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991.
病原微生物所引发的传染性疾病严重威胁人类健康和生命。传统抗菌技术通常需要外加光、热等能量,如紫外线、光催化、微波等,实际应用受限。常温催化作为一种新型抗菌技术,能够在常温条件下发生催化氧化反应,产生强氧化性的活性氧物种而起杀菌作用。因此,常温催化技术在抗菌领域具有应用优势,综述其抗菌研究现状对于系统性认知常温催化抗菌具有指导意义。本文阐述了常温催化抗菌材料及其活性氧物种产生过程,介绍了常温催化抗菌性能的评价方法,讨论了常温催化抗菌的作用机制,重点分析了常温催化抗菌性能的影响因素。此外,基于国内外常温催化的抗菌研究现状,指出了常温催化抗菌研究存在的问题及未来发展趋势。 相似文献
992.
天然沸石负载La2O3-ZnO-TiO2光催化降解活性艳红K-2BP 总被引:1,自引:1,他引:0
利用80目天然斜发沸石作载体制备La2O3(0.5%)-ZnO(20%)-TiO2/沸石复合光催化剂,以20 W紫外灯为光源,在自制的光催化反应器中降解活性艳红K-2BP,考察了光照时间、空气通入量、催化剂用量、溶液初始浓度、H2O2与Fe3+投加量等对活性艳红K-2BP光催化降解率的影响。结果表明,当溶液初始浓度为60 mg/L,催化剂投加量为12 g/L,通气量为1 200 mL/min,光照2.5 h,活性艳红K-2BP的降解率可达99.2%;H2O2和Fe3+投加量为4 mL/L和3 g/L时,光照1 h活性艳红K-2BP降解率分别为100%和97.2%。紫外可见吸收光谱显示,LZTZ光催化剂可有效降解印染废水。 相似文献
993.
Cornelis A.M. van Gestel Josée E. Koolhaas Maarten van Hoppe Cora Korsman 《Environmental pollution (Barking, Essex : 1987)》2009,157(3):895-903
Effects on earthworms in the contaminated floodplain area the Biesbosch, the Netherlands, were determined at different levels of organization using a combination of field and laboratory tests. The species Lumbricus rubellus, collected from different polluted sites in the Biesbosch, showed reduced values for the biomarker neutral red retention time (NRRT), mainly explained by high metal concentrations in the soil and the resulting high internal copper concentrations in the earthworms. Organic pollutant levels in earthworms were low and did not explain reduced NRRTs. Earthworm abundance and biomass were not correlated with pollutant levels in the soil. Litterbag decomposition and bait-lamina feeding activity, measures of the functional role of earthworms, were not affected by metal pollution and did not show any correlation with metal concentrations in soil or earthworms nor with NRRT. Effects at the biochemical level therefore did not result in a reduced functioning of earthworm communities. 相似文献
994.
Background, aim, and scope Dye pollutants are a major class of environmental contaminants. Over 100,000 dyes have been synthesized worldwide and more
than 700,000 tons are produced annually and over 5% are discharged into aquatic environments. The adsorption or sorption is
one of the most efficient methods to remove dye and heavy metal pollutants from wastewater. However, most of the present sorbents
often bear some disadvantages, e.g. low sorption capacity, difficult separation of spoil, complex reproduction, or secondary
pollution. Development of novel sorbents that can overcome these limitations is desirable.
Materials and methods On the basis of the chemical coprecipitation of calcium oxalate (CaC2O4), bromopyrogallol red (BPR) was embedded during the growing of CaC2O4 particles. The ternary C2O4
2––BPR–Ca2+ sorbent was yielded by the centrifugation. Its composition was determined by spectrophotometry and AAS, and its structure
and morphology were characterized by powder X-ray diffraction (XRD), laser particle-size analysis, and scanning electron microscopy
(SEM). The adsorption of ethyl violet (EV) and heavy metals, e.g. Cu(II), Cd(II), Ni(II), Zn(II), and Pb(II) were carried
out and their removal rate determined by spectrophotometry and ICP-OES. The adsorption performance of the sorbent was compared
with powder activated carbon. The Langmuir isothermal model was applied to fit the embedment of BPR and adsorption of EV.
