过一硫酸盐体系中铜分布模式控制活性物种的产生和污染物降解路径

The distribution pattern of metals as active centers on a substrate can influence the peroxymonosulfate(PMS)activation and contaminants degradation.Herein,atomic layer deposition is applied to prepare Cu single atom(SA-Cu),cluster(C-Cu),and film(F-Cu)decorated MXene catalysts by regulating the number of deposition cycles.In comparison with SA-Cu-MXene(adsorption energy(E_(ads))=-4.236 eV)and F-Cu-MXene(E_(ads)=-3.548 eV),PMS is shown to adsorb preferably on the C-Cu-MXene surface for activation(E_(ads)=-5.435 eV),realizing higher utilization efficiency.More SO_(4)^(·-)are generated in C-Cu-MXene/PMS system with steady-state concentration and 1–3 orders of magnitude higher than those in the SA-Cu-MXene and F-Cu-MXene activated PMS systems.Particularly,the contribution of SO_(4)^(·-)oxidation to sulfamethoxazole(SMX)degradation followed the order,C-Cu-MXene(97.3%)>SA-Cu-MXene(90.4%)>FCu-MXene(71.9%),realizing the larger SMX degradation rate in the C-Cu-MXene/PMS system with the degradation rate constants(k)at 0.0485 min^(-1).Additionally,SMX degradation routes in C-Cu-MXene/PMS system are found with fewer toxic intermediates.Through this work,we highlighted the importance of guided design of heterogeneous catalysts in the PMS system.Appropriate metal distribution patterns need to be selected according to the actual water treatment demand.Metal sites could be then fully utilized to produce specific active species to improve the utilization efficiency of the oxidants.

可生物降解塑料取代传统塑料--对碳排放的影响

In recent years,a great deal of attention has been focused on the environmental impact of plastics,includ-ing the carbon emissions related to plastics,which has promoted the application of biodegradable plas-tics.Countries worldwide have shown high interest in replacing traditional plastics with biodegradable plastics.However,no systematic comparison has been conducted on the carbon emissions of biodegrad-able versus traditional plastic products.This study evaluates the carbon emissions of traditional and biodegradable plastic products(BPPs)over four stages and briefly discusses environmental and economic perspectives.Four scenarios-namely,the traditional method,chemical recycling,industrial composting,and anaerobic digestion-are considered for the disposal of waste BPPs(WBPPs).The analysis takes China as a case study.The results show that the carbon emissions of 1000traditional plastic products(plastic bags,lunch boxes,cups,etc.)were52.09-150.36 carbon emissions equivalent of per kilogram(kg CO_(2)eq),with the stage of plastic production contributing 50.71%-50.77%.In comparison,1000 similar BPPs topped out at 21.06-56.86 kg CO_(2)eq,approximately 13.53%-62.19%lower than traditional plastic prod-ucts.The difference was mainly at the stages of plastic production and waste disposal,and the BPPs showed significant carbon reduction potential at the raw material acquisition stage.Waste disposal plays an important role in environmental impact,and composting and anaerobic digestion are considered to be preferable disposal methods for WBPPs.However,the high cost of biodegradable plastics is a challenge for their widespread use.This study has important reference significance for the sustainable development of the biodegradableplastics industry.

Efficient production of ethyl levulinate from cassava over Al2(SO4)3 catalyst in ethanol–water system

One-pot achievement of ethyl levulinate from cassava was conducted in ethanol–water system over several simple sulfate salt catalysts. Al2(SO4)3catalyst had the best performance in synthesizing ethyl levulinate comparing with those of a series of sulfate salts. The highest yields of ethyl levulinate was up to 39.27% as well as 7.78% levulinate acid when cassava was catalyzed in ethanol medium by adding 10 wt% water.13C and1H NMR spectroscopic investigations confirmed that isomerization of glucose to fructose over Al2(SO4)3catalyst is an important step in producing ethyl levulinate and levulinate acid. Due to aggregations of Al3+under hydrothermal conditions, tiny amount of Al3+were detected in filtrate at the percentage of 0.32% even if in absolute water. Brønsted and Lewis acids could improve the yield of ethyl levulinate and levulinate acid by synergistic effect. All results suggested that Al2(SO4)3was a simple and efficient catalyst for ethyl levulinate and levulinate acid production. © 2016 Science Press

