期刊文献+
共找到849篇文章
< 1 2 43 >
每页显示 20 50 100
High-performance ZIF-8 membranes:preparation and their uranium adsorption performance
1
作者 CUI Shuaichuan DENG Ziqi +6 位作者 HUANG Yifan LIU Shihan WANG Xingxing CHEN Shusen LI Ziming ZHANG Yifan DENG Pengyang 《辐射研究与辐射工艺学报》 CAS CSCD 2024年第5期24-37,共14页
In this study,the ZIF-8 membrane(ZIF-8/PP-g-MAH)is prepared by in situ synthesis of ZIF-8 on irradiation-pretreated polymer substrates to improve the uranium adsorption performance and address the recycling problems o... In this study,the ZIF-8 membrane(ZIF-8/PP-g-MAH)is prepared by in situ synthesis of ZIF-8 on irradiation-pretreated polymer substrates to improve the uranium adsorption performance and address the recycling problems of ZIF-8 powder.The effects of pH,contact time,and uranium concentration on the adsorption of ZIF-8/PP-g-MAH were investigated.Adsorption isotherm and kinetics analysis show that ZIF-8/PP-g-MAH has a high adsorption capacity of 478.5 mg/g,which is 1.26 times higher than that of ZIF-8,and a rapid adsorption equilibrium of 120 min,which is shortened to one-third of that required for ZIF-8(360 min).The adsorption process of ZIF-8/PP-g-MAH is consistent with that of the Langmuir isotherm and pseudo-second-order dynamic model.ZIF-8/PP-g-MAH also exhibits good selectivity for uranium in simulated seawater.The high adsorption performance of ZIF-8/PP-g-MAH is attributed to its membrane structure,which improves the utilization of coordination sites,including Zn-OH,C-N,and C=N.This study provides an efficient adsorption material for rapid uranium extraction,thus promoting the development of uranium extraction technologies. 展开更多
关键词 ZIF-8 Membrane uranium adsorption
下载PDF
Effective Elimination of Hazardous Chromium (VI) Using Periodic Elements and Contemporary Adsorption Methods by Using Magnesium Ferrite Nanoparticle: A Review
2
作者 Nazmun Nahar Mahabub Hossain Swaron +1 位作者 Md. Aliuzzaman Sheik Md. Jamal Uddin 《Journal of Environmental Protection》 2024年第5期596-619,共24页
A well-known hazardous metal and top contaminant in wastewater is hexavalent chromium. The two forms of most commonly found chromium are chromate ( CrO 4 2− ) and dichromate ( Cr 2 O 7 2− ). Leather tanning, cooling t... A well-known hazardous metal and top contaminant in wastewater is hexavalent chromium. The two forms of most commonly found chromium are chromate ( CrO 4 2− ) and dichromate ( Cr 2 O 7 2− ). Leather tanning, cooling tower blow-down, plating, electroplating, rinse water sources, anodizing baths etc. are the main sources of Cr (VI) contamination. The Cr (VI) is not only non-biodegradable in the environment but also carcinogenic to living population. It is still difficult to treat Cr contaminated waste water effectively, safely, eco-friendly, and economically. As a result, many techniques have been used to treat Cr (VI)-polluted wastewater, including adsorption, chemical precipitation, coagulation, ion-exchange, and filtration. Among these practices, the most practical method is adsorption for the removal of Cr (VI) from aqueous solutions, which has gained widespread acceptance due to the ease of use and affordability of the equipment and adsorbent. It has been revealed that Fe-based adsorbents’ oxides and hydroxides have high adsorptive potential to lower Cr (VI) content below the advised threshold. Fe-based adsorbents were also discovered to be relatively cheap and toxic-free in Cr (VI) treatment. Fe-based adsorbents are commonly utilized in industry. It has been discovered that nanoparticles of Fe-, Ti-, and Cu-based adsorbents have a better capacity to remove Cr (VI). Cr (VI) was effectively removed from contaminated water using mixed element-based adsorbents (Fe-Mn, Fe-Ti, Fe-Cu, Fe-Zr, Fe-Cu-Y, Fe-Mg, etc.). Initial findings suggest that Cr (VI) removal from wastewater may be accomplished by using magnesium ferrite nanomaterials as an efficient adsorbent. 展开更多
关键词 Chromium (vi) Periodic Elements adsorption ELIMINATION Magnesium Ferrite
下载PDF
Interaction between uranium and humic acid(Ⅰ):Adsorption behaviors of U(Ⅵ) in soil humic acids 被引量:4
3
