论文检索

总访问量：2724234次

总访客量：122731人

所有论文

22781. 题目: Biochar-based engineered composites for sorptive decontamination of water: A review
文章编号: N19050113
期刊: Chemical Engineering Journal
作者: K.S.D. Premarathna, Anushka Upamali Rajapaksha, Binoy Sarkar, Eilhann E. Kwon, Amit Bhatnagar, Yong Sik Ok, Meththika Vithanage
更新时间: 2019-05-01
摘要: Biochar (BC) exhibits a great potential as an adsorbent in decontamination of water. To improve the adsorption capabilities and impart the particular functionalities of BC, various methods (chemical modification, physical modification, impregnation with different materials, and magnetic modification) have been developed. As compared to surface modifications, BC-based composites provide various technical and environmental benefits because they require fewer chemicals, lesser energy, and confer enhanced contaminant removal capacity. Therefore, this review focuses on BC composites prepared by the combination of BC with different additives including metals, metal oxides, clay minerals, and carbonaceous materials, which greatly alter the physicochemical properties of BC and broaden its adsorption potential for a wide range of aquatic contaminants. Techniques for the preparation of BC composites, their adsorption potentials for a variety of inorganic and organic environmental contaminants, factors affecting BC properties and the adsorption process, and the mechanisms involved in adsorption are also discussed. Modification typically alters the surface properties and functionalities of BC composites including surface area, pore volume, pore size, surface charge, and surface functional groups. Hence, modification enhances the adsorption capacity of BC for most organic and inorganic compounds and ions. Nevertheless, some modifications negatively affect the adsorption of certain contaminants because of various factors including obstruction of pores due to over coating and development of same charge as contaminant on the surface of BC. However, the use of BC composites in environmental remediation is still in its infancy, and further research and development is needed to reach scalability and commercialization of the new technology.
图文摘要:

22782. 题目: Effects of KMnO₄/NaHSO₃ pre-oxidation on the formation potential of disinfection by-products during subsequent chlorination
文章编号: N19050112
期刊: Chemical Engineering Journal
作者: Yating Zhu, Xin Yang, Junlian Qiao, Xin Zhang, Xiaohong Guan
更新时间: 2019-05-01
摘要: Bisulfite-activated permanganate oxidation (PM/BS) technology is an emerging oxidation process that can rapidly oxidize organic contaminants and degrade some permanganate-resistant organic contaminants. For the first time, the influences of PM/BS technology as a pre-oxidation process on the formation potentials of disinfection by-products (DBPFPs) during chlorination of humic acid (HA) solution and three natural water samples were investigated. The results revealed that PM/BS pre-oxidation only slightly affected the DBPFPs of HA in the absence of Br^- although it changed the structure of HA according to the fluorescence characterization result. With the presence of Br^-, PM/BS pre-oxidation enhanced the generation of trihalomethanes but inhibited that of nitrogenous DBPs (N-DBPs) during chlorination of HA. The toxic risk analysis showed that the toxicity of the generated DBPs from chlorinating HA solution without Br^- only changed slightly after PM/BS pre-oxidation but it was decreased by 14% in the presence of 150 μg/L Br^- due to PM/BS pre-oxidation. This should be associated with the inhibiting effect of PM/BS pre-oxidation on the generation of N-DBPs and several haloacetic acids in the presence of Br^-. Because of the complex matrix of natural water samples, PM/BS pre-oxidation had minor influence on the amount and the potential toxicity of DBPs generated during chlorination. The above results suggested that PM/BS technology could be an alternative of the drinking water pretreatment.
图文摘要:

22783. 题目: Investigating the use of microdialysis and SEC-UV-ICP-MS to assess iodine interactions in soil solution
文章编号: N19050111
期刊: Chemosphere
作者: O.S. Humphrey, S.D. Young, E.H. Bailey, N.M.J. Crout, E.L. Ander, E.M. Hamilton, M.J. Watts
更新时间: 2019-05-01
摘要: Element cycling in the terrestrial environment is heavily reliant upon processes that occur in soil solution. Here we present the first application of microdialysis to sample iodine from soil solution. In comparison to conventional soil solution extraction methods such as Rhizon™ samplers, centrifugation, and high-pressure squeezing, microdialysis can passively sample dissolved compounds from soil solution without altering the in-situ speciation of trace elements at realistic soil moisture conditions. In order to assess the suitability of microdialysis for sampling iodine, the permeability factors and effect of perfusion flowrate on I⁻ and IO₃⁻ recovery was examined in stirred solutions. Furthermore, microdialysis was used to sample native soluble iodine at a range of water contents and iodine-enriched soils to investigate iodine soil dynamics. Total iodine concentrations were measured using ICP-MS. Inorganic species and the molecular weight distribution of organically bound iodine were determined by anion exchange and size exclusion chromatography (SEC) coupled to an ICP-MS, respectively. The most effective recovery rates in stirred solution were observed with the slowest perfusion flowrate yielding 66.2 ± 7.1 and 70.5 ± 7.1% for I⁻ and IO₃⁻, respectively. Microdialysis was proven to be capable of sampling dissolved iodine from the soil solution, which accounted for <2.5% of the total soil iodine and speciation followed the sequence: organic-I > I⁻ > IO₃⁻. The use of SEC coupled to (i) UV and (ii) ICP-MS analysis provided detail regarding the molecular weight distribution of dissolved org-I compounds. Dissolved org-I was detected with approximate molecular weights between 0.1 and 4.5 kDa. The results in this study show that microdialysis is a suitable technique for sampling dissolved iodine species from soils maintained at realistic moisture contents. In addition, inorganic iodine added to soils was predominately bound with relatively low molecular weight (<4.5 kDa) soluble organic matter.

22784. 题目: Effect of sodium concentration on mobilization and fate of trace metals in standard OECD soil
文章编号: N19050110
期刊: Environmental Pollution
作者: Ludovico Pontoni, Marco Race, Eric D. van Hullebusch, Massimiliano Fabbricino, Giovanni Esposito, Francesco Pirozzi
更新时间: 2019-05-01
摘要: The effect of different Na concentrations on the fate of trace metals (Cd, Cu, Ni, Zn) in standard OECD soil was evaluated by performing soil leaching column experiments. Five Na concentrations added in synthetic irrigation water (0, 1, 5, 10, 50 mM) were studied in order to evaluate the fate of the metals contained in both the irrigation water leachate and the soil layer. In all experiments, metals mostly accumulated on the top soil layer (0–0.5 cm), at variable concentrations according to the Na content in the artificial irrigation water. Nevertheless, concentration peaks of metal contamination occurred at different sampling time in the soil leachates depending on the metal and on influent water sodicity. Peaks of metals in the leachate appeared simultaneously with the release of organic matter and/or release of Al, suggesting significant involvement of colloids in metals transport. Sodium concentration (10–50 mM) was demonstrated to highly reduce colloidal mobilization leading to the accumulation of more than 95% of the influent metal in the top soil layer. Conversely, low Na concentrations (1–5 mM) favored colloidal transport leading to the recovery of metals in the soil leachates.
图文摘要:

22785. 题目: Brown Carbon in the continental outflow to the North Indian Ocean
文章编号: N19050109
期刊: Environmental Science: Processes Impacts
作者: Srinivas Bikkina, Manmohan Sarin
更新时间: 2019-05-01
摘要: In this manuscript, we synthesize the size-distribution and optical properties of the atmospheric water-soluble fraction of light-absorbing organic carbon (aka Brown Carbon: BrC) in the continental outflow from the Indo-Gangetic Plain (IGP) in S. Asia to the N. Indian Ocean. A comparison of the mass absorption coefficient of water-soluble BrC (babs-BrC-365nm) in PM2.5 with that in PM10 sampled over the Bay of Bengal reveals the dominance of BrC in fine mode. Furthermore, the babs-BrC-365nm shows significant linear relationship with mass concentrations of airborne particulate matter, water-soluble organic carbon (WSOC) and non-sea-salt-K+ in the continental outflow from IGP. This observation emphasizes the ubiquitous nature and significant contribution of water-soluble BrC from biomass burning emissions (BBEs). A comparison of absorption properties from this study with the global datasets, it is discernible that BBEs dominate BrC absorption. Furthermore, the imaginary refractive index of water-soluble BrC (kWSBrC-365nm) in marine aerosols sampled over N. Indian Ocean during November is significantly higher than during December-January months. Thus, significant temporal variability is associated with crop-residue burning emissions in the IGP on the composition of BrC over N. Indian Ocean. Our estimates show that the babs-WSBrC-365nm and kWSBrC-365nm from post-harvest crop-residue burning emissions in the IGP are much higher than the BBEs from the SE-United States and Amazonian forest fires. Another major finding of this study is the lack of significant relationship between kWSBrC-365nm and the mass ratio of elemental carbon (EC) to particulate organic matter (OM), as previously suggested by chamber experiments to model varying BrC absorption properties in ambient aerosols. Therefore, considerable spatio-temporal variability prevails among emission sources (wood burning vs. crop-residue burning), which needs to be considered while assessing the regional radiative forcing of BrC relative to major absorbing elemental carbon (EC).

