101. 题目: The unravelling of radiocarbon composition of organic carbon in river sediments to document past anthropogenic impacts on river systems
期刊: Science of The Total Environment
作者: Yoann Copard, Frédérique Eyrolle, Cécile Grosbois, Hugo Lepage, Loic Ducros, Amandine Morereau, Nathan Bodereau, Catherine Cossonnet, Marc Desmet
摘要: As carriers of dissolved and particulate loads that connect continental surfaces to oceans, river systems play a major role in the global carbon cycle. Indeed, riverine particulate organic carbon (POC) is a melange of various origins characterized by their own 14C labeling. In addition, civil nuclear activities have brought new 14C source that remains poorly documented. We propose to unravel the Δ14C value of POC stored in a sedimentary archive collected downstream the most nuclearized European rivers (the Loire River). We postulate that riverine POC is a mixture of aquatic POC (which could be impacted by the liquid discharge from nuclear industry), terrestrial and petrogenic POC. With a combination of radiocarbon measurements, POC analyses and the palynofacies method, we assessed the respective Δ14C value of the POC origins. The gaps between the Δ14C values of the sedimentary POC and those of the atmosphere were the result of the dilution from dead-C, the freshwater reservoir effect imprinting the Δ14C of aquatic POC and the age and transit time of terrestrial POC within the catchment. Importantly, we consider that the unravelling of radiocarbon composition of riverine POC could be useful to determine either the transit time of material from source to sink, some past industrial or natural events, the resilience of the river system and milestones of the social and economic trajectory of a catchment. For the last three decades, riverine sediments could also act as a source of radiocarbon for the atmosphere.
102. 题目: Biochar Co-doped with Nitrogen and Boron Switching the Free Radical Based Peroxydisulfate Activation into the Electron-Transfer Dominated Nonradical Process
期刊: Applied Catalysis B: Environmental
作者: Jibo Dou, Jie Cheng, Zhijiang Lu, Ziqi Tian, Jianming Xu, Yan He
摘要: In this study, N/B co-doped biochars were employed as metal-free activators of peroxydisulfate (PDS) for tetracycline degradation, more importantly, the roles of dopants and the relative contribution of radical vs nonradical oxidations were comprehensively investigated. Integrating with electron paramagnetic resonance and kinetics calculations, we showed that co-doping N and B into biochars not only boosted the catalytic activity but also switched the radical PDS-activated process into the electron transfer-dominated nonradical process. Compared with pristine biochar/PDS systems (22%), the nonradical contribution of N/B co-doped biochar/PDS systems increased to 59%, exhibiting outstanding stability and selectivity. Galvanic oxidation tests and theoretical simulations unveiled that doped biochars as conductive tunnels accelerate the potential difference-driven electron transfer from the highest occupied molecular orbital of pollutants to the lowest unoccupied molecular orbital of PDS due to the lower energy gap. This study provided new insights into the critical role of heteroatom-doped carbocatalysts in PDS nonradical activation.
103. 题目: Evaluation of organic indicators derived from extractable, hydrolysable and macromolecular organic matter in sedimentary tsunami deposits
期刊: Marine Geology
作者: Olga Konechnaya, Piero Bellanova, Mike Frenken, Klaus Reicherter, Jan Schwarzbauer
摘要: Due to the high population density and sensitive infrastructures, coastal areas are highly vulnerable to various geohazards such as tsunamis. The impact of tsunamis is traceable in sedimentary archives providing an important tool for reconstructing these events. Here, geochemical and physical evidence of the resulting inundations have been discussed over the last years with increasing interest on identifying and using highly specific tsumanite indicators. To investigate a broader range of potential organic indicators, a multi-tiered geochemical analysis has been applied on tsunami deposit from Japan and Hawaii in this study with the aim to detect and quantify a more comprehensive set of suitable marker compounds. Both areas of investigation differed especially in terms of population and anthropogenic influence. The analyzed fractions of organic matter covered not only the low molecular weight compounds of the extractable and hydrolysable fraction (a part of the non-extractable fraction), but also the macromolecular matter. Three consecutive analytical approaches including extraction, alkaline hydrolysis and pyrolysis have been applied on the sedimentary organic matter to study their potential to contrast between tsunami and non-tsunami layers. The analyses of compound ratios as well as individual concentration profiles in tsunami and non-tsunami layers revealed two parameters, the TARFA (terrigenous to aquatic ratio of fatty acids) and the C29/C27 sterol ratio, which exhibit a high potential to act as tsunamite indicators. Further parameters (TARALK - terrigenous to aquatic ratio of n-alkanes, concentration profiles of long-chain n-aldehydes) showed a minor potential but are worth to be considered in organic geochemical analyses of tsunami affected sediment archives in the future.
