121. 题目: Ferrate Preoxidation Alleviating Membrane Fouling through the Formation of a Hydrophilic Prefiltration Layer
期刊: ACS ES&T Engineering
作者: Hai-Yang He, Wei Qiu, Yu-Lei Liu, Shu-Yue Xu, Jun Ma, Lu Wang
摘要: Membrane fouling is one of the main obstacles impacting ultrafiltration (UF) membranes for water purification. Herein, it was found that a hydrophilic layer that is composed of a ferric floc formed in the reduction of ferrate coated on the membrane during the ultrafiltration of river water, and this layer is effective for attenuating membrane fouling. The newly formed ferric (hydro)oxide particles aggregated with natural organic matter (NOM) of the source water and then deposited on the membrane surface forming a negatively charged, porous, and hydrophilic prefiltration layer. This layer was beneficial for rejecting transphilic dissolved organic carbon (DOC), resulted in the accumulation of external membrane foulants, and alleviated internal membrane fouling. The membrane flux improved by 2.8 times, and the membrane fouling resistance decreased by 0.36 times after preoxidation with 1.5 mg/L of ferrate. Meanwhile, the performance of the membrane rejection was enhanced by this layer as well. DOC and UV254 were eliminated by 41% and 67% at the condition of 2.0 mg/L ferrate preoxidation coupled with UF. A model analysis suggested that intermediate and standard pore blocking were enhanced after ferrate preoxidation, while cake layer fouling was substantially attenuated. The ferric prefiltration layer can be back-washed for the recovery of membrane flux and be repeatedly generated through ferrate preoxidation. The combination of ferrate preoxidation with UF takes full advantage of the oxidizability of ferrate and the aggregation/adsorption potential of ferric (hydro)oxides by the reduction of ferrate.
122. 题目: Effects of seagrass overgrazing on sediment erosion and carbon sink capacity: Current understanding and future priorities
期刊: Limnology and Oceanography Letters
作者: Martin Dahl, Mats Björk, Martin Gullström
摘要: We searched the literature for experimental and observational studies assessing the effects of seagrass overgrazing on erosion of sediment and sedimentary organic carbon (SOC) and found that most studies reported a significant impact, likely caused by a cascading effect (i.e., seagrass shoot loss → belowground biomass degradation → sediment destabilization or SOC erosion). However, there appears to be a clear lack of knowledge on the extent and mechanisms behind SOC erosion in seagrass meadows and we highlight the need for research to (1) define spatial and temporal scales of occurrence; (2) assess the influence of belowground biomass degradation, sediment characteristics, and hydrodynamic exposure on sediment stabilization; and (3) estimate the greenhouse gas emission after a disturbance. Such information would help coastal resource managers to address the causes and effects of SOC loss and sediment erosion when evaluating impacts of global change on coastal ecosystems.
123. 题目: Biochar for asphalt modification: A case of high-temperature properties improvement
期刊: Science of The Total Environment
作者: Feng Ma, Jiasheng Dai, Zhen Fu, Chen Li, Yalu Wen, Meng Jia, Yujie Wang, Ke Shi
摘要: Biochar has been utilized as a renewable biomass resource to develop sustainable and eco-friendly pavements. This study focuses on the influence of biochar as an asphalt modifier on the improvement of high-temperature performance of asphalt. A series of tests were performed to comprehensively evaluate the high-temperature performance of the biochar modified binder. The interaction mechanism between the biochar and the binder was explored using scanning electron microscopy and Fourier-transform infrared spectroscopy (FTIR). The results indicated that the complex modulus and penetration of the biochar-modified asphalt binder could be increased by up to 35% and 36.5%, respectively, compared with those in case of the matrix asphalt, thereby improving the deformation resistance. In addition, the observed increase in the complex modulus, rutting factor, and viscosity–temperature index contributed to the improvement of temperature sensitivity and anti-rutting properties. These relationships are attributed to the fact that biochar has a fibrous porous structure and forms a skeleton and stiffening zone in the binder. Although biochar has a negative effect on the low-temperature properties of the binder, this can be alleviated by controlling the biochar content. Moreover, the FTIR results showed that no new chemical functional groups appeared after the incorporation of biochar into the binder. The internal chemical environment of the biochar-modified asphalt binder was different from that of the matrix asphalt. In conclusion, biochar is feasible as a modifier for binders owing to its high-temperature properties.
