17361. 题目: Dramatic enhancement effects of l-cysteine on the degradation of sulfadiazine in Fe3+/CaO2 system
期刊: Journal of Hazardous Materials
作者: Jian Lu, Tenghao Wang, Yi Zhou, Changzheng Cui, Zhimin Ao, Yanbo Zhou
摘要: Excessive sulfonamides accumulated in soil and groundwater seriously menace the ecological environment and human health. The performance of a Fenton-like system applying Fe3+ and calcium peroxide (CaO2) in the presence of l-cysteine(l-cys) for sulfadiazine (SDZ) degradation was investigated. Compared with other chelating agents such as citric acid, butyric acid and Ethylenediaminetetraacetic acid, l-cys could effectively promote the SDZ removal in Fe3+/CaO2 system. With the addition of 0.5 mM l-cys, the SDZ degradation increased from 2.14% to 66.53% in 60 min. High concentration of HCO3− inhibited the degradation of SDZ while slightly negative effects on SDZ degradation were observed in the presence of Cl− or humic acid (HA) in l-cys/Fe3+/CaO2 system. Electron paramagnetic resonance (EPR) analysis and radicals scavenge tests affirmed the generation of OH and O2- in l-cys/Fe3+/CaO2 system. Possible degradation pathway of SDZ was speculated and the toxicity of SDZ intermediates was further evaluated. l-cys could enhance the reduction of Fe3+ to Fe2+ and reduced the Fe3+ precipitation due to the l-cys could form stable complexes with Fe3+. l-cys/Fe3+/CaO2 system exhibited high mineralization ability. Overall, these results indicated that l-cys is a promising chelating agent for sulfadiazine wastewater treatment.
17362. 题目: Bacillus cereus s-EPS as a dual bio-functional corrosion and scale inhibitor in artificial seawater
期刊: Water Research
作者: Shunling Li, Qing Qu, Lei Li, Ke Xia, Yan Li, Tingting Zhu
摘要: In this study, soluble extracellular polymeric substances (s-EPS) secreted by Bacillus cereus (B. cereus) were studied as a novel, dual bio-functional corrosion and scale inhibiting material, in artificial seawater. Static tests showed that the scale inhibition efficiency (SI%) was close to 87.60% for CaCO3 at the concentration of 80 mg/L s-EPS. Electrochemical technique results showed that s-EPS inhibition efficiencies, in relation to 316L stainless steel (SS), and at the concentration of 40 mg/L, reached 91.05% at 10 d and 91.16% at 30 d, respectively. The high anti-scale and anti-corrosion performance of s-EPS was related to their chelating, adsorption, and biomineralization abilities. s-EPS integrated with metal ions on the SS surface, resulting in formation of a thin but dense biomineralized film, which exhibited lasting corrosion resistance. Meanwhile, s-EPS controlled the kinetic pathway of CaCO3 biomineralized nucleation and crystal growth, which inhibited CaCO3 crystal precipitation. This finding suggests that B. cereus s-EPS may offer a green, sustainable, and economic strategy for anti-corrosion and anti-scale application in industry.
17363. 题目: Hydrogeomorphic controls on soil carbon composition in two classes of subalpine wetlands
作者: Ellen E. Daugherty, Georgina A. McKee, Robert Bergstrom, Sarah Burton, Céline Pallud, Robert M. Hubbard, Eugene F. Kelly, Charles C. Rhoades, Thomas Borch
摘要: Wetlands play a vital role in terrestrial carbon (C) sequestration, but the sensitivity of their C stocks to disturbance remains uncertain, requiring enhanced understanding of the processes that govern C storage and removal. The unique conditions in wetlands from different hydrogeomorphic (HGM) classes likely regulate the cycling, storage and vulnerabilities of wetland soil C stocks. To determine how differences in hydrogeomorphic setting influence soil organic carbon (SOC) processing, we compared C content and composition between depressional and slope wetlands located in the Colorado Rocky Mountains. Isolated depressional wetlands were characterized by seasonally declining water tables, slow discharge, high clay content, and thick organic horizons. Slope wetlands received perennial groundwater inputs and had coarser soil textures and thinner organic horizons. Seasonal snowmelt inputs coupled with low hydrologic discharge and higher clay content in depressional wetlands were predicted to sustain anoxic conditions, leading to high SOC content and chemically reduced C compounds. Depressional wetland soils had higher SOC content at depth and higher porewater DOC concentrations compared to slope wetland soils. Solid-state 13C nuclear magnetic resonance spectroscopy demonstrated that aliphatic compounds were the dominant SOC component in depressional wetlands compared to aromatic C forms in the slope wetlands. The higher prevalence of aliphatic carbon in depressional wetland soils suggests that stored SOC is protected by anaerobic conditions to a greater extent than in the slope wetlands, and that this SOC may be more vulnerable to drying and oxic conditions associated with wetland drainage and climate change.
