41. 题目: A predictive model for N2O production in anammox-granular sludge reactors: Combined effects of nitrite/ammonium ratio and organic matter concentration
期刊: Journal of Environmental Management
作者: T.D.S. Pereira, R.H. Spindola, C.A.B.S. Rabelo, N.C. Silveira, M.A.T. Adorno, A. Kunz, E.C. Pires, M.H.R.Z. Damianovic
摘要: Once the use of anammox reactors has been increasing on a global scale, it is important to understand the mechanisms of N2O emissions and how to minimise the emissions by optimising the operating conditions. In this study, the influence of chemical oxygen demand (COD) (from 0 mgO2 L−1 to 100 mgO2 L−1) and nitrite/ammonium ratio from 0.79 to 2.21 (maintaining ammonium at 100 mgN L−1 and varying nitrite from 79 mgN L−1 to 221 mgN L−1) in the N2O emissions from anammox-granular sludge reactor was investigated in two steps. Step 1 consisted of batch tests, using central composite design, and Step 2, long-term operation of a 6.5 L continuous up-flow reactor. The results showed that the N2O emissions were minimized by controlling, in the influent, the NO2−-N/NH4+-N ratio from 1.1 to 1.3 and maintaining the COD concentration below 100 mgO2 L−1. TN removal efficiencies were higher than 70% in all conditions tested”.
42. 题目: Contribution of Piriformospora indica on improving the nutritional quality of greenhouse tomato and its resistance against cu toxicity after humic acid addition to soil
期刊: Environmental Science and Pollution Research
作者: Amir Hossein Baghaie, Forough Aghili
摘要: Protected cultivation has a significant contribution in vegetable production. We investigated whether humic acid addition to soil and Piriformospora indica can improve the nutritional quality of greenhouse tomato. We conducted a pot experiment, in which the effects of P. indica inoculation, humic acid addition, and Cu spiking to soil (0, 120, 240, and 500 ppm Cu) were tested. Humic acid addition to soil spiked with 500 ppm Cu decreased the Cu concentration in the fruits of plants inoculated with P. indica from 0.65 to 0.40 mg 100 g Fw-1, which is still above the maximum allowed limits of Cu in tomato by World Health Organization (WHO). The lycopene and ascorbic acid content of tomato fruits were consistently improved by humic acid addition and P. indica inoculation. The antioxidant enzymes' activity changed in response to humic acid addition, Cu spiking to soil, and P. indica inoculation. With increasing Cu level up to 240 ppm, the activity of superoxide dismutase (SOD) and peroxidase (POD) increased significantly. However, with spiking more Cu to soil, the activity of antioxidant enzymes reduced and the MDA content increased significantly. Addition of humic acid to soil and/or presence of P. indica increased the activity of antioxidant enzymes when the soil spiked with 500 ppm Cu. This study indicated that addition of P. indica and humic acid to the soil can enhance the nutritional quality of greenhouse tomato by reduction of Cu toxicity as a common pollutant in the greenhouse media and increasing the antioxidant content of fruits.
43. 题目: Maximum Entropy Modeling to Identify Physical Drivers of Shallow Snowpack Heterogeneity using Unpiloted Aerial System (UAS) Lidar
期刊: Journal of Hydrology
作者: Eunsang Cho, Adam G. Hunsaker, Jennifer M. Jacobs, Michael Palace, Franklin B. Sullivan, Elizabeth A. Burakowski
摘要: Understanding the spatial variability of the snowpack is valuable for hydrologists and ecologists seeking to predict hydrological processes in a cold region. Snow distribution is a function of interactions among static variables, such as terrain, vegetation, and soil properties, and dynamic meteorological variables, such as solar radiation, wind speed and direction, and soil moisture. However, identifying the dominant physical drivers responsible for spatial patterns of the snowpack, particularly for ephemeral, shallow snowpacks, has been challenged due to the lack of the high-resolution snowpack and physical variables with high vertical accuracy as well as inherent limitations in traditional approaches. This study uses an Unpiloted Aerial System (UAS) lidar-based snow depth and static variables (1-m spatial resolution) to analyze field-scale spatial structures of snow depth and apply the Maximum Entropy (MaxEnt) model to identify primary controls over open terrain and forests at the University of New Hampshire Thompson Farm Research Observatory, New Hampshire, United States. We found that, among nine topographic and soil variables, plant functional type and terrain roughness contribute up to 80% and 76% of relative importance in the MaxEnt framework to predicting locations of deeper or shallower snowpacks, respectively, across a mixed temperate forested and field landscape. Soil variables, such as organic matter and saturated hydraulic conductivity, were also important controls (up to 70% and 81%) on snow depth spatial variations for both open and forested landscapes suggesting spatial variations in soil variables under snow can control thermal transfer among soil, snowpack, and surface-atmosphere. This work contributes to improving land surface and snow models by informing parameterization of the sub-grid scale snow depths, down-scaling remotely sensed snow products, and understanding field scale snow states.
