161. 题目: High-efficiency removal capacities and quantitative adsorption mechanisms of Cd2+ by thermally modified biochars derived from different feedstocks
作者: Heng Wang, Fei Huang, Zi-Lin Zhao, Ren-Ren Wu, Wei-Xin Xu, Peng Wang, Rong-Bo Xiao
摘要: Adsorption characteristics of Cd2+ on the three biochars modified by pyrolysis and calcination were investigated that were derived from rice straw (TRSB), chicken manure (TCMB) and sewage sludge (TSSB). The pH effect, adsorption kinetics, isotherms and thermodynamics, and desorption were determined, and qualitative analysis of adsorption mechanisms was performed by SEM, XRD, FTIR and XPS. Maximum adsorption capacities reached 177.28, 96.03 and 74.04 mg/g for TCMB, TRSB and TSSB, respectively, which were higher than that of many previously reported biochars. Even after five adsorption-desorption cycles, TCMB showed the strongest reusability without losing significantly adsorption capacity. This suggested that thermally modified biochars, particularly TCMB, could be a preferred adsorbent for Cd2+. Relative distribution of adsorption mechanisms was examined by direct and indirect calculation, in which the precipitation and cation-exchange dominated the whole chemisorption process, jointly accounting for 84% (TRSB) to 95% (TCMB) of total adsorption. While the complexation was of minor importance in total adsorption accounting for 5%-16%. The relationship of each mechanism with the properties of biochar was also discussed. These provided new insights on the adsorption effectiveness and mechanisms for Cd2+ in the aqueous solution that was critical for evaluating the application of modified biochars.
162. 题目: A potential Mg-enriched biochar fertilizer: Excellent slow-release performance and release mechanism of nutrients
期刊: Science of The Total Environment
作者: Weichen Luo, Ling Qian, Weiwei Liu, Xin Zhang, Qi Wang, Haiyang Jiang, Beijiu Cheng, Huan Ma, Zhengyan Wu
摘要: A potential Mg-enriched biochar fertilizer (MBF) was successfully synthesized via pyrolysis of MgCl2-enriched corn straw and high-efficiency reclaiming of N- and P-containing nutrients from biogas effluent. Mathematical modeling and column leaching method demonstrated that the MBF exhibited excellent slow-release performances of total P and N with sustainable release rates. Leaching experiment indicated that the final accumulative release ratios of N and P from MBF were 7 times and 6 times lower than those of chemical fertilizer (CF), respectively. The mechanism study reveals that the P-release performance of MBF was not only controlled by the low solubility of Mg￼P precipitates formed on the biochar surface, but also enhanced by the ‘P-trap’ effect of MgO through re-precipitation process of PO43−. Meanwhile, the N-release behavior of MBF was dominated by the multi-effects of biochar carrier, including the confinement effect and electrostatic attraction for NH4+, as well as the hydrogen bonds and pore-filling effect for N-containing organic matter. In addition, MBF significantly promoted the corn growth and enhanced the nutrient uptake efficiency of corn. These results suggested that MBF may therefore have promising potential in sustainable agriculture application with multiple environmental benefits.
163. 题目: Impacts of biochar on anaerobic digestion of swine manure: methanogenesis and antibiotic resistance genes dissemination
期刊: Bioresource Technology
作者: Shuo Yang, Zhiqiang Chen, Qinxue Wen
摘要: This work aimed to study the effects of biochar on methanogenesis and antibiotic resistance genes (ARGs) fate during anaerobic digestion (AD) of swine manure (SM) was investigated. Under the optimal biochar dosage of 5–10%, methane yield was significantly improved by 25%, ascribing to the enhancement of direct interspecies electron transfer (DIET). Biochar addition alleviated the need of cytochrome-c as interspecies electron connection components and enriched the microbes involved in DIET. Defluviitoga, Thermovirga and Cloacibacillus were dominant with biochar addition and might participate in DIET together with Methanothrix. The abundance of parC, tetX, blaCTX-M, blaTEM, aac(6′)-Ib-cr, ermB and tetW were significantly reduced in biochar treatments and intI1 removal increased by 15% in B-5% than the control. Structural equation models demonstrated that intI1 (λ = 0.59, P < 0.001) had the most standardized direct effects on ARGs, while biochar indirectly affected ARGs by changing intI1 (λ = 0.41, P < 0.01) and microbial structure (λ = −0.24, P < 0.05).
