TOC and color in the bleaching effluent from straw pulp paper process could not reach draining standard after its treatment by a biochemical process. In this study, advanced treatment by integrated micro-electrolysis ...TOC and color in the bleaching effluent from straw pulp paper process could not reach draining standard after its treatment by a biochemical process. In this study, advanced treatment by integrated micro-electrolysis （Fe^0） method and Fenton-like process was investigated under various conditions, i.e. pH, Fe/C ratio, initial I-I2O2 concentration and carrier gas. Results showed that Fe/C ratio（V/V = 1.5）, larger H2O2 dosage around 50 rag/L, lower pH（pH= 3） turned out to be particularly efficient. Temperature was a key parameter, remarkably increasing reaction rates. Carrier air not only improved reaction efficiency, but also saved H2O2 dosage. Chlorinated organic compounds could be reductive dechlorinated by Fe^0 reaction and oxidated by OH produced from Fenton process. The combination of Fe^0 and H2O2 reactions had been proved to be highly effective for the advanced treatment of such a type of wastewaters, and important advantages concerning the application in the study.展开更多
g-C_(3)N_(4) coupled with high specific area TiO_(2)(HSA-TiO_(2))composite was prepared by a simple solvothermal method,which was easy to operate with low energy consumption.Degradation of methyl orange test results s...g-C_(3)N_(4) coupled with high specific area TiO_(2)(HSA-TiO_(2))composite was prepared by a simple solvothermal method,which was easy to operate with low energy consumption.Degradation of methyl orange test results showed that HSA-TiO_(2) effectively improved the photocatalytic activity effectively.Photoelectrochemical test results indicated that the separation of photo-generated carriers and the charge carrier migration speed of TiO_(2) were improved after combination with g-C_(3)N_(4).g-C3N4/HSA-TiO_(2) showed strong photocatalytic ability.The degree of degradation of methyl orange by 6%-g-C_(3)N_(4)/HSA-TiO_(2) could reach up to 92.44%.Furthermore,it revealed good cycle performance.The photocatalytic mechanism of g-C_(3)N_(4)/HSA-TiO_(2) was proposed.展开更多
The mechanism of the action of copper-dependent quercetin 2,3-dioxygenase （2,3QD） has been investigated by means of hy- brid density functional theory. The 2,3QD enzyme cleaves the O-heterocycle of a quercetin by in...The mechanism of the action of copper-dependent quercetin 2,3-dioxygenase （2,3QD） has been investigated by means of hy- brid density functional theory. The 2,3QD enzyme cleaves the O-heterocycle of a quercetin by incorporation of both oxygen atoms into the substrate and releases carbon monoxide. The calculations show that dioxygen attack on the copper complex is energetically favorable. The adduct has a possible near-degeneracy of states between [Cu2＋-（substrate H＋）] and [Cu＋-（sub- strate-H）. ], and in addition the pyramidalized C2 atom is ideally suited for forming a dioxygembridged structure. In the next step, the C3-C4 bond is cleaved and intermediate lnt5 is formed via transition state TS4. Finally, the Oa-Ob and C2-C3 bonds are cleaved, and CO is released in one concerted transition state （TS5） with the barrier of 63.25 and 61.91 k J/tool in the gas phase and protein environments, respectively. On the basis of our proposed reaction mechanism, this is the rate-limiting step of the whole catalytic cycle and is strongly driven by a relatively large exothermicity of 100.86 kJ/mol. Our work provides some valuable fundamental insights into the behavior of this enzyme.展开更多
文摘TOC and color in the bleaching effluent from straw pulp paper process could not reach draining standard after its treatment by a biochemical process. In this study, advanced treatment by integrated micro-electrolysis （Fe^0） method and Fenton-like process was investigated under various conditions, i.e. pH, Fe/C ratio, initial I-I2O2 concentration and carrier gas. Results showed that Fe/C ratio（V/V = 1.5）, larger H2O2 dosage around 50 rag/L, lower pH（pH= 3） turned out to be particularly efficient. Temperature was a key parameter, remarkably increasing reaction rates. Carrier air not only improved reaction efficiency, but also saved H2O2 dosage. Chlorinated organic compounds could be reductive dechlorinated by Fe^0 reaction and oxidated by OH produced from Fenton process. The combination of Fe^0 and H2O2 reactions had been proved to be highly effective for the advanced treatment of such a type of wastewaters, and important advantages concerning the application in the study.
基金supported by the National Natural Science Foundation of China(No.61308095,No.21801092,and No.11904128)the Program for the Development of Science and Technology of Jilin province(No.20180520002JH)+1 种基金the Graduate Innovation Project of Jilin Normal University(No.201941)the Key Research Programs in Universities of Henan Province(20A150031).
文摘g-C_(3)N_(4) coupled with high specific area TiO_(2)(HSA-TiO_(2))composite was prepared by a simple solvothermal method,which was easy to operate with low energy consumption.Degradation of methyl orange test results showed that HSA-TiO_(2) effectively improved the photocatalytic activity effectively.Photoelectrochemical test results indicated that the separation of photo-generated carriers and the charge carrier migration speed of TiO_(2) were improved after combination with g-C_(3)N_(4).g-C3N4/HSA-TiO_(2) showed strong photocatalytic ability.The degree of degradation of methyl orange by 6%-g-C_(3)N_(4)/HSA-TiO_(2) could reach up to 92.44%.Furthermore,it revealed good cycle performance.The photocatalytic mechanism of g-C_(3)N_(4)/HSA-TiO_(2) was proposed.
基金supported by the National Natural Science Foundation of China (21073164,20673098)the Natural Science Foundation of Zhejiang Province (Y4100620)the Research Foundation of the Education Bureau of Zhejiang Province (Y200906517)
文摘The mechanism of the action of copper-dependent quercetin 2,3-dioxygenase （2,3QD） has been investigated by means of hy- brid density functional theory. The 2,3QD enzyme cleaves the O-heterocycle of a quercetin by incorporation of both oxygen atoms into the substrate and releases carbon monoxide. The calculations show that dioxygen attack on the copper complex is energetically favorable. The adduct has a possible near-degeneracy of states between [Cu2＋-（substrate H＋）] and [Cu＋-（sub- strate-H）. ], and in addition the pyramidalized C2 atom is ideally suited for forming a dioxygembridged structure. In the next step, the C3-C4 bond is cleaved and intermediate lnt5 is formed via transition state TS4. Finally, the Oa-Ob and C2-C3 bonds are cleaved, and CO is released in one concerted transition state （TS5） with the barrier of 63.25 and 61.91 k J/tool in the gas phase and protein environments, respectively. On the basis of our proposed reaction mechanism, this is the rate-limiting step of the whole catalytic cycle and is strongly driven by a relatively large exothermicity of 100.86 kJ/mol. Our work provides some valuable fundamental insights into the behavior of this enzyme.