44. 题目: Combined foliar and soil selenium fertilizer improves selenium transport and the diversity of rhizosphere bacterial community in oats
期刊: Environmental Science and Pollution Research
作者: Junhui Li, Wenping Yang, Anna Guo, Sheng Yang, Jie Chen, Yuejing Qiao, Sumera Anwar, Kai Wang, Zhenping Yang, Zhiqiang Gao, Jianwu Wang
摘要: Agronomic selenium (Se) biofortification of grain crops is considered the best method for increasing human Se intake, which may help people alleviate Se-deficiency. To investigate the efficiency of agronomic Se biofortification of oat, four Se fertilizer application treatments were tested: topsoil (T), foliar (S), the combination of T and S (TS), and control without Se application (CK). Compared with CK, TS significantly increased the 1000-grain weight, grain yield, Se contents in all parts of oats, contents of soil available N, K, and organic matter by 18%, 8.70%, 19.7-60.2%, 6.00%, 8.02%, and 17.95%, respectively. Leaves, roots, and ears had the highest conversion rate of exogenous Se in S (644.63%), T (416.00%), and TS (273.20%), respectively. TS also increased the activities of soil urease, alkaline phosphatase, and sucrose and the diversity of soil bacterial communities. TS and T increased the relative abundance of bacteria involved in the decomposition of organic matter, such as Actinobacteria, Gemmatimonadetes, Chloroflexi, and Bacteroidetes positively correlated with soil nutrients and enzyme activities, and reduced Proteobacteria and Firmicutes negatively correlated with them, Granulicella, Bacillus, Raoultella, Lactococcus, Klebsiella, and Pseudomonas. Furthermore, TS significantly increased the relative abundance of Planctomycetes, Chlorobi, Nitrospinae, Nitrospirae, Aciditeromonas, Gemmatimonas, Geobacter, and Thiobacter. T significantly increased the abundance of Lysobacter, Holophaga, Candidatus-Koribacter, Povalibacter, and Pyrinomonas. S did not significantly change the bacterial communities. Thus, a combined foliar and soil Se fertilizer proved conducive for achieving higher yield, grain Se content, and improving Se transport, the diversity of rhizosphere bacterial community, and bacterial functions in oats.
45. 题目: Effect of biochar-derived DOM on the interaction between Cu(II) and biochar prepared at different pyrolysis temperatures
期刊: Journal of Hazardous Materials
作者: Xujing Guo, Yuyao Peng, Nanxi Li, Yuanyuan Tian, Lichun Dai, Yi Wu, Yang Huang
摘要: The structure and composition of biochar-derived dissolved organic matter (DOM) at different pyrolysis temperatures differed significantly, affecting the environmental geochemical behavior of heavy metals (HMs). Herein, the binding properties of Cu(II) onto walnut-shell DOM were investigated using spectroscopic methods. The results showed that the DOM at low pyrolysis temperatures (300°C and 500°C) showed higher Cu(II) affinity than that at high pyrolysis temperature (700°C). There was a preferential Cu(II) binding with fulvic-like substances (360nm) at 300°C, and with protein-like materials (275nm) at 500°C and 700°C. The C−O group of alcohols, ethers, and esters showed preferential binding with Cu(II) at 300°C and 700°C pyrolysis temperatures. However, preferential bonding of Cu(II) to the C–O stretching vibration and O–H bending vibration of carboxyl was exhibited at 500°C pyrolysis temperature. Pyrolysis temperature played a crucial role in the release of biochar-derived DOM and in the migration and bioavailability of HMs. Meanwhile, the adsorption effect of Cu(II) increased by 11.2% for biochar at 300°C, and decreased by 15.0% and 61.1% for biochar at 500°C and 700°C, respectively, after the removal of DOM, suggesting that the presence of DOM influenced the adsorption behavior of biochar towards Cu(II).
