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Magnetic biochar composites (MBC) were developed by a simple one-step pyrolysis method using Fenton sludge waste solid and carboxymethyl cellulose sodium. Detailed morphological, chemical, and magnetic characterizations corroborate the successful fabrication of MBC. Batch adsorption experiments show that the synthesized MBC owns high-efficiency removal of Pb(II), accompanied by ease-of-separation from aqueous solution using magnetic field. The experiment shows that the equilibrium adsorption capacity of MBC for Pb(II) can reach 199.9 mg g−1, corresponding to a removal rate of 99.9%, and the maximum adsorption capacity (qm) reaches 570.7 mg g−1, which is significantly better than that of the recently reported magnetic similar materials. The adsorption of Pb(II) by MBC complies with the pseudo second-order equation and Langmuir isotherm model, and the adsorption is a spontaneous, endothermic chemical process. Investigations on the adsorption mechanism show that the combination of Pb(II) with the oxygen-containing functional groups (carboxyl, hydroxyl, etc.) on biochar with a higher specific surface area are the decisive factors. The merits of reusing solid waste resource, namely excellent selectivity, easy separation, and simple preparation make the MBC a promising candidate of Pb(II) purifier.

Metal-free activation of peroxydisulfate (PDS) for degrading organic pollutants in water has received increasing attention because it can prevent secondary pollution. However, most of the catalysts that are efficient are derived from non-renewable fossil resources, are very expensive and have complex preparation processes. Also, the emerging non-radical mechanism is still unclear. Herein, 3D sucrose-derived N-doped carbon xerogels (NCXs) were synthesized by a simple and sustainable hydrothermal process and then employed as novel metal-free PDS activators to degrade organic pollutants. The structure, composition and performance of NCXs were regulated by changing the carbonization temperature. The sample carbonized at 900 °C (NCX900) exhibited the best catalytic performance, completely removing bisphenol A in 60 min. Quenching experiments and linear sweep voltammograms demonstrated that PDS was activated mainly through an electron-transfer non-radical mechanism. It was found that graphitic N played a critical role in activating PDS. With this non-radical mechanism, the NCX900/PDS system could adapt well to the wide pH range (3–11) and high Cl− concentration; it selectively oxidized organic pollutants with low ionization potentials. This work provides a sustainable approach to the low-cost and efficient metal-free catalysts for wastewater treatment.

In this work, photocatalysts with a novel S-scheme heterojunction were fabricated by coupling MOF-derived TiO2 with porous g-C3N4 (MTO/PCN). The S-scheme heterojunction with matching band gap possesses different advantageous properties, which can not only inhibit photo-generated charge recombination, but also reserve outstanding redox ability. As expected, superior hydrogen evolution efficiency of 40-MTO/PCN was obtained in a TEOA-containing aqueous solution and pure water, which were 5252.9 and 974.6 μmol h−1 g−1, respectively. Meanwhile, the hybrid can also serve as a bifunctional catalyst for H2 generation (2137.3 μmol h−1 g−1) and organic contaminant removal (the RhB purification efficiency: 35.24%). This work furnishes a feasible method for devising bifunctional photocatalysts that can simultaneously produce hydrogen and purify wastewater to provide both energy-saving and environmental restoration functions.

This study used the officially released data by the Chinese air quality monitoring network to analyze the pollution characteristics of six air pollutants (PM2.5, PM10, SO2, NO2, CO, and O3) for 29 cities in the Central Plains Economic Zone (CPEZ; China) in 2015. During 2015, serious particulate matter (PM) pollution often occurred, and the concentrations of PM2.5 and PM10 were 77 μg m−3 and 128 μg m−3, respectively. Air pollutants were at higher concentrations in the northern cities than those in the southern region of the CPEZ, and the correlation among the cities indicated that there was regional pollution in CPEZ. Generally, PM, SO2, NO2, and CO showed similar seasonal characteristics and the highest and lowest concentrations appeared in winter and summer, respectively. In addition, we used the HYSPLIT model and trajStat model to identify the potential source contribution function and concentration-weighted trajectory of Zhengzhou, the central city of CPEZ. More serious air pollution occurred when air masses were transported from the west of the CPEZ. Shaanxi Province, Hubei Province, Anhui Province and the northwest of the CPEZ were found to be the main exogenous sources of total PM with contributions of > 100 μg m−3 PM2.5 and > 180 μg m−3 PM10. Therefore, the concentrations of PM in 2015 at Zhengzhou were probably influenced by both long-distance transmission and local emissions.

The major challenges of clean energy and environmental pollution have resulted in the development of photocatalysis technologies for energy conversion and the degradation of refractory pollutants. Herein, a novel CdSe/Se/BiOBr hydrangea-like photocatalyst was used to produce hydrogen peroxide (H2O2) and degrade ciprofloxacin (CIP). The Z-scheme heterojunction structure of the photocatalyst and the doping of selenium (Se) led to the efficient separation of electron-hole pairs and charge transfer. The optimized sample of 2 wt% CdSe/Se/BiOBr produced 142.15 mg·L−1 rate of H2O2, which was much higher than that produced by pure BiOBr (89.4 mg·L−1) or CdSe/Se (10.9 mg·L−1). Additionally, almost 100 % of CIP was degraded within 30 min, with a first order rate constant of nearly 5.35 times that of pure BiOBr and 81.44 times that of pure CdSe/Se. The excellent removal efficiency of CIP from natural water matrices confirmed that the composites are promising for the removal of contaminants from natural waterways. Based on trapping experiments, electron spin resonance spectra (ESR) spectroscopy, and density functional theory (DFT) calculations, the photocatalytic mechanisms of H2O2 and CIP degradation by the Z-scheme CdSe/Se/BiOBr composites were proposed. Overall, the dual-functional CdSe/Se/BiOBr composite could potentially be applied for photocatalytic production of H2O2 and treatment of organic pollutants in water.

