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A Cross-Sectional Study on the Impact of Operation Triple Zero (OTZ) Program on Viral Load Suppression amongst Members of the Adolescent Club in 68 Nigerian Army Reference Hospital Yaba Lagos, Nigeria
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作者 Nkechinyere Harrison Ismail Lawal +7 位作者 Yakubu Adamu Kehinde Aribisala Adegbenga Olarinoye Uzoamaka Agbaim Funmilayo Owolabi Dooshima Okonkwo Laura Chittenden Nathan Okeji 《World Journal of AIDS》 2024年第2期35-44,共10页
Background: In Nigeria, adolescents and young people (AYP) aged 10 - 24, comprise 22.3% of the population and with HIV prevalence of 3.5%. The AYP living with HIV enrolled at the 68 NARHY, Lagos reflects the national ... Background: In Nigeria, adolescents and young people (AYP) aged 10 - 24, comprise 22.3% of the population and with HIV prevalence of 3.5%. The AYP living with HIV enrolled at the 68 NARHY, Lagos reflects the national challenges with poor viral suppression. The OTZ program aligns with the UNAIDS 95-95-95 goals. It seeks to empower AYPLHIV to be in charge of their treatment and commit to triple zero outcomeszero missed appointments, zero missed drugs, and zero viral loads. The purpose of the study was to assess the impact of the OTZ program on viral load suppression among members of the adolescent club in 68 NARHY, Lagos. Method: A cross-sectional retrospective study to evaluate the impact of the OTZ program on the viral load of 53 AYP enrolled in the OTZ program between March 2019 to December 2019 was analyzed. The Percentage of viral load suppression before enrollment compared with 6 and 12 months after enrollment into the OTZ program. The AYP is grouped into 10 - 14, 15 - 19, and 20 - 24 years. Activities conducted were peer driven monthly meetings with the AYP during which the adolescents interacted on issues relating to improving their treatment outcomes, healthcare workers reviewed their clinical status, viral load result, provider peer counseling, and caregivers engagement to support adherence to medication and ARV refills. Results: Before OTZ, 81% aged 10 - 14 years, 75% aged 15 - 19 years, and 25% aged 20 - 24 years were virally suppressed (VL less than 1000 copies/ml). Six months after enrollment, 94% were virally suppressed95% aged 10 - 14 years, 96% aged 15 - 19 years, and 66% aged 20-24 years. Twelve months after enrollment, 96% of AYP were virally suppressed100% aged 10-14 years, 93% aged 15 - 19 years, and 100% aged 20 - 24 years. Males viral load (VL) suppression improved from 79% to 96% and 92%, while females VL suppression improved from 69% to 93% and 100% at 6 and 12 months respectively. Conclusion: The OTZ activities contributed to improved viral load suppression in the AYP of the facility. 展开更多
关键词 Impact Operation Triple zero ADOLESCENT Viral Load NIGERIA
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Two innovative equivalent statements of the third law of thermodynamics
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作者 陈晓航 周颖慧 陈金灿 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第6期324-328,共5页
It is found from textbooks and literature that there are three different statements for the third law of thermodynamics,i.e., the Nernst theorem, the unattainability statement of absolute zero temperature, and the hea... It is found from textbooks and literature that there are three different statements for the third law of thermodynamics,i.e., the Nernst theorem, the unattainability statement of absolute zero temperature, and the heat capacity statement. It is pointed out that such three statements correspond to three thermodynamic parameters, which are, respectively, the