Allium cepa root tip assay in assessment of toxicity of magnesium oxide nanoparticles and microparticles

Allium cepa bioassay had been used from decades for the assessment of toxicants and their harmful effects on environment as well as human health. Magnesium oxide(MgO) particles are being utilized in different fields. However, reports on the adverse effects of MgO nanoparticles on the environment and mankind are scarce. Hence, the toxicity of MgO particles is of concern because of their increased utilization. In the current study, A. cepa was used as an indicator to assess the toxicological efficiency of MgO nano-and microparticles(NPs and MPs) at a range of exposure concentrations(12.5, 25, 50, and100 μg/m L). The toxicity was evaluated by using various bioassays on A. cepa root tip cells such as comet assay, oxidative stress and their uptake/internalization profile. Results indicated a dose dependent increase in chromosomal aberrations and decrease in mitotic index(MI) when compared to control cells and the effect was more significant for NPs than MPs(at p 0.05). Comet analysis revealed that the Deoxyribonucleic acid(DNA) damage in terms of percent tail DNA ranged from 6.8–30.1 over 12.5–100 μg/m L concentrations of MgO NPs and was found to be significant at the exposed concentrations. A significant increase in generation of hydrogen peroxide and superoxide radicals was observed in accordance with the lipid peroxidation profile in both MgO NPs and MPs treated plants when compared with control. In conclusion, this investigation revealed that MgO NPs exposure exhibited greater toxicity on A. cepa than MPs.     

Influence of stabilizers on the antimicrobial properties of silver nanoparticles introduced into natural water

Physical, chemical and biochemical properties of silver nanoparticles(AgNPs) depend to a great extent on their size, shape, size distribution, and stabilizers located on their surface. This study focused on two typical stabilizers, namely citrates(cit), low molecular ions protecting nanoparticles by electrostatic repulsion, and polyvinylpyrrolidone(PVP), a hydrophilic, neutral, high molecular polymer protecting nanoparticles by steric stabilization. Natural bacterioplankton was collected from a eutrophic, downtown lake and exposed to five concentrations(0.1–5 mg/L) of AgNPs-PVP and AgNPs-cit. Responses were monitored after 1, 3, 5 and 7 days of exposure, by evaluating the survival rate of bacteria, their respiratory activity, and the general activity of extracellular esterases. A significantly better(greater) survival rate of bacterioplankton was observed in water with an addition of AgNPs-cit. The inhibition of extracellular esterases was observed only in samples containing AgNPs-PVP. The inhibitory effect increased proportionally to the concentration of AgNPs-PVP applied. Within the studied concentration range, there was no statistically significant inhibition of bacterioplankton respiratory activity by AgNPs-PVP and AgNPs-cit.     

纳米氧化锌、硫酸锌和AM真菌对玉米生长的影响

纳米氧化锌(Zn O)是应用最为广泛但具有一定生物毒性的金属型纳米颗粒(nanoparticles,NPs)之一,而丛枝菌根(arbuscular mycorrhizal,AM)真菌能改善宿主植物矿质营养和增强宿主植物抗逆性,但纳米Zn O和其他锌污染物之间的关系以及AM真菌对其生物效应的影响目前尚不清楚.通过温室盆栽试验,研究了单一或复合施加纳米Zn O、ZnSO_4(500mg·kg~(-1))时接种AM真菌Funneliformis mosseae BEG 167对玉米生长的影响.结果表明,纳米Zn O对AM真菌侵染和玉米植株生长有一定抑制作用,表现出植物毒性,且与同浓度(500 mg·kg~(-1))下的ZnSO_4作用类似.与非菌根对照相比,接种AM真菌降低了玉米植株的Zn含量或Zn吸收量,且在复合处理中对玉米生长表现出较好的促生作用.结果首次表明,纳米ZnO与ZnSO_4在生物毒性上存在复杂的交互作用,而接种AM真菌在二者复合污染时对玉米具有一定的保护作用.     

