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22861. 题目: Pilot-scale coagulation of organic and inorganic impurities: Mechanisms, role of particle concentration and scale effects The intrusion of natural organic matter in the surface waters has impeded the dosing approaches in the realm of coagulation-flocculation. Scaling up bench-scale coagulant doses to pilot or full-scale systems generally results in decreased system efficiency. In this study, the pilot-scale reactors of Sludge blanket clarifier (SBC) and Conventional clariflocculator (CC), as well as jar test data, are compared for the treatment of synthetic waters (prepared by kaolin and humic acid) at high alkalinity by using poly aluminium chloride (PACl). The turbidity removal for CC and SBC was 43–84 % and 20–81 %; the TOC removal was 20–83 % and 11–84 %; the DOC removal was 27–87 % and 38–92 %; and the UV254 removal was 72–89 % and 75–91 % respectively. pH, alkalinity and zeta potential were analysed to understand the process mechanisms. Adsorption models of Langmuir, Freundlich, BET and Temkin isotherms were compared to further validate removal mechanisms. For SBC, the R2 and RMSE (Root mean square error) values suggested BET model at lower turbidity and Temkin model at higher turbidities, indicating physical adsorption at lower turbidity followed by significant humic acid-kaolin interactions at high turbidity. For CC, the dominant mechanism was physical and chemical adsorption which was monolayer at lower turbidity and multilayer at higher turbidity. The charge neutralization was dominant in CC, unlike SBC. The sludge collected in the pilot plants was analysed by FTIR for linking chemical interactions to the mechanisms of removal. The FTIR data revealed the presence of Al(OH)3 and aromatics suggesting dominant removal by adsorption and entrapment. | |||||
22862. 题目: Statistical Design of Experiments for Purification of Vanillin from Commercial Lignin using Ion Exchange | |||||
22863. 题目: Combined biochar and nitrogen application stimulates enzyme activity and root plasticity Biochar (BC) and nitrogen (N) fertilizers are frequently applied to improve soil properties and increase crop productivity. Nonetheless, our mechanistic understanding of plant-soil interactions under single or combined application of BC and N remains incomplete. For the first time, we applied a split-root system to evaluate how BC or N contributes to the changes in soil enzyme activities, N and phosphorus (P) cycling as well as root plasticity. Left and right parts of rhizoboxes were filled with silty-clay loamy soil amended with BC (15 g kg−1 soil, from wheat straw, 300 °C), N (0.05 g KNO3-N kg−1 soil) or a control (no amendments), resulting in the following combinations: BC/Control, N/Control, BC/N. Soil enzyme activities, available N and P, root morphology and plant biomass were analyzed after plant harvest. Plant biomass (shoot + root) ranged from 0.56 g pot−1 (BC/Control) to 0.91 g pot−1 (BC/N). The decreased soil bulk density and increased P availability in the BC compartment (BC/Control and BC/N) stimulated root length by 1.4–1.8 times – an effect that was independent of N availability in the same rhizobox. Biochar stimulated activities of β-glucosidase and leucine aminopeptidase (by 33–39%) compared to N due to the coupling of C, N and P cycles in BC/N treated soil. Nitrogen fertilization also increased β-glucosidase activity compared to the unfertilized control, whereas root elongation remained unaffected. Thus, the combined application of BC/N had more efficient benefits for plant growth than BC or N alone. This is linked with i) the stimulation of enzyme activities at the BC locations to reduce N limitation for both microorganisms and plants, and ii) an increase of fine root production to improve N uptake efficiency. Thus, combined BC/N application is potentially especially sustainable to overcome nutrient limitation as well as to maintain crop productivity because it accelerates root-microbial interactions. | |||||
22864. 题目: Changes in nutrient balance, environmental effects, and green development after returning farmland to forests: A case study in Ningxia, China Returning sloping farmland (>25°) to forest/grassland (RFTF) is an effective ecological measure for soil and water conservation. However, changes in nutrient cycles and green development are still unclear. Ningxia, in Northwestern China, began to implement RFTF in 2000. Here, we used the NUFER model to calculate the input and loss of nitrogen and phosphorus, utilization efficiency, production and consumption at food-chain scale in Ningxia for the period 1985–2015. Five aspects comprised the evaluation of green development: society, economy, resources, environment, and productivity. Results showed that forest coverage rate increased from 7.74% to 33.2%, while cropping area decreased by 6.6%. NH3 loss increased from 53,000 to 83,000 tons (56%), N2O increased from 1200 to 2300 tons (92%) and