101. 题目: Explicit spatial modeling at the pore scale unravels the interplay of soil organic carbon storage and structure dynamics
期刊: Global Change Biology
作者: Simon Zech, Steffen A Schweizer, Franziska B Bucka, Nadja Ray, Ingrid Kögel‐Knabner, Alexander Prechtel
摘要: The structure of soil aggregates plays an important role for the turnover of particulate organic matter (POM) and vice versa. Analytical approaches usually do not disentangle the continuous re-organization of soil aggregates, caught between disintegration and assemblage. This led to a lack of understanding of the mechanistic relationship between aggregation and OM dynamics in soils.
102. 题目: Biochar-graphene oxide composite is efficient to adsorb and deliver copper and zinc in tropical soil
期刊: Journal of Cleaner Production
作者: Jefferson Santana da Silva Carneiro, Dagna Ariele da Costa Leite, Gustavo Mesquita de Castro, José Romão Franca, Lívia Botelho, Jenaina Ribeiro Soares, Juliano Elvis de Oliveira, Leônidas Carrijo Azevedo Melo
摘要: Highly weathered soils have low micronutrient availability and very low efficiency for most soluble fertilizers. In this article the effect of poultry litter biochar-graphene oxide composite (PLB-GO) as a novel adsorbent for copper (Cu) and zinc (Zn) was evaluated, as well as its fertilizing effects on plant growth, nutrient use efficiency and soil fertility. In order to do so, poultry litter biochar (PLB) and PLB-GO were produced, characterized and evaluated by isotherm adsorption and kinetics studies regarding their Cu and Zn sorption and desorption properties. Cu and Zn loaded on PLB and PLB-GO as biochar-based fertilizers (BBF) were also evaluated. PLB-GO showed 16.2% and 17.7% higher Cu and Zn adsorption capacity, respectively, than pristine PLB, and in both cases <0.5% of the sorbed metal content was released in water. Plant effects on growth and nutrient uptake were, in general, higher or similar to the results obtained for sulfates. The application of PLB increased Cu availability while PLB-GO increased Zn availability after cultivation, even after increasing nutrient uptake and being little soluble in water. Addition of small amounts (≤0.5%) of GO in biochar has potential to increase its properties to retain micronutrients and enhance the fertilizer use effectiveness in highly weathered soils.
103. 题目: Wheat straw biochar amendment significantly reduces nutrient leaching and increases green pepper yield in a less fertile soil
期刊: Environmental Technology & Innovation
作者: Joba Purkaystha, Shiv Prasher, Muhammad T Afzal, Christopher Nzediegwu, Jaskaran Dhiman
摘要: Declining soil fertility and inefficient water and nutrient use pose a growing challenge to increasing agricultural production to meet growing global food demand. As a soil amendment, biochar can potentially serve in addressing these issues; however, its impacts on nutrient leaching from soils of different pre-existing fertility levels are poorly understood. A potted green pepper (Capsicum annuum L. var. Red Night) production system, arranged in a randomized complete block design, imposed two soil fertility management approaches (‘fertile’: standard soil + [N:P:K (kg ha −1) 140:165:160] vs. ‘less fertile soil’: 1:1 standard soil : sand, [N:P:K (kg ha −1) 140:190:240], factorially combined with three levels of wheat straw biochar amendment [0%, 1%, and 3% (w/w)]. Biochar treatment effects on nutrient leaching (NO3−-N and PO43−-P) and plant yield were assessed for each soil fertility management approach. Across soil fertility types, biochar amendments (vs. the lack thereof) significantly decreased (p≤0.05) leachate volume (68%–91%) and cumulative NO3−-N (78%–93%) and PO43−-P (80%–99%) losses, whereas NO3−-N, and PO43−-P concentrations in the leachate were only significantly reduced (p≤ 0.05) under the 3% biochar amendment. Pepper marketable yield in the less fertile soil was significantly (40%, p≤0.05) greater under the 3% biochar amendment than the non-amended treatment; however, no such difference existed in the fertile soil given its initially high soil nutrient levels. While farmers can amend soils with biochar to reduce nutrient leaching, its impact on plant productivity will depend on the rate of amendment.