A mechanistic study of ciprofloxacin adsorption by goethite in the presence of silver and titanium dioxide nanoparticles

The adsorption behaviors of ciprofloxacin (CIP), a fluoroquinolone antibiotic, onto goethite (Gt) in the presence of silver and titanium dioxide nanoparticles (AgNPs and TiO₂NPs) were investigated. Results showed that CIP adsorption kinetics in Gt with or without NPs both followed the pseudo-second-order kinetic model. The presence of AgNPs or TiO₂NPs inhibited the adsorption of CIP by Gt. The amount of inhibition of CIP sorption due to AgNPs was decreased with an increase of solution pH from 5.0 to 9.0. In contrast, in the presence of TiO₂NPs, CIP adsorption by Gt was almost unchanged at pHs of 5.0∼6.5 but was decreased with an increase of pH from 6.5 to 9.0. The mechanisms of AgNPs and TiO₂NPs in inhibiting CIP adsorption by Gt were different, which was attributed to citrate coating of AgNPs resulting in competition with CIP for adsorption sites on Gt, while TiO₂NPs could compete with Gt for CIP adsorption. Additionally, CIP was adsorbed by Gt or TiO₂NPs through a tridentate complex involving the bidentate inner-sphere coordination of the deprotonated carboxylic group and hydrogen bonding through the adjacent carbonyl group on the quinoline ring. These findings advance our understanding of the environmental behavior and fate of fluoroquinolone antibiotics in the presence of NPs.     

不同环境条件下水铁矿和针铁矿纳米颗粒稳定性

纳米颗粒的团聚和分散是控制许多重要环境过程的关键因素.本研究通过测定水铁矿纳米颗粒(FHNPs)和针铁矿纳米颗粒(GTNPs)的粒径和Zeta电位,计算DLVO相互作用能,探究了不同pH、离子和有机质条件下两种纳米颗粒的稳定性.结果表明Na⁺和Ca²⁺通过离子强度的作用促进FHNPs和GTNPs团聚;低浓度PO₄^3-(2mmol·L^-1)、HA和FA(2 mg·L^-1和10 mg·L^-1)吸附在铁矿物纳米颗粒上,改变其表面电荷,提高FHNPs和GTNPs在中高pH条件下的稳定性.高浓度的PO₄^3-(10mmol·L^-1)虽然也可改变铁矿物纳米颗粒的电性,但由于离子强度的作用,对GTNPs的稳定性贡献不大.FHNPs或GTNPs的Zeta电位接近于0时,其相互作用的一级势垒和次级势阱常常同时不存在,两种纳米颗粒主要以不可逆的方式在一级势阱中团聚;当一级势垒和次级势阱同时存...     

基于聚合多巴胺的磁性碳材料的制备及其对甲基绿的吸附

以聚合多巴胺为碳源制备碳材料包覆的磁性纳米颗粒.通过多巴胺的自聚合反应将其包覆在Fe_3O_4纳米颗粒上,在氩气保护下高温灼烧得Fe_3O_4@C复合材料.包覆碳材料后,Fe_3O_4颗粒的稳定性和分散性提高.使用扫描电镜、透射电镜、红外光谱和振动磁强计对材料进行了表征.结果表明成功地制备了核壳结构的Fe_3O_4@C复合材料.用甲基绿来考察Fe_3O_4@C的吸附性能.研究表明,溶液pH对甲基绿的吸附有显著的影响,随溶液pH的升高,甲基绿的吸附容量显著增大.用朗格缪尔吸附等温模型拟合出在纯水、湖水和自来水中Fe_3O_4@C对甲基绿的最大吸附容量分别为490.1、442.5和389.1 mg·g~(-1).热力学研究计算出吸附的吉布斯自由能为负值,说明吸附是自发过程.动力学研究表明甲基绿在Fe_3O_4@C上的吸附过程符合拟二级反应动力学方程,吸附速率较快.     

纳米颗粒原位植入法制备改性超滤膜及其抗生物污染性能研究

选取氧化铝分散体(Al2O3)、Linde A型沸石(LTA)、Linde L型沸石(LTL)和X型八面沸石(FAU-X)4种纳米颗粒,采用原位植入的方法对超滤膜进行表面改性,以提高聚砜超滤膜的抗生物污染性能.通过扫描电子显微镜、接触角测定、抗生物污染性能测试等方法来表征改性前后膜结构和性能的变化.结果表明,纳米颗粒在膜表面的原位植入具有其可行性,该方法只改变超滤膜的表面形貌,对断面和底面的结构没有影响;纳米颗粒原位植入法改性后,超滤膜的亲水性有显著提高.就抗生物污染性能而言,纳米颗粒的植入提高了膜的抗粘附性能,在纳米颗粒覆盖的区域没有大肠杆菌粘附生长;在这4种膜中,UF-LTA和UF-LTL膜的抗粘附性能优于UF-Al2O3和UF-FAU-X膜.相较而言,LTA型沸石在膜表面分散效果良好,原位植入后显著改善了膜的亲水性并且表现出较好的抗粘附性能,可作为理想的材料用于下一步研究.但LTA型沸石的抗水流剪切的能力较弱,要想提高该种纳米颗粒在膜表面的结合牢固性,应考虑减小颗粒的粒径.     