164. 题目: Comparison of the NO heterogeneous reduction characteristics using biochars derived from three biomass with different lignin types
期刊: Journal of Environmental Chemical Engineering
作者: Qing-Chao Gong, Liu-Qing He, Li-Hui Zhang, Feng Duan
摘要: The properties of biochars derived from three biomass with different lignin types were analyzed by low-pressure nitrogen gas adsorption (LP-N 2GA), Fourier transform infrared spectroscopy (FTIR), and Raman spectroscopy. In this study, the heterogeneous reduction characteristics of NO by Chinese fir biochar (FB), elm biochar (EB) and bamboo biochar (BB) were compared. The reaction temperature increases from room temperature to 1073 K at a fixed heating rate of 10 K/min. Results show that the main stage of heterogeneous NO reduction with three kinds of biochars can be divided into two zones: dynamic control zone and diffusion control zone. The lignin composed of coniferyl alcohol and sinapyl alcohol derivative units will form more oxygen-containing functional groups and hydroxyl groups on EB and BB surfaces. Among the three biochars in the dynamic control zone, EB showed the highest NO reduction rate (2.69 ppm/K) and the strongest oxidation resistance. The lignin composed of a polymer with coniferyl alcohol as a basic unit form the well-developed pore characteristic of FB. The adsorption performance of FB is the best, which improves the reduction of NO in diffusion control zone.
165. 题目: Changes in soil organic carbon across an atmospheric CO2 gradient under natural and artificial vegetation of semi-arid lands
期刊: Environmental Earth Sciences
作者: Habib Yazdanshenas, Mahkame Sadat Gozidepor Tehrani, Milad Khorrami Ajirloo, Farajollah Tarnian
摘要: Soil organic carbon (SOC) was studied across a gradient of 400–550 ppm CO2 in calcareous contaminated semi-arid areas. An experiment was performed under natural and artificial vegetation cover of Atriplex canescens (Pursh) Nutt. SOC and vegetation cover were investigated every 2 years from 2012 to 2018. Findings disclosed that there was a polynomial relation between SOC and CO2 concentration. The SOC change rate had the highest positive relationship with CO2 concentration in the uppermost 20 cm of soil: R2 = 0.96 and 0.47 in plantation and control areas, respectively. Moreover, plant life forms had a significant effect on the SOC in CO2 contaminated areas (P < 0.01). The highest correlation (R2 = 0.93–0.99) was observed between SOC rate changes and perennial cover percentage at a depth of 0–20 and 20–40 cm, respectively, through the time.
166. 题目: Do moisture conservation practices influence stability of soil organic carbon and structure?
作者: Avijit Ghosh, Amit K. Singh, Sunil Kumar, Madhab C. Manna, Pramod Jha, Ranjan Bhattacharyya, Manjanagouda S. Sannagoudar, Ramesh Singh, Suresh K. Chaudhari, R.V. Kumar
摘要: As soil erosion is a major threat for global food security, soil and water conservation (SWC) structures are essential in degraded lands of the tropics facing water scarcity. However, some fundamental questions regarding the impact of SWC measures on soil aggregate stability, organic carbon (SOC) pools within bulk soils and aggregates, and biological activities remain unexplored. A 11-year study was conducted, involving a combination of tree (Emblica officinalis) + grass (Cenchrus ciliaris) + legume (Stylosanthes seabrana), comparing in-situ soil water storage measures, staggered contour trenches (SWC1), continuous contour trenches (SWC2), stone mulch (SWC3), and vegetative barriers (SWC4), to a control (SWC0). We calculated three novel indices: biological activity index (BAI), oxidative stability (OXS), and normalized soil stability index (NSSI). SWC1 and SWC2 reduced soil erosion by ~63% and 51% compared to SWC0. Labile C concentration improved by ~47, 31, and 15% for SWC1, SWC2, and SWC4 compared to SWC0. SWC1 and SWC2 had 50 and 33% greater recalcitrant C than SWC0, respectively, in the top layer. Considerably higher amount of aggregate associated C was observed with SWC1 and SWC2 than with SWC0. NSSI values of SWC1 and SWC2 were ~1.92- and 1.87-fold higher than that of SWC0 in the upper layer. BAI was improved by 1.34–2.65 times under SWC conditions compared to the control. For macroaggregates, OXS of C for SWC1 and SWC2 were ~12% higher than that for SWC0 at the surface. Overall, fruit and pasture yield under SWC1 were ~51 and 82% higher than SWC0, respectively. System water productivity was ~61% higher for SWC1 compared with SWC0. Therefore, staggered contour trenching or continuous contour trenching could be recommended for improving soil structural stability and SOC storage and for reducing soil erosion in degraded lands of semi-arid, dry, tropical regions.
