21. 题目: Nitrogen removal, sludge activity and bacterial community in a sequencing batch reactor at different ciprofloxacin and ibuprofen concentrations
期刊: Environmental Technology & Innovation
作者: Shengyu Yuan, Zichao Wang, Yueyue Wang, Huan Yang, Youtao Song, Naishun Bu, Lin Wang, Lu Zhang
摘要: Nitrogen removal, sludge activity and bacterial community were examined at different ciprofloxacin and ibuprofen concentrations in a sequencing batch reactor. Ammonia nitrogen (NH4+-N) and chemical oxygen demand (COD) elimination rates decreased as the ciprofloxacin (belonged to antibiotics) and/or ibuprofen (belonged to nonsteroidal anti-inflammatory drugs) addition. Ciprofloxacin and ibuprofen had antagonistic inhibitions on the specific rates of nitrate reduction, nitrite oxidation and ammonium oxidation. The levels of protein and polysaccharide and the protein/polysaccharide ratio in extracellular polymeric substances rose as the increment of ibuprofen, ciprofloxacin and mixed ibuprofen/ciprofloxacin concentrations. Mixed ibuprofen/ciprofloxacin did not change the role of protein in extracellular polymeric substances in the bacterial defense to ibuprofen or ciprofloxacin, and tryptophan-like protein was the main protective response of bacteria to ibuprofen, ciprofloxacin and mixed ibuprofen/ciprofloxacin compared with aromatic protein. Both of nitrifiers and denitrifiers relative abundances were lower at the mixed ibuprofen/ciprofloxacin than at the alone ibuprofen stress, while were higher than at the single ciprofloxacin pressure.
22. 题目: Investigation of aliphatic hydrocarbons in core sediments of Brunei Bay, East Malaysia
期刊: Marine Pollution Bulletin
作者: Swee Yun Pang, Suhaimi Suratman, Joo Hui Tay, Norhayati Mohd Tahir
摘要: The distribution of aliphatic hydrocarbons in three sediment cores from Brunei Bay was investigated in order to understand their sources and the biogeochemical processes of these hydrocarbons. The total concentrations of C15 to C37 n-alkanes ranged from 0.70 to 16.5 μg g−1. Traces of hopanes with C29–C31 carbon homologs were detected in the study area. The carbon preference index (CPI15–37) ranged from 1.23 to 3.42 coupled with the natural n-alkane ratio (NAR19–32) ratios (1.52 to 5.34), and the presence of unresolved complex mixtures and hopanes, suggested slight contamination by anthropogenic hydrocarbons, presumably derived from activities along the coasts. The presence of C27 trisnorhopene and diploptene, as well as their association with long-chain and short-chain n-alkanes, revealed a depositional environment of organic matter in the sediment cores.
23. 题目: Fabrication and environmental applications of metal-containing solid waste/biochar composites: A review
期刊: Science of The Total Environment
作者: Ruohan Zhao, Bing Wang, Benny K.G. Theng, Pan Wu, Fang Liu, Xinqing Lee, Miao Chen, Jing Sun
摘要: The resource utilization of industrial solid waste has become a hot issue worldwide. Composites of biochar with metal-rich industrial solid wastes (MCSWs) can not only improve the adsorption performance, but also reduce the cost of modification and promote the recycling of waste resources. Thus, the synthesis and applications of biochar composites modified by MCSWs have been attracting increasing attention. However, different MCSWs may result in metal-containing solid waste/biochar composites (MCSW-BCs) with various physicochemical properties and adsorption performance, causing distinct adsorption mechanisms and applications. Although a lot of researches have been carried out, it is still in infancy. In particular, the explanation on the adsorption mechanisms and influencing factors of pollutant onto MCSW-BCs are not comprehensive and clear enough. Therefore, a systematic review on fabrication and potential environmental applications of different MCSW-BCs is highly needed. Here we summarize the recent advances on the utilization of typical metal-containing solid wastes, preparation of MCSW-BCs, adsorption mechanisms and influencing factors of pollutants by MCSW-BCs as well as their environmental applications. Finally, comments and perspectives for future studies are proposed.
