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1.
Comparing the adsorption behaviors of Cd,Cu and Pb from water onto Fe-Mn binary oxide,MnO2 and FeOOH
Wei XU Huachun LAN Hongjie WANG Hongming LIU Jiuhui QU 《Frontiers of Environmental Science & Engineering》2015,9(3):385
The adsorption potential of FMBO, FeOOH, MnO2 for the removal of Cd2+, Cu2+ and Pb2+ in aqueous systems was investigated in this study. Comparing to FMBO and FeOOH, MnO2 offered a much higher removal capacity towards the three metal ions. The maximal adsorption capacity of MnO2 for Cd2+, Cu2+ and Pb2+ were 1.23, 2.25 and 2.60 mmol·g-1, respectively. And that for FMBO were 0.37, 1.13, and 1.18 mmol·g-1 and for FeOOH were 0.11, 0.86 and 0.48 mmol·g-1, respectively. The adsorption behaviors of the three metal ions on the three adsorbents were all significantly affected by pH values and heavy metal removal efficiency increased with pH increased. The Langmuir and Freundlich adsorption models were used to describe the adsorption equilibrium of the three metal ions onto the three adsorbents. Results showed that the adsorption equilibrium data fitted well to Langmuir isotherm and this indicated that adsorption of metal ions occurred on the three metal oxides adsorbents limited to the formation of a monolayer. More negative charged of MnO2 surface than that of FMBO and FeOOH could be ascribed by lower pHiep of MnO2 than that of FMBO and FeOOH and this could contribute to more binding sites on MnO2 surface than that of FMBO and FeOOH. The higher metal ions uptake by MnO2 than FMBO and FeOOH could be well explained by the surface charge mechanism. 相似文献
2.
Wei WANG Yan MA Qing ZHOU Chendong SHUANG Mancheng ZHANG Aimin LI 《Frontiers of Environmental Science & Engineering》2015,9(1):96
A rapid and effective method based on a novel permanent magnetic hypercrosslinked resin W150 was proposed for the removal of organic micropollutants in drinking water. W150 was prepared by suspension and post-crosslinking reaction and found to possess a high specific surface area of 1149.7 m2·g-1, a small particle size of 50 μm to 100 μm, and a saturation magnetization as high as 8 emu·g-1. W150 was used to eliminate nitrofurazone (NFZ) and oxytetracycline (OTC) from drinking water compared with commercial adsorbents XAD-4 and F400D. The adsorption kinetics of NFZ and OTC onto the three adsorbents well fitted the pseudo-second-order equation (r>0.972), and the adsorption isotherms were all well described by the Freundlich equation (r>0.851). Results showed that the reduction in adsorbent size and the enlargement in sorbent pores both accelerated adsorption. Moreover, the effect of particle size on adsorption was more significant than that of pore width. Given that the smallest particle size and the highest specific surface area were possessed by W150, it had the fastest adsorption kinetics and largest adsorption capacity for NFZ (180 mg·g-1) and OTC (200 mg·g-1). For the adsorbents with dominant micropores, the sorption of large-sized adsorbates decreased because of the inaccessible micropores. The solution pH and ionic strength also influenced adsorption. 相似文献
3.
Junlian QIAO Zimin CUI Yuankui SUN Qinghai HU Xiaohong GUAN 《Frontiers of Environmental Science & Engineering》2014,8(2):169-179
A1-Fe (hydr)oxides with different A1/Fe molar ratios (4:1, 1:1, 1:4, 0:1) were prepared using a co- precipitation method and were then employed for simultaneous removal of arsenate and fluoride. The 4A1 : Fe was superior to other adsorbents for removal of arsenate and fluoride in the pH range of 5.0-9.0. The adsorption capacity of the A1-Fe (hydr)oxides for arsenate and fluoride at pH 6.50.3 increased with increasing A1 content in the adsorbents. The linear relationship between the amount of OH released from the adsorbent and the amount of arsenate or fluoride adsorbent by 4A1 : Fe indicated that the adsorption of arsenate and fluoride by A1- Fe (hydr)oxides was realized primarily through quantita- tive ligand exchange. Moreover, there was a very good correlation between the surface hydroxyl group densities of A1-Fe (hydr)oxides and their adsorption capacities for arsenate or fluoride. The highest adsorption capacity for arsenate and fluoride by 4A1 : Fe is mainly ascribed to its highest surface hydroxyl group density besides its largest pHpzc. The dosage of adsorbent necessary to remove arsenate and fluoride to meet the drinking water standard was mainly determined by the presence of fluoride since fluoride was generally present in groundwater at much higher concentration than arsenate. 相似文献
4.
