Search

In recent years, the co-contamination of heavy metals (HMs) and polycyclic aromatic hydrocarbons (PAHs) has attracted more and more attention, and finding efficient and coordinated removal method has been the hot focus. In this study, Fe/Mn-SBA15 bimetallic mesoporous silica adsorbent (Fe/Mn-SBA15) was prepared by hydrothermal method with the functional groups Fe and Mn simultaneously doped into the framework structure of SBA15. Fe/Mn-SBA15 was systematically characterized by XRD, TEM, and BET and used in removal of typical PAHs-pyrene and heavy metal-Cu (II) from aqueous solutions simultaneously. The single and binary adsorption behaviors were studied by kinetics, isotherm, pH, and ionic strength. The results showed that the functional groups of Fe and Mn were successfully loaded into the structure of SBA15 and the prepared adsorbent was still a typical mesoporous adsorbent. The adsorption of pyrene and Cu (II) onto Fe/Mn-SBA15 was fast and the adsorption equilibrium was achieved in 100 min. The Langmuir model fitted the adsorption isotherm better and the maximum adsorption capacities for pyrene and Cu (II) were 120 mg/g and 10.52 mg/g, respectively. The increase of ionic strength could enhance and decrease the adsorption capacity of pyrene and Cu (II), which may be attributed to salting-out effect and potassium competitive. With the increase of pH values, the negative charge on the surface of the adsorbent increased, resulting in the decrease and increase of adsorption capacity of pyrene and Cu (II) onto Fe/Mn-SBA15. In addition, Fe/Mn-SBA15 was found to have a synergistic effect on the adsorption of pyrene and Cu (II). This result is mainly due to the formation of hydration complex by pyrene-Cu (II) through cation-π interaction, which increases the adsorption capacity by occupying each other's adsorption sites of adsorbent. This study provides a new method for the synergistic removal of PAHs and HMs from aqueous solutions.

Self-supplied wells, an important water resource in remote and scattered regions, are commonly deteriorated by environmental pollution and human activity. In this study, 156 self-supplied well-water samples were collected from remote and scattered areas of Inner Mongolia (NMG), Heilongjiang (HLJ), and the suburbs of Beijing (BJ) in Northern China. Twenty-four heavy metals were identified by using the inductively coupled plasma-mass spectrometry (ICP-MS) and inductively coupled plasma-optical emission spectrometry (ICP-OES), and the associated human health risks were assessed by using standards of the US Environmental Protection Agency (US EPA). The concentrations of four heavy metals (As, Fe, Mn, and Tl) in HLJ, one heavy metal (Tl) in BJ, and ten heavy metals (Al, As, B, Cr, Fe, Mn, Mo, Se, Tl, and Zn) in NMG exceeded the limits set by China or the World Health Organization (WHO). The total carcinogenic risk (TCR) and total non-carcinogenic risk (THQ) exceeding set limits mainly occurred in NMG, compared to HLJ and BJ. Moreover, As accounted for 97.87% and 60.06% of the TCR in HLJ and BJ, respectively, while Cr accounted for 70.83% of the TCR in NMG. The TCR caused by Cd in all three areas had a negligible hazard (

Reactive oxygen species (ROS) are ubiquitous in the natural environment that are generated by chemical or biochemical processes. Plastic rainwater facilities, as an important part of modern rainwater systems, are inevitably deteriorated by ROS. As a consequence, microplastics will be released. However, information on how ROS affect the ageing characteristics of plastic rainwater facilities and the subsequent microplastic release behavior is still insufficient. To address this knowledge gap, Fenton reagents were used to simulate the reactive oxygen species (ROS) induced ageing process of three typical plastic rainwater components (rainwater pipe, made of polyvinyl chloride; modular storage tank, made of polypropylene; inspection well, made of high-density polyethylene) and the subsequent microplastic release behavior. After 6 days of Fenton ageing, an increase in sharpness, holes, and fractures on the rainwater facilities' surface was observed by scanning electron microscope (SEM). The functional group changes on the rainwater facilities' surface were analyzed by Fourier transform infrared spectrometer (FTIR) and two-dimensional correlation spectroscopy (2D-COS) and compared with the results of X-ray photoelectron spectroscopy (XPS). During the ageing process, oxygen-containing functional groups were generated and the carbon chains were broken, which promoted peeling and the release of microplastics. The amount of released microplastics (ranging from 158 to 6617 items/g facility) varied with the type of rainwater facilities, and the order was modular storage tankinspection wellrainwater pipe. The release amount increased with ageing time, and a significant linear relationship was observed (r

