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Effects of different sludge disintegration methods on sludge moisture distribution and dewatering performance 被引量:13
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作者 Lingyun Jin Guangming Zhang Xiang Zheng 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2015年第2期22-28,共7页
A key step in sludge treatment is sludge dewatering. However, activated sludge is generally very difficult to be dewatered. Sludge dewatering performance is largely affected by the sludge moisture distribution. Sludge... A key step in sludge treatment is sludge dewatering. However, activated sludge is generally very difficult to be dewatered. Sludge dewatering performance is largely affected by the sludge moisture distribution. Sludge disintegration can destroy the sludge structure and cell wall, so as change the sludge floc structure and moisture distribution, thus affecting the dewatering performance of sludge. In this article, the disintegration methods were ultrasound treatment, K2 Fe O4oxidation and KMn O4 oxidation. The degree of disintegration(DDCOD), sludge moisture distribution and the final water content of sludge cake after centrifuging were measured. Results showed that three disintegration methods were all effective, and K2 Fe O4oxidation was more efficient than KMn O4 oxidation. The content of free water increased obviously with K2 Fe O4and KMn O4 oxidations, while it decreased with ultrasound treatment. The changes of free water and interstitial water were in the opposite trend. The content of bounding water decreased with K2 Fe O4oxidation, and increased slightly with KMn O4 oxidation, while it increased obviously with ultrasound treatment. The water content of sludge cake after centrifuging decreased with K2 Fe O4oxidation, and did not changed with KMn O4 oxidation, but increased obviously with ultrasound treatment. In summary, ultrasound treatment deteriorated the sludge dewaterability, while K2 Fe O4and KMn O4 oxidation improved the sludge dewaterability. 展开更多
关键词 Ultrasound treatment K2Fe o4oxidation KMn o4oxidation Sludge moisture distribution Dewatering performance
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Magnetic Fe_3O_4-Reduced Graphene Oxide Nanocomposites-Based Electrochemical Biosensing 被引量:3
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作者 Lili Yu Hui Wu +4 位作者 Beina Wu Ziyi Wang Hongmei Cao Congying Fu Nengqin Jia 《Nano-Micro Letters》 SCIE EI CAS 2014年第3期258-267,共10页
An electrochemical biosensing platform was developed based on glucose oxidase(GOx)/Fe3O4-reduced graphene oxide(Fe3O4-RGO) nanosheets loaded on the magnetic glassy carbon electrode(MGCE).With the advantages of the mag... An electrochemical biosensing platform was developed based on glucose oxidase(GOx)/Fe3O4-reduced graphene oxide(Fe3O4-RGO) nanosheets loaded on the magnetic glassy carbon electrode(MGCE).With the advantages of the magnetism, conductivity and biocompatibility of the Fe3O4-RGO nanosheets, the nanocomposites could be facilely adhered to the electrode surface by magnetically controllable assembling and beneficial to achieve the direct redox reactions and electrocatalytic behaviors of GOx immobilized into the nanocomposites. The biosensor exhibited good electrocatalytic activity, high sensitivity and stability. The current response is linear over glucose concentration ranging from 0.05 to 1.5 m M with a low detection limit of0.15 μM. Meanwhile, validation of the applicability of the biosensor was carried out by determining glucose in serum samples. The proposed protocol is simple, inexpensive and convenient, which shows great potential in biosensing application. 展开更多
关键词 Fe3O4-reduced graphene oxide(Fe3O4-RGO) NANOCOMPOSITES Magnetically controllable assembling Direct electron transfer BIOSENSOR
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Preparation and thermoelectric transport properties of Ba-, La- and Ag- doped Ca3Co4O9 oxide materials 被引量:2
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作者 ZHANG Feipeng LU Qingmei +3 位作者 LITingxian ZHANG Xin ZHANG Jiuxing SONG Xiaoyan 《Journal of Rare Earths》 SCIE EI CAS CSCD 2013年第8期778-783,共6页