46. 题目: Achieving enhanced biological phosphorus removal utilizing waste activated sludge as sole carbon source and simultaneous sludge reduction in sequencing batch reactor
期刊: Science of The Total Environment
作者: Zhiwei Fan, Wei Zeng, Qingan Meng, Hong Liu, Hongjun Liu, Yongzhen Peng
摘要: Achieving enhanced biological phosphorus removal dominated by Tetrasphaera utilizing waste activated sludge (WAS) as carbon source could solve the problems of insufficient carbon source and excessive discharge of WAS in biological phosphorus removal. Up to now, the sludge reduction ability of Tetrasphaera remained largely unknown. Furthermore, the difference between traditional sludge fermentation and sludge fermentation dominated by Tetrasphaera was still unclear. In this study, two different sequencing batch reactors (SBRs) were operated. WAS from SBR-parent was utilized as sole carbon source to enrich Tetrasphaera with the relative abundance of 91.9% in SBR-Tetrasphaera. PO43−-P removal and sludge reduction could simultaneously be achieved. The effluent concentration of PO43−-P was 0, and the sludge reduction efficiency reached about 44.14% without pretreatment of sludge. Cell integrity detected by flow cytometry, the increase of DNA concentration in the sludge supernatant and decrease of particle size of activated sludge indicated that cell death and lysis occurred in sludge reduction dominated by Tetrasphaera. Stable structure of activated sludge was also damaged in this process, which led to the sludge reduction. By analyzing the excitation-emission matrix spectra of extracellular polymeric substances and the changes of carbohydrate and protein concentration, this study proved that slowly biodegradable organics (e.g., soluble microbial byproduct, tyrosine and tryptophan aromatic protein) could be better hydrolyzed and acidized to volatile fatty acids (VFAs) in sludge fermentation dominated by Tetrasphaera than traditional sludge fermentation, which provided carbon source for biological nutrients removal and saved operation cost in wastewater treatment.
47. 题目: Organic phosphorus availability shapes the diversity of phoD-harboring bacteria in agricultural soil
期刊: Soil Biology and Biochemistry
作者: Xiaomeng Wei, Yajun Hu, Guan Cai, Huaiying Yao, Jun Ye, Qi Sun, Stavros D. Veresoglou, Yaying Li, Zhenke Zhu, Georg Guggenberger, Xiangbi Chen, Yirong Su, Yong Li, Jinshui Wu, Tida Ge
摘要: In light of the limited resources of phosphorus (P) fertilizer, investigating the response of organic P (Po)-mineralizing microbial communities on the resource supply can be an avenue to optimize P recycling in agricultural systems. The alkaline phosphomonoesterase (alkaline PAse)-encoding gene PhoD is universally occurring in soil microorganisms. Here we collected 102 soil samples from Chinese agricultural fields to explore the effect of resource supply on the community of phoD-harboring bacteria. The relationships between the community diversity and soil organic carbon (SOC), total nitrogen (TN) and available Po concentration were fitted to the linear and quadric models suggested by the resource competition theory as well as the Michaelis-Menten model suggested by the metabolic theory of ecology. The results revealed that the response of phoD-harboring bacterial diversity to SOC and TN was likely related to the resource competition theory, with highest diversity at moderate SOC and TN concentration. In contrast, the phoD diversity increased with increasing available Po until the stationary value, which was consistent with the metabolic theory of ecology. Random forest models and multiple regression tree analyses identified the Po availability as the most important predictor on the variation of the phoD-harboring bacterial diversity and network topological features prior to the climate, soil texture, pH and all tested soil nutrient variables. This study highlights the critical role that Po plays in structuring phoD-harboring bacterial communities. Furthermore, for the first time, we correlated functional gene diversity to the corresponding enzymatic substrate availability from a metabolic theory perspective, confirming that the relationship follows the Michaelis-Menten model which was well known to predict the substrate regulation on the rate of enzymatic reactions.
