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25841. 题目: Occurrence of organic compounds in groundwater of Saudi Arabia
文章编号: N19090207
期刊: Environmental Monitoring and Assessment
作者: Abdulaziz S. Alquwaizany, Sulaiman M. Alfadul, Mujahid A. Khan, Abdulrahman I. Alabdulaaly
更新时间: 2019-09-02
摘要: The presence of organic compounds in drinking water is well recognized in many developing countries; however, the occurrence of organic contaminants in the groundwater of Saudi Arabia, which is the main source of drinking water in the country, is not well documented. A national comprehensive study was carried out to assess the occurrence of organic compounds in groundwater wells used for drinking water purpose, in different regions of Saudi Arabia. A total of 993 well water samples were collected from all 13 administrative regions of the kingdom. Samples were analyzed for a total of 131 organic compounds using the standard methods. The results indicated that total organic carbon values were in the range of 0.01 to 84.13 mg/L with an average weighted value of 12.61 mg/L. Organic compounds were detected in only 9 regions, with 19.84% of the samples containing organic compounds. Only 96 wells (9.67%) showed contents of organic compounds above the safe limits. Pesticides were not detected in any of the well water samples. Overall, organic compounds were found in only 197 out of 993 wells (19.84%) in the whole country. Most of the wells containing organic compounds were located in residential, industrial, and agriculture areas. Riyadh region and Eastern Province were found to have the most affected wells as compared to other regions. Several regions did not show any organic compounds in the well waters. It can be said that the problem of groundwater contamination with organic compounds in Saudi Arabia is not acute and is manageable at present. It is, however, recommended that a regular monitoring of drinking water wells of all regions should be carried out by the competent authorities for organic compounds to know any contamination if and when it happens. Preventing such contaminants from reaching drinking water sources and protecting drinking water well heads from such contaminants remains a priority.
25842. 题目: New insight into the impact of biochar during vermi-stabilization of divergent biowastes: Literature synthesis and research pursuits
文章编号: N19090206
期刊: Chemosphere
作者: Muhammad Bilal Khan, Xiaoqiang Cui, Ghulam Jilani, Lin Tang, Min Lu, Xuerui Cao, Zulfiqar Ali Sahito, Yasir Hamid, Bilal Hussain, Xiaoe Yang, Zhenli He
更新时间: 2019-09-02
摘要: Biochar amendment for compost stabilization of divergent biowastes is gaining considerable attention due to environmental, agronomic and economic benefits. Research to date exhibits its favorable physico-chemical characteristics, viz. greater porosity, surface area, amount of functional groups, and cation exchange capacity (CEC), which allow interface with main nutrient cycles, favor microbial activities during composting, and improve the reproduction of earthworms during vermicomposting. Biochar amendment during composting and vermicomposting of biowastes boosts physico-chemical properties of compost mixture, microbial activities and organic matter degradation; and reduces nitrogen loss and emission of greenhouse gases (GHGs). It also improves the quality of final compost by increasing concentration of plant available nutrients, enhancing maturity, decreasing composting duration and reducing the toxicity of compost. Due to these characteristics, biochar could be considered a beneficial additive for the stabilization of different biowastes during composting and vermicomposting processes. Hence, good quality vermicompost, efficient recycling and management of biowastes could be achieved by addition of biochar through composting and vermicomposting.
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25843. 题目: PFOA and PFOS removal by ion exchange for water reuse and drinking applications: Role of organic matter characteristics
文章编号: N19090205
期刊: Environmental Science: Water Research & Technology
作者: Fuhar Dixit, Madjid Mohseni, Benoit Barbeau, Shadan Ghavam Mostafavi
更新时间: 2019-09-02
摘要: Perfluoroalkyl substances (PFAS) are drinking water contaminants of emerging concern due to their persistence in the environment and tendency to bio-accumulate. Although anionic ion exchange (IX) resins offer a cost-effective alternative for removing PFAS from natural waters, the studies on PFAS removal by IX under the influence of variable characteristics of the organic compounds present in the natural water sources, have been overlooked. This is critically important given that the organic matter (OM) characteristics are spatially variable and can change seasonally. In the present study, a strongly basic anion exchange resin was used to remove two of the most persistent PFAS, namely Per-fluorooctanoic acid (PFOA) and Per-fluorooctanesulfonic acid (PFOS). Factors influencing the uptake behavior included the PFOA and PFOS concentrations, resin dosage, and background OM characteristics, more specifically the charge density and molecular weight distribution of source water OM. The equivalent background concentration (EBC) was employed to evaluate the competitive uptake between OM and PFAS. Experimental data were fitted to different mathematical and physical models to evaluate the competitive interactions. Further, IX was able to achieve complete PFAS removal with simultaneous >60% Dissolved Organic Carbon (DOC) removal. Evidences of size exclusion and pore blockage were also observed in the presence of humics and larger molecular weight organic fractions. Results of this study indicate that IX exhibits great potential for simultaneous OM and PFAS removal for drinking and potable water reuse applications.
