Remediation of in-situ Leach Mining Contaminated Soil by Amendment-plant Synergism

This study aimed to remediate in-situ leach mining contaminated soil by amendment-plant synergism. The results showed that plant species exhibited ex-tremely significant effects on the concentration of nitrate nitrogen; to be specific, the concentration of nitrate nitrogen in soil planted with wheat was reduced from 692.19 mg/kg to lower than 100 mg/kg; when the mass ratio of amendment to soil reached 3：50 and the amendment particle size was 1-2 mm, the concentration of nitrate ni-trogen in soil planted with wheat was reduced to 43 mg/kg. The amendment type exhibited extremely significant effects on the concentration of ammonium nitrogen; to be specific, when the mass ratio of amendment to soil reached 10：50, the concen-tration of ammonium nitrogen in soil added with 2-3 mm zeolite was reduced from 23 593.75 to 3 300 mg/kg on day 15. Amendments and plants mainly exhibited desorption performance for sulfate radical in soil, and the amendment type extreme-ly significantly affected the concentration of sulfate radical; to be specific, the con-centration of sulfate radical in soil added with limestone increased from 370 mg/kg to 900 mg/kg on day 7.

Application research of enhanced in-situ micro-ecological remediation of petroleum contaminated soil

Experimental study of enhanced in-situ micro-ecological remediation of petroleum contaminated loess soil was carried out in Zhongyuan oil production areas, and the enhanced in-situ micro-ecological remediation technique includes optimistic in-situ microbial communities, physical chemistry methods, alfalfa planting and regulation of soil environmental elements. Experiments showed that the oil content in the contaminated soil with oil content about 2 898.25 mg/kg can be reduced about 98.61% after in-situ micro-ecological remediation for 99 days, which demonstrated the effectiveness of in-situ micro-ecological remediation methods for petroleum contaminated soil in central plains of China, and explored the practical and feasible application of these methods.

Mathematical Modei of In-situ Ozonation for the Remediation of 2-Chlorophenol Contaminated Soil

A microscopic diffusion-reaction modei was developed to simulate in-situ ozonation for the remediation of contaminated soil, i.e., to predict the temporal and spatial distribution of target contaminant in the subsurface. The sequential strategy was employed to obtain the numerical solution of the modei using finite difference method. A non-uniform grid of discretization points was emploved to increase the accuracy of the numerical solution by means of coordinate transformation. One-dimensional column tests were conducted to verify the modei. The column was packed with simulated soils that were spiked with 2-chlorophenol. Ozone gas passed through the column at a flow rate of 100ml·min-1. The residual 2-chlorophenol content at different depths of the column was determined at fixed time intervals. Compared the experimental data with the simulated values, it was found that the mathematical modei fitted data well during most time of the experiment.

In-situ remediation of deep petroleum-contaminated soil injection

A computational fluid dynamics(CFD)numerical simulation and field experiment were used to investigate optimal operating parameters of high-pressure jet grouting equipment and clarify the boundary law of the injection area in the remediation process.The response surface optimization design results show that the optimal injection pressure is 30 MPa,rotation speed is 23 r/min,commission speed is 30 cm/min,and the optimal injection diameter is 147.3 cm.Based on the CFD numerical simulation,the ratio of the injection core,turbulent zone,and seepage zone is approximately 1∶4∶2.The distribution law of jet core,turbulence zone and seepage zone at different cross-sections under 30 MPa operating conditions is as follows:The jet core radius is approximately 100 mm,the turbulence zone is mainly distributed at 100 to 500 mm,the seepage zone is mainly distributed at 500 to 700 mm,the seepage zone could be completed within 2 h,and the proportion of the three boundary zones in the injection zone is similar to that of the numerical simulation.This study provides theoretical parameters and practical reference for the remediation of deep pollution via in-situ chemical oxidation in the Loess Plateau soil environment.

Advances in Microbial Fuel Cells in the Field of Environmental Remediation

In order to protect ecological environment,it is urgent to restore the polluted environment. Among traditional methods of environmental remediation,it is common to add excessive electron donors or electron acceptors to the polluted environment,but these methods have a high cost and can cause secondary pollution easily. Microbial fuel cells( MFCs) can realize the transformation of pollutants and collection of electric energy by using microorganisms as a catalyst; they are clean,efficient and controlled easily and have a wide range of application,so MFCs have wide application prospects in the field of environmental remediation. In this study,MFCs and their applications in the field of environmental remediation were summarized.