167. 题目: Study on the complexation of heavy metals onto biogas slurry DOM using two-dimensional correlation spectroscopy combined with the log-transformed synchronous fluorescence spectroscopy
期刊: Environmental Science and Pollution Research
作者: Yuanyuan Tian, Yi Wu, Yuyao Peng, Xujing Guo, Yunzhen Li, Benlin Dai, Tao Huang
摘要: The fluorescent components of dissolved organic matter (DOM) in biogas slurry can react with heavy metals (HMs) and affect the migration, transformation, toxicity, and bioavailability of HMs in soil. Fluorescence quenching titration combined with two-dimensional correlation spectroscopy (2D-COS) can reveal the binding mechanism between HMs and different fluorescent components of biogas slurry DOM. The logarithmic-transformed (log-transformed) 2D-COS can be used to decrease the difference in the fluorescence intensity between low-intensity and high-intensity fluorophores that provides a better insight into the binding mechanism between biogas slurry DOM and HMs. Synchronous maps suggest that protein-like substances are more susceptive to the variation of the concentration of metal ions than fulvic-like substances. Asynchronous maps show that the preferential bonding of Cu(II) and Cr(III) to humic-like substances can be found in the biogas slurry DOM, as well as Fe(III) and Pb(II) to protein-like materials. DOM-Cu(II) may lead to an increasing risk of the migration of Cu(II) from soil to water environment due to the low log K values in the range from 2.93 to 3.46. Protein-like substances can also increase the environmental risk of HMs when these low-stable complexes occur migration and transformation. The potential environmental risk of protein-like with HMs follows the order: Pb(II) > Cu(II) > Cr(III). Here we demonstrate that the log-transformed 2D-COS can also identify fluorescence components at longer wavelength with relatively low content and reveals their preferential binding sequence and the number of binding sites. The study on the complexation between biogas slurry DOM and HMs provides a scientific basis for the environmental chemical behavior of HMs after the application of biogas slurry in agricultural soils.
168. 题目: Ecotoxicological assessment of sewage sludge-derived biochars-amended soil
期刊: Environmental Pollution
作者: Beata Tomczyk, Anna Siatecka, Aleksandra Bogusz, Patryk Oleszczuk
摘要: The study aimed to evaluate the ecotoxicity of soil (S) amended with biochars (BCKN) produced by the thermal conversion of sewage sludge (SSL) at temperatures of 500 ºC, 600 ºC, or 700 ºC and SSL itself. The ecotoxicological tests were carried out on organisms representing various trophic levels (Lepidium sativum in plant, Folsomia candida in invertebrates, and Aliivibrio fischeri in bacteria). Moreover, the study evaluated the effects of three plants (Lolium perenne, Trifolium repens, and Arabidopsis thaliana) growing on BCKN700-amended soil on its ecotoxicological properties. The experiment was carried out for six months. In most tests, the conversion of sewage sludge into biochar caused a significant decrease in toxicity by adding it to the soil. The pyrolysis temperature directly determined this effect. The soil amended with the biochars produced at higher temperatures (600 ºC and 700 ºC) generally exhibited lower toxicity to the test organisms than the SSL. Because of aging, all the biochars lost their inhibition properties against the tested organisms in the solid-phase tests and had a stimulating influence on the reproductive ability of F. candida. With time, the fertilizing effect of the BCKN700 amended soil also increased. The aged biochars also did not have an inhibitory effect on A. fischeri luminescence in the leachate tests. The study has also demonstrated that the cultivation of an appropriate plant species may additionally reduce the toxicity of soil fertilized with biochar. The obtained results show that the conversion of sewage sludge to biochar carried out at an appropriate temperature can become a useful method in reducing the toxicity of the waste and while being safe for agricultural purposes.
