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1.
以甘蔗渣为原料,采用水热合成法制备羟基磷灰石/蔗渣炭复合吸附剂--HBA,通过静态吸附试验研究HBA对As(Ⅴ)的吸附特性,并采用红外光谱和X射线光电子能谱对吸附前后的HBA进行表征,探讨其吸附As(Ⅴ)的机理.结果表明:HBA的比表面积为89.52 m2/g,pHzpc(零点电荷)=7.2,HBA上的羟基磷灰石的分子式为Ca10(PO46(OH)2.HBA吸附As(Ⅴ)的效果最佳pH为5.0~9.0.Langmuir等温吸附模型适合拟合HBA对As(V)的吸附等温线,25℃时Langmuir最大吸附量为6.76 mg/g,是蔗渣炭对As(Ⅴ)最大吸附量的20多倍.红外光谱分析表明,HBA含有的=C=O、─OH、─COOH等含氧官能团,可为化学吸附提供充足的吸附位点和提高HBA的吸附能力.XPS分析表明,HBA表面的含氧官能团[如羧基(─O─C=O,532.2 eV)、羟基(─OH,530.6 eV)]参与了吸附反应,羟基磷灰石能提高HBA吸附As(Ⅴ)的能力,被吸附到HBA表面上的As主要以AsO43-和HAsO42-形态存在.   相似文献   

2.
The removal of As(III) and As(V) from aqueous solution was investigated using waste cast iron, which is a byproduct of the iron casting process in foundries. Two types of waste cast iron were used in the experiment: grind precipitate dust (GPD) and cast iron shot (CIS). The X-ray diffraction analysis indicated the presence of Fe0 on GPD and CIS. Batch experiments were performed under different concentrations of As(III) and As(V) and at various initial pH levels. Results showed that waste cast iron was effective in the removal of arsenic. The adsorption isotherm study indicated that the Langmuir isotherm was better than the Freundlich isotherm at describing the experimental result. In the adsorption of both As(III) and As(V), the adsorption capacity of GPD was greater than CIS, mainly due to the fact that GPD had higher surface area and weight percent of Fe than CIS. Results also indicated the removal of As(III) and As(V) by GPD and CIS was influenced by the initial solution pH, generally decreasing with increasing pH from 3.0 to 10.5. In addition, both GPD and CIS were more effective at the removal of As(III) than As(V) under given experimental conditions. This study demonstrates that waste cast iron has potential as a reactive material to treat wastewater and groundwater containing arsenic.  相似文献   

3.
利用简单的碱沉淀法制备不同的水合金属氧化物,并对所得七种水合金属氧化物的磷酸根吸附等温线进行了系统的探讨比较.研究表明,25℃条件下,Al、Fe、Ni、Cu和Ce的水合金属氧化物对磷酸根的吸附最符合Langmuir线性吸附方程,而水合氧化锌和水合氧化钴吸附剂最符合线性等温线模型.所有这七种水合金属氧化物对磷酸根的吸附都...  相似文献   

4.
天然菱铁矿改性及强化除砷研究   总被引:6,自引:3,他引:3  
赵凯  郭华明  李媛  任燕 《环境科学》2012,33(2):459-468
我国高砷地下水分布广泛,经济、高效地饮用水除砷技术受到广泛关注.静态批实验采用资源丰富、价格便宜的天然菱铁矿为主要原材料,考虑灼烧温度、时间及添加黏合剂等因素确定最优改性条件使除砷效果达到最佳.结果表明,在加铝量为10 mg.g-1、350℃下恒温灼烧90 min后造粒达到强度要求并除砷效果较优.25℃、固液比为0.5 g∶50 mL、As(Ⅲ)和As(Ⅴ)初始浓度为5 mg.L-1时,吸附后溶液中残留As浓度均<10μg.L-1.静态吸附批实验结果表明,25℃时,接触反应时间为12 h可达到吸附平衡,吸附过程较好地符合Lagergren假二级吸附速率方程;最优改性天然菱铁矿对砷的吸附规律可用Langmuir和Freundlich等温吸附模型很好地描述,As(Ⅲ)、As(Ⅴ)饱和吸附容量分别可以达到1 039、1 026μg.g-1.结合XRD、SEM等研究方法和比表面及孔结构分析初步探讨天然菱铁矿改性以及除砷的主要机制.分析表明,改性后天然菱铁矿比表面积大幅度增大,孔径减小,且在表面活化生成一层圆球状的含Fe(Ⅱ)和Fe(Ⅲ)的化合物.改性天然菱铁矿是一种值得进一步研究并实际应用的除砷材料.  相似文献   