The aim of this study was to explore the influence and removal of household water purifiers (HWPs) on emerging contaminants in drinking water, and their distribution characteristics. The antibiotic resistance genes (ARGs), mobile genetic elements (MGEs), virulence factor genes (VFGs) and bacterial communities were profiled in the fouled filters, influents, and effluents from HWPs with five steps of filtration after 150 days operation, using metagenomics. The results showed that the diversity of dominant species in Poly Propylene 1 μm (PP1) and nanofiltration membrane (NM) was significantly higher than that in other filters. Post-activated carbon (AC) was used to detect low species richness or diversity, and the highest proportion of dominant species, which contributes to the greater microbial risk of HWPs effluents in drinking water. The number of dominant bacterial genera in the filters disinfected with chloramine was higher than that in the same group disinfected with chlorine. The bacterial species richness or diversity in water was reduced by the purification of HWPs because the filter elements effectively trapped a variety of microorganisms. The relative abundance of Antibiotic efflux in the effluents of chlorinated and chloraminated HWPs was 5.58 × 10

As one of the commonly used stormwater management measures, permeable pavement system (PPS) played a prominent role in controlling runoff pollution and alleviating urban waterlogging. In this study, new enhanced infiltration materials (construction waste brick, coal gangue, activated carbon, multi-walled carbon nanotube, multi-layer graphene) were applied in PPS and the control efficiency and mechanism of typical heavy metals (HMs, Mn

Particulate matter (PM), as an important carrier for carrying and transporting runoff pollutants, can significantly affect the behavior and removal efficiency of pollutants in bioretention facilities. In order to control the pollution caused by polycyclic aromatic hydrocarbons (PAHs) in bioretention facilities, the removal efficiency and migration characteristics of typical PAHs-naphthalene were systematically investigated under the influences of PM. The results showed that the removal efficiency of naphthalene was 74% ~ 97% in bioretention facilities under the influences of PM. With the higher naphthalene concentration, the lower rainfall return period, and the longer antecedent drying period, the removal efficiency of naphthalene in each media layer were higher. Furthermore, the PM in the runoff increased the naphthalene adsorption onto media in the first 10 cm depth, which showed more than 80% removal efficiency and lower mobility of naphthalene. The removal efficiency of naphthalene was significantly higher (90% ~ 97%), when the particle size and concentration of PM were 0 ~ 45 µm and 500 mg/L, respectively. This study investigated the important role of PM for naphthalene removal in bioretention facilities, and provided effective guidelines for runoff pollution control, design of stormwater facilities, and assessment risk of PAHs.

Intensive urbanization decreases the self-regulation of urban ecosystems, leading to accumulation of persistent pollutants such as trace metals and metalloids in urban environments. Road-deposited sediments (RDS) are important carriers of trace metals and metalloid contaminants that could contribute to urban runoff pollution. This study aims to investigate the concentration and speciation systemically and assess the risks of trace metals and metalloids from RDS comprehensively. Road-deposited sediments (RDS) were analyzed for As, Cd, Cr, Cu, Mn, Pb, and Zn, in terms of total concentrations, speciation, release, and risks at 23 sites across six land types (the rural-urban fringe, commercial, residential, industrial, traffic, and the natural areas) in Daxing District of Beijing, China, in April 2018. Risk factors evaluating different aspects included contamination levels and ecological risk, Igeo, and RI; source of metal (natural or anthropogenic), EF; bioavailability, RAC. Six particle sizes vs. metal concentrations were also analyzed for trace metals and metalloids from rural-urban fringe samples. Obvious variations were found for the concentrations of Cr, As, and Cd in rural-urban area, especially for Cr. Industrial sites exhibited highest average values for all trace metals and metalloids except for As and Cu. Cr, Cd, and Pb in particular posed more risk. Traffic area showed signs of contamination for Cu, Pb, and Zn. Commercial and residential areas presented low ecological risk. However, there were signs of As and Cu contaminations in both areas, and of Pb in the residential area as well. No research sites were contaminated by Mn, despite the high concentration values. Although high contamination levels of Cr were found in many sites, the risk level of Cr was low. Generally, RDS with smaller particle size (

The plant carbon source and sulfur were selected as the denitrification electron donors and filled in the internal water storage zone (IWSZ) of bioretention system to establish excellent mixotrophic denitrification system, which was beneficial to waste recycling and showed very high nitrate nitrogen removal efficiency (approximately 94%). The ammonia nitrogen, total nitrogen, and chemical oxygen demand removal efficiencies could reach 79.41%, 85.89%, and 74.07%, respectively. Mechanism study revealed the synergistic degradation effect was existed between acetic acid released from plant carbon source and the generated sulfate, which improved the S/CH