leaching loss from 18,000 to 62,000 tons (240%). Phosphorus leaching loss increased from 13,000 to 35,000 tons (130%). The environmental cost of food nitrogen per unit of production decreased from 8 to 6.7 kg/kg (19.4%). Nitrogen and phosphorus use efficiencies decreased by 4.8% and 58% in crops-animal systems, respectively, but increased by 652% and 430% in animal husbandry systems. The proportion of animal protein production increased from 18.3% to 39.0% (113%). The major source of organic waste was livestock and poultry manure and urine (70%). Indicators for achieving green development level increased from 14 to 18 (14.7%). Improving the level of scientific and technological management of aquaculture system, increasing the proportion of organic matter returned to farmlands, and paying attention to the combination of planting and breeding will effectively promote future cycling efficiency of nitrogen and phosphorus in the food chain, and the sustainability of agriculture towards green development. | |||||
22865. 题目: Leaching losses of dissolved organic carbon and nitrogen from agricultural soils in the upper US Midwest Leaching losses of dissolved organic carbon (DOC) and nitrogen (DON) from agricultural systems are important to water quality and carbon and nutrient balances but are rarely reported; the few available studies suggest linkages to litter production (DOC) and nitrogen fertilization (DON). In this study we examine the leaching of DOC, DON, NO3−, and NH4+ from no-till corn (maize) and perennial bioenergy crops (switchgrass, miscanthus, native grasses, restored prairie, and poplar) grown between 2009 and 2016 in a replicated field experiment in the upper Midwest U.S. Leaching was estimated from concentrations in soil water and modeled drainage (percolation) rates. DOC leaching rates (kg ha−1 yr−1) and volume-weighted mean concentrations (mg L−1) among cropping systems averaged 15.4 and 4.6, respectively; N fertilization had no effect and poplar lost the most DOC (21.8 and 6.9, respectively). DON leaching rates (kg ha−1 yr−1) and volume-weighted mean concentrations (mg L−1) under corn (the most heavily N-fertilized crop) averaged 4.5 and 1.0, respectively, which was higher than perennial grasses (mean: 1.5 and 0.5, respectively) and poplar (1.6 and 0.5, respectively). NO3− comprised the majority of total N leaching in all systems (59–92%). Average NO3− leaching (kg N ha−1 yr−1) under corn (35.3) was higher than perennial grasses (5.9) and poplar (7.2). NH4+ concentrations in soil water from all cropping systems were relatively low (<0.07 mg N L−1). Perennial crops leached more NO3− in the first few years after planting, and markedly less after. Among the fertilized crops, the leached N represented 14–38% of the added N over the study period; poplar lost the greatest proportion (38%) and corn was intermediate (23%). Requiring only one third or less of the N fertilization compared to corn, perennial bioenergy crops can substantially reduce N leaching and consequent movement into aquifers and surface waters. | |||||
22866. 题目: Phosphorus speciation during anaerobic digestion and subsequent solid/liquid separation This study aims to investigate the effect of anaerobic digestion (AD) on P species and how the different species are distributed in the digestate and digestate fractions, i.e. liquid and solid fractions. To do so, six full scale AD plants were used in this work and representative biomass samples were collected for investigation. P fractionation proceeded by adopting fractionation protocols consisting in step-by-step extraction with different solvents, (i.e. NaHCO3, HCl and NaOH-EDTA). Subsequently P species in the different fractions were identified by using 31P NMR. On average, AD did not substantially affect P speciation that depended on the P-fraction content of feeds. A high NaHCO3 fraction content in the ingestate determined, also, a high content of this fraction in the digestate, with consequently lower contents of both P-HCl and P-NaOH-EDTA, i.e. digestate P-fraction contents represented an inheritance of P speciation in the ingestate. A feed effect was observed in single plants. Highest pig/cow slurry content in the feeds seemed to decrease readily soluble P (extracted with NaHCO3) content and increased P associated with both organic matter and amorphous Fe/Al in the digestate. Again, using a large amount of digestate in the feed increased P-soluble content in the digestate. 31P NMR analyses revealed that inorganic P compounds dominated the spectra of all biomasses and fractions, with orthophosphate as the predominant species. When present, organic phosphorus compounds were typically represented by monophosphate esters, DNA and phospholipids, with a predominance of monophosphate esters. | |||||