5.
改性粘土矿物的制备及其对水体中二氯喹啉酸的吸附研究   总被引:6,自引:0,他引:6  
采用固-液吸附法,以天然钙基蒙脱石为原料,硫酸和十六烷基三甲基溴化铵(HDTMAB)为改性剂,制备了3种改性蒙脱石,并借助X-射线衍射、比表面积全分析及有机碳含量测定对所得的改性蒙脱石进行表征.结果表明,先酸化后再进行有机改性所得的改性蒙脱石(AHM)不仅具有较大的比表面积、层间距,而且有机碳含量是最高的.同时,采用批量平衡实验比较了这3种改性蒙脱石和天然蒙脱石对二氯喹啉酸的吸附能力.结果表明,天然蒙脱石对二氯喹啉酸的吸附率最小,不足5%,而先酸化再进行HDTMAB改性所得的改性蒙脱石对二氯喹啉酸的吸附率最高,其对二氯喹啉酸的吸附容量约为天然蒙脱石的20倍.二氯喹啉酸在这种改性蒙脱石上吸附速率很快,吸附平衡时间为2 h,吸附动力学满足准二级动力学方程,吸附等温线可用Linear和Freundlich模型较好地拟合.  相似文献   

6.
复合吸附材料TLA的制备及其砷氟共除性能的研究   总被引:4,自引:0,他引:4  
以硫酸钛、硝酸镧和活性炭为原料,制备了新型的TLA复合吸附剂.比较了TLA和活性氧化铝除砷除氟吸附等温线、吸附动力学和pH对除砷除氟效果的影响;通过X射线衍射仪(XRD)和扫描电镜(SEM)对吸附剂进行了表征,并对吸附机理进行了探讨.结果表明,TLA对砷氟的吸附容量显著优于活性氧化铝.在pH为7,砷氟单独存在时,TLA对砷和氟的Langmuir吸附容量分别是30.3mg.g-1和27.8mg.g-1;当砷氟共存时,TLA对砷和氟的Langmuir吸附容量分别是25.1mg.g-1和17.0mg.g-1.TLA对砷、氟的吸附符合拟二级动力学方程.溶液pH值显著影响砷、氟去除效果.电荷分布多位络合模型(Charge-distribution multisite complexation model,CDMUSIC)能准确模拟砷、氟的吸附行为.  相似文献   

7.
Three organo-montmorillonites were prepared using surfactants, and their adsorption behaviors toward sulfamethoxazole(SMX) were investigated. The surfactants used were cetyltrimethyl ammonium bromide(CTMAB), 3-(N,N-dimethylhexadecylammonio) propane sulfonate(HDAPS) and 1,3-bis(hexadecyldimethylammonio)-propane dibromide(BHDAP). The properties of the organo-montmorillonites were characterized by X-ray diffraction, scanning electron microscopy and N2adsorption–desorption isotherm measurements. Results showed that the interlayer spacing of montmorillonite was increased and the surface area as well as the morphology were changed. Batch adsorption experiments showed that the surfactant loading amount had a great effect on the adsorption of SMX. The adsorption process was p H dependent and the maximum adsorption capacity was obtained at p H 3 for HDAPS-Mt, while CTMAB-Mt and BHDAP-Mt showed a high removal efficiency at 3–11. The adsorption capacity increased with the initial SMX concentration and contact time but decreased with increasing solution ionic strength.Kinetic data were best described by the pseudo second-order model. Equilibrium data were best represented by the Langmuir model, and the Freundlich constant(n) indicated a favorable adsorption process. The maximum adsorption capacity of SMX was 235.29 mg/g for CTMAB-Mt, 155.28 mg/g for HDAPS-Mt and 242.72 mg/g for BHDAP-Mt. Thermodynamic parameters were calculated to evaluate the spontaneity and endothermic or exothermic nature. The adsorption mechanism was found to be dominated by electrostatic interaction,while hydrophobic interaction played a secondary role.  相似文献   

