• <tr id="yyy80"></tr>
  • <sup id="yyy80"></sup>
  • <tfoot id="yyy80"><noscript id="yyy80"></noscript></tfoot>
  • 99热精品在线国产_美女午夜性视频免费_国产精品国产高清国产av_av欧美777_自拍偷自拍亚洲精品老妇_亚洲熟女精品中文字幕_www日本黄色视频网_国产精品野战在线观看 ?

    Preparation of Biomanganese Oxide-biochar Composite and Its Remediation of Arsenic Contamination

    2023-06-27 09:26:42DilixiatiAbulizi
    Asian Agricultural Research 2023年5期

    Dilixiati Abulizi

    College of Tourism, Urumqi Vocational University, Urumqi 830001, China

    Abstract [Objectives] To prepare biomanganese oxide/biochar composite (BMO-BC) and examine its remediation performance on arsenic contamination. [Methods] The BMO-BC was prepared by cultivating Pseudomonas putida MnB1 in the presence of Mn2+ and biochar. [Results] The initial concentration of Mn2+ in the culture system had no significant effect on the growth rate and domestication cycle of Pseudomonas putida MnB1. The results of SEM-EDS and XRD analysis confirm that the adsorbent prepared in this experiment was a composite of biomanganese oxide and biochar particles. The results of arsenic pollution removal test in simulated environment showed that the in-situ formed BMO-BC composite had certain removal effect on As (III) and the presence of biochar particles and manganese dioxide in the reaction system and the manganese oxidation ability of microbial strain MnB1 affect its remediation performance to As (III). [Conclusions] When the initial concentration is in the range of 0-10.0 mg/L, the isothermal adsorption data of BMO-BC on As (III) conforms to the Langmuir model.

    Key words Arsenic pollution, Bio-manganese oxide, Biochar, remediation

    1 Introduction

    Arsenic is a highly toxic and carcinogenic non-metallic substance. As long-term intake of water contaminated with arsenic can cause many serious diseases, the presence of arsenic in groundwater has become a worldwide concern[1-2]. In aquatic systems, arsenic exists mainly in inorganic forms with two predominant species: As (V) and As (III)[2]. The As (III) species is 25-60 times more toxic than As (V). Due to the increasing toxicity and flow characteristics of As (III) compared to As (V), it is necessary to use a technology that simultaneously removes and detoxifies As (III)[3].

    For decades, researchers have been working on methods to remove arsenic from contaminated water at minimal cost. Chemical precipitation, membrane separation, ion exchange, electrochemical methods, adsorption, etc. are all methods for removing arsenic mentioned in the literature[4-5]. In an environment with low arsenic content, the adsorption method has advantages over other methods, including low cost, easy operation, and low dosage of chemical additives[6].

    In recent years, biochar has been widely used to remove pollutants in water, which provides a low-cost, environmentally friendly solution for the immobilization of pollutants in water[7]. Due to the negative charge on the surface of most biochar, it is difficult to adsorb arsenic in anion forms such arsenite [As (V)] or arsenite [As (III)][8]. Therefore, researchers have developed a variety of methods to modify biochar to improve its ability to adsorb anions, such as the combination of biochar and manganese oxide[9-10]. According to literature reports, biochar modified by manganese hydroxyl oxide has a high adsorption capacity for arsenic pollutants in aqueous solution[11-12]. Previous studies have also shown that the adsorption capacity of biological manganese oxide (BMO) is higher than that of chemical manganese oxide[13], and BMO with high surface charge and oxidation capacity is a very effective adsorbent and oxidant[14].

    Under natural conditions, the rate of microbial manganese oxidation can reach 100 000 times that of abiotic processes[15]. Nelson[16]reported that the manganese oxide produced byLeptothrixdiscophoraSS-1 showed a strong adsorption capacity for Pb2+. Toner[17]investigated the mechanisms of Zn adsorption to a biogenic Mn oxide within a biofilm produced by model soil and freshwater MnII-oxidizing bacteriaPseudomonasputida.

    In view of the fact that nano-scale BMO particles are difficult to separate and purify from water, and have great toxicity to the environment, they have not been widely used in the study of adsorption and removal of pollutants in water[18]. Fixing BMO on a solid carrier that is large in size and easy to separate helps to improve the practical application of BMO in water pollution treatment. In addition, its high surface energy can prevent the aggregation of BMO nanoparticles[19].

    In this paper, manganese oxide produced by manganese oxidizing bacteria is loaded on the surface of biochar, and a composite material of biochar and biomanganese oxide is prepared to study its remediation performance for arsenic pollution.

    2 Materials and methods

    2.1 Mn oxidizing bacteria and biocharPseudomonasputidaMnB1 was purchased from American Type Culture Collection (ATCC,number 23483), used as the Mn-oxidizing bacterium. Nutritional broth (#3 N/B, DifcoTM, Sigma-Aldrich, USA) was cultured and activated at 30 ℃ while agitating at 150 rpm for subsequent experiments. The medium used in the experiment of manganese oxidation is G/M medium.

    We chose biochar as a solid support for BMO. It is well known that biochar is a carbon-rich fine-grained porous material, and it has a great affinity for heavy metals due to the presence of porous structures and various functional groups such as carboxyl groups, hydroxyl groups and phenolic hydroxyl groups[20-21].