104. 题目: Sources and fate of organic matter in a hypersaline lagoon: A study based on stable isotopes from the Pulicat lagoon, India
期刊: Science of The Total Environment
作者: Santrupta Samantaray, Prasanta Sanyal
摘要: Stable carbon (δ13C) and nitrogen (δ15N) isotopes of organic matter (OM) in bed sediments and suspended solids are thoroughly investigated in the Pulicat lagoon, India, in pre-South West (SW) monsoon (June 2018) and post-North East (NE) monsoon (March 2019) to understand the response of OM in salt stress conditions. A near absence of an external supply of water and intense evaporation, as suggested by higher hydrogen and oxygen isotope values (δD and δ18O) of the lagoon water, led to hypersaline conditions in the lagoon. Despite a long period of osmotic stress, a high OM concentration in suspended solids in post-NE monsoon suggests that autochthonous production is unaffected by salt stress conditions. Locally at different sites, the difference in δ13C (−4.9‰ to +1.4‰) and δ15N (−4.1‰ to +1.6‰) values of OM between suspended solids and bed sediments are higher in pre-SW monsoon compared to post-NE monsoon. The negative isotopic difference is caused by benthic respiration of OM and cation exchange with clay bound ammonium in bed sediments, whereas the positive difference is the result of cellulose decomposition in areas dominated by seagrasses. However, in post-NE monsoon, wind-induced re-suspension of bed sediments reduce the differences in δ13C (−2.3‰ to −0.1‰) and δ15N (−2.1‰ to +3‰) values. The source apportionments of δ15N values suggest inputs from sewage and fertilizers. Additionally, seagrass-detritus dislodged by fishing activities favors primary production. Overall, we suggest that the impact of the hypersaline conditions on in-situ productivity can be suppressed if wind activity and nutrient re-cycling are dominant. The present study is unique as it addresses the processes that operate in a hypersaline lagoon during the short-term failure of monsoon.
105. 题目: Variability of dissolved organic matter in two coastal wetlands along the Changjiang River Estuary: Responses to tidal cycles, seasons, and degradation processes
期刊: Science of The Total Environment
作者: Xiaohui Zhang, Fang Cao, Ying Huang, Jianwu Tang
摘要: Dissolved organic matter (DOM) in the coastal tidal marsh–estuary systems are complex mixtures with different source materials that vary with hydrological regimes, seasons, and environmental conditions and are modified by removal processes including photochemical and microbial degradations. Here, monthly surveys of DOM and its optical properties (i.e., absorbance and fluorescence of DOM) covering a complete semi-diurnal tidal cycle were conducted in two coastal marshes with distinct hydrological regimes (i.e., one freshwater and one brackish marsh) in the Changjiang River Estuary (CRE). Four fluorescent components were identified by excitation–emission matrix fluoresces combined with parallel factor analysis (EEMs–PARAFAC) as two terrestrial humic-like components and two autochthonous protein-like components. Results indicated that ebbing waters draining the marshes were consistently enriched with highly absorbing, more humic and highly aromatic DOM compared to the flood tidewaters. On a seasonal basis, DOM dynamics were largely modulated by the marsh productivity and the seasonal Changjiang runoff. Protein-like fluorophores, however, demonstrated a constant, less variable pattern on both the tidal and seasonal timescales. Onsite water incubation experiments with photochemical and microbial alterations revealed that photochemistry was primarily responsible for the removal of optically active components in the marsh DOM pools whereas the impact of microbes was minor. Principal component analysis (PCA) illustrated the processes regulating the DOM dynamics at the marsh–estuarine interface and allowed a clear distinction of samples between the two marshes, in addition to the samples under the influence of episodic weather events (i.e., Super Typhoon Lekima in summer 2009 and the basin-wide severe flood event occurred in summer 2020). This study underscores the importance of world large-rivers such as Changjiang on estuarine marsh DOM dynamics and also highlights the substantial heterogeneity of the marsh DOM across a river-dominated estuary.