8.
载铁活性炭对水中草甘膦吸附性能研究   总被引:4,自引:0,他引:4       下载免费PDF全文
通过浸渍-焙烧法制备载铁活性炭,并用SEM电镜分析了载铁活性炭表面形态,研究了载铁活性炭(Fe-AC)对草甘膦溶液的吸附等温线和吸附动力学,并分析了各种影响因素对载铁活性炭吸附性能的影响.实验表明,Freundlich方程可以对Fe-AC草甘膦吸附等温线进行很好拟合,最大吸附量约为5.8mmol/g;其吸附动力学过程用Lagergren方程拟合,吸附速率常数在0.088min-1左右,且随着温度的升高逐渐减小.根据Kannan & Sundaram颗粒内扩散模型拟合,颗粒内扩散速率常数kp大于10mg·min-1/2/g,并随着起始温度的升高而减小.由于草甘膦的存在形态和Fe-AC材料表面性质的变化,AC-Fe对草甘膦的吸附能力随水溶液的pH升高而降低.NaCl的存在产生拮抗效应使得Fe-AC对草甘膦的吸附容量大大下降,随着NaCl浓度增加至4g/L后,盐析效应开始占主导地位,使得Fe-AC的吸附容量略有增加;由于草甘膦分子的空间位阻效应和亚磷酸根与载铁活性炭表面形成较强的络合物,使得随亚磷酸根浓度的升高Fe-AC对草甘膦的吸附量持续下降.  相似文献   

9.
以十六烷基三甲基溴化铵(CTMAB)为表面活性剂,采用共沉淀法制得La2O3纳米颗粒。利用扫描电子显微镜(SEM)、X射线衍射(XRD)和比表面积分析仪(BET)对La2O3纳米颗粒进行分析。采用批实验考察了溶液pH、典型阴离子和离子强度等因素对La2O3纳米颗粒吸附溶液中As (Ⅲ)的影响,并对吸附动力学、吸附等温模型及吸附机理进行研究。结果表明:添加质量分数为0.2%的CTMAB时制得的La2O3对As (Ⅲ)的吸附效果最好。当溶液pH为5~9时,As (Ⅲ)去除率较高,可达85.36%。溶液中共存的SO2-4和CO2-3对As (Ⅲ)的吸附影响较小,而SiO2-3和PO43-增加到10 mmol/L时,As (Ⅲ)去除率从85.36%分别降低至39.14%和25.36%。离子强度对As (Ⅲ)的吸附影响较小,表明该吸附过程为内层吸附。La2O3纳米颗粒对As (Ⅲ)的吸附符合伪二级反应动力学和Langmuir吸附等温模型,表明该吸附为单分子层吸附,理论最大吸附量为45.5 mg/g。La2O3纳米颗粒吸附As (Ⅲ)的机理分析为La2O3表面羟基化后产生的羟基基团La—OH与As (Ⅲ)反应生成单齿或双齿络合物,从而将As (Ⅲ)从水溶液中去除。  相似文献   

10.
类水滑石Mg/Zn/Al焙烧产物对高氯酸盐的吸附   总被引:4,自引:4,他引:0  
王红宇  刘艳 《环境科学》2014,35(7):2585-2589
利用类水滑石Mg/Zn/Al的焙烧产物对ClO-4进行吸附性能研究,通过类水滑石表面结构X射线衍射分析并探讨其吸附等温、动力学模型,并研究了焙烧温度、Mg/Zn/Al质量比、溶液pH值、吸附时间及吸附剂投加量等因素对类水滑石Mg/Zn/Al吸附ClO-4的性能影响.结果表明在500℃下焙烧4 h,Mg/Zn/Al质量比为2∶1∶1的类水滑石对ClO-4去除效果较好,吸附容量最大且对溶液pH值有较好的适用范围.经500℃焙烧的类水滑石吸附ClO-4的动力学拟合结果符合二级反应动力学模型,吸附等温线符合Langmuir及Freundlich吸附等温模型.  相似文献   