    Cotton stalk biochars obtained from Xinjiang Academy of Agricultural Sciences and were treated by the following procedure before use. Briefly, the obtained biochar samples were grounded and sieved to 200 meshes, 5.0 g of biochar was weighed and treated with 1 000 mL of 0.1 M HCl solution for 4 h and repeated 3 times to remove ash. It was filtered, neutralized by washing with deionized water, dried at 110 ℃ for 24 h, sieved again, and stored in a desiccator for adsorption experiments.

    2.2 Synthesis of biomanganese oxide/biochar composite (BMO-BC)The BMO-BC was prepared by incubation of MnB1 in the presence of the Mn2+and biochar. We expected that loading BMO onto biochar can improve its ability to absorb arsenic as heavy metals. The specific preparation process of BMO-BC is as follows:

    Under aseptic conditions, 3.0 g biochar particles were placed in Erlenmeyer culture bottles containing 300 mL growth medium (G/M) prepared according to a previous study[18]. The composition of the G/M was 0.5 g/L yeast extract, 0.5 g/L casamino acids, 1 g/L glucose, 0.222 g/L CaCl2, 0.811 8 g/L MgSO4·7H2O, 0.001 g/L FeCl3·6H2O, 2.38 g/L 4-(2-hydroxyethyl) piperazine-1-ethanesulphonic acid (HEPES) buffer, and 1 mL/L trace element solution. The trace element solution was prepared with 6.4 mg/L CuSO4, 44 mg/L ZnSO4·7H2O, 20 mg/L CoCl2·6H2O, 13 mg/L Na2MoO4·2H2O, and DDIW. Before that, biochar and G/M were sterilized for 15 m. Then 3 mL MnB1 cell suspension was added into the culture system and placed in an incubator at 26 ℃ for incubation at a speed of 150 rpm.

    HEPES buffer (final concentration is 20 mM) and MnCl2stock solution were added by filter sterilization method, After the final concentration of Mn2+was adjusted to 10 mmol /L, the culture system was moved to a shaking bed at 26 ℃ for about 5 d, and the culture system without biochar and Mn2+was used as the control.

    The concentration of high valent manganese (Mn3+, Mn4+) in parallel medium was determined by Leucoberbelin Blue (LBB) dying method[22]at different time intervals. Biochar particles loaded with BMO were separated and washed with deionized water several times before purification. The BMO/biochar complex extracted in our experiment was then purified by the method described by Mandernack[23]. The purpose of purification is to remove the cells, residual organic materials and adsorbent surface adhesion of anions that may affect the adsorption and characterization of heavy metals.

    2.3 Removal of arsenic byinsitusynthesized BMO-BC

    Sodium arsenite was used to simulate arsenic polluted water. The 100 mg biochar sample was accurately weighed in several 250 mL conical flasks and sterilized at 121 ℃ under high pressure. The final concentration of Mn2+in the mixed solution adjusted to 10 mmol/L by pouring 100 mL growth medium (G/M) sterilized at 121 ℃ and filter sterilizide liquor of MnCl2. After 12 h of activation, the preserved strains were inoculated in 1% proportion on the aseptic operating table. The culture system was placed in a shaker at 26 ℃ for about 10 h. The As (III) reserve solution was filtered and dripped into the culture system. The experimental system with As (III) concentration of 0, 1.96, 4.76 and 9.09 mg/L was compared with the system without biochar and Mn (II) addition. In addition, the culture system without microbial inoculation with heavy metal concentration of 9.09 mg/L was used as the control group.

    2.4 Isothermal adsorption of As (III) by BMO-BCAccurately weighed 50 mg BMO-BC particles in a 50 mL centrifugal tube. Different amounts of As (III) stock solution and deionized water were added to adjust the final concentration of As (III) to 0.1, 0.5, 1.0, 2.5, 5.0 and 10 mg/L, The solution volume was adjusted to 40 mL, and the pH was adjusted with 0.1 M NaOH and 0.1 M HCI. It oscillates for 24 h at a rate of 130 rpm in a rotary oscillator at 25 ℃. The adsorbed mixture was filtered by a 0.22 μm filter membrane. The concentration of heavy metal ions in filtrate was determined by atomic fluorescence spectrophotometry (AFS-810, Jitian, Beijing, China). The adsorption capacity and adsorption rate were calculated according to the difference between the concentration of heavy metal ions before and after the adsorption test. The effects of the initial concentration of heavy metal ions and the initial pH of solution on the adsorption process were also discussed.

    2.5 Analytical techniquesThe analysis of arsenic in samples was completed by atomic fluorescence spectrometer (AFS-810, Jitian, Beijing, China). The surface properties of BMO/BC were characterized by SEM-EDS, FTIR-ATR and XRD.

    3 Results and analysis

    3.1 Characterization of BMOThe growth curve of MnB1, a manganese-oxidizing bacterium, is shown in Fig.1. It can be seen that MnB1 enters a stable period when it grows to 10-15 h. It was found in the experiment that when the Mn2+concentration was set within the range of 0-600 mm, the growth rate and domestication period of MnB1 were not significantly affected by the initial concentration of Mn2+. Our experimental results are close to those reported by other scholars. MnB1 entered a stable period after 12 h of cultivation[24]. There was no significant difference in the shape of bacterial growth curves cultured at different Mn2+concentrations.