104. 题目: Effects of biochar on shear strength of completely decomposed granite
期刊: Environmental Science and Pollution Research
作者: Charles Wang Wai Ng, Weiling Cai, Pui San So, Jiaxin Liao, Sze Yu Lau
摘要: Biochar has a great potential to sustainably improve the performance of bio-engineered slope due to its ability to retain water and to supply nutrients. Existing studies mainly focus on hydrological properties of biochar-amended soil. However, the effects of biochar on shear strength of soil are not well studied. This study aims to assess the shearing behaviour of biochar-amended completely decomposed granite (CDG). Soil specimens were prepared by mixing CDG with two types of biochar at a mass ratio of 5% and compacted at 95% of the maximum dry density. Although the peak shear strength of biochar-amended CDG is reduced by up to 20% because of lower initial dry density of the soil and crushing of biochar particles during shearing, both types of biochar have negligible effects on the ultimate shear strength, which is governed by friction between soil particles. This highlights that the ultimate friction angle can be adopted for designing bio-engineered slopes using biochar-amended soils.
105. 题目: Drinking water aromaticity and treatability predicted from dissolved organic matter fluorescence
期刊: Water Research
作者: Marc PHILIBERT, Simin LUO, Lavel MOUSSANAS, Qingqing YUAN, Emmanuelle FILLOUX, Flavia ZRAICK, Kathleen R MURPHY
摘要: Samples from fifty-five surface water resources and twenty-five drinking water treatment plants in Europe, Africa, Asia, and USA were used to analyse the fluorescence composition of global surface waters and predict aromaticity and treatability from fluorescence excitation emission matrices. Nine underlying fluorescence components were identified in the dataset using parallel factor analysis (PARAFAC) and differences in aromaticity and treatability could be predicted from ratios between components Hii (λex/λem= 385/520), Hiii (λex/λem= 325/404), Pi, (λex/λem=275/300) and Pii (λex/λem= 290/362). Component Hii tracked humic acids of primarily plant origin, Hiii tracked weathered/oxidised humics and the “building block” fraction measured by LC-OCD, while Pi and Pii tracked amino acids in the “low molecular weight neutrals” LC-OCD fraction. Ratios between PARAFAC components predicted DOC removal at lab scale for French rivers in standardized tests involving coagulation, powdered activated carbon (PAC), chlorination, ion exchange (IEX), and ozonation, alone and in combination. The ratio Hii/Hiii, for convenience named “PARIX” standing for “PARAFAC index”, predicted SUVA according to a simple relationship: SUVA = 4.0 x PARIX (RMSEp=0.55) LmgC−1m−1. These results expand the utility of fluorescence spectroscopy in water treatment applications, by demonstrating the existence of previously unknown relationships between fluorescence composition, aromaticity and treatability that appear to hold across diverse surface waters at various stages of drinking water treatment.
106. 题目: Fluoride-Contaminated Water Remediation Using Biochar derived from Dairy Processing Sludge
期刊: Chemical Engineering Journal
作者: Shakya Abeysinghe, Kitae Baek
摘要: Seeking a technically reliable disposal platform for milk sludge has drawn particular concern considering its hazardous potential to our environment. Milk sludge from the dissolved air flotation process has abundant calcium because of the naturally available calcium in milk and lime addition as a coagulant. No previous study on its ability to remove fluoride based on its abundant calcium has been reported. As a strategic measure to minimize the environmental impacts, milk sludge was pyrolyzed. Milk sludge biochar was used as an adsorbent to remove fluoride from water. To delineate the close relationships between the fluoride removal capacity and the physico-chemical properties of biochar, milk sludge biochar was fabricated at the temperature range from 500 to 800 ˚C. In an effort to align the experimental/theoretical data, adsorption kinetics, isotherms, column studies, and equilibrium modelling using visual MINTEQ 3.1 were conducted. In addition, milk sludge biochar was characterized using field-emission scanning electron microscopy, X-ray diffraction, and Fourier transform infrared spectroscopy. Biochar fabricated at 800 °C (MS800) exhibited the highest fluoride removal capacity of 485.9 mg/g. Only MS800 mainly composed highly soluble Ca(OH)2 while the other temperature-prepared biochar mainly composed of less soluble CaCO3. Consequently, MS800 is providing more Ca2+ to the system. At the equilibrium, MS800 releases Ca2+ ∼200 mg/g into water within 24 hours. X-ray diffraction of the spent biochar shows that fluoride was removed by forming a CaF2 precipitation. All experimental findings of this study confirmed that milk sludge converted into a value-added, efficient environmental media to remediate fluoride-contaminated wastewater.
