141. 题目: Purification mechanism of city tail water by constructed wetland substrate with NaOH-modified corn straw biochar
期刊: Ecotoxicology and Environmental Safety
作者: Hanxi Wang, Xinyu Wang, Haowen Teng, Jianling Xu, Lianxi Sheng
摘要: The pollution of corn straw to the environment had attracted much attention. The preparation and alkali modification of corn straw biochar as the constructed wetland (CW) substrate was conducive to solving the environment pollution caused by straw and improving the purification effect of CW. The NaOH modification mechanism of corn straw biochar was analyzed by measuring the surface morphology, element content, specific surface area (SSA), pore volume, crystal structure, surface functional groups and CO2 adsorption. Biochar prepared under relatively optimal NaOH-modified conditions was used as the vertical flow CW substrate to treat city tail water. The results showed that controlling the modification condition of NaOH (< 1.0 mol·L−1, ≤ 24 h) was conducive to prevent the biochar structure destruction and C element reduction. The SSA and pore volume of NaOH (0.1 mol·L−1) modified biochar are 360 m2·g−1 and 0.109 cm3·g−1, respectively. The biochar adsorption for CO2 conformed to the Langmuir and Freundlich isothermal adsorption theoretical model (R2 > 0.9). The maximum adsorption capacity of CO2 by modified biochar with NaOH (0.1 mol·L−1) was 64.516 cm3·g−1 and increased by 10.3%. The city tail water treated by CW with plants showed that the removal rates of ammonia nitrogen, total nitrogen and nitrate nitrogen reached about 90%. The research results improved the utilization value of straw, realized straw carbon sequestration and promoted the progress of CW technology.
142. 题目: The fate of microplastics and organic matter leaching behavior during chlorination
作者: Tao Lin, Jinmin Su
摘要: As an emerging persistent pollutant, microplastics (MPs) have been detected in the drinking water system and its potential risk in the presence of disinfectants has received little attention. This work aimed to investigate the changes in MPs properties and the organic matter leaching behavior of MPs during chlorination. Physical and chemical changes of the chlorinated MPs were detectable by scanning electron microscope, Micro-Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). Polystyrene (PS) was less resistant to chlorination than polyethylene (PE), indicated by changes in Raman peaks and O/C ratio of the XPS spectrum. Organic matter leaching behavior of MPs was explored by dissolved organic carbon (DOC) determination and disinfection byproducts formation potential measurement. The results demonstrated the stimulating effect of chlorination on the organic matters leaching from MPs, with the total leached DOC accounting for ∼0.3‰–0.5‰ of the MPs mass. The leached organic matters exhibited an appreciable potential to form trihalomethanes (THMs) and haloacetonitriles (HANs). The formation potential of THMs and HANs were 54.43–185.08 μg/mg C and 3.65–11.83 μg/mg C, respectively. Compared to PE, organic matter leaching behavior during chlorination was more obvious for PS. This study provides insights into the fate of chlorinated microplastics and the possible risk of organic matters leached from MPs to form disinfection byproducts during chlorination.
143. 题目: Quantitative evaluation of the synergistic effect of biochar and plants on immobilization of Pb
期刊: Journal of Environmental Management
作者: Ping Sun, Youyuan Chen, Jiaxin Liu, Shuang Lu, Jiameng Guo, Zhiming Zhang, Xilai Zheng
摘要: Biochar and plant cooperation in remediation of heavy metal contaminated soil is effective and important, but there still have knowledge gaps of synergistic effect between the two and the synergistic pathway has not been clarified. We prepared the Enteromorpha prolifera biochar at 400 °C and 600 °C (denoted as BC400 and BC600). The Pb fractions changes in soil and Pb toxicity in Brassica juncea were investigated by adding 30 g kg−1 biochar to soil containing 1200 mg kg−1 Pb in a pot experiment. There was a significant synergistic effect between biochar and plants on Pb immobilization in soil, according to the “E > 0” of Pb fractions in the interaction equation. Pb immobilization rates of biochar-plant treatments (BJBC4 and BJBC6) were 12.47% and 11.38% higher than biochar treatment (BC4, BC6), and 17.66% and 16.28% plant treatment (BJ). BJBC4 had a better immobilization effect than BJBC6. Biochar alleviated the phytotoxicity of Pb by increasing the antioxidant enzymes activities of plants. These results indicated two synergistic pathways: (1) The high pH and oxygen-containing functional groups of biochar could immobilize Pb through ion exchange, precipitation, or complexation. (2) Biochar enhanced the activity of the antioxidant enzyme system in plants thus improving the Pb tolerance of plants. Statistical analysis methods such as the partial least squares path modeling (PLS-PM) also confirmed the pathways. In a word, clear synergistic effects and pathways could guide the application of biochar and plants in Pb-contaminated soil.