    Fig.1 Growth rate of Pseudomonas putida MnB1

    The effect of initial Mn (II) concentration on BMO formation is shown in Fig.2. As shown in Fig.2, the BMO concentration generated in the culture system increases with the increase of the initial Mn2+concentration. We also noted that high-valent manganese oxides such as manganese dioxide could not be detected when Mn2+was not added to the culture system. When the initial concentration of Mn2+was equal to 0, 1.0, 2.0 and 4.0 mM respectively, the content of MnOx,i.e.BMO, produced by the oxidation of MnB1 in the culture system was 0.71, 1.35, 2.07 and 2.79 mmol/L, respectively. The change trend of BMO content is close to its theoretical value[25].

    Fig.2 Effects of initial Mn (II) concentrations on the generation of BMO

    3.2 Surface Properties and Characterization of BMO-BCThe results of scanning electron microscopy (SEM) comparison of biochar samples with BMO-BC are shown in Fig.3. SEM results showed that BMO loading had some effect on the surface structure of biochar (Fig.3b). Unmodified biochar (Fig.3a) has a rich and smooth pore structure that makes it easier to adsorb other substances or oxidize metals. However, the orifice and surface of BMO modified biochar are roughened by manganese oxide. The modified biochar has some impurities attached to its surface pores, which are probably manganese oxides. When the pores of the biochar are blocked, the surface area and pore diameter of the biochar will decrease.

    Fig.3 SEM images of pristine biochar (a) and BMO coated biochar (b)

    In order to further characterize the surface structure and microscopic characteristics of BMO-BC complex, BET specific surface area, BJH pore volume, EDS, XRD and FTIR spectra of the composite were analyzed. The results of SEM and EDS analysis of BMO-BC complex amplified 1 000, 3 000, 5 000 times are shown in Fig.4.

    Note: a. Mag=1.00KX; b. Ma=1.00KX on different area; c. Mag=3.0KX; d. Mag=5.0KX; e. EDS analysis.Fig.4 SEM images of BMO coated biochar

    The surface element content of BMO-BC measured by X-ray energy spectrometer is shown in Table 1. The weight percentages of C, O and Ca in the original biochar were 77.58%, 16.51% and 3.60%, respectively; in addition, the weight percentages of K, Mg, P and S were 0.57%, 0.70%, 0.59% and 0.44%, respectively; the weight percentages of C, O and Ca changed to 17.30%, 48.64% and 0.44% after loading of BMO, and the content of O increased from 16.51% to 48.64%; the weight percentage of Mn element in BMO-BC is 0.18%. Elements O and Mn detected by X-ray energy spectrometer prove the existence of manganese oxide.

    Table 1 Weight percentage of major elements in BC and GBC %

    Table 2 shows the BET specific surface area and BJH porosity of BC and BMO-BC materials. It can be seen from the table that the specific surface area of biochar BET decreased from 32.365 to 26.065 cm2/g, and the pore volume decreased from 0.023 to 0.019 cm3/g. SEM image (Fig.4) shows that BMO and other impurities produced by microbial oxidation hinder the pore diameter of biochar, which can explain the decrease of surface area and pore diameter in BET and BJH measurements.

    Table 2 Pore structure parameters of BC and BMO-BC

    The surface properties of biochar composites were further analyzed by XRD technique in order to characterize whether the Mn oxides were successfully loaded onto the composite adsorbent. The results are shown in Fig.5. According to literature reports, the characteristic peak appears when the 2 Theta values of 12.3 and 24.88 in the XRD spectrum of natural sodium manganese minerals[24-26]. In this study, the XRD spectra of BMO-BC formed byin-situoxidation of biochar and MnB1 showed characteristic peaks consistent with those of natural sodium manganese ore. As shown in Fig.5, the relative strength and position of several crystal peaks in the XRD spectrum are very close to Mn2O3peak[17,27].

    Fig.5 XRD diffraction patterns of BMO-BC

    3.3 Removal of trivalent arsenic byin-situformed BMO-BC

    In order to study the removal effect ofin-situformed BMO-BC on arsenic (III) in simulated polluted environment, the removal efficiency of As (III) in BMO-BC was tested at different initial concentrations of heavy metals (Fig.6.).

    Fig.6 Change of As (III) concentration in the media with in situ formed BMO-BC at different As (III) initial concentration

    As can be seen from Fig.6, As (III) concentration in the system gradually decreases with the passage of time. When the initial concentrations of As (III) were 1.96, 4.76 and 9.09 mg/L, the final concentrations of As (III) in the system after 72 h were 0.91, 2.62 and 5.73 mg/L, and the removal rates of As (III) were 53.41%, 44.78% and 36.89%, respectively. In the experimental group without Mn (II), the experimental group without BC and the control group (with As (III) initial concentration of 9.09 mg/L, biochar 100 mg (III), Mn (II) concentration of 10 mM, without MnB1 inoculation), the final concentration of As (III) after 72 h of shaker culture was 6.92, 8.18 and 8.10 mg/L, respectively. The removal rates were 23.85%, 9.91% and 10.87%, respectively. In the control group and the experimental group without BC, the removal rate of As (III) was only about 10%. On the one hand, the removal rate of As was related to the manganese oxidation (partial trivalent arsenic was oxidized to pentavalent arsenic from solution) produced by strain MnB1[28], and on the other hand, the microbial strain and biochar itself has limited adsorption capacity for As. The removal rate of As (III) in the Mn (II)-free group was 23.85%, indicating that in the Mn (II)-free culture system, the removal rate of about 20% of As (III) was related to the adsorption of bacteria and biochar.