17364. 题目: Effect of soil pH and organic matter content on heavy metals availability in maize ( Zea mays L.) rhizospheric soil of non-ferrous metals smelting area
期刊: Environmental Monitoring and Assessment
作者: Shengnan Hou, Na Zheng, Lin Tang, Xiaofeng Ji, Yunyang Li
摘要: Maize plant tissues and rhizosphere soil were collected from an agricultural area around the Huludao Zinc Plant in Liaoning Province, China, to investigate the effects of soil pH and organic matter content on heavy metal concentration and accumulation in different types of maize tissues. The mean pH of the soil samples was 7.02 (range 5.74–7.86), and the mean organic matter content was 31.03 g kg−1 (range 18.80–52.20 g kg−1). The average Cu, Zn, Pb, and Cd contents in soil were 2.92, 6.72, 7.95, and 16.28 times greater than the corresponding background values, respectively. The geo-accumulation index indicated that the soils were uncontaminated to moderately contaminated by Cu, moderately to strongly contaminated by Pb and Zn, and strongly contaminated by Cd. The average available Cu, Pb, Zn, and Cd contents in the soil samples were 16.34, 6.997, 69.77, and 0.190 mg kg−1, respectively, while their bioavailability coefficients were 28.53%, 1.65%, 40.44%, and 10.83%, respectively. The respective mean Pb and Cd concentrations in grain samples were 0.341 and 0.342 mg kg−1, which exceeded the maximum concentrations permitted by the Chinese National Standard. Thus, the maize grain is not safe for consumption and poses potential risks to human health. With the exception of Cu, the combined effect of pH and organic matter content had a stronger influence on the availability of heavy metals in soil compared with either factor alone. Cd uptake in maize plant tissues was affected by the combination of soil pH, organic matter content, and bioavailable Cd content in soil; however, the combination of these three factors had only slight effects on Cu, Zn, and Pb absorption in maize tissues.
17365. 题目: Colloidal transport of carbon and metals by western Siberian rivers during different seasons across a permafrost gradient
期刊: Geochimica et Cosmochimica Acta
作者: Ivan V. Krickov, Oleg S. Pokrovsky, Rinat M. Manasypov, Artem G. Lim, Liudmila S. Shirokova, Jerome Viers
摘要: In contrast to fairly good knowledge of dissolved (< 0.45 µm) and particulate (> 0.45 µm) fluxes of carbon, nutrients and metals from the land to the ocean, colloidal (1 kDa - 0.45 µm) forms of solutes are rarely quantified. This is especially true for Siberian rivers draining into the Arctic Ocean: because of organic-rich soils, colloidal fractions of elements are high and may sizably impact coastal biological processes. However, the main environmental parameters such as seasons, river size, climate, permafrost distribution and landscape parameters of the watershed controlling colloidal distribution of organic carbon (OC) and metals remain totally unknown. Here we used on-site centrifugation combined with ultrafiltration via 3, 30 and 100 kDa pore size membranes and 1 kDa dialysis to characterize colloidal size fractionation of OC and metals in 32 western Siberian rivers, ranging in size from 10 to 150,000 km2 watershed area, across a climate and permafrost gradient (from absent to continuous permafrost). The dominant forms of OC and metals was low molecular weight LMW< 3 kDa fraction and medium molecular weight (MMW3kDa-30 kDa) colloids. The LMW< 3 kDa fraction of OC increased in the order spring < autumn < summer, following progressive replacement of allochthonous medium and high molecular weight colloids in spring by autochthonous LMW organic ligands in summer; the latter possibly occurred due to exometabolites of plankton and periphyton. The LMW OC fraction became low again in autumn, presumably due to appearance of allochthonous DOM washed out by autumn rains from peat soil at maximum thawing depth. The size of the watershed had subordinate influence on colloidal distribution compared to seasons. The effect of landscape parameters of the watershed on the colloidal status of solutes was subordinate to seasonal and permafrost-zone controls. Overall, the ongoing environmental changes in WSL will likely decrease the proportion of mineral (Fe, Al - bearing) colloids of C and trace metals exported by rivers to the Kara Sea. As a result, the flux of dissolved C, micro-nutrients and metal toxicants may become increasingly bioavailable to coastal aquatic biota.
