共查询到20条相似文献,搜索用时 24 毫秒
1.
The coupling of sand with ZVI/oxidants achieved proportional and highly efficient removal of arsenic
Sana Ullah Xuejun Guo Xiaoyan Luo Xiangyuan Zhang Yameng Li Ziyu Liang 《Frontiers of Environmental Science & Engineering》2020,14(6):94
2.
Water-dissolved oxygen was supplied into anaerobic aquifer , which oxidized Fe(II), Mn(II) and trivalent arsenic and changed
them into undissolved solid matter through hydrolysis, precipitation, co-precipitation and adsorption processes. The experiment
was carried out on the column imitated a bore core of anaerobic aquifer with water phase containing Fe(II), Mn(II), As(III)
concentration of 45.12 mg/L, 14.52 mg/L, 219.4 μg/L, respectively and other ions similarly composition in groundwater. After
6 days of air supply, concentration of iron reduced to 0.38 mg/L, manganese to 0.4 mg/L, arsenic to 9.8 μg/L (equivalent 99.16%
of iron, 97.25% of manganese and 95.53% of arsenic fixed), and for other ions, the concentration changed almost according
to general principles. Ion phosphate and silicate strongly influenced on arsenic removal but supported iron and manganese
precipitation from water phase. Based on the experimental results, new model of groundwater exploitation was proposed. 相似文献
3.
Yuling CAI Bin LIANG Zhanqiang FANG Yingying XIE Eric Pokeung TSANG 《Frontiers of Environmental Science & Engineering》2015,9(5):879
As a promising in situ remediation technology, nanoscale zero-valent iron (nZVI) can remove polybrominated diphenyl ethers such as decabromodiphenyl ether (BDE209) effectively, However its use is limited by its high production cost. Using steel pickling waste liquor as a raw material to prepare nanoscale zero-valent metal (nZVM) can overcome this deficiency. It has been shown that humic acid and metal ions have the greatest influence on remediation. The results showed that nZVM and nZVI both can effectively remove BDE209 with little difference in their removal efficiencies, and humic acid inhibited the removal efficiency, whereas metal ions promoted it. The promoting effects followed the order Ni2+>Cu2+>Co2+ and the cumulative effect of the two factors was a combination of the promoting and inhibitory individual effects. The major difference between nZVM and nZVI lies in their crystal form, as nZVI was found to be amorphous while that of nZVM was crystal. However, it was found that both nZVM and nZVI removed BDE209 with similar removal efficiencies. The effects and cumulative effects of humic acid and metal ions on nZVM and nZVI were very similar in terms of the efficiency of the BDE209 removal. 相似文献
4.
Rong Cheng Jianlong Wang Weixian Zhang 《Frontiers of Environmental Science & Engineering》2008,2(1):103-108
Chlorophenols (CPs), as important contaminants in groundwater, are toxic and difficult to biodegrade. Recently nanoscale zero-valent iron received a great deal of attention because of its excellent performance in treating recalcitrant compounds. In this study, nanoscale zero-valent iron particles were prepared using chemical reduction, and the reductive transformations of three kinds of chlorinated phenols (2-CP, 3-CP, and 4-CP) by nanoscale zero-valent iron under different conditions were investigated. The transformation process of the CPs was shown to be dechlorination first, then cleavage of the benzene ring. The removal efficiency of the CPs varied as follows: 2-CP > 3-CP > 4-CP. The reactivity of CPs was associated with their energy of lowest unoccupied molecular orbit (E LUMO). With the increase in initial concentrations of CPs, removal efficiency decreased a little. But the quantities of CPs reduced increased evidently. Temperature had influence on not only the removal efficiency, but also the transformation pathway. At higher temperatures, dechlorination occurred prior to benzene ring cleavage. At lower temperatures, however, the oxidation product was formed more easily. 相似文献
5.
