This work presents a study for chemical leaching of sphalerite concentrate under various constant Fe3+ concentrations and redox potential conditions. The effects of Fe3+ concentration and redox potential on chemical l...This work presents a study for chemical leaching of sphalerite concentrate under various constant Fe3+ concentrations and redox potential conditions. The effects of Fe3+ concentration and redox potential on chemical leaching of sphalerite were investigated. The shrinking core model was applied to analyze the experimental results. It was found that both the Fe3+ concentration and the redox potential controlled the chemical leaching rate of sphalerite. A new kinetic model was developed, in which the chemical leaching rate of sphalerite was proportional to Fe3+ concentration and Fe3+ /Fe2+ ratio. All the model parameters were evaluated from the experimental data. The model predictions fit well with the experimental observed values.展开更多
The aim of this work is to evaluate the feasibility of applying the technology of oxidation-reduction potential （ORP） control on the municipal wastewater treatment system for nitrogen and phosphorus removal. Meanwhi...The aim of this work is to evaluate the feasibility of applying the technology of oxidation-reduction potential （ORP） control on the municipal wastewater treatment system for nitrogen and phosphorus removal. Meanwhile the relation between the optimal ORP （ ORPopt ） and influent C/N ratio was evaluated, in which the influent chemical oxygen demand （ COD ） concentration was stabilized at （290 ± 10 ） mg/L, the influent total phosphorus （TP） concentration was stabilized at （7.0 ± 0.5 ） mg/L. The results indicated that： （1） the ORP in the second anoxic zone had effect on nitrogen and phosphorus removal capability, and the average percentages of phosphorus uptake in ANO2 zone （ ηa ） increased with increasing ORP, i. e. , increasing from 12. 0% at - 143 mV to 22.0%,30.0%,37.0%, and45.0% at -123, -111, -105 and -95 mV, respectively; （2） the ORPopt as function of influent C/N ratio could be calculated by the equation： y ffi 252. 73e〈 -x/3.39） _ 131.01 ; the maximum percentage of phosphorus uptake in ANO2 as function of the ORPopt could be calculated by the equation： y ffi -0.49e（x/15.58） ＋ 1. 51. The ORPopt was the important process control parameter that must be optimized for operation of enhanced biological phosphorus removal （ EBPR ） system. Moreover, ORP sensor is very simple, and the industrial applications of this strategy is practical.展开更多
Controlling the biogas fermentation process is the key for maintaining stable operation of biogas system and increasing gas yield. Aiming at features of biogas fermentation process and difficulties of control, a pract...Controlling the biogas fermentation process is the key for maintaining stable operation of biogas system and increasing gas yield. Aiming at features of biogas fermentation process and difficulties of control, a practical control scheme is proposed combining the abundant experience of biogas experts. And it discussed the structural design and hardware configuration of the expert control system, established the database and role base, and designed the control strategy of production system inference. The design scheme with ZigBee and PDA technology as core is employed so as to solve problems of environmental factor detection and data transfer management. The test result shows that the deviation of temperature is controlled within ± 0.9℃, the deviation of pH is controlled within ±0.3, the deviation of oxidation-reduction potential is controlled within ±30mV, the deviation of gas production is controlled within ± 9mL and that of methane concentration is controlled within ±4.5%. This system is easily expandable and applicable to biogas engineering at various scales.展开更多
Tailoring tire pore structure and surface chemistry of graphene-based laminates is essentially important for their applications as separation membranes. Usually, pure graphene oxide （GO） and completely reduced GO （...Tailoring tire pore structure and surface chemistry of graphene-based laminates is essentially important for their applications as separation membranes. Usually, pure graphene oxide （GO） and completely reduced GO （rGO） membranes suffer florn low water permeance because of the lack of pristine graphitic sp2 domains and very small interlayer spacing, respectively. In this work, we studied the influence of reduction degree on the structure and separation pertornrance of rGO membranes, tt was found that weak reduction retains the good dispersion and hydrophilicity of GO nanosheets. More importantly, it increases the number of pristine graphitic sp2 domains in rGO nanosheets while keeping the large interlayer spacing of the GO membranes in most regions at the same time. The resultant mernbranes show a high water permeance of 56.3 L m^-2 h^ -1 bar^ -1, which is about 4 times and over 10^4 times larger tban those of the GO and completely reduced rGO membranes, respectively, and high rejection over 95700 for various dyes. Furthermore, they show better structure stability and more superior separation perfor- mance than GO membranes in acid and alkali environments.展开更多
Rational engineering of oxygen vacancy(VO) at atomic precision is the key to comprehensively understanding the oxygen chemistry of oxide materials for catalytic oxidations. Here, we demonstrate that VO can be spatiall...Rational engineering of oxygen vacancy(VO) at atomic precision is the key to comprehensively understanding the oxygen chemistry of oxide materials for catalytic oxidations. Here, we demonstrate that VO can be spatially confined on the surface through a sophisticated surface hydrogen bond(HB) network.The HB network is constructed between a hydroxyl-rich Bi OCl surface and polyprotic phosphoric acid,which remarkably decreases the formation energy of surface VO by selectively weakening the metal–oxygen bonds in a short range. Thus, surface-confined VO enables us to unambiguously distinguish the intrafacial and suprafacial oxygen species associated with NO oxidation in two classical catalytic systems.Unlike randomly distributed bulk VO that benefits the thermocatalytic NO oxidation and lattice O diffusion by the dominant intrafacial mechanism, surface VOis demonstrated to favor the photocatalytic NO oxidation through a suprafacial scheme by energetically activating surface O2, which should be attributed to the spatial confinement nature of surface VO.展开更多
基金Supported by the National Basic Research Program （2010CB630902, 2004CB619202） the National Natural Science Foundation of China （31070034, 30800011, 31260396）+1 种基金 the Knowledge Innovation Program of CAS （2AKSCX2-YW-JS401） the Reward Fund for Young Scientists of Shandong Province （2007BS08002） of China
文摘This work presents a study for chemical leaching of sphalerite concentrate under various constant Fe3+ concentrations and redox potential conditions. The effects of Fe3+ concentration and redox potential on chemical leaching of sphalerite were investigated. The shrinking core model was applied to analyze the experimental results. It was found that both the Fe3+ concentration and the redox potential controlled the chemical leaching rate of sphalerite. A new kinetic model was developed, in which the chemical leaching rate of sphalerite was proportional to Fe3+ concentration and Fe3+ /Fe2+ ratio. All the model parameters were evaluated from the experimental data. The model predictions fit well with the experimental observed values.