    From the above analysis, it can be seen that the removal rate of As (III) reaches its highest value within 12 h, and there is no significant change thereafter. In summary, BMO-BC adsorbs As (III) at a faster rate, and adsorption and desorption occur simultaneously as the experiment progresses.

    3.4 Isothermal adsorption of As (III) by BMO-BCIn order to better reveal the effect of biological manganese oxide modification on improving the adsorption capacity of arsenic in biochar, we conducted an isothermal adsorption experiment usingin-situformed BMO-BC as adsorbent. Results of isothermal adsorption of BMO-BC complex on As (III) are shown in Fig.7. When the initial concentration of As (III) was 0.1, 0.5, 1.0, 2.5, 5.0, 10.0 mg/L, the maximum sorption amount and maximum removal rate of As (III) were 2.12 mg/g and 26.5% respectively after 24 h of adsorption. The maximum adsorption capacity and maximum removal rate of As (III) in the control group (with biochar and bacteria, without Mn2+) were 0.95 mg/g and 11.9%, respectively. This result reveals that, in the absence of divalent manganese, the adsorption capacity of the composite formed by biochar and strain MnB1 is very low, while the manganese oxide produced by microbial oxidation can improve the adsorption capacity of biochar.

    Fig.7 As (III) adsorption amount of BMO-BC at different initial concentration

    The results of data fitting to the Langmuir isotherms are given in Table 3. They showed that Langmuir isotherms show a good fit to the experimental data, as indicated by the very high values of the correlation coefficient (R2>0.99). The applicability of the isotherms to the arsenic adsorption shows that monolayer adsorption on the surface of the adsorbent are possible. It is shown in Fig.7 that with the increase of equilibrium concentration, the adsorption capacity of As (III) of the control group (with biochar and strain, without Mn2+) and BMO-BC complex gradually increased. The maximum adsorption capacity Qmwas 2.77 and 5.57 mg/g, the Langmuir adsorption coefficientbwas 0.041 91 and 0.065 11, andR2was 0.997 9 and 0.999 7, respectively (Fig.8). Coating BMO on the biochar surface increased the maximum adsorption amount of As (III) on adsorbents, indicating that modifying the biochar surface with BMO enhanced its adsorption capacity for As (III).

    Table 3 Parameters of the isotherms for As (III) adsorption onto BMO-BC

    Fig.8 Adsorption isotherms for As (III) onto adsorbents

    4 Conclusions

    BMO-BC, a new adsorption material, was synthesized using a manganese-oxidizing bacterium and biochar to investigate its removal performance of arsenic pollution. We reached the following conclusions. (i) The growth rate and domestication period ofPseudomonasputidaMnB1 were not significantly affected by the initial concentration of Mn2+in the culture system when the concentration of Mn2+changed from 0 to 600 mM. (ii) The changing trend of BMO content produced by Manganese Oxidizing Bacteria MnB1 is close to its theoretical value. (iii) The results of scanning electron microscopy (SEM) and X-ray energy dispersive spectrometer (EDS) indicate that the signals of O and Mn on the surface of the composite prove the existence of manganese oxide. XRD analysis further confirmed that the adsorbent prepared in the experiment was biochar-biomanganese oxide complex. (iv) Simultaneous removal of arsenic in simulated polluted environment was carried out. The results showed that thein-situsynthesis of BMO-BC complex had a certain removal effect on As (III) at different initial heavy metal concentrations. Its adsorption performance was affected by the presence of biochar particles and manganese dioxide in the reaction system and the manganese oxidation ability of microbial strain MnB1. (v) When the initial concentrations of As (III) were 0-10.0 mg/L, the isothermal adsorption of As (III) on BMO-BC were described in accordance with Langmuir model.

