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1.
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
2.
We studied the adsorption and desorption of two pesticides, namely isoproturon and dimetomorph, onto a model soil sample.
We first show that the adsorption of isoproturon depends on pH, from 1 mg g−1 at pH 4 to 2 mg g−1 at pH 10, contrary to the adsorption of dimetomorph (5.8 mg g−1). We also studied the influence of metallic cations, copper(II), iron(III), manganese(II), and chromium(III), on the sorption
of isoproturon and dimetomorph. We found that in the case of isoproturon, the presence of metallic cations does influence
the retention capacity of the soil sample. The sorption becomes very weak in the presence of copper and chromium, whereas
in the case of iron and manganese the sorption properties are slightly modified. 相似文献
3.
Banu JR Kaliappan S Rajkumar M Beck D 《Journal of environmental biology / Academy of Environmental Biology, India》2006,27(1):111-117
Approximately 400 KL of spent wash or vinasse per annum is generated at an average COD concentration of 100,000 mg/l, by over 250 distilleries in India. There is an urgent need to develop, assess and use ecofriendly methods for the disposal of this high strength wastewater. Therefore, an attempt was made to investigate a few aspects of anaerobic digestion of spent wash collected from a distillery. The study was carried out in a 4 L laboratory scale anaerobic mesophilic suspended growth reactor. After the successful startup, the organic loading was increased stepwise to assess the performance of the reactor. During the study period, biogas generated was recorded and the maximum gas generated was found to be 16.9 L at an Organic Loading Rate (OLR) of 38 g COD/L. A 500% increase in the Volatile Fatty Acid (VFA) concentration (2150 mg/L) was observed, when the OLR was increased from 38 to 39 g COD/L. During the souring phase the removal of COD, Total Solids (TS) and Volatile Solids (VS) were in the order of 52%, 40% and 46% respectively. The methane content in the biogas varied from 65% to 75%. 相似文献
4.
B. R. V. Narasimhan Satendra Kumar T. S. N. Sankara Narayanan 《Environmental Chemistry Letters》2011,9(2):243-250
The possibility of utilizing hydrochloric acid-based waste pickle liquor (WPL) and medium-grade pyrolusite ore to synthesize
manganese zinc ferrite was explored. The excess acidity of the WPL was neutralized using mild steel turnings. The unreacted
mild steel scrap and suspended solids were removed by filtration. Partial precipitation technique was employed to reduce the
impurities. The purified WPL was treated with medium-grade pyrolusite ore to prepare the leach liquor to which the required
quantities of ferrous chloride and zinc granules were added to maintain stoichiometry in the resultant compound. The hydroxy
carbonate of manganese, zinc and iron was precipitated by the addition of a hot solution (70°C) of sodium carbonate (20% v/v),
which upon sintering in argon atmosphere yielded manganese zinc ferrite. The addition of sodium lauryl sulfate (SLS) helped
in preventing agglomeration of the particles. Sintering at 450°C for 30 min in argon atmosphere has resulted in mixed phases
of (Zn,Mn,Fe) (Fe,Mn)2O4 and Mn3O4, which indicates lack of phase purity. Sintering at temperatures higher than 950°C for 5 h in argon atmosphere enabled complete
ferritization. The extent of ferritization was found to be a function of sintering time at 950°C. The manganese zinc ferrites
synthesized using WPL and medium-grade pyrolusite ore exhibited soft magnetic characteristics. 相似文献
5.
根表铁锰膜对不同生育期水稻吸收和转运As的影响 总被引:3,自引:0,他引:3
采用土壤盆栽试验法,研究不同生育期水稻根表铁锰膜形成及其对As吸收和转运的影响。结果表明,两个水稻品种YD6和NK57均在分蘖期形成的铁锰膜量最多,成熟期形成的铁锰膜量最少。水稻根系和茎叶吸收积累As随着水稻不同品种和不同生育期变化较大,As的吸收和积累与铁锰膜形成存在相关性。与分蘖期相比,YD6和NK57成熟期根系As含量分别减少81.6%和62.1%。孕穗期YD6和NK57茎叶As含量分别比分蘖期减少86.4%和65.5%,比成熟期减少87.8%和67.1%。分蘖期水稻根系和茎叶As含量与DCB-Fe或DCB-Mn浓度均呈显著的负相关关系,而孕穗期水稻根系和茎叶As含量与DCB-Fe浓度呈显著的正相关关系,说明不同生育期铁锰膜对水稻植株吸收和转运As的影响不同。两个水稻品种不同生育期,As均主要富集和分配在根表铁锰膜中,铁锰膜中As的分配比率达62.9%~84.9%。NK57从根表铁锰膜、根系和茎叶向籽粒转运As的能力比YD6强,籽粒中As含量是YD6的2.1倍。结果表明可以通过选育As低积累和低转运的水稻品种,来降低污染地区As对人体健康的威胁。 相似文献
6.