The Ba-, La- and Ag-doped polycrystalline Ca2.9M0.1Co4O9 (M=Ca, Ba, La, Ag) thermoelectric bulk samples were pre- pared via citrate acid sol-gel synthesis method followed by spark plasma sintering technique. The bul... The Ba-, La- and Ag-doped polycrystalline Ca2.9M0.1Co4O9 (M=Ca, Ba, La, Ag) thermoelectric bulk samples were pre- pared via citrate acid sol-gel synthesis method followed by spark plasma sintering technique. The bulk samples were characterized and analyzed with regard to their phase compositions, grain orientations as well as microstructures. The high temperature thermoelec- tric transport properties of the bulk samples were studied in detail. All bulk samples were found to be single-phased with modified body texture. The electrical resistivity was modulated as a result of carrier concentration modification, however the carrier transport process was not influenced; the Seebeck coefficient was deteriorated simultaneously. The total thermal conductivity was remarkably reduced, on account of the decreasing of phonon thermal conductivity. The thermoelectric properties of the Ba-, La-, and Ag-doped bulk samples were optimized, and the Ba-doped Ca2.9Ba0.1Co4O9 system was found to have the highest dimensionless figure of merit ZT0.20 at 973 K, which was remarkably higher than that of the un-doped sample. 展开更多
关键词 Ca3Co4O9 oxide Ca-site doping thermoelectric transport properties rare earths
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Sono-assisted preparation of magnetic ferroferric oxide/graphene oxide nanoparticles and application on dye removal 被引量:4
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作者 江国栋 常青 +2 位作者 杨福福 胡晓允 唐和清 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2015年第3期510-515,共6页
A simple ultrasound-assisted co-precipitation method was developed to prepare ferroferric oxide/graphene oxide magnetic nanoparticles(Fe_3O_4/CO MNPs).The hysteresis loop of Fe_3O_4/GO MNPs demonstrated that the sampl... A simple ultrasound-assisted co-precipitation method was developed to prepare ferroferric oxide/graphene oxide magnetic nanoparticles(Fe_3O_4/CO MNPs).The hysteresis loop of Fe_3O_4/GO MNPs demonstrated that the sample was typical of superparamagnetic material.The samples were characterized by transmission electron microscope,and it is found that the particles are of small size.The Fe_3O_4/GO MNPs were further used as an adsorbent to remove Rhodamine B.The effects of initial pH of the solution,the dosage of adsorbent,temperature,contact time and the presence of interfering dyes on adsorption performance were investigated as well.The adsorption equilibrium and kinetics data were fitted well with the Freundlich isotherm and the pseudosecond-order kinetic model respectively.The adsorption process followed intra-particle diffusion model with more than one process affecting the adsorption of Rhodamine B.And the adsorption process was endothermic in nature.Furthermore,the magnetic composite with a high adsorption capacity of Rhodamine B could be effectively and simply separated using an external magnetic field.And the used particles could be regenerated and recycled easily.The magnetic composite could find potential applications for the removal of dye pollutants. 展开更多
关键词 Fe3O4/graphene oxide nanoparticles Sonochemical synthesis Adsorption Kinetic modeling Equilibrium Regeneration
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Highly efficient P uptake by Fe3O4 loaded amorphous Zr-La (carbonate) oxides: Electrostatic attraction, inner-sphere complexation and oxygen vacancies acceleration effect 被引量:3
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作者 Chenyang Liu Yili Wang +5 位作者 Xiaolin Li Junyi Li Shuoxun Dong Haotian Hao Yao Tong Yanqing Zhou 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2022年第10期18-29,共12页
Bimetallic oxides composites have received an increasing attention as promising adsorbents for aqueous phosphate (P) removal in recent years. In this study, a novel magnetic composite MZLCO was prepared by hybridizing... Bimetallic oxides composites have received an increasing attention as promising adsorbents for aqueous phosphate (P) removal in recent years. In this study, a novel magnetic composite MZLCO was prepared by hybridizing amorphous Zr-La (carbonate) oxides (ZLCO) with nano-FeOthrough a one-pot solvothermal method for efficient phosphate adsorption. Our optimum sample of MZLCO-45 exhibited a high Langmuir maximum adsorption capacity of 96.16 mg P/g and performed well even at low phosphate concentration. The phosphate adsorption kinetics by MZLCO-45 fitted well with the pseudo-second-order model, and the adsorption capacity could reach 79% of the ultimate value within the first 60 min. The phosphate adsorption process was highly p H-dependent, and MZLCO-45 performed well over a wide p H range of 2.0-8.0. Moreover, MZLCO-45 showed a strong selectivity to phosphate in the presence of competing ions (Cl^(-), NO_(3)^(-), SO_(4)^(2-), HCO_(3)^(-), Ca^(2+), and Mg^(2+)) and a good reusability using the eluent of Na OH/Na Cl mixture, then 64% adsorption capacity remained after ten recycles. The initial 2.0 mg P/L in municipal wastewater and surface water could be efficiently reduced to below 0.1mg P/L by 0.07 g/L MZLCO-45, and the phosphate removal efficiencies were 95.7% and 96.21%, respectively. Phosphate adsorption mechanisms by MZLCO-45 could be attributed to electrostatic attraction and the inner-sphere complexation via ligand exchange forming Zr/La-O-P, -OH and CO_(3)^(2-)groups on MZLCO-45 surface played important roles in the ligand exchange process. The existence of oxygen vacancies could accelerate the phosphate absorption rate of the MZLCO-45 composites. 展开更多