    国产午夜精品论理片| 国产高清激情床上av| 婷婷六月久久综合丁香| 一夜夜www| 三级毛片av免费| 精品久久久久久久久久免费视频| 国产精品亚洲一级av第二区| 成人三级黄色视频| 两个人视频免费观看高清| 亚洲人成伊人成综合网2020| 可以在线观看毛片的网站| 国产精品98久久久久久宅男小说| 久久99热这里只有精品18| 天美传媒精品一区二区| 美女高潮的动态| 在线国产一区二区在线| 亚洲真实伦在线观看| 少妇的逼好多水| 久久天躁狠狠躁夜夜2o2o| 又爽又黄无遮挡网站| 波多野结衣巨乳人妻| 国产高清视频在线播放一区| 国产精品日韩av在线免费观看| 国产精品嫩草影院av在线观看 | 在线免费观看不下载黄p国产 | 一区二区三区高清视频在线| 哪里可以看免费的av片| 亚洲内射少妇av| 日本黄大片高清| 免费av毛片视频| 亚洲aⅴ乱码一区二区在线播放| 亚洲成a人片在线一区二区| 丁香六月欧美| 国产精品久久久久久亚洲av鲁大| 精品久久久久久久久av| 无人区码免费观看不卡| 欧美激情国产日韩精品一区| 草草在线视频免费看| 91久久精品国产一区二区成人| 精品午夜福利视频在线观看一区| 久久久久久久久久成人| 国产一区二区在线观看日韩| 久久午夜福利片| 精品久久久久久成人av| 亚洲色图av天堂| 久久精品久久久久久噜噜老黄 | 国产精品久久久久久久久免 | 丰满乱子伦码专区| 亚洲一区高清亚洲精品| 99久久九九国产精品国产免费| 精华霜和精华液先用哪个| 我要看日韩黄色一级片| 国产v大片淫在线免费观看| 国产午夜精品论理片| 自拍偷自拍亚洲精品老妇| 亚洲无线在线观看| 中出人妻视频一区二区| 国产精品亚洲一级av第二区| 国产黄a三级三级三级人| 日韩亚洲欧美综合| 久久久久久久午夜电影| 日韩 亚洲 欧美在线| 高潮久久久久久久久久久不卡| 日韩中文字幕欧美一区二区| 91麻豆精品激情在线观看国产| 十八禁人妻一区二区| 国产色爽女视频免费观看| 动漫黄色视频在线观看| 国产一区二区三区视频了| 一区二区三区激情视频| 免费看光身美女| 国产av麻豆久久久久久久| 夜夜躁狠狠躁天天躁| 天堂网av新在线| 国产一区二区三区在线臀色熟女| 午夜老司机福利剧场| 亚洲欧美激情综合另类| 日本一本二区三区精品| 两性午夜刺激爽爽歪歪视频在线观看| 亚洲成人免费电影在线观看| 久久久久亚洲av毛片大全| 黄片小视频在线播放| 日韩av在线大香蕉| 老司机午夜福利在线观看视频| 亚洲中文日韩欧美视频| 欧美最新免费一区二区三区 | 91av网一区二区| АⅤ资源中文在线天堂| 18美女黄网站色大片免费观看| 老司机午夜福利在线观看视频| 精品久久久久久久人妻蜜臀av| 黄色日韩在线| 国产免费一级a男人的天堂| 亚洲精品成人久久久久久| 色哟哟·www| 美女cb高潮喷水在线观看| 蜜桃久久精品国产亚洲av| 一本精品99久久精品77| 脱女人内裤的视频| a在线观看视频网站| 国产成人欧美在线观看| 在线观看免费视频日本深夜| 亚洲精品日韩av片在线观看| 国产一区二区三区在线臀色熟女| 91麻豆av在线| 国产精品人妻久久久久久| 免费在线观看影片大全网站| 少妇裸体淫交视频免费看高清| 欧美成人免费av一区二区三区| 国产白丝娇喘喷水9色精品| 国产精品久久久久久精品电影| 性色avwww在线观看| 成人美女网站在线观看视频| 91午夜精品亚洲一区二区三区 | 校园春色视频在线观看| 欧美激情久久久久久爽电影| 国产一区二区在线观看日韩| 国产精华一区二区三区| 怎么达到女性高潮| 久久国产乱子伦精品免费另类| 天美传媒精品一区二区| 男女那种视频在线观看| 亚洲精品一区av在线观看| 亚洲av一区综合| 国产精品久久电影中文字幕| 1000部很黄的大片| 国产高清有码在线观看视频| 国产色婷婷99| 成人三级黄色视频| 男人和女人高潮做爰伦理| 美女被艹到高潮喷水动态| 大型黄色视频在线免费观看| av视频在线观看入口| 日韩欧美在线二视频| 成人特级黄色片久久久久久久| 97超视频在线观看视频| 美女高潮的动态| 99久久九九国产精品国产免费| 亚洲激情在线av| 99精品久久久久人妻精品| 韩国av一区二区三区四区| 国产一区二区在线观看日韩| av女优亚洲男人天堂| 9191精品国产免费久久| 国产蜜桃级精品一区二区三区| 在现免费观看毛片| 成人高潮视频无遮挡免费网站| 亚洲av.av天堂| 别揉我奶头~嗯~啊~动态视频| 