1.Introduction

Textile printing and dyeing industry,as an indispensable part of traditional industry,are going through the high-speed development period with the rapid economic development.What comes with this situation is the wastewater from underground or rivers with high content of toxic organic molecules.Thus,in the past two decades,the treatment of wastewater and creation of a better water environment have been research focuses[1–3].Towards this end,many researchers have attempted to use photocatalytic oxidation technology[4,5].Titanium dioxide(TiO2)nanoparticle is a promising heterogeneous photocatalysts.Due to its advantages of nontoxicity,low-cost and high photocatalytic activity,TiO2 has attracted considerable attention in the field of wastewater treatment and organic pollutants degradation[6–8].However,in practical application,the poor adsorption capacity of pure TiO2 seriously impeded its efficiency in the degradation of organic molecules[9].To solve this problem,current researches mainly focus on attaching TiO2 to organic/inorganic materials with high adsorption capacity[10–13].The obtained TiO2-based photocatalytic materials can enrich the organic molecules,and thus improve the efficiency of photocatalytic degradation of these molecules by TiO2.

Silica supports such as MCM-41,SBA-15,SBA-16 and hollow silica are ideal candidates for carrier material owing to its high specific surface area and chemical stability[14,15].In the past few years,a lot of works of combination of TiO2 and silica frameworks to form a catalytic material were reported[16–18].For example,Kevan and coworkers incorporated TiO2 into SBA-15 via incipient-wetness impregnation with titanium isopropoxide in ethanol followed by calcinations[19].They demonstrated that TiO2 existed as a thin film anchored inside the mesopores of SBA-15 and the obtained material could be used as photocatalysts for the degradation of organic contaminants.Hassan et al.reported a novel TiO2@MCM-41 nanocomposite which showed outstanding catalysts for the photocatalytic degradation of methylene blue[20].In fact,numbers of similar studies have demonstrated that the silica supported TiO2 could present better photocatalytic performance than traditional materials.

Recently,hierarchical wrinkled mesoporous silica materials(WMS),a new member of silica frameworks family,have attracted considerable attention in the field of carrier material[21].Compared with traditional MCMs and SBAs with ordered and monomodal mesopores,WMSs present hierarchical pore structures and radially oriented open pores,which endow this material with highly accessible active sites and adjustable mass transport paths[22].Very recently,our group successfully loaded silver nanoparticles on WMSs via an in situ chemical reduction approach, and demonstrated its durable and excellent antibacterial performance[23].Inspired by this,herein,we attempt to incorporate TiO2 into WMSs via anchoring titanium precursor with the highly dispersed functional groups on WMSs.Two advantages are expected in this new material.First,the hierarchical pore structure of WMSs is in favor of loading and stabilizing TiO2.Second,the radially oriented open pores of WMSs can significantly enhance the adsorption capacity of this material to organic molecules,which further improve its photocatalytic degradation efficiency.

2.Materials and methods

2.1.Materials

Cetyltrimethylammonium bromide (CTAB, AR, 99.0%), tetraethoxysilane(TEOS,AR,28%),(3-mercaptopropyl)trimethoxysilane(MPS),maleic anhydride,Rhodamine B(RhB)and all the solvents were purchased from Sinopharm Chemical Reagent Company.Cetylpyridinium bromide(CPB),butyl titanate and 3-aminopropyltriethoxysilane (APTES) were supplied by Aladdin Industrial Corporation.All the materials were used without any further purification

在武汉市5月上旬播种EK2S，播始历期80 d。据2017年8月中旬观察，EK2S在正常晴好天气下，每日 9：00—12：00 开花量占全日开花量 64.4%，花时高峰在 10：00—11：00，柱头外露率 74.6%，其中双边外露率 32.6%，持续张颖时间 81.2 min，包颈粒率 15.1%。 同期抽穗的广占 63S，每日 9：00—12：00开花量占全日开花量57.3%，花时高峰在11：00—12：00，柱头外露率 50.4%，其中双边外露率 30.0%，持续张颖时间 49.2 min，包颈粒率 24.4%。