24. 题目: Influential mechanism of water occurrence states of waste-activated sludge: specifically focusing on the roles of EPS micro-spatial distribution and cation-dominated interfacial properties
期刊: Water Research
作者: Boran Wu, Hao Wang, Xiaohu Dai, Xiaoli Chai
摘要: The highly hydrated colloidal structure of waste-activated sludge (WAS) is the main obstacle of enhanced dewatering for sludge volume minimization. Extracellular polymeric substances (EPS) maintain the colloidal stability of bio-flocs in a three-dimensional matrix due to bindings with bivalent cations (i.e., Ca2+ and Mg2+) and hydrophobic interactions. However, few studies specifically focused on the quantitative relationships among spatial distribution of EPS, microstructure of bio-flocs and fractions of bound water (e.g. vicinal water and interstitial water). Thus, there may be still some debates on whether and what extent of the lysis or flocculation of sludge flocs is optimal for the dewaterability improvement. This study applied the gradient addition of cation exchange resin (CER) to remove EPS-complexed cations and loosen the spatial distribution of EPS. Consequently, how the spatial extension of EPS layers with relief of complex cations influenced the particle size distribution, fractal dimension, interfacial free energy and water occurrence states of WAS was systematically investigated. The quartz crystal microbalance with dissipation (QCM-D) was also applied to analyze the water-EPS interactions with and without the presence of Ca2+ and Mg2+. All the results confirmed that the dispersed EPS adhering layers led to the higher fractal dimension (Df) but the lower space filling degree of bio-flocs. Also, the 4-fold reduction in the polar/acid-based interfacial free energy could be induced by the removal of cations from EPS matrix, which indicated the significant increase in hydrophobicity. Predictably, the fractions of vicinal water and interstitial water were dominated by the polar/acid-based interfacial free energy and pore structure of microbial aggregates, respectively, which were confirmed by the strong Pearson correlation (Rp>0.80, p-value<0.04). These findings are expected to provide the improved mechanistic insights into the relationship between water occurrence states and colloidal structure of WAS, and can serve as the basis for the optimal combination of various sludge conditioning approaches towards regulating aggregation states of bio-flocs.
25. 题目: Soil organic carbon (SOC) enrichment in aeolian sediments and SOC loss by dust emission in the desert steppe, China
期刊: Science of The Total Environment
作者: Heqiang Du, Sen Li, Nicholas P. Webb, Xiaoan Zuo, Xuyang Liu
摘要: Dust emission is an important mechanism for carbon exchange between terrestrial and atmospheric carbon pools. However, undetermined soil organic carbon (SOC) enrichment in aeolian sediment limits the accurate estimation of SOC loss induced by wind erosion. Herein, we examined wind erosion and SOC loss measurements in the desert steppe of Inner Mongolia, China. By testing the particle size distributions (PSDs) and SOC contents across different particle size groups of the soil samples and aeolian sediments, we found that the finer soil particles generally had higher SOC contents. According to the measured results, we recognized that the mechanism of SOC enrichment in aeolian sediment is the inconstant distribution of SOC across the different soil particle size groups and the differences between the PSDs of soils and aeolian sediments. Based on the mechanism, we proposed a method to calculate the SOC content in aeolian sediment, and the calculated results are highly consistent with the measured results. Compared with the previous method, our calculation method provided a more precise result. Integrating our method for estimating SOC content in dust (diameter less than 50 μm) and a dust emission model, we simulated the SOC loss induced by wind erosion in this region by a wind erosion model, and the results show SOC loss induced by dust emissions ranging from 0 to 39 g/m2/y during the period of 2001 to 2017. We believe the study method of dust SOC content calculation we proposed could be interested by the scholars in the field of carbon cycling, and the simulated results of SOC loss could provide robust data for the estimation of carbon budget in the desert steppe.