124. 题目: Insight into the effects of regulating denitrification on composting: strategies to simultaneously reduce environmental pollution risk and promote aromatic humic substance formation
期刊: Bioresource Technology
作者: Mingzi Shi, Chengguo Liu, Yue Zhao, Zimin Wei, Maoyuan Zhao, Liming Jia, Pingping He
摘要: Denitrification during composting is a hidden danger that causes environmental pollution risk and aromatic humic substance damage, which needs to be better regulate urgently. In this study, two denitrification regulation methods, moisture and biochar amendment, were conducted during chicken manure composting. Denitrification performance data showed two regulation methods obviously reduced NO3−-N, NO2−-N and N2 contents. Humic substance increased by 25.3 % and 29.1 % under two regulations. Microbiological analysis indicated that two regulation methods could decreasing denitrifying functional microbes with aroma degradation capability. Subsequently, denitrification gene narG, nirS, nosZ were significantly inhibited (p<0.05) and the aromatic degradation metabolism pathways were down-regulated. Correlation analysis further revealed the important influence of interspecific interactions and non-biological characteristics on functional microbes. These results provided important scientific basis to denitrification regulation in the practice of composting, which achieved the purpose of simultaneously controlling environmental pollution risk and conducing end-product formation.
125. 题目: Effect of nickel salts on the production of biochar derived from alkali lignin: Properties and applications
期刊: Bioresource Technology
作者: Wenli Wang, Yichen Liu, Yue Wang, Longfei Liu, Changwei Hu
摘要: The massive generation of alkali lignin, has aroused the attention of all walks of life, and an eco-friendly utilization approach needs to be exploited. Herein, a simple pretreatment method with nickel salts was developed for the valorisation of alkali lignin through slow pyrolysis. The pretreatment of nickel salts improved the foaming or swelling behaviors of alkali lignin upon heating, and the specific surface area and total pore size of biochars increased about thirteenfold and eighteenfold, respectively. Additionally, Ni0 particles were generated and embedded in the carbon matrix of biochars. The biochar from Ni(NO3)2 pretreated lignin catalyzed the selective hydrogenation of nitrobenzene, yielding 80.5% of aniline; and that from (CH3COO)2Ni pretreated lignin showed adsorption capacity of lead around 87.1mg/g. Moreover, the NiCl2 pretreatment contributed to the formation of 1,2-dihydroxybenzene, while Ni(SO4)2 was conducive to the production of 4-methylguaiacol.
126. 题目: Particle size and fertilization regime shifts chemical composition and oxidation state of soil organic matter: Long‐term paddy field study
期刊: European Journal of Soil Science
作者: Mingrui Yan, Xiuzhi Zhang, Kailou Liu, Yilai Lou, Yidong Wang
摘要: The chemistry of soil organic matter (SOM) is critical for soil functions. However, the chemical composition and oxidation state of physical SOM fractions under long-term mineral and organic amendments in paddy soil are still unclear. Here, we investigated this issue with three particle size classes under five 37-years fertilization regimes in a subtropical paddy soil using pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS). Coarse particulate organic matter (cPOM, >250 μm), fine POM (fPOM, 53–250 μm) and mineral-associated OM (MOM, <53 μm) were isolated. Five fertilization regimes were unfertilized (control), nitrogen (N, urea), nitrogen+phosphorus+potassium (NPK, urea+Ca(H2PO4)2+KCl), NPK+straw (NPKS) and NPK+pig manure (NPKM). After the 37-years experiment, the SOM of control, N, NPK, NPKS and NPKM increased by 16.3%, 12.3%, 31.6%, 41.7% and 59.8% compared with the initial level, respectively. The pools of soil organic carbon (SOC) and total N as well as C/N ratio in soil matrix were localized by particle size, with mainstay in the MOM. Particle size, not fertilization regime, primarily shifted the chemical composition of SOM, with selective preservation of lignin and polysaccharides in the POM and enrichments of lipids and N-containing compounds in the MOM. The origin (plant- and microbial-derived) and oxidation state of SOM were also regulated by particle size (especially the coarse particles) but not fertilization. Despite of long-term persistence, the MOM had lower C oxidation state (implying higher vulnerability to microbial utilization) than the cPOM and fPOM. In conclusion, fertilization regime regulated the SOM (SOC & TN) pool, whereas physical particle size generated a divergence trend in the chemical composition and oxidation state of SOM in paddy soil, indicating the greater role of physical arrangement in SOM chemistry than the quality of amendments.