48. 题目: A new method for multicolor determination of organic matter in moist soil
作者: Lixin Lin, Zhiqiu Gao, Xixi Liu, Yuan Sun
摘要: Soil color is frequently used by researchers to determine soil properties such as soil organic matter (SOM). However, soil moisture can darken soil color, which seriously limits the accuracy of SOM estimates. This study focused on the influence of soil moisture on the SOM estimate by using our new moisture-based multicolor reconstruction (MMR) method. On the basis of RGB color and moisture values of moist soil samples, the optimal MMR (moist soil) model—root mean square error of validation = 4.537 g/kg, residual prediction deviation of validation = 1.681, ratio of performance to interquartile range of validation = 2.939—was obtained to develop the final model, which performed better than the RGB (moist soil) model. Our method can reduce the influence of soil moisture and increase accuracy for multicolor modeling, and explores a new way to accurately determine the SOM content.
49. 题目: Enhanced degradation of petroleum hydrocarbons by immobilizing multiple bacteria on wheat bran biochar and its effect on greenhouse gas emission in saline-alkali soil
作者: Saisai Guo, Xiaomei Liu, Jingchun Tang
摘要: In this study, an immobilization method for forming and keeping dominant petroleum degradation bacteria was successfully developed by immobilizing Pseudomonas, Acinetobacter, and Sphingobacterium genus bacteria on wheat bran biochar pyrolyzed at 300, 500, and 700 °C. The removal efficiency indicated that the highest TPHs (total petroleum hydrocarbons) removal rate of BC500–4 B (biochar pyrolyzed at 500 °C with four kinds of petroleum bacteria) was 58.31%, which was higher than that of BC500 (36.91%) and 4 B (43.98%) used alone. The soil properties revealed that the application of biochar increased the content of organic matter, available phosphorus, and available potassium, but decreased pH and ammonium nitrogen content in soil. Bacterial community analysis suggested that the formation of dominant degrading community represented by Acinetobacter played key roles in TPHs removal. The removal rate of alkanes was similar to that of TPHs. Besides, biochar and immobilized material can also mediate greenhouse gas emission while removing petroleum, biochar used alone and immobilized all could improve CO2 emission, but decrease N2O emission and had no significant impact on CH4 emission. Furthermore, it was the first time to found the addition of Acinetobacter genus bacteria can accelerate the process of forming a dominant degrading community in wheat bran biochar consortium. This study focused on controlling greenhouse gas emission which provides a wider application of combining biochar and bacteria in petroleum soil remediation.
50. 题目: Research progress and prospects for using biochar to mitigate greenhouse gas emissions during composting: A review
期刊: Science of The Total Environment
作者: Yanan Yin, Chao Yang, Mengtong Li, Yucong Zheng, Chengjun Ge, Jie Gu, Haichao Li, Manli Duan, Xiaochang Wang, Rong Chen
摘要: Biochar possesses a unique porous structure and abundant surface functional groups, which can potentially help mitigate greenhouse gas (GHG) emissions from compost. This review summarizes the properties and functions of biochar, and the effects of biochar on common GHGs (methane (CH4), carbon dioxide (CO2), and nitrous oxide (N2O)) and ammonia (NH3, an indirect GHG) during composting. Studies have shown that it is possible to improve the mitigation of GHG emissions during composting by adjusting the biochar amount, type of raw material, pyrolysis temperature, and particle size. Biochar produced from crop residues and woody biomass has a greater effect on mitigating CH4, N2O, and NH3 emissions during composting, and GHG emissions can be reduced significantly by adding about 10% (w/w) biochar. Biochar produced by high temperature pyrolysis (500–900 °C) has a greater effect on mitigating CH4 and N2O emissions, whereas biochar generated by low temperature pyrolysis (200–500 °C) is more effective at reducing NH3 emissions. Interestingly, adding granular biochar is more beneficial for mitigating CH4 emissions, whereas adding powdered biochar is better at reducing NH3 emissions. According to the current research status, developing new methods for producing and using biochar (e.g., modified or combined with other additives) should be the focus of future research into mitigating GHG emissions during composting. The findings summarized in this review may provide a reference to allow the establishment of standards for using biochar to mitigate GHG emissions from compost.