Qing ZHOU Mengqiao WANG Aimin LI Chendong SHUANG Mancheng ZHANG Xiaohan LIU Liuyan WU 《Frontiers of Environmental Science & Engineering》2013,7(3):412-419
A novel hyper-crosslinked resin (MENQ) modified with an anion exchange group was prepared using divinylbenzene (DVB) and methyl acrylate (MA) as comonomers via four steps: suspension polymerization, post-crosslinking, ammonolysis and alkylation reactions. The obtained resin had both a high specific surface area (793.34 m2·g-1) and a large exchange capacity (strong base anion exchange capacity, SEC: 0.74 mmol·g-1, weak base anion exchange capacity, WEC: 0.45 mmol·g-1). XAD-4 was selected as an adsorbent for comparison to investigate the adsorption behavior of tetracycline (TC) and humic acid (HA) onto the adsorbents. The results revealed that MENQ could effectively remove both TC and HA. The adsorption capacity of XAD-4 for TC was similar to that of MENQ, but XAD-4 exhibited poor performance for the adsorption of HA. The adsorption isotherms of TC and HA were well-fitted with the Freundlich model, which indicated the existence of heterogeneous adsorption through cation-π bonding and π–π interactions. The optimal solution condition for the adsorption of TC was at a pH of 5–6, whereas the adsorption of HA was enhanced with increasing pH of the solution. 相似文献
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This work explores the feasibility of Jerusalem artichoke stem (JAS), an agricultural waste, as an alternative precursor for fabrication of mesoporous activated carbon (MAC) via conventional ZnCl2 activation. The as-prepared JAS-MACs were characterized by thermogravimetric, nitrogen gas adsorption isotherm and high resolution scanning electron microscopy analysis. The interacting effects of chemical dosage, activation temperature and time on the mesoporosity, mesopore volume and carbon yield were investigated, and further optimized by response surface methodology (RSM). The Brunauer-Emmett-Teller surface area, mesoporosity and mesopore volume of the JAS-MAC prepared under optimum condition were identified to be 1631 m2·g-1, 90.16% and 1.11 cm3·g-1, respectively. Compared with commercial activated carbons, this carbon exhibited a comparable monolayer adsorption capacity of 374.5 mg·g-1 for Methylene Blue dye. The findings suggest that RSM could be an effective approach for optimizing the pore structure of fabricated activated carbons. 相似文献
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The chromium(VI) biosorption onto guava seeds, as an alternative method for Cr6+ removal from aqueous solutions, was investigated. The parameters affecting kinetics and equilibrium of Cr6+ adsorption onto guava seeds were studied. An external mass-transfer diffusion coefficient k and intra-particle diffusion coefficient ki were determined to measure the rate-limiting step of adsorption. A single external mass-transfer diffusion model and intra-particle diffusion models were used. The effects of initial pH, sorbent mass, and initial Cr6+ concentrations on mass-transfer coefficients were investigated. The external mass-transfer coefficient has an average value of 7.2×10-3 cm s-1, while the intra-particle mass-transfer diffusion coefficient was 0.34 mg g-1 min-0.5. This indicates that external diffusion to the guava seeds surface and intra-particle diffusion are both involved in the sorption process. The isotherm equilibrium data were well fitted by the Langmuir and Freundlich models with an average correlation coefficient R2=0.98. The maximum removal of Cr6+ was obtained at pH 1 (about 100% for adsorbent dose of 15 g l-1 and 25 mg l-1 initial concentration of Cr6+). The results indicated that the guava seeds exhibit acceptable sorption capacity. 相似文献
7.