25844. 题目: Hydrothermal synthesizing sludge-based magnetite catalyst from ferric sludge and biosolids: Formation mechanism and catalytic performance
文章编号: N19090204
期刊: Science of The Total Environment
作者: He Zhang, Gang Xue, Hong Chen, Xiang Li
更新时间: 2019-09-02
摘要: Sludge-based magnetite catalyst (SBMC) containing Fe3O4 was synthesized by hydrothermal (HT) of biosolids and ferric sludge, which is a promising wasted sludge recycling way. The protein and carbohydrate, main representative compounds in biosolids, were used to explore the SBMC formation mechanism. A part of carbohydrate and the produced Maillard reaction products (MRPs) derived from two substrates via Maillard reaction (MR) were confirmed to participate in Fe3+ reduction. The MR accompanied by substrates humification, making MRPs own strong chelation activity. The MRPs (50–100 kDa) reflected the strongest relative reducing and chelation activity, mainly involving in Fe3O4 synthesis. Furthermore, the SBMC was verified as an efficient Fenton-like catalyst for aniline with 77.9% removal efficiency. The OH and O2– both contributed to the degradation, differing from only OH playing function in traditional Fenton-like system, implying biochar in SBMC could mediate the reactive oxygen species generating by Fe3O4, and benefit its catalytic performance.
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25845. 题目: Application of Simplicillium chinense for Cd and Pb biosorption and enhancing heavy metal phytoremediation of soils
文章编号: N19090203
期刊: Science of The Total Environment
作者: Zhongmin Jin, Songqiang Deng, Yuchen Wen, Yifeng Jin, Lin Pan, Yanfu Zhang, Tom Black, Kevin C. Jones, Hao Zhang, Dayi Zhang
更新时间: 2019-09-02
摘要: Phytoremediation is an effective approach to control soil heavy metal pollution. This study isolated a fungus strain from soils contaminated by cadmium (Cd) and lead (Pb) in Zhalong Wetland (China), which was identified as Simplicillium chinense QD10 via both genotypic and phenotypic analysis. The performance and mechanism of S. chinense QD10 in Cd and Pb adsorption was unraveled by morphological analysis and biosorption test, and its roles in ameliorating phytoremediation by Phragmites communis were tested in pot-experiments. Cd biosorption was attributed to the formation of Cd-chelate, whereas Pb was predominantly adsorbed by extracellular polymeric substances. Metal biosorption followed Langmuir isotherm, and the maximum biosorption capacity was 88.5 and 57.8 g/kg for Cd and Pb, respectively. Colonized in soils, such biosorption behavior of S. chinense QD10 can generate gradients of available Cr or Pb and drive their enrichment. Accordingly, S. chinense QD10 amendment significantly enhanced the phytoextraction of Cd and Pb by P. communis, possibly attributing to rhizospheric enrichment of Cd or Pb and defending effects on plants, explained by the significant removal of acid-extractable and reducible metals in soils and the increase of Cd and Pb content in P. communis tissues. The present study explored the mechanisms of S. chinense QD10 in Cd and Pb biosorption and proved its potential in ameliorating the phytoremediation performance at metal contaminated sites.