Review of ionospheric irregularities and ionospheric electrodynamic coupling in the middle latitude region

This paper briefly reviews ionospheric irregularities that occur in the E and F regions at mid-latitudes. Sporadic E(ES) is a common ionospheric irregularity phenomenon that is first noticed in the E layer. ES mainly appears during daytime in summer hemispheres, and is formed primarily from neutral wind shear in the mesosphere and lower thermosphere(MLT) region. Field-aligned irregularity(FAI) in the E region is also observed by Very High Frequency(VHF) radar in mid-latitude regions. FAI frequently occurs after sunset in summer hemispheres, and spectrum features of E region FAI echoes suggest that type-2 irregularity is dominant in the nighttime ionosphere. A close relationship between ES and E region FAI implies that ES may be a possible source of E region FAI in the nighttime ionosphere. Strong neutral wind shear, steep ES plasma density gradient, and a polarized electric field are the significant factors affecting the formation of E region FAI. At mid-latitudes, joint observational experiments including ionosonde, VHF radar, Global Positioning System(GPS) stations, and all-sky optical images have revealed strong connections across different scales of ionospheric irregularities in the nighttime F region, such as spread F(SF), medium-scale traveling ionospheric disturbances(MSTID), and F region FAI.Observations suggest that different scales of ionospheric irregularities are generally attributed to the Perkins instability and subsequently excited gradient drift instability. Nighttime MSTID can further evolve into small-scale structures through a nonlinear cascade process when a steep plasma density gradient exists at the bottom of the F region. In addition, the effect of ionospheric electrodynamic coupling processes, including ionospheric E-F coupling and inter-hemispheric coupling on the generation of ionospheric irregularities, becomes more prominent due to the significant dip angle and equipotentiality of magnetic field lines in the mid-latitude ionosphere. Polarized electric fields can map to different ionospheric regions and excite plasma instabilities which form ionospheric irregularities. Nevertheless,the mapping efficiency of a polarized electric field depends on the ionospheric background and spatial scale of the field.

Overview of Bio-Oil from Sewage Sludge by Direct Thermochemical Liquefaction Technology

Sewage sludge is an unavoidable secondary pollution produced in the process of sewage treatment. At present traditional methods of treating sludge (e.g. landfill, incineration or land application) have some disadvantages and shortages. Direct thermochemical liquefaction of sludge is a new treatment method, which has the advantage of both treatment and energy recovery. Research progress and application prospect of sludge liquefaction technology are widely reported, typical liquefaction process with bio-oil production and its main influencing factors are introduced. Besides, the devel- opment of this process is illustrated, and resource and energy recovery of this technology are pointed out to be the ten- dency of sludge treatment in the future.

Interactions of phenol and benzaldehyde in electrocatalytic upgrading process

Biomass pyrolysis oil can be improved effectively by electrocatalytic hydrogenation(ECH).However,the unclear interactions among different components lead to low bio-oil upgrading efficiency in the conversion process.Herein,benzaldehyde and phenol,as common compounds in bio-oil,were chosen as model compounds.The interactions between the two components were explored in the ECH process by combining experiments and theoretical calculations.Results showed that phenol could accelerate the conversion of benzaldehyde in the ECH.The selectivity of benzyl alcohol was increased from 60.9%of unadded phenol to 99.1%with 30 mmol/L phenol concentration at 5 h.Benzaldehyde inhibited the ECH of phenol.In the presence of benzaldehyde,the conversion rate of phenol was below 10.0%with no cyclohexanone and cyclohexanol formation at 5 h.The density functional theory(DFT)calculations revealed that the phenol could promote the adsorption of benzaldehyde and facilitate the targeted conversion of benzaldehyde on the active site by lowering the reaction energy barrier.The research on the interaction between phenol and benzaldehyde in the ECH provides a theoretical basis for the application of ECH in practical bio-oil upgrading.