以天然高分子化合物海藻酸钠(sodium alginate,SA)为骨架,结合磁性Fe3O4和稀土铈离子Ce(Ⅲ)通过溶液反应制备出一种新型的磁性海藻酸铈复合微球(Fe3O4@SA;Ce).采用X射线衍射(XRD)、孔结构比表面积分析(BET)、扫描电子显微镜(SEM)、红外光谱(FT-IR)及振动样品强磁计(VSM)对Fe3O4@SA;Ce的结构进行了表征,并以直接桃红12B(direct red 12B,DR 12B)和直接橙S(direct orange S,DO S)两种染料为吸附对象,探讨了Fe3O4@SA;Ce的吸附剂性能、吸附动力学和热力学.结果表明,Fe3O4@SA;Ce对室温下自然pH染料溶液中DR 12B和DO S均表现出良好的吸附效果,吸附量分别可达464 mg·g-1和730 mg·g-1.在不同温度下(298、313、328 K),Fe3O4@SA;Ce对DR 12B和DO S的吸附过程均可用拟二级吸附动力学方程准确描述.通过等温吸附研究,发现Fe3O4@SA;Ce对两种染料的等温吸附较好地符合Freundlich模型.各种表征结果表明,SA与Ce(Ⅲ)和Fe3O4交联反应后生成的Fe3O4@SA;Ce凝胶球表面有大量深浅不一的褶皱沟纹,形貌发生了显著变化.作为一种绿色环保、制备方法简单、可高效吸附的磁性高分子复合吸附剂,Fe3O4@SA;Ce对高浓度染料具有很好的吸附效果,期望能够在染料废水处理中得到广泛应用. 相似文献
8.
Lijing DONG Zhiliang ZHU Yanling QIU Jianfu ZHAO 《Frontiers of Environmental Science & Engineering》2016,10(1):28-36
A novel composite adsorbent, hydroxyapatite/manganese dioxide (HAp/MnO2), has been developed for the purpose of removing lead ions from aqueous solutions. The combination of HAp with MnO2 is meant to increase its adsorption capacity. Various factors that may affect the adsorption efficiency, including solution pH, coexistent substances such as humic acid and competing cations (Ca2+, Mg2+), initial solute concentration, and the duration of the reaction, have been investigated. Using this composite adsorbent, solution pH and coexistent calcium or magnesium cations were found to have no significant influence on the removal of lead ions under the experimental conditions. The adsorption equilibrium was described well by the Langmuir isotherm model, and the calculated maximum adsorption capacity was 769 mg·g−1. The sorption processes obeyed the pseudo-second-order kinetics model. The experimental results indicate that HAp/MnO2 composite may be an effective adsorbent for the removal of lead ions from aqueous solutions. 相似文献
9.
钾改性蒙脱石磁性微球对铯的吸附性能 总被引:1,自引:0,他引:1
本研究以钙基蒙脱石(Ca-MMT)为原料,通过K+作用制得改性蒙脱石粉(K-MMT),经海藻酸钠交联作用,将改性蒙脱石与永磁体(BaFe12O19)结合,制成钾改性蒙脱石磁性微球(KMBC).对比了Ca-MMT、K-MMT、KMBC对Cs+的吸附差异,并通过SEM-EDS、FTIR、XRD、XPS分析了K-MMT的微观结构及理化性质.试验结果表明,K+对蒙脱石的改性以离子交换为主,改性后晶体层间距变小,吸附量K-MMT>KMBC>Ca-MMT,分别为57.08、45.13、45.05 mg·g-1;K-MMT对Cs+的吸附属于吸热反应,反应在2 h内可达到平衡,35℃时KMBC的最大吸附量为136.08 mg·g-1;随着pH的增加,KMBC对Cs+的吸附量呈先增大后减小的趋势;吸附机理主要包括离子交换和内层扩散. 相似文献
10.
Ning Wang Jiangtao Feng Wei Yan Luohong Zhang Yonghong Liu Ruihua Mu 《Frontiers of Environmental Science & Engineering》2022,16(8):105
11.
S. S. Baral S. N. Das P. Rath G. Roy Chaudhury Y. V. Swamy 《Chemistry and Ecology》2007,23(2):105-117
Biosorption studies of Cr(VI) were carried out using waste weed, Salvinia cucullata. Various adsorption parameters were studied, such as agitation speed, contact time, pH, particle size, and concentrations of adsorbent and adsorbate. The equilibrium was achieved in 12 h. A lower pH favoured adsorption of Cr(VI). The kinetics followed pseudo-second-order rate equations. The adsorption isotherm obeyed both the Langmuir and Freundlich models. The calculated activation energy (1.1 kJ mol-1) suggested that the adsorption followed a diffusion-controlled mechanism. Various thermodynamic parameters such as Δ G°, Δ H°, and Δ S° were also calculated. The positive values of enthalpy indicated the endothermic nature of the reaction, and Δ S° showed the increasing randomness at the solid liquid interface of Cr(VI) on the adsorbent, which revealed the ease of adsorption reaction. These thermo-dynamic parameters showed the spontaneity of the reaction. The maximum adsorption of uptake (232 mg g-1) compared well with reported values of similar adsorbents. The rate-determining step was observed to follow an intra-particle diffusion model. 相似文献
12.