26. 题目: Surface-constructing of visible-light Bi2WO6/CeO2 nanophotocatalyst grafted PVDF membrane for degradation of tetracycline and humic acid
期刊: Journal of Hazardous Materials
作者: S.A. Gokula Krishnan, S. Abinaya, G. Arthanareeswaran, Saravanan Govindaraju, Kyusik Yun
摘要: The synthesis of Bi2WO6 and CeO2 photocatalytic nanomaterials exhibit a great ability to photodegrade the antibiotics and and shown excellent oxidation of various organic pollutants. Heterostructure 1:1 & 2:1 Bi2WO6/CeO2 nanocomposite was successfully synthesized via the facile sono-dispersion method and exquisite photocatalytic activity. The 0.5wt% of nanocomposites were well-grafted on PVDF membrane surface via an in-situ polymerization method using polyacrylic acid. The fourier transform infrared (FTIR) spectra demonstrated that the network formation in PVDF induced by the -COOH functional group in acrylic acid. The grafted membrane morphology and strong binding ability over the membranes were validated by scanning electron microscope with energy dispersion (SEM-EDS) and X-ray photoelectron spectroscopy (XPS), respectively. The permeate flux of 49.2L. m-2 h-1 and 41.65L. m-2 h were observed for tetracycline and the humic acid solution respectively for 1wt% of PVP and 0.5wt% of photocatalytic nanomaterials in PVDF membrane. The tetracycline and humic acid photodegradation rate of 82% and 78% and total resistance of 3.04×1011 m-1 and 1.75×1011 m-1, 80.5% and 76% flux recovery ratio were observed with N5 membrane. The 2:1 Bi2WO6/CeO2 nanocomposite grafted membrane showed a high permeate flux and better photodegradation ability of organic pollutants in the wastewater.
27. 题目: Organic mulching alters the composition, but not the diversity, of rhizosphere bacterial and fungal communities
期刊: Applied Soil Ecology
作者: Xiaodan Sun, Yuqian Ye, Jiahui Liao, Yifan Tang, Dong Wang, Qingwei Guan
摘要: Organic mulching is an effective forest management technique that provides carbon and nutrient sources to soil ecosystems, thereby improving the soil environment and promoting plant growth. Although the importance of rhizosphere microbiomes in plant and soil ecosystem functions has been widely recognised, the effect of organic mulching on rhizosphere microorganisms and the underlying mechanisms are unclear. We performed a field experiment in a 15-year-old Ligustrum lucidum forest of urban green space. The diversity and composition of the rhizosphere bacterial and fungal communities following organic mulching were assessed by combining 16S ribosomal RNA and internal transcribed spacer amplicon sequencing. The correlations between microbial diversity, composition, and fine-root traits, as well as rhizosphere soil properties, were also analysed. The results showed that organic mulching did not significantly affect the diversity of the rhizosphere bacterial or fungal communities on the whole, but it increased the bacterial diversity after 6 months, with a 20-cm-thick mulch layer showing a greater effect than 5- or 10-cm layers. Organic mulching significantly altered the rhizosphere bacterial and fungal community composition; after 6 months of mulching, the community compositions were significantly associated with fine-root traits (specific root length, nitrogen, and phosphorus concentration) and enzyme (urease and dehydrogenase) activity. Moreover, alterations in the bacterial and fungal communities occurred at the order level within each mulching stage. Bacterial diversity is affected by fungal diversity and rhizosphere soil properties (water content and organic carbon) in time-dependent manners. Hence, organic mulching appears to directly affect the fungal composition while indirectly affecting the bacterial composition via influencing rhizosphere soil properties (dissolved organic carbon and peroxidase activity). Our study suggests that organic mulching affects the rhizosphere bacterial and fungal community composition through different pathways; however, the underlying mechanisms, including the effects of time and soil layers, require further exploration combined with multi-index measurements and long-term dynamic monitoring.
28. 题目: Factors governing microalgae harvesting efficiency by flocculation using cationic polymers
期刊: Bioresource Technology
作者: Hang P. Vu, Luong N. Nguyen, Benjamin Emmerton, Qilin Wang, Peter J. Ralph, Long D. Nghiem
摘要: This study aims to elucidate the mechanisms governing the harvesting efficiency of Chlorella vulgaris by flocculation using a cationic polymer. Flocculation efficiency increased as microalgae culture matured (i.e. 35−45, 75, and >97% efficiency at early, late exponential, and stationary phase, respectively. Unlike the negative impact of phosphate on flocculation in traditional wastewater treatment; here, phosphorous residue did not influence the flocculation efficiency of C. vulgaris. The observed dependency of flocculation efficiency on growth phase was driven by changes in microalgal cell properties. Microalgal extracellular polymeric substances (EPS) in both bound and free forms at stationary phase were two and three times higher than those at late exponential and early phase, respectively. Microalgae cells also became more negatively charged as they matured. Negatively charged and high EPS content together with the addition of high molecular weight and positively charged polymer could facilitate effective flocculation via charge neutralisation and bridging.