17366. 题目: Short communication on “Differentiating with fluorescence spectroscopy the sources of dissolved organic matter in soils subjected to drying” [Zsolnay et al. Chemosphere 38, 45–50, 1999]
作者: Susanne Halbedel, Peter Herzsprung
摘要: This article is a short, but very important comment to the often used humification index (HIX), assumed to indicate the degree of biochemical degradation of dissolved organic matter in water samples. HIX is commonly calculated by dividing the fluorescence intensity detected at longer wave lengths by the intensity detected at shorter wavelengths.However, we found typos in the original article that affect the used equation directly and thus the results. We compared the different ways to calculate HIX and found a strong correlation between all results. Nevertheless, we recommend to use only equation 1, especially if data from different studies should be compared.
17367. 题目: Predicting the sorption of azithromycin and levofloxacin to sediments from mineral and organic components
期刊: Environmental Pollution
作者: Seiya Hanamoto, Fumiaki Ogawa
摘要: Despite the strong association of azithromycin (AZM), a macrolide antibiotic, and levofloxacin (LVF), a quinolone antibiotic, to sediment, sorption data are scarce. We conducted sorption experiments with eight river sediments, their major clay minerals (illite and chlorite), a highly negatively charged clay mineral (montmorillonite), and an organic-matter-rich soil (Andosol). The sorption of AZM and LVF to the sediments was influenced by the concentration and type of coexisting inorganic cations as much as by reported organic cations. In addition, their linear sorption coefficients (Kd) to sediments were correlated with cation exchange capacity (CEC) but not organic carbon content, so cation exchange is the dominant sorption mechanism. Multiple linear regression analysis showed improved prediction of sediment Kd from CEC contributed by minerals and organic matter for AZM, but not for LVF. Kcec (= Kd/CEC) values of AZM were 2–3 orders of magnitude higher on minerals than on Andosol, but those of LVF ranged within a factor of 4. Therefore, mineral and organic components need to be separated in estimating AZM sorption to sediments. Sediment Kd values of AZM and LVF were satisfactorily predicted by a cation-exchange-based model using individual Kcec values on illite, chlorite, and Andosol (mean absolute error of 0.57 and 0.22 log units, respectively). Kcec values on montmorillonite and chlorite ranged within a factor of about 3 from those of illite for both antibiotics, and Kcec differences by mineral type would generally be negligible in model estimation. Because AZM was sorbed mostly to minerals in sediments, the model and sorption data can be applicable to various soils or sediments. Overall, the trend of LVF sorption corresponds to reported sorption of other organic cations, whereas remarkably higher AZM Kcec to minerals than to Andosol is attributable to its large lactone ring, higher molecular weight, or two charged amines.
