221. 题目: Enhanced propagation of intracellular and extracellular antibiotic resistance genes in municipal wastewater by microplastics
期刊: Environmental Pollution
作者: Yuan Cheng, Jiarui Lu, Shusen Fu, Shangjie Wang, Naomi Senehi, Qingbin Yuan
摘要: Microplastics (MPs) are an emerging global concern as they are abundant in the environment and can act as vectors of various contaminants. However, whether and how MPs can be vectors of antibiotic resistance genes (ARGs), especially extracellular ARGs (eARGs), remains far from explicit. This study addresses the adsorption of both intracellular ARGs (iARGs) and eARGs by four types of MPs in municipal wastewater, and then explores the potential horizontal gene transfer of iARGs and eARGs exposed to MPs. Results indicate that though MPs significantly adsorbed both iARGs and eARGs, eARGs were adsorbed with a significantly higher fold enrichment (2.0–5.0 log versus 2.0–3.3 log) and rate (0.0056 min−1 versus 0.0037 min−1) than iARGs. While all four types of MPs adsorbed ARGs, polypropylene MPs showed the highest adsorption capacity for ARGs. Background constituents such as humic acid and antibiotics significantly inhibited adsorption of iARGs, but not eARGs on MPs. The presence of sodium chloride didn't significantly affect adsorption of iARGs or eARGs. The adsorption of ARGs was well explained by the extended Derjaguin–Landau–Verwey–Overbeek (XDLVO) interaction energy profile. Higher eARG adsorption was attributed to a lower energy barrier between MPs and eARGs than that between MPs and iARGs. Exposure to MPs enhanced horizontal gene transfer of both iARGs and eARGs by 1.5 and 2.0 times, respectively. The improved contact potential between donors and recipients, as well as the increased cell permeability of recipients induced the improved horizontal gene transfer by MPs. This study underscores the need to address ARG propagation through adsorption to MPs.
222. 题目: Site-specific modelling of short-term soil carbon mineralization in central Argentina
作者: Julius Koritschoner, Franca Giannini Kurina, Susana Hang, Mónica Balzarini
摘要: Soil organic carbon (SOC) mineralization is essential for nutrient cycling; however, it also increases carbon emission as CO2 to the atmosphere (CO2-C). Therefore, detailed information is required to design land use practices promoting positive C balances and soil health. Short-term SOC mineralization is sensitive to soil properties. Short-term soil C mineralization at a landscape scale has been poorly describe, despite the need to understand the variability of C dynamics among environments. The objectives of this work were to 1) estimate the parameters of short-term soil C mineralization kinetics in different locations within a region and 2) explore correlations among site-specific kinetic parameters and edaphoclimatic properties of sampled sites. The study involved 150 sites with different soil and climatic characteristics sampled from a 165,000 km2 area in central Argentina. CO2-C data were obtained from 28-day laboratory incubation experiments of the 150 soil samples. We tested three models (exponential, hyperbolic and power), which depend non-linearly on their parameters, to describe the population average cumulative CO2-C. Using nonlinear mixed models, we tested the significance of random site effects to explain variability in curve parameters among soils. Random forest was used to explain C mineralization parameters from edaphoclimatic properties. The best fit was provided by the power model with random effects on two parameters: initial C mineralization rate and mineralization rate coefficient. The results indicate heterogeneous C mineralization processes across central Argentina. The observed cumulative CO2-C after 28 days of soil incubation ranged between 250 and 1693 mg C kg−1 soil with an average of 826 mg C kg soil−1. Lower amounts of CO2-C (800 mg C kg−1 soil) are expected at 28 days of mineralization in sandy loam soils with lower organic matter than in rich loam soils (more than 1000 mg C kg−1 soil). A relational study explaining site-specific C mineralization from soil, climatic and management variables indicated a significantly higher short-term C mineralization in soils with high organic matter and soil chemical fertility, with soil properties being more important process drivers than climatic variables. Thus, short-term C mineralization kinetics can be predicted from soil properties at the large scale.
