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Xu Zhen Liu Xi-Wei Ma Yin-Sheng Gao Hong-Wen 《Environmental science and pollution research international》2010,17(3):798-806
Background, aim, and scope
Nanomaterials have been used increasingly in industrial production and daily life, but their human exposure may cause health risks. The interactions of nanomaterial with functional biomolecules are often applied as a precondition for its cytotoxicity and organ toxicity where various proteins have been investigated in the past years. In the present study, nano-TiO2 was selected as the representative of nanomaterials and lysozyme as a representative for enzymes. By investigating their interaction by various instrumentations, the objective is to identify the action sites and types, estimate the effect on the enzyme structure and activity, and reveal the toxicity mechanism of nanomaterial. 相似文献2.
Hong-Wen Gao Jing Lin Wei-Ying Li Zhang-Jun Hu Ya-Lei Zhang 《Environmental science and pollution research international》2010,17(1):78-83
Purpose
Owing to the present complexity and difficulty of concentrated dye wastewater treatment, this work aimed to synthesize a reproducible waste-sorbing material for the treatment of wastewater by forming the dye-conjugating complex hybrid.Methods
The inorganic/organic hybridization was applied to prepare the objective material by immobilizing waster dye-Mordant blue 9 (MB) with barium sulfate (BaSO4). The composition and pattern of the formed material were determined by spectrometry and characterized by SEM and XRD, and their formation process was clarified. The adsorption of cationic dye-basic blue BO (BB) and copper ion was investigated..Results
The hybrid of MB alone into growing BaSO4 formed the pineapple-like particles while that of the MB/BB-conjugating complex was the rhombus material. The adsorption of BB on the MB–BaSO4 hybrid was probably attributed to ion-pair equilibrium and that of Cu2+ may result from the complexation. The treatment of dye and heavy metal wastewaters indicated that the MB hybrid material removed 99.8% BB and 97% Cu2+ and the dye-conjugating hybrid with growing BaSO4 100% MB, 99.5% BB, and 44% Cu2+.Conclusion
The waste MB–BaSO4 hybrid material is efficient to treat cationic dye and Cu2+ wastewater. The dye-conjugating hybridization method is the first to be advanced for in situ wastewater treatment, and it showed a combined effect for the removal of both organic dyes and heavy metals. 相似文献3.
Dan-Hua Zhao Hong-Wen Gao 《Environmental science and pollution research international》2010,17(1):97-105
Background, aim, and scope
Over the years, organic pollution in the environment has aroused people’s concern worldwide, especially persistent organic pollutants (POPs). Particularly in developing countries, plenty of concentrated organic wastewaters treated noneffectively are discharged into aquatic environments from chemical, textile, paper-making, and other industries to seriously threaten the surface and drinking water. The conventional wastewater treatment techniques are often helpless due to high cost with multilevel processing. Adsorption as an efficient method is often applied to the treatment of wastewater. The aim of this work is to develop an eco-friendly and cost-effective wastewater-sorbing material with weak acidic pink red B (APRB) and calcium carbonate (CaCO3) by reusing highly concentrated dye wastewater. 相似文献4.
Huang GL Mao Y Headley JV Sun HW 《Journal of environmental science and health. Part. B》2003,38(5):551-559
The toxicity of pentachlorophenol (PCP) on Chlorella pyrenidosa algae was investigated with specific attention given to possible variation of toxic effects with time. A concentration-effect relationship was observed in which there was significant inhibition of PCP on cell density and chlorophyll A content. The inhibition rate of PCP on cell density was dependent on exposure time. The IC50 values after exposure times of 2, 4 and 6 days for cell growth were 4.18 +/- 0.49, 3.49 +/- 0.40 and 3.30 +/- 0.26 mg/L, respectively. There was also inhibition of chlorophyll A production, which appeared to increase marginally with exposure time for a given concentration of PCP. The corresponding IC50 values on day 2, 4 and 6 were 2.30 +/- 0.12, 2.63 +/- 0.38 and 3.30 +/- 0.34 mg/L, respectively. The effect of PCP on nitrate reductase (NR), was first stimulation followed by an inhibition phase. It is postulated that the observed temporal changes in the activity of nitrate reductase (NR) may occur through the addition or loss of phosphorus in the NR protein. 相似文献
5.
In this study, laboratory experiments are conducted to compare the efficacy using several ozone-based advanced oxidation processes (AOPs), such as O3, O3/H2O2, and O3/UV, to treat landfill leachate. Raw leachate was initially coagulated by ferric chloride (FeCl3) at the experimental-determined optimal dosage of 900 mgl(-1), and the ozone-based AOPs were subsequently applied. Results indicate that all AOPs would result in a significant increase on the ratio of BOD5/COD from 0.06 to 0.5 at the applied ozone dosage of 1.2 gl(-1). The increase on biodegradability for ozonated leachate indicates that these AOPs would be beneficial to the subsequent biological treatment process. To better explain the alteration of high organic molecules after oxidation, ultrafiltration was used to separate the leachate by several molecular weight cutoffs (MWCO). The COD distribution for coagulated leachate is 34% for MWCO>10 kDa, 7% for MWCO between 5 and 10 kDa, 22% for MWCO between 1 and 5 kDa, and 37% for MWCO<1 kDa. Following ozonation or AOPs, the predominant distribution of COD would be obviously shifted to the MWCO less than 1000 gmol(-1) (72-85%) over the other MWCO ranges. In addition, Gel Permeation Chromatograph (GPC) analysis has showed a substantial agreement on the cleavage of larger organic compounds into smaller ones. O3/UV was found to be the most effective approach among these ozone-based AOPs to enhancing the biodegradability and eliminating the color of leachate. 相似文献
6.