Mitigating greenhouse gas emissions from municipal wastewater treatment in China

Municipal wastewater treatment plays an indispensable role in enhancing water quality by eliminating contaminants.While the process is vital,its environmental footprint,especially in terms of greenhouse gas(GHG)emissions,remains underexplored.Here we offer a comprehensive assessment of GHG emissions from wastewater treatment plants(WWTPs)across China.Our analyses reveal an estimated 1.54(0.92-2.65)×10^(4)Gg release of GHGs(CO_(2)-eq)in 2020,with a dominant contribution from N_(2)O emissions and electricity consumption.We can foresee a 60-65%reduction potential in GHG emissions with promising advancements in wastewater treatment,such as cutting-edge biological techniques,intelligent wastewater strategies,and a shift towards renewable energy sources.

State-of-the-art applications of machine learning in the life cycle of solid waste management

Due to the superiority of machine learning(ML)data processing,it is widely used in research of solid waste(SW).This study analyzed the research and developmental progress of the applications of ML in the life cycle of SW.Statistical analyses were undertaken on the literature published between 1985 and 2021 in the Science Citation Index Expanded and Social Sciences Citation Index to provide an overview of the progress.Based on the articles considered,a rapid upward trend from 1985 to 2021 was found and international cooperatives were found to have strengthened.The three topics of ML,namely,SW categories,ML algorithms,and specific applications,as applied to the life cycle of SW were discussed.ML has been applied during the entire SW process,thereby affecting its life cycle.ML was used to predict the generation and characteristics of SW,optimize its collection and transportation,and model the processing of its energy utilization.Finally,the current challenges of applying ML to SW and future perspectives were discussed.The goal is to achieve high economic and environmental benefits and carbon reduction during the life cycle of SW.ML plays an important role in the modernization and intellectualization of SW management.It is hoped that this work would be helpful to provide a constructive overview towards the state-of-the-art development of SW disposal.

Prediction of high-density polyethylene pyrolysis using kinetic parameters based on thermogravimetric and artificial neural networks

Pyrolysis is considered an attractive option and a promising way to dispose waste plastics.The thermogravimetric experiments of high-density polyethylene(HDPE)were conducted from 105℃ to 900℃ at different heating rates(10℃/min,20℃/min,and 30℃/min)to investigate their thermal pyrolysis behavior.We investigated four methods including three model-free methods and one modelfitting method to estimate dynamic parameters.Additionally,an artificial neural network model was developed by providing the heating rates and temperatures to predict the weight loss(wt.%)of HDPE,and optimized via assessing mean squared error and determination coefficient on the test set.The optimal MSE(2.6297×10^(−2))and R^(2) value(R^(2)>0.999)were obtained.Activation energy and preexponential factor obtained from four different models achieves the acceptable value between experimental and predicted results.The relative error of the model increased from 2.4%to 6.8%when the sampling frequency changed from 50 s to 60 s,but showed no significant difference when the sampling frequency was below 50 s.This result provides a promising approach to simplify the further modelling work and to reduce the required data storage space.This study revealed the possibility of simulating the HDPE pyrolysis process via machine learning with no significant accuracy loss of the kinetic parameters.It is hoped that this work could potentially benefit to the development of pyrolysis process modelling of HDPE and the other plastics.

New insight into the synergy of nitrogen-related sites on biochar surface for sulfamethoxazole adsorption from water

In-depth exploration of the relationship among different adsorption sites is conducive to design of efficient adsorbents for target pollutants removal from water.In this study,the experiments,multivariate non-linear regression and density functional theory calculations are applied to explore the possible synergistic effects of three nitrogen(N)-containing sites on cow dung biochar surface for sulfamethoxazole(SMX)adsorption.Notably,a strong synergistic effect between pyridinic N and pyrrolic N sites was found for sulfamethoxazole adsorption.The adsorption energies of SMX on four pyrrolic N-coupled pyridinic N structures were-1.02,-0.41,-0.49 and-0.72 e V,much higher than the sum of adsorption energies(-0.31 e V)on pyrrolic N and pyridinic N.Besides,the alteration of Mulliken charge revealed that the simultaneous presence of pyridinic N and pyrrolic N improved the electron transfer remarkably from-0.459 e and 0.094 e to-0.649 e and 0.186 e,benefiting for SMX adsorption.This work firstly explored the possible synergies of adsorption sites on biochar surface for organic contaminants removal from water,which shed new lights on the adsorption mechanism and provided valuable information to design efficient adsorbents in the field of water treatment.