During three sampling periods in 2014, systematic investigations were conducted into contamination profiles of ten organophosphate flame retardants (OPFRs) in both suspended particulate phase and water phase in the Yellow River (Henan Area). This research shows that OPFRs exist at lower concentrations in the suspended phase than in the water phase. The median concentration of 10 OPFRs (∑10OPFRs) in the suspended particulate phase was 62.5 ng/g (fluctuating from ND to 6.17 × 103 ng/g, dw), while their median concentration in the water phase was 109 ng/L (fluctuating from 35.6 to 469 ng/L). Among the selected 10 OPFRs, triethylphosphate (TEP), tris(1-chloro-2-propyl) phosphate (TCPP), and tris(2-chloroethyl) phosphate (TCEP) were the predominant compounds in the water phase (occupying 91.6% of the ∑10OPFRs), while TCPP, TCEP, and tri-o-tolyl phosphate (o-TCP) were the most common in the suspended particulate phase, accounting for 90.1% of the ∑10OPFRs. Across the three sampling periods, there was no significant seasonable variation for OPFRs either in the water phase or in the suspended particulate phase, except for TCEP and TCPP in the water phase. Compared with research findings relating to concentrations of OPFRs around China and abroad, the OPFRs of the Yellow River (Henan Area) in the water phase were at a moderate level. Suspended particles (SS) had a very important impact on the transportation of OPFRs in the studied area, with about 83.9% of ∑10OPFRs inflow attributed to SS inflow and about 81.7% of ∑10OPFRs outflow attributed to SS outflow. The total annual inflow and outflow of OPFRs were 7.72 × 104 kg and 6.62 × 104 kg in the studied area, respectively.

The efficient removal of heavy metals from aqueous environment is imperative and challenging. A novel ternary composite constructed of diaminopyridine polymers, graphene oxide, and ferrite magnetic nanoparticles was designed by a facile in situ polymerization strategy for the removal of Pb(II) from aqueous solution. Detailed characterization of morphological, chemical, and magnetic properties was employed systematically to confirm the formation of the composite material. Batch adsorption experiment studies suggested that the composite was an excellent adsorbent for Pb(II) which was easily collected after use via exposure to an external magnetic field for 30 s. The effects of different parameters such as solution pH, adsorbent dosage, contact time, initial Pb(II) concentration, temperature, and co-existing ions were examined. The maximum adsorption capacity at pH = 5 was estimated to be 387.2 mg g-1 at 298 K by the Langmuir isotherm model, accompanied by favorable adsorption recyclability according to the investigation of regeneration experiments. Thermodynamic studies revealed that the Pb(II) adsorption via our ternary composite was endothermic and spontaneous. The corresponding removal performance for effluent containing Pb(II) from the battery industry was successfully examined. The present results indicated that our designed adsorbent is beneficial to the practical Pb(II) removal in wastewater purification.

This study investigated particle size and density distributions of polycyclic aromatic hydrocarbons (PAHs) in two surface sediments (JZ and KF), collected from the Yellow River of Henan section, Ch...

The historical trends and spatial distributions of 15 polycyclic aromatic hydrocarbons (PAHs) in sediments from the upper reach of the Huai River were investigated. The concentrations of total PAHs (ΣPAHs) in the surface sediments varied from 3.96 to 379 ng/g (average: 65.3 ng/g). PAHs in the surface sediments of the studied area were at a low level compared with some other rivers around the world. The component characteristics showed that four-ring PAHs were predominant. The principal component analysis-multiple linear regression (PCA/MLR) showed that PAHs in the surface sediments primarily originated from coal combustion and vehicular emissions, which accounted for 62.7% and 37.3% of ΣPAHs, respectively. The concentration of ΣPAHs in the sediment core ranged from 2.31 to 21.9 ng/g with deposition flux ranging from 1.91 to 33.3 ng/cm2/year. The historical pattern of PAHs correlated with the Chinese socioeconomic conditions during 1912–2014, confirming that PAHs are a sensitive tracer for anthropogenic activity. Since the 1980s, there was a sharp increase in PAHs concentrations in the studied core. PCA/MLR showed that PAHs in the sediment core were mainly from the burning of fossil fuels. The concentration of PAHs in the surface sediment and sediment core was affected by the content of total organic carbon and black carbon. The result revealed in this study could serve as a reference for the development of relevant remedial strategies for the management of the Huai River.

Herein, we fabricated an ultra-light graphene aerogel/Bi2WO6 (GA/BW) photocatalyst with macroscopic 3D architecture via in-situ synthesis, which had preferable activity for organic wastewater purification. We carefully characterized the physical and chemical properties of this macroscopic 3D architecture, finding that the flower-like Bi2WO6 (BW) uniformly loaded on the surface of GA, improving the visible light absorption performance, photon-generated carrier separation efficiency and organic contaminants adsorption ability, as well as photocatalytic ability compared with that of pure BW powders. When the mass ratio of GA and BW is 6:8, the degradation efficiency of rhodamine B (RhB) and sulfanilamide (SN) can reach 97.49% and 55.81% in 120 min, respectively. The as-prepared GA/BW composite is ultra-light and suitable for practical wastewater purification due to its flexibility and recyclability. The trapping experiments involved the main active species in the photocatalytic process were carried out and the results indicated that the h+ is the dominant oxidative species for the degradation of RhB.

Black carbon (BC) in surface sediments from Henan section of Yellow River and Huaihe River, China, was determined. Average content of BC in Huaihe River was 0.33%, higher than that in Yellow River ...