144. 题目: n-C27 Predominance and 13C enrichment by bicarbonate assimilation of race A of Botryococcus braunii in Chinese Maoming oilshales
期刊: Chemical Geology
作者: Jing Liao, Qiao Feng, Hong Lu, Guoying Sheng, Ping'an Peng, Chang Samuel Hsu
摘要: In Maoming oilshales, the presence of races B and L of Botryococcus braunii (B. braunii) was confirmed by the detection of botryococcanes and C40 lycopanes and their derivatives. However, there were no specific biomarkers for race A of B. braunii. The contribution of race A of B. braunii has been implied by the distribution of non-specific n-alkanes with an odd carbon-number preference and a predominance of n-C27. However, confirmation of its contribution to oilshales has been lacking until now. We found that n-C27 is a dominant n-alkane in most Maoming samples which exhibits a positive δ13C excursion (approximately 2–3‰) compared to other homologues. In addition, the extremely heavy δ13C values of botryococcanes (−6.0‰ to −8.5‰) are rationalized to reflect bicarbonate assimilation in race B of B. braunii. The positive excursion of the δ13C values of n-C27 extracted from the same samples could be attributed to bicarbonate assimilation by race A in a similar manner. Bicarbonate assimilation by race A would also explain the isotopic enrichment of n-C14 ~ n-C33 alkanes in the range of −20.1‰ to −26.1‰. They are close to the values of some higher plant sources (C4 plant) and largely different than that of the reported algal n-alkanes (<−30.6‰). The bicarbonate consumption mechanism utilized by both races A and B of B. braunii in Maoming oilshales was triggered by the sharp decrease in pCO2 during the Late Eocene period, recorded globally at the Eocene-Oligocene transition. The presence of race A of B. braunii in most of Maoming sediments indicates that it was wide spread and populated in Maoming Basin over a long period of time, serving as the main biological source material of oilshales on a large scale.
145. 题目: Microwave-assisted pyrolysis derived biochar for volatile organic compounds treatment: characteristics and adsorption performance
期刊: Bioresource Technology
作者: Wei Xiang, Xueyang Zhang, Chengcheng Cao, Guixiang Quan, Min Wang, Andrew R. Zimmerman, Bin Gao
摘要: Biochar derived from corn stalk doping with activated carbon was produced by microwave-assisted pyrolysis and applied to sorb volatile organic compounds (VOCs: benzene and o-xylene). Specific surface area (SSA), total pore volume (TPV) and micropore volume (MV) of microwave biochar increased with increasing microwave power with the maximum values 325.2 m2·g-1, 0.181 mL·g-1 and 0.1420 mL·g-1, respectively. Adsorption capacities of benzene and o-xylene on microwave biochar ranged 6.82 - 54.75 mg·g-1 and 7.43 - 48.73 mg·g-1, which were separate positively related with SSA, TPV, and MV. Benzene adsorption was mainly dominated by surface interaction and partition mechanisms, while o-xylene adsorption was governed by pore filling. The adsorption capacities of microwave biochar for benzene and o-xylene decreased by only 0.30% and 0.99% on the 5th cycle that illustrated the reasonably good reusability of microwave biochar. The results of this research demonstrate that microwave biochar is a promising adsorbent for VOCs removal.