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
7.
The aim of this study is to determine the contents of aluminum, iron, manganese, nickel, copper, zinc, chromium, cadmium, lead, and mercury in sediments at 1–30?m depths of the Band?rma and Erdek Gulfs in the Southern Inner Shelf of the Marmara Sea. Sediment samples were collected from different depths (1?m, 5?m, 10?m, 20?m, 30?m) at each region in February 2008. Primary hydrographic conditions, such as temperature (6.6–14.5°C), salinity (22.6–26.875 psu), percentage of dissolved oxygen saturation (35–83 %), and pH (8.0–8.4) were recorded for each sampling point. Moreover the total organic carbon (0.5–2.9%) and the total calcium carbonate contents (0.8–60%) of sediment samples were determined. In surface sediments of both gulfs, Pb (21–62?mg?kg?1) and Cd (0.52–0.86?mg?kg?1) contents were determined to be higher than the shale average (Pb 20?mg?kg?1, Cd 0.2?mg?kg?1) while the other metal contents were measured to be lower in general. On the other hand, generally Hg (0.06–1.1?mg?kg?1) contents were higher than the shale average (0.3?mg?kg?1)at all of the examined stations in the Band?rma Gulf and lower than the shale average in the Erdek Gulf. 相似文献
8.
Zecong Yu Keke Xiao Yuwei Zhu Mei Sun Sha Liang Jingping Hu Huijie Hou Bingchuan Liu Jiakuan Yang 《Frontiers of Environmental Science & Engineering》2022,16(6):80
9.
Tong Li Ke Xiao Bo Yang Guilong Peng Fenglei Liu Liyan Tao Siyuan Chen Haoran Wei Gang Yu Shubo Deng 《Frontiers of Environmental Science & Engineering》2019,13(6):91
10.
Electrolytic manganese residue (EMR) is a type of solid waste discharged from the process that converts solid manganese carbonate of rhodochrosite into soluble Mn(II) and generates anode mud under electrolysis. The experimental material was a filtrate created by using distilled water as a dispersal agent for the EMR, followed by simple filtration. A calculated amount of sodium carbonate was added to recover the soluble Mn(II) via precipitation into manganese carbonate. Data showed that Mn concentration may be markedly decreased from 2069 to 36 mg/L, thereby reaching a recovery rate as high as 98%. Analysis demonstrated that precipitation of Mn(II) from a leached aqueous solution followed first-order kinetics. The findings indicate that the reaction rate constant decreased as temperature gradually rose and that its apparent activation energy Ea was ?10.48 kJ/mol. 相似文献
11.
Mishra S Ramteke DS Wate SR 《Journal of environmental biology / Academy of Environmental Biology, India》2007,28(4):851-856
Increased risk of ill-health and diseases has been associated with employment in the ferro-alloy factory. Since measurement of transition metals in human blood and hair along with respective exposure rates, provides a means of assessing individual risk, it has been the most important part of the study. In the study majority of the elements in the transition series, such as, vanadium (V), chromium (Cr), iron (Fe), manganese (Mn), cobalt, (Co) nickel (Ni), copper (Cu), zinc (Zn), molybdenum (Mo) and cadmium (Cd) were considered which are randomly emitted from the source, that is, manganese ore (used during ferro-alloy manufacturing process). The commonly available transition, metals, observed in biological samples of ferro-alloy workers, were found to be Fe, Zn, Co, Ni, Cu, Cr, Cd, V Mn and Mo in blood, while in hair, Mn, Fe, Zn, Co, Ni, Cu, Cr, Cd, V and Mo were present in decreasing order Surveillance of bio-concentration of these metals in workers, exposed to close proximity of the coke-ovens and smelting furnaces, revealed that the workers were prone to several physical disorders. 相似文献
12.