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25846. 题目: Biochar with near-neutral pH reduces ammonia volatilization and improves plant growth in a soil-plant system: A closed chamber experiment
文章编号: N19090202
期刊: Science of The Total Environment
作者: Sanchita Mandal, Erica Donner, Euan Smith, Binoy Sarkar, Enzo Lombi
更新时间: 2019-09-02
摘要: Ammonia (NH3) volatilization is considered as one of the major mechanisms responsible for the loss of nitrogen (N) from soil-plant systems worldwide. This study investigated the effect of biochar amendment to a calcareous soil (pH 7.8) on NH3 volatilization and plant N uptake. In particular, the effect of biochar's feedstock and application rate on both NH3 volatilization and plant growth were quantified using a specially designed closed chamber system. Two well-characterized biochars prepared from poultry manure (PM-BC) and green waste compost (GW-BC) were applied to the soil (0, 0.5, 1, 1.5 and 2% w/w equivalent to 0, 7.5, 15, 22 and 30 t ha−1) and wheat (Triticum aestivum, variety: Calingiri) was grown for 30 days. Both PM-BC and GW-BC decreased NH3 volatilization to a similar degree (by 47 and 38%, respectively), in the soil-plant system compared to the unamended control. Higher plant biomass production of up to 70% was obtained in the closed chamber systems with the addition of biochar. The increase in plant biomass was due to the reduction in N loss as NH3 gas, thereby increasing the N supply to the plants. Plant N uptake was improved by as much as 58% with biochar addition when additional NPK nutrients were supplied to the soil. This study demonstrates that the application of biochars can mitigate NH3 emission from calcareous agricultural cropping soil and that the retained N is plant-available and can improve wheat biomass yield.
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25847. 题目: Chloramination of iodide-containing waters: Formation of iodinated disinfection byproducts and toxicity correlation with total organic halides of treated waters
文章编号: N19090201
期刊: Science of The Total Environment
作者: Mahmut S. Ersan, Chao Liu, Gary Amy, Michael J. Plewa, Elizabeth D. Wagner, Tanju Karanfil
更新时间: 2019-09-02
摘要: The formation of iodinated disinfection byproducts (I-DBPs) in drinking waters is of a concern due to their higher cyto- and genotoxicity than their chlorinated and brominated analogues. This study investigated the formation of I-DBPs under chloramination conditions using preformed chloramine and associated cyto- and geno-toxicities obtained with Chinese Hamster Ovary (CHO) cell assay. Cyto- and geno-toxicity of the samples were also calculated using DBP toxicity index values and correlated with total organic halide (TOX) formation. In low iodide (I-) (0.32 μM, 40 μg L−1) water, increasing dissolved organic carbon (DOC) concentration of selected waters from 0.1 to 0.25 mg L−1 increased the formation of iodinated trihalomethanes (I-THMs), while further increases from 0.25 to 4 mg L−1 produced an opposite trend. In high iodide water (3.2 μM, 400 μg L−1), increasing DOC from 0.5 to 4 mg L−1 gradually increased the I-THM formation, while a decrease was observed at 5.4 mg L−1 DOC. Iodoform was the most influenced species from the changes in DOC concentration. While increasing the initial iodide concentration from 0 to 5 μM increased the formation of iodoform, it did not make any considerable impact on the formation of other I-THMs. The measured cytotoxicity of samples was significantly correlated with increasing DOC concentration. Unknown TOCl and TOI showed a high correlation with measured cytotoxicity, while calculated total organic chlorine (TOCl) and total organic iodine (TOI) did not correlate. The comparison of measured and calculated cytotoxicity values showed that the calculated values do not always represent the overall cytotoxicity, since the formation of unknown DBPs are not taken into consideration during the toxicity calculations.
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25848. 题目: Biowaste to treasure: Application of microbial-aged hydrochar in rice paddy could improve nitrogen use efficiency and rice grain free amino acids
文章编号: N19090113
期刊: Journal of Cleaner Production
作者: Shan Yu, Yanfang Feng, Lihong Xue, Haijun Sun, Lanfang Han, Linzhang Yang, Qingye Sun, Qingnan Chu
更新时间: 2019-09-01
摘要: Hydrochar is produced under hydrothermal carbonization, which can be considered as a cleaner process for black carbon production. Hydrochar shows good prospects in agro-environmental applications, but it is recommended to be ameliorated before application to improve its surface characteristics and reduce potential side-effects. This study, for the first time, proposed ameliorating poplar sawdust hydrochar via a microbial-aging process and applying it to rice paddy soil. In a soil-column experiment, sawdust hydrochar (SHC), microbial-aged SHC (M-SHC), and water-washed SHC (W-SHC) were added at different rates to examine their effects on rice growth and nitrogen usage efficiency (NUE). Additionally, the effects of hydrochar application on rice grain free amino acids (FAAs) were investigated. The study revealed that M-SHC had a positive effect on rice growth and increased the grain yield by 17.13%–22.99% compared with control. The NUE was also improved by M-SHC treatment. The positive effect of M-SHC on rice yield might be attributed to the reduced toxic biochar-derived dissolved organic matters, increased specific surface area, elevated hydrochar pH, and more nutrients released due to the microbial-aging process. Moreover, under M-SHC treatment, all 17 FAAs of grain were significantly higher than the control, by 46.26%. Both microbial-aging and water-washing amelioration of hydrochar had a positive effect on rice yield and FAAs, with the former exhibiting better prospects for application. This study will provide a new direction for cleaner recycling and utilization of biowaste.