146. 题目: Catalytic pyrolysis of lotus leaves for producing nitrogen self-doping layered graphitic biochar: Performance and mechanism for peroxydisulfate activation
作者: Fan Liu, Jing Ding, Guanshu Zhao, Qingliang Zhao, Kun Wang, Guangzhi Wang, Qingwei Gao
摘要: In this study, nitrogen self-doping layered graphitic biochar (Na-BC900) was prepared by catalytic pyrolysis of lotus leaves at 900 °C, in the presence of NaCl catalyst, for peroxydisulfate (PDS) activation and sulfamethoxazole (SMX) degradation. NaCl as catalysts played a crucial part in the preparation of Na-BC900 and could be reused. The SMX degradation rate in Na-BC900/PDS system was 12 times higher than that in un-modified biochar (BC900)/PDS system. The excellent performance of Na-BC900 for PDS activation was attributed to its large specific surface areas (SSAs), the enhanced graphitization structure and the high graphitic N content. The quenching and electrochemical experiments, electron paramagnetic resonance (EPR) studies inferred that the radicals included SO4•-, •OH, O2•- and the non-radical processes were driven by 1O2 and biochar mediated electron migration. Both radical and non-radical mechanisms contributed to the removal of SMX. Additionally, this catalytic pyrolysis strategy was clarified to be scalable, which can be applied to produce multiple biomass-based biochar catalysts for restoration of polluted water bodies.
147. 题目: Spectral characteristics of dissolved organic carbon (DOC) derived from biomass pyrolysis: Biochar-derived DOC versus smoke-derived DOC, and their differences from natural DOC
作者: Huiying Zhang, Wei Qian, Liang Wu, Shuhan Yu, Ran Wei, Weifeng Chen, Jinzhi Ni
摘要: Biochar-derived dissolved organic carbon (BDOC) and smoke-derived dissolved organic carbon (SDOC) are two different biomass-pyrogenic DOCs. They inevitably enter soil and water, then potentially pose different impacts on the chemistry of these media. This study systemically investigated the emissions and spectral characteristics of BDOC and SDOC as well as their differences from natural DOC. The results showed that the emission of SDOC was 1–3 orders of magnitude greater than that of BDOC after biomass pyrolysis. UV–vis spectra indicated that BDOC had higher aromaticity and molecular weight as well as lower polarity than SDOC. The two-dimensional correlation infrared spectrum (2D-PCIS) matrix indicated that BDOC contained more chemical groups with stronger temperature-dependence than SDOC. Fluorescence EEM-PARAFAC analysis showed that BDOC was dominated by macromolecular humic-like substances, while SDOC was primarily composed of small molecules of aromatic protein/polyphenols-like compounds. The fluorescence indicators including humification index (HIX) (0.08–0.76) and biological index (BIX) (1.18–1.72) of SDOC were significantly different from those of BDOC (HIX: 1.64–12.68, and BIX: 0.17–1.62). The higher BIX and more small molecules of aromatic protein/polyphenols-like compounds indicated SDOC had potentially higher bioavailability and turnover rate in the environment than BDOC. Furthermore, the UV–vis spectral indicator (S275-295) and fluorescence spectral indicators (HIX, and BIX) of BDOC were equivalent to those of natural DOC, whereas these indicators of SDOC were significantly different from those of natural DOC. This study demonstrated that BDOC and SDOC had significantly different components and properties and they might present different environmental behaviors and effects.
148. 题目: Synthesis of biochar@α-Fe2O3@Shewanella loihica complex for remediation of soil contaminated by hexavalent chromium: Optimization of conditions and mechanism
作者: Dexun Zou, Jingjing Tong, Chenyu Feng, Yang Wang, Xinxin Li, Xusheng Zheng, Xuebo Wang, Yanping Liu
摘要: The reduction of hexavalent chromium combined with the process of dissimilatory iron reduction is an important strategy for microbial remediation of chromium-contaminated soil. However, its applicability is limited by the slow speed of bacterial bioreduction and the toxic effect of heavy metals on bacteria. Here, biochar (BC) was used as a substrate and was loaded with iron oxide in the form of hematite and Shewanella loihica to synthesize a BC@α-Fe2O3@S. loihica complex and thus achieve combined microbial–chemical remediation. After optimization by a Box–Behnken design, the optimal dosages of the complex, humic acid (as an electron shuttle), and sodium lactate (as an electron donor) were found to be 1.38 mL/g, 33.94 mg/g, and 12.95%, respectively. The Cr(VI) reduction rate in soil contaminated with 1000 mg/kg Cr(VI) reached 98.26%, and remediation could be achieved within 7 days. Characterization of the BC@α-Fe2O3@S. loihica complex before and after it was used for remediation by energy-dispersive X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy proved that the oxygen-containing functional groups and aromatic compounds on the surface of the BC participated in the adsorption and reduction of Cr(VI) and that the loaded hematite particles were fully utilized by microorganisms. Therefore, the BC@α-Fe2O3@S. loihica complex has great potential for the remediation of Cr(VI)-contaminated soil.