223. 题目: Different mechanisms driving the preferential adsorption of dissolved organic matter by goethite and montmorillonite
期刊: Chemical Geology
作者: Lanfang Han, Yan Yang, Ke Sun, Biao Zhang, Yalan Chen, Liping Fang, Baoshan Xing
Molecular fractionation of dissolved organic matter (DOM) at the mineral-water interface governs its role in biogeochemical processes in both terrestrial and aquatic environments. However, adsorptive fractionation of DOM onto phyllosilicates lacks molecular-scale investigation. Moreover, the mechanisms driving DOM adsorptive fractionation onto typical mineral surface remains unknown. Using ultra-high resolution mass spectrometry, traditional spectroscopic method, and different background electrolytes (CaCl2, NaCl and NaCl-NaH2PO4), we investigated the molecular fractionation of DOM by typical phyllosilicate (montmorillonite) and iron oxyhydroxide (goethite) and provided direct and quantitative evidence for the specific driving mechanisms for the adsorptive fractionation. Montmorillonite selectively adsorbed the comparatively low molecular weight (MW) and high O/C constituents having aliphatic moieties (mainly protein- and carbohydrate-like species) or one benzene ring as first identified using a new aromaticity equivalent. This structural preference was more remarkable in the adsorption system with large contribution of “Ca2+ bridging” reaction (45.6–76.0%). By contrast, goethite preferentially stabilized the constituents with high MW components containing aromatics with ≥3 condensed benzene rings and high O/C, which was notable in the system where “ligand exchange” mechanism predominated (55.5–71.4%). For both montmorillonite and goethite, non-selective adsorption of DOM was detected when van der Waals dominated. These findings would advance the mechanistic understanding of biogeochemical processes of DOM in the environments.
224. 题目: Molecular Investigation on Changing Behaviors of Natural Organic Matter by Coagulation with Non-Targeting Screen Using High-Resolution Mass Spectrometry
期刊: Journal of Hazardous Materials
作者: Gefei Ma, Hui Xu, Xiaofang Yang, Guangyu An, Qinxue Yang, Xi Wang, Dongsheng Wang
摘要: Natural organic matter (NOM) can tremendously influence the purification efficiency of the drinking water treatment process. Coagulation was the first and primary process of NOM removal in the drinking water treatment process. The interaction between coagulants and NOM molecules remains unclear. Three typical coagulants (Al13, FeCl3, and AlCl3) were used to investigate the effects on NOM removal. The measurement of NOM was conducted using 15T Electrospray Ionization coupled Fourier-Transform-Ion Cyclotron Resonance Mass Spectrometry (ESI-FT-ICR MS). The coagulation process altered the mass peak numbers as well as relative intensity of the peaks which were positively correlated with TOC value. The lignin-like compound was the most abundant moiety in raw water. Al-based coagulants remove more unsaturated larger compounds (lower KMD and higher carbon number). Al13 remove the unsaturated hydrocarbons preferably. FeCl3 is more reactive with NOM molecules and removes more fully saturated compounds. These findings revealed the coagulation removal mechanism of NOM with different structural characteristics and advise the practical use of coagulants for various raw water with different NOM characteristics.
225. 题目: Spatial variation of organic carbon sequestration in large lakes and implications for carbon stock quantification
作者: Qi Lin, Enfeng Liu, Enlou Zhang, Richard Bindler, Bibhash Nath, Ke Zhang, Ji Shen
摘要: Lakes are recognized as critical zones for carbon transformation and storage, and lacustrine sediments sequestrate considerable amounts of organic carbon (OC). Understanding sedimentation processes and OC burial patterns is crucial to clarifying lakes’ role in global carbon cycling. However, OC sedimentation may be quite spatially heterogeneous within an aquatic system, owing to the differences in OC production and sources, hydrodynamic conditions and underwater topography. The uncertainties in estimating OC sequestration in the world’s large lakes remain poorly constrained. This study takes the test case of two large lakes (50 and 249 km2) with different water depth and trophic status, using a multi-core paleolimnological technique, to identify the spatial variation in OC accumulation and its main influencing factors over the past century. Results of multi-core comparisons revealed similar temporal trends in major organic and nutrient parameters, suggesting coherent processes of whole-lake sedimentary environment changes for each lake. The OC preserved in sediments was primarily of autochthonous origin. However, OC standing stocks varied ∼3-fold spatially, and average OC accumulation rates ranged between 9.5–27.4 g m−2 yr−1 (post–1963 in oligo-mesotrophic deep-lake Lugu) and between 17.4–43.5 g m−2 yr−1 (post–1980 in eutrophic shallow-lake Erhai), respectively. These variations were primarily attributable to the spatial differences in aquatic primary production and terrestrial detritus supply relating to anthropogenic land-use change and phosphorus loading, rather than intra-lake sediment focusing-related transport and redistribution. The single central-core approach from Lugu Lake would overestimate whole-lake OC stock by 32% or underestimate the value by 48%, indicating spatial variability is an important source of uncertainty for OC stock quantification in similar large and/or morphometrically complex waterbodies. Therefore, spatial heterogeneity of OC accumulation in inland waters requires considerable research with well-placed multi-cores to provide a deeper understanding of carbon sequestration patterns and mechanisms.