127. 题目: Investigating the effects of biochar colloids and nanoparticles on cucumber early seedlings
期刊: Science of The Total Environment
作者: Guocheng Liu, Meiqi Pan, Jiaying Song, Mengyao Guo, Lina Xu, Yanjun Xin
摘要: Understanding about the influence of biochar colloidal and nanoscale particles on plant is limited. We therefore extracted the colloids and nanoparticles from hot pepper stalk biochar (CB600 and NB600), and examined physiological responses of cucumber early seedlings through hydroponic culture and pot experiment. CB600 had no significant effect on shoot at 500 mg/L, while it decreased root biomass and inhibited lateral root development. The biomass and root length, area, and tip number dramatically reduced after 500 mg/L NB600 treatment. Water content of NB600-exposed shoot was lower, suggesting water uptake and transfer might be hindered. For resisting exposure stress, root hair number and length increased. Even, the study observed swelling and hyperplasia of root hairs after direct exposure of CB600 and NB600. These adverse effects might be associated with the contact and adhesion of CB600 and NB600 with sharp edges to root surface. For a low concentration of 50 mg/L, NB600 did not influence cucumber early seedlings. In soil, CB600 and NB600 did not cause inhibitory effect at relatively high contents of 500 mg/kg and 2000 mg/kg. This study provides useful information for understanding phytotoxicity and environmental risk of biochar colloids and nanoparticles, which has significant implications with regard to biochar application safety.
128. 题目: Enzymic moderations of bacterial and fungal communities on short- and long-term warming impacts on soil organic carbon
期刊: Science of The Total Environment
作者: Hui Wang, Jinquan Li, Hongyang Chen, Hao Liu, Ming Nie
摘要: Microbial communities play critical roles in soil carbon-warming feedback, but our understanding of their linkages to soil carbon (C) pools in response to short- and long-term warming is deficient. Here, by conducting a meta-analysis of 150 studies, we show that short-term (<5 years) warming mainly affects soil labile carbon (LC) pools by changing bacterial community structure, while long-term (≥5 years) warming promotes the decomposition of recalcitrant C (RC) pools by increasing fungal biomass and decreasing actinobacterial biomass. Specifically, under short-term warming, significant increases in actinobacterial biomass (+15.9%) and the G+/G- ratio (+8.0%) were accompanied by an increase in carbon-degrading enzyme activities and a decrease in LC (−5.9%). Under long-term warming, the fungal biomass (+20.4%) and related POX (phenol oxidase) activity (+34.9%) increased significantly, while actinobacterial biomass (−20.1%), RC (−18.8%) and SOC (−6.7%) decreased. Meanwhile, we observed that warming impacts on soil microbial communities can be predicted by ecosystem type, the magnitude of warming, pH and elevation. Latitude and warming duration contributed the most to explaining the responses of LC and RC, respectively, across studies. Given that RC accounts for a substantial fraction of global soil C pools, the decline in RC pools greatly contributes to soil C degradation. Our findings suggest that different microbial groups may mediate the temporal dynamics of the decomposition of different soil C components and highlight that incorporating the temporal responses of soil microorganisms will improve predictions of the long-term dynamics of soil C pools in a warmer world.