小麦和水稻对纳米硒的吸收和转运

通过水培试验,研究了不同粒径纳米硒(Se NPs)和不同p H条件对小麦(Triticum aestivum L.)及水稻(Oryza sativa L.)吸收、转运硒的影响.结果表明,小麦和水稻对不同粒径(50、100和150 nm) Se NPs的吸收规律不同. 24 h和72 h处理下,小麦根系对3种粒径Se NPs的吸收无显著差异,但其地上部中的硒含量(以干重计,下同)在50 nm Se NPs处理下达到最高,分别为(1. 89±0. 47)μg·g-1和(5. 18±1. 51)μg·g-1.硒在小麦体内的转运系数也在50 nm Se NPs处理24 h时显著高于其他粒径Se NPs处理2. 38倍(P 0. 05).对于水稻而言,50 nm Se NPs处理24 h时根系中的硒含量分别比100 nm和150 nm Se NPs处理增加了11. 18%和41. 81%,但在72 h时3种粒径Se NPs处理间根系对硒的吸收无显著差异.同时,硒在水稻中的地上部含量和转运系数也在50 nm Se NPs处理达到了最大值.另外,p H条件也会影响植物对硒的吸收和转运. Se NPs处理24h时,小麦根系在p H为6时对硒的吸收量最大,并高于亚硒酸盐处理89. 47%,但在p H为4时小麦对硒的转运能力最强.水稻在p H较低时(p H为3. 5和5. 5),对Se NPs的吸收量显著低于亚硒酸盐,且Se NPs在p H为3. 5时更易转运.以上结果表明水稻和小麦均可以吸收Se NPs,并且在p H较低的环境下Se NPs粒径越小越容易在植物体内转运.     

不同pH条件下赤铁矿纳米粒子的聚集和再分散行为研究

纳米粒子的聚集和再分散行为是影响纳米粒子在环境中归趋的重要因素.选取赤铁矿纳米粒子作为研究对象,用Zeta电位和粒径测定仪系统研究其在不同pH条件下的聚集和再分散过程.结果表明,当pH在7.0～8.7之间时,赤铁矿纳米粒子发生较快的聚集(如当pH为8.2时平均粒径在400s内由31nm增加到1400nm).当pH≤6.3时,赤铁矿纳米粒子几乎不发生聚集.不经老化聚集的赤铁矿纳米粒子均能发生再分散,但是再分散过程并不完全可逆,而是呈现一定的非线性.老化使得更多的赤铁矿纳米粒子发生不可逆的聚集,在等电点处老化后的样品不发生再分散.当pH为7.0和8.9时,老化的样品再分散后的平均粒径(约500nm)大于不老化的样品(约250nm).纳米粒子聚集-再分散过程的非线性对预测其在环境中的存在状态和生态效应带来了大的困难.     

Green synthesis, characterization and antimicrobial activity of silver nanoparticles using methanolic root extracts of Diospyros sylvatica

The current research study focuses to formulate the biosynthesized silver nanoparticles for the first time from silver acetate using methanolic root extracts of Diospyros sylvatica, a member of family Ebenaceae. TEM analysis revealed the average diameter of Ag NPs around 8 nm which is in good agreement with the average crystallite size (10 nm) calculated from X-ray Diffraction (XRD) analysis. Further the study has been extended to the antimicrobial activity against test pathogenic Gram (+) ve, Gram (−) ve bacterial and fungal strains. The bioinspired Ag-NP showed promising activity against all the tested bacterial strains and the activity was enhanced with increased dosage levels.     