entropy,temperature, and heat capacity, and can be obtained by extrapolating the experimental results of different parameters at ultralow temperatures to absolute zero. It is expounded that because there is no need for additional assumptions in the derivation of the Nernst equation, the Nernst theorem should be renamed as the Nernst statement. Moreover, it is proved that both the Nernst statement and the heat capacity statement are mutually deducible and equivalent, while the unattainability of absolute zero temperature is only a corollary of the Nernst statement or the heat capacity statement so that it is unsuitably referred to as one statement of the third law of thermodynamics. The conclusion is that the Nernst statement and the heat capacity statement are two equivalent statements of the third law of thermodynamics. 展开更多
关键词 Nernst statement heat capacity statement Nernst theorem absolute zero temperature the third law of thermodynamics
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Research on Data Tampering Prevention Method for ATC Network Based on Zero Trust
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作者 Xiaoyan Zhu Ruchun Jia +1 位作者 Tingrui Zhang Song Yao 《Computers, Materials & Continua》 SCIE EI 2024年第3期4363-4377,共15页
The traditional air traffic control information sharing data has weak security characteristics of personal privacy data and poor effect,which is easy to leads to the problem that the data is usurped.Starting from the ... The traditional air traffic control information sharing data has weak security characteristics of personal privacy data and poor effect,which is easy to leads to the problem that the data is usurped.Starting from the application of the ATC(automatic train control)network,this paper focuses on the zero trust and zero trust access strategy and the tamper-proof method of information-sharing network data.Through the improvement of ATC’s zero trust physical layer authentication and network data distributed feature differentiation calculation,this paper reconstructs the personal privacy scope authentication structure and designs a tamper-proof method of ATC’s information sharing on the Internet.From the single management authority to the unified management of data units,the systematic algorithm improvement of shared network data tamper prevention method is realized,and RDTP(Reliable Data Transfer Protocol)is selected in the network data of information sharing resources to realize the effectiveness of tamper prevention of air traffic control data during transmission.The results show that this method can reasonably avoid the tampering of information sharing on the Internet,maintain the security factors of air traffic control information sharing on the Internet,and the Central Processing Unit(CPU)utilization rate is only 4.64%,which effectively increases the performance of air traffic control data comprehensive security protection system. 展开更多
关键词 zero trust access policy air traffic information sharing network privacy data tam-per-proof certification features
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Algorithm for Visualization of Zero Divisor Graphs of the Ring ℤn Using MAPLE Coding
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作者 Nasir Ali 《Open Journal of Discrete Mathematics》 2024年第1期1-8,共8页