A total of 150 samples were collected from 25 sites in the Yellow River of Henan Province during 2014 to demonstrate the impact of suspended sediment (SS) load on the behavior of semi-volatile organic compounds (SVOCs) in the Yellow River. The average concentrations of SS ranged from

Solar-driven water evaporation plays an important role in the recycling of low-energy water resources. Here, we have prepared porous hydrophilic/hydrophobic cellulose graphene aerogel (CGA) to achieve efficient water recycling in solar-driven desalination and purification of heavy metal wastewater. The aerogel can reach water evaporation of 7.2 kg·m-2 for 4 h from simulated or actual seawater under 1 sun irradiation, which meets the daily water demand of two adults. Due to the interfacial evaporation and the formation of hydrogen and chelating bonds between heavy metal ions and oxygen-containing functional groups, CGA can effectively reduce the amount of heavy metal sewage to obtain water without biotoxicity. The efficient water recycling of aerogel is mainly attributed to the photothermal conversion of hydrophobic reductive graphene oxide (rGO), the interconnected porous structure formed by random stacking and cross-linking of hydrophilic cellulose sheets as well as holes in it serve as supply channel of water evaporation. In addition, ambient factors such as wind, humidity and ambient temperature boost the water evaporation of CGA in open system, while in closed system reducing the light reflection of condensed water and the relative humidity of the space is more conducive to improving evaporation efficiency.

Herein, photocatalytic degradation of levofloxacin hydrochloride (LVF) by a simple surface hydroxyl strategy on BiOBr photocatalyst was studied under simulated visible light irradiation. Interestingly, the BiOBr contained abundant hydroxyl groups following its modification with glucose, which enhanced the photocatalytic degradation of levofloxacin hydrochloride (LVF). The degradation efficiency of LVF over the optimized composite of BiOBr-5 could reach 91.67% in 20 min, which was much higher than that of pristine BiOBr (59.26%). Following, the biotoxicity of antibiotics to Escherichia coli DH5a could be eliminated after LVF photocatalytic degradation. This strategy proposed in this work can provide new ideas for tuning the surface structures of photocatalysts via specific functional groups for the highly efficient degradation and efficient removal of antibiotics in wastewater.

Sludge properties are critical to the treatment performance and potentially correlate with nitrous oxide (N

For the practical capture of heavy metal ions from wastewater, fabricating environmental friendly adsorbents with high stability and super adsorption capacity are pursuing issue. In this work, we develop magnetic supramolecular polymer composites (M-SMP) by using a simple two-step hydrothermal method. Systematical characterizations of morphological, chemical and magnetic properties were conducted to confirm the formation of M-SMP composites. The resulting M-SMP composites were applied to remove Pb(II) from aqueous solution and from real battery wastewater, and easy separation was achieved using a permanent magnet. By investigating the effects of various parameters, we optimized their operating condition for Pb(II) adsorption by the M-SMP. The uptake of Pb(II) onto M-SMP fitted well the pseudo-second-order and Langmuir isotherm models, and favourable thermodynamics showed a spontaneous endothermic process. The SMP endowed M-SMP with ultrahigh adsorption capacity for Pb(II) (946.9 mg g−1 at pH = 4.0, T = 298 K), remarkable selectivity, satisfactory stability and desirable recyclability. In Pb-contaminated lead-acid battery industrial wastewater, the concentration of Pb(II) declined from 18.070 mg L−1 to 0.091 mg L−1, which meets the current emission standard for the battery industry. These merits, combined with simple synthesis and convenient separation, make M-SMP an outstanding scavenger for the elimination of industrial Pb(II) wastewater.

The occurrence and spatial distribution of priority pharmaceuticals (PPs) in water samples from the Yellow River and the Huai River in the Henan region of China were investigated in this study. The concentration of the total PPs (ΣPPs; sum of the 10 observed PPs) ranged from not detected to 3474 ng L−1 in samples from the Yellow River and from 4.35 to 146 ng L−1 in samples from the Huai River. The level of the ΣPPs in the Huai River was much lower than that found in the Yellow River. The composition of the PPs differed between the two rivers. Norfloxacin, carbamazepine, and 5,5-diphenylhydantoin were detected at high concentrations in the Yellow River, whereas sulfamethazine, ampicillin trihydrate, carbamazepine, and 5,5-diphenylhydantoin were the dominant species in the Huai River, suggesting there were different pollution sources. In comparison to other studies around China, most of the PPs in water samples from the Yellow River and the Huai River were at low concentrations, except for norfloxacin and ofloxacin. There were significant seasonal variations among the PPs in water samples from the Huai River, whereas spatial distinctions were recorded among the PPs in the Yellow River. Dissolved organic carbon content did not correlate with the PPs in the studied area.

This study was conducted in order to explore the seasonal characteristics, climate impact and source of PM2.5 in Xinxiang, China. Daily PM2.5 samples were collected at urban site from January to December in 2015. Average PM2.5 concentration was 100.6 ± 65.8 μg m−3 in Xinxiang, which was several times higher than China Ambient Air Quality Standards (GB3095-2012). Secondary inorganic aerosols (SIA) constituted 70% of the total ionic concentrations. The average concentration of SO42- was 6.4 ± 12.0 μg m−3, which ranked the highest among the water-soluble ions analyzed. Seasonal variations of PM2.5 and its major chemical components were significant, most of them with high values in winter and the lowest values in summer, especially with heavier PM2.5 events (more than 200 μg/m3) in December. SIA and OC on polluted days were 2.1–2.3 times higher than those of on clean days. It was estimated that Fe, Li, Na, Mg, Al, K, Ca and Sr were emitted from crustal sources and Pb, Cr, Ni, Cu, Zn, As, Cd and V were emitted from anthropogenic emissions using the EF values. Analysis using the tracer and PCA/MLR revealed that vehicle exhausts were the most important source of PM2.5, which contributed 26.9% of PM2.5 over the whole study period. This study provides detailed composition data and first comprehensive analysis of PM2.5 in Xinxiang during a whole year.