11.
为探究针铁矿不同晶面对As(Ⅴ)的吸附能力,该研究制备两种具有不同比例{021}/{110}晶面的针铁矿,利用XRD、FTIR、N2吸附脱附等温线、SEM、TEM等技术表征材料的晶体结构、比表面积和表面形貌等情况. 通过等温吸附和吸附动力学试验,研究不同初始As(Ⅴ)浓度、pH和竞争阴离子影响下,两种针铁矿吸附As(Ⅴ)的差异性. 结果表明:①制备的针铁矿Goe-A和Goe-B均为高纯针铁矿,Goe-A和Goe-B的比表面积分别为92.76和46.78 m2/g. ②As(Ⅴ)在针铁矿表面的吸附更符合Freundlich等温吸附模型和准二级动力学模型,表明吸附是以多层吸附和化学吸附为主;经比表面积归一化后,发现含有更高比例{021}/{110}晶面的Goe-B表面拥有更好的吸附性能,在pH=4时吸附量达到0.304 mg/m2,是Goe-A的1.57倍. ③pH会影响针铁矿的吸附,吸附量随着pH的增加而降低,而在碱性条件下Goe-B表现出更强的吸附能力. 随As(Ⅴ)浓度的增加,大量配体吸附引起的点位竞争效应大于pH变化引起的静电力作用. ④吸附前后XRD的变化表明,As(Ⅴ)主要吸附在针铁矿表面,而不是结合到针铁矿的晶体结构中;而FTIR和XPS分析发现,As(Ⅴ)通过与Fe—OH配体交换形成了新的络合物(Fe—O—As)吸附在针铁矿表面. 研究显示,含有更高比例{021}/{110}晶面的针铁矿表现出更强的吸附性能,是修复环境砷污染的理想吸附剂.   相似文献   

12.
针对含重金属Sb(Ⅲ)废水处理问题,采用液相还原法制备出高效的还原氧化石墨烯负载纳米零价铁(nZVI/rGO)复合吸附材料,并采用多种技术手段对所制备的nZVI/rGO复合材料进行表征.同时,复合材料中nZVI的负载量、吸附剂投加量、初始pH值以及反应温度等因素对废水中Sb(Ⅲ)吸附去除效果的影响被全面考察,并进一步对吸附过程进行吸附等温线和吸附动力学拟合.结果表明,在25℃,pH为3.0时,当nZVI负载量为70wt%,nZVI/rGO投加量为0.5g/L时,Sb(Ⅲ)的去除率最高,140min内可达99.7%.该吸附过程符合准二级动力学模型与Langmuir等温吸附模型,因此nZVI/rGO被证实是一种高效的Sb(Ⅲ)吸附材料.  相似文献   

13.
Humic acid-immobilized amine modified polyacrylamide/bentonite composite (HA-Am-PAA-B) was prepared and used as an adsorbent for the adsorption of cationic dyes (Malachite Green (MG), Methylene Blue (MB) and Crystal Violet (CV)) from aqueous solutions. The polyacrylamide/bentonite composite (PAA-B) was prepared by intercalative polymerization of acrylamide with Nabentonite in the presence of N,N0-methylenebisacrylamide as a crosslinking agent and hexamethylenediammine as propagater. PAA-B was subsequently treated with ethylenediammine to increase its loading capacity for HA. The surface characterizations of the adsorbent were investigated. The adsorbent behaved like a cation exchanger and more than 99.0% removal of dyes was detected at pH range 6.0–8.0. The capacity of HA-Am-PAA-B was found to decrease in the following order: MG > MB > CV. The kinetic and isotherm data were interpreted by pseudo-second order rate equation and Freundlich isotherm model, respectively. Experiments were carried out using binary solute systems to assess the competitive adsorption phenomenon. The experimental isotherm data for each binary solute combination of MG, MB and CV were analyzed using Sheindrof-Rebhun-Sheintuch (SRS) (multicomponent Freundlich type) equation.  相似文献   