226. 题目: Connectivity and pore accessibility in models of soil carbon cycling
期刊: Global Change Biology
作者: Philippe C Baveye, María Balseiro Romero, Valérie Pot, José Julio Ortega‐Calvo
摘要: In an article published recently, Waring et al. (2020) introduced a conceptual framework, named PROMISE, to explore controls on belowground carbon cycling. This “fundamentally novel approach to measuring and modeling critical carbon cycle processes” represents soil pore space as an array of possible particle locations belonging to one of three pore size classes. Several aspects of this conceptual framework raise questions about its adequacy to describe the fate of carbon in heterogeneous soils. More than a decade ago already, Kuka et al. (2007) advocated the significance of the size of pores when modeling carbon turnover in soils and proposed a model, called CIPS (“Carbon Turnover in Pore Space”), which is not mentioned by Waring et al. (2020) even though in several respects, CIPS is very similar to PROMISE, and shares the same aims and approach. In CIPS, pores are also divided into three classes according to their size. Like PROMISE, CIPS does not assume any spatial arrangement, distance, or differences in connectivity among the three classes of pores. The neglect of pore connectivity may have been a defensible working hypothesis in 2007. However, experimental research as well as a sizeable amount of modeling work (reviewed in Baveye et al., 2018) has since demonstrated the importance of the connectivity, size, and degree of water saturation of pores on a wide range of soil processes, including the decomposition of soil OM. PROMISE makes a small provision for the importance of pore connectivity by assuming that the probability of a particle leaving a pore of any size depends on whether the soil is dry or moist. However, this is a very crude way to take pore connectivity into account. Another set of questionable assumptions of PROMISE concerns the probabilities of particles entering and leaving mesopores, associated with clay domains, or micropores, between individual clay platelets. Waring et al. (2020) assume a priori, without any experimental data at this stage to support it, that the probability of a monomer leaving an intraparticle pore is 200 times less than its probability of penetrating it. From that perspective, one expects that organic matter that manages to diffuse in those tiny pores remains there for extended periods of time. However, this sequestration, if it occurs at all, cannot be due to diffusion alone, without the involvement of some other process that may need to be modeled explicitly. Indeed, Dumestre et al. (2000, 2006), using Electron Paramagnetic Resonance spectroscopy to monitor the behavior of spin probes, have shown experimentally that probe molecules that had entered intraparticle pores in a suspension of bentonite clay particles could relatively easily diffuse out if a chemical reaction or consumption by bacteria, outside of the pores, decreased the concentration of spin molecules in the bulk solution. In that context, a possible alternative to pore exiguity as an explanation for the persistence of organic matter is that, because of low connectivity and high tortuosity of the pore space in soils, neither microorganisms nor even their exoenzymes can get close enough to the organic matter to prompt it to diffuse out in the open. Another issue concerning PROMISE relates to the usefulness of a computer model that contains many parameters that can be evaluated only by fitting. In PROMISE, in addition to the uncertain probabilities of particles entering and leaving pores, the volumes associated with two of the classes of pores are also virtually impossible to determine at the moment other than via parameter fitting. Indeed, only the larger “macropores” would be detectable by X-ray computed tomography, unless one worked with exceedingly small soil samples, which creates challenges of its own, in terms of the representativeness of measurements and their upscaling to larger volumes. Mercury intrusion porosimetry could in principle be used to determine the pore size distribution down to diameters of the order of 3 nm. Unfortunately, this method suffers from a potentially severe overestimation of the volume of small pores due to connectivity-related ink-bottle and sample size effects (Moro and Böhni, 2002). Perhaps to avoid these problems, Waring et al. (2020) did not attempt to measure the volume of pore classes, but assumed instead that “the distribution of different pore size classes can be related to soil texture and mineralogy.” However, soil texture and mineralogy are typically evaluated after heavy disturbance of the architecture of soils, and may therefore not be at all correlated in a straightforward manner with the pore size distribution in the original, undisturbed soil. Before significantly more time and effort are invested in the development of the PROMISE model, it would be worth investigating the extent to which some of its key premises are sound, and in particular whether it is feasible to describe the dynamics of processes occurring in soils without taking at all into account the connectivity of their pore space.