107. 题目: Organic matter degradation and redistribution of sediment associated contaminants by benthic invertebrate activities
期刊: Environmental Pollution
作者: Tom V van der Meer, Piet F.M. Verdonschot, Lina Dokter, Samira Absalah, Michiel H.S. Kraak
摘要: The fate of sediment associated compounds is the combined result of chemical properties and biological activities. Yet, studies simultaneously addressing the effects of biota on the redistribution and bioaccumulation of contaminants are scarce. Our aim was therefore to assess the effect of benthic invertebrate activities on organic matter degradation and the redistribution of metals and Polycyclic Aromatic Hydrocarbons (PAHs) in contaminated sediment. To this end, we introduced egg ropes of the non-biting midge Chironomus riparius into wastewater treatment plant sludge and allowed these to either develop until fourth instar larvae or to fully complete their life cycle into terrestrial flying adults. Chironomid larvae enhanced sludge degradation, resulting in increased metal concentrations in the sludge and in a flux of metals into the overlying water. Moreover, they hampered PAH degradation in the sludge. Contaminant transport from aquatic to terrestrial ecosystems with emerging invertebrates as a vector is widely acknowledged, but here we showed that biomanipulation prevailed over bioaccumulation, since due to chironomid activity, the flux of metals from the sludge into the overlying water was larger than into chironomid biomass. It is therefore concluded that contaminant-macroinvertebrate interactions are bilateral relationships driven by the interplay between macroinvertebrate traits and contaminant properties.
108. 题目: Efficient removal of aqueous Cr(VI) with ferrous sulfide/N-doped biochar composites: Facile, in-situ preparation and Cr(VI) uptake performance and mechanism
期刊: Science of The Total Environment
作者: Dong Chen, Xiaohu Du, Kunyuan Chen, Guangrong Liu, Xin Jin, Chuanfu Song, Feidei He, Qiang Huang
摘要: FeS nanoparticles loaded on nitrogen-doped biochar (FeS/BNC) were fabricated by pyrolyzing coffee husks pretreated with Mohr's salt. The nitrogen doping and FeS loading of biochar are simultaneously achieved in one-pot pyrolysis. The elemental analysis, SEM, TEM, XRD, XPS, Raman, FTIR and N2 adsorption-desorption technologies were used to characterize the composition and structure of FeS/NBC. The appraisement for removing aqueous Cr(VI) testified that FeS/NBC offered a synergistic scavenging effect of Cr(VI) by FeS and NBC. The effect of crucial experimental conditions (FeS/NBC dosage, foreign ions, initial pH and concentration of Cr(VI) solution) were investigated. The Cr(VI) removal capacity was as high as 211.3 ± 26 mg g−1 under the optimized condition. The practicability of FeS/NBC was examined by using simulated actual samples from tap water and lake water. The mechanism examination showed that surface adsorption/reduction and solution reduction were implicated in the removal of Cr(VI). The current work introduces a novel FeS/NBC composite prepared by an in situ pyrolysis method with excellent potential for chromium pollution remediation.
109. 题目: Peroxymonosulfate activation by cobalt particles embedded into biochar for levofloxacin degradation: Efficiency, stability, and mechanism
期刊: Separation and Purification Technology
作者: Jiayun Liu, Jing Jiang, Min Wang, Jin Kang, Jian Zhang, Shuan Liu, Yiwu Tang, Siyan Li
摘要: Embedding metal particles into carbonaceous materials has promising prospects in antibiotic removal because of its good peroxymonosulfate (PMS) activation efficiency and low metal leaching risk. However, previous studies focused on metal particles embedding nanotubes, which is limited by high cost and complex preparation processes. Hence, in this study, low-cost and easily obtained biochar (BC) was chosen to prepare Co nanoparticles (Co NPs) embedded into carbonaceous materials through a one-step facile pyrolysis method. The optimized Co@RBC800 exhibited excellent PMS activation efficiency toward levofloxacin (LVF) degradation. Compared to the structure of conventional Co particles loaded on the surface of BC (Co-BC), this special structure of Co NPs embedded into BC exhibited more stability in cycle experiments and negligible Co ion leaching. Based on the quenching experiment, electron paramagnetic resonance (EPR), in situ Raman testing, electrochemical analysis, and density functional theory (DFT) calculations, it was found that the 1O2 and electron transfer mechanisms played a dominant role in LVF degradation in the Co@RBC800/PMS system. In addition, Co@RBC800 displayed excellent anti-interference ability, easy recovery performance and universal applicability. This work supplies a new means for the rational modification of BC materials for high-efficiency PMS activation performance with little metal ion leaching risk in antibiotic removal, which is proven by an in-depth exploration of the reaction mechanism.