106. 题目: Key Cr species controlling Cr stability in contaminated soils before and chemical stabilization at a remediation engineering site
期刊: Journal of Hazardous Materials
作者: Danni Li, Guanghe Li, Yuning He, Yingshuang Zhao, Qiuci Miao, Hao Zhang, Ying Yuan, Dayi Zhang
摘要: Linking chromium (Cr) speciation with its stability in soils is vital because insoluble Cr(VI) and chemical adsorbed Cr(VI) could hinder the remediation efficiency and release Cr(VI) for a prolonged period of time. In this study, we investigated key Cr species to probe the mechanisms controlling the release of insoluble Cr(VI) at Cr-contaminated sites using synchrotron-based X-ray absorption near-edge structure (XANES) for the first time. Chromite, stichtite and Cr-silicate were predominant forms of Cr(III). Insoluble Cr(VI) was hosted by layered double hydroxides (LDHs) such as brownmilerite and hydrotalcite. Anion competition tests documented a substitution of absorbed Cr(VI) by SO42- and NO3-. Acid extraction released 6.7-25.7% more Cr(VI) than anion extraction, possibly attributing to the erosion of LDH and CaCrO4 in calcite rather than Cr-bearing minerals. Brown and red soils released maximally 62% and 44% of total Cr(VI) by 10mol/(kg soil) and 2mol/(kg soil) of H+, respectively. SO42-, H2O and H+ contributed to more release of total Cr(VI) in brown soils (22%, 33% and 7%) than red soils (25%, 17% and 2%). More crystalline Cr structures were found after chemical stabilization, indicating a higher Cr stability in chemically stabilized soils. Cr and Mn exhibited an overlapped distribution pattern in both contaminated and chemically stabilized soils, hinting at the re-oxidation of Cr(III). Insoluble Cr(VI) could be released by acidic rainfalls and soil organic matters, posing potential threats to Cr long-term stability in field-scale remediation.
107. 题目: Labile carbon facilitated phosphorus solubilization as regulated by bacterial and fungal communities in Zea mays
期刊: Soil Biology and Biochemistry
作者: Yanlan Huang, Zhongmin Dai, Jiahui Lin, Daming Li, Huicai Ye, Randy A. Dahlgren, Jianming Xu
摘要: Organic carbon (C) is often applied to agricultural soils to increase soil organic matter, however, its mechanistic effects on soil P transformations and availability resulting from stimulation of microbial activities and changes in microbial communities remain uncertain. This study investigated the responses of soil P availability, P fractions and phoD harboring bacterial and fungal communities to two dose rates (5 and 10 mg C g−1 dry soil) of labile C (glucose) in bulk and rhizosphere soils planted with maize in a P-deficient soil (Oxisol). Both doses of glucose significantly increased available P concentrations (over a 47-day period) in soils without maize, and in the bulk and rhizosphere soils of maize, resulting in the promotion of maize growth. Glucose additions altered soil phoD harboring bacterial and fungal community composition and stimulated the growth of keystone P-solubilizing microorganisms, such as Bradyrhizobium and Eupenicillium, in soils with maize. Co-occurrence network analysis showed that glucose enhanced interactions between phoD harboring bacterial taxa relative to that of fungal taxa, whether in individual networks or in combined networks. Our results highlight the importance of labile C in facilitating changes in soil P-solubilizing bacterial and fungal communities of a P-deficient soil. These findings provide crucial information to guide P-cycling management strategies via microbial regulation in agro-ecosystems.
108. 题目: Water-Phase Exfoliated Biochar Nanofibers from Eucalyptus Scraps for Electrode Modification and Conductive Film Fabrication
期刊: ACS Sustainable Chemistry & Engineering
作者: Qurat Ul Ain Bukhari, Filippo Silveri, Flavio Della Pelle, Annalisa Scroccarello, Daniele Zappi, Enrico Cozzoni, Dario Compagnone
摘要: A solvent-free strategy to produce water-dispersed biochar-nanofibers (BH-CNF) is reported, demonstrating the potential of this cost-effective and sustainable material in electrochemical sensing and fabrication of conductive films. Water-phase BH-CNF from eucalyptus scraps were achieved using a Kraft process followed by liquid-phase exfoliation assisted by the biological stabilizing agent sodium cholate. BH-CNF-based sensors were constructed following two strategies: surface modification of screen-printed electrodes and fabrication of exclusively nanofiber-based flexible sensors. The latter were fabricated through a procedure that is cost-effective and within everyone’s reach. The potentiality of the BH-CNF-based sensors has been challenged toward a wide range of analytes containing phenol moieties and applied for detection of o-diphenols and m-phenols in olive oil samples. The BH-CNF-based sensors exhibited repeatable (RSD ≤ 7%, n = 5) and reproducible (RSD ≤ 10%; n = 3) results, proving their applicability in electroanalytical applications and the robustness of the exfoliation and fabrication strategy. For sample analysis, LODs for hydroxytyrosol (LOD ≤ 0.6 μM) and tyrosol (LOD ≤ 3.8 μM), intersensor precision (RSD calibration slope < 7%, n = 3), and recoveries obtained in real sample analysis (91–111%, RSD ≤ 6%; n = 3) endorse the material exploitability in real analytical applications.