The levels, spatial variation, congener profiles, impact factors, and ecological risk of polychlorinated biphenyls (PCBs) in the sediment from the Yellow River of Henan section, China, were investigated in this paper. Total concentration of 31 PCBs and seven indicator PCBs varied from ND to 1015 pg g-1 and ND to 423 pg g-1, respectively. Compared with other aquatic environments around China, PCB levels in the studied area were relatively low. Spatial variations revealed that tributaries possessed higher PCB levels, in comparison to mainstream, which acted as input sources of PCBs in the mainstream. The homolog profiles were dominated by lighter PCBs (Tri-PentaCBs), contributing above 70% of total PCBs. Correlation analysis between PCB concentrations and total organic carbon indicated that local input or atmospheric deposition was the primary controls of spatial variation of PCBs. According to simple sediment quality guidelines (SQG), the risks posed by PCBs in the sediments might be negligible.

The development of cost-effective dual-function photocatalytic materials to advance clean energy generation and storage combined with superior pollutant degradation performance has thus far remained challenging. For this study, potassium hexafluorophosphate (KPF6) was introduced to modify BiOBr via a simple one-pot hydrothermal method, where uniformly dispersed KPF6 on BiOBr nanosheets improved H2O2 yields and the pollutant degradation performance. Such materials have proven to be critical for low bandgap and enhanced surface charge separation for efficient H2O2 production. The optimized sample of 20 wt% KPF6/BiOBr showed a H2O2 production rate of 53.36 mg·L–1, which was much higher than that of pure BiOBr (27.19 mg·L–1). Nitroblue tetrazolium chloride (NBT) superoxide radical detection results suggested that two-step single-electron oxygen reduction was the primary pathway. More importantly, discarded polyethylene bags from supermarkets have been decomposed though the in-situ generation of H2O2 using KPF6/BiOBr materials, and the mass loss of plastics was 2.33 times higher than that of the pure BiOBr. This research offers new perspectives toward the development of new functionalized materials for H2O2 production, while improving capacities for the degradation of plastics.

Coupling adsorption and advanced oxidation processes (AOPs), two widely used wastewater treatment technologies, has been an attractive idea pursued by many researchers. Although many studies have demonstrated that adsorption could facilitate AOPs such as persulfate (PS) activation, the inhibitory effect of adsorption on PS activation was ignored. In this work, both as adsorbents and catalysts, sucrose-derived carbon xerogels (CXs) were prepared to investigate the effect of adsorption on PS activation. The results showed that the specific surface areas (SSAs) and N contents of CXs varied with the HCl concentration. Among different CXs, CX-0.5 with the highest SSA and N content exhibited the highest adsorption capacity and catalytic activity for acid orange 7 (AO7) degradation by simultaneously adding CXs and PS, where the promoting effect of adsorption on catalysis was found. Quenching tests demonstrated that degradation of pollutants in the CX-0.5/PS system were mainly by nonradical pathway. However, the catalytic activities of CXs were inhibited after the pre-adsorption of AO7 on CXs. Comparing the molecular structures of several compounds, the sulfonic group on chemicals might play a crucial role in the inhibitory effect. We concluded that if CXs have the same adsorption sites for pollutants and PS, adsorption of pollutants would inhibit the catalytic PS activation. These findings provided a comprehensive understanding of the effect of adsorption on AOPs, which had a significant guidance for future researches and applications.

Halogenated flame retardants (HFRs), mainly encompassing polybrominated diphenylethers (PBDEs), dechlorane plus (DP) and emerging bromine flame retardants (EBFRs), are widely employed nowadays in daily lives. However, limited knowledge has been gained to date on the concentrations and distributions of HFRs in particular within certain regions. In the present study, legacy and emerging HFRs were systematically measured in suspended particle matter (SPM) and sediments collected in 2014 from the middle and lower reach of the Yellow River in Henan province. The total concentrations of HFRs in SPM among the three seasons were 42.2±91.2ngg-1, which was far higher than the corresponding values of HFRs in sediments (1.82±2.94ngg-1). In this study, PBDEs, DP and EBFRs in sediment almost exhibited relatively lower levels as compared to those found in other studies, where the limited usage of HFRs in the middle and lower stream of the Yellow River was probably the major impact factor. EBFR was the predominate pollutant from SPM and sediments in most of the sampling sites, suggesting that EBFRs were widely used nowadays as substitute materials of 'old' FRs. The mean concentration values of DBDPE/BDE-209 in SPM and sediments were apparently higher than those of previous studies. Furthermore, it is interesting to reveal that herein almost all of the HFR concentrations were unrelated to the population and GDP, which might be attributed to the characteristics of 'elevated stream' of the Yellow River as well as the complex river systems in Henan province.

A visible-light responsive self-assembled perylenetetracarboxylic diimide (PDI)/reduced graphene oxide (rGO) composite film was obtained and showed excellent photocatalytic performance and efficient interfacial steam generation. The degree of π-π interactions between Perylenetetracarboxylic diimide supramolecular nanofibers (nano-PDI) and rGO regulated the energy band structure and redox potential of the composite film to produce h+ and O2− active species. The photothermal conversion of the composite film under visible light irradiation was realized, which was mainly because the above-bandgap electrons and holes of the upper nano-PDI relaxed to the edge of the band and converted the excess energy into heat. The unique energy band structure of rGO also promotes the effective photothermal conversion of the composite film. The composite film degraded 94.31 % (10 mg/L) of ciprofloxacin hydrochloride (CIP) under 0.5 sun visible light irradiation within 120 min. The corresponding interfacial steam generation efficiency via photothermal conversion of the composite film was 10.92 %. Furthermore, the composite film retained its excellent photothermal performance, when used to remove CIP from real water samples, including Yellow River water, Weihe River water, and tap water.