110. 题目: Effects of biochar particle size and dosage on the desiccation cracking behavior of a silty clay
期刊: Science of The Total Environment
作者: Yu Lu, Kai Gu, Zhengtao Shen, Xiang Wang, Yuping Zhang, Chao-Sheng Tang, Bin Shi
摘要: Desiccation cracking can significantly change the integrity of soils, and potentially result in the instability of infrastructure as well as the migration of contaminants. Biochar is regarded as a promising low-carbon material for geotechnical applications, including cracking prevention. This study investigates the effects of biochar particle size and dosage on the desiccation cracking characteristics of a silty clay. For samples with fine biochar particles (<0.25 mm), coarser primary cracks initiate first, followed by finer secondary cracks regardless of biochar dosage. Quantitative analysis of the cracking characteristics at the stable stage shows that the surface crack ratio, the number of crack segments, the total length of cracks and the average width of cracks decreased by 31.29%, 30.78%, 14.18%, and 20.45% after 10% biochar addition. For samples with coarse biochar particles (>0.25 mm), cracks initiate simultaneously on the soil surface, and primary and secondary cracks are difficult to distinguish after drying, especially in high dosage samples. In the presence of 10% biochar, the surface crack ratio and average width of cracks decreased by 28.64% and 62.84%, but the number of crack segments and total length of cracks increased by 163.39% and 42.13%. Microstructure and image processing analysis of soil cracks indicate that biochar affects the crack initiation and propagation process by altering the soil microstructure and thereby the crack parameters. The contact between biochar and soil particles transitions from close contact to loose contact as the size of the biochar particles increases. In general, the application of 10% biochar with fine particle size had the best performance in inhibiting soil cracking.
111. 题目: Fe–N complex biochar as a superior partner of sodium sulfide for methyl orange decolorization by combination of adsorption and reduction
期刊: Journal of Environmental Management
作者: Zhijun Ren, Zhanxin Wang, Longyi Lv, Peiyu Ma, Guangming Zhang, Yuyou Li, Yu Qin, Pengfei Wang, Xiaoyang Liu, Wenfang Gao
摘要: To enhance the decolorization of methyl orange (MO), Fe–N complex biochar (Fe-N-BC) was developed as an accelerator in the sodium sulfide (Na2S) reduction system. The decolorization effect and mechanism of MO in the Fe-N-BC/Na2S composite system were studied. Surface pore analysis, Raman spectroscopy, FT-IR, XPS, and electrochemical analysis were used to characterize Fe-N-BC and unmodified biochar (BC). These results demonstrated that Fe-N-BC had better adsorption performance (specific surface area 463.46 m2 g−1) and electron transfer capacity than BC. By adding Fe-N-BC to the Na2S reduction system for MO, it was found that the decolorization of MO was greatly improved (increased by 93%). Besides, the effects of critical factors such as the initial concentration of Na2S, the dosage of Fe-N-BC, pH value, and temperature on the decolorization rate of MO were evaluated. Through the analysis of the action mechanism, the cooperation mode of Fe-N-BC and Na2S was to form an infinite cycle of adsorption-reduction-regeneration, so as to realize the rapid decolorization of MO. On the one hand, Fe-N-BC could adsorb MO and Na2S on its surface to increase the contact opportunity; on the other hand, it could act as a redox mediator to accelerate the electron transfer of the reduction reaction. In addition, the degradation of MO by Na2S was also an in-situ regeneration of Fe-N-BC. These findings may provide a feasible method to decolorize azo dyes quickly by cooperating with chemical reducing agents from a new perspective.