51. 题目: Rapid Start-Up Strategy of Partial Denitrification and Microbially Driven Mechanism of Nitrite Accumulation Mediated by Dissolved Organic Matter
期刊: Bioresource Technology
作者: Li Zhang, Shiwei Hao, Yueping Wang, Shuang Lan, Quanhao Dou, Yongzhen Peng
摘要: The rapid start-up of Partial denitrification (PD; nitrate to nitrite) was investigated based on the analysis of microbially driven mechanism of nitrite accumulation mediated by Dissolved organic matter (DOM) in this study. The nitrate to Nitrite transformation ratio (NTR) > 90% and effluent nitrate < 5 mg/L were achieved in 17days by feeding with lower nitrate of ∼35 mg/L and removing the idling period. And the enhanced nitrite accumulation when applying the above strategy is related to the decreased utilization of the aliphatic DOM during nitrite reduction process. Additionally, the rapid enriched Thauera and OLB13 (37.21%) and inhibited norank_f__Blastocatellaceae (2.86%), and the increased disparity (2.0-fold) between the genes involved in nitrite generation (e.g., narH) and for nitrite reduction (e.g., nirK) jointly contributed to PD start-up. While the genes (e.g., DLD) related to producing electrons from aliphatic DOM also up-regulated by 0.1-fold, which led to the increased nitrate removal and NTR.
52. 题目: Microbial community transcriptional patterns vary in response to mesoscale forcing in the North Pacific Subtropical Gyre
期刊: Environmental Microbiology
作者: Matthew J. Harke, Kyle R. Frischkorn, Gwenn M. M. Hennon, Sheean T. Haley, Benedetto Barone, David M. Karl, Sonya T. Dyhrman
摘要: The physical and biological dynamics that influence phytoplankton communities in the oligotrophic ocean are complex, changing across broad temporal and spatial scales. Eukaryotic phytoplankton (e.g., diatoms) despite their relatively rare occurrence in oligotrophic waters, are responsible for a large component of the organic matter flux to the ocean interior. Mesoscale eddies can impact both microbial community structure and function, enhancing primary production and carbon export, but the mechanisms that underpin these dynamics are still poorly understood. Here, mesoscale eddy influences on the taxonomic diversity and expressed functional profiles of surface communities of microeukaryotes and particle-associated heterotrophic bacteria from the North Pacific Subtropical Gyre were assessed over two years (spring 2016 and summer 2017). The taxonomic diversity of the microeukaryotes significantly differed by eddy polarity (cyclonic versus anticyclonic) and between sampling seasons/years and was significantly correlated with the taxonomic diversity of particle-associated heterotrophic bacteria. The expressed functional profile of these taxonomically distinct microeukaryotes varied consistently as a function of eddy polarity, with cyclones having a different expression pattern than anticyclones, and between sampling seasons/years. These data suggest that mesoscale forcing, and associated changes in biogeochemistry, could drive specific physiological responses in the resident microeukaryote community, independent of species composition.
53. 题目: Soil carbon and plant richness relationships differ among grassland types, disturbance history and plant functional groups
作者: B. L. Anacker, T. R. Seastedt, T. M. Halward, A. L. Lezberg
摘要: Understanding the relationship of soil carbon storage and species diversity in grasslands can provide insights into managing these ecosystems. We studied relationships among soil C and plant species richness within ~ 9700 ha of grasslands in Colorado, US. Using 141 grassland transects, we tested how soil C was related to plant species richness, grassland type, soil texture, and prairie dog presence. Soil C was significantly, positively related to plant species richness, while native perennial graminoid species richness exhibited an even stronger positive relationship. However, the relationship of soil C and plant richness was not found in all three grassland types studied, but instead was unique to the most common grassland type, mixed grass prairie, and absent from both xeric tallgrass and mesic tallgrass prairie. The presence of a single indicator species, Andropogon gerardii , showed a significant, positive relationship with soil carbon. Our best possible model explained 45% of the variance in soil C using species richness, grassland type, and their interaction. Surprisingly, soil C was negatively related to soil clay, suggesting that surface clays amplify evaporation and water runoff rather than protecting soil organic matter from decomposition. Soil C was negatively related to prairie dog presence, suggesting that prairie dogs do not enhance soil carbon sequestration; in fact, prairie dog occupied sites had significantly lower soil C, likely related to loss of topsoil from prairie dog colonies. Our results suggest that management for species richness provides the co-benefit of soil C storage, and high clay and prairie dog disturbance compromises both.