Harnessing renewable solar resources to drive water electrolyzer to attain hydrogen fuel is of paramount significance to a sustainable energy future. Nevertheless, the intermittent and instable drawbacks of sunlight greatly limit their practical applications. In this sense, incorporating an energy storage module in between the photovoltaic and electrolytic cells separately is an effective solution to cushion this issue. Herein, we devise a solar-driven self-powered electrocatalytic water splitting system, which employs photovoltaic cell to drive micro zinc-ion battery array to offer a stable voltage for continuously powering the seawater electrolyzer. Our design of miniature energy storage devices not only harvests high energy output but also reduces the bulky connection degrees of thus-integrated system. More impressively, the electrodes based on earth-abundant materials showcase multifunctionality, which is reflected in the good electrochemical performance of zinc-ion battery device, the impressive electrocatalytic activity toward overall water splitting, as well as the robustness to resist the corrosion within alkaline seawater. Our hybrid system would open up agitated ideas for the continuous acquisition of hydrogen fuel with low energy consumption, reasonable cost aspect and high environmental sustainability.

Mercury (Hg), six alkyl esters of p-hydroxybenzoic acid (parabens), and their metabolite, 4-hydroxybenzoic acid (PHBA), were simultaneously studied in sediments from the upper Huai River, Henan Province, China. There were higher concentrations of Hg in the surface sediments from the Huai River during the moderate precipitation season (MPS②) as compared to the minimal precipitation (MPS①) and high precipitation seasons (HPS), and as compared to core sediments. The Hg values in all sediments were above the background value. The Hg contents in the tributaries were much higher than those in the mainstream. The concentrations of ∑parabens in the core sediments ranged from 2.45 to 22.2 ng/g while the concentrations of PHBA ranged from 11.3 to 155 ng/g. Methylparaben (MeP) and propylparaben (PrP) were the most commonly detected parabens. Total organic carbon (TOC) and black carbon (BC) played important roles in the distribution of Hg in the surface sediments during the minimal precipitation and high precipitation seasons and affect the distribution of Hg and parabens in core sediments. Sand (>63 μm) was another factor affecting the distribution of Hg and parabens in core sediments. The concentrations of PHBA and Hg in core sediments were positively correlated. Temporal records of Hg and parabens in core sediments reflected local social changes. Hg content in the surface sediments during the MPS② was associated with relatively high ecological risks while parabens in the core sediments were associated with low level risks.

The adsorption behavior of perfluorooctane sulfonate (PFOS) on biochar produced from corn straw at varying pyrolytic temperatures ( i.e ., 250, 400, 550, and 700 °C, BC250–700, respectively) was investigated. High pyrolytic temperatures (>400 °C) resulted in the increase of some fine-pore structures, larger surface area (SA) and higher aromaticity of biochar. The adsorption kinetics of PFOS fitted well to a pseudo-second order model while the adsorption isotherms followed a Langmuir adsorption isotherm model ( R 2 > 0.949). The adsorption capacity increased with the pyrolytic temperature with the highest adsorption capacity ( i.e ., 169.30 mg/g) being obtained on BC 700. The adsorption of PFOS on the biochar samples was mainly governed by hydrophobic and electrostatic interactions. The hydrophobicity enhancement of biochar pyrolyzed at high temperatures is one of the important factors contributing to PFOS adsorption. The capacity of biochar for adsorbing PFOS decreased with the increase of solution pH. The adsorption of PFOS on the biochar samples is a spontaneous and endothermic process.

In order to investigate the distribution, transfer, and human health risks of polycyclic aromatic hydrocarbons (PAHs) in the soil-wheat systems, soil samples from 20 farmlands and corresponding wheat tissues were collected from selected regions of Henan Province in June 2013 and were analyzed to estimate the concentration of PAHs. The total concentrations of 15 PAHs (∑15 PAHs) in soils from Henan Province varied from 6.91 to 72.4 ng/g. Moreover, two-ring to three-ring PAHs (1.59-29.1 ng/g) were the major species in soils, occupying 56.2% of total PAHs. Principal component analysis (PCA)-multiple linear regression (MLR) revealed that fossil fuel burning dominated the input of PAHs in agricultural soils of Henan Province. The range of ∑15 PAHs concentrations in wheat tissues was 13.9-50.9 ng/g, which decreased along the root-straw-grain. Positive correlation among PAHs of soil and wheat tissues showed that PAHs in wheat mainly came from soil and then migrated along root-straw-grain. Moreover, PAHs were accumulated highest in root and lowest in grain. Two-ring to three-ring PAHs were easier to transfer from soil to wheat than five-ring to six-ring PAHs. Consumption of wheat grain created potential risk of cancer in Henan Province.

To investigate the contamination level, distribution, possible source, and human exposure risk of polycyclic aromatic hydrocarbons (PAHs) in the urban traffic environment, 15 PAHs were measured in 34 road dust samples (particle size < 25 μm) collected from three grades of roads and park paths in Xinxiang, China. ΣPAHs concentrations ranged from 311 to 21200 ng g−1, with a mean of 5890 ng g−1 and decreased in the following order: main roads (7650 ng g−1) > collector streets (7410 ng g−1) > bypasses (2970 ng g−1) > park paths (1570 ng g−1), indicating that significant positive correlation existed between PAH contamination and traffic density. PAHs in all samples were dominantly composed of 4-ring PAHs, accounting for 44.8% of the total. Pyrene, fluoranthene, and chrysene were the predominant individual components and accounted for 14.7% (1.2–19.2%), 12.9% (3.3–20.3%), and 11.0% (2.5–18.6%) of ΣPAHs, respectively. The specific isomer ratios indicated that traffic emission was the dominant source of PAHs in road dust. The incremental lifetime cancer risk values showed that cancer risk from exposure to road dust–borne PAHs was acceptable for local residents in Xinxiang.