14.
A novel illite@carbon (I@C) nanocomposite adsorbent has been synthesized via a facile hydrothermal carbonization process (HTC) using glucose as carbonaceous source and illite as the carrier. The morphology, microstructure and surface properties of the prepared nanocomposite adsorbent were analyzed by FESEM, TGA, XRD, FT-IR and Zeta potential measurements. Batch experiments were carried out on the adsorption of Cr(VI) to determine the adsorption properties of the composite. The adsorption of Cr(VI) onto the I@C nanocomposite was well described by the pseudo-second-order kinetic model and Langmuir isotherm. Compared with the illite and carbon material (SC) separately, the prepared I@C nanocomposite adsorbent exhibited enhanced adsorption performance for Cr(VI) with a maximum adsorption capacity of 149.25 mg/g, which was higher than that of most reported adsorbents. In addition, the adsorption process was spontaneous and endothermic based on the adsorption thermodynamics study. The adsorption of Cr(VI) by I@C was highly pH-dependent and the optimum adsorption occurred at pH 2.0. The Zeta potential analysis results indicated that the electrostatic interactions between anionic Cr(VI) and the positively charged surface of the adsorbent might be critical to the adsorption mechanism. This study demonstrated that the I@C nanocomposite should be a promising candidate for a low-cost, environmental friendly and highly efficient adsorbent for the removal of toxic Cr(VI) from wastewater.  相似文献   

15.
Preparation of photocatalytic regenerationable activated carbon (AC) is the key step for the practical application of in situ regeneration of exhausted AC. A novel photocatalytic regenerationable AC was prepared by sol-gel TiO2 in this work. The adsorption and regeneration performance of TiO2/AC were evaluated using phenol as model compound. Scanning electron microscope (SEM) and nitrogen (77 K) adsorption isotherm were used to determine the surface area, pore structure and the distribution of TiO2. The results showed that with the increase of TiO2 loading, adsorption capacity of TiO2/AC decreased and the regeneration efficiency increased. The photocatalytic regenerationable AC with suitable TiO2 loading (2 wt%) exhibited suitable adsorption capacity and regeneration efficiency. TiO2 located mainly in the entrance of macro-pore of carbon. The prepared TiO2/AC exhibited similar surface structure and pore structure with material carbon.  相似文献   

16.
由于自然和人为活动导致自然水体和土壤被As(砷)污染,严重危及生态环境并已受到广泛关注.为实现更大程度地去除含As废水的新型吸附材料,以废弃蛋壳为原材料,采用超声波法制备多孔状且较大比表面积的Na-Si-CHAP[Ca10-xNax(PO46-y-z(SiO4z(CO3y(OH)2-α,载钠硅碳羟基磷灰石],深入分析去除含As(Ⅴ)废水的吸附特性.通过BET比表面积、扫描电镜(SEM)、EDX(能量色散X射线光谱)、X-射线衍射(XRD)等手段对样品进行表征,并进一步探讨了pH、吸附时间、初始ρ[As(Ⅴ)]以及反应温度等因素对吸附效果的影响.结果表明:在pH为6.0、作用时间为60 min、反应温度为313 K等优化条件下,0.2 g Na-Si-CHAP对100 mL 30 mg/L含As(Ⅴ)废水的去除率和平衡吸附容量分别为96.53%和14.48 mg/g.Langmuir等温吸附模型较好地拟合了吸附试验数据,313 K下相关系数(r2)高达0.998 0,饱和吸附容量达46.73 mg/g,明显高于其他同类材料;准二级动力学模型可较好地描述该吸附行为,相关系数高达0.999 9;热力学参数△G(吉布斯自由能变)、△H(焓变)和△S(熵变)的计算值显示,该吸附过程为自发吸热过程.研究显示,Na-Si-CHAP作为一种吸附剂,对含As(Ⅴ)的去除效果明显优于同类材料.   相似文献   

17.
A hydrotalcite with Mg/AI molar ratio 2 was prepared by co-precipitation method and was characterized by XRD, TG/DTA, Zeta potential and BET surface area. The hydrotalcite was calcined at 500℃, with the dehydration from interlayer, the dehydroxilation from the brucite-like layer and the decomposition of carbonate successively, transformed into the mixed oxide type. The removal of thiocyanate from aqueous solution by using the original hydrotalcite and calcined hydrotalcite (HTC-500) was investigated. The results showed that the thiocyanate adsorption capacity of calcined hydrotalcite was much higher than that of the original form. Calcined hydrotalcite was particularly effective at removing thiocyanate, and that the effective range of pH for the thiocyanate removal are between 5.5-10.0. The experimental data of thiocyanate removal fit nicely with Langmuir isotherm, and the saturated adsorption uptake was 96.2 mg SCN-/g HTC-500. The adsorption of thiocyanate by calcined hydrotalcite follows first-order kinetics. And the intercalation to the structure recovery for calcined hydrotalcite. But the presence of additional anions could affect the adsorption behavior of thiocyanate.  相似文献   

