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To reduce the leaching potential, to prevent groundwater contamination and to maintain the efficacy of a pesticide, natural polysaccharides have received increasing attention due to their biocompatibility and useful biological reactivity for controlled release formulations (CRFs) of pesticides. In this paper, the toxicities of the chiral herbicide dichlorprop (DCPP) and its complexes with chitosan molecules (DCPP-CS) and chitosan nanoparticles (DCPP-NP) to two different green algae were determined and compared. The inhibition rates of DCPP, DCPP-CS and DCPP-NP were determined at 24, 48, 72, 96, 120, 144, 168 h, and the results show that (S)-DCPP was more toxic to Chlorella vulgaris than (R)-DCPP, while the (R)-DCPP was more toxic to Scenedesmus obliquus than (S)-DCPP. The study also found that the chiral selectivity of DCPP to Chlorella vulgaris and Scenedesmus obliquus could be changed when DCPP was complexed with chitosan molecules (CS) or chitosan nanoparticles (NP). For Chlorella vulgaris, the order of inhibition was (R)-DCPP-CS > (S)-DCPP-CS and (R)-DCPP-NP > (S)-DCPP-NP; for Scenedesmus obliquus, the order was (S)-DCPP-CS > (R)-DCPP-CS and (S)-DCPP-NP > (R)-DCPP-NP. This phenomenon suggests that the enantioselective behaviors of chiral compounds might shift when interactions with other chiral receptors coexist in different biological environments. Additionally, chitosan molecules and chitosan nanoparticles also showed different toxicities, which could be ascribed to the difference in the physicochemical properties between CS and NP or the differences in the cell walls of the two fresh water green algae. 相似文献
195.
活性硅酸聚合硫酸铁的研究 总被引:12,自引:0,他引:12
以硅酸钠,硫酸和聚合硫酸铁为原料制备活性硅酸合硫酸铁,测定了ASPFS红外光谱,了Fe/Si摩尔比和水样PH值等因素对产品和除浊效果的影响当Fe/Si摩尔比为1.5时产品稳定性和除浊效果均较好。 相似文献
196.
对臭氧氧化去除焦化废水生化出水COD的反应动力学及其影响因素进行了实验研究,结果表明,在臭氧投加量为8.50 mg/min,反应温度为20℃和初始pH为10.61条件下,对COD的降解符合表观一级反应动力学模型,其相关系数R2=0.9991,表观反应速率常数kAbs=1.01×10-3 s-1。该条件下,臭氧氧化对COD的降解主要来源于高活性羟基自由基的强氧化作用。在不同的臭氧投加量(4.25~12.75 mg/min)、不同的反应温度(10~40℃)和不同的初始pH(3.76~12.53)下,COD的降解也同样遵循一级反应动力学规律。随着臭氧投加量的增大,COD降解的表观反应速率常数从(0.554×10-3) s-1增加到(1.06×10-3) s-1;随着反应温度的升高,表观反应速率常数从(0.427×10-3) s-1增加到(1.40×10-3) s-1,温度越高反应速率提高的幅度却越小;在初始pH3.76~10.61范围内,表观反应速率常数从(0.218×10-3) s-1增加到(1.01×10-3) s-1,在初始pH为12.53时表观反应速率常数下降到(0.857×10-3) s-1。 相似文献
197.
酶法降解偶氮染料刚果红是一个复杂的过程,受温度、pH、酶量、刚果红浓度和双氧水浓度显著影响。为研究各因素及因素间交互作用对刚果红降解影响,提高刚果红的降解率,分别使用单因素法和响应面分析法对刚果红降解条件进行了优化。单因素实验结果显示灰盖鬼伞过氧化物酶降解刚果红的最适条件为:pH 5.0、32℃、酶量4.98 U、双氧水0.1 mmol/L、刚果红20 mg/L,此时刚果红最高降解率为34.84%。然后选双氧水浓度、刚果红浓度和灰盖鬼伞过氧化物酶量作为3个因素,通过中心组合设计实验,用响应面法对刚果红降解进行优化分析,最后得到一个拟合度良好的二次多项方程模型(R2=0.9900)。方差分析结果显示,刚果红浓度和酶量是影响最显著的因素,双氧水与酶以及染料与酶之间的交互作用极显著。响应面分析优化后的反应体系为:双氧水浓度0.15 mmol/L,刚果红浓度为27.21 mg/L,酶为2.0 7 U,在此条件下,刚果红降解率达58.13%。 相似文献
198.
为了提高传统污水处理工艺的脱氮除磷效率、实现污泥资源化,本实验通过超声破解污泥获取碳源,采用耗氧呼吸速率分析上清液作为碳源的可行性,并将上清液回用于生活污水,考察其对A2O工艺长期运行的脱氮除磷效果和微生物群落结构的影响。结果表明,上清液中可降解有机物达到76.2%,具有作为内碳源的潜能;上清液和生活污水按1∶15投入A2O反应器后,氮、磷的去除率分别从63.2%和53.4%提高到了82.1%和94.7%;上清液明显改变了微生物群落结构,使除磷菌Actinobacteia和反硝化聚磷菌Sphingobacterium富集。 相似文献
199.
Yi-Hsiu Jen Wei-Hsiang Chen Chung-Shin Yuan Iau-Ren Ie Chung-Hsuang Hung 《Environmental science and pollution research international》2014,21(8):5474-5483
This study investigated the tempospatial variation of atmospheric mercury and its gas-particulate partition in the vicinity of a semiconductor manufacturing complex, where a plenty of flat-monitor manufacturing plants using elemental mercury as a light-initiating medium to produce backlight fluorescence tubes and may fugitively emit mercury-containing air pollutants to the atmosphere. Atmospheric mercury speciation, concentration, and the partition of total gaseous mercury (TGM) and particulate mercury (Hgp) were measured at four sites surrounding the semiconductor manufacturing intensive district/complex. One-year field measurement showed that the seasonal averaged concentrations of TGM and Hgp were in the range of 3.30–6.89 and 0.06–0.14 ng/m3, respectively, whereas the highest 24-h TGM and Hgp concentrations were 10.33 and 0.26 ng/m3, respectively. Atmospheric mercury apportioned as 92.59–99.01 % TGM and 0.99–7.41 % Hgp. As a whole, the highest and lowest concentrations of TGM were observed in the winter and summer sampling periods, respectively, whereas the concentration of Hgp did not vary much seasonally. The highest TGM concentrations were always observed at the downwind sites, indicating that the semiconductor manufacturing complex was a hot spot of mercury emission source, which caused severe atmospheric mercury contamination over the investigation region. 相似文献
200.
Yuan Sui Samir Droby Danfeng Zhang Wenjie Wang Yongsheng Liu 《Environmental science and pollution research international》2014,21(24):13956-13963
Significant losses in harvested fruit can be directly attributable to decay fungi and quality deterioration. Hot water treatment (HWT) has been demonstrated to be an effective and economic environment-friendly approach for managing postharvest decay and maintaining fruit quality. In this study, the effects of HWT (45 °C for 10, 15, 20, and 25 min) on in vitro growth of Fusarium oxysporum, in vivo Fusarium rot, and natural decay of melon were investigated. HWT inhibited spore germination and germ tube elongation of F. oxysporum. Protein impairment and ATP consumption triggered by HWT contributed to the inhibitory effect. Results of in vivo studies showed that HWT effectively controlled Fusarium rot and natural decay of melon. Correspondingly, HWT induced a significant increase in content of total phenolic compounds and lignin of melon. These findings indicate that the effects of HWT on Fusarium rot may be associated with the direct fungal inhibition and the elicitation of defense responses in fruit. Importantly, HWT used in this study had beneficial effects on fruit quality as well. HWT may represent an effective non-chemical approach for management of postharvest Fusarium rot. 相似文献