29. 题目: Gypsum and pressmud amelioration improve soil organic carbon storage and stability in sodic agroecosystems
期刊: Land Degradation & Development
作者: Nirmalendu Basak, Parvender Sheoran, Raman Sharma, Rajender Kumar Yadav, Ranjay K. Singh, Satyendra Kumar, K. Thimmappa, Parbodh C. Sharma
摘要: Salinity–induced land degradation poses threat to environment and food production globally. Farmers’ participatory research (2014–18) was carried out to assess the potential of gypsum (Gyp) and pressmud (PM) in alleviating the sodicity stress, and improvement in soil organic carbon (SOC) pools and its stability in Trans Indo–Gangetic Plains of India. Intensive rice–wheat cultivation using alkali water increased soil pH, exchangeable sodium percentage (ESP) and bulk density (BD) causing a net depletion in SOC. Gypsum (supplies soluble Ca2+) and pressmud (mobilizes native CaCO3) mediated amelioration (Gyp+PM) significantly decreased soil sodification and compaction, and improved total organic carbon (TOC; 32–64%) over the unamended control. Higher left–over C for SOC stabilization, crop biomass and rhizodeposition returned through Gyp+PM significantly improved SOC pools and C sequestration culminating in ~25% yield superiority over the unamended control. Within SOC pools, highest proportion was equally retained in very labile and non–labile C pools. On average, the passive pool contained ~45% of TOC; albeit to a greater contribution through PM followed by Gyp+PM and Gyp. Rice–wheat system yield (RWSY) was positively correlated with SOC pools and indices while negatively correlated with soil pH, ESP, BD, CaCO3 and recalcitrant index. Multiple regression analysis showed stratification ratio, CaCO3, sensitivity index and BD as key variables for yield prediction under the existing levels of soil sodicity. The key insights suggest ecosystem based approach using Gyp+PM in restoring the degraded lands, enhancing crop resilience and system (SOC enrichment and storage) stability, and achieving UN–Sustainable Development Goals related to food security and Land Degradation Neutrality.
30. 题目: Self-Organized Colloids Thermodynamically Weaken the Effect of Salt on Methane Hydrate Formation
期刊: ACS Sustainable Chemistry & Engineering
作者: Yanzhen Liu, Yu Feng, Yang Zhao, Lei Yang, Hongsheng Dong, Lunxiang Zhang, Jiafei Zhao
摘要: Natural gas hydrate deposits are typically rich in organic matter; they together with the host sediments play a crucial role in the nucleation and accumulation of gas hydrates, yet their potential thermodynamic effect on hydrate formation is rarely studied. In the present work, it was found that the deprotonated organic compounds could self-organize with the cations in the solution, forming organic colloids via coordination bonds. Elemental mapping showed that these organic colloids were filled with Ca2+ and Na+ ions as well as more concentrated organic matter surrounded by thin rings of Mg2+ and Cl– ions. This was found to result in a concentration decrease of Ca2+ and Na+ ions in the solution with the presence of the colloids; the resulting decreased electrostatic effect of salt ions on water molecules would subsequently relieve the energy barrier of hydrate formation, showing a shift of the phase equilibrium conditions to a milder situation. This finding would be more nontrivial in low-permeability hydrate layers where mass exchange with the abundant ions in the seawater could be rather sluggish. The results could be of help in determining the local thickness and location of the gas hydrate stability zone and thereby the estimated reserves.