[45]张贤明：《从本土诉求到全球视野：当代中国政治学繁荣与发展的思考》，《贵州社会科学》2012年第3期。

教师培训者是教师的“教师”。从个人视角出发，教师培训者的结构优化，包括培训者队伍来源类型优化和培训者自身素质优化。群体性知识或公共知识和教师个体性知识是教师知识的两个重要来源，教师培训者的队伍构成对应就应包含教育科学理论知识丰富的高校专家和一线教育教学经验丰富的中小学教师。教师培训者还应提升自身素质，如掌握和熟练应用隐性和显性知识的相互转化策略，教师个人知识形成和发展过程的引导、建设能力以及根据教师个人知识形成规律而进行培训课程设计和实施能力。

2.2.Synthesis of WMS

The specific surface area and pore volume can be determined by BET and BJH models from the calculation of N2 adsorption/desorption curve. N2 adsorption/desorption isotherms of TiO2 @WMS-COOH samples as well as their corresponding BJH pore size distribution were presented in Fig S1.The capillary condensation steps occurred at 0.4

0.8 imply the coexistence of mesopores and macropores,respectively.It can be seen that a sharp peak at～4.2 nm and a broad peaks in the range of 30–100 nm occur in the BJH pore size distribution curve.These indicate the existence of mesopores with a narrow distribution and macropores with a wide distribution,respectively.Moreover,it is interestingly found in Table 1 that the specific surface area of WMS-COOH(438.32 m2/g)is smaller than those of 0.1TiO2@WMS-COOH(485.38 m2/g)and 0.3TiO2@WMS-COOH(447.64 m2/g).This is probably due to the fact that more mesoporous channels formed by the uniformly loaded TiO2 nanoparticles in the macropores of WMS-COOH,which ultimately increase the specific surface area,but still reduce pore volume.However,when the addition of titanium source was above 0.5 ml,TiO2 nanoparticles were trend to aggregate and even some mesopores of WMS-COOH were blocked with these TiO2 as demonstrated in Fig.1e-f.Accordingly,the specific surface area and pore volume of 0.5TiO2@WMS-COOH and 0.7TiO2@WMS-COOH reduced significantly.

2.3.Synthesis of carboxyl-modified WMS(WMS-COOH)

1 g WMSs were ultrasonically dispersed in 100 ml toluene.2 ml APTES was added into the solution and then continued to be ultrasonic for 10 min.The mixture was then refluxed at 80°C for 18 h.After cooling to room temperature,the reactant was washed with ethanol and water by centrifugation and dried at 60°C to get amino-modified WMSs(WMS-NH2). 1 g WMSs-NH2 was re-dispersed in 100 ml tetrahydrofuran.Then the excess maleic anhydride was added into this solution,and then kept on stirring at room temperature for 24 h.After that,the reactant was washed with ethanol and water by centrifugation.After drying the precipitate at 60°C overnight, carboxyl-modified WMSs(WMS-COOH)was successfully obtained.

2.4.Loading TiO2 into WMS-COOH

波纹管的波纹结构有采用2个不同圆弧段和分别采用圆弧段、平直段2种方式。目前应用较多的是圆弧段与平直段相接的方式。文中即模拟圆弧与平直段相接的波纹管，并认为圆管内充满流动的流体，具体物理模型如图1所示。模型长度为180mm，直径为20mm。流体由左侧流入波纹管，由于流动为单相流动，不考虑重力对流动的影响。

Under UV irradiation as shown in Fig.5b,0.5TiO2@WMS-COOH and 0.7TiO2@WMS-COOH displayed excellent photocatalytic performance as commercial catalyst P25.They can all accomplish the degradation of RhB solution completely in 60 min.However,due to the less amount of TiO2,0.1TiO2@WMS-COOH and 0.3TiO2@WMS-COOH showed a little weak photocatalytic capacity,in which the additional 20–40 min were needed to completely degrade RhB.For RhB reference sample,its concentration droped to ～70%after 120 min UV irradiation,whereas WMS-COOH showed a negligible degradation to RhB under the same condition.This may be due to the absorption of some RhB molecules into the channels of WMS-COOH,which limits the self degradation of RhB under UV light.Overall,the photocatalytic degradation tests suggest that the photocatalytic ability of TiO2@WMS-COOH increases with the increase of titanium content,and all TiO2@WMSCOOH samples show good photocatalytic activity,which is comparable to or even better than commercial catalyst P25.