Md. Lutfor RAHMAN Shaheen M. SARKAR Mashitah Mohd YUSOFF 《Frontiers of Environmental Science & Engineering》2016,10(2):352-361
Poly(hydroxamic acid)-poly(amidoxime) chelating ligands were synthesized from poly(methyl acrylate-co-acrylonitrile) grafted acacia cellulose for removing toxic metal ions from industrial wastewaters. These ligands showed higher adsorption capacity to copper (2.80 mmol?g−1) at pH 6. In addition, sorption capacities to other metal ions such as iron, zinc, chromium, and nickel were also found high at pH 6. The metal ions sorption rate (t1/2) was very fast. The rate of adsorption of copper, iron, zinc, chromium, nickel, cobalt, cadmium and lead were 4, 5, 7, 5, 5, 8, 9 and 11 min, respectively. Therefore, these ligands have an advantage to the metal ions removal using the column technique. We have successfully investigated the known concentration of metal ions using various parameters, which is essential for designing a fixed bed column with ligands. The wastewater from electroplating plants used in this study, having chromium, zinc, nickel, copper and iron, etc. For chromium wastewater, ICP analysis showed that the Cr removal was 99.8% and other metal ions such as Cu, Ni, Fe, Zn, Cd, Pb, Co and Mn removal were 94.7%, 99.2%, 99.9%, 99.9%, 99.5%, 99.9%, 95.6% and 97.6%, respectively. In case of cyanide wastewater, the metal removal, especially Ni and Zn removal were 96.5 and 95.2% at higher initial concentration. For acid/alkali wastewater, metal ions removing for Cd, Cr and Fe were 99.2%, 99.5% and 99.9%, respectively. Overall, these ligands are useful for metal removal by column method from industrial wastewater especially plating wastewater. 相似文献
6.
Gaoling Wei Jinhua Zhang Jinqiu Luo Huajian Xue Deyin Huang Zhiyang Cheng Xinbai Jiang 《Frontiers of Environmental Science & Engineering》2019,13(4):61
7.
Chengjie Xue Juan Wu Kuang Wang Yunqiang Yi Zhanqiang Fang Wen Cheng Jianzhang Fang 《Frontiers of Environmental Science & Engineering》2021,15(5):101
8.
Chien-Li Lee Hsien-Yi Lee Kuo-Hung Tseng P. K. Andy Hong Chih-Ju G. Jou 《Environmental Chemistry Letters》2011,9(3):355-359
Organic compounds such as chlorobenzene cannot be effectively decomposed with currently available biological and chemical
treatment methods. Preliminary studies show that nano-scale zero-valent iron particles irradiated by microwave is effective
in decomposing chemically refractive organic compounds such as chlorobenzene. In this study, microwave is applied to enhance
chlorobenzene removal using micron-scale iron particles and nano-scale zero-valent iron particles suspended in the chlorobenzene
solution as the dielectric media. The results show that better chlorobenzene removal can be achieved when the chlorobenzene
solution is irradiated with 250 W microwave for 150 s than without microwave irradiation. The microwave radiation increases
iron reaction rate and surface activity, thus enhancing the chlorobenzene removal. The microwave-induced iron particles cause
the chlorobenzene activation energy to drop 34.0% for micron-scale iron and 16.1% for nano-scale zero-valent iron. They can
remove 13.6 times more chlorobenzene for micro iron, and 3.6 times more chlorobenzene for nano iron. We have demonstrated
that the microwave-induced nano-scale iron particles are effective in treating toxic organic substances as demonstrated in
this laboratory study. 相似文献
9.
Fangfang CHANG Jiuhui QU Xu ZHAO Wenjun LIU Kun WU 《Frontiers of Environmental Science & Engineering》2011,5(4):512-518
Fe-Mn binary oxide incorporated into porous diatomite (FMBO-diatomite) was prepared in situ and regenerated in a fixed-bed column for arsenite [As(III)] and arsenate [As(V)] removal. Four consecutive adsorption cycles were operated under the following conditions: Initial arsenic concentration of 0.1 mg·L-1, empty bed contact time of 5 min, and pH 7.0. About 3000, 3300, 3800, and 4500 bed volumes of eligible effluent (arsenic concentration≤0.01 mg·L-1) were obtained in four As(III) adsorption cycles; while about 2000, 2300, 2500, and 3100 bed volumes of eligible effluent were obtained in four As(V) adsorption cycles. The dissection results of FMBO-diatomite fixed-bed exhibited that small amounts of manganese and iron were transferred from the top of the fixed-bed to the bottom of the fixed-bed during As(III) removal process. Compared to the extremely low concentration of iron (<0.01 mg·L-1), the fluctuation concentration of Mn2+ in effluent of the As(III) removal column was in a range of 0.01–0.08 mg·L-1. The release of manganese suggested that manganese oxides played an important role in As(III) oxidation. Determined with the US EPA toxicity characteristic leaching procedure (TCLP), the leaching risk of As(III) on exhausted FMBO-diatomite was lower than that of As(V). 相似文献
10.