22867. 题目: ROS-generation potential of Humic-like substances (HULIS) in ambient PM2.5 in urban Shanghai: Association with HULIS concentration and light absorbance Ambient fine particulate matter (PM2.5) can cause adverse health effects through the generation of reactive oxygen species (ROS) after inhalation. Humic-like substances (HULIS) are major constituents contributing to the ROS-generation potential in organic aerosols. In this study, PM2.5 samples in urban Shanghai during autumn and winter (2018–2019) were collected. Mass-normalized ·OH generation rate in surrogate lung fluid (SLF) was used to denote the intrinsic ROS-generation potential of PM2.5 or of the HULIS isolated from PM2.5. In this study, ROS-generation potential of PM2.5 decreased with increasing ambient PM2.5 concentration due to higher percentage of inorganic components in high PM2.5 event. Same trend was observed for the ROS-generation potential of unit mass of HULIS, which was higher when HULIS and PM2.5 concentrations were both relatively lower. The HULIS with high ROS-generation potential but low concentration (High-ROS/Low-Conc HULIS) were likely produced by the atmospheric aqueous-phase reactions during nighttime or under high relative humidity conditions, not from biomass burning emissions or the photochemical pollution products. The association between ROS-generation potential and light absorption properties of HULIS was studied as well. The High-ROS/Low-Conc HULIS also showed stronger light absorbance than the other HULIS. Our results implied the potentially important roles that HULIS species might play in atmospheric environment and human health even when the PM2.5 pollution is low. | |||||
22868. 题目: Adsorption of tetracycline hydrochloride onto ball-milled biochar: Governing factors and mechanisms Pristine and ball milled wheat stalk biochars pyrolysed at 300 °C, 450 °C, 600 °C were studied for tetracycline hydrochloride (TCH) adsorption from aqueous solution. Surface characteristics of ball milled biochar (BM-biochar) were significantly enhanced over their pristine counterparts. TCH adsorption occurred largely on external surface and by filling pores of biochars as evidenced by strong positive correlation between adsorption and external specific surface area (SSA), total pore volume, or mesoporous volume. A two-stage intra-particle diffusion model, limited by the TCH diffusion through the boundary liquid layer, well described TCH adsorption. Maximum TCH adsorption occurred at about pH = 6–8. While solution cations including Na+, K+ and Mg2+ subdued TCH adsorption as they competed for adsorption sites, Ca2+ promoted TCH adsorption due to formation of tetracycline-Ca2+ complexes. The best performing BM-biochar was the one pyrolysed at 600 °C with TCH adsorption amount of 84.54 mg/g. Therefore, this BM-biochar has the potential for TCH removal from aqueous solutions. And the research shed light on the management of organic contaminants in real wastewater by BM-biochar. | |||||
22869. 题目: Application of Orbitrap Mass Spectrometry to Investigate Seasonal Variations of Dissolved Organic Matter Composition in a Eutrophic Lake in Japan | |||||
22870. 题目: Tidal Marsh Restoration at Poplar Island: II. Elevation Trends, Vegetation Development, and Carbon Dynamics | |||||
22871. 题目: Pyrolysis of tomato harvest waste as a function of temperature and duration: Characteristics, production energy, and carbon dioxide emission in field conditions This study aimed to determine the physicochemical properties and production energy of biochars obtained from tomato harvest waste as a function of temperature and duration (holding time), and the influence of biochars on soil CO2 emission in the field condition. Pyrolysis was conducted in a 50 L-reactor with an electrical heating system. With a rise in pyrolysis temperature and holding time, pH, carbon, ash and fixed carbon contents, and energy consumption per unit mass of biochar increased, while volatiles content, and biochar yield decreased. The nitrogen content of biochars decreased with the increased holding time under the same temperature. Soil CO2 emission rose and declined with biochars produced at low and high temperatures, respectively, when mixed with the soil. The difference between the lowest (at 500 °C with the holding times of 240 min) and highest biochars-related soil CO2 emissions (at 300 °C with the holding times of 40 min) was 38.6 %. The pyrolysis temperature of 500 °C regardless of holding time appeared to reduce the energy consumption due to the biochar production, and soil respiration. | |||||
22872. 题目: Arsenic release in contaminated soil amended with unmodified and modified biochars derived from sawdust and rice husk | |||||
22873. 题目: Phosphate adsorption performance and mechanisms by nanoporous biochar–iron oxides from aqueous solutions | |||||
