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Spatial distributions and sources of PAHs in soil in chemical industry parks in the Yangtze River Delta, China Texto completo
2021
Jia, Tianqi | Guo, Wei | Xing, Ying | Lei, Rongrong | Wu, Xiaolin | Sun, Shurui | He, Yunchen | Liu, Wenbin
The Yangtze River Delta (YRD) is one of the fastest developing areas in eastern China and contains many chemical industry parks. The profiles and sources of polycyclic aromatic hydrocarbons (PAHs) in soil in chemical industry parks and surrounding areas in the YRD were investigated by analyzing soil samples (n = 64) were collected in the YRD and Rudong chemical park (RD), a typical chemical park in the Yangtze River Delta. The total concentrations of 19 PAHs in the YRD soil samples were 16.3–4694 ng g⁻¹ (mean 688 ng g⁻¹), and the total concentrations of PAHs in RD were 21.6–246 ng g⁻¹ (mean 75.4 ng g⁻¹). The PAHs in soil in YRD were dominated by four-ring and five-ring PAHs, and the PAHs in RD were dominated by two-ring and three-ring PAHs. It suggested that PAHs may have been supplied to soil in YRD predominantly through coal combustion and vehicle emissions, PAHs in the soil of RD may be due to the volatilization and leakage of chemical raw material. According to the different distribution characteristics of PAHs, the ratio (1.5) of (2 + 3) rings/4 rings was proposed to identify the chemical source of PAHs. The PAH isomer ratios and principal component analysis/multiple linear regression (PCA/MLRA) results indicated that PAHs concentrations in soil in the YRD and RD are mainly supplied by industrial and traffic emissions. Incremental lifetime cancer risks (ILCRs) indicated that PAHs in soil pose negligible cancer risks to children and adults, but much stronger risks to children than adults.
Mostrar más [+] Menos [-]Preparation of 2D nitrogen-doped magnetic Fe3C/C by in-situ self-assembled double-template method for enhanced removal of Cr(VI) Texto completo
2020
Su, Qiaohong | Su, Zhi | Xie, Wenyu | Tian, Chen | Su, Xintai | Lin, Zhang
Porous carbon, which can be functionalized, is considered as a potential carbon material. Herein, two-dimensional (2D) nitrogen-doped magnetic Fe₃C/C (NMC) was prepared by a simple carbonization method using potassium humate (HA-K) as raw material. Remarkably, two templates, g-C₃N₄ and KCl, were formed in situ during the carbonization process, which provide the necessary conditions for the formation of 2D NMC. The NMC was comprehensively studied by different characterization methods. The results show that NMC has a large surface area and mesoporous structure. The prepared NMC-0.50 was used to test the removal performance of Cr(VI). The effects of pH value, coexisting ions and time on Cr(VI) removal performance were investigated, and the adsorption kinetics, isotherm and thermodynamics were studied. The results showed that the adsorption isotherm model of NMC-50 accorded with the Langmuir model, and the maximum adsorption capacity was 423.73 mg g⁻¹. The reaction mechanism of Cr(VI) is adsorption and redox reaction. In addition, NMC-0.50 exhibit high selectivity, separability and regeneration performance. A convenient means for the synthesis of NMC was designed in this work, and demonstrate that NMC has practical value as an adsorbent.