A full-scale field experiment to study the thermal-deformation process of widening highway embankments in permafrost regions

As one of the widely used upgrading way in road engineering, the widening embankment(WE) has suffered evident differential deformation, which is even severer for highway in permafrost regions due to the temperature sensitivity of frozen soil and the heat absorption effect of the asphalt pavement. Given this issue, a full-scale experimental highway of WE was performed along the Qinghai-Tibet Highway(QTH) to investigate the differential deformation features and its developing law. The continuous three years' monitoring data taken from the experimental site, including the ground temperature and the layered deformation of WE and original embankment(OE), were used to analyze the thermal-deformation process. The results indicate that the widening part presented the remarkable thermal disturbance to the existing embankment(EE). The underlying permafrost was in a noteworthy degradation state, embodying the apparent decrease of the permafrost table and the increase of the ground temperature. Correspondingly, the heat disruption induced by widening led to a much higher deformation at the widening side compared to the original embankment, showing a periodic stepwise curve. Specifically, the deformation mainly occurred in the junction of the EE and the widening part, most of which was caused by the thawing consolidation near the original permafrost table. In contrast, the deformation of EE mainly attributed to the compression of the active layer. Furthermore, it was the deformation origination differences that resulted in the differential deformation of WE developed gradually during the monitoring period, the maximum of which reached up to 64 mm.

In-situ electrochemical study on the eff ects of Fe(Ⅲ)on kinetics of pyrite acidic pressure oxidation

Fe(Ⅲ)has been proved to be a more eff ective oxidant than dissolved oxygen at ambient temperature,however,the role of Fe(Ⅲ)in pyrite acidic pressure oxidation was rarely discussed so far.In this paper,in-situ electrochemical investigation was performed using a flow-through autoclave system in acidic pressure oxidation environment.The results illustrated that increasing Fe(Ⅲ)concentrations led to raising in redox potential of the solution,and decreased passivation of pyrite caused by deposition of elemental sulfur.Reduction of Fe(Ⅲ)at pyrite surface was a fast reaction with low activation energy,it was only slightly promoted by rising temperatures.While,the oxidation rate of pyrite at all investigated Fe(Ⅲ)concentrations increased obviously with rising temperatures,the anodic reaction was the rate-limiting step in the overall reaction.Activation energy of pyrite oxidation decreased from 47.74 to 28.79 kJ/mol when Fe(Ⅲ)concentration was increased from 0.05 to 0.50 g/L,showing that the reaction kinetics were limited by the rate of electrochemical reaction at low Fe(Ⅲ)concentrations,while,it gradually turned to be diffusion control with increasing Fe(Ⅲ)concentrations.

Assessment of recoverable oil and gas resources by in-situ conversion of shale——Case study of extracting the Chang 7_(3) shale in the Ordos Basin

The purpose of this study is to investigate the entire evolution process of shales with various total organic contents(TOC)in order to build models for quantitative evaluation of oil and gas yields and establish methods for assessing recoverable oil and gas resources from in-situ conversion of organic matters in shale.Thermal simulation experiments under in-situ conversion conditions were conducted on Chang 7_(3) shales from the Ordos Basin in a semi-open system with large capacity.The results showed that TOC and R_(o) were the key factors affecting the in-situ transformation potential of shale.The remaining oil and gas yields increased linearly with TOC but inconsistently with R_(o).R_(o) ranged 0.75%—1.25%and 1.05%—2.3%,respectively,corresponding to the main oil generation stage and gas generation stage of shale in-situ transformation.Thus a model to evaluate the remaining oil/gas yield with TOC and R_(o) was obtained.The TOC of shale suitable for in-situ conversion should be greater than 6%,whereas its R_(o) should be less than 1.0%.Shales with 0.75%(R_(o))could obtain the best economic benefit.The results provided a theoretical basis and evaluation methodology for predicting the hydrocarbon resources from in-situ conversion of shale and for the identification of the optimum“sweet spots”.The assessment of the Chang 7_(3) shale in the Ordos Basin indicated that the recoverable oil and gas resources from in-situ conversion of organic matters in shale are substantial,with oil and gas resources reaching approximately 450×10^(8) t and 30×10^(12)m^(3),respectively,from an area of 4.27×10^(4) km^(2).