22874. 题目: Properties and adsorption mechanism of magnetic biochar modified with molybdenum disulfide for cadmium in aqueous solution In this paper, we present the preparation of MoS2-modified magnetic biochar (MoS2@MBC) as a novel adsorbent by a simple hydrothermal method. MoS2@MBC contains abundant S-containing functional groups that facilitate efficient Cd(II) removal from aqueous systems. We employed various characterization techniques to explore the morphology, surface area, and chemical composition of MoS2@MBC; these included Brunauer–Emmett–Teller analysis scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction,. The results indicated the successful decoration of the surface of MoS2@MBC with iron and MoS2, and a higher surface area of MoS2@MBC than that of unmodified biochar. Moreover, adsorption properties including thermodynamics and kinetics were investigated along with the effects of pH, humic acid, and ionic strength on the Cd(II) adsorption onto MoS2@MBC. The O-, C-, S-, and Fe-containing functional groups on the surface of MoS2@MBC led to an electrostatic attraction of Cd(II) and strong Cd–S complexation. The Langmuir and pseudo second-order models fitted best for the batch adsorption experiments results. The adsorption capacity of MoS2@MBC (139 mg g−1 on the basis of the Langmuir model) was 7.81 times higher than that of pristine biochar. The adsorption process was found to be pH-dependent. The experimental results indicated that MoS2@MBC is an effective adsorbent for removing Cd(II) from water solutions. Further, the adsorption process involved the complexation of Cd(II) with oxygen-based functional groups, ion exchange, electrostatic attraction, Cd(II)–π interactions, metal–sulfur complexation, and inner-surface complexation. This work provides new insights into the Cd(II) ions removal from water via adsorption. It also demonstrates that MoS2@MBC is an efficient and economic adsorbent to treat Cd(II)-contaminated water. | |||||
22875. 题目: Biochar derived from pyrolysis of oily sludge waste: Structural characteristics and electrochemical properties Oily sludge is the main hazardous waste produced by the petroleum industry, and its harmless disposal and recycling have become urgent problems. In this study, the pyrolysis technique was used to prepare oily sludge biochar at different temperatures (400 °C, 500 °C, 600 °C, and 700 °C). The characteristics of the biochar, including weight reduction, elemental composition, and molecular structure, were comprehensively investigated. From the perspective of the electrochemical properties of biochar, the relationship between the structure of the biochar and the redox capacity was discussed, and the feasibility of biochar as a battery cathode material was explored. The results suggested that the improper pyrolysis temperature could reduce the content of the quinone structure which was related to the redox capacity, the biochar prepared at 600 °C should have the strongest electron transfer capability. Moreover, the highest degree of condensation and aromaticity of pyrolysis products could be obtained at a higher pyrolysis temperature (700 °C), which might result in the relatively high discharge-charge capacity and good cycle performance of biochar which was used as an electrode material of a battery. This study explored the feasibility of pyrolysis as a disposal route for oily sludge waste and provided a reference for the electrochemical application of biochar prepared from oil sludge waste. | |||||
22876. 题目: A review of soil carbon dynamics resulting from agricultural practices Literature related to the carbon cycle and climate contains contradictory results with regard to whether agricultural practices increase or mitigate emission of greenhouse gases (GHGs). One opinion is that anthropogenic activities have distinct carbon footprints – measured as total emissions of GHGs resulting from an activity, in this case, agricultural operations. In contrast, it is argued that agriculture potentially serves to mitigate GHGs emissions when the best management practices are implemented. We review the literature on agricultural carbon footprints in the context of agricultural practices including soil, water and nutrient management. It has been reported that the management practices that enhance soil organic carbon (SOC) in arid and semi-arid areas include conversion of conventional tillage practices to conservation tillage approaches. We found that agricultural management in arid and semi-arid regions, which have specific characteristics related to high temperatures and low rainfall conditions, requires different practices for maintenance and restoration of SOC and for control of soil erosion compared to those used in Mediterranean, tropical regions. We recommend that in order to meet the global climate targets, quantification of net global warming potential of agricultural practices requires precise estimates of local, regional and global carbon budgets. We have conducted and present a case study for observing the development of deep soil carbon profile resulting from a 10-year wheat-cotton and wheat-maize rotation on semi-arid lands. Results showed that no tillage with mulch application had 14% (37.2 vs 43.3 Mg ha−1) higher SOC stocks in comparison to conventional tillage with mulch application. By implementing no tillage in conjunction with mulch application, lower carbon losses from soil can mitigate the risks associated with global warming. Therefore, it is necessary to reconsider agricultural practices and soil erosion after a land-use change when calculating global carbon footprints. | |||||