This research investigates the comparative efficacy of generating zero divisor graphs (ZDGs) of the ring of integers ℤ<sub>n</sub> modulo n using MAPLE algorithm. Zero divisor graphs, pivotal in the study ... This research investigates the comparative efficacy of generating zero divisor graphs (ZDGs) of the ring of integers ℤ<sub>n</sub> modulo n using MAPLE algorithm. Zero divisor graphs, pivotal in the study of ring theory, depict relationships between elements of a ring that multiply to zero. The paper explores the development and implementation of algorithms in MAPLE for constructing these ZDGs. The comparative study aims to discern the strengths, limitations, and computational efficiency of different MAPLE algorithms for creating zero divisor graphs offering insights for mathematicians, researchers, and computational enthusiasts involved in ring theory and mathematical computations. 展开更多
关键词 zero Divisor Graph Ring Theory Maple Algorithm n Modulo n Graph Theory Mathematical Computing
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From Standard Policy-Based Zero Trust to Absolute Zero Trust (AZT): A Quantum Leap to Q-Day Security
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作者 Fazal Raheman 《Journal of Computer and Communications》 2024年第3期252-282,共31页
Cybercrime is projected to cost a whopping $23.8 Trillion by 2027. This is essentially because there’s no computer network that’s not vulnerable. Fool-proof cybersecurity of personal data in a connected computer is ... Cybercrime is projected to cost a whopping $23.8 Trillion by 2027. This is essentially because there’s no computer network that’s not vulnerable. Fool-proof cybersecurity of personal data in a connected computer is considered practically impossible. The advent of quantum computers (QC) will worsen cybersecurity. QC will be a boon for data-intensive industries by drastically reducing the computing time from years to minutes. But QC will render our current cryptography vulnerable to quantum attacks, breaking nearly all modern cryptographic systems. Before QCs with sufficient qubits arrive, we must be ready with quantum-safe strategies to protect our ICT infrastructures. Post-quantum cryptography (PQC) is being aggressively pursued worldwide as a defence from the potential Q-day threat. NIST (National Institute of Standards and Technology), in a rigorous process, tested 82 PQC schemes, 80 of which failed after the final round in 2022. Recently the remaining two PQCs were also cracked by a Swedish and a French team of cryptographers, placing NIST’s PQC standardization process in serious jeopardy. With all the NIST-evaluated PQCs failing, there’s an urgent need to explore alternate strategies. Although cybersecurity heavily relies on cryptography, recent evidence indicates that it can indeed transcend beyond encryption using Zero Vulnerability Computing (ZVC) technology. ZVC is an encryption-agnostic absolute zero trust (AZT) approach that can potentially render computers quantum resistant by banning all third-party permissions, a root cause of most vulnerabilities. Unachievable in legacy systems, AZT is pursued by an experienced consortium of European partners to build compact, solid-state devices that are robust, resilient, energy-efficient, and with zero attack surface, rendering them resistant to malware and future Q-Day threats. 展开更多
关键词 CYBERSECURITY Quantum Computers Post Quantum Cryptography Q-Day zero Trust
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虚拟桌面与零客户端在实验室管理中的研究应用——VMware Horizon View与Dell Wyse Zero Client的融合研究
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作者 吴磊 《佳木斯大学学报(自然科学版)》 CAS 2024年第1期125-128,共4页
我校计算机实验室至今仍在使用2006年开发的机房计费管理系统,此系统的刷卡终端安装于实验室外,常年运行在恶劣的户外环境中,因此故障频发,无法长时间正常运行。面对上述问题,我校教学环境部利用当前已趋于成熟的虚拟桌面技术,让机房计... 我校计算机实验室至今仍在使用2006年开发的机房计费管理系统,此系统的刷卡终端安装于实验室外,常年运行在恶劣的户外环境中,因此故障频发,无法长时间正常运行。面对上述问题,我校教学环境部利用当前已趋于成熟的虚拟桌面技术,让机房计费管理系统的刷卡终端能够稳定地运行在恶劣的户外环境中,并且能够便利地对其进行管理和维护。 展开更多
关键词 计算机实验室 刷卡终端 虚拟桌面 零客户端
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基于强化学习与Zero-DCE的图像增强方法