Mostrar más [+] Menos [-]Geochemical exposure of heavy metals in environmental samples from the vicinity of old gas mining area in northern part of Sindh Pakistan. Adverse impact on children Texto completo
2019
Shaikh, Rafia | Kazi, Tasneem Gul | Afridi, Hassan Imran | Akhtar, Asma | Baig, Jameel Ahmed | Arain, Mohammad Balal
In early nineteen century, a gas field was operational in southern part of Sindh, Pakistan for power production. The plant was completely un-operational for last three decades, whereas all wastage and raw materials are still dumped there, which might be the source to contaminate the ground water. The most of the workers population still living in different villages nearby the gas field. In present study, evaluated the undesirable effects of the toxic metals (lead and cadmium) via consuming groundwater for drinking and other domestic purpose especially in children of ≤5.0 years. For comparative purpose groundwater of nonindustrial area (nonexposed) was also analysed and their impact on age matched children was carried out. Biological samples (scalp hair and blood) were collected from children of exposed and nonexposed areas. The Cd and Pb in scalp hair and blood samples were carried out by graphite furnace atomic absorption spectrometry. Whereas, Cd and Pb in groundwater obtained from both areas were determined prior to applied preconcentration method as reported in our previous works. The Cd and Pb contents in the groundwater of villages of exposed area were found in the range of 5.18–10.9 and 19.9–69.5 μg/L, respectively. Whereas, the groundwater of nonexposed area contains Cd and Pb in the range of 1.79–3.78 and 5.07–24.3 μg/L, respectively. It was observed that the concentrations of Cd and Pb in scalp hair and blood samples of children belongs to exposed area have ≥2.0 fold higher than the resulted data attained for age matched control children, indicating as the exposure biomarkers of toxic metals. The children belong to exposed area have poor health, anemic and low body mass index (<13 kg/m2). A significant positive correlations among Cd and Pb concentrations in biological samples of exposed subjects and groundwater was observed (p < 0.01).
Mostrar más [+] Menos [-]Application of sodium titanate nanofibers as constructed wetland fillers for efficient removal of heavy metal ions from wastewater Texto completo
2019
Zhao, Min | Wang, Sen | Wang, Hongsheng | Qin, Peirui | Yang, Dongjiang | Sun, Yuanyuan | Kong, Fanlong
Constructed wetlands are an environmentally friendly and economically efficient sewage treatment technology, with fillers playing an important role in treatment processes. However, traditional wetland fillers (e.g. zeolite) are known to be imperfect because of their low adsorption capacity. In this paper, the adsorbent sodium titanate nano fillers (T3-F) was synthesized as an alternative to traditional filler with sodium titanate nanofibers (T3) as the raw material, epoxy adhesive as the adhesive agent and NH₄HCO₃ as the pore-making agent. The properties of T3-F were characterized by powder X-ray diffraction (XRD), scanning electron microscope-energy dispersive X-ray spectroscopy (SEM-EDX), porosity. The effect of different parameters such as pH, co-existing ions, contact time, initial metal ion concentrations and temperature was investigated for heavy metal adsorption. The results showed that the adsorption of heavy metal by T3-F followed the pseudo-second-order kinetic and Langmuir isotherm models. The maximum adsorption capacities for Cu²⁺, Pb²⁺, Zn²⁺, Cd²⁺ were about 1.5–1.98 mmol/g, which were 4–5 times that of zeolite, the traditional commonly used filler. Moreover, T3-F could entrap toxic ions irreversibly and maintain structural stability in the adsorption process, which solved the issue of secondary pollution. In the presence of competing ions, the adsorption efficiency for Pb²⁺ was not reduced significantly. Adsorption was strongest at high pH. From the results and characterization, an adsorption mechanism was suggested. This study lays a foundation for the practical application of T3-F as a constructed wetland filler in the future.
Mostrar más [+] Menos [-]Widespread detection of a brominated flame retardant, hexabromocyclododecane, in expanded polystyrene marine debris and microplastics from South Korea and the Asia-Pacific coastal region Texto completo
2017
Jang, Mi | Shim, Won Joon | Han, Gi Myung | Rani, Manviri | Song, Young Kyoung | Hong, Sang Hee
The role of marine plastic debris and microplastics as a carrier of hazardous chemicals in the marine environment is an emerging issue. This study investigated expanded polystyrene (EPS, commonly known as styrofoam) debris, which is a common marine debris item worldwide, and its additive chemical, hexabromocyclododecane (HBCD). To obtain a better understanding of chemical dispersion via EPS pollution in the marine environment, intensive monitoring of HBCD levels in EPS debris and microplastics was conducted in South Korea, where EPS is the predominant marine debris originate mainly from fishing and aquaculture buoys. At the same time, EPS debris were collected from 12 other countries in the Asia-Pacific region, and HBCD concentrations were measured. HBCD was detected extensively in EPS buoy debris and EPS microplastics stranded along the Korean coasts, which might be related to the detection of a quantity of HBCD in non-flame-retardant EPS bead (raw material). The wide detection of the flame retardant in sea-floating buoys, and the recycling of high-HBCD-containing EPS waste inside large buoys highlight the need for proper guidelines for the production and use of EPS raw materials, and the recycling of EPS waste. HBCD was also abundantly detected in EPS debris collected from the Asia-Pacific coastal region, indicating that HBCD contamination via EPS debris is a common environmental issue worldwide. Suspected tsunami debris from Alaskan beaches indicated that EPS debris has the potential for long-range transport in the ocean, accompanying the movement of hazardous chemicals. The results of this study indicate that EPS debris can be a source of HBCD in marine environments and marine food web.