作者 WEI Min LIAO Jiali +5 位作者 LIU Ning ZHANG Dong KANG Houjun YANG Yuanyou YANG Yong JIN Jiannan 《Nuclear Science and Techniques》 SCIE CAS CSCD 2007年第5期287-293,共7页
The adsorption behaviors of uranium on three soil humic acids (HAs), which were extracted from soils of different depths at the same site, were investigated under various experimental conditions. The adsorption result... The adsorption behaviors of uranium on three soil humic acids (HAs), which were extracted from soils of different depths at the same site, were investigated under various experimental conditions. The adsorption results showed that U(Ⅵ) in solutions can be adsorbed by the three soil HAs, with the order of FHA (HA from 5 m depth of soil) >SHA (HA from the surface) >THA (HA from 10 m depth of soil) for adsorption efficiency in each desirable condition, and the adsorption reached equilibrium in about 240 min. Although the maximum adsorption efficiency was achieved at a suitable uranium concentration (10 mg·L-1 U(Ⅵ) for SHA and THA, 20 mg·L-1 U(Ⅵ) for FHA), the adsorption could be described with Langmiur isotherm or Freundlich isotherm equation. The L/S (liquid/solid, mL/g) ratio and pH were important factors influencing the adsorption in our adsorption system besides uranium concentration. The adsorption efficiency decreased with the increase of the L/S ratio and pH at the pH range of 2.0-3.0 for SHA and THA or 2.5-6.0 for FHA. However, no significant difference in adsorption of U(Ⅵ) was observed at the experimental temperature. All the results implied that humic substances have different characteristics in samples even collected at the same site. 展开更多
关键词 腐殖狻 土壤 天然放射物 环境放射学
下载PDF
Adsorption of Cr(VI) by modified chitosan from heavy-metal polluted water of Xiangjiang River, China 被引量:14
4
作者 刘韵琴 刘云国 +1 位作者 胡新将 郭一明 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第10期3095-3103,共9页
Methacrylic acid was used together with a molecular imprinting technique to modify chitosan. In addition, the adsorption kinetics and adsorption isotherms were recorded and the results were analyzed to investigate rep... Methacrylic acid was used together with a molecular imprinting technique to modify chitosan. In addition, the adsorption kinetics and adsorption isotherms were recorded and the results were analyzed to investigate reparative adsorption for Cr(VI) from the polluted Xiangjiang River water. A comparative X-ray analysis shows that the degree of crystallization in the imprinted polymer was significantly weakened, the area of the non-crystalline region was larger. There were more adsorption sites in the imprinted polymer, and the adsorption capacity towards Cr(VI) was increased. The adsorption capacity of the imprinted polymer towards Cr(VI) increased with time and reaches saturation after 8 h. The optimal adsorption time was 4-8 h after the adsorption starting and the optimal pH value for the solution was in the range of 4.5-7.5. When the chitosan reaches saturation, the adsorption capacity achieves a state of equilibrium, and the maximum Cr(VI) extraction rate reaches 33.7%. Moreover, the adsorption capacity of the imprinted polymer towards Cr(VI) increases with increasing chitosan concentration. In this situation, the Cr(VI) extraction rate shows little variation, and the maximum removal rate can reach 98.3%. Furthermore, the Cr(VI) extraction rate increases with an increase in the degree of deacetylation in the chatoyant and chitosan, with the best adsorption effect corresponding to 90% deacetylation. Fitting the adsorption data to the quasi first- and second-order kinetic models yields correlation coefficients of 0.9013 and 0.9875, respectively. The corresponding rate constants for the two models are 0.0091 min-1 and 7.129 g/(mg.min), respectively. Hence, the adsorption using Cr(VI)-imprinted chitosan is more consistent with the second-order kinetics. Comparing the data to Freundlich and Langrnuir adsorption isotherms shows that the latter has a better linear fit and a maximum adsorption capacity of 15.784 mg/g. 展开更多
关键词 modified chitosan IMPRINTING heavy metal pollutants Cr(vi adsorption removal rate kinetic model
下载PDF