54. 题目: Microstructure characteristics of aggregates and Cd immobilization performance under a 3–year sepiolite amendment: A field study
期刊: Science of The Total Environment
作者: Wang Runlong, Zheng Shunan, Sun Tong, Xu Yingming, Sun Tao, Sun Yuebing
摘要: Sepiolite is an efficient mineral for the immobilization of Cd in contaminated soils. Here, we conducted a 3–year field experiment to investigate the effect of sepiolite on soil aggregation and porosity, Cd availability, and organic carbon content in the bulk and aggregate soils and Cd accumulation by leafy vegetables. The sepiolite–treated soils showed a 15.4%–53.4% and 5.5%–63.0% reduction in available Cd content in the bulk soil and different particle–size aggregates, respectively. Moreover, the Cd concentrations in the edible parts of Brassica campestris, Lactuca sativa L., and Lactuca sativa var. ramosa Hort. decreased by 5.9%–26.2%, 22.8%–30.1%, and 14.4%–19.1%, respectively, compared with those of the control groups. Treatment with 0.5%–1.5% sepiolite resulted in a significant increase (P < 0.05) in the proportion of 0.25–5.0 mm aggregates, and the increase in the mean weight diameter and geometric mean weight of the soil aggregates indicated that sepiolite treatments enhanced soil aggregate stability. Furthermore, three–dimensional X–ray computed tomography imaging showed that sepiolite treatments resulted in an increase in the total area, average size, and pore perimeter of aggregates, with the maximum values being 1.63–, 1.41–, and 1.401–fold higher than those of the corresponding control groups, respectively. The highest values of soil organic carbon and particulate organic carbon were obtained in 1.5% sepiolite–treated soils and were 2.07– and 1.91–fold higher than those of the control group, respectively. Additionally, the level of organic carbon functional groups in the bulk soil and different particle–size aggregates generally increased with increasing sepiolite application. Overall, sepiolite, as a soil amendment, not only reduced toxic element bioavailability and uptake by plants but also enhanced soil structure and function.
55. 题目: Efficacy of rhizobacterial exopolysaccharides in improving plant growth, physiology, and soil properties
期刊: Environmental Monitoring and Assessment
作者: Abubakar Dar, Zahir Ahmad Zahir, Muhammad Iqbal, Atif Mehmood, Atif Javed, Azhar Hussain, , Maqshoof Ahmad
摘要: The current study investigated the influence of exopolysaccharides (EPSs) producing plant growth–promoting rhizobacteria (PGPR) on the growth, physiology, and soil properties. The pre-isolated and compatible EPS producing PGPR strains were first screened based on improvement in soil aggregates in an incubation study. The screened strains (Rhizobium phaseoli strain Mn-6, Pseudomonas bathysetes strain LB5, and unidentified strain R2) were then employed in pot study for assessing improvements in maize growth, physiology, and soil properties. Eight treatments including T1 = control, T2 = Mn-6, T3 = R2, T4 = LB5, T5 = Mn-6 + R2, T6 = Mn-6 + LB5, T7 = R2 + LB5, and T8 = Mn-6 + R2 + LB5 were applied in completely randomized design (CRD) hexa replicated (half for root and half for soil, and yield attributes). The results depicted that among various treatments, the application of PGPR strain Mn-6 increased plant height, root length, root fresh and dry weight, root length density, SPAD value, leaf areas index, photosynthesis rate, transpiration, and stomatal conductance by 24, 79, 72, 90, 49, 35, 23, 21, 75, and 77%, respectively, compared with non-inoculated treatment. Similarly, significant improvement in maize yield and soil physical properties was also observed in response to the application of EPS-producing PGPR. Therefore, it is concluded that the application of EPS producing PGPR is an effective strategy to improve plant growth, physiology, yield, and soil physical properties. Moreover, EPS-producing PGPR should be exploited in field studies for their potential in improving plant growth and soil properties.