149. 题目: Passivation of lead and cerium in soil facilitated by biochar-supported phosphate-doped ferrihydrite: Mechanisms and microbial community evolution
期刊: Journal of Hazardous Materials
作者: Hui Li, Qun Jiang, Ruizhen Li, Bo Zhang, Jiaxing Zhang, Ying Zhang
摘要: The massive exploitation and application of heavy metals and rare earth elements (REEs) lead to their exceeding the standard in soil. Herein, a new type of biochar supported phosphorus doped ferrihydrite (P-FH@BC) has been designed and enhance passivation of Pb and Ce in soil. SEM images of P-FH@BC showed P-FH nanoparticles adhered to the natural cavity and large pore diameter on the surface of biochar, which greatly avoided the agglomeration of nanoparticles. The residual state of lead or cerium increased 161.4% or 43.9% by adding 3% P-FH@BC after 90 days of incubation in 500mg/kg lead or cerium simulated contaminated soil. The passivation of cerium by P-FH@BC is obviously inhibited with the coexistence of lead. The results of P-FH@BC magnetically separated from the soil characterization indicate that complexation, co-precipitation and the formation of secondary minerals mainly contribute to the high efficiency passivation ability of P-FH@BC for lead and cerium. By changing the addition of P-FH@BC, the soil pH can be adjusted and the soil organic matter and P contents can be improved. Moreover, P-FH@BC is an environmentally friendly material without ecotoxicity. And bacterial richness and diversity in soil were improved after passivation of Pb and Ce by adding P-FH@BC.
150. 题目: Insights into graphene oxide/ferrihydrite adsorption as pretreatment during ultrafiltration: membrane fouling mitigation and disinfection by-product control
期刊: Journal of Hazardous Materials
作者: Zhan Wu, Ying Zhang, Jiang Jiazheng, Jian Pu, Satoshi Takizawa, Li-an Hou, Yu Yang
摘要: In this study, a novel adsorbent of graphene oxide (GO) incorporated ferrihydrite (FH) was fabricated and integrated with ultrafiltration (UF) to remove natural organic matter (NOM), the crucial cause of membrane fouling and major precursor of disinfection by-products (DBPs). Compared with FH and powdered activated carbon, GO/FH exhibited superior removal for high molecular weight (HMW) humic- and fulvic-like substances and low molecular weight (LMW) protein. The cake layer formed by GO/FH alleviated the deposition of NOM on membrane surface or inside membrane pores. Therefore, GO/FH reduced 89% and 95% total fouling resistance and irreversible membrane resistance, respectively, together with the lowest increment of transmembrane pressure. Pearson correlation analysis indicated that DOC, rather than specific ultraviolet absorbance (SUVA) and UV254, was significantly correlated to the formation of trihalomethanes (THMs) and haloacetic acids (HAAs) when SUVA was below 4L/mg-C.m. Whilst the HMW NOM (1-20kDa) was highly related to dibromochloromethane (DBCM) (r = 0.98-1), the LMW fraction (< 1kDa) was correlated with dibromochloromethane (TCAA) and dichloroacetic acid (DCAA) (r = 0.88-0.98). Inspiringly, GO/FH-UF reduced 90% of carbonaceous DBPs, the concentrations of which well met the WHO Guidelines. In summary, GO/FH-UF substantially alleviated membrane fouling and dramatically reduced DBP formation potential.