169. 题目: Rapid formation of pyrogenic char (biochar) with high and low sorption capacity towards organic chemicals
期刊: Environmental Pollution
作者: Zaiming Chen, Jianfei Wang, Yuefeng Wang, Bing Li, Meizhen Wang
摘要: Pyrogenic char (biochar) with a high sorption capacity (B-HSC) can sequester hazardous chemicals (e.g., phenanthrene). However, when sorption inhibits chemical bioavailability (e.g., the herbicidal efficacy of diuron in soil), biochar with a low sorption capacity (B-LSC) is required to prevent sorption effects. The pyrolytic B-HSC generation has been reported, but information on B-LSC formation is scarce. How fast B-HSC and B-LSC could be generated is unknown until now. Here, biochars were rapidly prepared (the shortest heating time reached 5 min and the cooling time reached < 30 min) by a direct-pyrolysis method by directly exposing packaged rice straw and pine wood to 350 °C, 500 °C and 700 °C and out-of-furnace cooling at room temperature. The sorption of diuron, phenanthrene, and twelve other chemicals was investigated. B-HSCs were obtained within 30 min of rice straw pyrolysis, and the biochar Kd values quickly increased to 7-730-fold that of the raw biomass as −OH and C−O−C in (hemi)cellulose of rice straw rapidly degraded, increasing hydrophobic interactions between the char and chemicals (solubility ≤ 82.8 g/L). In contrast, B-LSCs were generated within 30 min of PW pyrolysis, and the Kd values of the biochars were 0.2-3.0-fold that of the raw biomass, as the surface area development and hydrophobicity-driven sorption were probably delayed by the late degradation of lignin aromatic C−O and phenolic −OH. Biochar amendment revealed an enhancement effect of B-HSC but not of B-LSC on soil sorption. The fast formation of B-LSC and B-HSC provides a guide to develop time- and cost-effective technique in pyrolytically producing weakly or strongly sorbing biochars for organic chemical management.
170. 题目: Magnetic CoFe2O4 nanocrystals derived from MIL-101 (Fe/Co) for peroxymonosulfate activation toward degradation of chloramphenicol
作者: Liu-Xi Yang, Jia-Cheng E. Yang, Ming-Lai Fu
摘要: In this study, porous magnetic CoFe2O4 nanocrystals (NCs) were successfully synthesized by using bimetal-organic framework (MOF) as a precursor, and used as catalysts to activate peroxymonosulfate (PMS) for the removal of chloramphenicol (CAP) in the solution. The structure and physicochemical properties of CoFe2O4 NCs were thoroughly examined by a series of characterization techniques. The results revealed as-synthesized CoFe2O4 had a nanorod-shaped structure with high specific surface area (83.00 m2·g−1) and pore volume (0.31 cm3·g−1). Furthermore, the degradation efficiency (100%) and the removal of total organic carbon (68.09%) were achieved after 120 min with 0.1 g/L CoFe2O4 NCs, 2 mM PMS and 10 mg/L CAP at pH of 8.20. In addition, effects of catalyst dosage, PMS dosage, initial pH values, CAP concentration and co-existing anions as well as natural organic matters in the solution on the degradation efficiencies were studied and all the removal can be well fitted with pseudo-first-order kinetic model (R2 > 0.96). Sulfate radicals (SO4•−) and hydroxyl radicals (HO•) were proved to be two main reactive species for CAP removal in CoFe2O4/PMS system based on quenching experiments. CAP was degraded by the main pathways of dichlorination, denitration, decarboxylation, hydroxylation, ring cleavage and chain cleavage on CoFe2O4/PMS system through high performance liquid chromatograph-mass spectrometry analysis. We believe that this study would be very meaningful to promote the applications of MOFs-derived catalysts on the SO4•− based advanced oxidation processes (SR-AOPs) for the environmental remediation.
171. 题目: Environmental factors-mediated behavior of microplastics and nanoplastics in water: A review
作者: Virender K. Sharma, Xingmao Ma, Binglin Guo, Kaiyi Zhang
摘要: The release of plastics in nature is an increasing global concern due to their degradation from macro-to microplastics (MPs) and even to nanoplastics (NPs), which are being recognized as a potential global threat to humans and environment. This paper summarizes the current knowledge on the effect of different environmental factors on the aggregation of MPs and NPs in aquatic environment. Stability (or extent of aggregation) of MPs and NPs vary with pH, ionic strength, ion type (monovalent, divalent, and trivalent), kind of minerals, and natural organic matter (NOM) of the aquatic environment. Electrostatic interactions between particles at different pH and ionic strength caused by salts of different valents govern the aggregation. In the presence of minerals (or inorganic colloids), net surface charge of mineral and surface potential of MPs and NPs (i.e., positive or negative surface functionality) play important roles in the heteroaggregation of MPs and NPs. In the presence of NOM, additional complex interactions including hydrophobic interactions and bridging are also involved in the aggregation of particles. Understanding the interactions of MPs and NPs of different surface charge with diverse environmental factors at a wide range of environmental conditions is pivotal to assess the mobility and the fate of plastic particles and their risk to human health and ecological systems.