109. 题目: Litter inputs and phosphatase activity affect the temporal variability of organic phosphorus in a tropical forest soil in the Central Amazon
期刊: Plant and Soil
作者: Karst J. Schaap, Lucia Fuchslueger, Marcel R. Hoosbeek, Florian Hofhansl, Nathielly Pires Martins, Oscar J. Valverde-Barrantes, Iain P. Hartley, Laynara F. Lugli, Carlos Alberto Quesada
摘要: Purpose The tropical phosphorus cycle and its relation to soil phosphorus (P) availability are a major uncertainty in projections of forest productivity. In highly weathered soils with low P concentrations, plant and microbial communities depend on abiotic and biotic processes to acquire P. We explored the seasonality and relative importance of drivers controlling the fluctuation of common P pools via processes such as litter production and decomposition, and soil phosphatase activity. Methods We analyzed intra-annual variation of tropical soil phosphorus pools using a modified Hedley sequential fractionation scheme. In addition, we measured litterfall, the mobilization of P from litter and soil extracellular phosphatase enzyme activity and tested their relation to fluctuations in P- fractions. Results Our results showed clear patterns of seasonal variability of soil P fractions during the year. We found that modeled P released during litter decomposition was positively related to change in organic P fractions, while net change in organic P fractions was negatively related to phosphatase activities in the top 5 cm. Conclusion We conclude that input of P by litter decomposition and potential soil extracellular phosphatase activity are the two main factors related to seasonal soil P fluctuations, and therefore the P economy in P impoverished soils. Organic soil P followed a clear seasonal pattern, indicating tight cycling of the nutrient, while reinforcing the importance of studying soil P as an integrated dynamic system in a tropical forest context.
110. 题目: Soil bacteria respond to regional edapho-climatic conditions while soil fungi respond to management intensity in grasslands along a European transect
期刊: Applied Soil Ecology
作者: A. Barreiro, A. Fox, M. Jongen, J. Melo, M. Musyoki, A. Vieira, J. Zimmermann, G. Carlsson, C. Cruz, A. Lüscher, F. Rasche, L. Silva, F. Widmer, L.M. Dimitrova Mårtensson
摘要: Soil microbial community structure is determined by environmental conditions and influenced by other factors, such as the intensity of the land use management. Studies addressing the effect of environmental factors and management on grassland soil microbial communities at the continental scale are missing, and the wide range of ecosystem services provided by these ecosystems are thus also wanting. To address this knowledge gap, this study presents data on grassland soil microbial communities along a pan-European agro-ecological gradient. The transect included five geographical locations (Sweden, Germany, Switzerland, Portugal mainland, Portugal Azores). At each location, soils were collected in two regions characterized by favourable and less favourable conditions for plant growth. In each of these ten regions, grasslands along a gradient of management intensity were selected, i.e. grassland under intensive, less intensive and extensive management. Phospholipid fatty acid analysis (PLFA) was used to characterize the microbial community structure (PLFA pattern) in relation to climatic and soil properties. Over the whole geographical range, the environmental properties determined the soil microbial community structure. In Sweden and Switzerland, the regional growth conditions had the strongest influence on the soil microbial communities, while in Germany, Portugal mainland and Azores the management intensity was more important. Splitting up this whole community response into individual groups reveals that, in general, saprotrophic fungal biomarkers were highest in extensively managed grasslands while bacterial biomarkers differed mainly between the regions. We conclude that at the transect level, climate and soil properties were the most important factors influencing soil bacterial community structure, while soil fungal groups were more responsive to grassland management intensity. Overall agricultural sustainability could benefit from informed soil health promoting management practices, and this study contributes to such knowledge, showing the importance of management for the soil microbial biomass and community structure.