Yanhui ZHAN Jianwei LIN Yanling QIU Naiyun GAO Zhiliang ZHU 《Frontiers of Environmental Science & Engineering》2011,5(1):65-75
Surfactant-modified natural zeolites (SMNZ) with different coverage types were prepared by loading hexadecyltrimethyl ammonium bromide (HTAB) onto the surface of a natural zeolite. The adsorption behavior of humic acid (HA) on SMNZ was investigated. Results indicate that the adsorbent SMNZ exhibited a higher affinity toward HA than the natural zeolite. HA removal efficiency by SMNZ increased with HTAB loading. Coexisting Ca2+ in solution favored HA adsorption onto SMNZ. Adsorption capacity decreased with an increasing solution pH. For typical SMNZ with bilayer HTAB coverage, HA adsorption process is well described by a pseudo-second-order kinetic model. The experimental isotherm data fitted well with the Langmuir model. Calculated maximum HA adsorption capacities for SMNZ with bilayer HTAB coverage at pH 5.5 and 7.5 were 63 and 41 mg·g-1, respectively. E2/E3 (absorbance at 250 nm to that at 365 nm) and E4/E6 (absorbance at 465 nm to that at 665 nm) ratios of the residual HA in solution were lower than that of the original HA solution. This indicates that the HA fractions with high polar functional groups, low molecular weight (MW), and aromaticity had a stronger tendency for adsorption onto SMNZ with bilayer HTAB coverage. Results show that HTAB-modified natural zeolite is a promising adsorbent for removal of HA from aqueous solution. 相似文献
13.
Yin WANG Xuejiang WANG Xin WANG Mian LIU Siqing XIA Daqiang YIN Yalei ZHANG Jianfu ZHAO 《Frontiers of Environmental Science & Engineering》2012,6(6):761-769
The reduction of hexavalent chromium by scrap iron was investigated in continuous long-term fixed bed system. The effects of pH, empty bed contact time (EBCT), and initial Cr(VI) concentration on Cr(VI) reduction were studied. The results showed that the pH, EBCT, and initial Cr(VI) concentration significantly affected the reduction capacity of scrap iron. The reduction capacity of scrap iron were 4.56, 1.51, and 0.57 mg Cr(VI)·g-1 Fe0 at pH 3, 5, and 7 (initial Cr(VI) concentration 4 mg·L-1, EBCT 2 min, and temperature 25°C), 0.51, 1.51, and 2.85 mg Cr(VI)·g-1 Fe0 at EBCTs of 0.5, 2.0, and 6.0 min (initial Cr(VI) concentration 4 mg·L-1, pH 5, and temperature 25°C), and 2.99, 1.51, and 1.01 mg Cr(VI)·g-1 Fe0 at influent concentrations of 1, 4, and 8 mg·L-1 (EBCT 2 min, pH 5, and temperature 25°C), respectively. Fe(total) concentration in the column effluent continuously decreased in time, due to a decrease in time of the iron corrosion rate. The fixed bed reactor can be readily used for the treatment of drinking water containing low amounts of Cr(VI) ions, although the hardness and humic acid in water may shorten the lifetime of the reactor, the reduction capacity of scrap iron still achieved 1.98 mg Cr6+·g-1 Fe. Scanning electron microscope equipped with energy dispersion spectrometer and X-ray diffraction were conducted to examine the surface species of the scrap iron before and after its use. In addition to iron oxides and hydroxide species, iron-chromium complex was also observed on the reacted scrap iron. 相似文献
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15.