129. 题目: Molecular characteristics of biochar-derived organic matter sub-fractions extracted by ultrasonication
期刊: Science of The Total Environment
作者: S.J. Li, C.B. Xu, S. Qin, X. Guo, Y.C. Bai, F. Guo
摘要: Biochar-derived organic matter is key to carbon dynamics and pollutant transport in soils remediated by biochar. A limited understanding of the molecular composition of biochar-derived organic matter limits the ability to accurately predict the chemical cycle within soil and how biochar-derived organic matter will interact with contaminants. To describe the relatively comprehensive structure information of soybean straw biochar-extractable organic matter (BEOM) at the molecular level, we used solvents of different polarities, namely, petroleum ether (PE), carbon disulfide (CS2), methanol (CH3OH) and acetone (CH3COCH3), to extract organic samples from soybean straw biochar and used Fourier transform ion cyclotron resonance mass spectrometry (FTICR MS) for analysis. We found that a high percentage of unique molecular formulas were extracted by each solvent. This molecular diversity is mainly due to variance in solvent polarity and various intermolecular bonds destroyed by different solvents. The molecular signatures of the sub-fractions reveal that some recalcitrant BEOM sub-fractions will be easily released in the environment and preserved for a long time in the soil environment, while the majority of the labile BEOM sub-fractions tend to be preserved in the biochar itself. In addition, the most readily available organic N and S in biochar will be primarily released. These results reveal that biochar could provide nutrients efficiently and maintain soil organic carbon over the long term, suggesting that biochar is a promising material for soil improvement. By using high-resolution mass spectrometry, we revealed the BEOM signature at the molecular level in various possible environmental processes, which provides a theoretical basis for further research on the interactions between BEOM and organic contaminants.
130. 题目: The molecular differences of young and mature landfill leachates: Molecular composition, chemical property, and structural characteristic
作者: Jie Liu, Zhepei Gu, Xiqin Wang, Qibin Li
摘要: Landfill leachate is a highly contaminated and complex organic wastewater. It can be categorized into young (YL) and mature leachate (ML) based on the landfill age, with significant differences in the composition of organic matter, resulting from the significant differences in humification degree. To compare the organic composition of YL and ML, ESI FT-ICR MS was applied to systematically investigate their molecular composition, chemical properties, and structural characteristics. The molecular weight of YL organics was lower than that of ML organics. In addition, O/C and H/C distributions of YL and ML organics were significantly different. YL mainly consisted of CHO compounds and aliphatic compounds. ML mainly consisted of CHON compounds and high oxygen highly unsaturated and phenolic compounds. The unsaturation degree of YL organics was expressed by carbon double bond equivalents ((DBE-C)/C = −0.0336) and was not significantly different from that of ML (−0.0241), but nominal oxidation state of carbon (NOSC = −0.8010) and aromaticity (AImod = 0.1254) of YL were significantly lower than of ML (NOSC = −0.0692; AImod = 0.2464). In addition, YL and ML organics were rich in functional groups, but the YL organics contained more straight-chain structures. The ML organics contained fewer straight-chain structures, a larger number of benzene-ring structures, and more oxygen-containing functional groups. The more complex structural properties of ML organics may be the result of the transformation of YL organics after a long series of reactions, including electrocyclization, decarboxylation, and hydrogen abstraction reactions, which eventually increased the humification degree of leachate organic matter.
