The pollution of heavy metals and organic compounds has received increased attention in recent years. In the current study, a novel biochar-based iron oxide composite (FeYBC) was successfully ...synthesized using pomelo peel and ferric chloride solution through one-step process at moderate temperature. Results clearly demonstrate that FeYBC exhibited more efficient removal of Cr(VI) and/or phenol compared with the pristine biochar, and the maximum adsorption amounts of Cr(VI) and phenol by FeYBC could reach 24.37 and 39.32 mg g−1, respectively. A series of characterization data suggests that several iron oxides such as Fe2O3, Fe0, FeOOH and Fe3O4 were formed on the FeYBC surface as well as oxygen-containing groups. Thermodynamics study indicates that Cr(VI) and phenol adsorption by FeYBC were endothermic and exothermic processes, respectively. Langmuir adsorption isotherm and pseudo-second order models could better explain the Cr(VI) and phenol adsorption behaviors over FeYBC. The Cr(VI) adsorption might be primarily achieved through the ion exchange and surface complexation and reduction, whereas the π–π interaction and electron donor–acceptor complex mainly contributed to phenol adsorption. The findings indicate that the biochar-based iron oxide composites material was an efficient adsorbent for the remediation of industrial effluents containing Cr(VI) and phenol.
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•A novel biochar-based iron oxide composite (FeYBC) was firstly synthesized.•FeYBC exhibited more efficient Cr(VI) and phenol removal than pristine biochar.•Langmuir and pseudo second order models well explain Cr(VI) and phenol adsorption.•Cr(VI) and phenol adsorption were endothermic and exothermic nature, respectively.•The possible removal mechanism of both Cr(VI) and phenol adsorption was proposed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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•FeS2@SiO2 microspheres were firstly employed to activate persulfate (PS).•UV induced a significant improvement in the degradation of bisphenol A (BPA).•A synergistic effect between ...photochemical and catalytic processes was achieved.•SO4− radicals prevailed over HO in the FeS2@SiO2 microspheres/PS/UV system.•A possible reaction pathway and mechanism of BPA degradation was proposed.
In this study, FeS2@SiO2 microspheres were firstly employed as a heterogeneous catalyst to activate persulfate (PS) for the degradation of bisphenol A (BPA) from aqueous solutions. The most relevant findings revealed that UV irradiation induced a significant improvement in the degradation of BPA by the FeS2@SiO2 microspheres/PS system. Nearly 100% of BPA degradation by the FeS2@SiO2 microspheres/PS/UV system was achieved within 120 min at reaction conditions of 1 mM PS, 0.066 mM BPA, 1.0 g/L FeS2@SiO2 microspheres and pH 3.0. A high performance on the degradation of BPA might be attributable to a synergistic effect between the PS/UV and the FeS2@SiO2 microspheres/PS catalytic processes. It was found that the BPA degradation could be inhibited by the coexisting anions like Cl−, HCO3− and PO43− to different extents at much higher concentrations, whereas NO3− had a negligible effect. Organic acids such as ethylene diamine tetra-acetic acid (EDTA) and oxalic acid (OA) would lead to an enhancement with a lower dosage, whereas a significantly negative effect was observed at much higher dosages. Radical scavenging tests revealed that the SO4− radicals prevailed over HO. A total of seven intermediates during the degradation of BPA were identified by GC/MS, and a possible reaction pathway and mechanism of BPA degradation by the FeS2@SiO2 microspheres/PS/UV system was proposed. This study demonstrated a simple water treatment method involving the use of low cost natural iron minerals for organic pollutants removal.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Exposure to polycyclic aromatic hydrocarbons (PAHs) during pregnancy may pose adverse health risk to both the mothers and babies. In the present study, 188 pregnant women of different trimesters were ...recruited in Guangzhou, south China, and nine hydroxyl PAHs (OH-PAHs) and a biomarker of DNA oxidative damage, 8-hydroxy-2′-deoxyguanosine (8-OHdG), were determined in their urine samples. All OH-PAHs except for 4-hydroxyphenanthrene and 6-hydroxychrysene were found in > 90% samples, with total concentration in the range of 0.52 to 42.9 μg/g creatinine. In general, concentration levels of OH-PAHs in pregnant women were lower than those in general population in the same research area but with higher levels in working women than in housewives. The mean daily intakes of PAHs from dietary estimated by urinary OH-PAHs were 0.021, 0.004, 0.047, and 0.030 μg/kg_bw/day for naphthalene, fluorene, phenanthrene, and pyrene, respectively, which were much lower than the reference doses (20, 30, and 40 μg/kg_bw/day for naphthalene, pyrene, and fluorene, respectively) derived from chronic oral exposure data by the United States Environmental Protection Agency. The low exposure levels of PAHs may be attributed to the traditional dietary taboo of Chinese pregnant women, which is to minimize the consumption of “toxic” food. The concentrations of 8-OHdG (4.67–49.4 μg/g creatinine) were significantly positively correlated with concentrations of several OH-PAHs, such as metabolites of naphthalene, fluorene, and phenanthrene (
r
= 0.3–0.6). In addition, the concentrations of 8-OHdG were higher in working women than in housewives when exposed to the same levels of PAHs, partly indicating the possible relation between work-related pressure for working women and the oxidative stress.
