The sorption of the uranium(VI) ions from aqueous solutions by diethylethanolammonium organovolcanics(Kula-TURKEY) was investigated under different experimental conditions. DEEA was used to modify the surface of basal...The sorption of the uranium(VI) ions from aqueous solutions by diethylethanolammonium organovolcanics(Kula-TURKEY) was investigated under different experimental conditions. DEEA was used to modify the surface of basaltic volcanics. The characteristic of basaltic volcanic was analyzed by XRF, SEM–EDS, FTIR, and XRD. The BET surface areas of unmodified volcanics and DEEA-modified volcanics were found as 2.265 and3.689 m^2/g, respectively. The volcanic samples were treated by using different concentrations of DEEA. The adsorption of U(VI) on natural and modified volcanics was examined as a function of the contact time, initial p H of the solution, initial U(VI) concentration, and temperature.Langmuir, Freundlich, and D–R adsorption isotherms were used to describe the adsorption. While examining the adsorption percentage and distribution coefficient, these values for unmodified volcanics were found to be25% ± 0.76 and 10.08 m L/g, while the values for the DEEA-modified volcanics were 88% ± 1.04 and 220 m L/g, respectively. The pseudo-first-order and pseudo-secondorder kinetic models were used to describe the kinetic data.In this study, it can be seen that the adsorption process is suitable for the pseudo-second-order kinetic model. Various thermodynamic parameters(ΔG°, ΔH°, and ΔS°) were calculated with the thermodynamic distribution coefficients obtained at different temperatures. The sorption process was a chemical adsorption process. The results indicated that the processes are spontaneous and endothermic.展开更多
Chemical absorption is a crucial step for several chemical processes such as ammonia production, coal gasification, methane reforming,ethylene oxide manufacturing and treatment of associated gas streams [1]. It is con...Chemical absorption is a crucial step for several chemical processes such as ammonia production, coal gasification, methane reforming,ethylene oxide manufacturing and treatment of associated gas streams [1]. It is considered one of the main processes to eliminate CO_2 emissions from power plants by post-combustion.Use of new solvents are of high interest in chemical absorption for carbon capture. For the design of the absorption and desorption columns it is essential to know the vapour-liquid equilibrium(VLE), heat of absorption and densities. N,N-diethylethanolamine(DEEA) appeared as one of the amines with the lowest amount of energy needed for its regeneration [2], which would directly decrease the operation costs. DEEA has a high CO_2 loading of 1 mol/mol of amine compared to the traditional MEA solvent(0.5 mol/mol amine) and is obtained from renewable sources[1]. The main weakness is its low absorption rate and consequently the use of promoters is desirable.In this work, a thermodynamic model based on the electrolyte non-random two-liquid theory(eNRTL) was created and fitted to correlate and predict the partial and total pressures of the unloaded and loaded aqueous DEEA solutions. New interaction parameters were obtained for the binary and tertiary system. This model represents the vapour pressures of the pure components, DEEA and H_2 O, with AARD of 1.9% and 1.73%respectively. Furthermore, the fitted model predicts the total pressure above the binary system, H_2O-DEEA, with AARD of 0.05%. The excess of enthalpy and densities are predicted with AARD of 5.63% and 1.38% respectively. The tertiary system, H_2O-DEEA-CO_2, is fitted for 2 M and5 M DEEA solutions with loading between 0.042 and 0.9 mol CO_2/mol amine up to 80 ℃. Results of CO_2 partial pressures and total pressures are reproduced, with AARD of 19.45% and 16.18% respectively. Densities are predicted with an AARD of 1.52%.展开更多
基金supported by the Manisa Celal Bayar University(No.BAP 2012-005)
文摘The sorption of the uranium(VI) ions from aqueous solutions by diethylethanolammonium organovolcanics(Kula-TURKEY) was investigated under different experimental conditions. DEEA was used to modify the surface of basaltic volcanics. The characteristic of basaltic volcanic was analyzed by XRF, SEM–EDS, FTIR, and XRD. The BET surface areas of unmodified volcanics and DEEA-modified volcanics were found as 2.265 and3.689 m^2/g, respectively. The volcanic samples were treated by using different concentrations of DEEA. The adsorption of U(VI) on natural and modified volcanics was examined as a function of the contact time, initial p H of the solution, initial U(VI) concentration, and temperature.Langmuir, Freundlich, and D–R adsorption isotherms were used to describe the adsorption. While examining the adsorption percentage and distribution coefficient, these values for unmodified volcanics were found to be25% ± 0.76 and 10.08 m L/g, while the values for the DEEA-modified volcanics were 88% ± 1.04 and 220 m L/g, respectively. The pseudo-first-order and pseudo-secondorder kinetic models were used to describe the kinetic data.In this study, it can be seen that the adsorption process is suitable for the pseudo-second-order kinetic model. Various thermodynamic parameters(ΔG°, ΔH°, and ΔS°) were calculated with the thermodynamic distribution coefficients obtained at different temperatures. The sorption process was a chemical adsorption process. The results indicated that the processes are spontaneous and endothermic.