Thermal and saline tolerance of Antarctic krill Euphausia superba under controlled in-situ aquarium conditions

As a key species of the Southern Ocean ecosystem,the thermal and saline tolerances of Antarctic krill(Euphausia superb a Dana)are relatively unknown because of the challenging environment and complicated situations needed for observation have inhibited in-situ experiments in the field.Hence,the thermal and saline tolerance of krill were examined under in-situ aquarium conditions with different controlled scenarios.According to the experiments,the critical lethal times of krill were 24h,2h and 0.5h under 9℃,12℃,and 15℃,respectively,and the estimated 50%lethal times were about 17.1 h and 1.7 h under 12℃and 15℃,respectively.Additionally,the critical lethal times(the estimated 50%lethal times)of krill were approximately 14h and 0.5h(about 22.9 h and 1.7 h)of salinity under 19.7 and 15.9,respectively.The observed critical and 50%lethal times of krill were 0.5 h and approximately 1.4 h,respectively,salinity under 55.2.The critical and 50%lethal temperatures of krill were 13℃and approximately 14.2℃,respectively.Additionally,the critical and 50%lethal salinity was 19.6 and approximately 17.5 for the lower saline(below normal oceanic salinity[34.4])environment and 50.3 and approximately 53.2 for the higher saline(above 34.4)environment,respectively.The upper thermal and saline preferences of krill can be considered 6℃and 26.8 to 41.2,respectively.These results can provide potential scenarios for predicting the possible fate of this key species in the Southern Ocean.

Microbial remediation of a pentachloronitrobenzene-contaminated soil under Panax notoginseng: A field experiment

Pentachloronitrobenzene(PCNB)is an organochlorine fungicide that is mainly used in the prevention and control of diseases in crop seedlings.Microbial removal is used as a promising method for in-situ removal of many organic pesticides and pesticide residues.A short-term field experiment(1 year)was conducted to explore the potential role of a PCNB-degrading bacterial isolate,Cupriavidus sp.YNS-85,in the remediation of a PCNB-contaminated soil on which Panax notoginseng was grown.The following three treatments were used:i)control soil amended with wheat bran but without YNS-85,ii)soil with 0.15 kg m-2of solid bacterial inoculum(A),and iii)soil with 0.30 kg m-2of solid bacterial inoculum(B).The removal of soil PCNB during the microbial remediation was monitored using gas chromatography.Soil catalase and fluorescein diacetate(FDA)esterase activities were determined using spectrophotometry.In addition,cultivable bacteria,fungi,and actinomycetes were counted by plating serial dilutions,and the microbial biodiversity of the soil was analyzed using BIOLOG.After 1 year of in-situ remediation,the soil PCNB concentrations decreased significantly by 50.3%and 74.2%in treatments A and B,respectively,when compared with the uninoculated control.The soil catalase activity decreased in the presence of the bacterial isolate,the FDA esterase activity decreased in treatment A,but increased in treatment B.No significant changes in plant biomass,diversity of the soil microbial community,or physicochemical properties of the soil were observed between the control and inoculated groups(P<0.05).The results indicate that Cupriavidus sp.YNS-85 is a potential candidate for the remediation of PCNB-contaminated soils under P.notoginseng.

Improved Methods for In-situ Measurement Railway Noise Barrier Insertion Loss

Many countries which seek to understand the acoustic performance of railway noise barriers have established standards for the conduct of in-situ experiments.However,there are no universally acknowledged receiver positions for the evaluation of the barrier performance,a fact which may be leading to uncertainty over the noise reduction capabilities of available barriers.In terms of the descriptor of the barrier performance,the general recommendation is the A-weighted sound pressure level,although the latter is considered to underestimate low frequencies for railway noise barrier.Thus,in this study,the comparison of receiver positions and the descriptors among existing Chinese,ISO and European standards were investigated.Based upon a combination of diffraction theory and standards,a rearrangement of receiver positions and one-third-octave-band analysis were proposed.In addition,in line with improved methods,an in-situ measurement of insertion loss for a 1.5 mhigh railway noise barrier was designed and conducted.The results of the experiment validate as effective and applicable the new receiver positions.These results also suggest that one-third-octave-band analysis is indispensable.