基金National Natural Science Foundation of China(NSFC)(No.50978118)
文摘The aim of this work is to evaluate the feasibility of applying the technology of oxidation-reduction potential （ORP） control on the municipal wastewater treatment system for nitrogen and phosphorus removal. Meanwhile the relation between the optimal ORP （ ORPopt ） and influent C/N ratio was evaluated, in which the influent chemical oxygen demand （ COD ） concentration was stabilized at （290 ± 10 ） mg/L, the influent total phosphorus （TP） concentration was stabilized at （7.0 ± 0.5 ） mg/L. The results indicated that： （1） the ORP in the second anoxic zone had effect on nitrogen and phosphorus removal capability, and the average percentages of phosphorus uptake in ANO2 zone （ ηa ） increased with increasing ORP, i. e. , increasing from 12. 0% at - 143 mV to 22.0%,30.0%,37.0%, and45.0% at -123, -111, -105 and -95 mV, respectively; （2） the ORPopt as function of influent C/N ratio could be calculated by the equation： y ffi 252. 73e〈 -x/3.39） _ 131.01 ; the maximum percentage of phosphorus uptake in ANO2 as function of the ORPopt could be calculated by the equation： y ffi -0.49e（x/15.58） ＋ 1. 51. The ORPopt was the important process control parameter that must be optimized for operation of enhanced biological phosphorus removal （ EBPR ） system. Moreover, ORP sensor is very simple, and the industrial applications of this strategy is practical.
文摘Controlling the biogas fermentation process is the key for maintaining stable operation of biogas system and increasing gas yield. Aiming at features of biogas fermentation process and difficulties of control, a practical control scheme is proposed combining the abundant experience of biogas experts. And it discussed the structural design and hardware configuration of the expert control system, established the database and role base, and designed the control strategy of production system inference. The design scheme with ZigBee and PDA technology as core is employed so as to solve problems of environmental factor detection and data transfer management. The test result shows that the deviation of temperature is controlled within ± 0.9℃, the deviation of pH is controlled within ±0.3, the deviation of oxidation-reduction potential is controlled within ±30mV, the deviation of gas production is controlled within ± 9mL and that of methane concentration is controlled within ±4.5%. This system is easily expandable and applicable to biogas engineering at various scales.
基金supported by the National Key Research and Development Program of China(2016YFA0200101)the National Natural Science Foundation of China(51325205,51290273,and51521091)Chinese Academy of Sciences(KGZD-EW-303-1,KGZDEW-T06,174321KYSB20160011,and XDPB06)
文摘Tailoring tire pore structure and surface chemistry of graphene-based laminates is essentially important for their applications as separation membranes. Usually, pure graphene oxide （GO） and completely reduced GO （rGO） membranes suffer florn low water permeance because of the lack of pristine graphitic sp2 domains and very small interlayer spacing, respectively. In this work, we studied the influence of reduction degree on the structure and separation pertornrance of rGO membranes, tt was found that weak reduction retains the good dispersion and hydrophilicity of GO nanosheets. More importantly, it increases the number of pristine graphitic sp2 domains in rGO nanosheets while keeping the large interlayer spacing of the GO membranes in most regions at the same time. The resultant mernbranes show a high water permeance of 56.3 L m^-2 h^ -1 bar^ -1, which is about 4 times and over 10^4 times larger tban those of the GO and completely reduced rGO membranes, respectively, and high rejection over 95700 for various dyes. Furthermore, they show better structure stability and more superior separation perfor- mance than GO membranes in acid and alkali environments.
基金the National Key Research and Development Program of China (2016YFA0203000)National Natural Science Funds for Distinguished Young Scholars (21425728)+2 种基金the National Natural Science Foundation of China (21872061)111 Project (B17019)Self-Determined Research Funds of CCNU from the Colleges’ Basic Research and Operation of MOE (CCNU16A02029)。
文摘Rational engineering of oxygen vacancy(VO) at atomic precision is the key to comprehensively understanding the oxygen chemistry of oxide materials for catalytic oxidations. Here, we demonstrate that VO can be spatially confined on the surface through a sophisticated surface hydrogen bond(HB) network.The HB network is constructed between a hydroxyl-rich Bi OCl surface and polyprotic phosphoric acid,which remarkably decreases the formation energy of surface VO by selectively weakening the metal–oxygen bonds in a short range. Thus, surface-confined VO enables us to unambiguously distinguish the intrafacial and suprafacial oxygen species associated with NO oxidation in two classical catalytic systems.Unlike randomly distributed bulk VO that benefits the thermocatalytic NO oxidation and lattice O diffusion by the dominant intrafacial mechanism, surface VOis demonstrated to favor the photocatalytic NO oxidation through a suprafacial scheme by energetically activating surface O2, which should be attributed to the spatial confinement nature of surface VO.