A functionalized activated carbon adsorbent prepared from waste amidoxime resin by modifying with H_(3)PO_(4) and ZnCl_(2) and its excellent Cr(Ⅵ)adsorption 被引量:1
5
作者 Chunlin He Yun Liu +6 位作者 Mingwei Qi Zunzhang Liu Yuezhou Wei Toyohisa Fujita Guifang Wang Shaojian Ma Wenchao Yang 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第3期585-598,共14页
With the application of resins in various fields, numerous waste resins that are difficult to treat have been produced. The industrial wastewater containing Cr(Ⅵ) has severely polluted soil and groundwater environmen... With the application of resins in various fields, numerous waste resins that are difficult to treat have been produced. The industrial wastewater containing Cr(Ⅵ) has severely polluted soil and groundwater environments, thereby endangering human health. Therefore, in this paper, a novel functionalized mesoporous adsorbent PPR-Z was synthesized from waste amidoxime resin for adsorbing Cr(Ⅵ). The waste amidoxime resin was first modified with H3PO4 and ZnCl_(2), and subsequently, it was carbonized through slow thermal decomposition. The static adsorption of PPR-Z conforms to the pseudo-second-order kinetic model and Langmuir isotherm, indicating that the Cr(Ⅵ) adsorption by PPR-Z is mostly chemical adsorption and exhibits single-layer adsorption. The saturated adsorption capacity of the adsorbent for Cr(Ⅵ) could reach 255.86 mg/g. The adsorbent could effectively reduce Cr(Ⅵ) to Cr(Ⅲ) and decrease the toxicity of Cr(Ⅵ) during adsorption. PPR-Z exhibited Cr(Ⅵ) selectivity in electroplating wastewater. The main mechanisms involved in the Cr(Ⅵ) adsorption are the chemical reduction of Cr(Ⅵ) into Cr(Ⅲ) and electrostatic and coordination interactions. Preparation of PPR-Z not only solves the problem of waste resin treatment but also effectively controls Cr(Ⅵ) pollution and realizes the concept of “treating waste with waste”. 展开更多
关键词 waste amidoxime resin mesoporous adsorbent H_(3)PO_(4)and ZnCl_(2)processing Cr(vi)adsorption electroplating wastewater
下载PDF
Preparation of chitosan modified fly ash under acid condition and its adsorption mechanism for Cr(VI)in water 被引量:13
6
作者 JIANG Chun-lu WANG Rui +2 位作者 CHEN Xing ZHENG Liu-gen CHENG Hua 《Journal of Central South University》 SCIE EI CAS CSCD 2021年第6期1652-1664,共13页
Chitosan-coated fly ash(CWF)was prepared by the acid leaching-coating method.Chitosan and fly ash were crosslinked in the solution of acetic acid and sulfuric acid.The microstructure of CWF was conducted by scanning e... Chitosan-coated fly ash(CWF)was prepared by the acid leaching-coating method.Chitosan and fly ash were crosslinked in the solution of acetic acid and sulfuric acid.The microstructure of CWF was conducted by scanning electron microscope(SEM)and X-ray diffraction(XRD).The removal of Cr(VI)from water by CWF was studied by adsorption experiments.The composite prepared by the experiment developed a pore structure and a crystal structure similar to SiO_(2) and chitosan chain-like coating was formed on the surface of fly ash.The new modified material has larger surface roughness,specific surface area and more adsorption channels.The Cr(VI)was enriched in modified materials by electrostatic adsorption between CrO_(4)^(2−)、CrO_(7)^(2−)and-NH_(3)^(+) group and surface acid functional groups.The movement of Cr(VI)in solution is a diffusion process from the main body of the liquid phase to the surface of the liquid film. 展开更多
关键词 CHITOSAN fly ash(CWF) CR(vi) adsorption MODIFICATION
下载PDF
Efficient and rapid capture of uranium(Ⅵ) in wastewater via multiamine modified β-cyclodextrin porous polymer
7
作者 Xing Zhong Yubin Tan +6 位作者 Siyuan Wu Caixia Hu Kai Guo Yongchuan Wu Neng Yu Mingyang Ma Ying Dai 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2024年第4期144-155,共12页