2.5.Characterization

Scanning electron microscopic(SEM)and high resolution transmission electron microscopic(HRTEM)images were taken on Hitachi S4800 and JEOL-3000F, respectively. Fourier Transform Infrared Spectroscopy was measured on Nicolet 6700.X-ray diffraction(XRD)patterns were recorded on an X-ray diffractometer(D8ADVANCE SS,Germany)with mono-chromated Cu-Kα radiation(λ=1.54060 Å)at a scanning rate of 5.0°/min.The Brunauer-EmmettTeller(BET)surface area was analyzed by nitrogen adsorption and desorption using Micromeritics ASAP2020. Using the Barrett-Joyner-Halenda (BJH)model,the pore volumes and pore size distributions are collected by the desorption branches of isotherms.UV–Vis spectra were acquired using a Shimadzu UV-2450 spectrophotometer.

2.6.Photocatalytic activity measurements

UV lamp(8 W)with a wavelength of 365 nm was applied as the light source throughout the process of photocatalytic performance measurement.The entire reaction device was coated with aluminum foil in order to prevent human health from damage.In order to avoid deposition,a magnetic stirring was employed in the whole process.The photocatalytic experiments were conducted in a 250 ml photochemical brown glass reactor,and the UV light was provided from a side of the reactor about 10 cm.Rhodamine B(RhB),which was believed to be potentially toxic and nasty linked with cancer,was chosen as model dye pollutant to analyze photocatalytic activity of the as-prepared sample.0.1 g sample and100 ml RhB solution(20 mg/L)are first mixed uniformly by magnetic stirrer for 15 min in dark condition.Then,the mixture was exposed under the UV lamp.At set intervals,2 ml of the mixture was centrifuged and washed to get its supernatant.The absorbance at 553 nm of the obtained supernatant was determined to achieve the evolution curves of photocatalytic degradation of RhB.

0.7 g WMS-COOH was ultrasonically dispersed in 20 ml ethyl acetate.After that,a certain volume of butyl titanate was added into the solution and stirred at room temperature for 30 min.Then,the mixture was poured into a hydrothermal autoclave and heated in an oven at 220°C for 12 h.After cooling to room temperature,the reactant was washed with ethanol by centrifugation.The collected precipitate was dried at 70°C overnight and then calcined at 550°C with a 2°C/min heating rate.The feed amount of butyl titanate is 0.1 ml,0.3 ml,0.5 ml and 0.7 ml,and the correspondingly obtained samples were denoted as 0.1TiO2@WMS-COOH,0.3TiO2@WMS-COOH,0.5TiO2@WMS-COOH and 0.7TiO2@WMS-COOH,respectively.

3.Results and discussion

SEM images of WMS,WMS-COOH and TiO2@WMS-COOH are shown in Fig.1.It is clear that WMSs display a spherical wrinkled mesoporous structure with a diameter around 200–400 nm(Fig.1a),which is consistent with literature reports[23].After carboxyl modified,the morphology and the mesopore structure of WMS-COOH were quite similar with those of WMS,while the diameter of WMS-COOH slightly increased(Fig.1b).Fig.1c-f shows that nano-TiO2 was successfully loaded on WMS-COOH.For 0.1TiO2@WMS-COOH,only a few sporadic TiO2 nanoparticles were observed on its surface.When the addition of butyl titanate was 0.3 ml and 0.5 ml,quite a number of uniformly distributed TiO2 nanoparticels were observed on the surface of 0.3TiO2@WMS-COOH and 0.5TiO2@WMS-COOH.However,when the addition of butyl titanate increased to 0.7 ml,as shown in Fig.1f,TiO2 gradually aggregated on the surface of WMS-COOH,like forming a thick TiO2 layer.Thus the pore structure of WMSs-COOH was hard to be observed.

TEM images of WMS,WMS-COOH and 0.3TiO2@WMS-COOH are presented in Fig.2.It is clear that both WMS and WMS-COOH show similar mesoporous channel structure,which implies that the carboxylation modification of WMS does not destroy its original structure.As can be seen from Fig.2c and e,the pore channel of 0.3TiO2@WMSCOOH was much narrower than that of WMS-COOH(as shown in Fig.2b and d),and the TEM image of 0.3TiO2@WMS-COOH had a darker contrast than pure WMS-COOH.The TEM images confirm that a plenty of TiO2 have been loaded on TiO2@WMS-COOH.