免费在线观看日本一区| 又爽又黄无遮挡网站| h日本视频在线播放| 五月玫瑰六月丁香| 91麻豆av在线| 国产精品综合久久久久久久免费| 天美传媒精品一区二区| 高潮久久久久久久久久久不卡| 欧美又色又爽又黄视频| 日本 欧美在线| 人妻丰满熟妇av一区二区三区| 日韩欧美国产一区二区入口| 色播亚洲综合网| 成人美女网站在线观看视频| 精品久久久久久久久亚洲 | 在线播放国产精品三级| 又粗又爽又猛毛片免费看| 午夜亚洲福利在线播放| 免费在线观看日本一区| 五月伊人婷婷丁香| 日韩有码中文字幕| 变态另类成人亚洲欧美熟女| 俄罗斯特黄特色一大片| 精品久久久久久久久久免费视频| www日本黄色视频网| a在线观看视频网站| 波多野结衣巨乳人妻| 欧美bdsm另类| 美女 人体艺术 gogo| 少妇熟女aⅴ在线视频| 宅男免费午夜| 亚洲一区高清亚洲精品| 日本黄大片高清| 免费观看人在逋| 亚洲天堂国产精品一区在线| av天堂在线播放| 亚洲黑人精品在线| 99久久精品一区二区三区| 成人三级黄色视频| bbb黄色大片| 国产精品乱码一区二三区的特点| 少妇的逼好多水| 色综合欧美亚洲国产小说| 欧美日韩亚洲国产一区二区在线观看| 国产精品99久久久久久久久| 啦啦啦观看免费观看视频高清| 老司机深夜福利视频在线观看| 成人毛片a级毛片在线播放| 在线免费观看的www视频| www.www免费av| 级片在线观看| 99视频精品全部免费 在线| 国产欧美日韩一区二区三| 欧美zozozo另类| 精品久久久久久成人av| 亚洲av五月六月丁香网| avwww免费| 久久亚洲真实| 免费黄网站久久成人精品 | 五月玫瑰六月丁香| 国内久久婷婷六月综合欲色啪| 精品人妻偷拍中文字幕| a在线观看视频网站| 国产午夜精品论理片| 欧美黄色片欧美黄色片| 亚洲不卡免费看| 又粗又爽又猛毛片免费看| 天天躁日日操中文字幕| 赤兔流量卡办理| 他把我摸到了高潮在线观看| 女人被狂操c到高潮| 午夜福利在线观看免费完整高清在 | 欧美极品一区二区三区四区| av在线观看视频网站免费| 97热精品久久久久久| 亚洲午夜理论影院| 有码 亚洲区| 亚洲国产精品久久男人天堂| av天堂在线播放| 午夜福利视频1000在线观看| 91狼人影院| 日韩欧美三级三区| 99久国产av精品| 国内少妇人妻偷人精品xxx网站| 男女视频在线观看网站免费| 国产精品野战在线观看| 久久精品国产亚洲av香蕉五月| 可以在线观看的亚洲视频| 亚洲va日本ⅴa欧美va伊人久久| 亚洲18禁久久av| 欧美另类亚洲清纯唯美| 2021天堂中文幕一二区在线观| 国产成人影院久久av| 日韩国内少妇激情av| 国产精品一区二区三区四区久久| 国产精品亚洲一级av第二区| 亚洲人成网站在线播放欧美日韩| 岛国在线免费视频观看| 91在线观看av| 亚洲自偷自拍三级| 久久精品国产亚洲av天美| 亚洲 国产 在线| a在线观看视频网站| 久久精品国产亚洲av涩爱 | 成人美女网站在线观看视频| 免费av毛片视频| 久久精品国产99精品国产亚洲性色| 国产一级毛片七仙女欲春2| 女人十人毛片免费观看3o分钟| 赤兔流量卡办理| 美女高潮喷水抽搐中文字幕| 日本在线视频免费播放| 美女大奶头视频| 欧美xxxx性猛交bbbb| 三级男女做爰猛烈吃奶摸视频| 我要看日韩黄色一级片| 中文字幕高清在线视频| АⅤ资源中文在线天堂| 夜夜躁狠狠躁天天躁| 国产一区二区在线观看日韩| 男人狂女人下面高潮的视频| 国产乱人视频| 精品欧美国产一区二区三| 亚洲av二区三区四区| 嫩草影院精品99| 亚洲av成人精品一区久久| 久久精品夜夜夜夜夜久久蜜豆| 中文字幕精品亚洲无线码一区| 国产亚洲精品久久久久久毛片| 亚洲七黄色美女视频| 欧美高清成人免费视频www| 亚洲自偷自拍三级| 亚洲人成网站高清观看| 丰满人妻一区二区三区视频av| 婷婷丁香在线五月| 精品久久久久久,| 可以在线观看的亚洲视频| 欧美三级亚洲精品| 午夜福利视频1000在线观看| 国产亚洲精品久久久久久毛片| 欧美zozozo另类| 国产精品亚洲美女久久久| 亚洲熟妇熟女久久| 精品久久久久久久久久免费视频| 久久久久九九精品影院| 国产毛片a区久久久久| 欧美性猛交╳xxx乱大交人| 人妻丰满熟妇av一区二区三区| 久久久成人免费电影| 久久草成人影院| 亚洲 国产 在线| 1024手机看黄色片| 色哟哟哟哟哟哟| 亚洲精华国产精华精| 免费看光身美女| 黄色视频,在线免费观看| 