112. 题目: Molecular and spectroscopic changes of peat-derived organic matter following photo-exposure: Effects on heteroatom composition of DOM
期刊: Science of The Total Environment
作者: Mourad Harir, Kaelin M. Cawley, Norbert Hertkorn, Philippe Schmitt-Kopplin, Rudolf Jaffé
摘要: The temporal evolution of molecular compositions and changes in structural features of Hillsboro Canal (Florida, USA) dissolved organic matter (DOM) was studied with an emphasis on nitrogen and sulfur containing molecules, after a 13 day time-series exposure to simulated sunlight. The Hillsboro Canal drains from the ridge and slough wetland environment underlain by peat soils from the northern extent of the Greater Everglades Ecosystem. The Hillsboro Canal-DOM was characterized by combining ultrahigh-resolution mass spectrometry (FT-ICR-MS), high-field nuclear magnetic resonance spectroscopy (1H NMR), size exclusion chromatography (SEC) with UV detection, and ultraviolet/visible (UV/vis) absorbance and excitation emission matrix (EEM) fluorescence spectroscopy. Size exclusion chromatography (SEC) demonstrated progressive depletion of higher mass molecules and a concomitant decrease of absorbance during photo-irradiation. NMR and FT-ICR-MS revealed nonlinear temporal evolution of DOM. In fact, FT-ICR-MS showed an initial depletion of supposedly chromophoric molecules often carrying major unsaturation accompanied by an uneven evolution of numbers of CHO, CHOS and CHNO compounds. While CHNO compounds continually increased throughout the entire photo-exposure time, CHO and CHOS compounds temporarily increased but declined after further light exposure. Progressive loss of highly unsaturated compounds was accompanied by production of low mass CHO and CHNO compounds with high O/C ratios. Area-normalized 1H NMR spectra of DOM in water and of the water insoluble fraction (~5%) in methanol revealed clear distinctions between irradiated and non-irradiated samples and congruent evolution of DOM structural features during irradiation, with more uniform trends in methanolic-DOM. Photoirradiation caused initial photoproduction of oxygenated aliphatic compounds, continued depletion of phenols and oxygenated aromatics, substantial change from initial natural product derived olefins to photoproduced olefins, and uneven evolution of carboxylated and alkylated benzene derivatives. This study demonstrates longer-term heteroatom-dependent photochemistry of DOM, which will affect the speciation of N and S heteroatoms, their connections to inorganic nutrients, and potentially their bioavailability.
113. 题目: Development of a novel biochar/iron oxide composite from green algae for bisphenol-A removal: Adsorption and Fenton-like reaction
期刊: Environmental Technology & Innovation
作者: Chen Yu, Jingchun Tang, Hongji Su, Jingci Huang, Fangheng Liu, Lan Wang, Hongwen Sun
摘要: In this study, algae of Aegagropila linnaei (AL) was selected as low-cost raw material to synthesize biochar/iron oxide composites for the removal of bisphenol-A (BPA). Pristine biochar (BC) with olive-shaped pores and KOH-activated acid washed biochar (ABC) with novel interconnected structure were successfully prepared and further functionalized with ferrous sulfate for effective soldering of Fe3O4 nanoparticles onto the surface of acid biochar through hydrothermal method. The iron modified acid biochar composite (FABC) was found to be with the optimal physicochemical property such as smaller crystalline size (100-150 nm), larger surface area (144.62 m2/g), larger pore volume (0.259 cm 3/g), lower capacitance decrease (2.3%), and lower resistance (0.73 Ω) as compared to other modified biochar. The removal rates of BPA by BC, ABC, and FABC were 43.2 ± 0.5%, 52.6 ± 0.3%, and 69.8 ± 2.3%, respectively, when the concentration of BPA was 10 mg/L (pH 3.0, 303k). Under acidic conditions (at pH 3.0), the reaction activity and the adsorption of hydrogen ions onto Fe3O4 nanoparticles in FABC was prompted, and further increasing the removal rate of BPA. The result suggests that adsorption played main role, while active species (⋅OH and ⋅O2−) produced by the nano-iron oxide on the surface of the composites played some effect in the removal of BPA.