科教融合化学综合设计实验——纳米氧化亚铜制备及在染料废水修复中的应用

为契合国家节能减排的政策,开发设计了一个综合设计实验。学生首先制备纳米氧化亚铜,继而将产物用于模拟染料废水的修复,并探究不同实验条件对降解效果的影响。实验将基本实验技能、常见仪器使用与前沿科技相结合,涉及纳米材料制备、氧化降解技术、水体修复等概念,融合综合性、探究性、趣味性。教学方法借鉴科研模式,激发学生自主探究,有效培养低年级本科生的科研思维和创新能力,提高社会责任感。

Research progress and mechanism of nanomaterials-mediated in-situ remediation of cadmium-contaminated soil:A critical review

Cadmium contamination of soil is a global issue and in-situ remediation technology as a promising mitigation strategy has attracted more and more attention.Many nanomaterials have been applied for the in-situ remediation of cadmium-contaminated soil due to their excellent properties of the nano-scale size effect.In this work,recent research progress of various nanomaterials,including carbon nanomaterials,metal-based nanomaterials and nano mineral materials,in the removal of cadmium and in-situ remediation of cadmiumcontaminated soil were systematically discussed.Additional emphases were particularly laid on both laboratory and field restoration effects.Moreover,the factors which can affect the stability of cadmium,main interaction mechanisms between nanomaterials and cadmium in the soil,and potential future research direction were also provided.Therefore,it is believed that this work will ultimately contribute to the myriad of environmental cleanup advances,and further improve human health and sustainable development.

不同钝化剂对铅镉重金属污染土壤的修复影响研究

为研究不同种类钝化剂对铅、镉重金属污染土壤的修复效果影响,选择某化工厂铅、镉污染比较严重的黄壤作为修复对象,采用单一的无机钝化剂、生物炭类钝化剂、矿物钝化剂和有机-无机混合钝化剂对土壤进行修复。在不同类型钝化剂下,设计三因素三水平正交实验,除了钝化剂类型之外,所有条件都相似,研究上述各个类型钝化剂对土壤中铅、镉含量的钝化效率影响。研究结果表明,实验中所选择的生物炭、石灰、含硫型土壤调理剂、硅藻土按照一定比例混合而成的矿物钝化剂,对受试土壤中重金属铅、镉的钝化效果最好;通过正交实验结果可知,在矿物钝化剂使用量为460kg·hm^(-2)、土壤水分为50%、土壤粒径>2mm的情况下,能够获得最佳的铅、镉钝化效果,钝化效率分别为79.85%和87.18%。

“新农科”背景下本科生创新能力训练——以“土壤中邻苯二甲酸酯降解微生物鉴定实验”为例

“新农科”建设和科技快速发展对本科生的创新能力和实践能力提出了更高要求。为提升农业资源与环境专业本科生的实践创新能力,增强专业自信,本文详细阐述了农田土壤中广泛存在的污染物邻苯二甲酸酯降解微生物原位鉴定方法的优化过程,并将其成功应用于蔬菜基地土壤中邻苯二甲酸二(2-乙基己基)酯降解微生物研究。学生在开展创新训练过程中巩固了多学科理论知识,掌握了相关实验仪器操作和数据分析技能,熟悉了开展科学研究的基本流程,认识到科学前沿与农业生产实践的紧密联系,增强了专业自信和投身“三农”工作的责任感。在该创新实验的基础上已有本科生获得多项大学生创新创业项目资助。

服务补救视角下酒店顾客的心理契约重建研究

酒店行业高效的服务补救不仅可以消解顾客的负面情绪,还有助于提升顾客满意度,从而建立良好的客企关系。基于此,文章基于服务补救和恢复体验构建顾客满意度与心理契约重建的研究框架,通过对316份问卷进行PLS-SEM分析,获取了酒店服务补救下顾客心理契约的重建机制。研究表明:一是服务补救能够直接促进酒店顾客心理契约的形成;二是服务补救会通过恢复体验促使心理契约重建;三是服务补救能够提升顾客满意度进而实现心理契约的重建;四是服务补救通过恢复体验和顾客满意度的共同作用推动心理契约再形成。最后,从服务补救、恢复体验以及顾客满意度方面提出了针对顾客心理契约重建的对策建议,以期为酒店业的服务优化提供理论和实践支持。