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作者 王鹏飞 单新文 +1 位作者 奚梦婷 魏晓龙 《电工技术》 2024年第1期47-51,共5页
在深度学习技术不断演进的背景下,图像增强技术在图像处理领域备受瞩目。尽管传统的处理方法在改善图像质量方面有所成就,但对于高动态范围、高噪声、低对比度等复杂场景的图像处理需求,其效果通常难以令人满意。采用了创新性的图像增... 在深度学习技术不断演进的背景下,图像增强技术在图像处理领域备受瞩目。尽管传统的处理方法在改善图像质量方面有所成就,但对于高动态范围、高噪声、低对比度等复杂场景的图像处理需求,其效果通常难以令人满意。采用了创新性的图像增强方法,将图像分解为照明和反射两部分,以实现更为出色的增强效果。综合运用Retinex、Zero-DCE和强化学习技术,提升了图像质量和可视性,在处理复杂场景中展现了显著的效果。通过强化学习和组合损失函数,使得图像增强效果更显著。基于Retinex理论的实现方式进一步加强了整体算法的性能。此外,结合Zero-DCE的方法,通过深度曲线估计照明和反射两部分,有效区分了不同场景的图像增强需求。 展开更多
关键词 强化学习 微光增强 zero-DCE RETINEX
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A deep‐sea sulfate‐reducing bacterium generates zero‐valent sulfur via metabolizing thiosulfate
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作者 Rui Liu Yeqi Shan +2 位作者 Shichuan Xi Xin Zhang Chaomin Sun 《mLife》 2022年第3期257-271,共15页
Zero‐valent sulfur(ZVS)is a crucial intermediate in the sulfur geobiochemical circulation and is widespread in deep‐sea cold seeps.Sulfur‐oxidizing bacteria are thought to be the major contributors to the formation... Zero‐valent sulfur(ZVS)is a crucial intermediate in the sulfur geobiochemical circulation and is widespread in deep‐sea cold seeps.Sulfur‐oxidizing bacteria are thought to be the major contributors to the formation of ZVS.However,ZVS production mediated by sulfate‐reducing bacteria(SRB)has rarely been reported.In this study,we isolated and cultured a typical SRB designated Oceanidesulfovibrio marinus CS1 from deep‐sea cold seep sediment in the South China Sea.We show that O.marinus CS1 forms ZVS in the medium supplemented with thiosulfate.Proteomic and protein activity assays revealed that thiosulfate reductase(PhsA)and the sulfide:quinone oxidoreductase(SQR)played key roles in driving ZVS formation in O.marinus CS1.During this process,thiosulfate firstly was reduced by PhsA to form sulfide,then sulfide was oxidized by SQR to produce ZVS.The expressions of PhsA and SQR were significantly upregulated when O.marinus CS1 was cultured in a deep‐sea cold seep,strongly indicating that strain CS1 might form ZVS in the deep‐sea environment.Notably,homologs of phsA and sqr were widely identified from microbes living in sediments of deep‐sea cold seep in the South China Sea by the metagenomic analysis.We thus propose that SRB containing phsA and sqr genes potentially contribute to the formation of ZVS in deep‐sea cold seep environments. 展开更多
关键词 cold seep in situ sulfate reducing bacteria sulfide oxidation zero‐valent sulfur
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Zero-P颈椎前路融合系统治疗双节段颈椎病的临床研究 被引量:1
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作者 张硕 刘正 +3 位作者 吴四军 贾俊秀 唐冲 汪文龙 《颈腰痛杂志》 2023年第2期193-196,共4页
目的探讨Zero-P颈椎前路融合系统治疗双节段颈椎病的临床疗效。方法选取2013年1月~2017年12月于本院因颈椎退行性疾病行双节段前路颈椎间盘切除椎间融合术的患者,应用传统椎间融合器+钉板固定系统者为A组,应用Zero-P融合器者为B组。对... 目的探讨Zero-P颈椎前路融合系统治疗双节段颈椎病的临床疗效。方法选取2013年1月~2017年12月于本院因颈椎退行性疾病行双节段前路颈椎间盘切除椎间融合术的患者,应用传统椎间融合器+钉板固定系统者为A组,应用Zero-P融合器者为B组。对两组患者的围手术期指标和术后疗效、并发症情况进行评价。结果A组患者手术时间显著长于B组(P<0.05),术后吞咽困难发生率显著高于B组(P<0.05)。与术前相比,两组患者术后3个月、12个月和末次随访时(>24个月)的JOA评分、NDI指数和VAS评分均显著改善(P<0.05),但组间差异无统计学意义(P>0.05)。两组术后各时间点的颈椎整体前凸角、颈椎间隙高度均较术前显著矫正(P<0.05);与术后3个月相比,上述指标在末次随访时的矫正程度有所丢失,但差异无统计学意义(P>0.05)。结论Zero-P手术治疗双节段颈椎病,可取得与传统钉板系统固定同样的手术效果,且手术时间短、吞咽困难发生率低。 展开更多
关键词 颈椎病 零切迹融合器 颈椎前路手术 椎间融合 吞咽困难
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Synthesis of clay-supported nanoscale zero-valent iron using green tea extract for the removal of phosphorus from aqueous solutions 被引量:6
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作者 Akbar Soliemanzadeh Majid Fekri 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2017年第7期924-930,共7页