114. 题目: Exploring origin of oxygen-consuming organic matter in a newly developed quasi-hypoxic coastal ocean, the Bohai Sea (China): A stable carbon isotope perspective
期刊: Science of The Total Environment
作者: Zhuo-yun Chen, Wei-dong Zhai, Shu Yang, Yong Zhang, Peng-fei Liu
摘要: The Bohai Sea, adjacent to the Northwest Pacific, is a semi-enclosed shallow-water marginal sea that was considered on a critical path of eutrophication and environmental degradation. To better understand the Bohai Sea metabolism-induced summertime dissolved oxygen (DO) decline, five field surveys were conducted between July 2019 and July 2021 to investigate the seasonal/interannual and spatial variations in DO, dissolved inorganic carbon (DIC), and stable isotopic composition of DIC (δ13CDIC). Although the water-mixing scheme was subject to spatial variation, a uniform apparent ratio of δ13CDIC versus apparent oxygen utilization was estimated at −0.0122‰ per μmol O2 kg−1 in the Bohai Sea in summer. Based on a three-endmember water-mixing model and the mass balance of DIC and its stable isotopic composition, the assumed uniform δ13C values of oxygen-consuming organic matter in the Bohai Sea DO-deficient areas was estimated to be −19.47 ± 1.85‰ in 2020 and between −20.6‰ and − 18.1‰ in 2021. This isotopic composition is very similar to the δ13C value of organic matter from marine diatoms, but different to that of terrestrial organic matter sources surrounding the Bohai Sea. Our results indicate that nearly all the organic matter consumed by community respiration in the Bohai Sea is produced in situ by marine plankton. To mitigate the seasonal DO shortage in the Bohai Sea, reduction of allochthonous nutrients is crucial.
115. 题目: Multiple environmental risk assessments of heavy metals and optimization of sludge dewatering: Red mud–reed straw biochar combined with Fe2+ activated H2O2
期刊: Journal of Environmental Management
作者: He Li, Jiaao Chen, Jiaxing Zhang, Tenglong Dai, Han Yi, Fangyuan Chen, Min Zhou, Haobo Hou
摘要: In this study, Fe-rich biochar (RMRS-BC) was prepared from red mud and reed straw to improve sludge dewatering and transformation of heavy metals (HMs, including Cd, Cr, Cu, Pb, and Zn). The optimal concentrations of RMRS-BC, Fe2+, and H2O2 to promote sludge dewaterability were identified by response surface methodology (RSM). The optimal dosages of RMRS-BC, Fe2+, and H2O2 were 74.0, 104.9, and 75.7 mg/g dry solids (DS), respectively. The corresponding capillary suction time (CST) and water content of sludge cake were 14.3 s and 51.25 wt%. For the improvement mechanism, heterogeneous and homogeneous Fenton reactions occurred due to RMRS-BC and Fe2+ activating H2O2. The extracellular polymeric substances (EPS) decomposed into dissolved organic matter (proteins and polysaccharides), thereby promoting the transformation of bound water to free water and further reducing the water content of the sludge cake. The research quantitatively assessed the environmental risk of heavy metals in the conditioned sludge cake based on bioavailability and ecotoxicity, pollution levels and potential ecological risks. Compound conditioning using RMRS-BC, Fe2+, and H2O2 could significantly improve the solubility and reduce the leaching toxicity of HMs. In general, RMRS-BC combined with Fe2+ to activate H2O2 provided an effective method to enhance sludge dewaterability and reduce HMs risk.