17368. 题目: Biofilm characteristics, microbial community structure and function of an up-flow anaerobic filter-biological aerated filter (UAF-BAF) driven by COD/N ratio
期刊: Science of The Total Environment
作者: Hexi Zhou, Guoren Xu
摘要: The biofilm characteristics, microbial community structure and function in a lab-scale up-flow anaerobic filter-biological aerated filter (UAF-BAF) driven by COD/N ratio were investigated. Results showed that the TN removal rate of system reduced from 68.7% to 50.6% with COD/N ratio ranging from 10 to 3. Biofilm characteristics analysis indicated that the biomass, biofilm thickness, polysaccharide and protein contents in extracellular polymeric substance and dehydrogenase activity from biofilm in the UAF-BAF declined with the decrease of COD/N ratio. The biofilm structure visualized by confocal laser scanning microscopy displayed that the total cells and EPS content decreased as the COD/N ratio downshifted. 16S rRNA sequencing illustrated that Zoogloea and Pleomorphomonas were the major contributors to TN removal in the UAF, with dramatically decreasing abundance. Functional prediction indicated that the genes involved in nitrogen metabolism and nitrate reductase (EC 18.104.22.168) also decreased, which was responsible for the decrease of TN removal. This study provided insights into understanding of the biofilm structure and underlying ecological function in the UAF-BAF, which would help to regulate wastewater biofilm and improve process performance.
17369. 题目: Spatiotemporal variations of spectral characteristics of dissolved organic matter in river flowing into a key drinking water source in China
期刊: Science of The Total Environment
作者: Huan Zhang, Kangping Cui, Zhi Guo, Xiaoyang Li, Juan Chen, Zhaoguo Qi, Siyuan Xu
摘要: The characteristics of dissolved organic matter (DOM) in inflowing river, flowing into drinking water, have profound influences on the quality and safety of water. Here, ultraviolet–visible (UV–vis) spectroscopy and three-dimensional fluorescence (EEM) spectroscopy were combined to investigate the spatiotemporal variations of DOM in Nanfei River flowing into Chaohu Lake in China. 24 water samples and 24 surface sediments samples (including dry-to-wet transition season and wet season in 2018) were collected from different types of outlets. Parallel factor analysis (PARAFAC) model and correlation analysis were conducted to identify the primary sources of DOM. Two humic-like components (C1 235–250 nm/385–430 nm and C3 255–270 nm/455–510 nm) and one tryptophan-like component (C2 270–290 nm/320–350 nm) were effectively identified by PARAFAC model. The results showed DOM concentration presented significant spatiotemporal variations. The concentration was much lower in water than in surface sediments in dry-to-wet transition season, but higher in the wet season. Fluorescence index (FI), biological index (BIX) and humification index (HIX) were used to judge characteristic of DOM origination. These indexes indicated that, DOM in Nanfei River had both the characteristics of humus and autogenous, but neogene autogenic feature was stronger, which was largely due to mixture of water, resuspension and desorption of DOM in sediments and photochemical degradation. In addition, the characteristic parameter of molecular mass of DOM (the values of M) had an obvious linear relationship with the fluorescence intensity ratio of fulvic acid-like to humic acid-like (C1/C3), indicating that macromolecular substances could be removed by adding or improving membrane treatment. These provided technical support for improving quality and comprehensive treatment of drinking water sources.
17370. 题目: Dissolved organic matter in the deep TALDICE ice core: A nano-UPLC-nano-ESI-HRMS method
期刊: Science of The Total Environment
作者: Roberta Zangrando, Veronica Zanella, Ornela Karroca, Elena Barbaro, Natalie M. Kehrwald, Dario Battistel, Elisa Morabito, Andrea Gambaro, Carlo Barbante
摘要: Trace organic compounds in deep ice cores supply important paleoclimatic information. Untargeted analyses of dissolved organic matter provide an overview of molecular species in ice samples; however, sample volumes usually required for these analyses are generally not available from deep ice cores. Here, we developed an analytical method using a nano-UPLC-nano-ESI-HRMS to detect major molecular species in ice cores. Samples (4 μL) from the TALos Dome Ice CorE (TALDICE), allowed investigating molecular species across a range of depths including during glacial and interglacial periods. We detected 317 chemical species that were tentatively assigned to fatty acids, hydroxy fatty acids and their degradation products (oxo-fatty acids and dicarboxylic acids), as well as oxidation byproducts of isoprene and monoterpenes. These compounds indicate that the main sources of the organic fraction are microbes as well as primary and secondary aerosols. Interglacial samples encompass a wide range of species including compounds from the oxidation of isoprene and monoterpenes as well as unsaturated fatty acids, while the glacial samples contained less diverse species. This difference may be due to decreased temperatures during the glacial period inhibiting terrestrial vegetation growth and increasing the sea ice extent, thereby weakening the emission sources.
