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Phosphorus (P) has been identified as a major cause of eutrophication. One feasible way to deal with P-containing wastewater is to employ advanced adsorbents with high P affinity. Towards this end, the loading of these sorbents onto a conductive scaffold would facilitate the introduction of an electric field into the reaction system thereby permitting a continuous-flow operation and improved P sorption kinetics. Here, the preparation and evaluation of an electroactive carbon nanotube (CNT) filter functionalized with cerium-based metal organic frameworks (Ce-MOF) is reported. Various advanced characterization techniques confirmed the successful fabrication of the Ce-MOF/CNT nanohybrid filter. The results suggested that the nanohybrid filter had a maximum P adsorption capacity of 22.41 mg g

This study focused on evaluating the use of powdered activated carbon (PAC) adsorption for the treatability of various odor compounds with different structures. The adsorption performance of 14 odor compounds under various PAC dosages were fitted with two isotherm models (the Langmuir and Freundlich models) to evaluate the adsorption ability. The results indicated that the adsorption capacities estimated from isotherm model predictions were not suitable for the evaluation of treatability of the odor compound due to the neglection of odor threshold. A novel assessment method, through the comparison of the residual concentration at an inflection point (where the downward trend of the odor compound residual concentration and PAC dosage curve starts to flatten) and the corresponding threshold concentration, was employed. This assessment method considered the different thresholds of the various odor compounds and their absorbability by PAC as well as the cost. The results indicated that only the sulfur odor compounds, including dimethyl disulfide, diethyl disulfide and dimethyl trisulfide, were not suitable for PAC treatment. Other odor compounds could be treated by PAC with varying success. The correlations between the adsorption capacity and the treatability of various odor compounds and their properties, including the coefficient between octanol and water (LogKw), solubility, molar refractivity (MR), dipole and volume, were also evaluated using the Pearson and Spearman correlation analysis. The results indicated that there were not significant correlations between the adsorption capacity and the properties of the odor compounds, while there were significant correlations between the treatability and LogKw, MR and volume. The odor causing compound with a larger LogKw, MR and volume was more suitable to be treated by PAC.

A new, environmental friendly, polysilicate ferric manganese (PSFM) coagulant, composed of Fe, Mn and Si, was designed and developed. As part of the process, the PSFM flocs were then deposited onto an ultrafiltration (UF) membrane to increase the removal of active dyes and its antifouling properties in the presence of the active dye was tested. Influencing factors, such as dosage of coagulant and solution pH, were systematically investigated and included as the process optimization. The results show that PSFM flocs were well distributed on the membrane surface and a dense and homogeneous deposition layer was formed under optimal conditions. According to the characterization of PSFM floc by Fourier infrared (FTIR) and X-ray photoelectron spectroscopy (XPS), the major phase of PSFM floc is determined to be Mn x Fe y Si z O w (OH) i and the functional groups of this component contribute positively to the coagulation performance. The removal rate of the active yellow dye reached 86% at pH 5.0 with small and regular floc formed in the dense deposition layers. At pH 11.0 loose deposition layers were formed by large flocs and the removal of the active yellow dye reduce to 11%. Therefore, PSFM has a commendable potential to be used for producing a kind of deposited UF membrane with an excellent performance by controlling the forms of flocs and the deposition layers, which is the key mechanism to achieve a high efficiency for removal of active yellow dye Refereed/Peer-reviewed

Due to the extensive existence of tetracyclines (TCs), struvite (MgNH4PO4·6H2O) recovery from swine wastewater will pose TCs-pharmacological threats to the agricultural planting and environment. This study investigated the influences of dissolved organic matters (DOM), as an important medium in the wastewater, on TCs transport during struvite recovery from swine wastewater. Compared to TCs concentrations of 1.49–2.16 μg/g in the solids obtained from synthetic wastewater, the existence of DOM significantly enhanced TCs contents in the products with the values of 360–742 μg/g. DOM was fractionated into four size fractions with different molecular weight cut-off, i.e. FDOM1 (30 kDa-0.45 μm), FDOM2 (5–30 kDa), FDOM3 (1–5 kDa) and FDOM4 (

Spatial and seasonal variations of arsenic species in Lake Taihu (including Zhushan Bay, Meiliang Bay, Gonghu Bay, and Southern Taihu) were investigated. Relatively high levels of total arsenic (TAs) and arsenate (As(V)) were observed in hyper-eutrophic regions during summer and autumn, which is attributed to exogenous contamination and seasonal endogenous release from sediments. The distributions of TAs and As(V) were significantly affected by total phosphorus, iron, manganese, and dissolved organic carbon. Arsenite (As(III)) and methylarsenicals (the sum of monomethylarsenic acid (MMA(V)) and dimethylarsenic acid (DMA(V))), mainly from biotransformation of As(V), were affected by temperature-controlled microalgae activities and local water quality parameters, exhibiting significantly higher concentrations and proportions in hyper-eutrophic and middle eutrophic regions during summer compared to mesotrophic region. The eutrophic environment, which induces changes in the main water quality parameters such as phosphorus, chlorophyll-a, iron, manganese, and dissolved organic carbon, can favor the biogeochemical cycling of arsenic in the aquatic systems.