131. 题目: Microbial investigations of new hydrogel-biochar composites as soil amendments for simultaneous nitrogen-use improvement and heavy metal immobilization
期刊: Journal of Hazardous Materials
作者: Lixun Zhang, Yuntao Guan
摘要: Agricultural sustainability is challenging because of increasingly serious and co-existing issues, e.g., poor nitrogen-fertilizer use and heavy metal pollution. Herein, we introduced a new poly(acrylic acid)-grafted chitosan and biochar composite (PAA/CTS/BC) for soil amendment, and provided a first microbial insight into how PAA/CTS/BC amendment simultaneously improved nitrogen cycling and immobilized heavy metals. Our results suggest that the PAA/CTS/BC amendment significantly promoted soil ammonium retention, and reduced nitrate accumulation, nitrous oxide emission and ammonia volatilization during the rice cultivation. The availability of various heavy metals (Fe, Mn, Cu, Zn, Ni, Pb, Cr, and As) markedly decreased in the PAA/CTS/BC amended soil, thereby reducing their accumulation in rice root. The PAA/CTS/BC amendment significantly altered the structure and function of soil microbial communities. Importantly, the co-occurrence networks of microbial communities became more complex and function-specific after PAA/CTS/BC addition. For example, the keystone species related to organic matter degradation, denitrification, and plant resistance to pathogen or stresses were enriched within the network. In addition to direct adsorption, the effects of PAA/CTS/BC on shaping microbial communities played dominant roles in the soil amendment. Our findings provide a promising strategy of simultaneous nitrogen-use improvement and heavy metal immobilization for achieving crop production improvement, pollution control, and climate change mitigation.
132. 题目: Green remediation of benzene contaminated groundwater using persulfate activated by biochar composite loaded with iron sulfide minerals
期刊: Chemical Engineering Journal
作者: Jin Zhu, Yinan Song, Liuwei Wang, Zhuorong Zhang, Jing Gao, Daniel C.W. Tsang, Yong Sik Ok, Deyi Hou
摘要: In this study, biochar supported iron sulfide (FexSy) composite (FexSy@biochar) was synthesized and utilized as a persulfate (PS) activator for benzene removal from contaminated groundwater. The FexSy@biochar/PS system exhibited excellent performance in benzene adsorption and subsequent degradation. The optimal conditions for benzene removal in this study were found to be 1 g L-1 FexSy@biochar dosage and 3 mM PS concentration (removal rate 99.8%), with no reversible desorption of benzene concentrations in a long-time interval. The high catalytic performance of FexSy@biochar was mainly attributed to the free radicals −(i.e., SO4•−,·OH) generated from PS activation induced by FexSy particles on biochar, followed by the possible activation by oxygen-containing groups. The as-prepared FexSy@biochar also showed long-term effectiveness for PS activation as confirmed by the 4 test cycled tests. The EPR not only demonstrated the presence of·OH and SO4•− free radicals but also indicated the sustainable release effect of reactive species from FexSy@biochar/PS system, as strong signals were observed in the FexSy@biochar/PS system even after 24 h. The FexSy@biochar could be an alternative to existing activators of in-situ chemical oxidation for contaminated groundwater remediation.
133. 题目: Organic matter chemistry drives carbon dioxide production of peatlands
期刊: Geophysical Research Letters
作者: A.E. Normand, B.L. Turner, L.J. Lamit, A.N. Smith, B. Baiser, M.W. Clark, C. Hazlett, E.S. Kane, E. Lilleskov, J.R. Long, S.P. Grover, K.R. Reddy
摘要: Peatlands play a critical role in the global carbon (C) cycle, encompassing approximately 30% of the 1500 Pg of C stored in soils worldwide. However, this C is vulnerable to climate and land-use change. Ecosystem models predict the impact of perturbation on C fluxes based on soil C pools, yet responses could vary markedly depending on soil organic matter (SOM) chemistry. Here, we show that one SOM functional group responds strongly to environmental factors and predicts the risk of carbon dioxide (CO2) release from peatlands. The molecular composition of SOM in 125 peatlands differed markedly at the global scale due to variation in temperature, land-use, vegetation, and nutrient status. Despite this variation, incubation of peat from a subset of 11 sites revealed that O-alkyl C (i.e. carbohydrates) was the strongest predictor of aerobic CO2 production. This explicit link provides a simple parameter that can improve models of peatland CO2 fluxes.