31. 题目: Bioelectrochemical process for simultaneous removal of copper, ammonium and organic matter using an algae-assisted triple-chamber microbial fuel cell
期刊: Science of The Total Environment
作者: Zhigang Yang, Jiaze Li, Feiyong Chen, Linxu Xu, Yan Jin, Sisi Xu, Jin Wang, Xue Shen, Lijie Zhang, Yang Song
摘要: Considering the adverse effect of heavy metals (such as Cu2+) on biological wastewater treatment processes, an algae-assisted triple-chamber microbial fuel cell (MFC) was established to remove Cu2+, COD and nitrogen sequentially, and also generate electricity. About 86.2% of the Cu2+ was removed in the first cathodic chamber, and the remaining Cu2+ was largely eliminated by algal uptake, contributing to an overall Cu2+ removal rate of 99.9% across the whole system. The nitrogen removal rate reached 79% in the system. The majority of the ammonium was assimilated by algae, and nitrogen oxides formed during the light period were denitrified at the cathode in the dark period. The variation in electrode potentials indicated that the cathode and anode potentials not only depended on the respective substrate concentrations, but also affected each other. The influence of algae on the microbial communities was greater than that of Cu2+ or the system structure. Devosia, Thauera, Pseudomonas, Acinetobacter and Flavobacterium may influence nitrogen removal, while Delftia, Thauera and Pseudomonas may play an important role in power generation. The present study has developed a practical method for removing pollutants from the wastewater containing heavy metals.
32. 题目: Biofilm Formation of Ancylobacter sp. TS-1 on different granular materials and its ability for chemolithoautotrophic As(III)-oxidation at high concentrations
期刊: Journal of Hazardous Materials
作者: Enzo Leiva-Aravena, Mario A. Vera, Robert Nerenberg, Eduardo D. Leiva, Ignacio T. Vargas
摘要: The oxidation of arsenic (As) is a key step in its removal from water, and biological oxidation may provide a cost-effective and sustainable method. The biofilm-formation ability of Ancylobacter sp. TS-1, a novel chemolithoautotrophic As oxidizer, was studied for four materials: polypropylene, graphite, sand, and zeolite. After seven days under batch mixotrophic conditions, with high concentrations of As(III) (225mg·L-1), biofilm formation was detected on all materials except for polypropylene. The results demonstrate As(III)-oxidation of TS-1 biofilms and suggest that the number of active cells was similar for graphite, sand, and zeolite. However, the biofilm biomass follows the specific surface area of each material: 7.0, 2.4, and 0.4mg VSS·cm-3 for zeolite, sand, and graphite, respectively. Therefore, the observed biofilm-biomass differences were probably associated with different amounts of EPS and inert biomass. Lastly, As(III)-oxidation kinetics were assessed for the biofilms formed on graphite and zeolite under chemolithoautotrophic conditions. The normalized oxidation rate for biofilms formed on these materials was 3.6 and 1.0mg·L-1·h-1·cm-3, resulting among the highest reported values for As(III)-oxidizing biofilms operated at high-As(III) concentrations. Our findings suggest that biofilm reactors based on Ancylobacter sp. TS-1 are highly promising for their utilization in As(III)-oxidation pre-treatment of high-As(III) polluted waters.
33. 题目: Excess sludge cell lysis by ultrasound combined with ozone
期刊: Separation and Purification Technology
作者: Ruiyang Zhang, Yuyu Mao, Liang Meng
摘要: Excess sludge is a by-product of sewage treatment. Due to its characteristics such as large volume, high moisture content, complex components and high processing cost, if not properly treated, it will cause extremely serious pollution to the surrounding soil, water and air, thus posing a threat to the ecological environment. Therefore, it is urgent to deal with it effectively. In this paper, excesssludge cell lysis by ultrasoundcombinedwith ozone was investigated. The optimal experimental conditions for excesssludge cell lysis with the ozone-ultrasonic process were explored. Results show that when the excess sludge concentration, ozone intake, ultrasonic power and frequency are 22000 mg/L, 7 L/min, 600 W, and 40 kHz respectively, ozone-ultrasonic process has the best effect on excesssludge cell lysis. Besides, mixed liquid suspended solids (MLSS), total organic carbon (TOC), solluted chemical oxigen demand (SCOD), sedimentation properties, NH3-H, protein, polysaccharide, fulvic acid and humic acid. were determined at different time under the optimal experimental conditions. Finally, the mechanism of excesssludge cell lysis by ozone-ultrasonic process was analyzed. The experiments carried out in this paper prove that ozone-ultrasonic process is an efficient cell lysis technology for excess sludge.