111. 题目: Impact of sustainable land‐use management practices on soil carbon storage and soil quality in the Goa state of India
期刊: Land Degradation & Development
作者: Venkatesh Paramesh, Surendra Kumar Singh, Deepak S. Mohekar, Vadivel Arunachalam, Shiva Dhar Misra, Shankar Lal Jat, Parveen Kumar, Arun Jyoti Nath, Nirmal Kumar, Gopal Ramdas Mahajan, Tejasvi Bhagat
摘要: Evaluating sustainable land management (SLM) practices has regional to worldwide implications. It is imperative to develop SLM under particular soil type, climate, and cropping sequence following area-specific best management practices to harness maximum profitability. The alternative land-use system (ALUS-natural forest, pasture, cashew, areca nut, coconut) on hills and agricultural land-use system (AGLUS-rice-rice, rice-pulse) in the coastal plains of Goa state in west coast India were evaluated in this study. The present study assessed the impact of sustainable land-use management practices on different fractions of soil organic carbon (SOC), its stock and soil quality index (SQI) under ALUS and AGLUS. The total SOC stocks under different land-use systems varied from 14.4 Mg C ha−1 in rice–rice rotations to 133.7 Mg C ha−1 in cashew. The lability index, available nutrients, and biochemical properties were higher in ALUS. The variation in the levels of SOC and soil quality was due to land use and management practices. The results indicated land use with areca nut (SQI=0.8) on the hills and rice–pulses (SQI=0.25) rotations on the coast had maintained soil quality of high order. We recommend promoting sustainable agriculture with ALUS on the hills and AGLUS on the coastal plains of Goa state to enhance SOC storage, improve soil quality, and increase farmers' income.
112. 题目: The spatial variations of water quality and effects of water landscape in Baiyangdian Lake, North China
期刊: Environmental Science and Pollution Research
作者: Liqing Li, Xinghong Chen, Meiyi Zhang, Weijun Zhang, Dongsheng Wang, Hongjie Wang
摘要: Baiyangdian Lake (BYD), a large shallow lake in North China, has complex water landscape patterns that are underlies spatial variations in water quality. In this study, we collected 61 water samples from three water landscapes (reed littoral zones, fish ponds, and open water) and analyzed them for water quality parameters, such as dissolved organic carbon (DOC), total nitrogen (TN), and total phosphorus (TP). Water landscape distribution (determined using remote sensing imagery) was then used to assess correlations between water quality parameters and water landscape proportion in differently scaled buffer zones. There was substantial variation across all subareas, with TN and TP concentrations ranging from 0.90 to 4.10 mg/L and 0.06 to 0.18 mg/L, respectively, in class IV of water quality as a whole. Spatial variations in water quality were mainly caused by water landscape distribution and external nutrient inputs. There were negative correlations between DOC, TN, and TP concentrations and the area proportion of reed littoral zones in the 300 and 500 m buffers. In contrast, DOC, TN, and TP concentrations were significantly positively correlated with the area proportion of fish ponds in the 100 m buffer. Furthermore, compared with reed littoral zones, a lower ratio of nitrogen to phosphorus and a higher proportion of dissolved organic nitrogen and tyrosine-like proteins were found in fish ponds. These effects were mainly attributed to the development of internal sediment loadings due to nutrient exchange across the sediment–water interface. Therefore, dredging-based sediment removal from fish ponds should be considered to suppress internal phosphorus loading and accelerate recovery of the BYD ecosystem.