151. 题目: Combined remediation effects of biochar, zeolite and humus on Cd-contaminated weakly alkaline soils in wheat farmland
作者: Weihua Wang, Tao Lu, Lihu Liu, Xiong Yang, Xuanzhen Li, Guohong Qiu
摘要: Threats posed by Cd-contaminated arable soils to food security have attracted increasing attention. The combination of organic and inorganic amendments has been extensively applied to immobilize Cd in paddy soils. However, the regulatory mechanism of Cd fractionation under these combined amendments and the effect on wheat Cd accumulation remain unclear in upland soils. In this work, different combinations of organic and inorganic amendments were prepared with biochar, zeolite and humus, and the Cd-immobilization mechanism was also investigated in field experiments. The results demonstrated that the mixture of biochar, zeolite and humus had excellent Cd immobilization performance in highly Cd-contaminated (4.26 ± 1.25 mg kg−1) weakly alkaline soils, resulting in 76.5–84.8% decreases in soil available Cd. The contribution of single components to Cd immobilization in the combined amendment follows the order of humus > biochar > zeolite. The combined amendment converted the acid soluble Cd to the Cd bound to the reducible fraction with higher stability, thereby decreasing Cd bioavailability. The maximum Cd decrease rate in wheat roots, straw and grains could reach 68.2%, 45.0% and 59.3%, respectively, and the Cd content in grains (0.098 mg kg−1) was lower than the food security standards of China (0.1 mg kg−1). Wheat planting for two successive years in a large-scale field further verified the superior Cd immobilization performance and stability of the combined amendment in moderately to slightly Cd-contaminated soil. The present study provides references for the remediation of Cd-contaminated weakly alkaline upland soils and certain guidance for safe food production.
152. 题目: Reduced pH is the primary factor promoting humic acid formation during hyperthermophilic pretreatment composting
期刊: Journal of Environmental Management
作者: Yun Cao, Junyu Gu, Jing Zhang, Bao Chen, Yueding Xu, Dongyang Liu, Hangwei Hu, Hongying Huang
摘要: Hyperthermophilic pretreatment composting (HPC) has the advantages of enhanced composting efficiency and accelerated humic substance (HS) over conventional composting (CC). However, the mechanisms towards the accelerated humification process by HPC are still not clear. By means of sterilization technology, the roles of abiotic and biotic components on the formation of HS can be distinguished. The study investigated the humification degree and the succession of microbial community during HPC of pig manure. The mechanisms underlying the accelerated humification by HPC was identified using gamma sterilization. Results showed that HS content increased significantly by 13.72% in HPC and 29.93% in sterilized HPC inoculated with 1% CC (HPC_I), compared with 8.76% increase in CC and 7.12% increase in sterilized CC inoculated with 1% HPC during composting (CC_I). Compared with CC and CC_I, stronger intensities of HA-like and fulvic acid-like components were observed in HPC and HPC_I. Results showed that physicochemical properties, especially pH, were the key factors in accelerating the humification in HPC, while both physicochemical properties and microbial community contributed to the HA formation in CC. The study contributed to a better understanding of the mechanism towards the accelerated humification degree in HPC.
153. 题目: Boosting active sites of protogenetic sludge-based biochar by boron doping for electro-Fenton degradation towards emerging organic contaminants
期刊: Separation and Purification Technology
作者: Luyi Xing, Jia Wei, Yifei Zhang, Mengdie Xu, Guoping Pan, Jiamei Li, Jun Li, Yanan Li
摘要: There has been extensive research on biochar materials in the field of adsorption, catalysis, etc. Hereon, we reported a gentle synthesis of electrode by abundant biomass of municipal sludge and cheap precursor of boric acid as carbon source and boron source. Experimental results demonstrated that a small amount of boron doping had a profound impact on the elemental composition and active sites of sludge-based biochar significantly, resulting the improvement EF activity for sulfamerazine (SMR) removal. Under the optimal reaction conditions, including initial pH, added divalent iron, applied current and air flow, 95.12% of SMR could be removed in 180 min in EF system. It was confirmed that hydroxyl radical (·OH) and superoxide radical (·O2-) were the primary active substances for SMR degradation. The effect experiments of various ions, types of wastewater and pollutants were carried out and the stability experiments were conducted for eight cycles without significant efficiency loss, which proved the exceptional applicability and reusability of the gained boron doped sludge-based biochar electrode BSBC-E. These functions of boron-doped sludge-based biochar cathode could be a promising material for emerging organic contaminants remediation.