22786. 题目: Importance of nutrient availability for soluble microbial products formation during a famine period of activated sludge: Evidence from multiple analyses
文章编号: N19050108
期刊: Journal of Environmental Sciences
作者: Tahir Maqbool, Jinwoo Cho, Jin Hur
更新时间: 2019-05-01
摘要: Much remains unknown about compositional variations in soluble microbial products (SMP) with the shift of the substrate condition from a feast to a famine phase in biological treatment systems. This study demonstrated that the formation of SMP could be suppressed by up to 75% during the famine phase with the addition of essential nutrients. In contrast, presence of electron acceptor did not play any significant role during the stress condition, showing the similar amounts of SMP (r = 0.98, p < 0.05) formation between the bioreactors supplied with air and N₂. The SMP formed in the famine phase was more bio-refractory in the famine versus the feast phase with a linear correlation shown between the production and their aromatic structures in the composition (R² > 0.95). The fluorescence excitation–emission matrix coupled with parallel factor analysis (EEM-PARAFAC) revealed the presence of four different fluorescent components, including two protein-like (C1 and C4), fulvic-like (C2), and humic-like (C3) components, in the SMP and bEPS formed at different conditions. Both C1 and C4 showed increasing trends (R² > 0.95) with the length of starvation in the bioreactors without essential nutrients. Nutrient availability was found to be a key factor to quench the production of large-sized biopolymers. This study provides a wealth of information on operation conditions of activated sludge treatment systems to minimize large sized SMP molecules (particularly proteins), which typically exert many environmental concerns to effluent organic matter quality.

22787. 题目: Occurrence of aliphatic biopolymer in chlorophyceae algae and cyanobacteria-rich phytoplanktons
文章编号: N19050107
期刊: Organic Geochemistry
作者: Dainan Zhang, Yu Yang, Jianfang Hu, Yong Ran, Jingdong Mao
更新时间: 2019-05-01
摘要: Two cultured chlorophyceae algae and two cyanobacteria-rich phytoplanktons were separated into five fractions, and characterized by ¹³C cross polarization/total sideband suppression (CP/TOSS) nuclear magnetic resonance (NMR), X-ray photoelectron spectroscopy (XPS), and Rock-Eval and closed pyrolysis analyses. The structures of the acid nonhydrolyzable organic matter (NHOM) fractions were similar to those of poly(methylene)-rich aliphatic algaenan. We found that the cyanobacteria-rich phytoplanktons contained aliphatic nonhydrolyzable biopolymers. The NMR and Rock-Eval analyses showed that the isolated NHOM exhibited high oil-prone potentials. Pyrolysis analysis of the field-collected NHOM from Liuhuahu Park in Guangzhou (GP_NHOM) indicated that it exhibited high oil-prone potentials and comprised a long, saturated and unbranched hydrocarbon chain (up to C₃₃) structural unit. The maximum oil and gaseous hydrocarbon generation potentials reached 55.9% and 7.2%, respectively, and were very close to those derived from ¹³C CP/TOSS NMR, suggesting that ¹³C NMR is an effective approach to evaluate the oil and gas production potentials. This investigation is critical to the understanding of kerogen formation mechanism through selective preservation and the generation mechanism of biocrude oil.

22788. 题目: Expression of the nirS, hzsA, and hdh genes and antibiotic resistance genes in response to recovery of anammox process inhibited by oxytetracycline
文章编号: N19050106
期刊: Science of The Total Environment
作者: Qian-Qian Zhang, Yi-Heng Zhao, Cheng-Jie Wang, Yu-Hui Bai, Dan Wu, Jing Wu, Guang-Ming Tian, Man-Ling Shi, Qaisar Mahmood, Ren-Cun Jin
更新时间: 2019-05-01
摘要: The inhibitory effects of oxytetracycline (OTC) on the anaerobic ammonium oxidation (anammox) performance were relieved by employing bio-augmentation (BA) tactics. However, the recovery mechanism was vague. The response of specific anammox activity (SAA), heme c, functional genes, extracellular polymeric substance (EPS) and antibiotics resistance genes (ARGs) to OTC inhibition and BA aid were traced in the present study. The results indicated that response of SAA, heme c content and functional genes, such as nirS, hzsA and hdh to OTC inhibition were not synchronous. The presence of the tetC, tetG, tetX, and intI1 genes enhanced the resistance of anammox sludge to OTC, thus accelerating the performance recovery when aided by BA. A significant correlation existed between number of anammox 16S rRNA gene copies and protein level in the soluble microbial products (SMP), between tetG gene relative abundance and polysaccharose in SMP and between tetG gene relative abundance and protein in bound EPS (EPSs). In nutshell, the current findings provide the first description of a recovery mechanism regarding OTC-inhibited anammox performance aided by BA based on functional genes and highlights the contribution of ARGs and the self-resistance ability of EPS.
图文摘要:

22789. 题目: Geochemical discrimination of bulk organic matter in surface sediments of the Cross River estuary system and adjacent shelf, South East Nigeria (West Africa)
文章编号: N19050105
期刊: Science of The Total Environment
作者: Solomon Felix Dan, Su-Mei Liu, Bin Yang, Enobong Charles Udoh, Unyime Umoh, Ita Ewa-Oboho
更新时间: 2019-05-01
摘要: Knowledge of the sources, distribution and fate of organic matter (OM) in estuarine and adjacent shelf sediments are important to the understanding of global biogeochemical cycles. Bulk organic carbon (C-org), total nitrogen (TN), biogenic silica (BSi), stable carbon (δ¹³C-org) and nitrogen (δ¹⁵N) isotopes, and sediment grain sizes were measured to study the spatial distributions and sources of sediment OM in the Cross River Estuary system (CRES), a tropical estuary system and adjacent shelf. Surface sediments in the CRES were predominantly composed of clayey silt and sandy silt, while the adjacent shelf sediments were mainly silty sand. The range for the studied parameters was −28.79‰ to −22.20‰ for δ¹³C-org, −1.32‰–6.31‰ for δ¹⁵N, 6.7–29.2 for C-org/N ratios, 0.08%–0.33% for TN, 0.24‰–0.74‰ for BSi, and 0.47%–5.28% for C-org, and their spatial distributions showed a general decreasing trend in both terrestrial and estuarine OM from the riverine regions to the adjacent shelf. Based on the three end-member mixing model using δ¹³C and δ¹⁵N isotopic values, ~58.01 ± 15.32% of sediment OM was found to be derived from terrestrial sources dominated by C₃ vascular plants, while ~26.34 ± 9.71% was attributed to estuarine sources dominated by aquatic macrophytes, and ~15.65 ± 12.37% from marine plankton. Other sources of OM identified included soils underlain C₃ vascular plants and agricultural farms enriched with N, sewage, and petroleum hydrocarbons. The relationship between C-org vs. BSi, and the atomic BSi/Corg ratio suggested that diatoms also play an important role in OM sequestration in surface sediment of the CRES and adjacent shelf. The correlations of δ¹³C-org and δ¹⁵N vs. C-org/N resulted in scatter plots, indicating that the distribution of OM in the CRES may have been influenced by post depositional processes, fixed inorganic N adsorbed on fine-grained sediments, microbial degradation, and sediment grain size.
图文摘要:

22790. 题目: Enhancement of anaerobic digestion effluent treatment by microalgae immobilization: Characterized by fluorescence excitation-emission matrix coupled with parallel factor analysis in the photobioreactor
文章编号: N19050104
期刊: Science of The Total Environment
作者: Weijia Gong, Binghan Xie, Shihai Deng, Yuhui Fan, Xiaobin Tang, Heng Liang
更新时间: 2019-05-01
摘要: The bacterial-microalgal consortium has been investigated to anaerobic digestion effluent (ADE) treatment in the photobioreactor (PBR). However, the high concentrations of nutrients reduced the ADE treatment efficiency and the transformation of organic pollutants in PBR was still unclear. In this study, two-sequencing batch PBRs were operated with suspended Microcystis aeruginosa (M. aeruginosa, SMA) and immobilized M. aeruginosa (IMA) to compare the ADE treatment performance. Fluorescence excitation-emission matrix coupled with parallel factor analysis (EEM-PARAFAC) was conducted to identify organics degradations. The results showed that the proportion of living M. aeruginosa cell (86.4%) in PBR (IMA) was highly significant (p < 0.05) higher than that in PBR (SMA) (75.2%). This indicated immobilized microalgae beads enhanced the resistance to the high concentration of nutrients in PBR (IMA). EEM-PARAFAC analysis displayed the biodegradation order in the bacterial-microalgal consortium system was humic-like substances > tyrosine-like substances > tryptophan-like substances. The removals of humic-like matters (94.05 ± 0.92%) and tyrosine-like matters (91.13 ± 2.49%) in PBR (IMA) were significantly (p < 0.01) higher than those in PBR (SMA). Notably, the average removals of nutrients in PBR (IMA) were significantly (p < 0.05) higher than those in PBR (SMA). This result verified that microalgae immobilization benefitted nutrients removals with 93.05 ± 1.45% of NH₄⁺-N and complete PO₄³⁻-P removal in PBR (IMA). Moreover, the enrichment of functional genera Flavobacterium and Opitutus contributed to decreasing the organics loadings and strengthening the ADE treatment performance. Therefore, this study verified microalgae immobilization enhanced the actual ADE treatment. Additionally, fluorescent organic pollutants degradations were further evaluated by EEM-PARAFAC analysis in the bacterial-microalgal consortium.
图文摘要:

22791. 题目: Effects of brownification and warming on algal blooms, metabolism and higher trophic levels in productive shallow lake mesocosms
文章编号: N19050103
期刊: Science of The Total Environment
作者: Heidrun Feuchtmayr, Thomas G. Pottinger, Alanna Moore, Mitzi M. De Ville, Laurie Caillouet, Heather T. Carter, M. Gloria Pereira, Stephen C. Maberly
更新时间: 2019-05-01
摘要: An increase of dissolved organic carbon (DOC) in inland waters has been reported across the northern temperate region but the effects of this on whole lake ecosystems, often combined with other anthropogenic stressors like nutrient inputs and warming, are poorly known. The effects of these changes on different component of the ecosystem were assessed in an experiment using twenty-four large (3000L) outdoor mesocosms simulating shallow lakes. Two different temperature regimes (ambient and ambient +4 °C) combined with three levels of organic matter (OM, added as filtered peaty water), simulating the DOC increase that is predicted to take place over the next 4 to 21 years were used. Neither temperature nor OM had significant effects on net ecosystem production, respiration or gross primary production. Phytoplankton chlorophyll a concentration was not significantly affected by warming, however in summer, autumn and winter it was significantly higher in mesocosms receiving intermediate OM levels (July–Feb DOC concentrations 2–6 mg L⁻¹). Summer cyanobacterial blooms were highest in intermediate, and lowest in the highest OM treatments. OM concentration also influenced total macroinvertebrate abundance which was greater in spring and summer in mesocosms with intermediate and high OM. Fish abundance was not significantly affected by OM concentration, but abundance was greater in ambient (55 fish subsample⁻¹) compared to heated mesocosms (17 fish subsample⁻¹) and maximum abundance occurred two weeks later compared to heated mesocosms. The results suggest that changes in OM may have a greater effect on shallow lakes than temperature and that phytoplankton, especially cyanobacteria, benefit from intermediate OM concentrations, therefore, nuisance algal blooms might increase in relatively clear shallow eutrophic lakes where DOC concentrations increase.
图文摘要:

22792. 题目: Long-term effects of crop succession, soil tillage and climate on wheat yield and soil properties
文章编号: N19050102
期刊: Soil and Tillage Research
作者: Paula Sanginés de Cárcer, Sokrat Sinaj, Mathieu Santonja, Dario Fossati, Bernard Jeangros
更新时间: 2019-05-01
摘要: Climate change is increasing crop losses and yield variability with impacts for global food security. In this context, conservation agriculture appears as a potential solution to maintain crop productivity, soil fertility and environmental sustainability. Therefore, understanding the combined effects of soil tillage and crop succession over a long period is of primary interest. In this study, we analyzed data from a 50 year long-term field experiment to assess (i) the change of climatic parameters, wheat yield and soil organic carbon (SOC) content; (ii) the combined effects of crop succession (monoculture vs. crop rotation) and soil tillage system (minimum tillage vs. plough) on wheat yield, SOC content and other soil properties at three soil depths (0–10, 10–20 and 20–50 cm); and (iii) the relative contributions of climatic parameters, wheat phenology and agricultural practices on wheat yield variability. Wheat yield was 16% higher in crop rotation compared to monoculture, while soil tillage system had no significant effect on wheat yield during the period 1977–2016. Despite a SOC content decline over time, which was especially marked during the first ten years of the study, SOC content was 7% higher in the minimum tillage treatment compared to the plough treatment, while crop rotation had no significant effect. In 2016, after 50 years of experimentation, both crop succession and soil tillage systems influenced soil properties. Over the 50-year period, the climatic conditions around the heading phase explained 22% of yield variability, while 18% of this variability was explained by crop succession and 6% by the growing degree days until heading stage. In a context of conservation agriculture promotion, our long-term field experiment provides key evidence that the combination of both minimum soil tillage and crop rotation improves soil fertility and crop productivity.
图文摘要:

22793. 题目: Effect of microbial activity and microbial community structure on the formation of dissolved organic nitrogen (DON) and bioavailable DON driven by low temperatures
文章编号: N19050101
期刊: Water Research
作者: Kewei Liao, Haidong Hu, Sijia Ma, Hongqiang Ren
更新时间: 2019-05-01
摘要: Dissolved organic nitrogen (DON) formed by microbial metabolism in wastewater treatment processes adversely impacts wastewater reuse and receiving waters quality, and microbial metabolism is greatly influenced by temperatures. However, little is known about the effect of microorganisms on DON and bioavailable DON (ABDON) formation under low temperatures. In this study, six reactors were operated at low (8 °C and 15 °C) and room (25 °C) temperatures to evaluate the relationship between microbial activity, microbial communities, and DON and ABDON. Results showed that DON and ABDON concentrations significantly increased at low temperatures (p < 0.05, t-test). DON formation was significantly correlated to microbial activity only, with adenosine triphosphate (negative, r = -0.64) and polysaccharide (positive, r = 0.61) as key indicators; however, ABDON formation was influenced by both microbial activity (polysaccharide > triphenyltetrazolium chloride-dehydrogenases > adenosine triphosphate) and microbial community structure. Short-term tests using the biomass from six reactors were performed at room temperature to further validate the relationship. The distinct differences between these results provide a basis for different strategies on reducing effluent DON and ABDON under low temperatures.
图文摘要:

22794. 题目: Historical Black Carbon Reconstruction from the Lake Sediments of the Himalayan–Tibetan Plateau
文章编号: N19043004
期刊: Environmental Science & Technology
作者: Bigyan Neupane, Shichang Kang, Pengfei Chen, Yulan Zhang, Kirpa Ram, Dipesh Rupakheti, Lekhendra Tripathee, Chhatra Mani Sharma, Zhiyuan Cong, Chaoliu Li, Juzhi Hou, Min Xu, Poonam Thapa
更新时间: 2019-04-30
摘要: Black carbon (BC) is one of the major drivers of climate change, and its measurement in different environment is crucial for the better understanding of long-term trends in the Himalayan–Tibetan Plateau (HTP) as climate warming has intensified in the region. We present the measurement of BC concentration from six lake sediments in the HTP to reconstruct historical BC deposition since the pre-industrial era. Our results show an increasing trend of BC concurrent with increased anthropogenic emission patterns after the commencement of the industrialization era during the 1950s. Also, sedimentation rates and glacier melt strengthening influenced the total input of BC into the lake. Source identification, based on the char and soot composition of BC, suggests biomass-burning emissions as a major contributor to BC, which is further corroborated by open-fire occurrence events in the region. The increasing BC trend continues to recent years, indicating increasing BC emissions, mainly from South Asia.
图文摘要:

22795. 题目: Assisted phytoremediation of a co-contaminated soil with biochar amendment: Contaminant removals and bacterial community properties
文章编号: N19043003
期刊: Geoderma
作者: Manyun Zhang, Jun Wang, Shahla Hosseini Bai, Yaling Zhang, Ying Teng, Zhihong Xu
更新时间: 2019-04-30
摘要: There are growing trends of combined contaminations in agricultural soils, and therefore it is urgently needed to remediate contaminated soils with eco-friendly approaches. This study aimed to evaluate the effects of Medicago sativa L. (alfalfa) planting, alone or together with biochar additions, on contaminant removals and bacterial properties in an agricultural soil contaminated by heavy metal and organic fungicide. The treatments in this study included: the control (CK), alfalfa planting (AP), alfalfa planting +1.5% biochar addition (w/w) (AP + 1.5B), alfalfa planting +3.0% biochar addition (AP + 3.0B), and alfalfa planting +6.0% biochar addition (AP + 6.0B). Relative to the alfalfa planting only, extra biochar additions increased alfalfa biomass and heavy metal cadmium (Cd) phytoextraction. The alfalfa planting, alone or together with biochar additions, significantly decreased soil iprodione concentrations. After 90 days of remediation, bacterial 16S rRNA gene abundances of the AP, AP + 1.5B, AP + 3.0B and AP + 6.0B treatments were 1.69, 3.84, 3.34 and 3.13 times as great as that obtained from the CK treatment, respectively. The AP + 1.5B treatment had the highest richness estimators and Shannon diversity index, but the AP + 6.0B treatment had the lowest invsimpson diversity index among the five treatments. The relative abundances of Bacteroidetes and Nitrospirae were enhanced by the alfalfa phytoremediation, alone or together with biochar additions. Our results suggest that the alfalfa has promising potentials in the remediation of co-contaminated soil and in the increases of soil bacterial biomass and community diversity. Simultaneously, biochar is beneficial to enhance Cd phytoextraction, however, biochar addition rate would need to be optimized.
图文摘要:

22796. 题目: Effect of biochars on the bioavailability of cadmium and di-(2-ethylhexyl) phthalate to Brassica chinensis L. in contaminated soils
文章编号: N19043002
期刊: Science of The Total Environment
作者: Hanbo Chen, Xing Yang, Gerty Gielen, Sanchita Mandal, Song Xu, Jia Guo, Sabry M. Shaheen, Jörg Rinklebe, Lei Che, Hailong Wang
更新时间: 2019-04-30
摘要: Soil co-contamination of potentially toxic elements (PTEs) and phthalate esters has become prominent due to its potential adverse effect on human food supply. There is limited information on using wood- and animal-derived biochars for the remediation of co-contaminated soils. Therefore, a pot experiment was conducted using Brassica chinensis L. as a bio-indicator plant to investigate the effect of P. orientalis biochar and pig biochar application on the bioavailability of cadmium (Cd) and di-(2-ethylhexyl) phthalate (DEHP) and on plant physiological parameters (malondialdehyde, proline and soluble sugars). Biochar materials were applied to two soils containing low (LOC) and high (HOC) organic carbon content at rates of 0, 0.5, 1, 2, and 4%. To better understand the influence of biochar, physicochemical properties and X-ray diffraction (XRD), energy dispersive X-ray spectrometry (EDS), Fourier transform-infrared spectrometry (FTIR), scanning electron microscopy (SEM) were characterized. Biochar application increased soil pH, organic carbon content, and available phosphorus content. Increasing biochar application rates decreased DTPA-extractable Cd and extractable DEHP concentrations in both soils. Biochar application reduced the plant uptake of both Cd and DEHP from co-contaminated soils; the maximum reduction of Cd (92.7%) and DEHP (52.0%) was observed in 2% pig biochar-treated LOC soil. The responses of plant physiological parameters to increased biochar applications indicated that less Cd and DEHP were taken up by plants. Pig biochar was more effective (P < 0.05) at reducing the bioavailability of Cd and DEHP in both soils than P. orientalis biochar; therefore, pig biochar had greater potential for improving the quality of the crop. However, the highest application rate (4%) of pig biochar restricted plant seed germination. Key factors influencing the bioavailability of Cd and DEHP in soils were soil organic carbon content, biochar properties (such as surface alkalinity, available phosphorus content and ash content) and biochar application rates.
图文摘要:

22797. 题目: Nitrogen mineralization and microbial biomass carbon and nitrogen in response to co-application of biochar and paper mill biosolids
文章编号: N19043001
期刊: Applied Soil Ecology
作者: Eric Manirakiza, Noura Ziadi, Mervin St. Luce, Chantal Hamel, Hani Antoun, Antoine Karam
更新时间: 2019-04-30
摘要: Adding biochar to paper mill biosolids (PB) amendments may affect PB mineralization rate and nitrogen (N) availability. The objective of this 224-day incubation study was to evaluate the effect of amending two PB types varying in carbon (C)/N ratio (PB1, C/N = 24; and PB2, C/N = 13) with three rates (0%, 2%, and 5%) of pine (Pinus strobus L.) biochar produced at 700 °C on the dynamics of total C, total N, mineral N, N mineralization rate, and microbial biomass C (MBC) and N (MBN) in two agricultural soils (Kamouraska clay and St-Antoine sandy-loam). Two reference treatments were also included, namely, mineral fertilization and unamended soil. Total soil C concentration remained stable over the incubation period, whereas a decrease in total soil N was observed in both soils. In comparison with the unamended soil, the application of PB significantly increased total N, NH₄-N, NO₃-N, net mineralized N, applied N mineralization rate, and MBC in both soils. In comparison with the application of PB alone, biochar addition increased total C and MBC but decreased NH₄-N, NO₃-N, net N mineralization, and applied N mineralization rate in both soils. The co-application of biochar and PB1 resulted in the sequestration of mineral N released, which was more pronounced in the Kamouraska clay soil. The co-application of biochar and PB2 resulted in moderate release of mineral N. This study showed that the co-application of biochar and PB can benefit agricultural soils by improving NO₃-N retention in agroecosystems while increasing organic matter and promoting microbial biomass.