The pollution characteristics of PM2.5 and correlation analysis with meteorological parameters in Xinxiang during the Shanghai Cooperation Organization Prime Ministers’ Meeting were investigated. During the whole meeting, nine PM2.5 samples were collected at a suburban site of Xinxiang, and the average concentration of PM2.5 was 122.28 μg m−3. NO3 −, NH4 +, SO4 2− accounted for 56.8% of the total water-soluble ions. In addition, with an exception of Cl−, all of water-soluble ions decreased during the meeting. Total concentrations of crustal elements ranged from 6.53 to 185.86 μg m−3, with an average concentration of 52.51 μg m−3, which accounted for 82.5% of total elements. The concentrations of organic carbon and elemental carbon were 7.71 and 1.52 μg m−3, respectively, lower than those before and after the meeting. It is indicated that during the meeting, limiting motor vehicles is to reduce exhaust emissions, delay heating is to reduce the fossil fuel combustion, and other measures are to reduce the concentration of PM2.5. The directly dispersing by mixing layer height increase and the indirectly reducing the formation of secondary aerosol by low relative humidity, and these are the only two key removing mechanisms of PM2.5 in Xinxiang during the meeting.

Twenty-four PM 2.5 samples were collected at a suburban site of Xinxiang during Chinese Spring Festival (SF) in 2015. 10 water-soluble ions, 19 trace elements and 8 fractions of carbonaceous species in PM 2.5 were analyzed. Potential sources of PM 2.5 were quantitatively apportioned using principal component analysis (PCA)-multivariate linear regressions (MLR). The threat of heavy metals in PM 2.5 was assessed using incremental lifetime cancer risk (ILCR). During the whole period, serious regional haze pollution persisted, the average concentration of PM 2.5 was 111 ± 54 μg m − 3 , with 95.8% and 79.2% of the daily samples exhibiting higher PM 2.5 concentrations than the national air quality standard I and II. Chemical species declined due to holiday effect with the exception of K, Fe, Mg, Al and K + , Cl − , which increased on Chinese New Year (CNY)'s Eve and Lantern Festival in 2015, indicating the injection of firework burning particles in certain short period. PM 2.5 mass closure showed that secondary inorganic species were the dominant fractions of PM 2.5 over the entire sampling (37.3%). 72-hour backward trajectory clusters indicated that most serious air pollution occurred when air masses transported from the Inner Mongolia, Shanxi and Zhengzhou. Health risk assessment revealed that noncancerous effects of heavy metals in PM 2.5 of Xinxiang were unlikely happened, while lifetime cancer risks of heavy metals obviously exceeded the threshold, which might have a cancer risk for residents in Xinxiang. This study provided detailed composition data and first comprehensive analysis of PM 2.5 during the Spring Festival period in Xinxiang.

The spatial and temporal distribution of polycyclic aromatic hydrocarbons (PAHs) in surface water from the upper reach of Huaihe River were investigated. The water and suspended particulate matter (SPM) samples from 16 sites were collected during three sampling cruises. The concentrations of ΣPAHs ranged from 79.94 to 421.07 ng/L with the average values of 140.37 ng/L in water and from 10.87 to 201.42 ng/L with the average values of 61.23 ng/L in SPM. In comparison to survey during March 2007, alleviated PAHs pollution was ascribed to the adjustment of energy structure. LMW PAHs (2- and 3-ring) were abundant in water and SPM samples with high detection frequencies. Seasonal variations of PAHs indicated that high concentrations of PAHs were recorded in the dry period (67.47–560.16 ng/L) and low levels of PAHs were detected in the flood period (27.87–458.47 ng/L) in water, while the high concentration of PAHs in SPM ranged from 4.14 to 342.32 ng/L in the dry period and low concentration from 2.42 to 129.23 ng/L in the level period. In situ water-SPM phase distribution revealed that PAHs tended to be transported with water phase in the studied area. Ratios of specific PAHs were calculated to evaluate the possible sources of PAHs contamination, which reflected PAHs in water and SPM derived from the mixed of pyrogenic and petroleum origins in different seasons.

The efficient enrichment and remediation of heavy metals from realistic wastewater and contaminated soil containing large excess of competitive ions remains a daunting challenge by far. In the present study, flower-like molybdenum disulfide decorated with iron oxide nanoparticles (MoS

Sludge properties are critical to the treatment performance and potentially correlate with nitrous oxide (N2O) generation during activated sludge processes. The hydrodynamic shear stress induced by aeration has a significant influence on sludge properties and is inevitable for wastewater treatment plants (WWTPs). In this study, the effects of aerobic induced hydrodynamic shear stress on sludge properties, N2O generation, and microbial community structure were investigated using three parallel sequencing batch reactors (SBRs) with identical dissolved oxygen (DO) concentrations. Results showed that with a shear stress increase from 1.5 × 10−2 N/m2 to 5.0 × 10−2 N/m2, the COD and NH4+-N removal rates were enhanced from 89.4% to 94.0% and from 93.9% to 98.0%, respectively, while the TN removal rate decreased from 66.0% to 56.5%. Settleability of the activated sludge flocs (ASFs) also increased with the enhancement of shear stress, due to variation in sludge properties including particle size, regularity, compactibility, and EPS (extracellular polymeric substances) composition. The increase in shear stress promoted oxygen diffusion within the ASFs and mitigated NO2−-N accumulation, leading to a decrease in the N2O–N conversion rate from (4.8 ± 0.3)% to (2.2 ± 0.6)% (based on TN removal). Microbial analysis results showed that the functional bacteria involved in the biological nitrogen removal was closely related with shear stress. The increase in shear stress favored the enrichment of nitrite oxidizing bacteria (NOB) while suppressed the accumulation of ammonia-oxidizing bacteria (AOB) and denitrifying bacteria (DNB).