154. 题目: Contribution of different mechanisms to Pb2+ and Cd2+ sorption on magnetic wheat straw biochars: impact of pyrolysis temperature and DOM in biochar
期刊: Journal of Environmental Chemical Engineering
作者: Haofei Gong, Jie Chi
摘要: This work quantitatively studied the sorption of Pb2+ and Cd2+ on magnetic biochars (MBCs) pyrolyzed at temperatures of 300, 500 and 700 °C and the effect of biochar-derived dissolved organic matter (BDOM) on Pb2+ and Cd2+ sorption. Surface characteristics of the MBCs before and after sorption were analyzed using Boehm titration and various spectroscopic techniques. For Pb2+, with increasing pyrolysis temperature, the sorption amounts by precipitation and coordination with π electrons increased from 63.5 to 109.3mg/g and from 27.0 to 84.9mg/g, respectively. While the sorption amount by complexation decreased from 34.5 to 16.5mg/g. The contribution of precipitation (45.9%-52.5%) and coordination with π electrons (19.5%-39.1%) increased with increasing pyrolysis temperature, while contribution of complexation (7.6%-24.9%) decreased. Increased ash content and aromaticity with pyrolysis temperature played the key roles in the change of Pb2+ sorption. The ion exchange and precipitation mechanisms dominated Cd2+ sorption on MBCs. Their respective sorption amounts were in the ranges of 5.08-10.36 and 1.31-9.82mg/g, accounting for 48.8%-72.5% and 18.7%-46.3% of the total sorption, respectively. The change of ion-exchangeable sites on minerals with pyrolysis temperature is the main reason influencing the sorption via ion exchange for Cd2+. Unlike MBC500 and MBC700, removing BDOM from pristine biochar of MBC300 enhanced the total amounts of Pb2+ and Cd2+ sorption by 1.2 and 3.6 times, respectively, which was attributed to the enhanced sorption via ion exchange, precipitation and complexation for Pb2+ and enhanced sorption via ion exchange and precipitation for Cd2+. Therefore, the DOM-removed low-temperature MBC is a promising sorbent for treating heavy metal polluted waters.
155. 题目: A terrestrial‐aquatic model reveals cross‐scale interactions regulate lateral dissolved organic carbon transport from terrestrial ecosystems
期刊: Journal of Geophysical Research: Biogeosciences
作者: Ceara J. Talbot, Diogo Bolster, David Medvigy, Stuart E. Jones
摘要: Lateral carbon transport (LCT), the flux of terrestrial C transported to aquatic ecosystems, displaces carbon (C) across the terrestrial-aquatic continuum and is on the same order of magnitude as terrestrial net ecosystem production. However, few continental scale C models include LCT or the C-hydrology linkages necessary for modeling LCT. Those that do exist, borrow processes and conceptual understanding from watershed scale models, assuming that large- and small-scale drivers of LCT are the same. We develop a conceptual framework of LCT, which focuses on lateral dissolved organic carbon (DOC) transport (LCT-DOC), and operationalize it with a coupled terrestrial-aquatic C and hydrology model. After comparing our model LCT-DOC to previous estimates derived from a summation of landscape scale fluxes for the Contiguous U.S, we use model experiments to partition the importance of LCT-DOC drivers including total annual precipitation, air temperature, and plant traits, which interact across regional and local scales. We find that climate is the strongest driver of LCT-DOC, where LCT-DOC is positively related to precipitation but inversely related to temperature at continental scales. However, the net effect of climate on LCT-DOC is the product of cross-scale interactions between climate and vegetation. Plant traits also interact strongly with climate and have a measurable influence on LCT-DOC, with water use efficiency as the most influential plant trait because it couples terrestrial water and C cycling. We demonstrate that our conceptual framework and relatively simple linked C-hydrology process model of LCT-DOC can inform hypotheses and predict LCT-DOC.