17371. 题目: Influence of land use and rainfall on the optical properties of dissolved organic matter in a key drinking water reservoir in China
期刊: Science of The Total Environment
作者: Yu Shi, Liuqing Zhang, Yuanpeng Li, Lei Zhou, Yongqiang Zhou, Yunlin Zhang, Changchun Huang, Hengpeng Li, Guangwei Zhu
摘要: The concentration, source and composition of dissolved organic matter (DOM) in aquatic ecosystems are associated with land use and hydrological connectivity between terrestrial and aquatic systems. However, direct evidence of the effects of rainfall and land use on the variability of DOM in aquatic ecosystems is very limited. In this study, chromophoric DOM (CDOM) absorption and fluorescence spectroscopy were used to elucidate how rainfall and land use affect the variability of CDOM in the watershed of Lake Tianmu, a key drinking water reservoir in the Yangtze River Delta. The mean values of the fluorescence intensity (Fmax) of parallel factor analysis-derived humic-like components (C1, C3, C6) and tryptophan-like components C5 were higher in the southeastern inflowing river mouths than those downstream of the lake outlet regions. The upstream tributaries were mainly dominated by humic-like materials, while the lake was mainly dominated by protein-like materials. The Fmax values of four humic-like components and two tryptophan-like components all increased significantly as the %woodland decreased, but %anthropogenic land use (%cropland + %urban construction area) increased. The Fmax of the humic-like components at the inflowing tributaries and the lake increased with increasing rainfall during storm events, and the value was especially pronounced at the inflowing river mouths. We concluded that land use and hydrological conditions play an important role in influencing the CDOM source and optical composition, and these findings provide insights for the understanding of aquatic ecosystem metabolism and reservoir water quality management.
17372. 题目: Biochar-induced metal immobilization and soil biogeochemical process: An integrated mechanistic approach
期刊: Science of The Total Environment
作者: Ali El-Naggar, Mi-Hee Lee, Jin Hur, Young Han Lee, Avanthi Deshani Igalavithana, Sabry M. Shaheen, Changkook Ryu, Jörg Rinklebe, Daniel C.W. Tsang, Yong Sik Ok
摘要: The nature of biochar-derived dissolved organic matter (DOM) has a crucial role in the interactions between biochar and metal immobilization, carbon dynamics, and microbial communities in soil. This study utilized excitation–emission matrix coupled with parallel factor analysis (EEM-PARAFAC) modeling to provide mechanistic evidence of biochar-induced influences on main soil biogeochemical processes. Three biochars produced from rice straw, wood, and grass residues were added to sandy and sandy loam soils and incubated for 473 d. Microbial and terrestrial humic-like fluorescent components were identified in the soils after incubation. The sandy loam soil exhibited a higher DOM with microbial sources than did the sandy soil. All biochars reduced Pb bioavailability, whereas the rice straw biochar enhanced the As bioavailability in the sandy loam soil. The biochar-derived aliphatic-DOM positively correlated with As bioavailability (r = 0.82) in the sandy loam soil and enhanced the cumulative CO2-C (r = 0.59) in the sandy soil. The promoted cumulative CO2-C in the sandy soil with all biochars correlated with the enhanced microbial communities, in particular, gram-positive (r = 0.59) and gram-negative (r = 0.59) bacteria. Our results suggest that the integration of EEM-PARAFAC with spectroscopic indices could be useful for a comprehensive interpretation of the soil quality changes in response to the application of biochar.