丁香六月欧美| 哪里可以看免费的av片| 啦啦啦韩国在线观看视频| 亚洲av.av天堂| 国产成人啪精品午夜网站| 成人三级黄色视频| 极品教师在线视频| 少妇被粗大猛烈的视频| 亚洲精品456在线播放app | 九九热线精品视视频播放| 两人在一起打扑克的视频| 高潮久久久久久久久久久不卡| 18禁黄网站禁片午夜丰满| 九色国产91popny在线| 大型黄色视频在线免费观看| 久久久久久久精品吃奶| 亚洲在线观看片| 国产三级中文精品| 欧美性感艳星| 乱码一卡2卡4卡精品| 亚洲av成人不卡在线观看播放网| 成人特级av手机在线观看| 校园春色视频在线观看| 国产精品综合久久久久久久免费| 国产一区二区激情短视频| 日韩有码中文字幕| 一个人看视频在线观看www免费| 午夜a级毛片| 亚洲国产色片| 757午夜福利合集在线观看| 亚洲国产精品成人综合色| 久久精品影院6| 老司机午夜福利在线观看视频| 99视频精品全部免费 在线| 琪琪午夜伦伦电影理论片6080| 成熟少妇高潮喷水视频| 欧美区成人在线视频| a级毛片免费高清观看在线播放| 亚洲av不卡在线观看| 精品人妻偷拍中文字幕| 成人午夜高清在线视频| 又爽又黄无遮挡网站| 亚洲欧美日韩卡通动漫| 国产单亲对白刺激| 亚洲av五月六月丁香网| 97超视频在线观看视频| 最新在线观看一区二区三区| 麻豆成人av在线观看| 琪琪午夜伦伦电影理论片6080| 亚洲人成网站在线播| 免费在线观看影片大全网站| 嫩草影院新地址| 欧美一级a爱片免费观看看| 国产真实伦视频高清在线观看 | 久久亚洲真实| 精品久久久久久久人妻蜜臀av| 男女下面进入的视频免费午夜| www.www免费av| 在线十欧美十亚洲十日本专区| 一个人免费在线观看电影| 搞女人的毛片| 日日干狠狠操夜夜爽| 黄色配什么色好看| 久久亚洲真实| 亚洲专区国产一区二区| 男人的好看免费观看在线视频| 久久国产精品影院| 高清毛片免费观看视频网站| 成年女人看的毛片在线观看| 国产人妻一区二区三区在| 欧美一区二区精品小视频在线| 麻豆国产av国片精品| 日韩欧美 国产精品| 亚洲男人的天堂狠狠| 色在线成人网| 午夜福利成人在线免费观看| 亚洲片人在线观看| 国产精品永久免费网站| 亚洲,欧美精品.| 亚洲在线自拍视频| 国模一区二区三区四区视频| 免费看光身美女| 成人午夜高清在线视频| 日本成人三级电影网站| 禁无遮挡网站| 12—13女人毛片做爰片一| 日韩有码中文字幕| 亚洲乱码一区二区免费版| 色视频www国产| 亚洲成人精品中文字幕电影| 91麻豆av在线| 亚洲综合色惰| 夜夜躁狠狠躁天天躁| 国产黄a三级三级三级人| 午夜视频国产福利| 观看美女的网站| 国内精品一区二区在线观看| 在线观看午夜福利视频| 1000部很黄的大片| 日本撒尿小便嘘嘘汇集6| 亚洲欧美日韩无卡精品| 一卡2卡三卡四卡精品乱码亚洲| 久久精品国产自在天天线| 欧美国产日韩亚洲一区| 国产精品一区二区三区四区久久| 看黄色毛片网站| 国产精品自产拍在线观看55亚洲| 特级一级黄色大片| 最近最新免费中文字幕在线| 在线天堂最新版资源| 久久九九热精品免费| 老熟妇仑乱视频hdxx| bbb黄色大片| 久久人人精品亚洲av| 女人被狂操c到高潮| 日韩欧美精品v在线| 中文字幕免费在线视频6| www.色视频.com| 久久人妻av系列| 99在线人妻在线中文字幕| 久久久久久久久中文| 亚洲av一区综合| 成年版毛片免费区| 亚洲av免费高清在线观看| 大型黄色视频在线免费观看| 免费看日本二区| 欧美bdsm另类| 99热这里只有是精品50| 90打野战视频偷拍视频| 欧美激情久久久久久爽电影| 国产精华一区二区三区| 男人舔奶头视频| 亚洲第一欧美日韩一区二区三区| 亚洲激情在线av| 欧美最黄视频在线播放免费| 国产一区二区三区在线臀色熟女| 成人国产综合亚洲| 亚洲成av人片免费观看| 国产av在哪里看| 亚洲av电影不卡..