1.00 g CTAB was dissolved in 140 ml water,and then this solution was mixed with 30 ml ether,10 ml ethanol and 1.60 ml ammonium hydroxide under mechanical stirring at room temperature. After 30 min,5 ml TEOS together with 0.4 ml APTES were added dropwise into the mixture.After stirring for 4 h,the reaction was stopped by centrifuging the mixture.The collected precipitate was washed three times with ethanol and water and then dried at 60°C.The obtained sample was subsequently dispersed in the mixture of 240 ml of ethanol and 30 ml HCl followed by refluxing at 70°C for 24 h.Finally,WMSs were obtained by centrifuging and washing the precipitate with water.

Fig.1.SEM images of WMS(a),WMS-COOH(b),0.1TiO2@WMS-COOH(c),0.3TiO2@WMS-COOH(d),0.5TiO2@WMS-COOH(e),0.7TiO2@WMS-COOH(f).

Fig.2.TEM images of WMS(a),WMS-COOH(b,d),and 0.3TiO2@WMS-COOH(c,e).

Table 1 Specific surface area and pore volume of WMS-COOH and TiO2@WMS-COOH samples.

Samples Specific surface area(m2/g) Pore volume(cm3/g)WMS-COOH 438.32 0.673 0.1TiO2@WMS-COOH 485.38 0.577 0.3TiO2@WMS-COOH 447.64 0.543 0.5TiO2@WMS-COOH 391.85 0.476 0.7TiO2@WMS-COOH 361.13 0.381

The nano-TiO2 have been successfully loaded onto carboxyl modified wrinkled mesoporous silica(TiO2@WMS-COOH).The TiO2 particles exhibit a single anatase crystal and disperse inside and outside the channels of WMS-COOH.The obtained TiO2@WMS-COOH shows high adsorption capacity and excellent photocatalytic performance towards dye molecules,which is comparable to or even better than commercial catalyst P25.Moreover,it is found that the photocatalytic efficiency of TiO2@WMS-COOH can be further enhanced by increasing the calcination temperature appropriately.Based on these excellent performances,it is reasonable to conclude that TiO2@WMS-COOH is a promising candidate for the photodegradation of organic pollutants.

Fig.3.XRD patterns of WMS-COOH,TiO2@WMS-COOH and commercial catalyst P25.

Fig.4.Ranman spectra of P25 and 0.3TiO2@WMS-COOH.

In addition,we have further measured the recycling photocatalytic capacity of the samples.As shown in Fig.8,after three cycle test,the photocatalytic efficiency of 0.5TiO2@WMS-COOH has not been significantly weakened,and it can still completely degrade dye molecules in 40 min.This result implies thatTiO2@WMS-COOH has good reusing ability,and thus it may find promising applications in practical photodegradation of organic pollutants.

Fig.6.XRD patterns of 0.5TiO2@WMS-COOH calcinated at different temperatures.

奇怪的事再次发生，张万邦的右肋同样像充气的皮囊，一下将对手的拳头弹开。秦铁崖难以置信，重复出招，砰砰砰，连出数拳，结果完全一样。

Generally speaking,the photocatalytic activity of TiO2 mainly depends on its crystal properties.In order to further explore the effect of TiO2crystal on the photocatalytic performance of TiO2@WMS-COOH samples,0.5TiO2@WMS-COOH was chosen as an example to calcinate at different temperature(350°C,550°C,750°C and 950°C)in the preparation process.XRD patterns of the obtained samples are shown in Fig.6.It can be seen that the higher the calcination temperature,the stronger the characteristic diffraction peaks of the anatase of TiO2,indicating that the anatase content became more and its crystal form became more perfect with the increase of calcination temperature.Usually,when the calcination temperature exceeds 800°C,the anatase TiO2 should gradually turn into the rutile.However,as the calcination temperature up to 950°C in this study,there is still only a single anatase within 0.5TiO2@WMS-COOH,illustrating that the anatase-to-rutile phase transition temperature can be significantly improved by the presence of WMS-COOH[24–26].

Fig.5.Adsorption capacity(a)and photocatalytic degradation graphs of P25,WMS-COOH and TiO2@WMS-COOH.