172. 题目: Decadal nitrogen addition alters chemical composition of soil organic matter in a boreal forest
作者: Shun Hasegawa, John Marshall, Tobias Sparrman, Torgny Näsholm
摘要: Boreal forests store approximately 470 Pg of carbon (C) in the soil, and rates of soil C accumulation are significantly enhanced by long-term nitrogen (N) enrichment. Dissecting the compositional profile of soils could help better understand the potential mechanisms driving changes in C cycling under enriched N conditions. We examined the impacts of long-term N addition on the chemical composition of soil organic matter (SOM) in a mature boreal forest. Two large experimental plots (15 ha each) were established: a control and a fertilised plot. The latter received NH4NO3 fertilizer at an average rate of 75 kg N ha−1 year−1 for 12 years. While the centre of this plot received the prescribed amounts of fertilizer, the year-to-year variation in distribution of fertilizer around the designated edges of the plot created a gradient in N-loading. Along this gradient, a compositional shift in SOM in the organic horizon was assessed using two methods: pyrolysis-gas chromatography/mass spectrometry (GC/MS) and solid-state 13C nuclear magnetic resonance spectroscopy (13C NMR). Both of these methods revealed that the chemical composition of SOM changed with increasing N loading, with an increased fraction of lignin derivatives (i.e., aromatic, methoxy/N-alkyl C) relative to that of carbohydrate (i.e., O-alkyl C), accompanied by increased soil C mass (kg m−2) at the fertilised plot. Also, the relative abundance of N compounds in the pyrolysis products increased with the N loading, mainly due to increased methyl N-acetyl-α-D-glucosaminide in the F/H horizon, plausibly of microbial origin. Microbial N processing likely contributed to soil accumulation of fertilizer-derived N. Our results corroborate the hypothesis that addition of inorganic N suppresses enzymatic white-rot decomposition relative to non-enzymatic brown-rot oxidation. Taken together, our study suggests that N enrichment leads to a selective accumulation of lignin-derived compounds and points to a key role of such compounds for N-induced SOM accumulation.
173. 题目: Biochar engineering and ageing influence the spatiotemporal dynamics of soil pH in the charosphere
作者: Xuejiao Chen, Steven Lewis, Kate V. Heal, Qimei Lin, Saran P. Sohi
摘要: The charosphere, the interface microzone between biochar and soil, plays a vital role in biochemical processes following biochar application to soil. However, the development of the charosphere over time, and the pH dynamics within and around it, remain poorly understood as biochar ages. In this study, two kinds of biochars with distinct characteristics, a pristine biochar (BCSE) and a hydroxyapatite engineered biochar (BCHA), were subjected to artificial physicochemical ageing treatment. The localized impact of the fresh and aged biochars on soil pH were quantified, and spatiotemporal changes at the microscale visualized, using the planar optode technique. Association between the biochar characteristics and their charospheres was assessed using correlation and redundancy analyses to identify controls on charosphere properties. Significant localized effects on soil pH were induced by biochar application, with pH gradients around biochar particles forming gradually over 24 h. Fresh biochars generated charospheres with radii ranging from 1.13 mm to 1.63 mm. However, ageing treatment slightly narrowed the charosphere radius to 1.08–1.12 mm. The spatiotemporal variations of pH in the charosphere were closely related to biochar characteristics. Ageing treatment resulted in large increases in the oxygen (91%–349%) and available phosphorus (670%–1094%) contents of biochar, but decreases in ash content (42%–45%), as well as pH (26%–54%) and electrical conductivity (EC) (17%–64%) values. The pore structure of biochar was altered and minerals were lost during the ageing process, so that aged biochars had much smaller specific surface area compared to the fresh biochars. Correlation and redundancy analyses revealed that the biochar EC value was the main factor determining the charosphere radius and pH within it. This study is the first to visualize and compare the charosphere derived from different fresh and aged biochars at a high resolution. The results provide new insight into the pH dynamics of the charosphere and the availability of elements as biochar ages following application to soil, which are important for understanding nutrient availability to plants and mobility of soil contaminants.