17373. 题目: Spatio-temporal heterogeneity in extracellular enzyme activities tracks variation in saprotrophic fungal biomass in a temperate hardwood forest
期刊: Soil Biology and Biochemistry
作者: Meghan G. Midgley, Richard P. Phillips
摘要: Saprotrophic fungi are the dominant producers of organic matter-degrading extracellular enzymes in forest soils, but the extent to which they drive spatio-temporal variation in enzyme activities is unclear. We quantified the relationships between saprotrophic fungal biomass and enzyme activities in a mature temperate hardwood forest by placing soil-filled ingrowth bags inside trenches. Trenches were located in replicate stands (n = 7) dominated by either arbuscular mycorrhizal (AM)- or ectomycorrhizal (ECM)-associated tree species, which reflect differences in soil substrate quality and nutrient availability. Additionally, we assessed the extent to which the relationships between saprotrophic fungal biomass and enzyme activities varied across seasons and were altered by experimental nitrogen (N) addition. Overall, both fungal production and enzyme activities differed between mycorrhizal types and across seasons, but were unaffected by N addition. Additionally, enzyme activities exhibited strong, positive relationships with saprotrophic fungal biomass. However, the relative production of carbon (C)-degrading enzymes was greater in stands dominated by AM-associated trees in the late growing season, and the relative production of N-degrading enzymes was greater in the late growing season across both AM- and ECM-dominated forest stands. These patterns reflected tree- and season-driven changes in microbial C and N limitation. As such, while the common assumption that microbial biomass and enzyme activities are positively correlated is robust for saprotrophic fungi, enzyme produced per unit biomass may not be consistent among stands and across seasons.
17374. 题目: Post-treatment of paint industry effluents by filtration using Andropogon biochar (Andropogon gayanus Kunth cv. Planaltina)
期刊: Environmental Science and Pollution Research
作者: Argemiro L. Pedrosa, Marcelo M. Pedroza, Grasiele S. Cavallini
摘要: This study evaluates the filtration potential of the biomass obtained from Andropogon grass (Andropogon gayanus Kunth cv. Planaltina) that was converted to biochar by pyrolysis. The biochar is used in filtration systems for the post-treatment of paint industry effluents. The biomass is characterized by elemental analysis (CHSN-O), determination of specific compounds (cellulose/hemicellulose/lignin), FTIR, and SEM. The produced biochar is characterized by SEM, TGA, and surface area analysis. The efficiency of the filters is evaluated by the following parameters: color, turbidity, removal of total solids (suspended and sedimentable), chemical oxygen demand (COD), and metals (Al, Cu, Zn, Co, Cd, and Cr(VI)). Over 99% removal of aluminum, cadmium, and hexavalent chromium is achieved. Moreover, almost 100% of COD and solids are removed, whereas turbidity and color are reduced by over 90%.
17375. 题目: Gradients of labile carbon inputs into the soil surrounding wood ant nests in a temperate forest
期刊: Biology and Fertility of Soils
作者: Veronika Jílková, Kateřina Jandová, Anna Vacířová, Jaroslav Kukla
摘要: Wood ants are common in temperate forests, and while building their nests and foraging for food, they transfer large amounts of organic matter and nutrients. Here, we tested the hypothesis that wood ants generate natural gradients of labile carbon (C) inputs into the soil surrounding their nests. We selected five medium-sized wood ant (Formica aquilonia) nests in a coniferous temperate forest and established sampling points at distances of 4, 30 and 70 m from each nest. Throughfall (honeydew + aboveground vegetation leachates) and litterfall were collected regularly during a vegetative season and were analysed for labile organic C content. In addition, soil from the organic horizon (Oe + Oa), surface mineral horizon (A) and subsoil mineral horizon (B) was collected and analysed for organic matter and nutrient contents. The labile C input in throughfall increased with distance from the nest (it was 1.5-fold greater at 70 m than at 4 m). C input changed during the vegetative season and was highest in June. Litterfall was not affected by the distance from the nest. Organic matter and nutrient contents were unaffected by distance from the nest in surface soil horizons but were significantly higher near the nest (4 m) than 70 m from the nest in the subsoil mineral horizon, suggesting that surface soils are less affected by the labile C inputs than subsoils. Finally, we suggest that the gradients in labile C input surrounding wood ant nests can be used to study the effects of labile C input changes on soil properties.
