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Mechanism insight of acetaminophen degradation by the UV/chlorine process: kinetics, intermediates, and toxicity assessment
2019
Li, Jiaqi | Zhou, Siqi | Li, Miao | Du, Erdeng | Liu, Xiang
The removal of acetaminophen (AAP) in aqueous solution by the UV/chlorine process was evaluated. The effect of chlorine dose, the initial AAP concentration, pH value, and UV intensity on the reaction were also investigated. The degradation mechanism and the ecological risk were further discussed. The results indicated that AAP degradation fitted pseudo-first-order kinetics. Compared with UV alone or dark chlorination, the combination of UV and chlorine significantly accelerated the degradation process. The AAP degradation was positively affected by chlorine dose and UV intensity, while negatively affected by the initial AAP concentration and ammonia nitrogen concentration during the UV/chlorine process. The frontier orbital theory analysis shows that the C5 position in the benzene ring of AAP is likely to be the first site attacked by HO• and Cl• radical to form the products. Twelve intermediates were identified by Q-TOF and GC-MS. The possible degradation pathways were also proposed. Luminescent bacteria experiment and ECOSAR prediction both revealed that acute toxicity of AAP degradation could only be partially reduced. Ecological risks during the UV/chlorine process need to be further evaluated.
Show more [+] Less [-]Nitrate trends in groundwater of the Campania region (southern Italy)
2019
Ducci, Daniela | Della Morte, Renata | Mottola, Adolfo | Onorati, Giuseppe | Pugliano, Giovanni
The Environmental Protection Agency of the Campania region in Italy (ARPAC) manages a groundwater quality monitoring network. For almost all the polluted waters, the key parameter driving the classification is the concentration of nitrate; hence, the Campania region, in coherence with the EU regulations, outlined the vulnerable areas and undertook remediation policies. The best groundwater quality is recorded for carbonate aquifers of the Apennine chain; on the contrary, the Tyrrhenian coastal plains are affected by severe contamination, with a locally very contaminated groundwater of the shallow and also the deeper aquifers. The study is especially focused on a large coastal plain of Campania region, where nitrate concentration sometimes exceeds 200 mg/L. The study, based on almost 200 sampling points for the whole region during the period 2003–2015 (approx two samples per year), verified the effectiveness of the groundwater monitoring network, the present distribution of nitrate in groundwater, and the evolution of nitrate trends at different scales: regional, groundwater body, and single well, using spatial and time series statistical approaches. Significant variations in contamination evolution within the study area have been observed and the correlation with land use has been highlighted.
Show more [+] Less [-]Taking the bait: species taking oral rabies vaccine baits intended for raccoons
2019
Haley, Betsy S. | Berentsen, Are R. | Engeman, Richard M.
Raccoon rabies in eastern USA is managed by strategically distributing oral rabies vaccine (ORV) baits. The attractiveness, palativity, density, and non-target species bait take affect ORV effectiveness. We examined raccoon and non-target species differences in investigating/removing fish-meal polymer and coated sachet baits applied to simulate two aerial bait distribution densities. Bait densities of 150 baits/km² and 75 baits/km² were evaluated, respectively, in zones expected to have high and low raccoon densities. Three primary non-target species visited baits: coyotes, white-tailed deer, and feral swine. The proportion of bait stations visited by raccoons during 1 week observation periods ranged from 50 to 70%, exceeding non-target species visitation. Raccoon take rates for visited baits averaged from 59 to 100%. Raccoon visitation was similar for both bait densities, indicating a proportionally greater quantity of baits were taken in the higher bait density zone. Coyote visitation rates ranged from 16 to 26%, with take rates for visited baits between 46 and 100%. Coyotes were expected to take baits intended for raccoons, because similar baits are applied to vaccinate coyotes. Deer regularly investigated but rarely took baits. Feral swine were in low abundance in the high bait density zone (higher human density) and visited ≤ 1% of baits there but visited baits at frequencies similar to coyotes and deer in the low-density zone and were likely to take encountered baits (63–100%). Non-target bait consumption could be a concern in some circumstances for achieving sufficient raccoon sero-conversion rates.