156. 题目: Soil nutrient cycling and bacterial community structure in response to various green manures in a successive Eucalyptus ( E. urophylla × E . grandis ) plantation
期刊: Land Degradation & Development
作者: Zhuangzhuang Qian, Kongxin Zhu, Shunyao Zhuang, Luozhong Tang
摘要: Successive cultivation of short-rotation Eucalyptus plantations leads to serious decline in soil quality in China, which limits sustainable production. Green manure application is a potential strategy of improving soil fertility while ensuring ecological sustainability. Nevertheless, the impacts of various green manure species on soil quality in Eucalyptus plantations remain unclear. In the present study, we investigated how soil nutrient cycling and bacterial communities respond to various green manure species (Legume and Gramineae), namely Tephrosia candida, Sesbania cannabina, Lolium perenne, and Pennisetum purpureum (PP). A batch experiment was conducted using Eucalyptus plantation (E. urophylla × E. grandis) soil mixed with green manures for 60 d. According to the results, the PP treatment had the highest soil respiration rate among the five treatments, suggesting that PP application had the optimal effects on soil organic matter and residue decomposition. Furthermore, applying green manure increased bacterial diversity significantly when compared to CK (soil without green manure). Among the treatments, the PP treatment increased bacterial functional groups associated with the nitrogen cycle significantly, which result in rapid nutrient turnover. The rapid decomposition under PP may be responsible for the structural and functional changes in bacterial communities. Overall, the PP green manure is the optimal amendment for rapid nutrient supply in degraded Eucalyptus plantations over the short term. Our results could facilitate sustainable management of successive Eucalyptus plantations; nevertheless, extra investigations are needed to verify the long-term impacts of PP green manure in the field.
157. 题目: Removal of Cu, Pb and Zn from stormwater using an industrially manufactured sawdust and paddy husk derived biochar
期刊: Environmental Technology & Innovation
作者: Pamodithya Wijeyawardana, Nadeeshani Nanayakkara, Chamila Gunasekara, Anurudda Karunarathna, David Law, Biplob Kumar Pramanik
摘要: Direct flow of untreated stormwater containing Cu, Pb and Zn is of immediate concern to aquatic life in waterways. To date, most biochar used has been synthesized under controlled laboratory conditions using furnaces purged with inert gasses. In this study, the removal of Cu, Pb and Zn using biochar synthesized using paddy husk and sawdust feedstocks has used an industrial scale double chamber downdraft pyrolysis reactor. The effect of pyrolysis temperature and the effect of feedstock in the removal of Cu, Pb and Zn was evaluated by conducting batch adsorption experiments. Synthesized adsorbent materials were characterized using proximate analysis, zero-point charge, scanning electron microscopy, X-ray diffraction and Fourier Transform infrared spectroscopy. The biochar yield was in a lower range compared with the literature attributed to the higher heating rate (50 °C/min) in the pyrolizer. Maximum removal efficiencies were observed when the initial pH was at the value closest, when below the solubility limit for the heavy metals. The paddy husk biochar and sawdust biochar synthesized in the temperature range 350–450 °C and 450–550 °C performed best in the removal of the three heavy metals. Chemisorption was the main mechanism for the removal of the three heavy metals. The maximum adsorption capacities of Cu and Zn were 10.27 and 6.48 mg/g was achieved with paddy husk biochar and a maximum Pb adsorption capacity of 17.57 mg/g was achieved by sawdust biochar. Surface complexation, co-precipitation, p-electron interactions, physical adsorption and surface precipitation were the main mechanisms of removal of the three heavy metals.
158. 题目: Biomarkers and PAH chemostratigraphy in the study of the Frasnian anoxic event in the Pimenteiras Formation outcrop of the Parnaíba Basin, Brazil
期刊: Palaeogeography, Palaeoclimatology, Palaeoecology
作者: Iasmine Maciel Silva Souza, Eileen Rocio Niño Zambrano, Eliane Soares de Souza, Claudia Juliana Orejuela Parra, Hélio J.P. Severiano Ribeiro, José Roberto Cerqueira, Jefferson Mortatti, Olívia Maria Cordeiro de Oliveira, Antônio Fernando de Souza Queiroz
摘要: The Late Devonian is characterized by episodes of sea-level rise and expansion of dysoxic to anoxic paleoenvironments, resulting in a global abundance of organic-rich sedimentary rocks. These changes have been well documented in biostratigraphic studies of Euroamerica basins. However, the relationship between sea-level rise and marine anoxia in Western Gondwana sedimentary rocks is not completely understood. Here, biomarker and PAH diagnostic ratios were applied to investigate changing depositional paleoenvironment and organic matter inputs of the Pimenteiras Formation along the western edge of the Parnaíba Basin. First, 24 shale samples collected from 16 regionally distributed outcrops were analysed, revealing variability in depositional paleoenvironment conditions. Secondly, for detailed study a 15-m thick outcrop was chosen, from which 11 shale samples were collected. These samples were submitted to chemostratigraphic and palynostratigraphic analyses and their records were highlighted. Two sample groups were identified, one sample group containing mixed organic matter, predominantly terrigenous and with fresh-brackish water organisms, deposited under dysoxic conditions. The other sample group comprised mixed organic matter containing a high contribution of marine organisms, preserved under anoxic conditions. Results indicated a marine flooding surface in the Pimenteiras Formation Outcrop 1, associated with a Devonian transgressive event related to sea-level rise and probably to global anoxic conditions during the Frasnian in the Parnaíba Basin. In addition, it was possible to correlate the abundance of miospores Verrucosisporites genus with high Retene/Chrysene values, suggesting that these miospores can be associated with a biological precursor of retene.