116. 题目: Ferric chloride aiding nitrite pretreatment for the enhancement of the quantity and quality of short-chain fatty acids production in waste activated sludge
期刊: Water Research
作者: Yue Lu, Xunkuo Zhang, Xuran Liu, Qi Lu, Zijing Li, Jun Xiao, Yifu Li, Xingxin Hu, Qingqing Xie, Dongbo Wang
摘要: The production of short-chain fatty acids (SCFAs) via anaerobic fermentation of waste activated sludge (WAS) is often limited with poor quality of SCFAs and long fermentation time. To overcome the issues, we provided an efficient strategy by using ferric chloride (FC) to aid nitrite pretreatment. Experimental results showed that the maximal SCFAs production of 211.3 ± 3.1 mg COD/g VS was achieved with 4 mmol/L of FC integrated with 250 mg/L of nitrite pretreatment on day 5, which was 4.1-fold higher than that of the blank control (52 ± 5 mg COD/g VS, day 7). Besides, the enrichment of acetic acid was observed in the combined system, which accounted for 54.6 ± 3.5% of total SCFAs, while only 31.5 ± 4.9% was detected in the blank control. Propionic acid, iso-butyric acid, n-butyric acid, n-valeric acid and iso-valeric acid accounted for 14.7 ± 1.5%, 6.9 ± 1.4%, 7.4 ± 1.5%, 13.1 ± 1.0%, and 3.3 ± 1.5% of total SCFAs in the combined system and 22.8 ± 4.0%, 11.9 ± 3.0%, 6.7 ± 3.1%, 17.6 ± 2.0%, and 9.5 ± 3.9% of total SCFAs in the blank control, respectively. It was found that soluble proteins and carbohydrates in the combined system were higher than those in the blank control, suggesting that FC and nitrite pretreatment benefited WAS disintegration. The fluorescence spectrum results suggested that FC and nitrite pretreatment improved the biodegradability of the released organics, which provided more biodegradable substances for the subsequent SCFAs production. This was because the addition of FC induced the formation of free nitrous acid from nitrite. Besides, FC-induced iron reduction also promoted the conversion of recalcitrant organics to biodegradable organic matter. Microbial community structure analysis demonstrated that the functional bacteria involved in acetogenesis process such as Enterococcus, Proteiniclasticum, and Petrimonas were highly enriched due to the pretreatment of FC and nitrite, indicating this method could improve the relative abundance of SCFAs producers. Overall, this study revealed that the pretreatment of FC and nitrite promoted the formation of free nitrous acid and increased the yield of SCFAs, which provided a novel method for wastewater treatment plants to ameliorate the sewage treatment craft and rationally use the existing substances in WAS to enhance resource recovery.
117. 题目: A green strategy from waste red mud to Fe0-based biochar for sulfadiazine treatment by peroxydisulfate activation
期刊: Chemical Engineering Journal
作者: Dongmei Ma, Jing Wang, Kun Feng, Bingfeng Liu, Guojun Xie, Defeng Xing
摘要: Zerovalent iron (Fe0)-based biochar (Fe0-BC) has attracted wide attention in activating persulfate to eliminate antibiotics. In this study, the waste red mud (RM) was successfully used as an iron precursor to prepare Fe0-BC (RMIS1:1) via co-pyrolysis strategy, which was confirmed with remarkable capacity in peroxydisulfate (PDS) activation. The removal efficiency of sulfadiazine (SDZ) was 99.7% in RMIS1:1/PDS system in 20 min, with kobs of 0.3001 min-1. Both free radicals (SO4•-, •OH, and O2•-) and non-free radicals (1O2) were responsible for SDZ degradation, in which the SO4•- and O2•- played the dominant roles. Four SDZ degradation pathways were provided according to the intermediates identified by Q-TOF-MS. Furthermore, the ECOSAR prediction implied that the intermediates have less eco-toxicity than SDZ. Compared with PDS concentration and RMIS1:1 dosage, the initial SDZ concentration had stronger effect on its degradation. Co-existed Cl- slightly improved SDZ degradation rate, while other anions (NO3-/SO42-/HCO3-/CO32-) and humic acid exhibited different levels of inhibition on SDZ removal. Moreover, RMIS1:1/PDS maintained acceptable degradation ability for practical pharmaceutical wastewater. The electrical energy per mass of SDZ was about 2.24 kWh/(g·SDZ) by RMIS1:1/PDS, lower than that produced in any other advanced oxidation processes that have been reported so far. In summary, this study reported a green strategy for Fe0-BC preparation from RM, which was valuable for both waste resource recycling and environmental remediation.