One-step synthesis of bentonite-supported nanoscale Fe/Ni bimetals for rapid degradation of methyl orange in water 总被引:1,自引:0,他引:1
Although nanoscale zero-valent iron (nano-Fe0) is used to remediate pollutants, this reagent still presents stability and reactivity issues. To solve those issues, we synthesized bentonite-supported nanoscale iron bimetals B-Fe/Ni and B-Fe/Pd. We then used those reagents to degrade the methyl orange dye in water. Results of scanning electron microscopy and X-ray diffraction showed that the presence of bentonite and bimetal decreased nanoscale iron aggregation and increased methyl orange removal efficiency. More than 90 % of methyl orange at 100 mg/L was degraded by B-Fe/Ni (0.15 g/L) in 10 min. By comparison, only 62 % of methyl orange was degraded by B-Fe, and 35 % of methyl orange was degraded by nano-Fe0. The degradation rate decreased with the increase of the initial concentration of methyl orange. Lower pH allowed fast removal of methyl orange. Overall our findings show that a nanoscale Fe/Ni on bentonite-supported material is more efficient than nano-Fe0. One-step synthesis is more convenient than current two-step-synthesized nanoscale bimetals. Bentonite-supported nanoscale bimetals could therefore be an economic competitive candidate for contaminated water remediation. 相似文献
11.
Izabela Polowczyk Anna Bastrzyk Tomasz Koźlecki Wojciech Sawiński Piotr Rudnicki Adam Sokołowski Zygmunt Sadowski 《Environmental geochemistry and health》2010,32(4):361-366
The aim of this work is to investigate the application of fly ash adsorbent for removal of arsenite ions from dilute solution
(100–1,000 ppm). Experiments were carried out using material from the “Turów” (Poland) brown-coal-burning power plant, which
was wetted, then mixed and tumbled in a granulator to form spherical agglomerates. Measurements of arsenic adsorption from
aqueous solution were carried out at room temperature and natural pH of fly ash agglomerates, in either a shaken flask or
circulating column, to compare two different methods of contacting solution with adsorbent. Adsorption isotherms of arsenic
were determined for agglomerated material using the Freundlich equation. Kinetic studies indicated that sorption follows a
pseudo-second-order model. Preferable method to carry out the process is continuous circulation of arsenite solution through
a column. 相似文献
12.
Robert D. ARTHUR Jagadish TORLAPATI Kyung-Hee SHIN Daniel K. CHA Yeomin YOON Ahjeong SON 《Frontiers of Environmental Science & Engineering》2014,8(3):386-393
Process control parameters influencing microbial perchlorate reduction via a flow-through zero-valent iron (ZVI) column reactor were investigated in order to optimize perchlorate removal from water. Mixed perchlorate reducers were obtained from a wastewater treatment plant and inoculated into the reactor without further acclimation. Examined parameters included hydraulic residence time (HRT), pH, nutrients requirement, and perchlorate reduction kinetics. The minimum HRT for the system was concluded to be 8 hr. The removal efficiency of 10 mg. L-1 influent perchlorate concentration was reduced by 20%-80% without control to the neutral pH (HRT = 8 hr). Therefore pH was determined to be an important parameter for microbial perchlorate reduction. Furthermore, a viable alternative to pH buffer was discussed. The microbial perchlorate reduction followed the first order kinetics, with a rate constant (K) of 0.761 hr-1. The results from this study will contribute to the implementation of a safe, cost effective, and efficient system for perchlorate reduction to below regulated levels. 相似文献
13.
壳聚糖稳定纳米铁去除地表水中Cr(Ⅵ)污染的影响因素 总被引:1,自引:0,他引:1
以壳聚糖为稳定剂,制备纳米零价铁颗粒,TEM表征结果显示:其粒径分布范围为20—150 nm,平均粒径为82.4 nm.研究表明,壳聚糖稳定的纳米铁去除Cr(Ⅵ)的还原反应符合一级反应动力学方程.溶液中投加稳定剂壳聚糖,当壳聚糖浓度为150 mg.l-1时,80 min内表观一级动力学常数kobs约为空白溶液的2倍;干扰离子Ca2+,Mg2+,HCO3-和CO32-对壳聚糖稳定纳米铁去除Cr(Ⅵ)的批试验结果显示,Ca2+和Mg2+在80 min内使壳聚糖稳定纳米铁对Cr(Ⅵ)去除率分别降低了约20%和10%;HCO3-和CO32-的存在使去除率降低了约10%. 相似文献
14.