227. 题目: Evolution of Atmospheric Total Organic Carbon from Petrochemical Mixtures
期刊: Environmental Science & Technology
作者: Kun Li, Jeremy J B Wentzell, Qifan Liu, Amy Leithead, Samar G Moussa, Michael J Wheeler, Chong Han, Patrick Lee, Shao-Meng Li, John Liggio
摘要: Reactive organic compounds play a central role in the formation of ozone and secondary organic aerosols. The ability to accurately predict their fate, in part, relies upon quantitative knowledge of the chemical and physical parameters associated with the total organic carbon (TOC), which includes both precursors and oxidation products that evolve in the atmosphere over short to long time scales. However, such knowledge, obtained via limited carbon closure experiments, has not been attained for complex anthropogenic emissions. Here we present the first comprehensive characterization of TOC in the atmospheric oxidation of organic vapors from light and heavy oil mixtures associated with oil sand operations. Despite the complexity of the investigated oil mixtures, we are able to achieve carbon closure (83–116%) within the uncertainties (±20%), with the degree of the closure being dependent upon the vapor composition and NOx levels. In contrast to biogenic precursors (e.g., α-pinene), the photochemical time scale required for a largely complete oxidation and evolution of chemical parameters is very long for the petrochemical vapors (i.e., ∼7–10 days vs ∼1 day), likely due to the lower initial precursor reactivity. This suggests that petrochemical emissions and their impacts are likely to extend further spatially than biogenic emissions, and retain more of their complex composition and reactivity for many days. The results of this work provide key parameters to regional models for further improving the representation of the chemical evolution of petrochemical emissions.
228. 题目: Testing the effects of coastal culture on particulate organic matter using absorption and fluorescence spectroscopy
期刊: Journal of Cleaner Production
作者: Jiajun Lei, Liyang Yang, Zhuoyi Zhu
摘要: Aquaculture is a major type of human activity that disturbs the biogeochemistry and ecosystem in coastal environments, yet its influence on the optical properties of particulate organic matter remains largely unknown. This was studied for the Aojiang Estuary-cultural zone-adjacent seawater continuum in SE China in July and October 2019, and in January 2020, using absorption spectroscopy and fluorescence excitation-emission matrices-parallel factor analysis (EEMs-PARAFAC). The POM absorption, three humic-like components (C1, C2, and C5), and humification index (HIX) generally decreased from the river to the seawater and were higher in October than in January. The humic substances were mainly derived from terrestrial sources and sediment resuspension, which were dependent largely on the level of total suspended matter (r: 0.823–0.888). The intensity of shoulder peak in the absorption spectra and the tryptophan-like C4 were lower in the river than in seawater in July, which was in contrast to the spatial distribution in other months. They correlated positively with Chl a (r: 0.779–0.912), indicating they were mainly related to the algal production. Principal component analysis (PCA) revealed notable seasonal variations of POM with an elevated autochthonous contribution in July, indicating stronger algal production than the removal by shellfish. The low autochthonous POM in October and January identified with PCA suggested limited addition from the laver culture after the shellfish harvest. The mooring monitoring in July and October further demonstrated that the POM in the cultural zone and adjacent seawater was influenced by the active material exchange across the continuum, strong tides, sediment resuspension, algal production, and microbial transformation. Our results have implications for assessing the influences of aquaculture activities on the water quality and ecosystem in the coastal environments.
229. 题目: Soil organic carbon content and mineralization controlled by the composition, origin and molecular diversity of organic matter: A study in tropical alpine grasslands
期刊: Soil and Tillage Research
作者: Songyu Yang, Boris Jansen, Samira Absalah, Karsten Kalbitz, Fresia O. Chunga Castro, Erik L.H. Cammeraat
摘要: The consensus for mechanisms controlling soil organic matter (SOM) persistence has shifted from traditional views based on SOM recalcitrance to a new paradigm based on SOM stabilization controlled by soil minerals and aggregates. Recent studies indicate that the origin, composition and molecular diversity of SOM are crucial to the decomposition and stabilization of SOM. However, it is not fully understood how the decomposition and stabilization of SOM are controlled at the molecular level. The objectives of this study were to investigate whether soil organic carbon (SOC) contents and mineralization are controlled by the composition, origin and molecular diversity of SOM. Soil samples were collected from contrasting bedrocks with different precipitation levels at tropical alpine grasslands of the Peruvian Andes. We applied a combination of a 76-day soil incubation experiment and pyrolysis-GC/MS assisted by thermochemolysis to investigate SOM decomposition and stabilization at the molecular level. The results indicated that soil samples with high SOC contents (92.6 ± 7.6 g kg−1 soil) and low SOC mineralization had abundant derivates of lignin, polysaccharides and n-alkanes. After the incubation, we observed neither a selective decomposition of any compound groups nor a decline of molecular diversity. In contrast, soil samples with low SOC contents (30.7 ± 2.8 g kg−1 soil) and higher SOC mineralization showed a depletion of plant-derived compounds, an accumulation of microbial-derived compounds and declined molecular diversity after the incubation. Furthermore, the SOC mineralization of these samples was positively correlated to the depletion of unsaturated fatty acids and the decrease in molecular diversity after the incubation. Therefore, we proposed that SOC contents and mineralization in our soils are (1) controlled by selective preservation of SOM molecular groups (e.g. plant-derived compounds), and (2) associated with changes in molecular diversity of SOM during microbial decomposition. Due to the selective preservation of organic compounds under different environmental conditions, we propose that environmental factors should be considered for the management of ecosystem services such as SOC sequestration in the studied region.