The character of dissolved organic matter (DOM) in source waters from two countries (Australia and China) was investigated using an extended fractionation technique by combining resin adsorption, ultrafiltration and high performance size exclusion chromatography. There are distinctive chemical characteristics associated with DOM origins. Australian sourced DOM had higher hydrophobic acid (HoA) content and exhibited a more pronounced humic character, indicating a higher influence from allochthonous organics (decayed plant bodies from vegetated catchments). The higher content of hydrophobic base and neutral components found in Chinese DOM, may be attributed to the effects of increasing pollution caused by the rapid urbanization in China. The molecular weights (MWs) of aquatic HoA are predominantly in the moderate (e.g. 1–10 kDa) or small (e.g.

The pollutants in urban storm runoff, which lead to an non-point source contamination of water environment around cities, are of great concerns. The distributions of typical contaminants and the variations of their species in short term storm runoff from different land surfaces in Xiamen City were investigated. The concentrations of various contaminants, including organic matter, nutrients (i.e., N and P) and heavy metals, were significantly higher in parking lot and road runoff than those in roof and lawn runoff. The early runoff samples from traffic road and parking lot contained much high total nitrogen (TN 6–19 mg/L) and total phosphorus (TP 1–3 mg/L). A large proportion (around 60%) of TN existed as total dissolved nitrogen (TDN) species in most runoff. The percentage of TDN and the percentage of total dissolved phosphorus remained relatively stable during the rain events and did not decrease as dramatically as TN and TP. In addition, only parking lot and road runoff were contaminated by heavy metals, and both Pb (25–120 μg/L) and Zn (0.1–1.2 mg/L) were major heavy metals contaminating both runoff. Soluble Pb and Zn were predominantly existed as labile complex species (50%–99%), which may be adsorbed onto the surfaces of suspended particles and could be easily released out when pH decreased. This would have the great impact to the environment.

For pollution monitoring,we developed a new combined fractionation technique (CFT) to characterize dissolved organic matter (DOM) in natural water by combining resin adsorption (RA) and ultrafiltration (UF) with 3Dfluorescence measurement. We tested the new technique on 4 polluted and 4 unpolluted samples. The 3Dfluorescence characteristics of size sub-components in the hydrophobic acid (HPOA) fraction could distinguish unpolluted from polluted DOM. The unpolluted HPOA fraction was composed of a single dominant size component-peak A (fulvic-like, around Ex240/Em410 nm) material with relatively large molecular weight (MW) (>10 kDa). In comparison, the HPOA in polluted DOM contained another predominant size component with lower MW (

Understanding the environmental safety and human health implications of engineered nanoparticles (ENPs) is of worldwide importance. As an important ENPs, engineered nano-TiO(2) (Enano-TiO(2)) may have been substantially deposited in aquatic sediments because of its widely uses. Sediment pore surface properties would be thus significantly influenced due to the large surface area of Enano-TiO(2). In this study, Enano-TiO(2) was found to greatly impact on sediment pore surface properties. The attachment of Enano-TiO(2) particles to sediment surfaces enhanced markedly BET specific surface area and t-Plot external specific surface area, and thereby increased sediment phosphorus (P) adsorption maximum (S(max)). Contrarily, the fill of Enano-TiO(2) particles into the micropores of sediments could significantly reduce t-Plot micropore specific surface area, and cause slight decrease in sediment P binding energy (K). Clearly, P sorbed in sediment would be easily released because of the decreasing P binding energy of the sediment with elevated Enano-TiO(2). Enano-TiO(2) would thus cause aggravated endogenous pollution in water if such sediment was re-suspended on disturbance. The results obtained in this study contribute to our increasing knowledge of how to regulate physicochemical behavior of pollutants in sediments under the influences of Enano-TiO(2) and/or similar ENPs.