Results The saturation number of BPR binding to CaC2O4 reached 0.0105 mol/mol and the adsorption constant of the complex was 4.70 × 105 M–1. Over 80% of the sorbent particles are between 0.7 and 1.02 μm, formed by the aggregation of the global CaC2O4/BPR inclusion grains of 30–50 nm size. Such a material was found to adsorb cationic dyes selectively and sensitively. Ethyl
violet (EV) was used to investigate the adsorption mechanism of the material. One BPR molecule may just bind with one EV molecule.
The CaC2O4/BPR inclusion material adsorbed EV over two times more efficiently than the activated carbon. The adsorption of EV on the
CaC2O4/BPR inclusion sorbent was complete in only 5 min and the sedimentation complete in 1 h. However, those of EV onto activated
carbon took more than 1.5 and 5 h, respectively. The treatment of methylene blue and malachite green dye wastewaters indicated
that only 0.4% of the sorbent adsorbed over 80% of color substances. Besides, the material can also adsorb heavy metals by
complexation with BPR. Over 90% of Pb2+, and approximately 50% of Cd2+ and Cu2+, were removed in a high Zn2+-electroplating wastewater when 3% of the material was added. Eighty-six percent of Cu2+, and 60% of Ni2+ and Cd2+, were removed in a high Cd2+-electroplating wastewater.
Discussion The embedment of BPR into CaC2O4 particles responded to the Langmuir isothermal adsorption. As the affinity ligand of Ca2+, BPR with sulfonic groups may be adsorbed into the temporary electric double layer during the growing of CaC2O4 particles. Immediately, C2O4
2– captured the Ca2+ to form the CaC2O4 outer enclosed sphere. Thus, BPR may be released and embedded as a sandwich between CaC2O4 layers. The adsorption of EV on the sorbent obeyed the Langmuir isothermal equation and adsorption is mainly due to the ion-pair
attraction between EV and BPR. Different from the inclusion sorbent, the activated carbon depended on the specific surface
area to adsorb organic substances. Therefore, the adsorption capacity, equilibrium, and sedimentation time of the sorbent
are much better than activated carbon. The interaction of heavy metals with the inclusion sorbent responded to their coordination.
Conclusions By characterizing the C2O4
2––BPR–Ca2+ inclusion material using various modern instruments, the ternary in situ embedment particle, [(CaC2O4)95(BPR)]
n
2n–, an electronegative, micron-sized adsorbent was synthesized. It is selective, rapid, and highly effective for adsorbing cationic
dyes and heavy metals. Moreover, the adsorption is hardly subject to the impact of electrolytes.
Recommendations and perspectives The present work provides a simple and valuable method for preparing the highly effective adsorbent. If a concentrated BPR
wastewater was reused as the inclusion reactant, the sorbent will be low cost. By selecting the inclusion ligand with a special
structure, we may prepare some particular functional materials to recover the valuable substances from seriously polluted
wastewaters. The recommended method will play a significant role in development of advanced adsorption materials.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
995.
仿生矿化法制备壳聚糖/纳米CdS复合粒子对猩红B光催化降解研究 总被引:2,自引:1,他引:1
用仿生矿化法制备了壳聚糖/纳米CdS复合粒子,并用于可见光光催化降解猩红B染料模拟废水,系统地研究了染料初始浓度、pH值、催化剂投加量、光照情况和催化剂重复使用等因素对猩红B的光解脱色效率的影响。结果表明,当pH=3.0,催化剂投加量为0.7 g/L的条件下,对初始溶液为20 mg/L的猩红B模拟废水,60 min之内脱色率超过96%。酸性媒介比碱性媒介更有利于猩红B染料光解脱色。实验范围内Br-、NO-3和Cl-等无机阴离子,均对降解脱色有促进作用,其中NO3-对脱色作用促进最显著。处理前后的UV-Vis谱图分析表明猩红B在壳聚糖/纳米CdS复合粒子可见光光解处理过程中脱色是因为染料发生氧化光降作用。催化剂重复利用5次后,处理60 min对猩红B的脱色率仍可达到80.7%。 相似文献
996.