174. 题目: Microbial necromass formation, enzyme activities and community structure in two alpine elevation gradients with different bedrock types
作者: Parag Bhople, Katharina Keiblinger, Ika Djukic, Dong Liu, Franz Zehetner, Sophie Zechmeister-Boltenstern, Rainer Georg Joergensen, Rajasekaran Murugan
摘要: Microbial necromass is an important part of soil organic carbon (SOC), but the changes in its contribution along elevational gradients and soil types are poorly understood. At two sites, the alkaline site Hochschwab and the acidic site Rauris, soil samples from three elevation levels and depths were analysed for amino sugars as microbial necromass indices, extracellular enzymes, and phospholipid fatty acids (PLFA) as microbial biomass indices. The three elevation levels at each site represented similar temperature and precipitation regimes. Microbial necromass contribution to SOC was lower (26%) at the alkaline site than at the acidic site (37%), indicating lower transformation of microbial biomass into stable SOC and support the increased accumulation of fungal necromass under N limitation at Hochschwab. Fungi generally dominate microbial necromass, with 88% at Hochschwab and 77% at Rauris. At the alkaline site Hochschwab, phenoloxidase, peroxidase and phosphatase enzymes activities were lower by 96%, 98% and 75%, respectively than at the acidic Rauris site, but not those of the hydrolytic enzymes β-glucosidase, exo-glucanase, exo-chitinase, and protease, indicating retarded decomposition of plant residues. Gram positive bacteria dominate bacterial biomass at both sites, with 70% at Hochschwab and 72% at Rauris. The higher fungal to bacterial PLFA ratio suggest increased contribution of fungi to total microbial PLFA at Hochschwab due to the better adaptability of fungi to the site-specific environmental conditions. Effects along alpine elevation gradients depend on vegetation induced changes in soil properties, which interact with bedrock properties.
175. 题目: Divergent effect of silicon on greenhouse gas production from reduced and oxidized peat organic matter
作者: Annkathrin Hömberg, Tanja Broder, Klaus-Holger Knorr, Jörg Schaller
摘要: Peatlands store about 30% of the global soil carbon (C) stock. The decomposition of peat C in these systems depends on environmental parameters – such as water table levels and corresponding availability of electron acceptors for microbial respiration. Due to the latter, potential peat decomposition depends also on whether the material is initially oxidized or reduced prior to decomposition experiments. Recent studies revealed the importance of silicon (Si) for peat decomposition. High amounts of biogenic Si were found in peatlands, in particular in minerotrophic fens, and the importance of Si for graminoids and decomposability of respective litter has been widely discussed. Furthermore, the availability of Si was reported to influence the binding of phosphorus (P) to iron (Fe) and thereby the conditions under which decomposition proceeds. Yet the influence of Si on greenhouse gas production in peat under different initial redox conditions is largely unknown. Therefore, we intended to test the effect of Si on greenhouse gas production under different initial electron acceptor availabilities for microbial respiration, such as the availability of ferric Fe. We conducted two incubation experiments with initially oxidized and reduced peat organic matter (OM). We hypothesized that Si can mobilize P from Fe minerals, which increases microbial activity, and leads to higher production rates of carbon dioxide (CO2) and methane (CH4). Using the two different materials, we studied how initial redox conditions would modify effects of Si. As the predominant form of Fe as either ferric Fe-(oxy)hydroxides or as ferrous Fe minerals (sulfides, carbonates) is important for interaction with Si, we further hypothesized that Si effects should be stronger in initially oxidized peat in presence of ferric Fe, compared to initially reduced peat with ferrous Fe only. For incubation experiments using formerly oxidized material the Si addition increased P concentrations in the pore water, and more CO2 was produced. The onset of methanogenesis was much stronger with than without addition of Si, indicating a more rapid depletion of electron acceptors by faster rates of respiration. We explain this by more P being available stimulating microbial activity, and also by a direct effect of Si on microbial activity and methanogenesis. The incubation of formerly reduced OM did not show any effects of Si on respiration processes, presumably due to the absence of ferric Fe phases. In conclusion, there was a clear difference in the effect of Si addition on decomposition of formerly oxidized compared to long term reduced OM, with only oxidized peat OM or peat with ferric Fe phases present showing clear Si effects. Consequently, redox conditions and availability of ferric Fe are a main control for Si effects on OM decomposition and nutrient availability. Little effects of Si can be expected under permanently reducing conditions and in absence of ferric Fe phases.