134. 题目: Contaminants in biochar and suggested mitigation measures - a review
期刊: Chemical Engineering Journal
作者: Huawen Han, Wolfram Buss, Yuanzhang Zheng, Peizhi Song, Muhammad Khalid Rafiq, Pu Liu, Ondřej Mašek, Xiangkai Li
摘要: Biochars produced by pyrolysis at high temperatures under oxygen limited conditions can contain both well-known contaminants (polycyclic aromatic hydrocarbons (PAHs), potentially toxic elements (PTEs), dioxins, volatile organic compounds (VOCs)) and emerging contaminants (e.g., persistent free radicals, metal cyanide). Their potential to induce phytotoxicity, cytotoxicity, and neurotoxicity highlight the need to establish effective strategies to control and eliminate contaminants for sustainable biochar use. Although some articles have reviewed the ecotoxic potential of biochar in relation to some of these contaminants, strategies to mitigate the whole suite of contaminants potentially present in biochar have not been systematically reviewed so far. This review discusses (i) the formation mechanism of such contaminants and (ii) evaluates their potential risk to ecosystems, a prerequisite (iii) to understand and explore effective control strategies for producing biochars with minimum contamination. A pyrolysis unit design where pyrolysis liquids and solids are fully separated following the pyrolysis zone and optimization of pyrolysis parameters ensures organic contaminants in the pyrolysis liquids do not condense onto the biochar. Post-production treatments, such as thermal treatment or natural and artificial ageing help organic contaminant removal and breakdown. Co-pyrolysis of metal-rich feedstock with metal-free biomass is the only way of reducing total PTE levels, though available PTE levels are low in biochars and decrease further with pyrolysis temperature. More specific strategies for reducing the concentration of individual contaminants are discussed in the review. With our proposed recommendations, biochars with little risk for the environment can be produced.
135. 题目: Organic amendments affect soil organic carbon sequestration and fractions in fields with long-term contrasting nitrogen applications
期刊: Agriculture, Ecosystems & Environment
作者: Xiushuang Li, Wenling Zhu, Fengyi Xu, Junli Du, Xiaohong Tian, Jianglan Shi, Gehong Wei
摘要: Organic amendments are widely used to both manage soil organic C (SOC) and improve soil fertility in agro-ecosystems. However, crop production and the mechanisms of SOC sequestration following organic amendment may be affected by long-term differential N fertilizations, hence driving the dynamics in SOC fractions in cultivated fields. Our 3-yr (2016–2019) field experiment evaluated the responses of SOC sequestration and SOC fractions to organic amendments in soils with long-term contrasting N applications in a winter wheat monoculture system. We compared wheat straw return (St) and farmyard manure application (Fm) in soils with either long-term (2002–2019) N absence (-N) or normal N application (+N). Both St and Fm increased SOC stocks in the 0–20-cm layer, but Fm increased it more than St did. However, St exhibited a greater SOC sequestration rate in +N soils than that in –N soils, whereas Fm exhibited both a lower SOC sequestration rate and efficiency in +N soils than in –N soils. SOC increased across all fractions in all soils after both St and Fm. However, compared with –N soils, +N soils exhibited a lower SOC increase, specifically in the very labile fraction after St, but in the non-labile fraction after Fm. St, Fm, and +N all increased the soil C management index (CMI), but only +N increased wheat yield and its sustainable yield index (SYI). Those relationships indicated that both straw and manure amendments were responsible for both SOC sequestration and increasing the CMI, and N input was fundamentally responsible for an increased SYI and associated plant-C input. Consequently, straw return was expected to be more effective at sequestering SOC when applied to soil having had adequate long-term N application, whereas farmyard manure application was likely more effective when applied in N-deficient soil. Our field study findings provide empirical evidence that soil N availability affects SOC sequestration capacities following organic amendments, and that impacts strategies aimed at further increasing soil fertility improvements via organic amendment, especially considering that different agro-ecosystems are subject to different fertilization regimes.