17376. 题目: Coadsorption of Cu(II) and tylosin/sulfamethoxazole on biochar stabilized by nano-hydroxyapatite in aqueous environment
期刊: Chemical Engineering Journal
作者: Zhen Li, Miao Li, Zhaoyan Wang, Xiang Liu
摘要: Antibiotics and heavy metals are frequently detected simultaneously in water environment. In this study, a biochar stabilized by nano-hydroxyapatite (nHAP@biochar) was used for the coadsorption of tylosin (TYL)/sulfamethoxazole (SMX) and Cu(II) in aqueous environment, which was well suited for real water samples. The physicochemical properties of nHAP@biochar were characterised by SEM image, zeta potential, FTIR, BET analysis, XPS and XRD. The pseudo-second-order model was better fit for the sorption kinetics data. Background electrolytes, ionic strength, humic acid (HA) and addition sequences presented a significant effect on the adsorption of TYL/SMX and Cu(II) when with or without Cu(II). The adsorption of TYL and Cu(II) increased with the increasing of ionic strength and HA, and compared with TYL, the influence on SMX was not obvious. Adsorption results exhibited that TYL obviously enhanced the Cu(II) adsorption capability and Cu(II) obviously enhanced the SMX adsorption capability. According to the results of FTIR and XPS, H-bond may be one of the main interactions of TYL with nHAP@biochar adsorption and weak π-π interactions and H-bond were two of the main interaction of SMX. TYL/SMX-Cu complexes were formed. In the system, the complexes were more on the formation of nHAP@biochar-TYL-Cu and nHAP@biochar-Cu-SMX, rather than on nHAP@biochar-Cu-TYL and nHAP@biochar-SMX-Cu, respectively.
17377. 题目: Broadened operating pH range for adsorption/reduction of aqueous Cr(VI) using biochar from directly treated jute (Corchorus capsularis L.) fibers by H3PO4
期刊: Chemical Engineering Journal
作者: Mingxin Chen, Feifei He, Dongwen Hu, Chongzhuo Bao, Qiang Huang
摘要: Biochar has attracted much attention as a green cost-effective adsorbent for heavy metal removals. However, previous studies generally found that biochar was only effective in a narrow low pH range for Cr(VI) removal, and less attention was paid to biochar which can be effectively operated in a wider range of pH. This study showed that the jute fiber-based biochar pretreated H3PO4 can availably remove and reduce Cr(VI) to Cr(III) in wastewater over a broadened operating pH range of 1–6, in which the intrinsic pH of Cr(VI) solution was included. For this, XRD, Raman, SEM, elemental analysis and N2 adsorption- desorption techniques were utilized to characterize the structure and compositions of the biochars. FTIR, XPS, Boehm titration and zeta potential measurements were performed to determine the surface group and charge distributions. It was revealed that in comparison with the biochar activated by KOH, H3PO4-treated biochar offered sufficient acidic groups such as phosphonic acid and carboxyl on the surface, from which the supplied protons could maintain the pH within a stable range of 1.9–3.4. XPS analysis exhibited that the electron-rich C–O, P–O and C–P bonds acted electron donating moieties to reduce high potential Cr(VI). Cr(VI) uptake experiments showed that Freundlich multilayer chemisorption occurred on the heterogeneous surface. Langmuir-Hinshelwood kinetic model suggested the surface reaction was the rate-controlling step. The examination for simulated samples confirmed that the H3PO4-treated biochar could control Cr(VI) pollution at the inherent pH in the environment.
17378. 题目: A facile foaming-polymerization strategy to prepare 3D MnO2 modified biochar-based porous hydrogels for efficient removal of Cd(II) and Pb(II)
作者: Zhiying Wu, Xiaoxiao Chen, Baoling Yuan, Ming-Lai Fu
摘要: A novel three dimensional MnO2 modified biochar-based porous hydrogel (MBCG) was fabricated to overcome the low sorption capacity and difficulty in solid-liquid separation of biochar (BC) for Cd(II) and Pb(II) removal. BC was initially modified by a rapid redox reaction between KMnO4 and Mn(II) acetate, and then incorporated into a polyacrylamide gel network via a rapid and facile free-radical polymerization. A foaming method was deliberately introduced during the fabrication to establish interpenetrated porous structure inside the network. Various characterizations were employed to examine the morphology, porous structures, chemical compositions, and mechanical properties of the samples. Adsorption performance of MBCG on Cd(II) and Pb(II) (isotherms and kinetics) as well as its desorption and reusability were also investigated. The results indicated that MnO2 modified biochars (MBC) were successfully introduced and homogeneously distributed in the porous bulk hydrogel, endowing MBCG with more uniform pore structure, excellent thermostability, remarkable mechanic strength, and superior adsorption performance. The maximum Langmuir adsorption capacity on Cd(II) and Pb(II) is 84.76 and 70.90 mg g−1, respectively, which is comparable or even larger than that of MBC. More importantly, MBCG can be rapidly separated and easily regenerated with an excellent reusability, which could retain 92.1% and 80.5% of the initial adsorption capacities of Cd(II) and Pb(II) after five cycles. These new insights make MBCG an ideal candidate in practical applications in water treatment and soil remediation contaminated with various heavy metals.