Effects of silica nanoparticles on growth and photosynthetic pigment contents of Scenedesmus obliquus

To assess the aquatic ecosystem safety for silica (SiO2) nanoparticles (NPs), the growth inhibition and photosynthetic pigment contents of Scenedesmus obliquus in logarithm growth phase exposed to SiO2 NPs and SiO2 bulk particles (BPs) suspensions were measured. SiO2 NPs with 10-20 nm diameters were found to be toxic. The 20% effective concentration (EC20) values for 72 and 96 hr were 388.1 and 216.5 mg/L, respectively. The contents of chlorophyll decreased significantly under moderate and high concentratio...     

Intracellular biosynthesis of Au and Ag nanoparticles using ethanolic extract of Brassica oleracea L. and studies on their physicochemical and biological properties

In this present study, we reported broccoli (Brassica oleracea L.) as a potential candidate for the synthesis of gold and silver nanoparticles (NPs) in green chemistry method. The synthesized metal nanoparticles are evaluated their antimicrobial efficacy against different human pathogenic organisms. The physico-chemical properties of gold nanoparticles were analyzed using different analytical techniques such as a UV-Vis spectrophotometer, Field Emission Scanning Electron Microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction and a Fourier Transform Infrared spectrophotometer. In addition, gold and silver NP antimicrobial efficacy was checked by disc diffusion assay. UV-Vis color intensity of the nanoparticles was shown at 540 and 450 nm for gold and silver nanoparticles respectively. Higher magnification of the Field Emission Scanning Electron Microscopy image shows the variable morphology of the gold nanoparticles such as spherical, rod and triangular shapes and silver nanoparticles were seen in spherical shapes. The average spherical size of the particles was observed in 24- 38 nm for gold and 30-45 nm for silver NPs. X-ray diffraction pattern confirmed the presence of gold nanoparticles and silver nanoparticles which were crystalline in nature. Additionally, the functionalmetabolites were identified by the Fourier TransformInfrared spectroscopy. IR spectra revealed phenols, alcohols, aldehydes (sugar moieties), vitamins and proteins are present in the broccoli extract which are accountable to synthesize the nanoparticles. The synthesized gold and silver NPs inhibited the growth of the tested bacterial and fungal pathogens at the concentration of 50 μg/mL respectively. In addition, broccoli mediated gold and silver nanoparticles have shown potent antimicrobial activity against human pathogens. © 2015 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences.     

Intracellular biosynthesis of Au and Ag nanoparticles using ethanolic extract of Brassica oleracea L. and studies on their physicochemical and biological properties

In this present study, we reported broccoli (Brassica oleracea L.) as a potential candidate for the synthesis of gold and silver nanoparticles (NPs) in green chemistry method. The synthesized metal nanoparticles are evaluated their antimicrobial efficacy against different human pathogenic organisms. The physico-chemical properties of gold nanoparticles were analyzed using different analytical techniques such as a UV–Vis spectrophotometer, Field Emission Scanning Electron Microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction and a Fourier Transform Infrared spectrophotometer. In addition, gold and silver NP antimicrobial efficacy was checked by disc diffusion assay. UV–Vis color intensity of the nanoparticles was shown at 540 and 450 nm for gold and silver nanoparticles respectively. Higher magnification of the Field Emission Scanning Electron Microscopy image shows the variable morphology of the gold nanoparticles such as spherical, rod and triangular shapes and silver nanoparticles were seen in spherical shapes. The average spherical size of the particles was observed in 24–38 nm for gold and 30–45 nm for silver NPs. X-ray diffraction pattern confirmed the presence of gold nanoparticles and silver nanoparticles which were crystalline in nature. Additionally, the functional metabolites were identified by the Fourier Transform Infrared spectroscopy. IR spectra revealed phenols, alcohols, aldehydes (sugar moieties), vitamins and proteins are present in the broccoli extract which are accountable to synthesize the nanoparticles. The synthesized gold and silver NPs inhibited the growth of the tested bacterial and fungal pathogens at the concentration of 50 μg/mL respectively. In addition, broccoli mediated gold and silver nanoparticles have shown potent antimicrobial activity against human pathogens.     

