Experimental Method and Application of Rapid and Continuous Extraction of Reduced Inorganic Sulfur from Sediments
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摘要:
还原性无机硫是沉积物硫中最活跃的部分,其含量变化控制沉积物中铁、磷及重金属等元素的地球化学行为,在地质过程和环境污染方面都具有至关重要的影响。化学连续提取法是目前沉积物中硫形态提取基本方法,但常用的冷扩散法处理单个样品耗时长,难以实现对大批量样品的快速连续提取。为实现快速、准确地测定沉积物样品各形态还原性无机硫的含量,本文采用热蒸馏法,改进基于前人的三步提取过程,通过优化实验装置预先制备实验所需的二氯化铬溶液,实现了样品还原性无机硫形态的快速连续提取;以过氧化氢为氧化剂,将提取的各形态硫氧化为$\mathrm{SO}_4^{2-}$后采用离子色谱进行检测。选取三峡库区沉积物样品进行重复实验检验,得到提取酸挥发性硫、黄铁矿硫、元素硫的标准偏差(RSD,n=3)分别为5.26%、1.22%和3.09%,重复性较好。进一步对酸挥发性硫、黄铁矿硫、元素硫的加标回收率进行测定,得到这三种硫形态的回收率分别为92.8%、93.6%、94.1%。本实验方法采用的热蒸馏法对单个硫形态提取时间为1.5h,用时较短,玻璃装置连接便捷、操作简单,分析检测准确度好,实现了一套装置对沉积物还原性无机硫形态的连续提取,可适用于大批量样品的硫形态快速提取与检测。
要点(1) 所设计的实验装置实现了对各形态还原性无机硫的连续提取。
(2) 提取出的各形态还原性无机硫采用过氧化氢氧化为SO42-后,实现了离子色谱的统一检测。
(3) 三峡库区沉积物的研究显示,库区硫污染程度较低。
HIGHLIGHTS(1) Continuous extraction of reduced inorganic sulfur from sediments was achieved.
(2) All forms of reduced inorganic sulfur were oxidized to SO42- using H2O2 and then detected by ion chromatography.
(3) Three Gorges Reservoir sediments show low reduced inorganic sulfur content.
Abstract:BACKGROUNDSulfur is an active element with multiple chemical forms, which plays a vital role in the regulation of redox chemistry. Reduced inorganic sulfur (RIS) including acid volatile sulfur (AVS), elemental sulfur (ES) and pyrite sulfur (CRS) is the most active part of sulfur species in sediments and plays an important role in controlling the geochemical behavior of iron, phosphorus and heavy metals in sediments. Separation and determination of reduced inorganic sulfur in anoxic sediments are critical to ecological and geological studies of sulfur cycles.
Both distillation and diffusion methods can be effectively used to separate AVS, ES, and CRS in sediments. However, the current methods for extracting sulfur species are difficult to adapt to the large number of samples in geological and environmental research. Due to the reaction time, requirements of 24h for single sulfur species in the diffusion method limits the number of samples that can be processed on a timely basis. This limitation presents a problem for analyzing fresh anoxic sediment samples which have to be processed immediately to minimize the risk of sulfide re-oxidation. The detection method has the disadvantages of having a cumbersome testing process, long analysis time, and easy loss of sulfur components.
OBJECTIVESTo achieve efficient and continuous determination of reduced inorganic sulfur forms in bulk sediment samples.
METHODSThe method used in this experiment was improved based on the thermal distillation method, which was used to continuously extract the reduced inorganic sulfur from sediments. The reaction flask used in the experiment was a three-head round-bottom flask. A nitrogen flushing pipe, a condenser tube and two injection tubes were connected to each of the small necks. For the AVS procedure, 1.00g sediment sample reacted with 10mL of 6mol/L HCl under nitrogen gas at an elevated temperature (90℃) to convert reduced sulfur species into hydrogen sulfide which was subsequently carried by a nitrogen gas stream into a trap. For the CRS procedure, 20mL of CrCl2 solution was added to the sediment in the distillation flask after the AVS procedure, and 10mL of 6mol/L HCl was immediately placed in the flask at an elevated temperature (90℃), flushed with nitrogen. For the ES procedure, 20mL DMF were poured into the sample flask which contained acid and CrCl2 solutions from the previous procedure. 20mL of CrCl2 solution and 10mL of 6mol/L HCl were injected into the flask, and the reaction was allowed to take place at 90℃ purging with nitrogen. During the entire distillation process, H2S gas was absorbed by NaOH solution, and then oxidized by H2O2 to
$\mathrm{SO}_4^{2-}$ . The concentrations of$\mathrm{SO}_4^{2-}$ were obtained by ion chromatography.RESULTSRepeatability experiments (n=3) were conducted on sediment samples from the Three Gorges Reservoir area and the mean values of acid volatile sulfur, elemental sulfur and pyrite sulfur were obtained as 0.19, 0.37 and 3.10μmol/g, respectively. The relative standard deviations (RSD) of the experimental results were 5.26%, 1.22% and 3.09%, respectively. In order to test the effectiveness of the distillation procedures, Na2S·9H2O, pyrite and S were added in the sediment to reveal the corresponding standard recoveries. An average of 92.8% of the added Na2S·9H2O was recovered by the AVS diffusion method. An average of 93.6% of the added pyrite was recovered by the CRS diffusion method. An average of 94.1% of the added elemental sulfur was recovered by the ES diffusion method. In the literature, recovery of AVS by the improved diffusion method ranged from 82.01% to 108.71%, and recovery of ES ranged from 92.25% to 98.08% (n=3), respectively.