Phosphorus-enriched biochar from biogas residue of Eichhornia crassipes:transformation and release of phosphorus

Pyrolysis is an effective technology for treating and utilizing biogas residue.To explore the phosphorus(P)supply capacity of the biochar generated from biogas residue of Eichhornia Crassipes,the P speciation of E.crassipes biogas residue and biomass during pyrolysis(300-700℃)was analyzed by combining sequential chemical extraction,31P nuclear magnetic resonance(NMR)and P K-edge X-ray absorption near edge structure(XANES)spectroscopy.Pyrolysis treatment promoted the conversion of amorphous Ca-P phases in biogas residue and biomass into crystalline hydroxyapatite(HAP)phase,which matched the formation of stable HCl-P pools in the biochar derived from biogas residue(AEBs,22.65-82.04%)and biomass(EBs,13.08-33.52%)in the process of pyrolysis.Moreover,the total P contents in AEBs(19.43-28.92 mg g^(−1))were higher than that of EBs(3.41-5.26 mg g^(−1)),indicating that AEBs had a great P reclamation potential.The P release kinetics from AEBs and EBs in water were evaluated via an incubation experiment for 360 h.The P release from both AEBs and EBs conformed to the pseudo-second order kinetics model(R^(2)>0.93),but their P release behaviors were different.The P release of AEBs conformed to the diffusion-re-adsorption model,while that of EBs accorded with the diffusion-dissolution model.The diffusive gradients in thin-films(DGT)analysis showed that AEBs could significantly increase soil available P content as compared with EBs.Hence,the biochar produced from biogas residue of E.crassipes via pyrolysis has a good application potential as a P fertilizer.

含水率及温度对中药渣热解特性影响

中药渣类高含水工业生物质废弃物能源化清洁处理技术开发尤为重要。本工作以中药渣为研究对象,结合热重表征手段,利用固定床对其进行热解特性研究。研究不同原料含水率、热解温度及热解速率下的热解产物产率分布及其成分和特性,及氮元素在气、液、固三相产物中分布规律。结果表明,该中药渣完全热解的温度范围为650~850℃。在此温度范围中升高温度有利于热解过程,提升了热解效率及可燃气品质,可燃气、半焦中的氮元素含量下降,热解油中的含量上升。降低含水率能够提高热解效率,热解油中含氮化合物含量增加,促使氮元素向液相迁移。中药渣烘干的过程中减少了碱金属含量,影响热解油组分。提高热解速率也能一定程度上影响热解产物组分及氮元素分布。本研究可为中药渣热解过程优化及含氮化合物排放控制提供理论基础。

污泥中重金属处理方法

污泥特别是燃煤电厂脱硫废水污泥中的重金属严重超标,属于危险固体废物。据统计,我国市政污泥年产量已经突破5000万吨,脱硫废水污泥每年产量更是高达9000万吨,如果不进行妥当的重金属处置,会造成严重的二次污染和环境健康风险。本文介绍了污泥处理的国内外现状和污泥重金属的测定及评价方法,并从原理、反应装置、研究进展和热点等方面详细总结了化学法、电动法、生物法、热处理法和稳定化法的优缺点,阐明了各种方法中的现存问题和发展前景,最后对多方法联合方案提出了前景展望。

微生物修复石油烃土壤污染技术研究进展

随着人民生活水平的提高,环境保护问题愈发受到人们重视。其中石油烃的土壤污染因其持续时间长、污染去除难度大而受到广泛关注。在各类修复技术中,原位微生物修复强化技术因其成本较低、环境影响小、无二次污染、可原位修复的特点成为了当前的技术热门。文中综述了生物投加法、生物刺激法、联合修复法等原位微生物修复技术,并介绍了一些典型工程案例,为原位微生物修复强化技术的选择及工程应用提供了参考,并对未来原位微生物修复强化技术的研究重点进行了展望。

Overcoming oral insulin delivery barriers： application of cell penetrating peptide and silica-based nanoporous composites