Batch experiments were conducted to assess the effects of Cu(II) and Zn(II) on the biosorption of Pb(II) ions by fresh tissues of Myriophyllum spicatum. The biosorption of Pb(II) was examined for single, binary and ternary solutions at different initial concentrations and different pH values. The experimental results showed that the biosorption capacity increased with increasing pH from 2.0 to 6.0. Both Cu(II) and Zn(II) ions were found to have an adverse effect on the biosorption of Pb(II). The biosorption equilibrium data for single-metal solution were fitted to three isotherm models: Langmuir, Freundlich and Sips, and the Sips isotherm model gave the best fit for the experimental data. The maximum biosorption of Pb(II) in Pb–Cu binary system decreased with increasing concentration of copper ions, and the biosorption equilibrium data for the binary metal solution fitted the Langmuir competitive model well. Comparison between biosorption of Pb(II) and Cu(II) by M. spicatum in the binary solution could lead to the conclusion that the biosorbent (M. spicatum) has no preference of Pb(II) over Cu(II). Fourier transform infrared (FT-IR) spectroscopy was used to characterize the interaction between M. spicatum and Pb(II) ions. The results revealed that the carboxyl, hydroxyl and carbonyl groups are the main binding sites for Pb(II).

Iron oxides coated on Fe-0 core-shell nanospheres (nIOCl) were synthesized through the reduction of ferrous sulfate aqueous solution by sodium borohydride at ambient atmosphere. The catalyst was highly effective for the degradation of humic acid (HA) in the presence of H2O2 and UVA at neutral pH. Under deoxygenated conditions in the dark, the generation of hydroxyl radicals in aqueous nIOCl dispersion verified its galvanic cell-like performance, which enhanced the interfacial electron transfer and led to its higher reactivity. By the total organic carbon, the absorbance Of UV254, FTIR, the molecular weight distribution and the chemical fractional character analysis, the degradation process of HA was shown to proceed by the disappearance of aromaticity, the increase of hydrophilic fraction and aromatic ring openings into CO2 and small organic acid. The treated HA showed much lower reactivity toward chlorine and the disinfection byproduct (DBP) formation potential was also greatly reduced. Moreover, it was found that the DBP formation potential more depended on the structure of the intermediates of HA degradation than TOC removal. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.

Characterizing natural organic matter (NOM), particles and elements in different water treatment processes can give a useful information to optimize water treatment operations. In this article, transformations of particles, metal elements and NOM in a pilot-scale water treatment plant were investigated by laser light granularity system, particle counter, glass-fiber membrane filtration, inductively coupled plasma-optical emission spectroscopy, ultra filtration and resin absorbents fractionation. The results showed that particles, NOM and trihalomethane formation precursors were removed synergistically by sequential treatment of different processes. Pre-ozonation markedly changed the polarity and molecular weight of NOM, and it could be conducive to the following coagulation process through destabilizing particles and colloids; mid-ozonation enhanced the subsequent granular activated carbon (GAC) filtration process by decreasing molecular weight of organic matters. Coagulation-flotation and GAC were more efficient in removing fixed suspended solids and larger particles; while sand-filtration was more efficient in removing volatile suspended solids and smaller particles. Flotation performed better than sedimentation in terms of particle and NOM removal. The type of coagulant could greatly affect the performance of coagulation-flotation. Pre-hydrolyzed composite coagulant (HPAC) was superior to FeCl3 concerning the removals of hydrophobic dissolved organic carbon and volatile suspended solids. The leakages of flocs from sand-filtration and microorganisms from GAC should be mitigated to ensure the reliability of the whole treatment system.

Dissolved organic matter (DOM) and its potential to form disinfection by-products (DBPs) during water treatment are of great public health concern. Understanding the seasonal changes in DOM composition and their reactivity in DBP formation could lead to a better treatment of drinking water and a more consistent water quality. DOM from the East-Lake, a reservoir in the south-China, was fractionated and characterized by XAD resin adsorption (RA) and ultrafiltration (UF) techniques during different seasons within a year. The properties of chemical fractions (isolated by RA) appeared more stable than those of physical fractions (separated by UF) throughout the sampling period. The relative contribution of each chemical fraction to the total dissolved organic carbon (DOC), UV254 absorbance and trihalomethane formation potential (THMFP) remained relatively constant across the sampling period. However, the physical (molecular weight) fractions of the DOM exhibited large seasonal changes in UV254 and THMFP. Compared to the parameter of DOC, the THMFP and specific THMFP (STHMFP) of either chemical or physical fractions were more variable. In terms of DOC concentration, the hydrophobic acids (HoA) and hydrophilic matter (HiM) dominated in the DOM in most of the seasons; while the components with molecular weight of 10-30 kDa and less than I kDa were the predominant physical fractions. (c) 2007 Published by Elsevier B.V.