This study addresses the synthesis of nanoscale zero-valent iron(n ZVI) in the presence of natural bentonite(B-n ZVI) using green tea extract. The natural bentonite and B-n ZVI were then applied for the removal of pho... This study addresses the synthesis of nanoscale zero-valent iron(n ZVI) in the presence of natural bentonite(B-n ZVI) using green tea extract. The natural bentonite and B-n ZVI were then applied for the removal of phosphorus from aqueous solutions at various concentrations, p H levels and contact time. The desorption of phosphorus(P) from adsorbents was done immediately after sorption at the maximum initial concentration using the successive dilution method. The characterization of FTIR, SEM, and XRD indicated that n ZVI was successfully loaded to the surface of natural bentonite. The sorption of phosphorus on B-n ZVI was observed to be p H-dependent, with maximum phosphorus removal occurring at the p H range of 2 to 5. The results demonstrate that the maximum sorption capacities of natural bentonite and B-n ZVI were 4.61 and 27.63 mg·g^(-1), respectively.Langmuir, Freundlich, and Redlich–Peterson models properly described the sorption isotherm data. For either adsorbent, desorption isotherms did not coincide with their corresponding sorption isotherms, suggesting the occurrence of irreversibility and hysteresis. The average percentages of retained phosphorus released from natural bentonite and B-n ZVI were 80% and 9%, respectively. The results indicated that sorption kinetics was best described by the pseudo-second-order model. The present study suggests that B-n ZVI could be used as a suitable adsorbent for the removal of phosphorus from aqueous solutions. 展开更多
关键词 绿茶提取物 零价铁 水溶液 除磷 纳米 合成 天然膨润土 吸附等温线
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Synthesis of nanoscale zero-valent iron supported on exfoliated graphite for removal of nitrate 被引量:10
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作者 张环 金朝晖 +1 位作者 韩璐 秦承华 《中国有色金属学会会刊:英文版》 CSCD 2006年第B01期345-349,共5页
Nano ZVI particles supported on micro-scale exfoliated graphite were prepared by using KBH4 as reducing agent in the H2O/ethanol system. The supported ZVI materials generally have higher activity and greater flexibili... Nano ZVI particles supported on micro-scale exfoliated graphite were prepared by using KBH4 as reducing agent in the H2O/ethanol system. The supported ZVI materials generally have higher activity and greater flexibility for environmental remediation applications. The exfoliated graphite as the support was treated beforehand to hydrophilic material. Nano iron particles are deposited onto the rough graphite surface while those were formed by borohydride reduction. The possible nitrate reduction pathways were proposed. The TEM image shows that iron particles are highly dispersed on the surface of graphite and several of iron particles are imbedded in the pit of support surface. In this synthesis, iron particles have a nearly spherical shape with a grain size of 50?100 nm. The surface areas of materials with different iron loadings of 3.5%, 7.0%, 10.0%, 15.0% and 20.0%(mass fraction) are 2.89, 9.55, 8.45, 23.8 and 6.18 m2·g?1 by BET surface analyzer. The chemical reduction of nitrate by supported nano ZVI in aqueous solution were tested in series batch experiments. Experiment results suggest that NO3? can be more rapidly reduced to NH4+ at neutral pH and anaerobic conditions by supported nano ZVI than unsupported nano ZVI or ZVI scraps. The 15% nano Fe/graphite shows the best reduction efficiency contrasted with other Fe loading particles. 展开更多
关键词 纳米级0价铁粒子 合成 片状剥落石墨 载体 硝酸盐脱除