997.
铝业碱性赤泥的悬浮碳化法脱碱工艺研究 总被引:2,自引:0,他引:2
研究探讨了碱性废弃物赤泥的常压悬浮碳化法脱碱绿色环保新工艺。详细研究考察了反应温度、反应时间、液固比以及CO2通气量4个因素对赤泥脱碱效能的影响,确定了最佳工艺参数和技术条件。研究表明,在温控60℃,反应时间1.5 h,液固比为10,CO2通气量为0.8 L/min的反应条件下,赤泥脱碱率(以Na2O计)达到85%以上,同时得到含3%~5%碳酸盐的碱性溶液。与传统生石灰脱碱工艺相比,悬浮碳化法具有操作简便、脱碱率高、所得碱纯度高,无废弃物排放等优点,并可实现双废物(CO2废气和赤泥废弃物)的可持续综合利用。 相似文献
998.
999.
Investigation of potential interferences on the measurement of dissolved reactive phosphate using zirconium oxide-based DGT technique 总被引:1,自引:0,他引:1
A diffusive gradients in thin films (DGT) technique based on hydrous zirconium oxide (Zr-oxide) has been recently developed for the measurement of dissolved reactive phosphate (DRP). In this study, the detailed performance of the DGT technique is reported. Spiking experiments revealed that several orthophosphate monoester compounds contributed to the Zr-oxide DGT measurements of DRP. However, such a phenomenon is unlikely to occur during field conditions due to the low concentration of organic P in typical natural waters. The presence of Cl- (up to 106 g/L), SO42- (up to 16 g/L), HCO3- (up to 817 g/L), and AsO2- and AsO 3 4 (both up to 1 mg As/L) in solutions had negligible effects on the measurement of DRP. The threshold concentrations of Cl-, SO42- and HCO3- have been increased from previous reports for the measurements of DRP using other adsorbent-based DGT techniques. The capacity for DGT measurements of DRP decreased with increasing solution pH (4.2-9.2). The lowest capacity (95 μg P/m2 at pH 9.2) was still greater than that of other DGT techniques that are usually used for the measurement of DRP (2-12 μg P/cm2 ). The Zr-oxide binding gel could be stored for up to 2 years without any aging effect. This period of validity was considerably longer than the ferrihydrite binding gel that is commonly used in present DGT devices (6 months). The field application revealed that the concentrations of DRP measured in three fresh water samples using the Zr-oxide DGT technique were in agreement with those of the traditional colorimetric method. 相似文献
1000.
为揭示邻苯二甲酸二丁酯(dibutyl phthalate,DBP)对短裸甲藻(Gymnodinium breve)的抑制机制,采用荧光探针法和比色法研究了DBP对短裸甲藻活性氧(reactive oxygen species,ROS)、羟自由基.OH和过氧化氢H2O2含量以及超氧阴离子自由基O.2-产生速率的影响,同时观察了电子传递链抑制剂对DBP诱导ROS能力的影响.结果表明DBP诱导了短裸甲藻ROS的积累.随浓度的增大,DBP促进了.OH、H2O2的积累,如3 mg.L-1的DBP处理组,培养至48 h时.OH出现一个极大峰值33U.mL-1,约为对照组的2.4倍;H2 O2含量培养至72 h出现最大值,约为250 nmol.(107 cells)-1,约为对照组的5倍;但是DBP对O.2-产生速率的影响并没有显示出规律性.电子传递链选择性抑制实验表明DBP可能影响了藻细胞线粒体和细胞膜2个位点上电子传递,使.OH、H2O2含量和O.2-产生速率受到了不同的影响,最终诱导了短裸甲藻总ROS的积累.可见,DBP导致ROS的过量积累是其抑制藻细胞生长的主要机制.本研究结果对揭示化感物质抑制藻类的机制提供了科学依据. 相似文献