An on-site solid-phase extraction, consisting of the sorption, the separation and the elution function units, was designed for in situ preconcentration of heavy metals ions. The D401 resin powder was employed as sorbent to capture Pb2+, Cu2+, Zn2+, Cd2+, Co2+, and Ni2+, and then they desorbed with 2 mol/L nitric acid as eluent. Under the optimized conditions, these heavy metals ions in West Lake, Taihu Lake, and Yangtze River of China were captured and then determined by ICP-OES with the recovery of 92.5% to 111.5%. The on-site solid-phase extraction achieved a quick preconcentration of heavy metals to avoid the transport and storage of a large volume water sample. It is suitable for in situ monitoring of water quality in mountains, tablelands or other remote areas. 相似文献
7.
Optimization of ethylenediamine-grafted multiwalled carbon nanotubes for solid-phase extraction of lead cations 总被引:1,自引:0,他引:1
Hu ZJ Cui Y Liu S Yuan Y Gao HW 《Environmental science and pollution research international》2012,19(4):1237-1244
Introduction
Ethylenediamine-grafted multiwalled carbon nanotubes (MWCNTs-EDA-I and MWCNTs-EDA-II) are optimized and employed to investigate the preconcentration of lead ions (Pb(II)) in trace level. 相似文献8.
Background, aim, and scope Dye pollutants are a major class of environmental contaminants. Over 100,000 dyes have been synthesized worldwide and more
than 700,000 tons are produced annually and over 5% are discharged into aquatic environments. The adsorption or sorption is
one of the most efficient methods to remove dye and heavy metal pollutants from wastewater. However, most of the present sorbents
often bear some disadvantages, e.g. low sorption capacity, difficult separation of spoil, complex reproduction, or secondary
pollution. Development of novel sorbents that can overcome these limitations is desirable.
Materials and methods On the basis of the chemical coprecipitation of calcium oxalate (CaC2O4), bromopyrogallol red (BPR) was embedded during the growing of CaC2O4 particles. The ternary C2O4
2––BPR–Ca2+ sorbent was yielded by the centrifugation. Its composition was determined by spectrophotometry and AAS, and its structure
and morphology were characterized by powder X-ray diffraction (XRD), laser particle-size analysis, and scanning electron microscopy
(SEM). The adsorption of ethyl violet (EV) and heavy metals, e.g. Cu(II), Cd(II), Ni(II), Zn(II), and Pb(II) were carried
out and their removal rate determined by spectrophotometry and ICP-OES. The adsorption performance of the sorbent was compared
with powder activated carbon. The Langmuir isothermal model was applied to fit the embedment of BPR and adsorption of EV.
Results The saturation number of BPR binding to CaC2O4 reached 0.0105 mol/mol and the adsorption constant of the complex was 4.70 × 105 M–1. Over 80% of the sorbent particles are between 0.7 and 1.02 μm, formed by the aggregation of the global CaC2O4/BPR inclusion grains of 30–50 nm size. Such a material was found to adsorb cationic dyes selectively and sensitively. Ethyl
violet (EV) was used to investigate the adsorption mechanism of the material. One BPR molecule may just bind with one EV molecule.
The CaC2O4/BPR inclusion material adsorbed EV over two times more efficiently than the activated carbon. The adsorption of EV on the
CaC2O4/BPR inclusion sorbent was complete in only 5 min and the sedimentation complete in 1 h. However, those of EV onto activated
carbon took more than 1.5 and 5 h, respectively. The treatment of methylene blue and malachite green dye wastewaters indicated
that only 0.4% of the sorbent adsorbed over 80% of color substances. Besides, the material can also adsorb heavy metals by
complexation with BPR. Over 90% of Pb2+, and approximately 50% of Cd2+ and Cu2+, were removed in a high Zn2+-electroplating wastewater when 3% of the material was added. Eighty-six percent of Cu2+, and 60% of Ni2+ and Cd2+, were removed in a high Cd2+-electroplating wastewater.
Discussion The embedment of BPR into CaC2O4 particles responded to the Langmuir isothermal adsorption. As the affinity ligand of Ca2+, BPR with sulfonic groups may be adsorbed into the temporary electric double layer during the growing of CaC2O4 particles. Immediately, C2O4
2– captured the Ca2+ to form the CaC2O4 outer enclosed sphere. Thus, BPR may be released and embedded as a sandwich between CaC2O4 layers. The adsorption of EV on the sorbent obeyed the Langmuir isothermal equation and adsorption is mainly due to the ion-pair
attraction between EV and BPR. Different from the inclusion sorbent, the activated carbon depended on the specific surface
area to adsorb organic substances. Therefore, the adsorption capacity, equilibrium, and sedimentation time of the sorbent
are much better than activated carbon. The interaction of heavy metals with the inclusion sorbent responded to their coordination.
Conclusions By characterizing the C2O4
2––BPR–Ca2+ inclusion material using various modern instruments, the ternary in situ embedment particle, [(CaC2O4)95(BPR)]
n
2n–, an electronegative, micron-sized adsorbent was synthesized. It is selective, rapid, and highly effective for adsorbing cationic
dyes and heavy metals. Moreover, the adsorption is hardly subject to the impact of electrolytes.
Recommendations and perspectives The present work provides a simple and valuable method for preparing the highly effective adsorbent. If a concentrated BPR
wastewater was reused as the inclusion reactant, the sorbent will be low cost. By selecting the inclusion ligand with a special
structure, we may prepare some particular functional materials to recover the valuable substances from seriously polluted
wastewaters. The recommended method will play a significant role in development of advanced adsorption materials.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
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