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•A high performance of Cr(VI) removal was obtained in AMD-nZVI/PDS process.•Transformation products of Cr(VI), Cd(II) and ATZ were identified.•SO4− contributed to nearly 84% of the ...overall ATZ degradation.•The possible pathways of ATZ degradation were proposed.•A reaction mechanism for the removals of Cr(VI), Cd(II) and ATZ was proposed.
Nowadays, inorganic and organic pollutants always coexist in the environment, thus an economic and efficient treatment is urgently required. In this paper, a novel nanoscale zero valent iron (AMD-nZVI) produced from the reaction of acid mine drainage (AMD) with NaBH4 was combined with peroxydisulfate (PDS) for the simultaneous removals of Cr(VI), Cd(II) and atrazine (ATZ) in water. Results demonstrate that the reactivity of AMD-nZVI/PDS process toward Cr(VI) removal was superior to that of AMD-nZVI/HCl or AMD-nZVI/H2O2 process. The coexisting species inculding PO43-, HCO3−, NO3 and humic acid exhibited obvious suppression on the Cr(VI) removal. The simultaneous removal efficiencies of Cr(VI), Cd(II) and ATZ by AMD-nZVI/PDS process were high up to 90% within 40 min. Most of Cr(VI) species were converted to Cr2O3 and Cr(OH)3, whereas both Cd(OH)2 and CdO were main Cd(II) species. The radical quenching tests affirmed that SO4− was the primary radical species for ATZ degradation. A total of five intermediate products of ATZ were sucessfully identified, and the degradation of ATZ was achieved through dealkylation, dechlorinatione and hydroxylation processes. A possible reaction mechanism involving in Cr(VI) reduction, Cd(II) precipitation and ATZ Fenton-like oxidation by AMD-nZVI/PDS process therefore was proposed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Nowadays, environmental problems caused by residual antibiotics are getting increasing attention. In the present work, peroxymonosulfate (PMS) was firstly employed for the enhanced degradation of ...norfloxacin (NOF) by a calcium-based Ag3PO4 composite (Ca-Ag3PO4) under visible light irradiation. Experiment results show that NOF removal in Ca-Ag3PO4/PMS/visible light process was higher than the sum of that in Ca-Ag3PO4/visible light and Ca-Ag3PO4/PMS processes. This significant enhancement of NOF removal was mainly due to a synergistic effect between photocatalysis of Ca-Ag3PO4/visible light process and Fenton reaction of Ca-Ag3PO4/PMS process. The inhibitory effects of water quality components on NOF removal followed: Humic acid (HA) > PO43-> HCO3−> NO3−> Cl−. NOF and co-existing heavy metals (ie., Cr(VI) and Ni(II)) or organic compounds like tetracycline (TC) could be simultaneously removed. Both PMS and H2O2 exhibit positive effects on the removal of NOF, but PMS could more effectively improve NOF removal compared with H2O2. An excellent PMS decomposition had been achieved in Ca-Ag3PO4/PMS/visible light process. HO•, SO4•− and 1O2 all took part in NOF degradation by Ca-Ag3PO4/PMS/visible light process, but both HO• and SO4•− might be primary species for NOF degradation. A plausible degradation pathway of NOF in Ca-Ag3PO4/PMS/visible light process was thereby proposed to proceed through ring-opening cracking hydroxylation and elimination reactions reactions. The enhanced reaction mechanism for the degradation of NOF in Ca-Ag3PO4/PMS/visible light process was also proposed.