34. 题目: Long‐term water color and flow trends in the Mississippi River Headwaters, 1944–2010
期刊: Limnology and Oceanography
作者: Noah P. Germolus, Patrick L. Brezonik, Raymond M. Hozalski, Jacques C. Finlay
摘要: Intensification of brown color in surface waters has been observed over several decades in many areas. We examined a 64-yr daily record (1947–2010) of visual water color, a measure of chromophoric dissolved organic matter (CDOM), in the Mississippi River at Minneapolis, Minnesota. Although no monotonic trends in daily or mean annual color were evident, our analyses revealed trends in seasonal metrics, for example, mean winter color, on decadal scales related to changes in flow (hence climatic conditions). A pattern of high color (CDOM) in late spring and summer, corresponding with higher flow, was found across the period. Daily flow accounted for ~ 50% of the variance in color, and a lag of four days was found between peak responses of flow and color, supporting a CDOM source from wetlands in northern parts of the basin. The slope of the color-flow relationship increased over the 64 yr, driven by increased CDOM flushing in late summer-early fall. Based on trends in seasonally aggregated color and discharge, minimum and mean color and flow increased during winter over the 64 yr, potentially due to higher temperatures. Summer months did not show increases, but color became less variable. As a result, the color difference between summer and winter became smaller over the study period. During high flow events (ice-out or high precipitation), some hysteretic color patterns were observed consistent with observations on other large rivers. Our results indicate that long-term color (CDOM) trends in the Mississippi Headwaters reach are related to seasonally dominant changes in climatic conditions.
35. 题目: A sea change in microbial enzymes: Heterogeneous latitudinal and depth‐related gradients in bulk water and particle‐associated enzymatic activities from 30°S to 59°N in the Pacific Ocean
期刊: Limnology and Oceanography
作者: John Paul Balmonte, Meinhard Simon, Helge‐Ansgar Giebel, Carol Arnosti
摘要: Heterotrophic microbes initiate the degradation of high molecular weight organic matter using extracellular enzymes. Our understanding of differences in microbial enzymatic capabilities, especially among particle-associated taxa and in the deep ocean, is limited by a paucity of hydrolytic enzyme activity measurements. Here, we measured the activities of a broad range of hydrolytic enzymes (glucosidases, peptidases, polysaccharide hydrolases) in epipelagic to bathypelagic bulk water (nonsize-fractionated), and on particles (≥ 3 μm) along a 9800 km latitudinal transect from 30°S in the South Pacific to 59°N in the Bering Sea. Individual enzyme activities showed heterogeneous latitudinal and depth-related patterns, with varying biotic and abiotic correlates. With increasing latitude and decreasing temperature, lower laminarinase activities sharply contrasted with higher leucine aminopeptidase (leu-AMP) and chondroitin sulfate hydrolase activities in bulk water. Endopeptidases (chymotrypsins, trypsins) exhibited patchy spatial patterns, and their activities can exceed rates of the widely measured exopeptidase, leu-AMP. Compared to bulk water, particle-associated enzymatic profiles featured a greater relative importance of endopeptidases, as well as a broader spectrum of polysaccharide hydrolases in some locations, and latitudinal and depth-related trends that are likely consequences of varying particle fluxes. As water depth increased, enzymatic spectra on particles and in bulk water became narrower, and diverged more from one another. These distinct latitudinal and depth-related gradients of enzymatic activities underscore the biogeochemical consequences of emerging global patterns of microbial community structure and function, from surface to deep waters, and among particle-associated taxa.
36. 题目: Insight into the roles of electrolysis-activated persulfate oxidation in the waste activated sludge dewaterability: Effects and mechanism
期刊: Journal of Environmental Management
作者: Guanjun Wang, Dongdong Ge, Lu Bai, Yanting Dong, Chang Bian, Jiajia Xu, Nanwen Zhu, Haiping Yuan
摘要: Sludge dewatering, as one of the most important steps of sludge treatment, can facilitate transportation and improve disposal efficiency by reducing the volume of sludge. This study investigated the effects of electrolysis-activated persulfate oxidation on improving sludge dewaterability. The results indicated that the sludge capillary suction time (CST) and water content of dewatered sludge cake (Wc) reduced from 93.7 s and 87.8% to 9.7 s and 68.3% respectively at the optimized process parameters: electrolysis voltage of 40 V, electrolysis time of 20 min, and 1.2 mmol/g TS S2O82−. Correlation analysis revealed that the enhancement of sludge dewaterability was closely associated with the increased floc size and zeta potential, decreased protein content in three-layers extracellular polymeric substances (EPS) and viscosity (R = −0.868, p = 0.002; R = −0.703, p = 0.035; R ≥ 0.961, p < 0.001; R = 0.949, p < 0.001). Four protein fluorescence regions in EPS were analyzed by three-dimensional excitation-emission matrix parallel factor (3D-EEM-PARAFAC). The protein secondary structure was changed after the treatment, and the reduction of α-helix/(β-sheet + random coil) indicated that more hydrophobic sites were exposed. Analysis by X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) and rheological test demonstrated that the hydrophilic functional groups of the sludge were decreased and the sludge mobility was significantly enhanced after the treatment with electrolysis-activated persulfate oxidation. Moreover, bound water was converted to free water during SO4·− and ·OH generated by electrolysis-activated persulfate degraded EPS and attacked sludge cells. Meanwhile, scanning electron microscopy (SEM) images revealed that the treated sludge formed porous channel structures, which promoted the flowability of the water. These findings provide a new insight based on electrolysis-activated persulfate oxidation in sludge treatment for enhancing sludge dewaterability.