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Advanced treatment of biologically pretreated coking wastewater by intensified zero-valent iron process(IZVI) combined with anaerobic filter and biological aerated filter(AF/BAF) 被引量:4
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作者 潘碌亭 韩悦 吴锦峰 《Journal of Central South University》 SCIE EI CAS CSCD 2015年第10期3781-3787,共7页
Experiments were conducted to investigate the behavior of the sequential system of intensified zero-valent iron process(IZVI) and anaerobic filter and biological aerated filter(AF/BAF) reactors for advanced treatment ... Experiments were conducted to investigate the behavior of the sequential system of intensified zero-valent iron process(IZVI) and anaerobic filter and biological aerated filter(AF/BAF) reactors for advanced treatment of biologically pretreated coking wastewater. Particular attention was paid to the performance of the integrated system for the removal of chemical oxygen demand(COD), ammonia nitrogen(NH3-N) and total nitrogen(TN). The average removal efficiencies of COD, NH3-N and TN were 76.28%, 96.76% and 59.97%, with the average effluent mass concentrations of 56, 0.53 and 18.83 mg/L, respectively, reaching the first grade of the national discharge standard. Moreover, the results of gas chromatography/mass spectrum(GC/MS) and gel permeation chromatography(GPC) analysis demonstrated that the refractory organic compounds with high relative molecular mass were partly removed in IZVI process by the function of oxidation-reduction, flocculation and adsorption which could also enhance the biodegradability of the system effluent. The removal efficiencies of NH3-N and TN were achieved mainly in the subsequent AF/BAF reactors by nitrification and denitrification. Overall, the results obtained show that the application of IZVI in combination with AF/BAF is a promising technology for advanced treatment of biologically pretreated coking wastewater. 展开更多
关键词 曝气生物滤池 焦化废水 深度处理 厌氧滤池 附加费 零价铁 生物预处理 燃油
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Treatment of simulated wastewater containing Reactive Red 195 by zero-valent iron/activated carbon combined with microwave discharge electrodeless lamp/sodium hypochlorite 被引量:6
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作者 Jie Fu Zhen Xu +4 位作者 Qing-Shan Li Song Chen Shu-Qing An Qing-Fu Zeng Hai-Liang Zhu 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2010年第4期512-518,共7页
A comparative study of treatment of simulated wastewater containing Reactive Red 195 using zero-valent iron/activated carbon (ZVI/AC), microwave discharge electrodeless lamp/sodium hypochlorite (MDEL/NaCIO) and th... A comparative study of treatment of simulated wastewater containing Reactive Red 195 using zero-valent iron/activated carbon (ZVI/AC), microwave discharge electrodeless lamp/sodium hypochlorite (MDEL/NaCIO) and the combination of ZVI/AC- MDEL/NaCIO was conducted. The preliminary results showed the two steps method of ZVI/AC-MDEL/NaCIO had much higher degradation efficiency than both single steps. The final color removal percentage was nearly up to 100% and the chemical oxygen demand reduction percentage was up to approximately 82%. The effects of operational parameters, including initial pH value of simulated wastewater, ZVI/AC ratio and particle size of ZVI were also investigated. In addition, from the discussion of synergistic effect between ZVI/AC and MEDL/NaCIO, we found that in the ZVI/AC-MEDL/NaCIO process, ZVI/AC could break the azo bond firstly and then MEDLfNaCIO degraded the aromatic amine products effectively. Reversing the order would reduce the degradation efficiency. 展开更多
关键词 activated carbon microwave discharge electrodeless lamp Reactive Red 195 sodium hypochlorite zero-valent iron.
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Dechlorination of trichloroethylene in solution over supported nano zero valent Fe and Cu/Fe bimetal on exfoliated graphite 被引量:1
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作者 Huan ZHANG Zhaohui JIN +2 位作者 Lu HAN Zongming XIU Chenghua QIN 《Chinese Journal Of Geochemistry》 EI CAS 2006年第B08期132-133,共2页
关键词 双金属材料 三氯乙烯 脱氯法 催化反应 溶液 石墨
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Sorption Kinetic of Arsenate as Water Contaminant on Zero Valent Iron 被引量:1
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作者 Osama Eljamal Keiko Sasaki Tsuyoshi Hirajima 《Journal of Water Resource and Protection》 2013年第6期563-567,共5页
This study investigates the sorption of arsenate from water using zero-valent iron ZVI as sorbent. Batch experiments were carried out to study the sorption kinetics of arsenate under different concentrations of arsena... This study investigates the sorption of arsenate from water using zero-valent iron ZVI as sorbent. Batch experiments were carried out to study the sorption kinetics of arsenate under different concentrations of arsenate varies from 0.5 to 200 mg/l. A kinetic model was considered to describe the arsenates sorption on ZVI material. The kinetics of the arsenate sorption processes were described by the Langmuir kinetic model. The sorption capacity increases with high initial concentration which obtained the maximum sorption 2.1 mg/g at 200 mg/l of arsenate initial concentration. The results show that the rapid initial sorption rates of arsenate were occurred at the beginning of experiments running time, followed by a slower removal that gradually approaches an equilibrium condition. The data from laboratory batch experiments were used to verify the simulation results of the kinetic model resulting in good agreement between measured and modeled results. The results indicate that ZVI could be employed as sorbent materials to enhance the sorption processes and increase the removal rate of arsenate from water. 展开更多
关键词 Arsenic SORPTION LANGMUIR KINETIC Model zero-valent IRON Removal of ARSENATE Iron(III)
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Degradation of nitrobenzene-containing wastewater by sequential nanoscale zero valent iron-persulfate process 被引量:2
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作者 Jingjuan Qiao Weizhou Jiao Youzhi Liu 《Green Energy & Environment》 SCIE CSCD 2021年第6期910-919,共10页
As nitrobenzene(NB)is structurally stable and difficult to degrade due to the presence of an electron withdrawing group(nitro group).The sequential nanoscale zero valent iron-persulfate(NZVI-Na_(2)S_(2)O_(8))process w... As nitrobenzene(NB)is structurally stable and difficult to degrade due to the presence of an electron withdrawing group(nitro group).The sequential nanoscale zero valent iron-persulfate(NZVI-Na_(2)S_(2)O_(8))process was proposed in this study for the degradation NB-containing wastewater.The results showed that the NB degradation efficiency and the total organic carbon removal efficiency in the sequential NZVINa_(2)S_(2)O_(8)process were 100%and 49.25%,respectively,at a NB concentration of 200 mg L^(-1),a NZVI concentration of 0.75 g L^(-1),a Na_(2)S_(2)O_(8)concentration of 26.8 mmol L^(-1),an initial pH of 5,and a reaction time of 30 min,which were higher than those(88.53%and 35.24%,respectively)obtained in the NZVI/Na_(2)S_(2)O_(8)process.Sulfate radicals(SO_(4)·-)and hydroxyl radicals(·OH)generated in the reaction were identified directly by electron paramagnetic resonance spectroscopy and indirectly by radical capture experiments,and it was shown that both SO_(4)^(·-)and·OH played a major role in the sequential NZVI-Na_(2)S_(2)O_(8)process.The possible pathways involved in the reduction of NB to aniline(AN)and the further oxidative degradation of AN were determined by gas chromatography-mass spectrometry. 展开更多
关键词 Nanoscale zero valent iron Impinging stream-rotating packed bed Sequential NZVI-Na2S2O8process NITROBENZENE Degradation pathways
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Enhanced degradation of carbon tetrachloride by surfactant-modified zero-valent iron
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作者 MENG Ya-feng GUAN Bao-hong WU Zhong-biao WANG Da-hui 《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 SCIE CAS CSCD 2006年第9期702-707,共6页
Sorption of carbon tetrachloride (CT) by zero-valent iron (ZVI) is the rate-limiting step in the degradation of CT, so the sorption capacity of ZVI is of great importance. This experiment was aimed at enhancing the so... Sorption of carbon tetrachloride (CT) by zero-valent iron (ZVI) is the rate-limiting step in the degradation of CT, so the sorption capacity of ZVI is of great importance. This experiment was aimed at enhancing the sorption of CT by ZVI and the degradation rate of CT by modification of surfactants. This study showed that ZVI modified by cationic surfactants has favorable synergistic effect on the degradation of CT. The CT degradation rate of ZVI modified by cetyl pyridinium bromide (CPB) was higher than that of the unmodified ZVI by 130%, and the CT degradation rate of ZVI modified by cetyl trimethyl ammonium bromide (CTAB) was higher than that of the unmodified ZVI by 81%. This study also showed that the best degradation effect is obtained at the near critical micelle concentrations (CMC) and that high loaded cationic surfactant does not have good synergistic effect on the degradation due to its hydrophilicity and the block in surface reduction sites. Furthermore degradation of CT by ZVI modified by nonionic surfactant has not positive effect on the degradation as the ionic surfactant and the ZVI modified by anionic surfactant has hardly any obvious effects on the degradation. 展开更多
关键词 增强退化 吸附作用 表面活性剂 增强效应 零价铁
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Remediation of Malathion Contaminated Soil Using Zero Valent Iron Nano-Particles
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作者 R. K. Singhal B. Gangadhar +3 位作者 H. Basu V. Manisha G.R. K. Naidu A.V. R. Reddy 《American Journal of Analytical Chemistry》 2012年第1期76-82,共7页
In this study, iron nano-particles were used to remediate malathion contaminated soil in the concentration range of 1 - 10 μg?g–1. The zero valent iron nano-particles were prepared by reducing ferric chloride soluti... In this study, iron nano-particles were used to remediate malathion contaminated soil in the concentration range of 1 - 10 μg?g–1. The zero valent iron nano-particles were prepared by reducing ferric chloride solution with sodium boro- hydride for remediation of the soil. The optimized quantity of iron nano particles was found to be 0.1 g?kg–1 of soil con- taminated with 10 μg?g–1 of malathion. Malathion was determined in the soil after leaching to water at pH 8.2 and fol- lowed by its oxidation with slight excess of N-bromosuccinimide (NBS). The unconsumed NBS was estimated by measuring the decrease in the color intensity of rhodamine B. Degradation product formed during the oxidation of ma-lathion by zero valent iron was monitored by the Attenuated Total Reflectance Fourier Transform Infrared Spectros- copy (ATR-FTIR). The results clearly showed that quantitative oxidation of malathion was achieved within eight min- utes after the addition of zero valent iron nano particles. 展开更多
关键词 MALATHION zero valent Iron Nano Particle Soil CONTAMINATION
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Evaluating Effectiveness and Permanence of Selenium Treatment in a Solid Matrix via Aqueous-Mediated Zero Valent Iron Reaction
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作者 Scott A. Grieco Danielle C. Singer Gary R. Bement 《Journal of Environmental Protection》 2017年第9期990-1001,共12页
Increasingly, as regulatory limits become more stringent, selenium has become a parameter of concern. Selenium is a naturally occurring element that is largely mobilized by anthropogenic activity such as mining for fu... Increasingly, as regulatory limits become more stringent, selenium has become a parameter of concern. Selenium is a naturally occurring element that is largely mobilized by anthropogenic activity such as mining for fuel and subsequent combustion, metal ore refining and processing, and agricultural irrigation. Of concern is removing selenium liquid matrices and immobilizing it from leachable solid matrices. Chemical reduction and stabilization using zero valent iron (ZVI) is applicable to both concerns. The solid matrix case study is applicable to ash ponds solids or industrial bag house dust solids. This paper presents data for treatment and stabilization of selenium within a solid matrix using ZVI. The methodology uses an aqueous mediate reaction to promote a stable solid matrix of non-leachable selenium. The paper describes matrix challenges and key variables that effected successful treatment. Testing with simulated and real bag house dust solids were used to establish data to support the permeance of the reaction. The data show that ZVI converts ionic selenium to a zero valent state in the solid matrix. It was also recognized that a fraction of ionic selenium may fail to react with the ZVI, but the results show that despite the presence of the unreacted ionic selenium, the toxicity characteristic leachate procedure (TCLP) results following treatment do not exceed the 1 mg/L hazardous waste criteria. 展开更多
关键词 BAG House Dust SELENIUM Chemical Reduction Land DISPOSAL Restrictions Toxicity Characteristic LEACHING Procedure TCLP zero valent Iron
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