Mostrar más [+] Menos [-]Valorization of synthetic textile waste using CO2 as a raw material in the catalytic pyrolysis process Texto completo
2021
Kwon, Dohee | Yi, So-ra | Jung, Sungyup | Kwon, Eilhann E.
Since an invention of synthetic fibers (textiles), our life quality has been improved. However, the cumulative production and disposal of them have perceived as significant since they are not biodegradable and hard to be upcycled/recycled. From washing textiles, microplastics are released into the environment, which are regarded as emerging contaminants. As a means for source reduction of microplastics, this study proposed a rapid disposal platform for waste textiles (WTs), converting them into value-added products. To this end, catalytic pyrolysis of WT was studied. To offer more environmentally sound process, CO₂ was used as a raw material for WT pyrolysis. Thermal cracking of WT led to the production of syngas and CH₄ under the CO₂ environment. CO₂ resulted in additional CO production via gas phase reaction with volatile compounds evolved from pyrolysis of WT. To expedite the reaction kinetics for syngas formation, catalytic pyrolysis was done over Co-based catalyst. Comparing to non-catalytic pyrolysis, CO₂-assisted catalytic pyrolysis had 3- and 8-times higher production of H₂ and CO, respectively. This process also suppressed catalyst deactivation, converting more than 80 wt% of WT into syngas and CH₄. The more generation of CO from the use of CO₂ as a raw material offers an effective means to minimize the formations of harmful chemical species, such as benzene derivatives and polycyclic aromatic hydrocarbons.
Mostrar más [+] Menos [-]Biomaterial functionalized cerium nanocomposite for removal of fluoride using central composite design optimization study Texto completo
2020
Nehra, Sapna | Raghav, Sapna | Kumar, Dinesh
Excess fluoride concentration in drinking water is a global issue, as this has an adverse effect on human health. Several adsorbents have been synthesized from natural raw material to remove fluoride from water. Reported adsorbents have some problems with the leaching of metal ions, fewer adsorption sites, and low adsorption capacity. Therefore, to address this, an effective biomaterial derived from the Luffa cylindrica (LC), containing many active sites, was integrated with a nano form of cerium oxide to form a robust, biocompatible, highly porous, and reusable LC–Ce adsorbent. This synthesized biosorbent offers better interaction between the active sites of LC–Ce and fluoride, resulting in higher adsorption capacity. Several factors, influence the adsorption process, were studied by a central composite design (CCD) model of statistical analysis. Langmuir’s and Freundlich’s models well describe the adsorption and kinetics governed by the pseudo–second–order model. The maximum monolayer adsorption capacity was found to be 212 and 52.63 mg/g for LC–Ce and LC, respectively determined by the Langmuir model. Detailed XPS and FTIR analyses revealed the underlying mechanism of fluoride adsorption via ion-exchange, electrostatic interaction, H–bonding, and ion-pair formation. All the results indicate that LC–Ce could serve as a suitable adsorbent for efficient fluoride removal (80–85%).