腐殖酸对As(V)在覆铁砂介质中吸附行为的影响 总被引:2,自引:0,他引:2
对腐殖酸(HA)进行了成分分析及红外表征,并从HA浓度、pH值、As(Ⅴ)初始浓度等方面,研究了HA对As(Ⅴ)在覆铁砂介质中吸附行为的影响.结果表明,随着HA浓度的升高,总砷去除率逐渐降低.当HA浓度增加到25mg.l-1时,与不存在HA条件下相比,总砷去除率降低了12%左右.溶液pH值影响As(Ⅴ)的去除,pH值从6升高到8时,总砷去除率从52.1%降到了39%.其中的作用机理主要是HA与As(Ⅴ)在覆铁砂表面形成竞争吸附,HA争夺了As(Ⅴ)的吸附点位.此外,HA与Fe(Ⅲ)的络合作用也是导致覆铁砂对砷的去除率降低的一个重要原因. 相似文献
15.
零价铁还原和过硫酸盐氧化联合降解水中硝基苯 总被引:3,自引:0,他引:3
将零价铁(Fe0)的还原和过硫酸盐(persulfate,PS)的高级氧化技术结合用于水中难降解有机污染物硝基苯的去除.研究结果表明,Fe0在常温常压下可将硝基苯还原生成苯胺,随着Fe0投加量的增加,硝基苯还原为苯胺的速率逐渐增大.PS本身对硝基苯氧化作用不明显,但在Fe0与PS二者联合体系中,硝基苯和苯胺同时被去除,而且随着PS投加量的增加二者被去除的速度也随之增加.在Fe0还原和PS氧化联合处理硝基苯的体系中可能存在两个过程,一是Fe0还原硝基苯产生苯胺和二价铁离子Fe2+,二是Fe2+催化PS产生强氧化性的硫酸根自由基将苯胺氧化降解. 相似文献
16.
E. L. Ander M. J. Watts P. L. Smedley E. M. Hamilton R. Close H. Crabbe T. Fletcher A. Rimell M. Studden G. Leonardi 《Environmental geochemistry and health》2016,38(6):1313-1332
Tap water from 497 properties using private water supplies, in an area of metalliferous and arsenic mineralisation (Cornwall, UK), was measured to assess the extent of compliance with chemical drinking water quality standards, and how this is influenced by householder water treatment decisions. The proportion of analyses exceeding water quality standards were high, with 65 % of tap water samples exceeding one or more chemical standards. The highest exceedances for health-based standards were nitrate (11 %) and arsenic (5 %). Arsenic had a maximum observed concentration of 440 µg/L. Exceedances were also high for pH (47 %), manganese (12 %) and aluminium (7 %), for which standards are set primarily on aesthetic grounds. However, the highest observed concentrations of manganese and aluminium also exceeded relevant health-based guidelines. Significant reductions in concentrations of aluminium, cadmium, copper, lead and/or nickel were found in tap waters where households were successfully treating low-pH groundwaters, and similar adventitious results were found for arsenic and nickel where treatment was installed for iron and/or manganese removal, and successful treatment specifically to decrease tap water arsenic concentrations was observed at two properties where it was installed. However, 31 % of samples where pH treatment was reported had pH < 6.5 (the minimum value in the drinking water regulations), suggesting widespread problems with system maintenance. Other examples of ineffectual treatment are seen in failed responses post-treatment, including for nitrate. This demonstrates that even where the tap waters are considered to be treated, they may still fail one or more drinking water quality standards. We find that the degree of drinking water standard exceedances warrant further work to understand environmental controls and the location of high concentrations. We also found that residents were more willing to accept drinking water with high metal (iron and manganese) concentrations than international guidelines assume. These findings point to the need for regulators to reinforce the guidance on drinking water quality standards to private water supply users, and the benefits to long-term health of complying with these, even in areas where treated mains water is widely available. 相似文献
17.
Choi Ki Young Kim Suk Hyun Hong Gi Hoon Chon Hyo Taek 《Environmental geochemistry and health》2011,33(1):71-80
Mechanisms of natural attenuation of arsenic (As) by wetland plants may be classified by plant uptake and adsorption and/or co-precipitation by iron (oxy)hydroxide formed on the root surface of plants or in rhizosediment. A natural Cattail (Typha spp.) wetland impacted by tailings containing high levels of As from the Myungbong abandoned Au Mine, South Korea was selected, and the practical capability of this wetland to attenuate As was evaluated. The As concentrations in the plant tissues from the study wetland were several-fold higher than those from control wetland. SEM-EDX analyses demonstrated that iron plaques exist on the rhizome surface. Moreover, relatively high As contents bonded with hydrous iron oxides were found in the rhizosediments rather than in the bulk sediments. It was revealed through the leaching and sequential extraction analyses that As existed as more stable forms in the wetland sediment compared with adjacent paddy soil, which is also contaminated with As due to input of mine tailings. The As concentration ratios of extracted solution to sediment/soil represented that the wetland sediment showed significant lower values (10-fold) rather than the paddy soil with indicating high As stability. Also, As in the wetland sediment was predominantly bonded with residual phases on the basis of results from sequential extraction analysis. From these results, it is concluded that transformation of As contaminated agricultural field to wetland environment may be helpful for natural attenuation until active remediation action. 相似文献
18.