17379. 题目: Tracking and analysis of DBP precursors’ properties by fluorescence spectrometry of dissolved organic matter
作者: Zihong Fan, Hailing Yang, Shuangfei Li, Xin Yu
摘要: Disinfection by-products (DBPs) play a significant role in human health. Identification of the precursor of DBPs, which constitutes dissolved organic matter (DOM), can help optimize the processes in a drinking water treatment plant (DWTP). This is very important for obtaining more safe water. In this context, a one-year study was performed in a DWTP. Fluorescence spectra of DOM were quantified for determining DOM composition and properties, and the corresponding DBPs formation was analyzed. Hydrophobic neutral and acidic compounds were found to be the two predominant substances forming DBPs, which also were dominant in the DOM. Coagulation and sedimentation were not effective in DOM elimination. Besides, sand filtration caused organic compounds to increase by 14.8% on average, especially 28.59% for aromatic protein II and 18.7% for soluble microbial product-like compounds, which was due to metabolism by microorganisms present in the filter. Carbonaceous DBPs were elevated from 34.8 μg/L in source water to 42.5 μg/L in effluent, along with organic compounds increasing in filtration, and nitrogenous DBPs were under detection in winter. All DBPs appeared at a high level in summer. Accordingly, enhanced coagulation process and measures that can avoid the release of organic compounds during filtration have been suggested. As the source water was rarely affected by human activities in the study area and owing to the wide use of traditional treatment process, the data of this research can be regarded as environmental background values and the results are considered as a significant reference.
17380. 题目: Characterization of fluorescent dissolved organic matters in metalworking fluid by fluorescence excitation-emission matrix and high-performance liquid chromatography
作者: Jian Shen, Bo Liu, Jing Wu, Yidi Chai, Cheng Cheng, Chuanyang Liu, Rui Yan, Muhammad Farooq Saleem Khan
摘要: In recent years, precise environment supervision has gradually become vital in water pollution control, which requires the clear identification of dissolved organic matters (DOM) in wastewater. Metalworking fluid (MWF) is a type of wastewater with high toxicity. Over ten million m3 of MWF is discharged per year. However, its DOM characteristics have not yet been systematically investigated. Therefore, in this study, the fluorescent DOM (FDOM) of MWF was firstly characterized by excitation-emission matrix-parallel factor analysis (EEM-PARAFAC) and high-performance liquid chromatography (HPLC). Three fluorescent components (C1-C3) of the MWF from three metalworking plants (BO, TH, and YD) were identified. The peaks measured for C1 and C3 were attributed to tryptophan-like (Peak T) and humic/fulvic acid-like (Peak A + C) peaks, respectively, and the peaks at C2 were identified as humic-like (Peak A + M) or tryptophan-like (Peak T) peaks. There were differences in the C2 and C3 components of MWF from the three metalworking plants. The FDOM of MWF from the three metalworking plants exhibited similar polarity, but different apparent molecular weight distributions. In addition, the highest intensities of the three fluorescent peaks were sensitive to variations in the pH, humic acid (HA) concentrations, and metal ion levels (Cu2+, Fe3+, and Ni2+). The findings of this study not only indicate the FDOM characteristics of MWF, but also provide a promising method and valuable guidance for the practical monitoring of MWF in natural water bodies.