25849. 题目: Antimony speciation and mobility during Fe(II)-induced transformation of humic acid-antimony(V)-iron(III) coprecipitates
文章编号: N19090112
期刊: Environmental Pollution
作者: Niloofar Karimian, Edward D. Burton, Scott G. Johnston
更新时间: 2019-09-01
摘要: Antimony, as the Sb(V) species, often occurs in oxic soils and sediments as coprecipitates with poorly-crystalline Fe(III)-bearing minerals. It is common for these Sb(V)-Fe(III) coprecipitates to also contain varying quantities of co-occurring humic acid (HA). When exposed to reducing conditions, the production of Fe(II) may cause the initial metastable HA-Sb(V)-Fe(III) phases to undergo rapid transformations to more stable phases, thereby potentially influencing the geochemical behavior of coprecipitated Sb(V). However, little is known about the impacts of this transformation on the mobility and speciation of Sb. In this study, we reacted synthetic HA-Sb(V)-Fe(III) coprecipitates (Fe:Sb ratio = 4, and C:Fe molar ratios = 0, 0.3, 0.8 and 1.3) with 0, 1 or 10 mM Fe(II) under O2-free conditions at pH 7.0 for 15 days. Fe K-edge EXAFS spectroscopy revealed that solid-phase Fe(III) in the initial coprecipitates contained a mixture of ∼4/5 ferrihydrite (Fe10O14(OH)2) and ∼1/5 tripuhyite (FeSbO4), regardless of the corresponding amount of coprecipitated HA. Tripuhyite persisted throughout the full experiment duration, while ferrihydrite was partially replaced by goethite (FeOOH) when either 1 or 10 mM Fe(II)aq was added to the coprecipitates. The greatest level of goethite formation (∼55% of solid-phase Fe) was observed in the HA-free/10 mM Fe(II)aq treatment, with ferrihydrite transformation being partially attenuated at higher levels of HA. Mobilisation of aqueous Sb was the greatest for 1 mM Fe(II) treatments at high HA:Fe ratios. Sb K-edge XANES spectroscopy showed that the largest reduction of Sb(V) to Sb(III) (∼37%) and the greatest repartitioning of Sb to the mineral surface (∼7.9–9.8%) occurred in the coprecipitates with the highest HA contents in the presence of 10 mM Fe(II). The results indicate that the amount of HA in HA-Sb(V)-Fe(III) coprecipitates can greatly influence mobility and speciation of Sb in Fe(II)-rich conditions. The results of this study provide new insights into alterations in Sb mobility and retention in response to Fe cycling under organic matter-rich reducing conditions.
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25850. 题目: Abiotic reduction of uranium(VI) with humic acid at mineral surfaces: Competing mechanisms, ligand and substituent effects, and electronic structure and vibrational properties
文章编号: N19090111
期刊: Environmental Pollution
作者: Qian Wang, Chang Zhu, Xiaoxiao Huang, Gang Yang
更新时间: 2019-09-01
摘要: Abiotic reduction represents an attractive technology to control U(VI) contamination. In this work, an abiotic route of U(VI) reduction with humic acid at mineral surfaces is proposed and reaction mechanisms are addressed by periodic density functional theory calculations. Different influencing factors such as ligand effect, content of CO32− ligands and substituent effect are inspected. The coordination chemistry of uranyl(VI) surface complexes relies strongly on substrates and ligands, and the calculated results are in good agreements with experimental observations available. For the OH− ligand, two competitive mechanisms co-exist that respectively produce the U(IV) and U(V) species, and the former is significantly preferred because of lower energy barriers. Instead, the NO3− ligand leads to the formation of U(V) while for the Cl− ligand, the U(VI) surface complex remains very stable and is not likely to be reduced because of very high energy barriers. The U(V) and U(IV) complexes are the predominant products for low and high CO32− contents, respectively. Accordingly, the abiotic reduction processes with humic acid are efficient to manage U(VI) contamination and become preferred under basic conditions or at higher CO32− contents. The U(VI) reduction is further promoted by introduction of electron-donating rather than electron-withdrawing substituents to humic acid. Electronic structure analyses and vibrational frequency assignments are calculated for the various uranium surface complexes of the reduction processes, serving as a guide for future experimental and engineered studies. The molecular-level understanding given in this work offers an abiotic route for efficient reduction of U(VI) and remediation of U(VI)-contaminated sites at ambient conditions.