113. 题目: Phosphorus geochemical forms and potential bioavailability in surface sediments from Edku Lagoon, Egypt, regarding diagnostic ratios (Fe:P, S:Fe, and OC:OP)
期刊: Journal of Soils and Sediments
作者: Mohamed A. Okbah, Gehan M. El Zokm, Ghada F. El-Said, Mona Kh. Khalil
摘要: Purpose Sediments play an important role in the nutrient dynamics of shallow lakes. In this work, the geochemical characterization of phosphorus (P) in the surface sediments of Edku Lagoon, Egypt, was studied in Spring 2019. Spatial variation, geochemical forms of P, and the factors affecting them were discussed. The concentrations of four operationally determined bioavailable P fractions that can be extracted from the sediments were examined. These fractions were water-soluble P (WSP, F1), readily desorbable P (RDP, F2), algae-available P (AAP, F3), and NaHCO3-extractable P (Olsen P, F4). Materials and methods Thirteen surface sediment samples were collected from Edku Lagoon, and from feeder drains. Sediment geochemical properties, total P (TP), inorganic P (IP), organic P (OP), bioavailable P fractions, and diagnostic ratios (Fe:P, S:Fe, and OC:OP) were determined. The results were discussed through various statistical analyses. Results and discussion The ranges and relative percentages of these P forms of the total concentration in the lagoon sediment stations examined were in the following order: AAP (16.7–35.4; 25.7 ± 6.65%) > Olsen P (9.1–13.8; 11.3 ± 1.74%) > WSP (2.7–8.2; 6.0 ± 1.96%) > RDP (0.41–1.26; 0.89 ± 0.32%). The results showed that IP was the main form of TP in the sediments; its concentration was six times that of OP. The relative IP to TP ratio ranged between 69 and 98%, whereas OP accounted for 2–31% of TP. The sediments of Edku Lagoon were characterized by relatively large amounts of bioavailable P; the sum of P fractions exceeded 40% of the TP. The severe increase in AAP indicated very abundant vegetation. The diagnostic ratios (Fe:P, S:Fe, and OC:OP) were calculated. Most stations had Fe:P < 15 (high P internal loading). However, 85% of the studied sediment samples had S:Fe < 1.5 ratios, which showed high sediment potency to isolate Fe-associated P forms. The high OC:OP ratio along the studied lagoon and drains reflected the hypertrophic conditions and foreign input sources of organic carbon. Conclusions The results reflected the ability of the studied P fractions to release easily from the lagoon sediments, which contributes greatly to the abundance of P from the sediments and its ease of access to surface waters, and therefore the sediments must be dredged in Edku Lagoon. The information collected will be useful in the management and development of the examined lagoon.
114. 题目: Dissolved free amino acids and polyamines are two major dissolved organic nitrogen sources for marine bacterioplankton in the northern slope of the South China Sea
作者: Qian Liu, Ye Lu, Jun Xu, Zhuo-Yi Zhu, Yeping Yuan, Wen-Chao Ma, Yurong Qian, Chun-Sheng Wang, Xue-Wei Xu
摘要: The northern slope water of the South China Sea (SCS) is oligotrophic. The regenerated nitrogen from dissolved organic nitrogen (DON) has been suggested to play a pivotal role in sustaining primary productivity; however, DON cycling has not been investigated there. Dissolved free amino acids (DFAAs) and polyamines (DFPAs) are two major groups of labile DON that are used rapidly by heterotrophic bacteria, and important in nitrogen cycling. Here, we measured turnover rates and concentrations of representative DFAAs (arginine and glutamic acid) and DFPAs (putrescine) in waters of the northern slope of the SCS, to estimate uptake rates and evaluate their potentials to fulfill carbon and nitrogen demands of bacterial production. Furthermore, homologs of genes encoding transporter systems for arginine (aotJ) and putrescine (potD/potF) were quantified in metagenomes from four depths at two sampling stations. The taxa encoding these genes were identified to gain insight into the composition of microbial communities potentially utilizing DFAAs and DFPAs. We found that uptake rates of two DFAAs and putrescine were more rapid than measured previously in seawater with similar environmental characteristics. The uptake of arginine and glutamic acids was estimated to account for 2.4-51% (19 ± 14%) and 2.7-59% (24 ± 20%) of bacterial carbon and nitrogen demand, respectively, and putrescine uptake contributed 4.4-100% (27 ± 33%) and 13-293% (80 ± 96%), respectively. Spatial variation in uptake rates indicated that biogeochemical cycling of DFAAs was distinct from that of DFPAs. Redundancy analysis and metagenomes demonstrated that environmental variables and distinction in bacterial assembleges using DFAAs and DFPAs could both affect their dynamics in the northern slope water of the SCS.
115. 题目: Preparation and evaluation of humic acid–based composite dust suppressant for coal storage and transportation
期刊: Environmental Science and Pollution Research
作者: Xiaoxiao Yu, Xiangming Hu, Weimin Cheng, Yanyun Zhao, Zhiang Shao, Di Xue, Mingyue Wu
摘要: To mitigate environmental pollution caused by the escape of dust during coal storage and transportation, humic acid (HA) and grafted acrylamide (AM) were used as raw materials to prepare a composite dust suppressant suitable for coal storage and transportation. Single-factor experiments were used to explore the optimal synthesis conditions of the dust suppressant, and the microstructure of the product was studied using Fourier-transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H-NMR), scanning electron microscopy (SEM), and other methods. The wetting effect of the dust suppressant on coal was also investigated by way of molecular dynamics (MD) simulations. The experimental results showed that the dust suppressant had good wind erosion resistance (wind erosion rate 10.2%), shock resistance (loss rate 3.63%), and anti-evaporation performance, while the MD simulation and permeability analysis results showed that the dust suppressant had an excellent wetting effect on the coal surface. SEM images revealed that the dust suppressant can fill the gaps between coal dust particles and bond them together to form a consolidated layer, thereby effectively inhibiting the escape of dust sources during coal storage and transportation.