Comparative cytotoxicity of nanoparticles and ions to Escherichia coli in binary mixtures

The objective of this study was to understand toxicity of mixture of nanoparticles (NPs) (ZnO and TiO₂) and their ions to Escherichia coli. Results indicated the decrease in percentage growth of E. coli with the increase in concentration of NPs both in single and mixture setups. Even a small concentration of 1 mg/L was observed to be significantly toxic to E. coli in binary mixture setup (exposure concentration: 1 mg/L ZnO and 1 mg/L TiO₂; 21.15% decrease in plate count concentration with respect to control). Exposure of E. coli to mixture of NPs at 1000 mg/L (i.e., 1000 mg/L ZnO and 1000 mg/L TiO₂) resulted in 99.63% decrease in plate count concentration with respect to control. Toxic effects of ions to E. coli were found to be lesser than their corresponding NPs. The percentage growth reduction was found to be 36% for binary mixture of zinc and titanium ions at the highest concentration (i.e., 803.0 mg/L Zn and 593.3 mg/L Ti where ion concentrations are equal to the Zn ions present in 1000 mg/L ZnO NP solution and Ti^+ 4 ions present in 1000 mg/L TiO₂ NP solution). Nature of mixture toxicity of the two NPs to E. coli was found to be antagonistic. The alkaline phosphatase (Alp) assay indicated that the maximum damage was observed when E. coli was exposed to 1000 mg/L of mixture of NPs. This study tries to fill the knowledge gap on information of toxicity of mixture of NPs to bacteria which has not been reported earlier.     

纳米硒化银的生物合成及其对染料的吸附去除

利用菌株Pantoea sp.IMH实现了硒化银纳米颗粒的生物合成,同时,结合高分辨透射电镜(HRTEM)、能谱成像(EDX-mapping)、X射线粉末衍射(XRD)等多种表征手段对硒化银纳米颗粒进行了表征分析.结果表明,所合成的硒化银纳米颗粒的粒径为10~20 nm,其纳米颗粒的晶面间距为0.225 nm,对应于Ag2Se的(031)晶面.所合成的纳米颗粒的衍射环对应的标准Ag2Se晶面为(013)、(031)和(113)面.XRD结果表明,纳米颗粒的晶面为(111)、(112)和(004)晶面,说明菌株IMH能够合成纳米硒化银晶体.通过以不同电性的染料分子亚甲基蓝(阳性)、日落黄(阴性)、靛蓝(中性)作为目标分子进行吸附去除应用探索,发现硒化银纳米颗粒对阳性和中性染料分子有良好的吸附去除效果.这是由于硒化银纳米颗粒表面带有负电荷(Zeta电位分别为-11.8 m V(p H=5)、-13.0 m V(p H=7)、-13.0 m V(p H=9)).本研究为硒化银纳米颗粒的生物合成提供了新思路,拓展了硒化银纳米颗粒的合成方法.     

植物对纳米颗粒的吸收、转运及毒性效应

随着工程纳米颗粒的广泛使用,这些纳米材料不可避免地进入环境,对环境造成未知影响.植物是高等生物暴露于纳米颗粒的一条主要途径,工程纳米颗粒可能通过食物链使其在高营养水平生物中积累.植物与纳米颗粒间的相互作用应该受到关注和重视.已有的文献表明纳米颗粒能被植物选择性地吸收并引起植物毒性,但纳米颗粒进入植物体内的机制仍不明确.多数关于植物吸收纳米颗粒的研究是在理想条件如水培实验下开展,并且集中在植物的种子发芽或是幼苗生长阶段.描述纳米颗粒在植物体内的生物转化和在植物体内分配的报道较少,而且这方面的机制没有阐述清楚.目前有许多研究者关注纳米颗粒的植物毒性效应,但这方面的研究需要进一步深入.     

Evaluation of the adsorption potential of titanium dioxide nanoparticles for arsenic removal

The adsorption potential of titanium dioxide (TiO2) nanoparticles for removing arsenic from drinking water was evaluated. Pure and iron-doped TiO2 particles are synthesized via sol-gel method. The synthesized TiO2 nanoparticles were then immobilized on ordinary sand for adsorption studies. Adsorption isotherms were conducted on the synthesized nanoparticles as well as the sand coated with TiO2 nanoparticles under varying conditions of air and light, namely, the air-sunlight (A-SL), air-light (AL), air-dark (AD) and nitrogen-dark (ND). X-Ray diffraction (XRD) analysis showed that the pure and the iron-doped TiO2 nanoparticles were in 100% anatase crystalline phase with crystal sizes of 108 and 65 nm, respectively.Adsorption of arsenic on the three adsorbents was non-linear that could be described by the Freundlich and Langmuir adsorption models. Iron doping enhanced the adsorption capacity of TiO2 nanoparticle by arresting its grain growth and making it visible light responsive resulting in a higher affinity for arsenic. Similarly, the arsenic removal by adsorption on the sand coated with TiO2 nanoparticles was the highest among the three types of sand used. In all cases, As(V) adsorbed more compared with As(III). Solution pH appeared to be the most important factor in controlling the amount of arsenic adsorbed.     