37. 题目: Haloacetic Acids Formation Potential of Tropical Peat Water DOM Fractions and Its Correlation with Spectral Parameters
期刊: Water, Air, & Soil Pollution
作者: Muammar Qadafi, Suprihanto Notodarmojo, Yuniati Zevi
摘要: Tropical peat water dissolved organic matter (DOM) fractions spectral parameters correlate with the formation of carcinogenic disinfection by-products (DBPs), haloacetic acids (HAAs). Peat water DOM has been fractionated using Superlite DAX-8, Amberlite XAD-4, and Amberlite IRA-958 resins to separate hydrophobic acid (HPOA), transphilic (TPH), hydrophilic-charged (HPIC), and hydrophilic-neutral (HPIN). The formation potential of HAA was determined using the total concentration of 5 HAAs (HAA5). The DOM characteristic was determined using dissolved organic carbon (DOC) and ultraviolet–visible (UV–Vis) absorbance was evaluated at 200–700 nm. The HPOA fraction dominates the DOM of tropical peat water with a 40% DOC concentration when the HPIC fraction was the slighter. The spectral absorbance ratios (E4/E6 and A253/A203) and spectral slopes (S206–213, S251–280, S281–295, and S>295) have a strong positive correlation with HAA5 formation potential (HAA5FP). Similarly, the absorbance ratio A210/A254 and spectral slopes S200–205 are strongly correlated to HAA5FP, but in a negative direction. In contrast, the E2/E3 and A280/A350 spectral ratio, and spectral slopes (S214-227, and S228–250), has a weaker correlation with HAA5FP. The E2/E3 and A280/A350 ratios and S251–280 S200–205 spectral slope show a strong relationship with the brominated HAA5FP (B-HAA5FP). The spectral parameters of DOM fractions can be used as surrogate parameters of HAA5FP of peat water.
38. 题目: CO2 capture by adsorption on biomass-derived activated char: A review
期刊: Science of The Total Environment
作者: Chirag Goel, Sooraj Mohan, P. Dinesha
摘要: Carbon capture and storage has been recognized as the most promising method for CO2 control. Among the many sorbents, char derived from pyrolysis and hydrothermal carbonization (HTC) of biomass have demonstrated excellent CO2 adsorption capability. This paper reviews the different parameters to produce a higher yield of biochar and hydrochar suitable for carbon sequestration. The mechanism of physisorption and chemisorption is briefly presented. The different kinetic models, diffusion models to describe adsorption mechanism, and adsorption isotherms for CO2 uptake from biomass-derived hydrochar are reviewed. The different factors that affect the CO2 uptake are the type of activation, surface area and porosity, the ratio of activation agent to char, activation temperature, adsorption pressure and temperature, additives, and other physicochemical properties. The optimal conditions for CO2 uptake with chemical activation of KOH is a KOH/char ratio of 2-3, activation temperature of 700 °C, and an adsorption temperature below 50 °C.