230. 题目: Effect of dissolved organic matter on the phytoremediation of Cd-contaminated soil by cotton
期刊: Ecotoxicology and Environmental Safety
作者: Tao Min, Tong Luo, Lili Chen, Weidan Lu, Yan Wang, Liyang Cheng, Sibo Ru, Junhua Li
摘要: Dissolved organic matter (DOM) assists in the phytoremediation of heavy-metal-contaminated soils, but the effect of synergistic remediation of DOM on plants is unclear. This study investigated the effect of two DOM sources (cotton straw (CM) DOM and farmyard manure (FM) DOM) on cadmium (Cd) accumulation in Cd-contaminated soil by cotton and evaluated the phytoremediation effect of DOM. The results showed that adding DOM reduced the available nitrogen and increased organic matter, available phosphorus and available potassium. Applying DOM increased the proportions of Cd acid soluble fractions and reduced the proportions of Cd residual fractions by 1–7%. DOM application increased root length, root surface area and root volume compared to the control and had a promoting or inhibiting effect on cotton biomass, depending on the soil Cd concentration. Furthermore, applying DOM improved the Cd content and bioconcentration factor of cotton. The lower the molecular weight, hydrophilic components and aromaticity of DOM, the more conducive to Cd accumulation is in cotton. The correlation and random forest analyses also showed that CM showed high remediation potential. According to our study, DOM can improve the phytoremediation efficiency of cotton, especially in low-concentration contaminated soils. This study provides a basis for applying DOM in the phytoremediation of Cd-contaminated soils.
231. 题目: Seasonal and Spatial Variability of Dissolved Carbon Concentration and Composition in Lake Michigan Tributaries
期刊: Journal of Geophysical Research: Biogeosciences
作者: Stephanie M Berg, Robert J Mooney, Megan B McConville, Peter B McIntyre, Christina K Remucal
摘要: Dissolved organic matter (DOM) is a complex mixture of many compounds, and its composition dictates numerous reactions in the environment. Large lakes and marine coastlines receive DOM from watersheds that differ widely in their land cover, with potential implications for both the quantity and composition of carbon inputs. Seasonal variation in DOM quantity and composition may also differ among tributaries and be mediated by land cover. Here, we quantify spatial (i.e., among tributary) and seasonal variation in DOM concentration, DOM composition based on ultraviolet-visible spectroscopy, and alkalinity across 101 tributaries of Lake Michigan, one of the world’s largest lakes, using a synoptic sampling approach. Wetland land cover has the largest effect on DOM, producing high concentrations of DOM that is more aromatic and larger in apparent molecular weight. Seasonal variation is also pronounced, with concentrations and aromaticity of DOM peaking in fall across most tributaries. Watershed lithology and land cover both affect alkalinity, with higher values associated with the geography of carbonate bedrock and in urbanized watersheds. Watershed land cover has a larger affect than season on all organic carbon parameters. However, seasonal variation is especially important for DOM composition. This disparity suggests that environmental processing of DOM within river channels mediates its composition more than its concentrations. Considering the wide range of land cover and lithology around Lake Michigan and other large water bodies, accounting for both spatial and seasonal dynamics is essential for understanding controls on DOM delivery.