176. 题目: UF fouling behavior of allelopathy of extracellular organic matter produced by mixed algae co-cultures
期刊: Separation and Purification Technology
作者: Kuo Gao, Tian Li, Qingqing Zhao, Wan Liu, Junxia Liu, Yali Song, Huaqiang Chu, Bingzhi Dong
摘要: The extracellular organic matter (EOM) produced during algae bloom can cause serious ultrafiltration (UF) membrane fouling. Most previous relevant studies focused on the UF fouling caused by the EOM from mono-algae. In this study, the UF fouling behavior of EOMs from three typical algae species (Microcystis aeruginosa (MA), Chlorella (Chl) and Scenedesmus obliquus (SO)) of both mono-culture and their co-cultures were examined in a comprehensive manner through a lot of analyses including the redundancy analysis (RDA), PARAFAC, AFM measurement, etc. The results showed that the UF performance was significantly affected by the humic-like and tryptophan-like substances in the EOMs. While their content from co-cultures showed clear and separate promotion and inhibition characteristics against the mono-culture. Concurrently, the membrane filtration behavior exhibited that the normalized flux followed the sequence of MA + SO > Chl + SO > Chl > SO > MA > MA + Chl. The flux drop during EOMs filtration from Chl + SO was close to the mono-algae, while MA + Chl produced the most serious fouling and MA + SO the least. The combined mechanism (CM) model was adopted to evaluate the fouling mechanism of EOM from both mono-culture and co-cultures. The results indicated that intermediate blocking had a larger predominance over standard blocking on EOM fouling from mono-culture, while standard blocking played the predominant part on co-culture fouling. Finally, the membrane morphology detection indicated the EOM from MA + Chl formed a compact foulant layer on the membrane surface, which was due to the existence of more hydrophobic micro-molecules in the culture and resulted in the most significant flux drop.
177. 题目: Sorption of tetrabromobisphenol A onto microplastics: Behavior, mechanisms, and the effects of sorbent and environmental factors
期刊: Ecotoxicology and Environmental Safety
作者: Shengsheng Li, Ruixue Ma, Xiaohui Zhu, Chang Liu, Liangzhong Li, Ziling Yu, Xichao Chen, Zongrui Li, Yan Yang
摘要: Microplastics (MPs) and halogenated organic pollutants coexist in ambient water and MPs tend to sorb organic pollutants from surrounding environments. Herein, a study on the sorption behavior of tetrabromobisphenol-A (TBBPA) onto four different MPs, namely, polyethylene (PE), polypropylene (PP), polystyrene (PS), and polyvinyl chloride (PVC) was carried out. Effects of MPs properties and environmental factors, including the type, surface charge and pore volume as well as the ionic strength (Ca2+) and humic acid (HA) on the sorption of TBBPA were discussed. Results showed that the sorption of TBBPA onto the MPs could reached an equilibrium within 24 h, and the sorption capacities decreased in the following order —PVC (101.85 mg kg-1) >PS (78.95 mg kg-1) >PP (58.57 mg kg-1) >PE (49.43 mg kg-1). Adsorption kinetics data fitted by intraparticle diffusion model revealed both surface sorption and intraparticle diffusion contributed, in the interfacial diffusion stage approximately 11–29% of TBBPA slowly diffused onto the surface of the MPs, and finally, in the intraparticle diffusion stage. The increase of Ca2+ concentration could promote the sorption of TBBPA by PE, PP, and PS, but no significant alteration for PVC. For all the four MPs, HA was found to exert a negative effect on TBBPA sorption. The adsorption was mainly driven by hydrophobic partition and electrostatic interactions.
178. 题目: Colloidal Stability and Correlated Migration of Illite in the Aquatic Environment: The Roles of pH, Temperature, Multiple Cations and Humic Acid
期刊: Science of The Total Environment
作者: Xiaoyan Wei, Duoqiang Pan, Zhen Xu, Dongfan Xian, Xiaolong Li, Zhaoyi Tan, Chunli Liu, Wangsuo Wu
摘要: The mobility and environmental risk of colloids and associated pollutants are dependent on their dispersion stability under various conditions. In this work, the stability and correlated migration of illite colloids (IC) were systematically investigated over a wide range of aquatic chemistry conditions. The results showed that IC was aggregation favorable at low pH, low temperature and high ionic strength. The critical coagulation concentration (CCC) of IC increased exponentially with increasing values of r/Z3, following the Schulze-Hardy and Hofmeister series. Humic acid (HA) greatly mitigated colloid aggregation since the attachment of HA on IC surface increased the steric hindrance and electrostatic potential, and the enhancement of stability was linearly correlated with the HA concentration. The Derjaguin-Landau-Verwey-Overbeek (DLVO) model revealed that the interaction force deriving from van der Waals forces and electrostatic double-layer energy evolved as the aquatic chemistry varied, and the reduction in repulsion force between particles facilitated the colloid collision and then aggregation. The migration of IC in the porous sand column was highly correlated with the dispersion stability and filtration effect, the agglomerated colloids were redispersed and released when conditions favored dispersion. The illite colloids acted as efficient carriers for Eu(III) transport. These findings are essential for improving the understanding of the geological fate of environmental colloids and associated radionuclides.