56. 题目: Study on the nonradical pathways of nitrogen-doped biochar activating persulfate for tetracycline degradation
期刊: Separation and Purification Technology
作者: Quanfa Zhong, Qintie Lin, Wenjie He, Hengyi Fu, Zhuofan Huang, Yupeng Wang, Libin Wu
摘要: Tetracycline (TC) is a kind of refractory pollutant and widely exists in environment, and it is urgent to develop effective methods for TC treatment. In this study, nitrogen-doped biochar (N-BCX) was successfully synthesized and was used to activate persulfate (PS) to degrade TC. The materials were characterized by XPS, Raman spectrum, SEM, BET and FT-IR. SEM and BET results showed that the catalyst had an obvious pore structure and large specific surface area, which increased with increasing pyrolysis temperature. Nitrogen doping could increase the content of graphite-N in biochar; the defect edge of the material increased, further formed the graphitization structure, and enhanced the catalytic performance of the material. TC (20 mg/L) could be completely removed within 120 min under the optimal conditions of 200 mg/L of catalyst dosage, 2 mM of PS dosage and initial pH of 7. The results of EPR, quenching experiments and electrochemical experiments showed that the degradation of TC in the system did not depend on the action of radicals, the electron transfer between TC and PS on the surface of biochar maybe the main pathway. Efficient and environmentally friendly nitrogen-doped biochar can provide a reference for the related antibiotic wastewater treatment.
57. 题目: Starch and powdered activated carbon amended alginate-biomass beads for metronidazole and bulk organic matter removal: Synthesis, optimization, reaction kinetics and reusability
期刊: Journal of Environmental Chemical Engineering
作者: Sudeeptha Girijan, Mathava Kumar, Shweta Gomber
摘要: In this work, biomass immobilized alginate beads were amended with various ratios of starch (0-20%) and powdered activated carbon (PAC: 0-0.1%), and optimum compositions were shortlisted based on simultaneous removal of metronidazole (MNZ) and organic matter from synthetic wastewater. MNZ removal of greater than 80% was achieved for initial MNZ concentration of 1ppm in 3d with optimum PAC (0.1%) and starch (5%) ratios. The presence of additional carbon substrate (i.e., dextrose) had improved the MNZ removal efficiency. Subsequently, the experiments were conducted with alginate beads amended with 0.1% PAC (A1-C2), 5% starch (A1-S1) and combination of 0.1% PAC and 5% starch (A1-S1-C2) The MNZ removal by PAC and starch amended beads was found to follow the second-order and first-order kinetics, respectively. Compared to starch amended beads, average MNZ, organic carbon and nitrogen removal efficiencies of PAC amended beads were higher by 12%, 32% and 5%, respectively. Moreover, reusability study had shown better stability of PAC (8 cycles) compared to starch (3 cycles). When starch and PAC were added together, the removal efficiencies were better than starch but lower than PAC except in the case of ammonia removal. Among the shortlisted beads, A1-C2 was found to perform best in MNZ, TOC and ammonia removals. PAC addition improved MNZ removal efficiency and the MNZ removal rate. The involvement of both adsorption and biodegradation were established in MNZ removal in all types of beads by FTIR and LC-MS analysis, respectively. However, simultaneous and rapid removal of MNZ as along with organic carbon by adsorption paired with subsequent biodegradation demonstrate the applicability of A1-C2 for the treatment of PPCP laden wastewaters.
58. 题目: Characterization of Dissolved Organic Matter and Its Derived Disinfection Byproduct Formation along the Yangtze River
期刊: Environmental Science & Technology
作者: Chao Fang, Xu Yang, Shunke Ding, Xinmiao Luan, Rong Xiao, Zhenqi Du, Pin Wang, Wei An, Wenhai Chu
摘要: The Yangtze River basin covers one-fifth of China’s land area and serves as a water source for one-third of China’s population. During long-distance water transport from upstream to downstream, various sources of dissolved organic matter (DOM) lead to considerable variation in DOM properties, significantly impacting water treatability and disinfection byproduct (DBP) formation after chlorination. Using size-exclusion chromatography and fluorescence spectroscopy, the spatial variation in DOM characteristics was comprehensively investigated on a basin scale. The formation of 36 DBPs and speciated total organic halogen in chlorinated samples was determined. Overall, the Yangtze River waters featured a high proportion of terrestrially derived humic substances that served as important precursors for trihalomethanes and haloacetic acids, which was responsible for the increase in total DBP formation along the Yangtze River. The downstream waters were characterized by high levels of microbially derived protein-like biopolymers, which significantly contributed to the formation of haloacetaldehydes and haloacetonitriles that dominated DBP-associated mammalian cell cytotoxicity. Moreover, the precursors of haloacetaldehydes and haloacetonitriles in downstream waters were highly hydrophilic, posing a challenge for water treatment. This study presents an extensive basin-scale study, providing insights into DOM variations along the Yangtze River, illustrating the impact of DOM properties on drinking water from a DBP perspective.
