulse discharge process, to figure out the regeneration efficiency and the change of the GAC structure by the PDP treatment. The obtained results showed that there was an appropriate peak pulse voltage and an optimal initial pH value of the solution for GAC regeneration. Analyses of scanning electron microscope （SEM）, Boehm titration, Brunauer-Emmett-Teller （BET）, Horvath-Kawazoe （HK）, and X-ray Diffraction （XRD） showed that there were more mesopore and macropore in the regenerated GAC and the structure turned smoother with the increase of discharge voltage; the amount of acidic functional groups on the GAC surface increased while the amount of basic functional groups decreased after the regeneration process. From the result of the XRD analysis, there were no new substances produced on the GAC after PDP treatment.
基金Acknowledgements： The study was supported by the National Natural Science Foundation of China （No. 40501063）.
文摘Bottom ash. a power plant waste, was used to adsorb acid orange 7. The adsorption of acid orange 7 in aqueous solutions onto bottom ash was studied as functions of particle size. dosage, initial concentration and agitation time by batch experiments. Under conditions of bottom ash dosage of 1.5 g/50 ml and 5 g/50 ml for 〈0.074 mm and 0.074 mm-0.2 mm of bottom ash, respectively, it could achieve 99.1% and 87.6% dye removal efficiency. The adsorption isotherms for the bottom ash could be well described by both Freundlich and Langmuir isotherms. The calculated dye adsorption capacities of bottom ash for the particle size of 0.074 mm -0.2 mm and 〈0.074 mm were 2.78 mg/g and 10.21 mg/g, respectively. The results indicated that the dye uptake process fitted to the pseudo-first-order kinetic model better than the pseudo-second-order. The data were also fitted to intraparticle diffusion model by two adsorption stages, due to the difference in rate of mass transfer in the initial and final stages of adsorption. Significant variations were observed in the FTIR spectra and Stem photographs of bottom ash after adsorption. The column parameters were calculated by breakthrough curves at different flow rates and bed depths.
文摘该文探究了UV与过碳酸钠(SPC)均相高级氧化体系去除酸性橙7(AO7)的反应机理。结果表明:当AO7初始浓度为20 mg/L、SPC投加量为0.5 mmol/L时,光解25 min时AO7去除率可达98.4%,反应过程符合一级反应动力学模型,R^(2)>0.990。当pH约为3.0时,25 min AO7去除率为74.2%,当pH值提高至10.0左右时,体系去除效率提升至99.8%。高浓度无机阴离子HCO_(3)^(-)和NO_(3)^(-)均会对体系产生抑制,低浓度Cl-轻微促进,而SO_(4)^(2-)对反应速率几乎无影响。腐殖酸对AO7降解抑制相对较强,印染助剂柠檬酸钠对体系影响较小。自由基捕获实验和电子顺磁共振测试结果表明,UV/SPC体系中的活性物质为·OH、·CO_(3)^(-)、^(1)O_(2)和O_(2)^(•-),·OH为主要活性自由基。TOC结果表明,60 min TOC去除率为41.8%,具有比UV/H_(2)O_(2)更好的矿化效果。UV-Vis吸收光谱分析表明,16 min左右时主特征峰接近完全消失。依据液相色谱-质谱联用仪实验结果提出了AO7在UV/SPC高级氧化体系降解过程中的可能转化途径。