136. 题目: Potential application of machine learning for exploring adsorption mechanisms of pharmaceuticals onto biochars
作者: Xuan Cuong Nguyen, Quang Viet Ly, Thi Thanh Huyen Nguyen, Hien Thi Thu Ngo, Yunxia Hu, Zhenghua Zhang
摘要: The increasing accumulation of pharmaceuticals in aquatic ecosystems could impair freshwater quality and threaten human health. Despite the adsorption of pharmaceuticals on biochars is one of the most cost-effective and eco-friendly removal methods, the wide variation of experimental designs and research aims among previous studies pose significant challenge in selecting biochar for optimal removal. In this work, literature data of 1033 sets with 21 variables collected from 267 papers over ten years (2010–2020) covering 19 pharmaceuticals onto 88 biochars were assessed by different machine learning (ML) algorithms i.e., Linear regression model (LM), Feed-forward neural networks (NNET), Deep neutral networks (DNN), Cubist, K-nearest neighbor (KNN), and Random forest (RF), to predict equilibrium adsorption capacity (Qe) and explore adsorption mechanisms. LM showed the best performance on ranking importance of input variables. Except for initial concentration of pharmaceuticals, Qe was strongly governed by biochars' properties including specific surface area (BET), pore volume (PV), and pore structure (PS) rather than pharmaceuticals’ properties and experimental conditions. The most accurate model for estimating Qe was achieved by Cubist, followed by KNN, RF, KNN, NNET and LM. The generalization ability was observed by the tuned Cubist with 26 rules for the prediction of the unseen data. This study not only provides an insightful evidence for data-based adsorption mechanisms of pharmaceuticals on biochars, but also offers a potential method to accurately predict the biochar adsorption performance without conducting any experiments, which will be of high interests in practice in terms of water/wastewater treatment using biochars.
137. 题目: Enhanced Sludge Dewaterability by a Novel MnFe2O4-Biochar Activated Peroxymonosulfate Process Combined with Tannic Acid
期刊: Chemical Engineering Journal
作者: Xian Yang, Liuting Zeng, Jinjia Huang, Zhihua Mo, Zhijie Guan, Shuiyu Sun, Jialin Liang, Shaosong Huang
摘要: The high moisture content of sludge is a key factor limiting its subsequent treatment and disposal. Herein, a novel method of MnFe2O4-biochar (MFB) activated peroxymonosulfate (PMS) combined with tannic acid (TA) was conducted to improve sludge dewatering. The effects of different concentrations of MFB, PMS, and TA on waste activated sludge (WAS) dewaterability were investigated. The water content of sludge cake dropped to 40.80% when the initial pH was 5.0, and the concentration of PMS, MFB, and TA was 0.64 mM/g DS, 100 mg/g DS, and 0.12 mM/g DS respectively, demonstrating that MFB/PMS/TA could effectively enhance sludge dewaterability. Analyzing the changing of sludge properties and characterizing MFB confirmed that the enhancement of sludge dewaterability occurred in two phases. First, TA accelerated the valence transformation of Fe and Mn to promote PMS activation, which strengthened the oxidation capacity of the system. Second, TA complexed and precipitated protein to enhance the compressibility and dewaterability of sludge. Furthermore, MFB/PMS/TA treatment could increase the calorific value of treated sludge, and after the combined treatment, the sludge biochar also had a better pore structure, indicating that the sludge after the combined treatment posed a good prospect of resource utilization. These findings provide a novel strategy for the practical application of achieving efficient sludge deep dewatering, providing a valuable reference for downstream sludge utilization.
138. 题目: Biochar based photocatalyst for degradation of organic aqueous waste: A review
作者: Shubham Sutar, Sachin Otari, Jyoti Jadhav
摘要: The advancement in the treatment technology for wastewater containing recalcitrant pollutants to lower the overall cost and time of the treatment processes is the prime demand. Biochar (BC) based photocatalyst have proved their potential application in the photo-degradation of a wide range of organic pollutants. The structural and chemical properties of the BC enhance the efficacy of photocatalyst, improving its optical properties with increased stability. This review gives an overview of the progress that occurred during the last five years in BC-based photocatalyst for degradation of recalcitrant organic waste in the aqueous system, emphasizing the role of BC in the photocatalytic performance with a brief discussion regarding the various sources of BC and different strategies used to modify the BC. Further, the critical challenges are discussed, which would be confronted during the scaling up and real-time application in wastewater treatment.