232. 题目: Effects of forest conversion to rubber plantation and of replanting rubber trees on soil organic carbon pools in a tropical moist climate zone
期刊: Agriculture, Ecosystems & Environment
作者: Jumpei Toriyama, Akihiro Imaya, Keizo Hirai, Tiva Khan Lim, Mao Hak, Yoshiyuki Kiyono
摘要: In the past two decades, conversion of forests to rubber (Hevea brasiliensis) plantations has spread widely in continental Southeast Asia. In addition to the effect of the establishment of new rubber plantations, the impact of the replanting of rubber trees, i.e., second-rotation plantation establishment, on the soil organic carbon (SOC) pool is unknown because of the short history of land management at such sites. We examined whether the first-rotation rubber plantation (RUB_1st) soils have more of a legacy effect from previous natural forests than the second-rotation plantation soils in Cambodia, so as to improve SOC stock estimates for a series of land use changes in a tropical moist climate zone, e.g., the lowlands of continental Southeast Asia. The total SOC stock, estimated for soil masses equivalent to 0–30 cm depth, was larger in natural forest (FOR) plots (52.7 MgC ha−1) than in RUB_1st (38.4 MgC ha−1), early-stage second-rotation plantation (RUB_2nd_A1–6; tree age ≤6 years; 37.2 MgC ha−1), and middle-stage second-rotation plantation (tree age >6 years; 33.9 MgC ha−1) plots. Values for factors related to SOC dynamics, such as the mass and carbon/nitrogen (C/N) ratio of leaf litter, soil C/N ratio, soil aluminum content, and bulk density of coarse plant residue (>2 mm), were also higher in FORs than in the rubber plantations. The SOC pools in both high- and low-density fractions of topsoil were lost largely within the first 10 years of forest–rubber plantation conversion. The loss of SOC in the low-density fraction in the RUB_1st might have been compensated to some extent by the remaining plant residue in these former forests. Although weeding resulted in the mixing of temporarily growing C4 grasses with soil in RUB_2nd_A1–6 plots, these grasses might have contributed minimally to the SOC pool in the long term, as reflected by C stable isotope ratios. Accordingly, we presented a conversion factor of SOC stock as 0.66 ± 0.18 for the 9-year transition period from forests to rubber plantations on a flat topography in a tropical moist climate zone of continental Southeast Asia, and concluded that the replanting of old rubber plantations should take priority over the forest-rubber plantation conversion as possible to reduce the emission of greenhouse gas under the land use change.
233. 题目: Long‐term (64‐years) annual burning lessened soil organic carbon and nitrogen content in a humid subtropical grassland
期刊: Global Change Biology
作者: Khatab Abdalla, Pauline Chivenge, Philippe Ciais, Vincent Chaplot
摘要: Burning has commonly been used to increase forage production and nutrients cycling in grasslands. However, its long-term effects on soil organic carbon (SOC) and nitrogen (N) pools within the aggregates and the relation between aggregates-associated SOC and soil CO2 emissions needs further appraisal. This study evaluated the effects of 64-years of annual burning on SOC and N dynamics compared to annual mowing and undisturbed treatments in a grassland experiment established in 1950. Soils were sampled from four depths representing the upper 30 cm layer and fractionated into; macroaggregates, microaggregates, and silt+clay fractions. The macroaggregates were further fractionated into three occluded fractions. The SOC in the bulk soil and aggregates were correlated to soil CO2 effluxes measured under field conditions. Compared to the undisturbed treatment, annual burning decreased aggregates stability, SOC and N in the upper 30 cm layer by 8, 5 and 12%, respectively. Grassland mowing induced greater aggregates stability than burning only in the upper 5 cm. Burning also decreased SOC in the large macroaggregates (e.g., 0–5 cm) compared to mowing and the undisturbed grasslands but proportionally increased the microaggregates and their associated SOC. Soil N associated with aggregates decreased largely following grassland burning, e.g., by 8.8–fold in the microaggregates within the large macroaggregates at 20–30 cm compared to the undisturbed grassland. Burning also increased soil CO2 emissions by 33 and 16% compared to undisturbed and mowing, respectively. The combustion of fresh C and soil organic matter by fire is likely responsible for the low soil aggregation, high SOC and N losses under burned grassland. These results suggested a direct link between grass burning and SOC losses, a key component for escalating climate change severity. Therefore, less frequent burning or a rotation of burning and mowing should be investigated for sustainable grasslands management.
234. 题目: Adsorptive removal of metformin on specially designed algae-lignocellulosic biochar mix and techno-economic feasibility assessment
期刊: Environmental Pollution
作者: Goldy De Bhowmick, Rowena M Briones, Sören Thiele-Bruhn, Ramkrishna Sen, Ajit K Sarmah
摘要: Batch sorption of metformin hydrochloride (MET) onto a specially designed biochar mix consisting of both macro (MAC) and micro (MIC) algae, rice husk and pine sawdust was conducted. Pyrolysis of both MAC and MIC algae mixture was done followed by chemical activation with hydrogen-peroxide. Additionally, sorption of MET under the influence of pH was separately investigated. Batch studies of isotherms were well described by Freundlich model with high non-linearity and Freundlich exponent values ranged anywhere from 0.12 to 1.54. Heterogeneity of MET adsorption to the bonding sites was attributed to the surface functional groups of the modified biochar. Amongst the four biochars, the activated macroalgae biochar (MACAC) and microalgae biochar (MICAC) depicted favourable adsorption of MET with maximum adsorption at pH 7. Up to 76% of MET removal from the environment was obatained using the MACAC biochar. Scanning electron micrographs coupled with energy dispersive X-ray, as well as elemental analyses confirmed formation of oxygen containing surface functional groups due to activation strengthening chemisorption as the main sorption mechanism. Further, Fourier transform infra-red spectroscopy and other surface functional group analyses along with Zeta potential measurements reinforced our proposed sorption mechanism. Lowest zeta potential observed at pH 7 enhanced the electrostatic force of attraction for both the biochars. Negative zeta potential value of the biochars under different pH indicated potential of the biochars to adsorb other positively charged contaminants. From a techno-economic perspective, capital expenditure cost is not readily available, however, it is envisaged that production of pyrolyzed biochar from algal biomass could make the process economically attractive especially when the biochar could be utilised for high-end applications.