22798. 题目: Spatial distribution and controlling factors of heavy metals in soils from Puding Karst Critical Zone Observatory, southwest China
文章编号: N19042907
期刊: Environmental Earth Sciences
作者: Qian Zhang, Guilin Han, Man Liu, Tao Liang
更新时间: 2019-04-29
摘要: Soil profile samples under different land-use types were collected at the Puding Karst Critical Zone Observatory to investigate the composition, distribution and controlling factors of heavy metals. The heavy metal contents of Cr, Mn, Fe, Ni, Cu, Zn, Cd and Pb were determined, and their relationships to soil properties were examined. The Mn, Zn, Cd and Pb contents were larger in the topsoil than the deeper layer in all land use. In secondary forest land, the Cr, Fe, Ni and Cu contents in the topsoil were lower than in the deeper layer; however, all eight heavy metal contents were enriched in the topsoil under cropland. The results showed soil organic carbon played a fundamental role in controlling of Cd, while it showed negative relationship with Cr, Fe, Ni and Cu. Soil pH was positively associated with Ni and Cu. The Cr, Fe, Ni and Cu contents were significantly correlated to proportion of micro-aggregates, while the Cd and Pb contents showed a positive correlation with proportion of macro-aggregates. According to principal component analysis, the Cr, Fe, Ni and Cu contents might be affected by soil organic matter; however, the Mn, Zn and Pb contents might be influenced by atmospheric heavy metal deposition, and the Cd content might be controlled by both organic matter and atmospheric deposition. The geoaccumulation index and enrichment factor were calculated to assess the pollution level of soils, and the results showed that most of the selected heavy metals in soils may not be present at sufficient levels for contamination, and Mn and Fe were not from a pollution source and might come from natural weathering processes. This research will help researchers make strategic decisions about food security in the choice of agricultural land.

22799. 题目: Modification of biochar properties using CO₂
文章编号: N19042906
期刊: Chemical Engineering Journal
作者: Youkwan Kim, Jeong-Ik Ok, Meththika Vithanage, Young-Kwon Park, Jechan Lee, Eilhann E. Kwon
更新时间: 2019-04-29
摘要: Biochar is widely used for various environmental remediation strategies such as soil amendment because of its intrinsic carbon negativity and porosity. Biochar is a charcoal-like material produced via pyrolysis of biomass. To determine an effective method for modification of the porosity and morphology of biochar and establishment of a more sustainable pyrolysis platform for biomass valorization, this study used CO₂ as a reactive gas medium in the biomass pyrolysis process. This study placed emphasis on elucidating the role of CO₂ in the production of biochar from different types of biomass, such as cellulose, xylan, lignin, grass, and oak wood. The surface area and porosity of biochar were strongly related to the type of biomass. Under comparable pyrolysis conditions, the surface area of biochar decreased in the following order: cellulose > xylan > lignin ∼ oak wood > grass. The use of CO₂ as the gas medium in biomass pyrolysis affected the surface area and porosity of biochar samples derived from biomass feedstock. For instance, the surface area and total pore volume of the oak-wood-derived biochar produced in the CO₂ environment were twice those produced in the N₂ environment. Given that the increases in the biochar surface area and porosity were attributed to the enhanced release of volatile organic compounds (VOCs) from biomass, CO₂ may have enhanced VOC release (removal) during pyrolysis. Therefore, the use of CO₂ in a pyrolysis platform is expected to be a strategic approach for biomass valorization.

22800. 题目: Adsorption and degradation in the removal of nonylphenol from water by cells immobilized on biochar
文章编号: N19042905
期刊: Chemosphere
作者: Liping Lou, Huang Qian, Yiling Lou, Jingrang Lu, Baolan Hu, Qi Lin
更新时间: 2019-04-29
摘要: To investigate the role of adsorption by biochar and biodegradation by bacteria in the wastewater treatment system of microorganisms immobilized on biochar, Nonylphenol (NP) removal (adsorption + degradation) rates and degradation rates from water by NP degrading bacteria immobilized on bamboo charcoal (BC) and wood charcoal (WC) were examined in a short-term and long-term. Results showed that cells immobilized on different biochar had different NP removal effects, and cells immobilized on bamboo charcoal (I-BC) was better. After eight rounds of long-term reuse, the cumulative removal rate and the degradation rate of NP in water by I-BC were 93.95% and 41.86%, respectively, significantly higher than those of cells immobilized on wood charcoal (69.60%, 22.78%) and free cells (64.79%, 19.49%) (P < 0.01). The rise in the ratio of the degradation rate to the removal rate indicated that the long-term NP removal effect is more dependent on biodegradation. The amount of residual NP in I-BC still accounted for about 50%, indicating that the secondary pollution in the disposal of carrier could not be ignored. In addition, promotion effect of biochar on microorganisms were observed by SEM, quantitative PCR and 16S rRNA. Pseudomonas, Achromobacter, Ochrobactrum and Stenotrophomonas were predominant bacteria for NP degradation. The addition of biochar (especially bamboo charcoal) also effectively delayed the transformation of their community structure.
图文摘要: