Titanium nanoparticles attenuates arsenic toxicity by up-regulating expressions of defensive genes in Vigna radiata L

Arsenic(As)-toxicity is recognized as one of the major environmental problems,affecting productivity of crops worldwide,thereby threatening sustainable agriculture and food security.Progression in nanotechnology and its impacts have brought up concerns about the application of engineered nanoparticles(NPs) in various sectors of the economy,including the field of agronomy.Among various NPs,there has been a rising amount of interest regarding the effects of titanium NPs(TiNPs) on plants growth and development,and their fate of abiotic stress tolerance.Hence,the present study was aimed to assess the ameliorative potentialities of chemically and biologically/green synthesized TiNPs to alleviate As-induced toxic responses in Vigna radiata L.The results revealed that exposure to As hindered the growth indices(radicle length and biomass) and membrane integrity,while were improved with the application of chemical and green synthesized TiNPs.In addition,treatment of As provoked the accretion of reactive oxygen species(superoxide and hydrogen peroxide) and malondialdehyde(a lipid per oxidized product),but were diminished by the supplementation of chemical and green manufactured TiNPs.The experimental data also signified that exogenous application of chemical and green synthesized TiNPs conferred tolerance to As-induced oxidative injuries via perking-up the expressions of antioxidant genes and enzyme systems viz;superoxide dismutase and catalase.Therefore,the present study inferred that chemically and green synthesized TiNPs,particularly green manufactured,effectively mitigated the adverse impacts of As by augmenting antioxidant machinery,thereby proving its potentiality in the alleviation of As-toxicity,at least in Vignaradiata L.     

Y型分子筛负载铁催化剂对活性艳蓝KN-R脱色的研究

利用Y型分子筛负载铁催化剂对活性艳蓝KN-R的脱色进行研究,探讨了催化剂的制备方法、铁负载量、投加剂量、反应体系pH值以及焙烧温度对活性艳蓝KN-R催化脱色效率的影响,并考察了催化剂的重复利用性能.结果表明:离子交换法制得的Y型分子筛负载铁催化剂表现出较佳的染料脱色性能.在pH＜3.0,H2O2投加剂量为50.0 mmol·l-1,催化剂投加剂量为4.0g·l-1的条件下,对初始浓度为250mg·l-1的KN-R模拟染料废水,30 min之内脱色率达95%以上.采用有机酸络合铁作为铁源制得的Y型分子筛负载铁催化剂的催化活性大幅增强,但催化剂稳定性降低.铁负载量影响染料的脱色反应活性,过量负载会导致染料脱色效率降低;同样,适度增大催化剂用量可促进染料脱色效率,但过量投加不利于染料的脱色.pH＜3.0为该Y型分子筛负载铁催化剂的适用pH条件;催化剂重复利用三次后,1h内对活性艳蓝KN-R的脱色率仍可达95%以上.     

Preparation of nZVI embedded modified mesoporous carbon for catalytic persulfate to degradation of reactive black 5

• The MCNZVI is prepared as an interesting material for PS activation. • Graphitized carbon shells facilitate electron transfer from Fe⁰. • The MCNZVI exhibits excellent performance to degrade RB5 by ¹O₂. • The MCNZVI has high stability and reusability in the oxidation system. High-efficiency and cost-effective catalysts with available strategies for persulfate (PS) activation are critical for the complete mineralization of organic contaminants in the environmental remediation and protection fields. A nanoscale zero-valent iron-embedded modified mesoporous carbon (MCNZVI) with a core-shell structure is synthesized using the hydrothermal synthesis method and high-temperature pyrolysis. The results showed that nZVI could be impregnated within mesoporous carbon frameworks with a comparatively high graphitization degree, rich nitrogen doping content, and a large surface area and pore volume. This material was used as a persulfate activator for the oxidation removal of Reactive Black 5 (RB5). The effects of the material dosage, PS concentration, pH, and some inorganic anions (i.e., Cl⁻, SO₄²⁻) on RB5 degradation were then investigated. The highest degradation efficiency (97.3%) of RB5 was achieved via PS (20 mmol/L) activation by the MCNZVI (0.5 g/L). The pseudo-first-order kinetics (k = 2.11 × 10⁻² min⁻¹) in the MCNZVI/PS (0.5 g/L, 20 mmol/L) was greater than 100 times than that in the MCNZVI and PS. The reactive oxygen species (ROS), including ¹O₂, SO₄^·−, HO^·, and ·O₂⁻, were generated by PS activation with the MCNZVI. Singlet oxygen was demonstrated to be the primary ROS responsible for the RB5 degradation. The MCNZVI could be reused and regenerated for recycling. This work provides new insights into PS activation to remove organic contamination.     

零价铁与过硫酸盐异相芬顿降解活性艳橙X-GN

采用零价铁(Fe~0)与过硫酸盐构建异相类芬顿体系,由Fe0腐蚀释放Fe~(2+)催化S_2 O_8~(2-)产生硫酸根自由基快速降解偶氮染料活性艳橙,考察了初始p H值、Fe~0投加量、过硫酸盐投加量和温度对降解过程的影响。结果表明,当活性艳橙初始浓度为100 mg/L、pH值为7、Fe~0投加量为0.5 g/L、过硫酸盐投加量为1 mmol/L和反应温度为30℃时,反应60 min后活性艳橙降解率达到92.6%。酸性条件和提高反应温度均有利反应的进行,而且活性艳橙的降解率在初始pH值为9时也高于90%。反应过程符合准一级动力学,表观反应速率常数k为0.0513 min~(-1)(30℃)。UV-Vis扫描显示,活性艳橙的发色基团在反应过程中被破坏。由Fe~0与S_2O_8~(2-)构成的异相Fenton体系可作为一种高效手段用于染料废水的处理。     

耐盐菌GTY对偶氮染料活性艳红X-3B的脱色研究

为了选择耐盐菌GTY对偶氮染料活性艳红X-3B的最佳脱色条件,研究了不同环境条件对脱色效果的影响,结果表明耐盐菌GTY对偶氮染料活性艳红X-3B有较好的脱色效果,能够适应较宽范围的pH值以及污染物负荷,当pH值在7～9之间,活性艳红X-3B初始浓度在600mg/L以下,GTY菌液生长期在对数末期时脱色效果达到最佳状态,24h脱色率能达到90%左右。同时考察了GTY的不同初始接菌量对活性艳红X-3B脱色的影响,结果发现高的初始接菌量可以提高脱色速率,但是一定时间后,初始接菌量对最终脱色效果并无太大影响,兼顾节约成本和脱色效果选择最佳初始接菌量为5%。     

纳米ZnO光催化剂的制备及性能研究

以Zn(CH3COO)2·H2O和NH4HCO3为原料,以室温固相反应和微波辐射技术相耦合的方法制备出粒径在19nm左右的ZnO光催化剂,同时以活性艳兰KN-R为模拟染料废水考察了所制备纳米ZnO的光催化性能。结果表明,所制备纳米ZnO具有良好的光催化活性,在适宜的操作条件下,活性艳兰KN-R的脱色率在96%以上,COD的去除率在69%以上。此外,在染料的浓度为30～100mg/L时,ZnO/UV体系光催化降解活性艳兰KN-R符合一级反应动力学模型。     

玄武湖蓝藻水华应急治理成效分析

2005年9-10月间，以粘土法为主，对玄武湖蓝藻水华进行了应急治理。经监测表明，应急治理有效抑制了蓝藻水华，湖区景观明显改善。形成蓝藻水华的微囊藻，各湖区下降幅度大于95％。综合污染指数、富营养化程度均有不同程度的降低，水体透明度提高0．14m，水质化学耗氧量、高锰酸盐指数、总磷浓度大幅降低，但生态补水主要流经区域pH无明显改善，各湖区总氮超标率有所上升。浮游植物数量下降93％，浮游动物种群数量上升47％，底栖动物种类数量无显著变化。相对静止水域细菌总数持平，生态补水流经区域细菌总数下降幅度较大。治理期间未发现大型水生植物、鱼虾批量死亡。沉积物中，铜、铅、砷含量无明显差异，汞含量升高，但低于往年监测水平，有机质略有升高，总磷含量有较大幅度上升。