Accumulation and regulation of heavy metals by the intertidal snail Polinices sordidus 总被引:2,自引:0,他引:2
The gastropod Polinices sordidus was collected from an uncontaminated area in Quibray Bay, New South Wales, Australia, in 1990. The snails were exposed for 2 wk to polluted sediments collected from Port Kembla Harbour, Blackwattle Bay, Lake Illawarra, Lake Macquarie in New South Wales, Australia, and the Derwent River in Tasmania, Australia. Metal accumulation and regulation by this species were evaluated. Metal concentrations in snail tissues and total, EDTA and HCl-extractable metals in the sediments were compared. Copper concentrations were extremely varied in snails exposed to the same sediment. This was not the case for other matals tested. No accumulation of copper was found in snails exposed to different sediments. There was no zinc accumulation from sediments containing less then 10 mg Zn/g. P. sordidus could accumulate lead, manganese and iron from some of the sediments. Manganese concentrations in the snail tissues correlated with total, HCl-extractable and, more significantly, EDTA-extractable Mn in the sediments. P. sordidus was not considered to be a good bioindicator of copper and zinc contaimination in sediments; however, this species could be used as an indicator of lead and manganese contamination. 相似文献
13.
Singh KD Sharma S Dwivedi A Pandey P Thakur RL Kumar V 《Journal of environmental biology / Academy of Environmental Biology, India》2007,28(3):675-677
Molasses spent wash from cane-molasses based distilleries contains a brown coloured recalcitrantpolymer melanoidin, which if disposed untreated poses a great threat to environment. Microbial decolorization and chemical oxygen demand (COD) reduction was found to be dependent on specific carbon and nitrogen source. Under optimal condition of pH, carbon and nitrogen concentration for each treatment, it was found that Bacillus sp isolated from soil was capable of removing COD (85. 35%) and colour (81.10%) from distillery waste to the maximum extent after 9 days atpH 7 in the medium containing 0.5% peptone, 2% glucose and 10% (v/v), followed by Phanerochaete chrysosporium and lowest reduction was obtained by using native microbial consortium. 相似文献
14.
Youjun CHEN Feng XIAO Yongkang LIU Dongsheng WANG Ming YANG Hua BAI Jiong ZHANG 《Frontiers of Environmental Science & Engineering》2015,9(1):66
The continuous variations of dissolved oxygen (DO), manganese (Mn), pH, and their effect on manganese removal by different water treatment processes are investigated. The results show that the declined DO concentration and pH value in the bottom of reservoir results in the increasing release of Mn from sediment to source water. Manganese concentration increased from 0.1 to 0.4 mg·L-1 under the condition that DO concentration decreased from 12.0 to 2.0 mg·L-1 in raw water. The different water treatment processes exhibited different efficiency on manganese removal. The processes with recycling of the suspended sludge, low elevation velocity in settling tank and slow filter rate, will benefit the manganese removal. During a high release of manganese in raw water, traditional coagulation-sedimentation and filtration could not completely remove Mn, although granular activated carbon filtration (GAC) had been applied. At that case, preoxidation with chlorine or potassium permanganate (KMnO4) was necessary to address the high manganese concentration. 相似文献
15.
Fan Yang Junpeng Li Huan Wang Xiaofeng Xiao Rui Bai Feng Zhao 《Frontiers of Environmental Science & Engineering》2023,17(2):19
16.