39. 题目: Effect of biochar produced from sewage sludge on tomato (Solanum lycopersicum L.) growth, soil chemical properties and heavy metal concentrations
期刊: Journal of Environmental Management
作者: Paraskevi Velli, Ioanna Manolikaki, Evan Diamadopoulos
摘要: The addition of biochar, as shown in the literature, improves significantly the chemical and physical soil properties and plant growth. This study examined the effect of biochar, compost and the combination of them on growth, nutrient and heavy metal concentrations of tomato. Biochar (BC) was produced from sewage sludge by pyrolysis at the temperature of 300 °C. The pot trials were carried out under an open-side greenhouse for a total of four months and under four treatments. The treatments applied were: Untreated soil (Control); soil with 2% w/w biochar (BC–SS); soil with 2% w/w compost (Compost); a mixture of biochar and compost at a 2% w/w level (BC–SS + Compost). The application of biochar exhibited substantial improvement on several soil properties. Total organic carbon (TOC) of soil increased (67%–85%), as did the nitrate nitrogen (55%) and ammonium nitrogen (145%). Additionally, available phosphorus significantly increased (45.5%–54.5%) by the application of biochar with/without compost. Dry weight of the aboveground (stems) and belowground (roots) plant tissues increased as well, although tomato yield was not increased significantly. Concentration of heavy metals and trace elements in tomato tissues was quite low. Traces of chromium (Cr), nickel (Ni), and cobalt (Co) were found only in roots of those treated, while silicon (Si) was present in the roots and stems. Arsenic (As), molybdenum (Mo) and lead (Pb) were detected in all plant tissues, but their concentrations did not exceed the permissible levels established for vegetables. Furthermore, the concentration of arsenic (As) and lead (Pb) in fruits decreased by the addition of the amendments (12%–65%). In conclusion, the addition of sewage sludge biochar improved soil characteristics and plant growth. Yet, prior to its general use, factors such as the type of biomass, soil, rate of application and crop must always be taken into consideration.
40. 题目: Effect of round-shaped silver nanoparticles on the genetic and functional diversity of soil microbial community in soil and “soil-plant” systems
期刊: Applied Soil Ecology
作者: A. Macůrková, L. Maryška, B. Jindřichová, T. Drobníková, B. Vrchotová, R. Pospíchalová, K. Záruba, T. Hubáček, J. Siegel, L. Burketová, P. Lovecká, O. Valentová
摘要: Silver and silver nanoparticles (AgNPs) are extensively used as antimicrobial agents in various products and consequently enter the soil ecosystem, in which they accumulate and can have adverse effects on above and belowground organisms. Since the composition of the soil microbiome could have a significant impact on soil fertility, we focused, in this study, on the effect of AgNPs on soil microbial communities. We evaluated the biomass, plant growth-promoting activities, and microbial genetic (taxonomical) and functional diversity in the soil and the “soil-plant” system using chemical, microbiological, and molecular biological methods, especially qPCR, RFLP, and REP-PCR. By compiling the results of the applied assays, we were able to correlate the changes in genetic diversity with the changes in functional diversity and their impact on the composition of soil organic matter. The effect of AgNPs was predominantly dose-dependent, whereas the concentration 100 mg kgdw−1 had the highest effect on all followed parameters. From the taxonomical point of view, AgNPs had the most significant impact on the relative abundance of Bacteroidetes, which increased in a dose-dependent manner, and Firmicutes, which decreased in a dose-dependent manner, and they caused the predominance of Ascomycota among Fungi. These changes in taxonomic diversity result in a significant decrease in the functional diversity of the microbial communities. Especially for the concentration 100 mg kgdw−1, we detected a significant decrease in the ability of the microbial community to utilize simple carbon substrates, determined by Biolog EcoPlates. We detected also a significant alteration in enzyme activity. The activity of enzymes responsible for depolymerization of complex organic matter was in a dose-dependent manner increased, whereas the highest activity reach samples amended with AgNPs at 100 mg kgdw−1. All these changes result in the accumulation of simple organic matter, which could increase osmotic pressure and have severe consequences on soil fertility. In amended soils, we detected alterations of activity of plant growth-promoting bacteria, specifically in the production of indole-3-acetic acid, 1-aminocyclopropane-1-carboxylic acid deaminase, and siderophores. All these activities are related to mitigating abiotic stress. The presence of plants in experimental soil had both a mitigating and deepening effect on the toxicity of AgNPs. Both effects probably relate to the influence of AgNPs on the selection of different microbial communities in the soil and the “soil-plant” system.