在线观看| 亚洲精品色激情综合| 窝窝影院91人妻| av在线天堂中文字幕| 少妇高潮的动态图| 毛片女人毛片| 中文字幕av成人在线电影| 国产69精品久久久久777片| 男女下面进入的视频免费午夜| 老师上课跳d突然被开到最大视频 久久午夜综合久久蜜桃 | 日韩精品中文字幕看吧| 久久久久国内视频| 在线观看av片永久免费下载| 99久国产av精品| 久久精品国产清高在天天线| 赤兔流量卡办理| 69人妻影院| 在线a可以看的网站| 99在线视频只有这里精品首页| 午夜福利在线在线| 亚洲久久久久久中文字幕| 亚洲精品色激情综合| 人人妻人人看人人澡| av视频在线观看入口| 国产精品久久久久久久电影| 亚洲人与动物交配视频| 久久精品国产自在天天线| av在线老鸭窝| 淫秽高清视频在线观看| 国产白丝娇喘喷水9色精品| 亚洲最大成人手机在线| 国产野战对白在线观看| 天堂影院成人在线观看| 国产精品一区二区三区四区久久| 亚洲一区二区三区不卡视频| 性插视频无遮挡在线免费观看| 麻豆久久精品国产亚洲av| 麻豆av噜噜一区二区三区| 日韩中字成人| 国产精品一区二区免费欧美| 俄罗斯特黄特色一大片| 女同久久另类99精品国产91| 亚洲人成电影免费在线| 亚洲精品成人久久久久久| 十八禁国产超污无遮挡网站| 欧美性感艳星| 亚洲成人免费电影在线观看| 欧美色欧美亚洲另类二区| 国产主播在线观看一区二区| 丁香六月欧美| 亚洲国产精品成人综合色| 人妻夜夜爽99麻豆av| 欧美中文日本在线观看视频| 丰满人妻一区二区三区视频av| 午夜日韩欧美国产| 一区二区三区免费毛片| 此物有八面人人有两片| 亚洲国产精品久久男人天堂| 国产精品日韩av在线免费观看| 日韩精品中文字幕看吧| 午夜精品久久久久久毛片777| 亚洲欧美日韩无卡精品| 国产成人a区在线观看| 最近视频中文字幕2019在线8| 亚洲经典国产精华液单 | 精品久久久久久久久亚洲 | 欧美一区二区精品小视频在线| 中出人妻视频一区二区| 亚洲av成人av| 国内精品一区二区在线观看| 最近在线观看免费完整版| 亚洲国产精品999在线| 国产精品一区二区免费欧美| 少妇裸体淫交视频免费看高清| 在线天堂最新版资源| 亚洲成a人片在线一区二区| 国产欧美日韩一区二区三| 中文字幕av在线有码专区| 欧美成人a在线观看| 又粗又爽又猛毛片免费看| 国产av在哪里看| 好男人在线观看高清免费视频| 日本黄色视频三级网站网址| 毛片一级片免费看久久久久 | 国产综合懂色| 日韩欧美三级三区| 亚洲人成网站高清观看| 国产高清视频在线观看网站| 中文字幕久久专区| 久久久久久久午夜电影| 亚洲成av人片在线播放无| 国产精品精品国产色婷婷| 亚洲,欧美,日韩| 91在线精品国自产拍蜜月| 亚洲色图av天堂| 日韩高清综合在线| 午夜福利在线观看免费完整高清在 | 男人的好看免费观看在线视频| 午夜福利在线观看免费完整高清在 | 小蜜桃在线观看免费完整版高清| 亚洲五月天丁香| 国产精品久久久久久亚洲av鲁大| 国产在视频线在精品| 深爱激情五月婷婷| 亚洲中文字幕一区二区三区有码在线看| 欧美3d第一页| 天堂动漫精品| 日本熟妇午夜| 日韩有码中文字幕| 日韩欧美一区二区三区在线观看| 国产亚洲精品av在线| 高清毛片免费观看视频网站| 日韩欧美精品v在线| 亚洲欧美日韩高清在线视频| 欧美成人性av电影在线观看| 日本免费一区二区三区高清不卡| 亚洲第一电影网av| 深爱激情五月婷婷| av在线蜜桃| 免费黄网站久久成人精品 | 亚洲精品一卡2卡三卡4卡5卡| bbb黄色大片| 久久久久久久久大av| 国产伦在线观看视频一区| 久久午夜亚洲精品久久| 少妇丰满av| 免费av观看视频| 国产精华一区二区三区| av国产免费在线观看| 99久久精品一区二区三区| 欧美黄色片欧美黄色片| 国产成人av教育| 久久久久久久久大av| 国产精品亚洲美女久久久| 在现免费观看毛片| 亚洲片人在线观看| 国产精品不卡视频一区二区 | 99国产极品粉嫩在线观看| 十八禁国产超污无遮挡网站| 岛国在线免费视频观看| 欧美+亚洲+日韩+国产| 国产 一区 欧美 日韩| 久久国产乱子免费精品| 日韩大尺度精品在线看网址| 国产精品久久久久久人妻精品电影| 此物有八面人人有两片| 国产高清三级在线| 久久久久久久精品吃奶| 人人妻,人人澡人人爽秒播| 日本一本二区三区精品| 欧美在线一区亚洲| 91午夜精品亚洲一区二区三区 | 身体一侧抽搐| 亚洲美女搞黄在线观看 | 国产精品日韩av在线免费观看| 欧美区成人在线视频| 国产v大片淫在线免费观看| 丰满乱子伦码专区| 久久精品91蜜桃| 亚洲男人的天堂狠狠| 99国产综合亚洲精品| 日本黄大片高清| 色尼玛亚洲综合影院| 国产黄色小视频在线观看| 国产乱人视频| 久久久久久久亚洲中文字幕 | 成人毛片a级毛片在线播放| 又爽又黄a免费视频| 国产高清有码在线观看视频| 亚洲精品在线观看二区| 啦啦啦观看免费观看视频高清|