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25851. 题目: Remediation of organic halogen- contaminated wetland soils using biochar
文章编号: N19090110
期刊: Science of The Total Environment
作者: Liqiang Cui, Chuntao Yin, Tianming Chen, Guixiang Quan, James A. Ippolito, Benzhi Liu, Jinlong Yan, Cheng Ding, Qaiser Hussain, Muhammad Umer
更新时间: 2019-09-01
摘要: Organochlorine waste from papermaking has polluted soils worldwide, and the addition of biochar will improve polluted soils in a variety of scenarios. A field study (2014 to 2016) was conducted to investigate the application of wheat (Triticum aestivum L.) straw biochar (0, 20, 40, 60 Mg ha−1) to organic halogen-contaminated saline-alkali soil. The addition of biochar reduced the concentrations of adsorbable organic halogens (AOX) in the soil and extractable organic halogens (EOX) in reeds (Phragmites communis) by 9–94% and 14%–51%, respectively, and subsequently increased reed biomass by 1%–25%; these changes were related to the changes in different soil properties. Soil properties, such as the organic functional groups, surface properties, and pH, were improved following the addition of biochar, and some changes were maintained at heightened levels over time. The activity of urease, alkaline phosphatase, and sucrase enzymes in soil increased by 14 to 57%, 2 to 147%, and 1 to 75% as a function of increasing biochar amendment, respectively, while that of dehydrogenase decreased by 13% to 60%, which may have aided in the acceleration of AOX decomposition. The diversity of the bacterial community also increased due to biochar application, and is likely a key indicator of halogen degradation. The addition of biochar likely decreased the bioavailability of organic halogens by improving the function and structure of the microbial community, reducing their transfer to reeds grown in papermaking organochlorine-contaminated soils. Biochar may play an important role in reducing environmental contamination by organic halogens.
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25852. 题目: Optical determination of black carbon mass concentrations in snow samples: A new analytical method
文章编号: N19090109
期刊: Science of The Total Environment
作者: Francisco Cereceda-Balic, Tamara Gorena, Camila Soto, Victor Vidal, Magín Lapuerta, Hans Moosmüller
更新时间: 2019-09-01
摘要: Black carbon (BC) aerosols in the atmosphere strongly affect direct radiative forcing and climate, not only while suspended in the atmosphere but also after deposition onto high albedo surfaces. Snow surfaces are especially sensitive to BC deposition, because of their high surface albedo and additional positive feedbacks further enhance faster snowpack melting caused by BC deposition, resulting in modifications in water resources and recession of glaciers. For the analysis of BC deposition on snow, a precise quantification of BC mass is needed. Instead, optical methods have the potential of quantifying only BC, based on its characteristic spectral absorption. Commercial optical transmissometers commonly use quartz filters to filter BC and measure its optical attenuation. They are calibrated for the determination of BC mass concentrations in air, but not adapted or calibrated for their determination in water or snowmelt samples. Additionally, they are generally calibrated using BC-simulating materials that are not representative of ambient BC particles.Here, a new analytical method is demonstrated for the quantitative determination of BC mass concentration in snow samples that considers filtering of melted snow with polycarbonate filters in a new device, and optical filter attenuation BC mass concentration measurement (880 nm). The attenuation can be obtained with any optical equipment that can measure the 880-nm attenuation of filters impacted with BC/snow impurities.This method has been calibrated using real diesel vehicle exhaust soot with well-known optical properties as reference material, yielding a multipoint calibration curve for common BC concentration levels in snow. The limits of detection (0.011 mg of BC), quantification (0.036 mg of BC) and reproducibility (96.39%) of this new analytical method have been determined. Real surface snow samples collected at different locations in “Los Andes” mountains of Chile were measured with this method given a BC concentrations ranged from 151 to 5987 μg kg−1.