关键词 Fe3O4 loaded amorphous Zr-La(carbonate)oxides Phosphate adsorption performance Regeneration Mechanism Real water treatment
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Surface magnetization of siderite mineral 被引量:5
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作者 Wu Xiqing Xu Pengyun +2 位作者 Duan Yunfeng Hu Cong Li Guoping 《International Journal of Mining Science and Technology》 SCIE EI 2012年第6期816-821,共6页
Surface self-magnetization of siderite is achieved by generating ferromagnetic substance on the surface of siderite by adjusting slurry temperature,pH value,stirring rate and reaction time.No addition of any iron-cont... Surface self-magnetization of siderite is achieved by generating ferromagnetic substance on the surface of siderite by adjusting slurry temperature,pH value,stirring rate and reaction time.No addition of any iron-containing reagent is required.The temperature of 60 ℃,NaOH concentration of 0.10 mol/L;stirring rate of 900 r/min and the reaction time of 10 min are the optimal conditions.The results show that the siderite recovery in magnetic separation increased from 26.9% to 88.8% after surface magnetization.Magnetization kinetic equation is expressed as 1 [1(e0.269)]1/3 = Kt.Activation energy for the magnetization reaction is 4.30 kJ/mol.VSM,SEM and XPS were used to characterize the siderite,and results show that the saturated magnetization(rs) of siderite increased from 0.652 to 2.569Am2 /kg,the magnetic hysteresis was detected with a coercive force of 0.976 A/m after magnetization;Fe2P3/2 electron binding energy changed which reflects the valence alteration in iron on the surface and the formation of ferromagnetic Fe3O4. 展开更多
关键词 Iron ores Magnetic separation Surface magnetization Air oxidation Fe3O4 chemical synthesis
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Effects of soil moisture and temperature on CH_4 oxidation and N_2O emission of forest soil 被引量:2
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作者 张秀君 徐慧 陈冠雄 《Journal of Forestry Research》 CAS CSCD 2000年第3期203-206,共4页
Soil samples were taken from depth of 0-12cm in the virgin broad- leaved/Korean pine mixed forest in Changbai Mountain in April, 2000. 20 μL·L-1 and 200 μL·L-1 CH4 and N2O concentration were supplied for a... Soil samples were taken from depth of 0-12cm in the virgin broad- leaved/Korean pine mixed forest in Changbai Mountain in April, 2000. 20 μL·L-1 and 200 μL·L-1 CH4 and N2O concentration were supplied for analysis. Laboratory study on CH4 oxidation and N2O emission in forest soil showed that fresh soil sample could oxidize atmospheric methane and product N2O. Air-dried soil sample could not oxidize atmospheric methane, but could produCt N2O. However, it could oxidize the supplied methane quickly when its concentration was higher than 20 μL·L-1. The oxidation rate of methane was increased with its initial concentration. An addition of water to dry soil caused large pulse of N2O emissions within 2 hours. There were curvilinear correlations between N2O emission and temperature (r2=0.706, p <0.05), and between N2O emission andtwater content (r2=0.2968. p <0.05). These suggested temperature and water content were important factors controlling N2O emission. The correlation between CH4 oxidization and temperature was also found while CH4 was supplied 200 μL·L-1 (r2 =0.3573, p<0.05). Temperature was an important f8Ctor controlling CH4 oxidation. However, when 20 μL·L-1 CH4 was supplied, there was no correlation among CH4 oxidization, N2O emission, temperature and water content. 展开更多
关键词 Air-dried soil Fresh forest soil CH_4 oxidation N_2O emission
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Magnetic CuO nanoparticles supported on graphene oxide as an efficient catalyst for A^3-coupling synthesis of propargylamines 被引量:2
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作者 Maryam Mirabedini Elaheh Motamedi Mohammad Zaman Kassaee 《Chinese Chemical Letters》 SCIE CAS CSCD 2015年第9期1085-1090,共6页
Magnetically separable CuO nanoparticles supported on graphene oxide(Fe3O4 NPs/GO-CuO NPs) is synthesized and characterized for the preparation of propargylamines in EtOH,at 90 C.Fe3O4 NPs/GOCuO NPs is found to be a... Magnetically separable CuO nanoparticles supported on graphene oxide(Fe3O4 NPs/GO-CuO NPs) is synthesized and characterized for the preparation of propargylamines in EtOH,at 90 C.Fe3O4 NPs/GOCuO NPs is found to be an efficient catalyst for the A^3-coupling of aldehydes,amines,and alkynes through C-H activation.Both aromatic and aliphatic aldehydes and alkynes are combined with secondary amines to provide a wide range of propargylamines in moderate to excellent yields. 展开更多