18.
锆改性沸石对水中磷酸盐和铵的吸附特性   总被引:5,自引:0,他引:5       下载免费PDF全文
林建伟  詹艳慧  陆霞 《中国环境科学》2012,32(11):2023-2031
采用锆对天然沸石进行改性,并研究了锆改性沸石对水中磷酸盐和铵的吸附特性.结果表明,锆改性沸石对水中磷酸盐和铵均具有很好的吸附能力.锆改性沸石对水中磷酸盐和铵的吸附动力学过程满足准二级动力学模型.Langmuir、Freundlich和Dubinin–Radushkevich(D–R)等温吸附模型可以很好地描述锆改性沸石对水中磷酸盐的等温吸附行为.Langmuir等温吸附模型可以很好地描述锆改性沸石对水中铵的等温吸附行为.由Langmuir等温吸附模型计算得到锆改性沸石对磷酸盐和铵的最大吸附容量分别达到26.2,7.82 mg/g.热力学参数表明锆改性沸石对水中磷酸盐的吸附是自发的吸热反应过程.锆改性沸石对水中磷酸盐的吸附能力随着pH值的增加而降低.当pH4~8时,锆改性沸石对水中铵的吸附能力较高;当pH低于4或高于8时,对铵的吸附能力下降.水中共存的Cl-、SO42-、HCO3-和NO3-等阴离子对锆改性沸石吸附磷酸盐的影响很小,而共存的SiO32-对磷酸盐的吸附则具有较强的负面影响.水中共存的Ca2+和Mg2+对锆改性沸石吸附铵的影响较小,而共存的K+和Na+对铵的吸附则具有较强的负面影响.锆改性沸石吸附水中磷酸盐的主要机制是阴离子配位体的交换,吸附水中铵的主要机制是与沸石中可交换阳离子的离子交换.  相似文献   

19.
A fibrous strong base anion exchanger (QAPPS) was prepared for the first time via chloromethylation and quaternary amination reaction of polyphenylene sulfide fiber (PPS), and its physical-chemical structure and adsorption behavior for Cr(VI) were characterized by FT-IR, Energy Dispersive Spectrometry, TG-DTG, elemental analysis and batch adsorptive technique, respectively. The novel fibrous adsorbent could effectively adsorb Cr(VI) over the pH range 1-12, the maximum adsorption capacity was 166.39 mg/g at pH 3.5, and the adsorption behavior could be described well by Langmuir isotherm equation model. The adsorption kinetics was studied using pseudo first-order and pseudo second-order models, and the t1/2 and equilibrium adsorption time were 5 and 20 min respectively when initial Cr(VI) concentration was 100 mg/L. The saturated fibers could be regenerated rapidly by a mixed solution of 0.5 mol/L NaOH and 0.5 mol/L NaCl, and the adsorption capacity was well maintained after six adsorption-desorption cycles.  相似文献   

20.
硫酸盐还原颗粒污泥对Cr的吸附机理解析   总被引:1,自引:1,他引:0  
以硫酸盐还原颗粒污泥作为研究对象,进行Cr的吸附容量研究及吸附等温线拟合,测定颗粒污泥中的硫化物含量、对比实验前后颗粒污泥的表面形态和微生物组成并采用傅里叶红外变换光谱(FTIR)分析颗粒污泥的表面基团。结果表明,颗粒污泥对Cr的吸附容量为6.84 mg/g,吸附过程可用Langmuir吸附等温式描述。颗粒污泥中硫化物含量达9.868 mg/g(湿重),对应每克颗粒污泥对Cr的最大吸附量可达10.69 mg;颗粒污泥表面生长大量的微生物,以杆菌为主,颗粒污泥表面丰富的微孔结构及微生物所分泌的胞外物均可有效吸附溶液中的Cr;FTIR分析结果显示,颗粒污泥中包含大量C=O、C-N及-S等基团,这些基团均可通过与C(rⅥ)或C(rⅢ)之间的静电吸附作用吸附溶液中的Cr。研究表明化学与生物吸附作用在硫酸盐还原颗粒污泥吸附溶液中的Cr过程中起到了重要的作用。  相似文献   

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