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•An efficient NOF removal was obtained in Ca-Ag3PO4/PMS/visible light process.•PMS could more effectively improve NOF removal compared with H2O2.•Both HO.• and SO4•− might be primary species responsible for NOF degradation.•NOF degradation was achieved via hydroxylation and elimination reactions.•The enhanced reaction mechanism of NOF degradation was proposed.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In this article, a carbon cloth composite electrode modified with gold nanoparticles (AuNPs) was prepared by a facile in situ electrodeposition method and applied to the detection of mercury ions in ...water. With the optimized electrochemical detection conditions and methods, the limit of detection (LOD) was 0.6 μg L
with the linearity ranging from 2 to 200 μg L
by the SWSV detection method, and the electrode showed good repeatability after many cycles. Based on this detection method, a continuous flow electrochemical detection system was constructed and applied to the detection of Hg ions in environmental water samples. The standard addition experimental results of two real water samples with an addition level of 10 and 50 μg L
showed that the recoveries were between 92.4% and 108.9% with RSDs from 2.01% to 3.22%. These results showed the same performance as that of the ZAAS mercury detection method (recovery: 94-102.4%, RSD 2.09-5.4%). Compared with other electrode materials, a shorter detection time, a wider linear range and high stability with a similar LOD can be achieved by a continuous flow detection method by using the composite electrode. The established continuous flow electrochemical detection system would have promising application in online and real-time detection of heavy metals in environmental water.
Throughout history, rivers and lakes have wielded a profound influence on the dynamics of urban transportation expansion. To illustrate this phenomenon, we turn to the century-long evolution of the ...road network in Wuhan, China, as a case study. The study aims to explore the relationship framework between water bodies and urban transportation, characterized by the sequence of "strong connection" to "weakened connection", then to "mutual restriction", and ultimately to "mutual benefit". Additionally, the analysis of the impact mechanisms of rivers and lakes on urban transportation at different stages of development is also a key research objective. To facilitate our exploration, we select the road networks in Wuhan from four years of 1922, 1969, 1995, and 2023 as the primary research subjects. By establishing water buffers, we scrutinize the evolving characteristics of riverside and lakeside transportation amidst the city's expansion. Based on the modified shortest path model, we introduce the innovative concepts of "Detour Index" and "Weighted Detour Index" to assess the road accessibility of each node in the city based on its inherent environmental conditions. This allows for the effective analysis of the potential impact of water bodies as "obstacles" on the road network at different stages of urban development. The study found that in the areas adjacent to the rivers and lakes in Wuhan, there is insufficient road accessibility based on their inherent environmental conditions. Particularly, some areas along the rivers may become "terminals" in the urban road network. Furthermore, during the process of urban expansion, the correlation between the urban road network and rivers continues to weaken, while the correlation with lakes continues to strengthen. These conclusions can provide valuable insights for the planning of urban roads near water bodies.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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•Persulfate (PS) significantly enhanced AMX removal by TiO2@nZVI/UV process.•The decomposition rate of PS in TiO2@nZVI/PS/UV process was the highest.•Both HO• and SO4•− were the ...dominant radicals in TiO2@nZVI/PS/UV process.•AMX was effectively degraded through hydroxylation and deamination reactions.•A mechanism for the simultaneous removals of AMX and NOF was proposed.
In recent years, a serious threat of antibiotic residues in aquatic environments to human health and ecological security has become increasingly widespread attention. In this study, this is the first report on an alternative strategy on enhanced degradation of amoxicillin (AMX) and norfloxacin (NOF) by TiO2@nZVI/persulfate (PS) process under UV irradiation. Results revealed that a signficantly synergistic effect on AMX degradation had been achieved in TiO2@nZVI/PS/UV process due to the photocatalysis and Fenton-like reactions. NO3–, HCO3–, PO43- and humic acid exhibited inhibitory effects on AMX degradation, whereas Cl- was negligible on that. The degradation of AMX decreased as the addition of Cr(VI) concentrations increased, whereas the correspond values were enhanced when a low Cu(II) concentration was introduced. TiO2@nZVI/PS/UV process was the most efficient for activating PS decomposition. HO•, SO4•− and 1O2 were all generated in TiO2@nZVI/PS/UV process, but HO• and SO4•− were the dominant radical species for AMX degradation. The AMX intermediates products identified by LC-MS system confirmed AMX was effectively degraded through hydroxylation and deamination reactions. A better performance on the simultaneous removals of AMX and NOF by TiO2@nZVI/PS/UV process could be achieved at lower concentration conditions, and the simultaneous reaction mechanism was thereby proposed base on expriment results.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•A GC–MS method for 10 bisphenols(BPs) and 12 natural estrogens(NEs) were developed.•Ten BPs and twelve NEs in eight drinking water treatment plants (DWTPs) were studied.•The far-less studied NEs ...were found both in the source and finished drinking water.•Residual BPs and NEs in drinking water may pose estrogenic effects on human.