In surface water from the middle and lower reaches of the Yellow River, total equivalent concentrations of 16 US EPA priority PAHs were calculated based on the measured concentrations. Ecological risk assessment approaches, including hazard quotient and overlapping areas of probability density curves, were performed to evaluate the combined ecological risks of PAHs to the aquatic organisms. The result from hazard quotient indicated that risk quotient of mollusks and zooplankton surpassed 0.1, suggesting potential risks. The potentially affected fractions of PAHs obtained from overlapping areas of probability density curve varied from 11.2% (dry season) to 5.1% (rainy season), which implied that PAHs had been posing pressures on the ecosystem. Health risk based on the incremental lifetime risk for PAHs was conducted to evaluate human cancer risk and noncarcinogenic hazard in the studied area. The results indicated that health risks mainly came from ingestion exposure pathway. The total cancer risks were in...

Based on the available toxicity data and the concentrations of polycyclic aromatic hydrocarbons (PAHs) in 16 surface sediments from upper reach of Huaihe River, overlapping areas of probability density curves and margin of safety (MOS10) were used to estimate the ecological risk of eight PAHs to aquatic organisms. The results indicated that the overlapping areas of Pyr, Nap, Fla, Ant, Phe, Ace, BaP, and Flu were 0.38, 0.29, 0.16, 0.11, 0.07, 0.03, 0.03, and 0.01, respectively. The risk of Pyr was the highest while that of Flu was the lowest. The overlapping area of ΣPAH8 was 0.72, higher than that of any individual PAHs due to their joint effect. The calculated MOS10 for Nap, Ace, Flu, Phe, Ant, Fla, Pyr, and BaP were 6.86, 5.42, 19.0, 2.72, 0.93, 0.75, 0.03, and 63.0, respectively. The probabilities of Nap, Ace, Flu, Phe, and BaP surpassing the 10th percentile value of the toxicity data were 0.07%, 0.30%, 0.05%, 1.97%, and 0.01%, respectively, suggesting minimal risk to aquatic organisms. However, the pr...

Seventeen PM2.5 samples were collected at Xinxiang during winter in 2014. Nine water-soluble ions, 19 trace elements and eight fractions of carbonaceous species in PM2.5 were analyzed. PM2.5 concentrations and elements species during different periods with different pollution situations were compared. The threat of heavy metals in PM2.5 was assessed using incremental lifetime cancer risk. During the whole period, serious regional haze pollution persisted, and the averaged concentration of PM2.5 was 168.5 μg m−3, with 88.2 % of the daily samples exhibiting higher PM2.5 concentrations than the national air quality standard II. The high NO3 −/SO4 2− ratio suggested that vehicular exhaust made an important contribution to atmospheric pollution. All of organic carbon and elemental carbon ratios in this study were above 2.0 for PM2.5, which might reflect the combined contributions from coal combustion, motor vehicle exhaust and biomass burning. Mean 96-h backward trajectory clusters indicated that more serious air pollution occurred when air masses transported from the Hebei, Shanxi and Zhengzhou. The concentrations of the water-soluble ions and trace elements on haze days were 2 and 1.8 times of those on clear days. The heavy metals in PM2.5 might not cause non-cancerous health issues by exposure through the human respiratory system. However, lifetime cancer risks of heavy metals obviously exceeded the threshold (10−6) and might have a cancer risk for residents in Xinxiang. This study provided detailed composition data and comprehensive analysis of PM2.5 during the serious haze pollution period and their potential impact on human health in Xinxiang.

The levels, potential sources and ecological risks of hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs) in Yellow River of Henan section, a typical agricultural area in China, were investigated. Surface water samples and suspended particulate matters (SPMs) were collected from 23 sites during two seasons. In wet season, the residues of ∑HCHs (α-HCH, β-HCH, γ-HCH and δ-HCH) and ∑DDTs (p,p'-DDT, o,p'-DDT, p,p'-DDE, p,p'-DDD) ranged from 41.7 to 290 and 4.42 to 269 ng/L in surface water, while those varied from 0.86 to 157 and 1.79 to 96.1 ng/g dw in SPM, respectively. Moreover, in surface water, the levels of HCHs and DDTs in wet season were much higher than those in dry season. The reverse was true for residues of HCHs and DDTs in SPM. Compared with the large rivers in other regions, the levels of HCHs and DDTs in the studied area ranked at high levels and the residual concentrations might cause adverse biological risk, especially for ∑HCHs during wet season. Distributions of HCHs and DDTs delineated that the input of tributaries made a significant effect on the residue of HCHs and DDTs in the mainstream. ∑HCHs in surface water were consist of 26.7 % α-HCH, 30.0 % β-HCH, 37.9 % γ-HCH and 5.45 % δ-HCH and those in SPM contained 5.16 % α-HCH, 22.1 % β-HCH, 60.5 % γ-HCH and 12.2 % δ-HCH on average. Combined with ratios of α-HCH/γ-HCH in surface water (0.70) and in SPM (0.09), the results strongly indicated that lindane was recently used or discharged in the studied area. The mean percentage of DDTs' isomers were 28.7 % p,p'-DDT, 29.8 % o,p'-DDT, 28.1 % p,p'-DDE and 13.4 % p,p'-DDD in surface water, while those were 12.5 % p,p'-DDT, 31.8 % o,p'-DDT, 30.5 % p,p'-DDE and 25.1 % p,p'-DDD in SPM. The ratios of (DDE + DDD)/∑DDTs and o,p'-DDT/p,p'-DDT revealed that the DDTs in the studied area mainly derived from long-term weathering of technical DDTs residue and the input of dicofol.

Based on the available toxicity data and the concentrations of DDTs and HCHs in surface water from the upper reaches of the Huaihe River, overlapping areas of probability density and margin of safety (MOS10) were used to estimate the risk levels of DDTs and HCHs to aquatic organisms. The overlapping areas of α-HCH, γ-HCH, p,p′-DDE, p,p′-DDD, and p,p′-DDT were found to be 9.3 × 10−5, 4.6 × 10−3, 4.3 × 10−2, 2.2 × 10−2, and 4.2 × 10−2, respectively. The risks from DDTs were higher than those from HCHs, the risk from α-HCH being the smallest. The MOS10 values of α-HCH, γ-HCH, p,p′-DDE, p,p′-DDD, and p,p′-DDT were 2.6 × 103, 97, 5.9, 15, and 8.6, respectively, i.e. greater than 1.0, indicating limited overlaps between the distributions of exposure concentrations and of toxicity data, and thus minimal ecological risk. Health risk calculations based on incremental lifetime risks for HCHs and DDTs were conducted to evaluate human cancer risk and non-carcinogenic hazard. The total cancer risks from organochlorine...