Show more [+] Less [-]Ecotoxicological effects and accumulation of ciprofloxacin in Eichhornia crassipes under hydroponic conditions
2019
Yan, Yan | Xu, Xiaoguang | Shi, Chenfei | Yan, Wang | Zhang, Limin | Wang, Guoxiang
Antibiotic residues pose a threat to the health of aquatic organisms. The effects and accumulation of antibiotic ciprofloxacin (CIP) in a floating macrophyte (Eichhornia crassipes) under hydroponic conditions were investigated. It was found that E. crassipes exposure to CIP (< 1000 μg L⁻¹) could maintain a stable photosynthesis efficiency. In response to CIP stress, catalase and peroxidase activities of leaves were 7.24–37.51 nmol min⁻¹ g⁻¹ and 98.46–173.16 U g⁻¹, respectively. The presence of CIP did not inhibit the growth of the plant. After 14 days of exposure, tender leaves became white and withered, ascribed to the decline of chlorophyll content and chlorophyll fluorescence parameters. The CIP concentrations, absorbed by E. crassipes, were highest in the roots, followed by white aerial parts and green aerial parts at CIP concentrations of 100 and 1000 μg L⁻¹. These findings demonstrated that E. crassipes could absorb and tolerate CIP in a limited time-scale and imply an alternative solution for phytoremediation in water bodies contaminated with antibiotics.
Show more [+] Less [-]Urea/ZnCl2 in situ hydrothermal carbonization of Camellia sinensis waste to prepare N-doped biochar for heavy metal removal
2019
Guo, Shasha | Gao, Yuefang | Wang, Yancheng | Liu, Zhengjun | Wei, Xingneng | Peng, Pai | Xiao, Bin | Yang, Yajun
Environmental benefits of biochar require a simple and effective method for preparation of functional N-doped biochar. In this study, urea/ZnCl₂ was developed to prepare N-doped biochar via in situ hydrothermal carbonization (HTC) of Camellia sinensis waste at 120–280 °C for 2 h under 1.0–9.8 MPa. Physicochemical and structural properties of the N-doped biochar were investigated by Raman spectra, elemental analysis, BET surface area, SEM, TEM, XRD, and XPS. The results showed that the N content in biochar could reach up to 7.79% at 280 °C. Surface chemistry suggested that pyridinic N, pyrollic N, and graphitic N were the major N species on the biochar. Moreover, the N-doped biochar was successfully employed to remove metal ions Cu²⁺, Pb²⁺, Zn²⁺, and Cr⁶⁺. Adsorption data fit closely to the pseudo-second-order kinetic equation and the Langmuir adsorption isotherm model for all metal ions.
Show more [+] Less [-]Synthesis and characterization of magnetic bio-adsorbent developed from Aegle marmelos leaves for removal of As(V) from aqueous solutions
2019
Sahu, Uttam Kumar | Sahu, Sumanta | Mahapatra, Siba Sankar | Patel, Raj Kishore
A novel magnetic bio-adsorbent was prepared from the leaves of Aegle marmelos tree (Indian bael) and Fe₂O₃ nanoparticles. The AMP@Fe₂O₃ nanocomposite (Aegle marmelos leaf powder) was synthesized by pyrolysis process and applied for As(V) removal through batch adsorption process. The synthesized AMP@Fe₂O₃ nanocomposite was analyzed by several instrumental techniques like XRD, FESEM, TEM, HRTEM, FTIR, BET, and VSM studies. Maximum amount of As(V) was removed at pH 3, contact time of 250 min, adsorbent dose of 0.1 g/L, and initial concentration of 0.5 mg/L at room temperature. The model study revealed that the pseudo-second-order kinetics and Langmuir isotherm models were best fitted with the experimental data. The nanocomposite showed a maximum adsorption capacity of 69.65 mg/g. The endothermic nature of the adsorption process was ascertained from the thermodynamics studies. The zeta potential and FTIR analysis before and after adsorption demonstrated two types of adsorption mechanism. The first one was the electrostatic attraction between negatively charged As(V) ions (H₂AsO₄⁻) and protonated −OH group present on the Fe₂O₃ surface and the second one was ligand exchange between the surface hydroxyl groups and As(V) ions. The AMP@Fe₂O₃ nanocomposite was desorbed with 0.5 M NaOH solutions and also used up to four cycles without any major decrease in removal efficiency. Thus, AMP@Fe₂O₃ nanocomposite can be applied as a potential adsorbent for As(V) removal from wastewater.
Show more [+] Less [-]Synthesis and applications of nano-TiO2: a review
2019
Noman, Muhammad Tayyab | Ashraf, Muhammad Azeem | Ali, Azam
TiO₂-based nanomaterials have attracted prodigious attention as a photocatalysts in numerous fields of applications. In this thematic issue, the mechanism behind the photocatalytic activity of nano-TiO₂ as well as the critical properties have been reviewed in details. The synthesis routes and the variables that affect the size and crystallinity of nano-TiO₂ have also been discussed in detail. Moreover, a newly emerged class of color TiO₂, TiO₂ in aerogel form, nanotubes form, doped and undoped form, and other forms of TiO₂ have been discussed in details. Photocatalytic and photovoltaic applications and the type of nano-TiO₂ that is more suitable for these applications have been discussed in this review.