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25853. 题目: Simulation of dissolved organic carbon concentrations and fluxes in Chinese monsoon forest ecosystems using a modified TRIPLEX-DOC model
文章编号: N19090108
期刊: Science of The Total Environment
作者: Shengwei Shi, Mingxia Yang, Yue Hou, Changhui Peng, Haibin Wu, Qiuan Zhu, Qiong Liang, Junfei Xie, Meng Wang
更新时间: 2019-09-01
摘要: Dissolved organic carbon (DOC) plays an important role in global and regional carbon cycles. However, the quantification of DOC in forest ecosystems remains uncertain. Here, the processed-based biogeochemical model TRIPLEX-DOC was modified by optimizing the function of soil organic carbon distribution with increasing depths, as well as DOC sorption-desorption efficiency. The model was validated by field measurements of DOC concentration and flux at five forest sites and Beijiang River basin in monsoon regions of China. Model validation indicated that seasonal patterns of DOC concentration across climatic zones were different, and these differences were captured by our model. Importantly, the modified model performed better than the original model. Indeed, model efficiency of the modified model increased from −0.78 to 0.19 for O horizon predictions, and from −0.46 to 0.42 for the mineral soils predictions. Likewise, DOC fluxes were better simulated by the modified model. At the site scale, the simulated DOC fluxes were strongly correlated with the observed values (R2 = 0.97, EF = 0.91). At the regional scale, the DOC flux predicted in the Beijiang River basin was 16.44 kg C/ha, which was close to the observed value of 17 kg C/ha. Using sensitivity analysis, we showed that temperature, precipitation and temperature sensitivity of DOC decomposition (Q10) were the most sensitive parameters when predicting DOC concentrations and fluxes in forest soils. We also found that both the percentage of DOC flux to forest net ecosystem productivity, and the retention of DOC by mineral soil were highly correlated with the amount of precipitation. Overall, our model validations indicated that the modified TRIPLEX-DOC model is a useful tool for simulating the dynamics of DOC concentrations and fluxes in forest ecosystems. We highlight that more accurate estimates of parameter Q10 in deep mineral soils can reduce model uncertainty, when simulating DOC concentrations and fluxes in forest soils.
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25854. 题目: Effect of metal-organic interactions on the oxidative potential of mixtures of atmospheric humic-like substances and copper/manganese as investigated by the dithiothreitol assay
文章编号: N19090107
期刊: Science of The Total Environment
作者: Manfei Lin, Jian Zhen Yu
更新时间: 2019-09-01
摘要: Excessive generation of reactive oxygen species (ROS) and the corresponding oxidative stress has been recognized as one important cause for the adverse health effects associated with exposure to ambient particulate matter (PM). Transition metals and humic-like substances (HULIS) in PM have been separately demonstrated to contribute to the oxidative potential (OP) of PM, however, only few studies investigated the impact of their interactions on the measured OP and the effect is little understood. HULIS is an abundant fraction of water-soluble organic material in PM and serves to represent real-world PM organics. In this study, we applied a cell-free dithiothreitol (DTT) assay to quantify the OP, termed as OPDTT, by two representative transition metals (i.e., copper (Cu) and manganese (Mn)), HULIS, and mixtures of HULIS and metals in concentration levels relevant to those in human lung fluid resulting from PM inhalation. The organic-metal mixture effect was found to be metal-specific and concentration-specific, covering the possibility spectrum from being synergistic, additive to antagonistic. HULIS was observed to suppress OPDTT up to 10–20% by Cu at a concentration of 0.08 μM while had no discernable effect at 0.5 μM Cu. On the contrary, obvious enhancement of OPDTT was recorded in the mixtures of HULIS and Mn (e.g. up to ~2 times at 2.5 μM of Mn) while no mixture effects could be discerned at 0.5 μM Mn. Our work demonstrates the need for considering the metal-organic interactions and the complexity when evaluating the total OP of their mixtures, such as ambient PM samples. Further work in metal-PM organics interactions should be conducted using methods capable of measuring specific oxidants, in addition to the ability to deplete the reducing agent (i.e., DTT), in order to acquire a deeper mechanistic insight into the interactions.
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25855. 题目: Resource utilization of a typical vegetable waste as biochars in removing phthalate acid esters from water: A sorption case study
文章编号: N19090106
期刊: Bioresource Technology
作者: Shi Yao, Xiaona Li, Hu Cheng, Chao Zhang, Yongrong Bian, Xin Jiang, Yang Song
更新时间: 2019-09-01
摘要: It is very important to utilize associated vegetable products as resources, especially in large-scale vegetable cultivation areas. In this study, pepper straw, a vegetable waste, was pyrolyzed into pepper straw biochars (PBs) to investigate their sorption potential for phthalate acid esters (PAEs). The results showed that PBs have porous structures and abundant surface functional groups. Dibutyl phthalate (DBP) and dimethyl phthalate (DMP) removal by PBs was divided into two stages, fast and slow sorption. The PBs pyrolyzed at 500 °C showed greater DBP and DMP sorption capacity than those pyrolyzed at 400 and 600 °C. Both chemical and physical sorption occurred in the whole sorption process of PAEs to PBs. It is proposed that converting pepper straw into biochars to use as sorbents could be an environmentally friendly way of vegetable waste resource utilization.