Chengyuan SU Weiguang LI Yong WANG 《Frontiers of Environmental Science & Engineering》2013,7(4):503-511
The adsorption of direct fast black onto acid-thermal modified sepiolite was investigated. Batch adsorption experiments were performed to evaluate the influences of experimental parameters such as initial dye concentration, initial solution pH and adsorbent dosage on the adsorption process. The three-factor and three-level Box-Behnken response surface methodology (RSM) was utilized for modeling and optimization of the adsorption conditions for direct fast black onto the acid-thermal modified sepiolite. The raw sepiolite was converted to acid-thermal modified sepiolite, and changes in the fourier transform infrared spectrum (FTIR) adsorption bands of the sample were noted at 3435 cm-1 and 1427 cm-1. The zeolitic water disappeared and the purity of sepiolite was improved by acid-thermal modification. The decolorization rate of direct fast black adsorbed increased from 68.2% to 98.9% on acid-thermal modified sepiolite as the initial solution pH decreased from 10 to 2. When the adsorbent dosage reached to 2.5 g·L-1, 2.0 g·L-1, 1.5 g·L-1 and 1.0 g·L-1, the decolorization rate was 90.3%, 86.7%, 61.0% and 29.8%, respectively. When initial dye concentration increased from 25 to 200 mg·L-1, the decolorization rate decreased from 91.9% to 60.0%. The RSM results showed that the interaction between adsorbent dosage and pH to be a significant factor. The optimum conditions were as follows: the adsorbent dosage 1.99 g·L-1, pH 4.22, and reaction time 5.2 h. Under these conditions, the decolorization rate was 95.1%. The three dimensional fluorescence spectra of direct fast black before and after treatment showed that the direct fast black was almost all adsorbed by the acid-thermal modified sepiolite. 相似文献
16.
Jing REN Nan LI Lin ZHAO Nanqi REN 《Frontiers of Environmental Science & Engineering》2014,8(4):531-538
Ferric oxyhydroxide loaded anion exchanger (FOAE) hybrid adsorbent was prepared by loading nanosized ferric oxyhydroxide (FO) on anion exchanger resin for the removal of phosphate from wastewater. TEM and XRD analysis confirmed the existence of FO on FOAE. After FO loading, the adsorption capacity of the hybrid adsorbent increased from 38.70 to 51.52mg.g-1. Adsorption processes for both FOAE and anion resin were better fit to the pseudo first order model. Batch adsorption experiments revealed that higher temperature (313K), higher initial phosphate concentration (50 mg.L-1) and lower solution pH (pH value of 2) would be more propitious to phosphate adsorption. Competition effect of coexisting anions on phosphate removal can be concluded as sulfate 〉 nitrate 〉 chloride. Freundlich isotherm model can describe the adsorption of phosphate on FOAE more accurately, which indicated the heterogeneous adsorption occurred on the inner-surface of FOAE. 相似文献
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Qingqing Li Chao Lv Xiangwei Xia Chao Peng Yan Yang Feng Guo Jianfeng Zhang 《Frontiers of Environmental Science & Engineering》2022,16(11):138
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Igor W. K. Ouédraogo Erol Pehlivan Hien T. Tran Samuel Paré Yvonne L. Bonzi-Coulibaly Dieter Zachmann 《毒物与环境化学》2016,98(7):736-747
Arsenic (V) adsorption on manganese oxide coated rice wastes was investigated in this study. The modified adsorbents were characterized by Fourier-transform infrared spectroscopy, scanning electron microscopy, and pH measurements to determine the point of zero charge. Batch adsorption equilibrium experiments were conducted to study the effects of pH, contact time, and initial concentration on arsenic removal efficiency. The adsorption capacity of rice waste was significantly improved after modification with permanganate. The Langmuir isotherm model fitted the equilibrium data better than the Freundlich model which confirms surface homogeneity of the adsorbent. Maxima adsorption capacities are determined as 10 and 12 mg/g at pH 3 for manganese oxide coated rice husk and straw, respectively. The adsorption energy indicates that the adsorption process may be dominated by chemisorption. Pseudo-second-order rate equation described the kinetics sorption of arsenic with good correlation coefficients, better than a pseudo-first-order equation. Manganese oxide coated rice husk and straw appear to be promising low cost adsorbents for removing arsenic from water. 相似文献
20.
Ragini Pirarath Palani Shivashanmugam Asad Syed Abdallah M. Elgorban Sambandam Anandan Muthupandian Ashokkumar 《Frontiers of Environmental Science & Engineering》2021,15(1):15