Bisphenol analogues (BPs) and natural estrogens (NEs) as two important groups of endocrine-disrupting compounds (EDCs) in drinking water treatment plants (DWTPs) have been hardly investigated except bisphenol A (BPA) and three major NEs including estrone (E1), 17β-estradiol (E2) and estriol (E3). In this study, a GC–MS analytical method was firstly established and validated for trace simultaneous determination of ten BPs and twelve NEs in drinking water, which included BPA, bisphenol B (BPB), bisphenol C (BPC), bisphenol E (BPE), bsiphenol F (BPF), bsiphenol P (BPP), bisphenol S (BPS), bisphenol Z (BPZ), bisphenol AF (BPAF), bisphenol AP (BPAP), E1, E2, E3, 17α-estradiol (17α-E2), 2-hydroestrone (2OHE1), 16hydroxyestrone (16α-OHE1), 4-hydroestrone (4OHE1), 2-hydroxyesstradiol (2OHE2), 4-hydroxyestradiol (4OHE2), 17-epiestriol (17epiE3), 16-epiestriol (16epiE3) and 16keto-estraiol (16ketoE2). This investigation showed that eighteen out of twenty-two targeted compounds were detected in drinking source waters of eight DWTPs with concentrations ranging from not detected to 142.8 ng/L. Although the conventional treatment process of DWTP could efficiently remove both BPs and NEs with respective removal efficiencies of 74.1%-90.9% and 74.5%-100%, BPA, BPS, BPE, BPZ, E1, 2OHE1, and 2OHE2 were found in the finished drinking waters. Chlorination could remove part of BPs and NEs, but the efficiency varied greatly with DWTP and the reason was unknown. In the finished drinking waters of eight DWTPs, the highest chemically calculated estrogen equivalence (EEQ) derived from BPs and NEs was up to 6.11 ngE2/L, which was over 22 times that could do harm to zebrafish, indicating a potential risk to human health. Given the fact that many chlorination products of BPs and NEs likely have higher estrogenic activities, the estrogenic effect of BPs and NEs in finished drinking water should be accurately examined urgently with the inclusion of BPs, NEs as well as their main chlorinated by-products. This study shed new light on the occurrence, removal, and potential estrogenic effects of BPs and NEs in DWTPs.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A series of environmental protective policies have been taken recently in the Pearl River Estuary (PRE) to alleviate water pollution; however, their influence on the reduction of heavy metals in ...estuarine water has not been known. This study selected Guangzhou as a representative city in the PRE and collected estuarine water monthly from 2008 to 2017 to track the variation of As, Hg, Pb, Cd, Cu, Zn, and Se. During the last decade, the high time-resolved record showed that the concentration of Hg, Pb, Cd, Cu, and Zn in estuarine water reduced by 39.5%, 91.0%, 86.2%, 74.6%, and 97.3%, respectively. However, the concentration of As kept in a stable range (1.89–2.69 μg L
−1
) and Se (0.17–0.65 μg L
−1
) increased slightly. The principal component analysis (PCA) and absolute principal component scores-multiple linear regression (APCS-MLR) results suggested that the upstream industrial effluents were major sources for Hg (45.5–92.7%), Pb (47.3–100%), Cd (42.0–90.6%), Cu (85.5–100%), and Zn (100%) and the geogenic source was major origin for As (84.6–98.3%) and Se (0–67.5%). The risk quotient of Hg, Pb, Cd, Cu, and Zn to aquatic organisms largely decreased from 0.03, 0.59, 0.03, 2.06, and 0.26 in 2008 to 0.02, 0.05, 0.006, 0.52, and 0.007 in 2017, respectively. The effective control of heavy metal pollution in the study area can be primarily due to the relocation of hundreds of polluting factories during the last decade.