139. 题目: Nitrogen addition promotes soil phosphorus availability in the subalpine forest of eastern Tibetan Plateau
期刊: Journal of Soils and Sediments
作者: Ye Liu, Haijian Bing, Yanhong Wu, He Zhu, Xin Tian, Zhiguo Wang, Ruiying Chang
摘要: Purpose The biogeochemical cycling of phosphorus (P) is essential for maintaining plant productivity and thus plays a vital role in soil carbon sequestration. However, how soil P availability responds to increasing atmospheric nitrogen (N) deposition in subalpine forests remains unclear. The aims of this study are to explore the responses of P bioavailability in the subalpine soils of eastern Tibetan Plateau to different N addition levels. Materials and methods A field experiment with three N addition gradients (0, 8, and 40 kg N ha−1 year−1) was performed in the Abies fabri dominated forest of Gongga Mountain, eastern Tibetan Plateau. The soil P fractions in organic layer and mineral layers (0–5, 5–10, 10–20 cm) were analyzed to reveal their responses to different N addition levels, and the key drivers regulating soil P availability under the N addition were also deciphered. Results and discussion The low N addition did not alter the concentrations of total P and its fractions in the soils, while the high N addition significantly increased the concentrations of bioavailable P (AP). The results of structure equation models suggest that the decrease in microbial biomass and energy demand (dissolved organic carbon, DOC) of microorganisms under high N addition probably promotes the turnover and release of organic P rather than P immobilization. Soil P fractions displayed a significant difference among the soil depths, while the N addition did not alter their vertical distribution patterns. Soil moisture, pH, soil organic carbon, DOC, and microbial biomass controlled the vertical distribution of AP, while the oxides or minerals of aluminum determined the variation in other P fractions. Conclusions High N deposition rate can promote soil P availability in the subalpine forest, while N addition did not alter the vertical distribution patterns of soil P, suggesting a strong regulation of initial conditions on its response sensitivity to N deposition. Although short-term N deposition dose not strongly alter soil P transformation in the subalpine forest, the varied availability of soil P needs to be concerned under the increasing N deposition rate in the future.
140. 题目: Effective leachate treatment by a pilot-scale submerged electro-membrane bioreactor
期刊: Environmental Science and Pollution Research
作者: Mohammad Heidari Farsani, Reza Jalilzadeh Yengejeh, Alireza Hajiseyed Mirzahosseini, Masoud Monavari, Amir hessam Hassani, Nezamaddin Mengelizadeh
摘要: Most landfill leachates contain organic compounds that cannot be easily separated by conventional biological processes. Recently, integration of membrane bioreactors and electro-oxidation has been proposed as a suitable option for the treatment and separation of organic and inorganic contaminants in leachate. Therefore, in the present study, the performance of submerged electro-membrane bioreactor (SEMBR) along with a conventional membrane bioreactor (MBR) on a pilot scale was evaluated for the treatment of leachate. Both bioreactors were used to compare treatment efficiency under the same conditions. The removal rates of chemical oxygen demand (COD), ammonia nitrogen (NH4+–N), phosphate (PO43−–P), color, UV254, and metals were investigated. The results showed that applying electric current to the MBR could approximately increase the COD removal efficiency from 94 to 98.5%; PO43−–P removal from 70 to 99%; NH3+–N removal from 91 to 99%; UV254 removal from 80 to 96%; and heavy metals removal from 40 to 95%. Humic acid removal efficiency as another indicator of humic substances was increased from 75% in the MBR to 96% in the SEMBR process. The results also showed that the effluent can be introduced into the wastewater treatment plant for further treatment. The SEMBR process achieved a minimization of fouling of membranes compared to conventional MBR. The consumption of the energy and electrode was in accordance with the previous results, and the required energy of 1.57 kWh/m3 of wastewater was calculated. The sludge volume index (SVI) in SEMBR (105 ml/g) was better than MBR (135 ml/g) due to the electrokinetic effect on the production of denser flocs. Based on the results, it can be concluded that the application of electric current can improve the performance of MBR in removing PO43−, NH4+, and membrane fouling.