Akbar Soliemanzadeh Majid Fekri Somayeh Bakhtiary Majid Hejazi Mehrizi 《Chemistry and Ecology》2016,32(3):286-300
This paper reports the biosynthesis of nanoscale zero-valent iron (nZVI) using the extracts of Shirazi thyme leaf (Th-nZVI) and pistachio green hulls (P-nZVI). Scanning electron microscopy verified the successful synthesis of the poorly crystalline nZVI with a spherical shape and diameter in the range of 40–70 nm. According to X-ray diffraction and Fourier transform infrared spectroscope analyses, the synthesised nZVI were composed of iron oxides nanoparticles and ployphenol obtained from Shirazi thyme leaf and pistachio green hulls extracts acting as both reducing and capping agents. The phosphorus removal efficiency of Th-nZVI and P-nZVI increased with time and reached equilibrium at about 4 and 2h, respectively. Sorption of phosphorus on both sorbents was observed to be pH-dependent with maximum phosphorus removal occurring in the pH range of 2–5. Langmuir, Freundlich, Redlich–Peterson, and Temkin models were used to describe phosphorus sorption at pH 5 and maximum sorption capacity for Th-nZVI and P-nZVI was about 40.52 and 29.33?mg?g?1, respectively. Correlation coefficient (R2) and standard errors of estimate showed that the Elovich model was better than other models at describing the kinetic data. These results suggested that the synthesised nZVI with Shirazi thyme leaf and pistachio green hulls extracts could be employed as an efficient sorbent for the remediation of phosphorus from contaminated water sources. 相似文献
19.
Hu Y Li JH Zhu YG Huang YZ Hu HQ Christie P 《Environmental geochemistry and health》2005,27(2):169-176
A pot experiment was carried out in a greenhouse to investigate the sequestration of As in iron plaques on root surface of
three rice (Oryza sativa L.) cultivars. Phosphate (P) fertilization increased both plant biomass and tissue P concentrations significantly, indicating
that the soils used in this study was highly P-deficient. Results from this study confirmed that low P supply improved the
formation of iron plaque on rice roots. As a consequence, arsenic (As) concentrations in DCB-extracts with no P addition were
significantly higher than those with P fertilization. Arsenic was highly sequestrated in iron plaque; arsenic concentration
in iron was up to nearly 120 mg kg−1, while arsenic concentrations in roots were just several mg kg−1. Both arsenic and phosphate concentrations in iron plaque were highly positively correlated with the amounts of iron plaque
(DCB-extractable Fe). Contrary to normal understanding that increasing P supply could reduced As accumulation in plants, results
from the present study showed that P fertilization did not inhibit the As uptake by plants (As accumulation in aboveground),
which was probably due to the fact that iron plaque formation was improved under low P conditions, thus leading to more As
sequestration in the iron plaque. Thus results obtained in this study indicated that the iron plaque may inhibit the transfer
of As from roots to shoots, and thus alter the P–As interaction in plant As uptake processes. 相似文献
20.
Mechanisms of natural attenuation of arsenic (As) by wetland plants may be classified by plant uptake and adsorption and/or co-precipitation by iron (oxy)hydroxide formed on the root surface of plants or in rhizosediment. A natural Cattail (Typha spp.) wetland impacted by tailings containing high levels of As from the Myungbong abandoned Au Mine, South Korea was selected, and the practical capability of this wetland to attenuate As was evaluated. The As concentrations in the plant tissues from the study wetland were several-fold higher than those from control wetland. SEM-EDX analyses demonstrated that iron plaques exist on the rhizome surface. Moreover, relatively high As contents bonded with hydrous iron oxides were found in the rhizosediments rather than in the bulk sediments. It was revealed through the leaching and sequential extraction analyses that As existed as more stable forms in the wetland sediment compared with adjacent paddy soil, which is also contaminated with As due to input of mine tailings. The As concentration ratios of extracted solution to sediment/soil represented that the wetland sediment showed significant lower values (10-fold) rather than the paddy soil with indicating high As stability. Also, As in the wetland sediment was predominantly bonded with residual phases on the basis of results from sequential extraction analysis. From these results, it is concluded that transformation of As contaminated agricultural field to wetland environment may be helpful for natural attenuation until active remediation action. 相似文献