235. 题目: Potential of developing podzolic soil-based potting media from wood ash, paper sludge and biochar
期刊: Journal of Environmental Management
作者: Muhammad M Farhain, Mumtaz Cheema, Yeukai Katanda, Muhammad Nadeem, Bilal Javed, Raymond Thomas, Ratnajit Saha, Lakshman Galagedara
摘要: Background and objectives Organic waste management in environmentally sustainable way is important not only to reduce the negative impacts on ecosystems but also valorizing the waste resources. Herein we evaluated the potential of wood ash (WA) and paper sludge (PS) wastes from a pulp and paper mill as potting media and their effects on the physicochemical properties of podzolic soil. Methods WA, PS and biochar (BC) was mixed in different combinations with a sandy loam podzolic soil. Potting media treatments included: T1–soil (negative control); T2–PromixTM (positive control); T3–50%soil+50%WA; T4–75%soil+25%WA; T5–50%soil+50%PS; T6–75%soil+25%PS; T7–75%soil+25%BC; T8–25%soil+50%WA+25%BC; T9–50%soil+25%WA+25%BC; T10–25%soil+50%PS+25%BC; T11–50%soil+25%PS+25%BC, T12– 25%soil+25%WA+25%PS+25%BC and replicated three times. Results Potting media treatments expressed significant (p < 0.00) effects on pH, bulk density, total porosity, field capacity, plant available water (PAW) and water retention curves. Potting media amended with WA showed high pH range (8–12) while PS amendments exhibited pH in range where most plant nutrients are available (6.5–7.5). Results depicted significantly lower bulk density, and increased total porosity and water holding capacity of potting media amended with WA and PS. BC addition further enhanced the water retention properties compared to combinations without BC. T6, T10 and T11 produced higher amounts of PAW with desired pH compared to T1 and T2. Conclusion WA, PS and BC showed high potential for developing podzolic soil-based potting media, but their effects on plant growth and elemental uptake need to be investigated.
236. 题目: Influence of augmentation of biochar during anaerobic co-digestion of Chlorella vulgaris and cellulose
期刊: Bioresource Technology
作者: Jessica Quintana-Najera, A John Blacker, Louise A Fletcher, Andrew B Ross
The anaerobic co-digestion (AcoD) of microalgae is a prospective option for generating biomethane from renewable sources. This study investigates the effects of inoculum-to-substrate ratio (ISR), C/N ratio and biochar (BC) load on the AcoD of Chlorella vulgaris and cellulose. An initial augmentation of BC at ISR 0.5-0.9 and C/N ratio 10-30 offered a pH buffering effect and resulted in biomethane yields of 233-241 mL CH4/g VS, corresponding to 1.8-4.6 times the controls. BC addition ameliorated significantly AcoD, supporting the digestate stability at less favourable conditions. The effect of the process variables was further studied with a 23 factorial design and response optimisation. Under the design conditions, the variables had less influence over methane production. Higher ISRs and C/N ratios favoured AcoD, whereas increasing amounts of BC reduced biomethane yield but enhanced production rate. The factorial design highlighted the importance of BC-load on AcoD, establishing an optimum of 0.58 % (w/v).
237. 题目: A feasible biochar derived from biogas residue and its application in the efficient adsorption of tetracycline from an aqueous solution
期刊: Environmental Research
作者: Xiaoyu Sheng, Junkai Wang, Quantao Cui, Wei Zhang, Xinfeng Zhu
摘要: The recovery of carbon materials from biogas residue (BR) could efficiently promote the efficient utilization of waste and the preparation of novel materials. In this study, a green and feasible reagent of citric acid was introduced and applied in the modification of biogas residue biochar (BRC). The modified biogas residue biochar (CABRC) showed a superior adsorption ability due to its higher specific surface area (approximately 6 times that of the BRC). Additionally, the adsorption capacities of CABRC and BRC for TC were 58.25 mg/g and 20.77 mg/g, respectively, while the TC adsorption performance of CABRC was 2.8 times that of BRC. The adsorption of TC by both BRC and CABRC was primarily controlled by physical adsorption and chemical adsorption (including pore filling, hydrogen bonding, π−π DEA interaction, and electrostatic interaction). Therefore, CABRC should be considered an environmentally friendly material due to its higher adsorption performance, which could expand its application in wastewater treatment.