159. 题目: Loss and Increase of the Electron Exchange Capacity of Natural Organic Matter during Its Reduction and Reoxidation: The Role of Quinone and Nonquinone Moieties
期刊: Environmental Science & Technology
作者: Peijie Yang, Tao Jiang, Zhiyuan Cong, Guangliang Liu, Yingying Guo, Yanwei Liu, Jianbo Shi, Ligang Hu, Yongguang Yin, Yong Cai, Guibin Jiang
摘要: Redox-active quinone and nonquinone moieties represent the electron exchange capacity (EEC) of natural organic matter (NOM), playing an important role in the electron transfer link of microbes and transformation of contaminants/metal minerals. However, the corresponding transformation of quinone/phenol and their respective influence on the EECs during reduction and reoxidation remain poorly characterized. Besides, it is still controversial whether nonquinones donate or accept electrons. Herein, we demonstrated that reoxidation of NOM after reduction can form new phenolic/quinone moieties, thus increasing the EEC. The assessment for the EEC, including the electron-donating capacity (EDC) and electron-accepting capacity (EAC), of nonquinones reflects the contribution of sulfur-containing moieties with considerable EDCs and EACs. In contrast, nitrogen-containing moieties donate negligible electrons even at Eh = +0.73 V. The contributions of both thiol and amine moieties to the EEC are greatly affected by adjacent functional groups. Meanwhile, aldehydes/ketones did not display an EAC during the electron transfer process of NOM. Furthermore, substantially increased EDC at Eh from +0.61 to +0.73 V could not be fully explained using thiol and phenolic moieties, suggesting the contribution of unknown moieties with high oxidation potential. The overall findings suggest that the roles of new quinones/phenol (derived from the addition of oxygen to condensed aromatic/lignin-like components) during redox dynamic cycling and thiol species should be considered in assessing the electron transfer processes of NOM.
160. 题目: Performance of biochars for the elimination of trace organic contaminants and metals from urban stormwater
期刊: Environmental Science: Water Research & Technology
作者: Stephanie Spahr, Marc Teixidó, Sarah S. Gall, James C. Pritchard, Nikolas Hagemann, Brigitte Helmreich, Richard G. Luthy
摘要: Urban stormwater carries dissolved organic and metal contaminants that pose risks to water supplies and the environment. Green infrastructure elements such as biofilters have the potential to capture and treat urban stormwater prior to infiltration to groundwater. Because conventional sand-based biofilters often fail to eliminate dissolved contaminants from stormwater, there is a need to improve biofilter treatment efficiency. In our study, we investigated four different wood-derived biochars for the removal of seven trace organic contaminants (TrOCs, atenolol, benzotriazole, dicamba, diuron, fipronil, mecoprop, terbutryn) and five metals (cadmium, copper, lead, nickel, zinc). Three biochars were produced at pyrolysis temperatures of 400 °C, 580 °C, and 750 °C, and one biochar of biomass gasification (1100–1400 °C). Batch experiments conducted with synthetic stormwater showed that the removal capacity of the biochars increased with increasing production temperature and specific surface area. The gasification biochar outperformed the three pyrolysis biochars and was further tested in flow-through column experiments operated for more than eight months and 4000 pore volumes. The least retained organic contaminant was dicamba followed by fipronil and terbutryn. Using a 1-D forward prediction intraparticle diffusion-limited sorption model, 20% breakthrough of dicamba was estimated to occur at 1100 and 5300 pore volumes in biochar-amended sand filters containing 1 to 10 weight percent biochar, respectively. Based on these results, case study calculations for a full-scale biochar filter in Los Angeles, CA, suggest potential service lifetimes of five years and longer when using dicamba as an indicator compound for early TrOC breakthrough.