It is quite important to ensure the safety and sustainable development of nuclear energy for the treatment of radioactive wastewater. To treat radioactive wastewater efficiently and rapidly, two multi-amine β-cyclode... It is quite important to ensure the safety and sustainable development of nuclear energy for the treatment of radioactive wastewater. To treat radioactive wastewater efficiently and rapidly, two multi-amine β-cyclodextrin polymers(diethylenetriamine β-cyclodextrin polymer(DETA-TFCDP) and triethylenetetramine β-cyclodextrin polymer(TETA-TFCDP)) were prepared and applied to capture uranium. Results exhibited that DETA-TFCDP and TETA-TFCDP displayed the advantages of high adsorption amounts(612.2and 628.2 mg·g-1, respectively) and rapid adsorption rates, which can reach(88 ± 1)% of their equilibrium adsorption amounts in 10 min. Moreover, the adsorbent processes of DETA-TFCDP and TETATFCDP on uranium(Ⅵ) followed the Langmuir model and pseudo-second-order model, stating they were mainly chemisorption and self-endothermic. Besides, TETA-TFCDP also showed excellent selectivity in the presence of seven competing cations and could be effectively reused five times via Na2CO3as the desorption reagent. Meanwhile, X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy illustrated that the enriched multi-amine groups and oxygen-containing functional groups on the surface of TETA-TFCDP were the main active sites for capturing uranium(Ⅵ). Hence, multi-amine β-cyclodextrin polymers are a highly efficient, rapid, and promising adsorbent for capturing uranium(Ⅵ)from radioactive wastewater. 展开更多
关键词 adsorption Waste water Pollution uranium(vi) b-Cyclodextrin
下载PDF
Efficient extraction of uranium(VI)from aqueous solution by Zr/Ce-UiO-66-NH_(2) modified by dual strategies of bimetallization and amination
8
作者 Wen-Hui Song Chen Wang +2 位作者 Cheng-De Xie Zhi-Xiong Zhang Jian-Jun Wang 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第11期124-137,共14页
We modified Zr/Ce-UiO-66-NH_(2) using dual bimetallization and amination strategies to efficiently extract uranium from water resources.XRD,FTIR,and XPS indicated the successful alteration of material amination.Moreov... We modified Zr/Ce-UiO-66-NH_(2) using dual bimetallization and amination strategies to efficiently extract uranium from water resources.XRD,FTIR,and XPS indicated the successful alteration of material amination.Moreover,the metal Zr was partially replaced by Ce in Zr-oxygen atom clusters in Zr/Ce-UiO-66-NH_(2).It possessed commendable structural stability in acidic and alkaline solutions.Irrespective of whether it was submerged in a 6 M strong acid or in a 0.5M strong base solution,the structural integrity of Zr/Ce-UiO-66-NH_(2) remained unaffected.Batch experiments at pH=6.0 revealed that uranium adsorption by Zr/Ce-UiO-66-NH_(2) reached 376.8 mg g^(−1) and 611.33 mg g^(−1) at 298 K and 328 K,respectively.These values are much better than those obtained using bimetallic-modified Zr/Ce-UiO-66 or amine-functionalized UiO-66-NH_(2).After five consecutive sorption and desorption cycles,the material retained a uranium removal rate of more than 80%,proving its excellent regenerative properties.Kinetic modeling of U(VI)adsorption on Zr/Ce-UiO-66-NH_(2) implied that chemisorption dominated the rapid uranium sorption rate.We propose potential adsorption mechanisms involving three interactions:inner-sphere surface complexation,chemisorption,and electrostatic interactions.This study shows that the dual strategies of bimetallization and amination can effectively enhance U(VI)extraction from water.This approach has potential applications for the structural design of uranium adsorbents. 展开更多
关键词 MOF modification Zr/Ce-UiO-66-NH_(2) adsorption uranium adsorption mechanism
下载PDF
Microwave hydrothermal synthesis,characterization and excellent uranium adsorption properties of CoFe_(2)O_(4)@rGO nanocomposite 被引量:3
9
作者 WU Shui-sheng LAN Dong-hui +4 位作者 ZHANG Xiao-wen HUANG Yi DENG Xing-hong AU Chak-tong YI Bing 《Journal of Central South University》 SCIE EI CAS CSCD 2021年第7期1955-1965,共11页
To improve the adsorption performance and simplify uranium separation from aqueous media in post-treatment processes,a magnetic CoFe_(2)O_(4)@rGO composite was synthesized by microwave-hydrothermal method.The results ... To improve the adsorption performance and simplify uranium separation from aqueous media in post-treatment processes,a magnetic CoFe_(2)O_(4)@rGO composite was synthesized by microwave-hydrothermal method.The results of XRD,Raman,TEM/HRTEM,FTIR,BET and VSM characterization show that spinel-type cobalt ferrite CoFe_(2)O_(4) nanoparticles ca.13.4 nm in size are dispersedly anchored on the graphene sheet,and the saturation magnetization of the nanocomposite is 46.7 mA/(m^(2)·g).The effects of different pH,initial concentration and other conditions on uranium adsorption capacity were investigated,and adsorption kinetics equations were fitted to determine the adsorption behaviour of uranium on CoFe_(2)O_(4)@rGO in simulated uranium-containing seawater.It was observed that the uranium adsorption capacity of CoFe_(2)O_(4)@rGO composite at pH=5 is 127.6 mg/g,which is 1.31 and 2.43 times that of rGO and pure CoFe_(2)O_(4).The adsorption process conforms to Langmuir and quasi-second-order kinetic model.The excellent adsorption performance of CoFe_(2)O_(4)@rGO makes it potentially useful in the treatment of uranium-polluted water. 展开更多
关键词 CoFe_(2)O_(4) graphene uranium adsorption properties
下载PDF
Adsorption of uranium(Ⅵ) onto amidoxime-functionalized ultrahigh molecular weight polyethylene fibers from aqueous solution 被引量:4
10
作者 Chun-Yu Xie Shi-Pei Jing +5 位作者 Yu Wang Xiao Lin Hong-Liang Bao Cheng-Zhi Guan Chan Jin Jian-Qiang Wang 《Nuclear Science and Techniques》 SCIE CAS CSCD 2017年第7期97-104,共8页
Amidoxime-functionalized ultra-high molecular weight polyethylene fibers(UHMWPEF-AO) were used to absorb uranium U(VI) from aqueous solutions.In this paper,we study effects of pH,initial U(VI) concentration,contact ti... Amidoxime-functionalized ultra-high molecular weight polyethylene fibers(UHMWPEF-AO) were used to absorb uranium U(VI) from aqueous solutions.In this paper,we study effects of pH,initial U(VI) concentration,contact time,and temperature on U(VI) adsorption by UHMWPEF-AO.The adsorption process agrees well with pseudo-second-order and Langmuir model.UHMWPEFAO exhibits excellent adsorptive performance for U(VI)with a maximum adsorption capacity of 176.12 mg/g at pH4 and 298 K.The structures of UHMWPEF-AO and U(VI)-loaded UHMWPEF-AO are characterized by FT-IR and nano-CT.U(VI)-loaded UHMWPEF-AO is sintered after adsorption process to recycle absorbed U(VI).Powders collected after sintering process are examined by scanning electron microscopy and X-ray diffraction.These results indicate that UHMWPEF-AO is a promising candidate to remove U(VI) from uranium aqueous solutions. 展开更多
关键词 超高分子量聚乙烯纤维 吸附性能 偕胺肟基 铀(Ⅵ) 水溶液 扫描电子显微镜 烧结过程 FT-IR
下载PDF
U(VI) adsorption behavior onto polypyrrole coated 3R-MoS2 nanosheets prepared with the molten salt electrolysis method 被引量:2
11
作者 Yuhui Liu Meng Tang +7 位作者 Shuang Zhang Yuling Lin Yingcai Wang Youqun Wang Ying Dai Xiaohong Cao Zhibin Zhang Yunhai Liu 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2022年第3期479-489,共11页
To improve the separation capacity of uranium in aqueous solutions, 3R-MoS2 nanosheets were prepared with molten salt electro- lysis and further modified with polypyrrole (PPy) to synthesize a hybrid nanoadsorbent (PP... To improve the separation capacity of uranium in aqueous solutions, 3R-MoS2 nanosheets were prepared with molten salt electro- lysis and further modified with polypyrrole (PPy) to synthesize a hybrid nanoadsorbent (PPy/3R-MoS2). The preparation conditions of PPy/3R- MoS2 were investigated and the obtained nanosheets were characterized with scanning electron microscope (SEM), high resolution transmis- sion electron microscope (HRTEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectro- scopy (XPS). The results showed that PPy/3R-MoS2 exhibited enhanced adsorption capacity toward U(VI) compared to pure 3R-MoS2 and PPy;the maximum adsorption was 200.4 mg/g. The adsorption mechanism was elucidated with XPS and FTIR: (1) negatively charged PPy/3R-MoS2 nanosheets attracted by an electrostatic interaction;(2) exposed C, N, Mo, and S atoms complexed with U(VI) through co- ordination;(3) Mo in the complex partly reduced the adsorbed U(VI) to U(IV), which further regenerated the adsorption point and continu- ously adsorbed U(VI). The design of the PPy/3R-MoS2 composite with a high adsorption capacity and chemical stability provides a new direc- tion for the removal of radionuclide. 展开更多
关键词 molten salt electrolysis 3R-MoS2 nanosheets polypyrrole modification adsorption uranium
下载PDF
Branched fibrous amidoxime adsorbent with ultrafast adsorption rate and high amidoxime utilization for uranium extraction from seawater 被引量:1
12
作者 Wan-Ning Ren Xin-Xin Feng +5 位作者 Yu-Long He Ming-Lei Wang Wan-Feng Hong Hong-Wei Han Jiang-Tao Hu Guo-Zhong Wu 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2023年第6期79-90,共12页
Direct collection of uranium from low uranium systems via adsorption remains challenging.Fibrous sorbent materials with amidoxime(AO)groups are promising adsorbents for uranium extraction from seawater.However,low AO ... Direct collection of uranium from low uranium systems via adsorption remains challenging.Fibrous sorbent materials with amidoxime(AO)groups are promising adsorbents for uranium extraction from seawater.However,low AO adsorption group utilization remains an issue.We herein fabricated a branched structure containing AO groups on polypropylene/polyethylene spun-laced nonwoven(PP/PE SNW)fibers using grafting polymerization induced by radiation(RIGP)to improve AO utilization.The chemical structures,thermal properties,and surface morphologies of the raw and treated PP/PE SNW fibers were studied.The results show that an adsorptive functional layer with a branching structure was successfully anchored to the fiber surface.The adsorption properties were investigated using batch adsorption experiments in simulated seawater with an initial uranium concentration of 500μg·L^(−1)(pH 4,25℃).The maximum adsorption capacity of the adsorbent material was 137.3 mg·g^(−1)within 24 h;moreover,the uranyl removal reached 96%within 240 min.The adsorbent had an AO utilization rate of 1/3.5 and was stable over a pH range of 4–10,with good selectivity and reusability,demonstrating its potential for seawater uranium extraction. 展开更多
关键词 Radiation graft technology Branching structure High amidoxime utilization Seawater uranium extraction Ultrafast adsorption
下载PDF
A study on the adsorption of chromium on laterite from Guizhou Province,China 被引量:2
13
作者 YU Xiaohong ZHU Lijun +1 位作者 GUO Baiwei HE Shouyang 《Chinese Journal Of Geochemistry》 EI CAS 2009年第2期220-226,共7页
The adsorption behaviors of Cr(VI) on laterite from Guizhou Province were studied in this paper, and the adsorption mechanism was discussed as well. Results showed that different mineral compositions in the laterite w... The adsorption behaviors of Cr(VI) on laterite from Guizhou Province were studied in this paper, and the adsorption mechanism was discussed as well. Results showed that different mineral compositions in the laterite would cause differences in the capacity of laterite to absorb Cr(VI). Gibbsite, iron oxide minerals and non-crystalloids are the main contributors to enhancing the capacity of laterite to absorb Cr(VI). The pH of the solution is an important factor affecting the adsorption of Cr(VI) on laterite. Acidic environment (pH=2-5) is favorable to the adsorption of Cr(VI). The amount of adsorbed Cr(VI) decreases with increasing pH of the solution. With increasing initial concentrations of Cr(VI), the amount of adsorbed Cr(VI) increases first, and then decreases. The optimal adsorption concentration of Cr(VI) on laterite is 250 μg/mL. The adsorption of Cr(VI) on laterite is a rapid process, about 80% Cr(VI) will be adsorbed within 2 hours. And the adsorption of Cr(VI) on kaolinite is a slow process. 展开更多
关键词 吸附行为 贵州省 红土 中国 初始浓度 氧化铁矿物 PH值
下载PDF
Potential of <i>Artocarpus heterophyllus</i>Seed Powder in the Adsorption of Chromium(VI) from Aqueous Solution
14
作者 Cranmer Lubanga Emmanuel Ntambi Christopher Adaku 《Journal of Water Resource and Protection》 2017年第6期614-628,共15页
The potential of Artocarpus heterophyllus (Jackfruit) seed powder in adsorption of chromium(VI) from aqueous solution was studied using batch technique. The performance of the adsorption process was evaluated against ... The potential of Artocarpus heterophyllus (Jackfruit) seed powder in adsorption of chromium(VI) from aqueous solution was studied using batch technique. The performance of the adsorption process was evaluated against contact time, pH, adsorbent dose, temperature and initial chromium(VI) ion concentration. The influence of the presence of interfering anionic species including chlorides, nitrates and sulphates on the adsorption process was also evaluated. The adsorption of chromium(VI) by Jackfruit seed powder reached equilibrium after 60 minutes. Higher chromium(VI) adsorption was observed at lower pH values with maximum removal (96.05%) occurring at pH 2. A great deal of adsorption (92.53%) was observed at the adsorbent dosage level of 1.0 g/100 ml solution. There was an improvement in the adsorption process when the temperature was increased from 25&#176C (95.35%) to 60&#176C (99.56%) followed by a decrease to 98.76% at 70&#176C. Adsorption decreased with increasing initial chromium(VI) ion concentration. The adsorption followed both Freundlich and Langmuir adsorption models with correlation coefficients of 0.998 and 0.994 respectively, and Qm of 0.57 mg/g. The presence of nitrate and chloride ions significantly lowered the adsorption, with all the p values 0.05. From the obtained Qm, Jackfruit Seed Powder is a good adsorbent for the aqueous solutions of Cr(VI). The adsorption process is slowed by the presence of the interfering anionic species. 展开更多
关键词 Chromium(vi) Artocarpus heterophyllus adsorption Interfering Ions
下载PDF
Application of Donnan Dialysis Coupled to Adsorption onto Activated Alumina for Chromium (VI) Removal
15
作者 I. Marzouk L. Chaabane +1 位作者 L. Dammak B. Hamrouni 《American Journal of Analytical Chemistry》 2013年第8期420-425,共6页
The aim of this paper is the assessment of Donnan dialysis coupled to adsorption process for the removal of chromium from aqueous solutions. This study was conducted in order to benefit from each process, and it was a... The aim of this paper is the assessment of Donnan dialysis coupled to adsorption process for the removal of chromium from aqueous solutions. This study was conducted in order to benefit from each process, and it was an original and new combination. The coupling was a solution to improve the contact time and the amount of chromium (VI) removed. The coupling was successfully performed with 90% of chromium (VI) removed after 6 hours. 展开更多
关键词 Donnan DIALYSIS CHROMIUM (vi) ANION-EXCHANGE Membrane adsorption ACTIVATED ALUMINA
下载PDF
Theoretical study of adsorption of water vapor on surface of metallic uranium
16
作者 XIONGBi-tao XUEWei-dong 《原子与分子物理学报》 CAS CSCD 北大核心 2002年第4期517-521,共5页
According to the experimental data, there is an intermediate substance that formed in the initial stage of oxidation reaction when water vapor is absorbed onto the metallic uranium. The minimum energy of UOH 2 wich C ... According to the experimental data, there is an intermediate substance that formed in the initial stage of oxidation reaction when water vapor is absorbed onto the metallic uranium. The minimum energy of UOH 2 wich C 2v configuration is obtained in the state of 5A 1 by B3LYP method of the density function theory (DFT), which is consistent with that by statics of atoms and molecules reaction (AMRS) and group theory. The results from calculations indicate that the adsorption of water vapor on the metallic uranium is an exothermic reaction and that the adsorbed amount decreases with the elevated temperatures. the adsorptive heat at 1 atm is -205.474 7 kJ.mol -1 , which indicates a typical chemical adsorption. 展开更多
关键词 吸收 密度泛函理论 水蒸汽 DFT
下载PDF
海藻酸钠基凝胶吸附材料对Cr(VI)吸附性能研究
17
作者 王红菊 《广州化工》 CAS 2024年第3期50-52,共3页
海藻酸钠(SA)是一种天然生物质材料,其来源广、价格低,聚乙烯亚胺是一种含有氨基(-NH_(2))的水溶性高分子聚合物,螯合重金属离子能力强,众多研究者将二者结合其制备成吸附剂去除水溶液中的金属离子。本研究以海藻酸钠为基体,加入碳酸钙... 海藻酸钠(SA)是一种天然生物质材料,其来源广、价格低,聚乙烯亚胺是一种含有氨基(-NH_(2))的水溶性高分子聚合物,螯合重金属离子能力强,众多研究者将二者结合其制备成吸附剂去除水溶液中的金属离子。本研究以海藻酸钠为基体,加入碳酸钙和聚乙烯亚胺,以戊二醛为交联剂,经冷冻干燥后形成吸附较好的海藻酸钠-聚乙烯亚胺吸附材料。采用吸附实验研究了材料对水中Cr(VI)的吸附性能,并研究初始浓度、溶液pH、吸附时间、吸附剂用量等对吸附效果的影响。实验结果表明:在Cr(VI)溶液初始浓度为15 mg/L、吸附剂用量0.4 g、吸附时间200 min,吸附温度为313 K时,Cr(VI)去除率达90%以上。 展开更多
关键词 海藻酸钠 CR(vi) 吸附 性能
下载PDF
Isothermal, kinetic, and thermodynamic studies for solid-phase extraction of uranium(VI) via hydrazine-impregnated carbonbased material as efficient adsorbent 被引量:4
18
作者 A.Morsy M.H.Taha +3 位作者 Muhammad Saeed Amir Waseem Muhammad Asad Riaz M.M.Elmaadawy 《Nuclear Science and Techniques》 SCIE CAS CSCD 2019年第11期41-51,共11页
The current study describes the application of a new extraction method for efficient uranium adsorption via cost-effective hydrazine-impregnated activated carbon.Various experimental parameters such as time, adsorbent... The current study describes the application of a new extraction method for efficient uranium adsorption via cost-effective hydrazine-impregnated activated carbon.Various experimental parameters such as time, adsorbent weight, temperature(°C), and uranium concentration were thoroughly investigated. The synthesized adsorbent was characterized via X-ray diffraction, Fourier transformation infrared spectroscopy(FT-IR), scanning electron microscopy, and thermogravimetric analysis. The results showed86% uranium extraction under optimized conditions(20% P2O5 at 25 °C, 120 min). The obtained findings fit well with thermodynamic and isothermal(Langmuir and Freundlich isotherms) models and pseudo second-order kinetics. In thermodynamic studies, the negative sign of(DG°) specified the spontaneity of process, the negative sign of(DH°) revealed endothermicity, and the positive sign of(DS°) showed high randomness after adsorption. 展开更多
关键词 uranium adsorption Phosphoric acid HYDRAZINE Carbon
下载PDF
Adsorption of U(Ⅵ) from acid solution on a low-cost sorbent:equilibrium, kinetic, and thermodynamic assessments 被引量:2
19
作者 Mohamed F.Cheira Hamed I.Mira +1 位作者 Ahmed K.Sakr Saad A.Mohamed 《Nuclear Science and Techniques》 SCIE CAS CSCD 2019年第10期105-122,共18页
In this paper,waste clay was cured with ethyl acetate to obtain treated clay(TC),which was modified with gallic acid to obtain a low-cost sorbent that was characterized by EDX,SEM,and FTIR analysis.Uranium(Ⅵ)adsorpti... In this paper,waste clay was cured with ethyl acetate to obtain treated clay(TC),which was modified with gallic acid to obtain a low-cost sorbent that was characterized by EDX,SEM,and FTIR analysis.Uranium(Ⅵ)adsorption was achieved using the batch adsorption method on the TC and gallic acid-modified treated clay(GMTC).The maximum uptakes of U(Ⅵ)on TC and GMTC were 37.2 and 193.0 mg/g,respectively.The U(Ⅵ)adsorption kinetics on the TC and GMTC sorbents were well-fitted by the pseudo-second-order mechanism,and the adsorption equilibrium followed the Langmuir model.The optimum parameters were applied to El Sela leach solution for uranium recovery. 展开更多
关键词 Waste clay Gallic acid Modification uranium adsorption EQUILIBRIUM kinetics
下载PDF
Adsorption of Cr(Ⅵ) in wastewater using magnetic multi-wall carbon nanotubes 被引量:2
20
作者 Zhuo-nan Huang Xiao-ling Wang De-suo Yang 《Water Science and Engineering》 EI CAS CSCD 2015年第3期226-232,共7页
Magnetic multi-wall carbon nanotubes were prepared with wet chemical treatments and characterized by a transmission electron microscope (TEM) and X-ray diffraction (XRD). They were used as adsorbents for the remov... Magnetic multi-wall carbon nanotubes were prepared with wet chemical treatments and characterized by a transmission electron microscope (TEM) and X-ray diffraction (XRD). They were used as adsorbents for the removal of Cr(VI) in aqueous solutions. The effects of adsorbent dosage, the concentration of Cr(VI) in aqueous solution, temperature, and pH value on the removal efficiency were studied. Results showed that the adsorption capacity of the magnetic multi-wall carbon nanotubes increased with the initial Cr(VI) concentration, but decreased with the increase of adsorbent dosage. The adsorption amount increased with contact time. The adsorption kinetics were best represented by the pseudo second-order kinetic model, and the adsorption isotherms indicated that the Langmuir model better reflected the adsorption process. The ob- tained calculation results for the Gibbs free energy revealed that the adsorption was a spontaneous and endothermic process. The enthalpy deviation was 3.835 kJ.mol 1. The magnetic multi-wall carbon nanotubes showed significant potential for application in adsorption of heavy metal ions. 展开更多
关键词 Magnetic multi-wall carbon nanotubes Cr(vi adsorption KINETICS THERMODYNAMICS
下载PDF
上一页 1 2 43 下一页 到第
使用帮助 返回顶部