116. 题目: Seasonal Dynamics of Surface Dissolved Organic Matter in the South China Sea and the Straits of Malacca: Implications for Biogeochemical Province Delineation of Marginal Seas
期刊: Journal of Geophysical Research: Biogeosciences
作者: Yixue Zhang, Ying Wu, Jing Zhang, Jie Jin, Jian Li, Zhenqiu Zhang
摘要: Biogeochemical provinces are an important aid to identify homogeneous biogeochemical characteristics and underlying ecosystem dynamics in the open ocean. This macroscale approach, however, does not appear to be applicable to marginal seas for disregarding various small scale changes. Here, we adopted two observation schemes throughout the typical marginal seas, the South China Sea (SCS) and Straits of Malacca (MS), with continuous surface-water sampling during March and May 2018. Spatial and seasonal heterogeneity of hydrological and dissolved organic matter (DOM) properties was investigated. With a novel combination of chromophoric DOM index and classical biogeochemical parameters (temperature, salinity, chlorophyll-a, and bathymetry), we delineated five biogeochemical provinces in each season to integrate DOM pools and investigate region-specific and season-dependent biogeochemical processes. The results showed that the SCS basin was seasonally modulated by biological activities and photodegradation, resulting in the biologically active DOM pools. The western SCS seasonally received terrestrial DOM, subjected to the western boundary current under monsoon regulation. The MS was found to serve as an efficient carbon source of terrestrial substances, which exported to the northern Indian Ocean during the Northeast Monsoon. The delineation favored the simplification of complex biogeochemistry and allowed us to predict future trends in this dynamic system. Chromophoric DOM index was proven applicable to the delineation of marginal seas, that shed the light on the potential applications in biogeochemical provinces in dynamic systems.
117. 题目: Roles of biochar in cement-based stabilization/solidification of municipal solid waste incineration fly ash
期刊: Chemical Engineering Journal
作者: Liang Chen, Lei Wang, Yuying Zhang, Shaoqin Ruan, Viktor Mechtcherine, Daniel C.W. Tsang
摘要: Low-carbon stabilization/solidification (S/S) is of increasing importance for sustainable treatment of hazardous wastes. In this study, we integrated carbon-negative rice husk biochar (RBC) and yard waste biochar (YBC) as green additives into the binder for S/S of municipal solid waste incineration (MSWI) fly ash. Experimental results illustrated that the addition of both biochars promoted cement hydration reaction via pozzolanic reaction and internal curing. In particular, the incorporation of 10 wt.% RBC (rich in activated Si) significantly increased the content of C-S-H gel from 41.6 wt.% (control sample) to 52.0 wt.% and increased the average degree of connectivity of C-S-H gel from 1.43 to 1.52 as indicated by quantitative X-ray diffraction and 29Si nuclear magnetic resonance analysis. The incorporation of RBC and YBC (20 or 30 wt.%) enhanced the immobilization efficiency of potentially toxic elements in MSWI fly ash due to the additional hydration products and high adsorption ability of biochar. For instance, in R-80FA and Y-80FA samples (namely, 20 wt.% binder dosage, of which RBC or YBC accounted for 10 wt.% of binder), the immobilization efficiency for Pb could reach 96.2% and comply with the leachability limit. The biochar-modified S/S blocks achieved comparable strength to the cement-based S/S blocks, presenting a mechanically stable solidified matrix for engineering application. Therefore, this study expands the emerging application of biochar and demonstrates that biochar-augmented binder can ensure low-carbon and high-performance S/S of hazardous materials.