179. 题目: Enhancing biochar sorption properties through self-templating strategy and ultrasonic fore-modified pre-treatment: characteristic, kinetic and mechanism studies
期刊: Science of The Total Environment
作者: Jingtao Hu, Xin Zhou, Yexin Shi, Xiaojing Wang, Huiqin Li
摘要: The traditional anaerobic sewage treatment facilities are unsuitable for the widely uncontrolled spread of antibiotic residues in hospital or on livestock farm, which have raised the risk levels of high concentrations of antibiotic residues leakages and seriously threatened the aquatic ecology safeties. Thus, to develop an effective adsorbent with safe, low cost, and high firmly adsorptive capacity are imminent required. In this investigated, a self-templating hydrothermal alkali fore-modified & ultrasonic treatment was developed to achieve the highly adsorptive capacity and low desorption rate of biochar. As expected, the prepared biochar adsorbents present plenty of surface functional groups and micro pores. The BET value is raised up 1452 cm2·g-1 for biochar treated by the associated alkali fore-modified and ultrasonic treatment (UFB), whereas it is only 415.8 cm2·g-1 for the biochar treated by traditional carbonization (AC) and 1205 cm2·g-1 for the biochar by further hydrothermal alkali fore-modification (FB). Congruously, UFB exhibits the removal abilities of 397.70 mg·g-1 of levofloxacin (LEV) and 320.99 mg·g-1 of chlorotetracycline (CTC), 3.5~6.3 times absorbability towards familiar antibiotics than traditional biochar. Moreover, the corresponding the lowest desorption of 1.30 mg·g-1 (LEV) and 0.43 mg·g-1 (CTC) mg·g-1 by UFB have been confirmed. Meanwhile, Furthermore, both the adsorption and desorption mechanisms have been addressed by kinetic studies, pore width distributions, XPS and FTIR surveys. It is proposed the fore-modified treatment is more helpful for carbon functionalization while the ultrasonic treatment dedicates to the largely microporous structures. Consequently, the adsorption’s capacity and stability of UFB adsorbents is large promoted due to its more micro- and meso-porous structure through a jointly hydrothermal alkali fore-modified and ultrasonic treatment. The present investigation will provide a novel alternative preparation strategy of the highly efficient adsorbent for emergency medical wastewater treatment.
180. 题目: Bioprospecting of exopolysaccharide from marine Sphingobium yanoikuyae BBL01: production, characterization, and metal chelation activity
期刊: Bioresource Technology
作者: Shashi Kant Bhatia, Ranjit Gurav, Yong-Keun Choi, Tae-Rim Choi, Hyun-joong Kim, Hun-Suk Song, Sun Mi Lee, Sol Lee Park, Hye Soo Lee, Yun-Gon Kim, Jungoh Ahn, Yung-Hun Yang
摘要: In the present study, an exopolysaccharide (EPS)-producing bacterial strain was isolated from the Eastern Sea (Sokcho Beach) of South Korea and identified as Sphingobium yanoikuyae BBL01 Media optimization was performed using response surface design, and a yield of 2.63±0.02 g/L EPS was achieved. Purified EPS produced using lactose as the main carbon source was analyzed by GC-MS and found to be composed of α-D-xylopyranose (28.6±2.0%), β-D-glucopyranose (21.0±1.6%), α-D-mannopyranose (18.5±1.2%), β-D-mannopyranose (13.1±1.4%), β-D-xylopyranose (10.2±2.1%), α-D-talopyranose (5.9±1.1%), and β-D-galacturonic acid (2.43±0.8%). Interestingly, different carbon sources (glucose, galactose, glycerol, lactose, sucrose, and xylose) showed no effect on EPS monomer composition, with a slight change in the mass percentage of various monosaccharides. Purified EPS was stable up to 233 °C, indicating its possible suitability as a thickening and gelling agent for food-related applications. EPS also showed considerable emulsifying, flocculating, free-radical scavenging, and metal-complexion activity, suggesting various biotechnological applications.