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25856. 题目: Impact of pine leaf biochar amendment on bacterial dynamics and correlation of environmental factors during pig manure composting
文章编号: N19090105
期刊: Bioresource Technology
作者: Jiao Li, Wenjing Xing, Huanyu Bao, Jinfeng Wang, Xiaogang Tong, He Zhang, Wanqing Luo, Fuyong Wu
更新时间: 2019-09-01
摘要: The influence of pine leaf biochar (PLB) amendment on bacterial community succession and its correlation with physic-chemical parameters during pig manure (PM) composting was evaluated. The five different dosages of PLB [at 0% (T1), 2.5% (T2), 5% (T3), 10% (T4) and 15% (T5)] mixed with initial composting mass were conducted to composting for 50 days. The present study indicated that bacterial diversity was significantly (p < 0.05) higher in PLB amended treatments than the control, but T4 treatment showed the highest among the all PLB applied treatment. Firmicutes, Actinobacteria, Proteobacteria and Bacteroidete were four most abundant phyla of all the treatments. Furthermore, redundancy analysis showed that the bacterial community were significantly (p < 0.05) positively correlated with temperature, pH, TOC, CO2 and NH3 emissions, while they were negatively correlated with the N2O and CH4 emission. Overall, the results suggested that the addition of 10% PLB (T4 treatment) was a potential option to enhance the composting efficiency with significantly greater abundance of bacterial community and finally improved the compost quality.
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25857. 题目: Characterization and influence of floc under different coagulation systems on ultrafiltration membrane fouling
文章编号: N19090104
期刊: Chemosphere
作者: Xue Shen, Baoyu Gao, Kangying Guo, Qinyan Yue
更新时间: 2019-09-01
摘要: A hybrid system was developed in this study consisting of different coagulation systems and ultrafiltration (UF). Property and effect of flocs formed in different coagulation systems on ultrafiltration membrane fouling control were investigated. All three coagulation systems, as pretreatment of UF, were effective in improving membrane flux and reducing membrane resistance within an appropriate range of natural organic matters (NOM) concentration. At high initial NOM concentration, the performance of polyaluminum chloride (PAC) on NOM removal and fouling control was severely limited. For PAC-poly dimethyl diallyl ammonium chloride (PAC-PolyDMDAAC) coagulation system, the limitation of initial NOM concentration on removing NOM and alleviating membrane fouling was slightly weakened, indicating composite flocculant PAC-PolyDMDAAC produced larger flocs through combined action of charge neutralization and adsorption bridging. In PAC + PolyDMDAAC dual coagulation system, the combined action of adsorption-bridging effect, sweeping effect, and charge neutralization were the mechanisms under both low and high initial NOM concentration. Although the flocs formed in PAC + PolyDMDAAC dual coagulation system had poor recovery ability compared with those formed in PAC and PAC-PolyDMDAAC coagulation system, flocs formed through adsorption-bridging and sweeping had large size and higher ability to resist shear force, resulting in the formation of cake layer with porous and fluffy structure and less blockage in membrane pore in PAC + PolyDMDAAC dual coagulation system. These results demonstrated that dual coagulation system combined PAC coagulation and PolyDMDAAC flocculation as a pretreatment of UF process can improve the characteristics of flocs and structure of cake layer for improving NOM removal and controlling membrane fouling.