22877. 题目: Unexpectedly higher soil organic carbon accumulation in the evapotranspiration cover of a coal bottom ash mixed landfill Monolayer barriers, which are usually known as evapotranspiration (ET) covers, have long been used as alternative final cover systems in waste landfills. Coal bottom ash was evaluated as a good alternative to soil in landfill ET cover systems to increase the bottom ash (BA) recycling ratio in the past. In a previous study, applying BA promoted plant growth characteristics and improved the soil physicochemical properties, particularly the soil organic carbon (SOC) content. In this study, we investigated the effect of BA on the SOC increase by examining the chemical and physical characteristics of ET cover systems, and we compared BA mixed and pure soils. We collected two types of soil from the landfill cover, namely, BA mixed soil (BA 35% + soil 65%) and soil alone (100%), for treatments during the 5th year after installation. Bottom ash mixed soil has four times more SOC than the pure soil at the surface soil layer, but the SOC contents significantly decreased with the soil depth in BA mixed soil, and no differences were found between BA mixed soil and pure soil below a 25 cm soil depth. In addition, there was no significant difference in the chemical composition of the SOC according to a13C NMR. However, the allophane contents were significantly higher in BA mixed soil than pure soil, which physically protects the material from organic matter decomposition. Conclusively, the higher allophane content originating from BA might act as the primary factor in the high accumulation of soil organic carbon in the BA mixed soil layer by retarding the organic matter decomposition. | |||||
22878. 题目: Remediation of heavy metal contaminated soils by organic acid extraction and electrochemical adsorption Remediation of heavy metal contaminated soils remains a global challenge. Here, low-molecular-weight organic acids were used to extract Cu and Zn from polluted soils, and the extracted heavy metals were subsequently adsorbed by activated carbon electrodes. The electrochemical adsorption mechanism as well as the influence of pH, organic acid type and voltage were investigated, and the soil remediation effect was further evaluated by the cultivation of rape. After extraction by citrate at initial pH 8.3 and electrochemical adsorption at 0.9 V for 7 d, the concentrations of total and bioavailable Cu in soils decreased from 1090 to 281 to 391 and 52 mg kg−1, and those of Zn decreased from 262 to 39 to 208 and 30 mg kg−1, respectively. Cu and Zn ions were mainly electrochemically adsorbed on the carbon cathode and anode, respectively, resulting in decreases of their concentrations to below 1 mg L−1 in the leachate. The presence of organic acids improved the remediation performance in the order of citrate > oxalate > acetate. The decrease in the initial pH of citrate solution enhanced the removal rate of Zn, while seemed to have no effect on that of Cu. The removal capacity for heavy metals decreased with decreasing cell voltage from 0.9 to 0.3 V. In the rape cultivation experiment, the Cu and Zn contents in shoot and root were decreased by more than 50%, validating the soil remediation effect. The present work proposes a facile method for heavy metal removal from contaminated soils. | |||||
22879. 题目: Production of microalgal external organic matter in a Chlorella-dominated culture: influence of temperature and stress factors | |||||
22880. 题目: Controlled lacustrine microcosms show a brGDGT response to environmental perturbations Branched glycerol dialkyl glycerol tetraethers (brGDGTs) have proven useful for paleoclimate reconstructions. Nevertheless, the mechanism by which these biomarkers respond to the environment and the identity of the source organisms remain poorly understood. These gaps in knowledge have prevented the study of brGDGTs in culture, thereby limiting the use of these molecules as a tool for paleoclimate reconstruction. In this work we used controlled microcosms to study the effect of temperature and pH on brGDGTs in lake water. Our results show that temperature has a strong influence on the production of brGDGTs, with a sensitivity that is similar to empirical observations. In contrast, the pH experiments yielded inconclusive results either due to a limited response or to the experimental set up. This study demonstrates that the brGDGT response to temperature can be replicated under controlled conditions, establishing that microcosms are a viable strategy to better understand the proxy response mechanism. | |||||