氧化通风法在石油污染土壤修复中的实验验证

针对石油污染土壤修复,分别设置氧化实验和氧化通风实验,对使用对二甲苯模拟石油污染的实验土样进行污染物去除。分别选取臭氧浓度、含水率和污染物浓度作为氧化实验的影响因素,选取污染物浓度、通风流量、通风温度、通风时间和含水率作为氧化通风实验的影响因素。氧化实验的结果中,臭氧浓度对对二甲苯去除率影响最大,去除效果最好的实验数据为臭氧浓度100ppm、含水率5%、对二甲苯浓度2 000 mg/kg,去除率达到了78.47%。氧化通风实验的结果显示,通风温度对对二甲苯去除率影响最大,去除效果最好的实验数据为污染物浓度800 mg/kg、通风流量20 L/min、通风温度200℃、通风时间60 min、含水率5%,去除率达到了98.15%。由结果可知,氧化通风法对石油污染的土壤修复效果显著。

基于微纳米气泡修复技术的地下水重金属污染实验

结合微纳米气泡修复技术,对重金属污染进行有效处理,对实验结果进行记录与分析,结果表明,Cu^(2+)、Fe^(2+)、Pb^(2+)、Zn^(2+)四种重金属离子处理最适宜的环境分别为:Cu^(2+)处理环境:pH值为8.5、初始浓度为3 mg/L;Fe^(2+)处理环境:pH值为8.5、初始浓度为3.5 mg/L;Pb^(2+)处理环境:pH值为8、初始浓度为3.5 mg/L;Zn^(2+)处理环境:pH值为9、初始浓度为2.5 mg/L。此结果可为地下水重金属污染有效处理提供一定的理论支持。

不同修复模式对轻度砷污染农田修复效果的比较分析

为探讨不同修复模式对轻度砷污染农田的修复效果,2021年6—11月利用田间小区试验开展轻度砷污染农田修复效果研究。种植萝卜、茄子、甘蓝、空心菜4种农作物,选用原位钝化技术、农艺调控措施和深耕3种常用的农田修复技术,进行了26组不同修复技术方案的试验。结果表明:在26组修复技术方案中,最优推荐的农田修复方案有5组,分别为:(1)“叶面肥+甘蓝”组农作物中砷含量去除率高达84.6%;(2)“深耕+植空心菜”组土壤中有效砷含量去除率达94.6%;(3)“叶面肥+植萝卜”组农作物中砷含量去除率高达70.6%;(4)“土壤修复剂+叶面肥+甘蓝”组土壤中总砷含量去除率达23.2%;(5)“鸡粪+空心菜”组土壤中有效砷含量去除率达29.3%。研究表明,单一修复模式更适用于轻度砷污染的农田修复,其具有操作简单、修复费用低和修复效果好等优点,可为大面积开展轻度砷污染农田修复提供示范样板和技术方案。

高浓度多环芳烃污染土壤的微生物-植物联合修复技术研究

[目的]本文旨在研究多环芳烃(PAHs)污染场地微生物-植物联合修复PAHs污染土壤的效果。[方法]利用紫花苜蓿与PAHs降解菌株Rhizobium petrolearium SL-1联合修复土壤中PAHs,设置4个处理:不种苜蓿,不接根瘤菌(CK);不种苜蓿,接根瘤菌(菌);种苜蓿,不接根瘤菌(苜蓿);种苜蓿,接根瘤菌(苜蓿+菌),每个处理设3个重复。盆栽试验土壤取自山东新泰某焦化厂PAHs实地污染土壤,分别于处理20和60 d定期取样;大田试验农田位于河北省唐山市某发电厂附近,分别于处理60和90 d定期取样。测定苜蓿的株高和干质量等生理指标,并利用GC/MS分析土样中的16种PAHs组分降解规律。[结果]盆栽试验中,"苜蓿+菌"处理20和60 d时的苜蓿株高和干质量指标均优于仅种植苜蓿处理;"苜蓿+菌"联合降解PAHs效果明显优于只种植苜蓿或只接菌处理;PAHs不同组分间的降解效果从大到小依次为3环、2环、4环、6环、5环。在大田试验中,60和90 d修复效果同样呈现"苜蓿+菌"联合降解PAHs效果大于只种植苜蓿或只接菌的处理。修复60 d后土壤中低环PAHs的降解率明显高于高环PAHs,PAHs降解效果从大到小依次为2环、3环、4环、5环、6环,但修复90 d后土壤中低环PAHs和高环PAHs的降解率无明显差异。[结论]在PAHs污染土壤或大田试验条件下接种菌株SL-1对紫花苜蓿具有明显的促生作用,并且微生物-植物联合修复比单独微生物或植物修复能更有效地降解PAHs。