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25858. 题目: Reconstructing organic matter sources and rain rates in the southern West Pacific Warm Pool during the transition from the deglaciation period to early Holocene
文章编号: N19090103
期刊: Chemical Geology
作者: Linying Chen, Min Luo, Andrew W. Dale, Harunur Rashid, Gang Lin, Duofu Chen
更新时间: 2019-09-01
摘要: Transient features in the organic carbon content of deep-sea sediment cores resulting from changes in the flux and/or quality of organic matter input are not uncommon. We examined the geochemical characteristics of sediments retrieved with a gravity core from the northwestern Solomon Sea (3908 m water depth), southern West Pacific Warm Pool (WPWP). δ13C and δ15N of sedimentary organic matter, together with TOC/TN data suggest that the organic material is characterized by a mixture of marine and terrestrial origins with a higher contribution from marine algae. The data were analyzed with an inverse non-steady-state reaction-transport model to examine the magnitude and variability of particulate organic carbon (POC) flux to the seafloor during the transition between the deglaciation period and early Holocene. Measured POC content and porewater NO3−, NH4+, DIC and SO42− concentrations were used to constrain the model. Hindcast results revealed that POC flux decreased from 75 to 37.5 μg cm−2 yr−1 during the deglaciation–early Holocene transition. The rate of POC degradation in the present setting is slightly lower compared to that in the pre-Holocene setting. The synchronous decline in the relative contribution of terrestrial organic matter input and rapid sea level rise during this transition suggest that sea level, rather than surface productivity, is the dominant factor controlling the POC deposition flux in the Solomon Sea. This is conceivable because the sampling site is proximal to high-relief islands with high rainfall, a well-developed submarine canyon system and narrow and steep continental margins. Consequently, we suggest that deep-water basins in proximity to similar high-relief mountainous islands in the tropical Pacific may represent important sinks for terrestrial organic material, especially during sea level lowstands.
25859. 题目: Removal of phosphate from aqueous solution using MgO-modified magnetic biochar derived from anaerobic digestion residue
文章编号: N19090102
期刊: Journal of Environmental Management
作者: Jiwei Liu, Jianguo Jiang, Aikelaimu Aihemaiti, Yuan Meng, Meng Yang, Yiwen Xu, Yuchen Gao, Quan Zou, Xuejing Chen
更新时间: 2019-09-01
摘要: A novel MgO-modified magnetic biochar (MgO@MBC) was made by chemical co-precipitation of Mg2+/Fe3+ on anaerobic digestion residue (ADR) and subsequently pyrolyzing at different temperatures. MgO@MBC was used for phosphate recovery from aqueous solution. The physicochemical properties of MgO@MBC were comprehensively investigated using TEM-EDS, FT-IR, XRD, VSM, N2 adsorption-desorption and TGA. Results showed that MgO/γ-Fe2O3 nanoparticles were successfully deposited onto the surface of BC. The effects of reaction temperature, initial solution pH, MgO@MBC dosage, coexisting anions and phosphate concentration on the removal of phosphate by MgO@MBC were researched. Additionally, the adsorption process of phosphate onto MgO@MBC was well described by the pseudo second-order and pseudo first-order models, which indicated a chemisorption and physisorption process. Besides, the maximum adsorption capacity of MgO@MBC for phosphate by the Langmuir model were 149.25 mg/g at 25 °C. Moreover, the thermodynamic study suggested that the adsorption of phosphate onto MgO@MBC was a spontaneous and endothermic process. The adsorption mechanisms including physical absorption, surface electrostatic attraction, surface complexation and precipitation were revealed. It could be concluded that MgO@MBC exhibited high removal efficiency of phosphate and excellent magnetic property for the recovery. MgO@MBC could be utilized as a magnetically recoverable adsorbent to realize phosphate recovery and MgO@MBC after the adsorpion of phosphate could be applied in agricultural production as a fertilizer.
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25860. 题目: Assessment of combustion and emission behavior of corn straw biochar briquette fuels under different temperatures
文章编号: N19090101
期刊: Journal of Environmental Management
作者: Ting Wang, Yuening Li, Dengke Zhi, Yingchao Lin, Kai He, Boyang Liu, Hongjun Mao
更新时间: 2019-09-01
摘要: The 350 °C and 700 °C corn straw biochars were used to produce solid fuel briquettes. NovoGro (NG), an industrial by-product, were selected as a binder in the briquetting process. The ratios of the raw material to NG was assumed as 100:1 and 50:1 (denoted as 350NB1, 350NB2, 700NB1 and 700NB2, respectively). The physicochemical and morphological properties, combustion characteristics and gas emissions of the four briquettes were investigated. The results revealed that the biochars and the NG binder performed a good combination. The low temperature biochar briquettes, especially 350NB2, had excellent combustion characteristics, including low H/C and O/C ratios (0.17 and 0.82), low gas emissions (104.06 mg/m3 of CO, 157.25 mg/m3 of NOx and 18.92 mg/m3 of SO2), optimal resistance to mechanical shock (~90%) and high calorific values (21.48 MJ/kg). Thus, NG is a good binder for the briquetting of biochar. The low temperature biochar was a good feedstock for solid fuel production in the improvement of the combustion and emission quality.
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