Mostrar más [+] Menos [-]Nonylphenol exposure affects mouse oocyte quality by inducing spindle defects and mitochondria dysfunction Texto completo
2020
Xu, Yi | Sun, Ming-Hong | Xu, Yao | Ju, Jia-Qian | Pan, Meng-Hao | Pan, Zhen-Nan | Li, Xiao-Han | Sun, Shao-Chen
Nonylphenol (NP) is a chemical raw material and intermediate which is mainly used in the production of surfactants, lubricating oil additives and pesticide emulsifiers. NP is reported to be toxic on the immune system, nervous system and reproductive system due to its binding to estrogen receptors. However, the toxicity of NP on mammalian oocyte quality remains unclear. In present study, we explored the effects of NP exposure on mouse oocyte maturation. Our results showed that 4 weeks of NP exposure increased the number of atresia follicles and decreased oocyte developmental competence. Transcriptomic analysis indicated that NP exposure altered the expression of more than 800 genes in oocytes, including multiple biological pathways. Subcellular structure examination indicated that NP exposure disrupted meiotic spindle organization and caused chromosome misalignment. Moreover, aberrant mitochondrial distribution and decreased membrane potential were also observed, indicating that NP exposure caused mitochondria dysfunction. Further analysis showed that NP exposure resulted in the accumulation of reactive oxygen species (ROS), which causes oxidative stress; and the NP-exposed oocytes showed positive Annexin-V signal, indicating the occurrence of early apoptosis. In summary, our results indicated that NP exposure reduced oocyte quality by affecting cytoskeletal dynamics and mitochondrial function, which further induced oxidative stress and apoptosis in mice.
Mostrar más [+] Menos [-]A two-year field study of using a new material for remediation of cadmium contaminated paddy soil Texto completo
2020
Zhao, Hanghang | Huang, Xunrong | Liu, Fuhao | Hu, Xiongfei | Zhao, Xin | Wang, Lu | Gao, Pengcheng | Ji, Puhui
Cadmium (Cd) as a highly toxic heavy metal can cause seriously harmful to human health. Rice consumption is a major source of Cd intake by Chinese. Reduce the Cd accumulation by rice is the key for reducing Cd hazard. Therefore, fly ash (FA) was used as raw material in this study, after the process of simplifying hydrothermal synthesis the zeolite (ZE), which was named as low-temperature-alkali roasting, a new intermediate materials (IP) was got. And the three mentioned materials (FA, IP and ZE) were used for a two-year field experiment. The study demonstrated that, application of IP and ZE could promote rice growth, as well as increase soil pH, and improve available Si content. The rice production increased by 36.1% and 29.8% in 2017 by IP and ZE applied, enhanced 35.9% and 31.7% in 2018, respectively. Meanwhile, the bio-available Cd decreased by 26.9% and 26% in 2017, reduced by 22.9% and 28% in 2018, respectively. Generally, the passivators could promote the conversion of acid-exchangeable fraction Cd to reducible fraction Cd. It can be conclude that, IP and ZE have good remediation effect on contaminated soil, and alleviated effects on Cd accumulation by rice, even though no significant difference was detected between IP and ZE. The synthesis process of IP of is simpler than ZE. The impact of IP on contaminated soil needs further exploration.
Mostrar más [+] Menos [-]Determination of bisphenol A and bisphenol S by a covalent organic framework electrochemical sensor Texto completo
2020
Pang, Yue-Hong | Huang, Yu-Ying | Wang, Li | Shen, Xiao-Fang | Wang, Yi Ying
Bisphenol A (BPA) is a widely produced chemical that is mainly used as raw material for manufacturing plastic products. It is an endocrine disruptor and causes irreversible damage to the human body. Bisphenol S (BPS), an alternative to BPA, has low dose effects on toxicology and genotoxicity. Herein, we constructed a highly porous crystalline covalent organic framework (COF, CTpPa-2)-modified glassy carbon electrode (GCE) for the electrochemical sensing of BPA and BPS. The electrochemical properties of the CTpPa-2/GCE were characterized using galvanostatic charge-discharge, cyclic voltammetry and differential pulse voltammetry. The CTpPa-2/GCE exhibited remarkable electrocatalytic activity, and the electrochemical responses for BPA and BPS were found to be linear in the concentration ranges of 0.1–50 μM and 0.5–50 μM with detection limits of 0.02 μM and 0.09 μM (S/N = 3), respectively. Moreover, the fabricated sensor was utilized to determine BPA and BPS in bottle samples with recoveries of 87.0%–92.2% and migration rates of 13.2%–28.0%.
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