118. 题目: Physical Protection in Aggregates and Organo-Mineral Associations Contribute to Carbon Stabilization at the Transition Zone of Seasonally Saturated Wetlands
作者: Anna I. Kottkamp, C. Nathan Jones, Margaret A. Palmer, Katherine L. Tully
摘要: Wetlands store significant soil organic carbon (SOC) globally due to anoxic conditions that suppress SOC loss. However, stored SOC may become vulnerable to decomposition where climate and land use change alter wetland hydrology. Seasonally saturated wetlands experience fluctuating hydrologic conditions that could promote physicochemical mechanisms known to stabilize terrestrial SOC. These wetlands are therefore likely to be important for SOC storage at the landscape-scale. This study examined physicochemical stabilization of SOC within five seasonally saturated wetlands across a hydrologic gradient from the frequently saturated basin edge to the rarely saturated upland. At each wetland, we monitored water level and collected soil samples from the top two mineral horizons across five transect points to quantify physical protection of SOC in aggregates and organo-mineral associations between SOC and iron (Fe). As expected, both SOC concentrations and SOC stocks from 10–50 cm decreased across the transect from frequently saturated soils to rarely saturated soils. However, SOC stocks from 0–10 cm increased along this gradient, indicating diverging SOC dynamics throughout the soil profile. The majority of SOC was associated with macroaggregates across the transect, suggesting that macroaggregates are likely to physically protect wetland SOC during seasonal drying. By contrast, Fe-associated SOC was low across the transect, though modest accumulations of Fe (5 mg Fe g−1 soil) were observed in the transition zone where saturation was most dynamic throughout the year. Our results suggest that SOC stabilization occurs via physical protection within macroaggregates and, to a lesser extent, organo-mineral associations during dry periods in and around seasonally saturated wetlands. As climate scenarios predict intensified wet and dry cycles in many wetlands, understanding SOC stabilization is critical to predicting vulnerability to future change.
119. 题目: Performance and mechanisms of biochar for promoting the removal efficiency of organic solids in the vermi-wetland during the recycling of excess sludge
期刊: Journal of Cleaner Production
作者: Gratien Twagirayezu, Kui Huang, Chunlei Sang, Mengxin Guan, Hui Xia, Yiwen Li, Junjie Xu
摘要: Although the vermi-wetland associated with earthworms and plants can recycle the excess sludge, the efficiency of organic solids decomposition needs to be improved. This study. aimed at investigating the effects and mechanisms of biochar added to a vermi-wetland by promoting the removal efficiency of organic solids during excess sludge treatment. Two vermi-wetland systems were built, with the wetland plant Acorus calamus and the earthworm Eisenia fetida inoculated. The corncob biochar was blended into the top and bottom layers of one of the vermi-reactors. The results revealed that the removal rates of chemical oxygen demand and total solids separately accounted for 86.2%–94.3% and 64.93%–82.40% of the vermi-wetland with biochar. They were significantly (P < 0.01) higher by 8.1% and 15.7% than those of the vermi-wetland without biochar, respectively. Compared to the counterpart, the interception loading of organic matter significantly decreased (P < 0.05) by 1.6 times in the vermi-wetland with biochar. In addition, an intense and broad carbonyl group substance was adsorbed in the vertical profile of the vermi-wetland with biochar. Biochar enhanced members of Luteimonas, Sphingomonas, and Paracoccus that enable the decomposition of organic solids in the vermi-wetland. This study suggests that the addition of biochar in the vermi-wetland can promote the treatment performance of excess sludge via enhancing the organic interception and bacterial community diversity.
120. 题目: Biochar production with amelioration of Microwave-assisted pyrolysis: Current scenario, drawbacks and perspectives
期刊: Bioresource Technology
作者: Vishal Hadiya, Kartik Popat, Shaili Vyas, Sunita Varjani, Meththika Vithanage, Vijai Kumar Gupta, Avelino Núñez Delgado, Yaoyu Zhou, Pau Loke Show, Muhammad Bilal, Zhien Zhang, Mika Sillanpää, Swayansu Sabyasachi Mohanty, Zeel Patel
摘要: In recent years, biomass has been reported to obtain a wide range of value-added products. Biochar can be obtained by heating a variety of biomass, which aids in carbon sinks, soil amendments, resource recovery, and water retention. Microwave technology stands out among various biomass heating technologies not only for its effectiveness in biomass pyrolysis for the production of biochar and biofuel but also for its speed, volumetrics, selectivity, and efficiency. The features of microwave-assisted biomass pyrolysis and biochar are briefly reviewed in this paper. An informative comparison has been drawn between microwave-assisted pyrolysis and conventional pyrolysis. It focuses mainly on technological and economic scenario of biochar production and environmental impacts of using biochar. This source of knowledge would aid in the exploration of new possibilities and scope for employing microwave-assisted pyrolysis technology to produce biochar.