Show more [+] Less [-]Conversion of organic biomedical waste into value added product using green approach
2019
Patil, Pooja M. | Mahamuni, Pranjali P. | Shadija, Prem G. | Bohara, Raghvendra A.
Sustainable organic biomedical waste management is a difficult challenge as this has become one of the serious hazardous wastes. Improper disposal of organic biomedical waste can lead to direct and indirect transmission of diseases. In the present research, the organic biomedical waste samples (32 g blood swabs, 12 g dressing swabs, and 6 g used cotton) were treated with Azadirachta indica (“Neem”) and Nicotiana tabacum (“Tobacco”) extracts at various concentrations and kept for 96-h degradation, followed by evaluation of physicochemical parameters. The physicochemical results of organic biomedical waste like pH of the experimental sets were within the optimum range and there was 63.33% of decrease of TDS, 86.15% and 95.30% reduction of BOD and COD, respectively was observed at the end of 96 h. The residues were mixed with 1000 g soil to confirm their role as a potential fertilizer. The physicochemical parameters of soil sample F₆ (neem+tobacco) show an excellent result among all. The phytochemical parameters of a plant were also enhanced as compared to control. The soil samples and the tomato plants were also not polluted by the heavy metals, they are within the limit given by WHO. The present study deals with the conversion of organic biomedical waste into potential fertilizer by using plant extracts which can purely be financially profitable to the farmer.
Show more [+] Less [-]Study on habitat suitability of overwintering cranes based on landscape pattern change—a case study of typical lake wetlands in the middle and lower reaches of the Yangtze River
2019
Cui, Yanglin | Dong, Bin | Chen, Lingna | Gao, Xiang | Cui, Yuhuan
Shengjin Lake wetland is located in the middle and lower reaches of the Yangtze River in China. It is a typical lake-type wetland and is also an ideal place for rare cranes to overwintering. The changes of wetland landscape are closely related to the habitat quality of wintering cranes. It is of great significance to study the habitat change of wintering cranes in wetland for wetland ecological restoration and restoration. In this paper, we analyze four kinds of winter cranes and wetland landscape pattern types from the years 1986 to 2015. Also, we adopted the Pearson correlation analysis method to analyze the relationship between wetland landscape types and crane population, and the main landscape types of cranes habitat were obtained. We selected disturbance degree, food richness, vegetation cover, and hydrological condition as the main factors affecting wintering habitat of cranes. We established a habitat suitability index model for wintering cranes and generated habitat suitability assessment maps by ArcGIS. The results show that the change of landscape pattern in Shengjin Lake protected area was obvious, the number of wetland patches increased, the fragmentation degree of landscape increased, the landscape patch difference became smaller, and the diversity index and evenness index increased gradually. From 1986 to 2015, the number of wintering cranes decreased and the habitat suitability index of wintering cranes decreased from 0.845 to 0.465, and the habitat suitability of wintering cranes fell from 13,577.11 to 7424.42 ha, which showed the overall habitat deteriorated significantly and had a positive correlation between the crane population and habitat suitability.
Show more [+] Less [-]Assessing the influence of land use on groundwater pollution based on coefficient of variation weight method: a case study of Shuangliao City
2019
Sun, Ying | Liang, Xiujuan | Xiao, Changlai
In this study, the quality of groundwater was tested in 95 sampling wells in Shuangliao City. Based on the results, the coefficient of variation method was used to calculate the comprehensively evaluated value F, and the grade of groundwater quality, in accordance with the actual scenario in the study area, was classified according to the results of the evaluation. The spatial distribution of groundwater quality types in the study area was classified. In addition, the influence of human activity on each groundwater subsystem was assessed. Combined with the land use types in the study area, the Circle model was used to extract the land use types in the circular buffer zone with a radius of 500 m, and the Kendall rank correlation test was used to analyze the influence of the land use types on the spatial distribution of groundwater pollution. Based on the coefficient of variation, the groundwater quality standard was divided into four sections considering the actual scenario: ≤ 0.92 (I), 0.92~≤ 1.75 (II), 1.75~≤ 2.40 (III), and > 2.40 (IV). Water from class II was considered the main type for groundwater quality. NO₃⁻, TFe, and Mn were deemed the main indexes of groundwater pollution. Further, land use type was found to have a great influence on the spatial distribution of groundwater pollution; specifically, dry land, paddy field, areas with dense traffic, and residential areas are the main land types that affect the groundwater environment.
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