Oral insulin delivery has received the most attention in insulin formulations due to its high patient compliance and, more importantly, to its potential to mimic the physiologic insulin secretion seen in non-diabetic individuals. However, oral insulin delivery has two major limitations： the enzymatic barrier that leads to rapid insulin degradation, and the mucosal barrier that limits insulin＇s bioavailability. Several approaches have been actively pursued to circumvent the enzyme barrier, with some of them receiving promising results. Yet, thus far there has been no major success in overcoming the mucosal barrier, which is the main cause in undercutting insulin＇s oral bioavailability. In this review of our group＇s research, an innovative silica-based, mucoadhesive oral insulin formulation with encapsulated-insulin/cell penetrating peptide （CPP） to overcome both enzyme and mucosal barriers is discussed, and the preliminary and convincing results to confirm the plausibility of this oral insulin delivery system are reviewed. In vitro studies demonstrated that the CPPinsulin conjugates could facilitate cellular uptake of insulin while keeping insulin＇s biologic functions intact. It was also confirmed that low molecular weight protamine （LMWP） behaves like a CPP peptide, with a cell translocation potency equivalent to that of the widely studied TAT. The mucoadhesive properties of the produced silica-chitosan composites could be controlled by varying both the pH and composition; the composite consisting of chitosan （25wt-%） and silica （75 wt-%） exhibited the greatest mucoadhesion at gastric pH. Furthermore, drugrelease from the composite network could also be regulated by altering the chitosan content. Overall, the universal applicability of those technologies could lead to development of a generic platform for oral delivery of many other bioactive compounds, especially for peptide or protein drugs which inevitably encounter the poor bioavailability issues.

Spillover effect of environmental investment： evidence from panel data at provincial level in China

This paper considers pollution density as a function of environmental investment. The higher envir- onmental investment, the lower pollution density. The lower the pollution density is the higher production technology becomes. This is called the spillover effect. We collected China＇s panel data at the provincial level from 2005 to 2009, and tested the spillover effect of environmental investment. This paper finds that the environmental investment influenced production technology positively. There is a significant positive relation between government expenditure and spillover effect.

Ultrasound-mediated targeted microbubbles： a new vehicle for cancer therapy

With the hope of overcoming the serious side effects, great endeavor has been made in tumor-targeted chemotherapy, and various drug delivery modalities and drug carriers have been made to decrease systemic toxicity caused by chemotherapeutic agents. Scientists from home and abroad focus on the research of targeted microbubbles contrast agent, and the use of the targeted ultrasound microbubble contrast agent can carry gene drugs and so on to the target tissue, as well as mediated tumor cell apoptosis and tumor microvascular thrombosis block, etc., thus plays the role of targeted therapy. Recent studies have elucidated the mechanisms of drug release and absorption, however, much work remains to be done in order to develop a successful and optimal system. In this review, we summarized the continuing efforts in under-standing the usage of the ultrasound triggered target microbubbles in cancer therapy, from release mechanism to preparation methods. The latest applications of ultra-sound-triggered targeted microbubbles in cancer therapy, especially in gene therapy and antiangiogenic cancer therapy were discussed. Moreover, we concluded that as a new technology, ultrasound-triggered targeted microbubbles used as drug carriers and imaging agents are still energetic and are very likely to be translated into clinic in the near future.

Thermogravimetric analysis of bamboo-tar under different heating rates based on distributed activation energy model

Carbon fiber is a kind of new polymer material with excellent mechanical properties and being applied widely.The process of carbon fiber prepared by bamboo tar,including extraction,condensation,spinning,oxidation and carbonation,is influenced by the pyrolysis kinetics significantly.In this paper,the thermogravimetric analysis(TGA)of bamboo tar produced in the process of pyrolysis and gasification of the bamboo which is known as Phylostachys sulphurea,was analyzed by the distributed activation energy model(DAEM)to understand the kinetic properties and parameters of bamboo tar.The thermogravimetric analysis of bamboo tar which is used as the raw material of carbon fiber was conducted under 5 different heating rates(i.e.5,10,15,30 and 50℃/min,etc.)in nitrogen atmosphere.The results show that the activation energy of bamboo tar and the exponential factor increased significantly with the increase of the heating rate,and the low heating rate is advantageous to the extraction of bamboo tar solvent and the thermal polycondensation,which can provide scientific reference for the optimization of carbon fiber technology.The thermal weight results show that the temperature range of bamboo tar being decomposed rapidly is 213℃-410℃.The ranges of the activation energy were calculated by DAEM,which have small difference in comparisons with five heating rates when the conversion rate is at 0.1-0.6 and the average value of the activation energy is 119 kJ/mol.The stability range of the activation energy is enlarged when the conversion rate is greater than 0.6 and heating rate increases.