Polyvinyl alcohol and pumice synthetized guar gum-nanoscale zerovalent iron beads (PPG-nZVI beads) were synthesized, and their adsorption towards Pb2+, Cu2+, and Zn2+ ions was evaluated. The adsorption kinetics of metal ions was well fitted by the pseudo-second-order model. The adsorption rate decreased followed in the order of Cu2+ &gt, Pb2+ &gt, Zn2+, consistent with the reduction potential of the ions. The sorption isotherm was well fitted by Langmuir model. The maximum adsorption capacity decreased followed in the order of Pb2+ &gt, Cu2+ &gt, Zn2+, which suggested that the strength of covalent bonds between the metal ions and surface functional groups substituted to the beads is one of the major factors in the adsorption process. Adsorption increased with the increase of pH and the largest sorption occurred at pH 5.5, while ionic strength did not significantly influence the adsorption process. The application of PPG-nZVI beads as filling materials in the simulated stormwater infiltration facility shows good removal efficiency in treating the contaminated water containing Pb2+, Cu2+, Zn2+, Cr6+, and Cd2+ and the removal rate was more than 65% at least. The results indicated that the PPG-nZVI beads could be applied as promising sorbents for purification of heavy metal contaminated water.

In this study, to investigate the elimination of micropollutant from aqueous solutions by construction waste, waste red brick (WRB) with and without incorporated of iron species (goethite and hematite) were prepared by a simple method. The prepared materials were systematically characterized and batch experiments were conducted to study the elimination of typical micropollutant cimetidine from the water environment. Results showed that both two iron species could be successfully incorporated onto WRB and the main structure of WRB were maintained. The adsorption process of cimetidine onto bricks was fast due to the microstructure and useful adsorption sites on the surface of bricks. The Langmuir model fitted the experimental data better and the qmax of cimetidine increased about 24.4% and 39.6% for the incorporation of hematite and goethite, respectively. The pH values influenced the adsorption behavior greatly and the favorable pH value was around 6.0. The charge screening effect and competition adsorption may influence the adsorption behavior together. Due to the interaction between cimetidine and bricks, the outer-sphere complexation may be formed in the adsorption process. This study shows new methods for the elimination of the micropollutant from the water environment and offers useful guidelines for the reuse of construction waste.

The lead smelting industry has produced a large amount of heavy metal-containing solid wastes, and lead leaching from these wastes under acidic conditions poses a great threat to the environment. In this study, lead slag was effectively stabilized by a mechanochemical reaction through a co-grinding operation with quartz sand (SiO2) in a planetary ball mill. The synthetic precipitation leaching procedure (SPLP) was used to examine the stabilization efficiency of lead slag by ball milling, and the results demonstrated that the lead immobilization for smelting slag with initial lead leaching concentration of 1503 mg/L could reach 99.99% under the conditions of 1000 rpm and 35:1 charge ratio when the ball milling time was 2 h, which was under the permitted concentration of lead according to the Chinese standards for hazardous wastes (

Heavy metals such as Cu(II), if ubiquitous in the runoff, can have adverse effects on the environment and human health. Lime sand bricks, as low-cost adsorbents to be potentially applied in stormwater infiltration facilities, were systematically investigated for Cu(II) removal from water using batch and column experiments. In the batch experiment, the adsorption of Cu(II) to bricks reach an equilibrium within 7 h and the kinetic data fits well with the pseudo-second-order model. The sorption isotherm can be described by both the Freundlich and Langmuir model and the maximum adsorption capacity of the bricks is 7 &plusmn, 1 mg/g. In the column experiment, the best removal efficiency for Cu(II) was observed at a filler thickness of 20 cm, service time of 12 min with a Cu(II) concentration of 0.5 mg/L. The Cu(II) removal rate increases with the increasing bed depth and residence time. The inlet concentration and residence time had significant effects on the Cu(II) removal analyzed by the Box&ndash, Behnken design (BBD). The Adams-Bohart model was in good agreement with the experimental data in representing the breakthrough curve. Copper fractions in the bricks descend in the order of organic matter fraction &gt, Fe-Mn oxides fraction &gt, carbonates fraction &gt, residual fraction &gt, exchangeable fraction, indicating that the lime sand bricks after copper adsorption reduce the long-term ecotoxicity and bioavailability to the environment.

The concentration and distribution of Pb, Zn, Cu and Cr in the surface soil of three grassed swales located in the city of Beijing, Jiaxing and Shenzhen were studied in this paper. Evaluations on the risk of heavy metals were conducted based on the second level limit of soil environmental quality standard, using different indexes (i.e., single item, comprehensive items and potential ecological risk indexes). Results show that the concentration of Pb, Zn, Cu and Cr in all the soil samples is within the limit of second level of soil environmental quality standard of China, except the soil samples of the grassed swale from Shenzhen city. The result also shows that the concentration of the four kinds of heavy metals in the surface soil of grassed swales is linearly correlated with the depth of soil sampling points. In summary, ecological risk of heavy metals in the three grassed swales is slight.