基金financial support of the EPSRC grant EP/J020184/1the UKCCS Research Centre (www.ukccsrc.ac.uk)funded by the EPSRC as part of the RCUK Energy Programme(EP/K000446/1)
文摘Chemical absorption is a crucial step for several chemical processes such as ammonia production, coal gasification, methane reforming,ethylene oxide manufacturing and treatment of associated gas streams [1]. It is considered one of the main processes to eliminate CO_2 emissions from power plants by post-combustion.Use of new solvents are of high interest in chemical absorption for carbon capture. For the design of the absorption and desorption columns it is essential to know the vapour-liquid equilibrium(VLE), heat of absorption and densities. N,N-diethylethanolamine(DEEA) appeared as one of the amines with the lowest amount of energy needed for its regeneration [2], which would directly decrease the operation costs. DEEA has a high CO_2 loading of 1 mol/mol of amine compared to the traditional MEA solvent(0.5 mol/mol amine) and is obtained from renewable sources[1]. The main weakness is its low absorption rate and consequently the use of promoters is desirable.In this work, a thermodynamic model based on the electrolyte non-random two-liquid theory(eNRTL) was created and fitted to correlate and predict the partial and total pressures of the unloaded and loaded aqueous DEEA solutions. New interaction parameters were obtained for the binary and tertiary system. This model represents the vapour pressures of the pure components, DEEA and H_2 O, with AARD of 1.9% and 1.73%respectively. Furthermore, the fitted model predicts the total pressure above the binary system, H_2O-DEEA, with AARD of 0.05%. The excess of enthalpy and densities are predicted with AARD of 5.63% and 1.38% respectively. The tertiary system, H_2O-DEEA-CO_2, is fitted for 2 M and5 M DEEA solutions with loading between 0.042 and 0.9 mol CO_2/mol amine up to 80 ℃. Results of CO_2 partial pressures and total pressures are reproduced, with AARD of 19.45% and 16.18% respectively. Densities are predicted with an AARD of 1.52%.
文摘以多氯联苯（Polychlorinated biphenyls,PCBs）中氯代饱和度最高的十氯联苯（Deca-chlorobiphenyl,D10CB）为对象,考察了反应温度、供氧量、停留时间和Na OH对十氯联苯降解效果和PCBs产物分布的影响,并通过产物的GC-MS检测结果,推测了D10CB的降解机理.实验表明,在供氧量50 m L条件下反应10 min,350~450℃时,D10CB去除率均高于96%,总PCBs的去除率为77.2%~81.2%.供氧量的增加有助于提高PCBs去除率,450℃时,供氧量200 m L比无氧条件下提高了10.5%.Na OH的加入不仅明显提高了D10CB和总PCBs的去除率,而且使产物不同氯代水平PCBs含量分布趋于均匀.结合产物中其他小分子有机组分推测,D10CB超（亚）临界水降解首先发生脱氯反应,继而发生苯环开环、小分子基团去除及氧化分解等复杂反应.