238. 题目: Cleaner production of flexographic ink by substituting carbon black with biochar
期刊: Journal of Cleaner Production
作者: Yang Goh, Samantha Lauro, Steven T Barber, Scott A Williams, Thomas A Trabold
摘要: There is growing interest in making printing inks more sustainable, and lowering the overall carbon footprint of the printing industry. A recent surge of research activity has emerged to develop “green” inks with bio-based solvents and binders, but little attention has been given to replacing the pigments that give inks their distinctive color. In this study, flexographic inks were formulated by replacing carbon black with a more sustainable biochar pigment derived from recycled paper, and fast growth cycle wood pulp. Obtained from fossil fuel sources, carbon black imparts high quality black prints, but at a significant environmental cost. Biochar, derived from recycled and renewable resources, has the potential to replace carbon black in many applications. Canceled United States currency stock was pyrolyzed at 1600 °C to produce a black biochar. Eastern White Pine (Pinus strobus) was selected for comparison, and converted to biochar at 550 °C and 1600 °C. Each biochar was functionalized and formulated into a simple ink composition optimized for flexographic printing. Prints exhibiting reflective optical densities exceeding 1.0 with excellent tone reproduction were obtained. Comparable print quality was achieved on both coated and uncoated paper substrates. Although further work would be required to fully optimize a biochar ink to match current print industry standards, a viable pathway for sustainable black ink development with good black density derived from recycled resources has been demonstrated. Our results indicate that it is possible to replace fossil fuel-based carbon black with biomass derived biochar, potentially resulting in cleaner production of flexographic printing inks.
239. 题目: Production of biochar from lignocellulosic biomass with acidic deep eutectic solvent and its application as efficient adsorbent for Cr (VI)
期刊: Journal of Cleaner Production
作者: Yali Zhang, Yahui Meng, Li Ma, Hairui Ji, Xianqin Lu, Zhiqiang Pang, Cuihua Dong
摘要: Deep eutectic solvents (DES) as potential green solvents have gained tremendous attention in biorefinery. Herein, we presented a simple one-pot method for biochar production in acidic DES (p-Toluenesulfonic acid monohydrate-choline chloride) at lower temperature (140 °C) using lignocellulose as feedstock. The results showed that the residual solid biomass treated in acidic DES were featured as biochar with excellent properties. The biochar exhibited the high content of carbon, plentiful oxygen-containing functional groups and porous structure, which endowed biochar with a superior adsorption capability on Cr (VI) up to 270.3 mg/g at 30 °C. The pseudo-second order model and Langmuir model can be used to perfectly describe the adsorption process, and adsorption behavior was assigned to chemical adsorption. In addition, the prepared biochar could be readily recycled via alkali-treated desorption. This study offered an environmental-friendly and cost-effective method for lignocellulose-derived biochar production.
240. 题目: The effect of biochar on the water-soil environmental system in freezing-thawing farmland soil: The perspective of complexity
期刊: Science of The Total Environment
作者: Qinglin Li, Tianxiao Li, Dong Liu, Qiang Fu, Renjie Hou, Song Cui
摘要: The moisture content of farmland soils is closely related to the farmland soil environment. Although biochar has been widely studied for farmland soil amelioration in tropical and temperate farmland soils, its application in areas of seasonally frozen soil is rare. In this study, field experiments were conducted to explore the effect of biochar on soil temperature and soil liquid moisture content in seasonally frozen soils and its corresponding mechanism. Biochar was applied to the soil at different rates (3 kg·m-2, 6 kg·m-2, 9 kg·m-2, and 12 kg·m-2) in autumn and spring. Daily monitoring data from the 20 cm soil-layer recorded for one year from the biochar application date were analyzed. The approximate entropy was introduced to explore the complex changes in soil temperature and soil liquid moisture content under biochar application in seasonally frozen soils. According to the calculation of approximate entropy, the application of biochar increased the complexity for most treatments. In the case of ignoring the heterogeneity of snowfall and uneven land tillage to the soil, we infer that this change was caused by changes in properties of the biochar due to the freeze-thaw cycle. The treatment under mixed biochar application in spring and autumn of 9 kg·m-2 had the smallest change in water and heat complexity. And the approximate entropy of this treatment is the smallest. Moreover, in the freezing period, the soil liquid moisture content is positively correlated with the biochar amount applied and negatively correlated with the biochar and soil mixing time. In the melting period, the opposite correlations occur. The changes in soil moisture conditions caused by freezing and thawing restrict the affinity of biochar for water. Therefore, the effect of biochar addition on the soil liquid moisture content varies among different freezing and thawing periods.