Fig.7.Adsorption capacity(a)and photocatalytic degradation graphs(b)of 0.5TiO2@WMS-COOH calcinated at different temperatures.

Fig.8.Recycling photocatalytic degradation graph of 0.5TiO2@WMS-COOH calcinated at 750°C.

Fig.7a shows adsorption rate of RhB by 0.5TiO2@WMS-COOH prepared at different calcination temperatures.It can be seen that,with the increase of calcinations temperature,the adsorption capacity of the samples increases firstly and then decreases.When the calcination temperature is below 800°C,more perfect and small size TiO2 nanoparticles will be formed and uniformly load within the channels of WMS-COOH with the increase of calcination temperature,and ultimately improve the specific surface area of the samples.Therefore,the samples obtained at calcination temperature below 800°C show an increasing adsorption capacity with the increase of calcination temperature.However,when the calcination temperature increased up to 950°C,large size TiO2 grains easily formed,causing some mesoporous channels of WMS-COOH to be blocked,which finally affected the adsorption performance of the samples.Owing to the same reason,the photocatalytic performances of 0.5TiO2 @WMS-COOH prepared at different calcination temperature showed a similar trend with their adsorption capacity(Fig.7b).For the samples obtained at calcination temperature below 800°C,they displayed increasing degradation effi-ciency with the increase of calcination temperature,while the sample obtained at 950°C showed a little weaker degradation efficiency than the samples obtained at 550°C and 750°C.

In order to study the potential application of the prepared samples as photocatalysts,photocatalytic degradation of RhB was conducted.The adsorption capacity was first tested by keeping a mixture of RhB solution and these materials in dark for 24 h.Fig.5a shows the RhB adsorption capacity of P25, WMS-COOH and TiO2 @WMS-COOH samples.It is clear that all TiO2@WMS-COOH samples have a high adsorption capacity between 60%and 80%,and this can be ascribed to their high specific surface area,mesoporous structure and acidic Ti-O-Si bond.In contrast,due to its low specific surface area or the absence of Ti-O-Si bond,P25 and WMS-COOH showed a low adsorption rate below 10%.

4.Conclusion

In order to determine the presence of TiO2 crystals in the prepared samples,XRD analysis was performed by comparing the characteristic peaks of TiO2@WMS-COOH samples and commercial P25,and the results are shown in Fig.3.WMS-COOH displays a wide peak around 2θ=25°,suggesting its amorphous nature.More obvious peaks located at(101),(004),(200),(105)and(211)were observed for the all TiO2@WMS-COOH samples with increasing Ti content.These peaks well match with the JCPDS pattern 21–1272,indicating the enrichment of anatase in the TiO2@WMS-COOH samples.However,the commercial catalyst P25 shows a mixed crystal of anatase and rutile (JCPDS 21–1272/21–1276).Furthermore,raman spectrum of 0.3TiO2@WMSCOOH was also carried out to study Ti species within the samples.The peaks located at 398 cm-1,517 cm-1 and 640 cm-1 for the raman spectrum in Fig.4 quite agree with the characteristics of anatase TiO2.Therefore,both XRD and Raman results demonstrate that only anatase TiO2 are existed within the TiO2@WMS-COOH samples.

1.1 研究对象 33岁孕妇，停经25+周时，外院超声发现胎儿双肾回声增强，羊水极度过少(最大羊水深度<20mm)来本院产前诊断中心就诊，分析胎儿预后不良可能，孕妇及家属决定终止妊娠，并对胎儿进行相关遗传学分析。既往史：曾因孕29周发现胎儿双肾回声增强、羊水过少引产1次。

Acknowledgements

This work was supported by the National Natural Science Foundation of China(21875144,21802097,51778369),and Natural Science Foundation of Guangdong Province (2017A030313047,2017A030310324,2018A030313758).

Appendix A.Supporting information Supplementary data associated with this article can be found in the online version at doi:10.1016/j.pnsc.2018.11.007.

与此同时，校企合作模式还有利于企业更好的选用优秀人才，通过参与到学校的教育教学过程当中，挖掘隐藏在学校内部的优质人才资源，优先选拔和聘用该类人才可以为企业节约大量的人才资源吸引和培养成本。企业还可以通过学校这个平台来宣传企业的文化和理念，提升企业的品牌效应，吸引更多的客户和合作者。

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