This study investigated the effects of exogenous N-acyl-homoserine lactone (AHL) signal molecules, N-hexanoyl-l-homoserine lactone (C6-HSL) and N-octanoyl-l-homoserine lactone (C8-HSL), on treatment performance, sludge properties and microbial community structures in activated sludge systems. Results showed that the nitrification and denitrification efficiencies were enhanced with the addition of signal molecules. The particle size, irregularity, and internal mass transfer resistance of activated sludge flocs (ASFs) increased, primarily because dosing AHLs led to a content increase and chemical composition variation of extracellular polymeric substances (EPS) in sludge. Microbial analysis indicated an increase in both the bacterial richness and diversity of the systems. The relative abundances of the key functional groups, including bacteria related to C and N removal and EPS production, varied correspondingly. This study presents an insight into the comprehensive understanding of the effects of AHL-based quorum sensing on activated sludge treatment process.

Immobilized cells (ICs) have been widely used to enhance the remediation of organic-contaminated soil (e.g., polycyclic aromatic hydrocarbons, PAHs). Once ICs are added to the heterogeneous soil, degradation hotspots are immediately formed near the carrier, leaving the remaining soil lack of degrading bacteria. Therefore, it remains unclear how ICs efficiently utilize PAHs in soil. In this study, the viability of Silica-IC (Cells@Sawdust@Silica) and the distribution of inoculated ICs and phenanthrene (Phe) in a slurry system (soil to water ratio 1:2) were investigated to explore the removal mechanism of PAHs by the ICs. Results showed that the Silica-IC maintained (i) good reproductive ability (displayed by the growth curve in soil and water phase), (ii) excellent stability, which was identified by the ratio of colony forming units in the soil phase to the water phase, the difference between the colony number and the DNA copies, and characteristics of the biomaterial observed by the FESEM, and (iii) high metabolic activity (the removal percentages of Phe in soil by the ICs were more than 95% after 48 h). Finally, the possible pathways for the ICs to efficiently utilize Phe in soil are proposed based on the distribution and correlation of Phe and ICs between the soil and water phase. The adsorption-degradation process was dominant, i.e., the enhanced degradation occurred between the ICs and carrier-adsorbed Phe. This study provided new insights on developing a bio-material for efficient bio-remediation of PAHs-contaminated soil.

The production and usage of antibiotics have been increasing rapidly with the improving quality of life and the rapid development of aquaculture, thus inducing the introduction of these antibiotics residues into the environment, increasing water pollution levels. Due to bioaccumulation, bacteriostatic activity, many of these threaten aquatic and terrestrial organisms. Here we prepared double-shelled ZnSnO3 hollow cubes for efficient photocatalytic degradation of antibiotic wastewater. The ZnSnO3, synthesized via co-precipitation, shows superior performance and stability compared to that prepared by hydrothermal and template-assisted methods. The prepared ZnSnO3 effectively photocatalyzed the degradation of not only ciprofloxacin and sulfamonomethoxine pharmaceutical wastewater, but also methylene blue, rhodamine B and methyl orange dye wastewater. The hollow structure facilitates the adsorption of dye molecules and provides a better platform for direct interaction between dye molecules and photocatalysts. Moreover, the antibacterial activity test for photocatalytic degradation effluent indicated that the biotoxicity of CIP toward Escherichia coli DH5a was eliminated after the ZnSnO3 photocatalysis under simulated irradiation. This study not only demonstrates an efficient photocatalyst, but also further indicates the effectiveness of photocatalytic technology in the treatment of antibiotic wastewater.

The efficient enrichment and remediation of heavy metals from realistic wastewater and contaminated soil containing large excess of competitive ions remains a daunting challenge by far. In the present study, flower-like molybdenum disulfide decorated with iron oxide nanoparticles (MoS2/Fe3O4) is designed via a two-step hydrothermal method and mainly applied in the removal of Hg(II) and Pb(II) ions in aqueous environment. Exhaustive morphological, chemical and magnetic characterizations verify the successful formation of magnetic MoS2/Fe3O4. Batch adsorption experiments show that the obtained MoS2/Fe3O4 nanohybrid enables efficient capture of Hg(II) and Pb(II) ions, accompanied by ease-of-separation from solution by simply applying a magnet. In this respect, high adsorption capacities (263.6 mg g−1 for Pb(II) and 428.9 mg g−1 for Hg(II)) can be gained under optimized conditions (pH = 5.0; 298 K; nanohybrid dosage: 0.8 g L−1 and the contact time: 180 min). In addition, the effects of different parameters such as initial Pb(II)/Hg(II) concentration (50–500 mg L−1), temperature (298, 308 and 318 K) and co-existing ions (Zn(II), Cu(II), Cd(II) and Mg(II)) were systematically probed. The favorable adsorption capacity, selectivity and recyclability mainly originates from the strong Hg2+/Pb2+···S2− bonding interactions. Practical application potential of magnetic MoS2/Fe3O4 nanohybrid in realistic lead-acid battery industry wastewater and Pb(II)-contaminated soil is further explored, achieving promising results with high Pb(II) removal efficiency of 99.63% for wastewater and 57.15% for soil. Simple preparation, easy separation and high adsorption capacity would foster thus-designed sulfide-based nanohybrid a promising adsorbent for heavy metal removal from wastewater and contaminated soil.