Jingya SHEN Yuliang SUN Liping HUANG Jinhui YANG 《Frontiers of Environmental Science & Engineering》2015,9(6):1084-1095
Cobalt and copper recovery from aqueous Co(II) and Cu(II) is one critical step for cobalt and copper wastewaters treatment. Previous tests have primarily examined Cu(II) and Co(II) removal in microbial electrolysis cells (MECs) with abiotic cathodes and driven by microbial fuel cell (MFCs). However, Cu(II) and Co(II) removal rates were still slow. Here we report MECs with biocathodes and driven by MFCs where enhanced removal rates of 6.0±0.2 mg?L−1?h−1 for Cu(II) at an initial concentration of 50 mg?L−1 and 5.3±0.4 mg?L−1 h−1 for Co(II) at an initial 40 mg?L−1 were achieved, 1.7 times and 3.3 times as high as those in MECs with abiotic cathodes and driven by MFCs. Species of Cu(II) was reduced to pure copper on the cathodes of MFCs whereas Co(II) was removed associated with microorganisms on the cathodes of the connected MECs. Higher Cu(II) concentrations and smaller working volumes in the cathode chambers of MFCs further improved removal rates of Cu(II) (115.7 mg?L−1?h−1) and Co(II) (6.4 mg?L−1?h−1) with concomitantly achieving hydrogen generation (0.05±0.00 mol?mol−1 COD). Phylogenetic analysis on the biocathodes indicates Proteobacteria dominantly accounted for 67.9% of the total reads, followed by Firmicutes (14.0%), Bacteroidetes (6.1%), Tenericutes (2.5%), Lentisphaerae (1.4%), and Synergistetes (1.0%). This study provides a beneficial attempt to achieve simultaneous enhanced Cu(II) and Co(II) removal, and efficient Cu(II) and Co(II) wastewaters treatment without any external energy consumption. 相似文献
17.
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
18.
Lisbeth M. Ottosen Eduardo Arevalo Heinz Stichnothe Wolfgang Calmano 《Environmental Chemistry Letters》2006,3(4):164-168
Wastewater from wash down of boat hulls contains typically Cu, Zn and organometallic biocides, e.g. tributyltin (TBT). In
some cases this wastewater is led directly into the marine system. In the present paper, a cheap flocculation method (iron
flocculants) for removal of Cu and Zn from the wastewater is investigated and the method was shown successful. TBT concentration
in a sample from a German dockyard was also decreased during flocculation, but the TBT removed was already associated with
small particulates in the original sample. Low concentrations of heavy metals were obtained by flocculation: <0.05 mg Cu/l
and 0.2 mg Zn/l.
An erratum to this article can be found at 相似文献
19.
Total metal concentrations (Cu, Ni, Pb, Zn, Fe, and Mn) and their distribution in different chemical forms (speciation) were determined in sediments from the Adriatic Sea in order to evaluate contamination and mobility of metals. The study was carried out on marine sediments collected in two areas of the Adriatic Sea differently influenced by Po river waters. Metal distribution in the study area depends prevalently on water circulation and on organic matter distribution. Among metal levels, significant correlations between copper and zinc and between lead and nickel were found, suggesting common and specific sources. As regards metal speciation, the distribution of different chemical forms changes with the metal. The prevailing zinc phases, for example mobile forms, and sulphide together are greater than 50% of total metal. Nickel is mainly present in sediments as sulphide, and the preferential association of copper with organic matter is evident. Lead and manganese are preferentially found as mobile forms (more of 30% for lead, 40% or more for manganese). 相似文献
20.
Md. Abul Hashem Md. Shahruk Nur-A-Tomal Nil Ratan Mondal Md. Aminur Rahman 《Environmental Chemistry Letters》2017,15(3):501-506
Heavy metals in the environment may be toxic for human and animals. Tanneries are a source of pollution by heavy metals. There is little information on heavy metals pollution in tanneries, especially on metals produced by the process of hair burning and liming. Liming is the first stage of chemical treatment where animal hair or wool is removed with sodium sulphide and calcium oxide. Here we studied cow, goat, buffalo and sheep hair, conventional liming agents and liming wastewaters from several sources. Samples were acid-digested and aliquots were analysed by atomic absorption spectroscopy following APHA standard method to measure concentrations of arsenic, lead, cadmium, zinc, manganese and iron. Results show that the range of metal contents in hair or wool and liming agents are 1.3–8.2 mg/kg for arsenic, 0.02–21.8 mg/kg for lead, 17.7–121.0 mg/kg for manganese, 7.3–141.1 mg/kg for zinc and 119.6–10613.8 mg/kg for iron. Liming wastewaters contain 1.9–5.6 µg/L arsenic, 0.03–6.05 µg/L lead, 38.6–139.0 µg/L manganese, 144.0–171.5 µg/L zinc and 399.5–1069.0 µg/L iron. Cadmium was below detection limits. This is the first investigation that reveals that hair burning liming operation is a potential source of heavy metals in the environment. 相似文献