关键词 CuO Graphene oxide Fe3O4 A^3-coupling Nano-catalyst Magnetic nanoparticles
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Microwave absorbing characteristics and temperature increasing behavior of basic cobalt carbonate in microwave field
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作者 刘秉国 彭金辉 +4 位作者 张利波 SRINIVASAKANNAN C 黄铭 张泽彪 郭胜惠 《Journal of Central South University》 SCIE EI CAS 2010年第6期1211-1215,共5页
The microwave absorbing characteristics of basic cobalt carbonate,cobalt oxide(Co3O4),and the mixture of basic cobalt carbonate and cobalt oxide were investigated by means of microwave cavity perturbation,their temper... The microwave absorbing characteristics of basic cobalt carbonate,cobalt oxide(Co3O4),and the mixture of basic cobalt carbonate and cobalt oxide were investigated by means of microwave cavity perturbation,their temperature increasing curves were measured,and their ability to absorb microwave energy was also assessed based on the temperature increasing behavior of the material exposed to microwave field.Analyses of spectrum attenuation and relative frequency shift show that basic cobalt carbonate has weak capability to absorb microwave energy,while cobalt oxide has very strong capability to absorb microwave energy.It is feasible to thermally decompose basic cobalt carbonate though addition of small amount of cobalt oxide in microwave fields.The capability to absorb microwave energy of sample increases with an increase in mixing ratio of Co3O4. 展开更多
关键词 basic cobalt carbonate cobalt oxide (Co3O4) MICROWAVE temperature increasing behavior absorption
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Rh_2O_3/monoclinic CePO_4 composite catalysts for N_2O decomposition and CO oxidation
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作者 Huan Liu Zhen Ma 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2018年第1期109-115,共7页
CePO4 (in particular, monoclinic CePO4) has been rarely used to make supported catalysts. Herein, monoclinic CeP04 nanoparticles were prepared by calcining hexagonal CePO4 nanomds (prepared by precipitation) in ai... CePO4 (in particular, monoclinic CePO4) has been rarely used to make supported catalysts. Herein, monoclinic CeP04 nanoparticles were prepared by calcining hexagonal CePO4 nanomds (prepared by precipitation) in air at 900 ℃. Monoclinic CePO4 nanowires were prepared by calcining hexagonal CePO4 nanowires (prepared by hydrothermal synthesis at 150 ℃) in air at 900 ℃. Both monoclinic CePO4 materials were used to support Rh2O3 by impregnation using Rh(NO3)3 as a precursor (followed by calcination). The catalytic performance of Rh2O3/monoclinic CePO4 composite materials in N2O decomposition and CO oxidation was investigated. It was found that Rh2O3 supported on monoclinic CePO4 nanowims was much more active than Rh2O3 supported on monoclinic CePO4 nanoparticles. The stability of catalysts as a function of reaction time on stream was studied in both reactions. The influence of co-fed CO2, O2, and H2O on the catalytic activity in N20 decomposition was also studied. These catalysts were characterized by employing N2 adsorption-desorption, ICP-OES, XRD, TEM, XPS, H2-TPR, O2-TPD, and CO2-TPD. The correlation between physicochemical properties and catalytic properties was discussed. 展开更多
关键词 Rh2O3 CePO4 N2O decomposition CO oxidation Catalyst
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Highly efficient and regioselective thiocyanation of aromatic amines,anisols and activated phenols with H_2O_2/NH_4SCN catalyzed by nanomagnetic Fe_3O_4
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作者 Dariush Khalili 《Chinese Chemical Letters》 SCIE CAS CSCD 2015年第5期547-552,共6页
A new method employing magnetic nanoparticles Fe3O4 as a catalyst and H2O2 as a green oxidant is developed for the oxidative thiocyanation of aromatic amines, anisols and activated phenols with high yields under mild ... A new method employing magnetic nanoparticles Fe3O4 as a catalyst and H2O2 as a green oxidant is developed for the oxidative thiocyanation of aromatic amines, anisols and activated phenols with high yields under mild reaction conditions. The catalyst could be easily recovered from the reaction mixture using an external magnet and reused in several reaction cycles without loss of activity. 展开更多
关键词 Arenes Green oxidant Hydrogen peroxide Nanomagnetic Fe3O4 NH4SCN Thiocyaoation
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