长期暴露下纳米二氧化钛对典型淡水藻体砷累积与生物转化的影响

以铜绿微囊藻(Microcystis aeruginosa)和斜生栅藻(Scenedesmus obliquus)为研究对象,通过室内培养实验,研究了长期暴露下纳米二氧化钛(nano-TiO_2)对五价砷[As(Ⅴ)]在典型淡水藻体中累积与生物转化的影响.结果表明不同藻类对无机砷的吸收和转化能力差异很大.长期暴露下斜生栅藻累积的砷(As,以DW计,下同)高达(819.66±11.25)μg·g-1,比铜绿微囊藻累积的As[(355.95±8.31)μg·g-1]高2倍多.Nano-TiO_2可增加藻体对As的吸收累积,降低了培养基中As的含量.同时,nano-TiO_2可增加藻体对As(Ⅴ)的生化转化;其中,铜绿微囊藻中有机砷以二甲基砷(DMA)为主,而斜生栅藻中有机砷以一甲基砷(MMA)为主.另外,长期暴露下nano-TiO_2处理的铜绿微囊藻和斜生栅藻向培养基释放的甲基砷小于对照组,表明长期暴露中的nano-TiO_2不能促进藻体内甲基砷的释放.研究结果可促进nano-TiO_2与As相互作用时生态风险的理解.     

两种纳米颗粒对沸石吸附环丙沙星的影响

为了探明纳米颗粒（NPs）共存对抗生素在黏土矿物上的吸附的影响,以沸石为供试黏土矿物,环丙沙星（CIP）为目标污染物,研究了不同温度、 pH值和离子强度条件下,纳米氧化锌（ZnO NPs）和纳米二氧化钛（TiO₂ NPs）这2种NPs对沸石吸附CIP的影响,并结合沸石的表面特征探讨不同类型NPs对CIP吸附的影响机制.结果表明,除5 mg·L^-1ZnO NPs共存时,轻微促进了CIP的吸附,其他NPs浓度均对CIP产生不同程度的抑制,抑制程度表现出TiO₂ NPs>ZnO NPs的顺序;随温度升高,NPs的存在增强了沸石对CIP吸附的增温正效应;当离子强度由0.001mol·L^-1增加到0.01mol·L^-1时,CIP的吸附量下降,但2种NPs的存在均减弱了离子强度的负效应;溶液pH会影响CIP的存在形态和NPs的性质,进而影响CIP的吸附.沸石对单一CIP的吸附存在静电引力、氢键和孔径填充作用,ZnO NPs主要通过静电引力竞争吸附位点对CIP吸附产生影响,而TiO     

载银施氏矿物的制备及其对甲基橙的催化还原降解

采用硼氢化钠还原方法制备了不同载银量的银纳米粒子/施氏矿物复合催化剂（AgNPs/Sch）,利用扫描电镜（SEM）、X射线能谱（EDS）和X射线衍射（XRD）等测试方法对所制备催化剂的表面形貌、元素组成和物相组成进行了表征,证明了Ag成功负载于施氏矿物上.以甲基橙为目标污染物,硼氢化钠为还原剂,考察了不同载银量施氏矿物对甲基橙的催化降解性能,并探究了载银施氏矿物的投加量、硼氢化钠浓度、 甲基橙初始浓度、溶液初始pH等因素对甲基橙的催化还原降解效果的影响.结果表明,在甲基橙浓度为20 mg?L^-1、NaBH₄浓度为10 mmol?L^-1、初始pH=6条件下,反应90 min后,未载银的施氏矿物对甲基橙的降解率仅为7.5%,然而硝酸银添加量为0.10 g制备的AgNPs/Sch对甲基橙的降解率可达97.0%,该催化剂作为电子介质,能够将电子从还原剂（NaBH₄）转移到甲基橙中,进而加速甲基橙的降解.AgNPs/Sch在最佳的实验条件下5次循环性反应后,仍具有较高的催化稳定性.由此可见,载银施氏矿物作为一种新型的催化剂,在有机染料废水净化方面具有良好的应用前景.