118. 题目: Adsorption of metal on pineapple leaf biochar: key affecting factors, mechanism identification, and regeneration evaluation
期刊: Bioresource Technology
作者: Kesinee Iamsaard, Chih-Huang Weng, Li-Ting Yen, Jing-Hua Tzeng, Chakkrit Poonpakdee, Yao-Tung Lin
摘要: Although tremendous works have been done on metal adsorption via biochar, mechanisms responsible for metal adsorption remain uncertain. This is the first work that provides direct evidence on the identification of Ni(II), Zn(II), and Cu(II) adsorption mechanisms on pineapple leaf biochar (PLB) using surface characteristics analyses, including X-ray photoelectron spectroscope (XPS), Fourier transform infrared spectroscope (FTIR), and scanning electron microscope with energy-dispersive X-ray spectroscope (SEM-EDS). From Langmuir isotherm fitting, the maximum adsorption capacity of PLB for Ni(II), Zn(II), and Cu(II) are 44.88, 46.00, and 53.14 mg g-1, respectively, surpassing all biochars reported in the literature. Findings of surface characterization techniques coupled with cation released during adsorption, cation exchange, and surface complexation mechanisms were proposed. PLB is reusable and remains sufficient adsorption capacity even six consecutive cycles via pressure cooker regeneration. With high regenerability and ultrahigh adsorption capacity, PLB defines itself as a promising adsorbent for future applications in metal-laden wastewater.
119. 题目: Molecular characterization of the composition and transformation of dissolved organic matter during the semi-permeable membrane covered hyperthermophilic composting
期刊: Journal of Hazardous Materials
作者: Bo Sun, Yongshuang Li, Manjiao Song, Rui Li, Zaixing Li, Guoqiang Zhuang, Zhihui Bai, Xuliang Zhuang
摘要: Current knowledge of dissolved organic matter (DOM) in semi-permeable membrane-covered thermophilic compost (smHTC) is limited. Therefore, this study provided a comprehensive characterization of composition and transformation of DOM in smHTC using multiple spectroscopic methods and ultrahigh resolution mass spectrometry. The results showed that the values of SUVA280, SUVA254, A240-400 (0.042, 0.048, 34.193) in smHTC were higher than those of conventional thermophilic composting (cTC) (0.030, 0.037, 18.348), and the increment of PV,n in smHTC were 2.4 times higher than that of cTC. These results suggested that smHTC accelerated the humification process by promoting the degradation of labile DOM and the production of humus-like substances. Mass spectrometry further confirmed that the DOM of smHTC possessed higher degree of aromatization and humification, based on the lower H/C (1.14), and higher aromaticity index (0.34) and double bond equivalence (10.36). Additionally, smHTC increased the proportion of carboxyl-rich, unsaturated and aromatic compounds, and simultaneously improved the degradation of aliphatic/proteins, lipids, carbohydrates, along with even some refractory substances such as CHO subcategory (24.1%), especially lignin-like structures (14.8%). This investigation provided molecular insights into the composition and transformations of DOM in smHTC, and extended the current molecular mechanisms of humification in composting.
120. 题目: Deep dewatering of activated sludge using composite conditioners of surfactant, acid and flocculant: The mechanism and dosage model
期刊: Science of The Total Environment
作者: Xuejie He, Lei He, Ziyuan Lin, Jiong Zhou, Shuohui Shi, Yi Liu, Jian Zhou
摘要: To address the problem of difficult disposal caused by poor dewaterability of high-organic sludge in wastewater treatment plant, this study developed a sludge composite conditioner (SCC) consisting of sodium dodecyl sulfate (SDS), HCl and FeCl3. It has the potential to significantly improve the dewaterability of the high-organic sludge with the VSS/MLSS of 80%. The moisture content (MC) and bound water content of sludge were reduced from 98.00 to 59.65% and from 3.42 to 0.91 g/g dry sludge (DS) after being conditioned, respectively. The surfactant (SDS) promoted the dissolution of extracellular polymeric substances (EPS). The acid (HCl) enhanced the decomposition of the sludge flocs, making the insoluble EPS peel off and turn into the liquid phase. As a result, total EPS decreased by 52.70% compared to the original sludge. In addition, due to the neutralization effect of protons and FeCl3, the Zeta potential increased remarkably from −13.80 mV to −1.72 mV and the dispersed sludge particles formed during EPS dissolution process were re-flocculated, which increased the average size of the sludge particles. The ratio of proteins (PN)/polysaccharides (PS) also increased from 1.69 to 3.81. And a quantitative model of optimum dosage of SCC agents based on the influence of the sludge PS, PN and EPS content has been established, aiming to determine the dosage of each conditioner according to the properties of target sludge. In general, the SCC provided an effective pathway for sludge deep dewatering.