59. 题目: Ameliorative photocatalytic dye degradation of hydrothermally synthesized Bimetal Ag-Sn Hybrid Nanocomposite treated upon domestic wastewater under visible light irradiation
期刊: Journal of Hazardous Materials
作者: Rajesh Pandiyan, Selvakumar Dharmaraj, Sivasankaran Ayyaru, Abimanyu Sugumaran, Jeevasree Somasundaram, Amsa Samreen Kazi, Sumathi C. Samiappan, Veeramuthu Ashokkumar, Chawalit Ngamcharussrivichai
摘要: Industrial and textile dyes are the major source of water pollutants in the Coimbatore Districts of Tamil Nadu, India. The highly stable organic dyes from these industries are being discharged untreated into neighboring rivers, lakes, and ponds. Thus, the present study mainly focused on the preparation of Bimetal Nanocomposite (Ag-Sn) through Free-facile Teflon autoclave methodology and their subsequent stimulation has given to the photocatalyst by visible light irradiation. This visible light stimulates and irradiates the photocatalysts from steady state to the excited state and might help in absorption of the nanosized dye materials and organic matter. The nanocomposite was characterized using UV, FTIR, Zeta-sizer, XRD and FE-SEM. These parameters exhibited significant lattice structures with an average size of 127.6nm. Further the nanocomposite treated samples were tested for water quality parameters like TDS, BOD, COD, heavy metals, sedimentation rate and bacterial population. Likewise, the samples irradiated with visible light for photocatalytic activity exhibited a significant intensity of C/C0 at 0.42 and 0.28. The treated water used for green gram seedling assay exhibited significant growth. Scavengers from Ag-Sn bimetal nanocomposite plays the major role in dye degradation. The results clearly suggest that Ag-Sn Bimetal nanocomposite can be used for wastewater treatment and the subsequent treated water can be utilized for agriculture purposes.
60. 题目: Exploring the application of TEX86 and the sources of organic matter in the Antarctic coastal region
期刊: Organic Geochemistry
作者: Ana Lúcia L. Dauner, B. David A. Naafs, Richard D. Pancost, César C. Martins
摘要: Isoprenoidal glycerol dialkyl glycerol tetraethers (isoGDGTs) are archaeal biomarkers. In many settings, the degree of cyclization of isoGDGTs is correlated with temperature, forming the basis of the TEX86 paleothermometer that is widely used to reconstruct sea surface temperature (SST) across a range of time scales. However, the application of TEX86 to the polar regions is relatively limited and there is currently no consensus on which calibration is best suited for polar environments. In addition, application of TEX86 to the polar regions is complicated by uncertainty regarding the source of organic matter input in coastal polar environments. We tested five different calibrations for TEX86 in marine sediments from the Antarctic coastal region of Admiralty Bay near King George Island, using four short cores that span the second half of the 20th century. We also explored the possible sources of organic matter in these cores using sterol biomarkers. Best results for TEX86 were obtained using a quadratic calibration. The TEX86 signal presented a strong seasonal signal and best matched reanalysis temperatures of the austral spring season (Oct-Nov-Dec). The most abundant compounds observed in the sediments were the sterols cholest-5-en-3β-ol and 24-ethylcholest-5-en-3β-ol, the fatty alcohols C16 and phytol, and isoGDGT-0, indicating a dominant marine origin of the organic matter. Differences in their vertical distributions suggests that some compounds (such as cholest-5-en-3β-ol and phytol) may have had different sources over the evaluated period. Together our results indicate that TEX86 can be used to reconstruct SSTs in the Antarctic coastal region.