The modified apparatus presented in this paper was an economic version which uses rubber and glass parts. The method provided the advantages of lower sample weighing, and simple operation. Compared with the diffusion method (24h), the extraction time for individual sulfur forms by our distillation method was just 1.5h. The recoveries achieved by the method are comparable to those reported for earlier methods. In addition, the results are more like the data on reduced inorganic sulfur content obtained by Hongbin Yin after measuring sediment samples from Taihu Lake using the modified cold diffusion method, indicating that the method designed in this study has a high degree of confidence.
Geochemical processes of sulfur in river aquatic systems play a crucial role in environmental evolution. In this study, the distributions and seasonal variation of reduced inorganic sulfur (RIS) in the Three Gorges Reservoir area surface sediments were investigated. Surface sediment samples were collected from 8 points in the section from Yunyang to Zigui in the Three Gorges Reservoir area in August and December 2017. The result showed that the AVS and ES contents were higher in summer than in winter, and the trend of RIS in the section from Yunyang to Zigui was roughly decreasing, with obvious seasonal and spatial changes. Low sulfur pollution in the Three Gorges Reservoir area was observed.
CONCLUSIONSThe improved thermal distillation method and apparatus in this study have significant advantages in the extraction efficiency of reduced inorganic sulfur from sediments. The extraction time of this study for individual sulfur form is 1.5h, less than the diffusion method. The established analytical method has good precision and accuracy, which is suitable for investigation studies with large numbers of samples such as environmental research and geological surveys.
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锑(Sb)是一种重要的战略金属,应用领域包括阻燃塑料、缩聚催化剂、铅酸电池、玻璃、橡胶、颜料、陶瓷、半导体等[1-2]。同时,锑也是一种对动植物有害的非必需类金属,其毒性、迁移性受到锑存在形式的影响[3]。环境中锑主要存在形式为Sb(OH)3和Sb(OH)−6,其中三价锑Sb(Ⅲ)的毒性明显高于五价锑Sb(Ⅴ)[4]。世界卫生组织规定饮用水中锑的最大允许浓度为20μg/L,中国规定饮用水中的最大允许浓度为5μg/L,锑及含锑化合物已被欧盟(EU)和美国环境保护署(USEPA)列为新兴污染物或优先关注的污染物[5]。中国锑资源丰富,锑矿主要集中在广西、湖南、云南和贵州地区[6-7]。中国也是锑资源开采大国,锑产能约占全球的78%[8]。锑矿的大量开采和冶炼,产生的尾矿废渣和矿山废石中锑含量较高。同时,有色金属冶炼、燃烧化石燃料等活动也会产生大量含锑废物,经雨水冲刷和地表径流等因素进入土壤[9]。例如某射击场和燃煤电厂附近的土壤中锑含量高达67.48mg/kg和39.29mg/kg[10-11],造成了严重的污染。地表土壤中的锑除直接污染地表、地下水以外,还可能经由植物根部吸收富集,威胁动物和人类健康[12]。因此,厘清锑在土壤中的吸附、迁移行为对准确预测锑的环境风险具有重要意义。
进入土壤的锑可能被吸附、解吸,甚至发生氧化还原反应,自然状况下锑可以通过与金属氢氧化物发生吸附或者共沉淀形成稳定的次生锑矿物[13],而锑矿物中的锑也可转变为溶解态,扩散至周边环境乃至地下水中。土壤中吸附锑的活性成分主要为铁、铝和锰氧化物和黏土矿物等,其中广泛存在于土壤和沉积物中的铁氧化物[14],如针铁矿、赤铁矿和水铁矿等,对锑的固定占比可达40%~75%[15]。有研究表明,锑在铁氧化物表面的吸附、沉淀行为与矿物晶面的暴露情况及其浓度有复杂依赖关系[16],可在氧化铁表面形成多种配位构型的内球配合物[17],基于零价铁的锑污染土壤修复技术也有报道[18]。锰氧化物是自然界中常见的天然氧化剂,可通过氧化和吸附机制在降低锑的毒性和影响锑的迁移行为方面发挥至关重要的作用[19],如有研究报道了天然存在的锰氧化物会降低锑的流动性和生物利用度[20]。氧化锰不同的暴露晶面对锑的吸附行为也有差异,如Sb(Ⅲ)优先吸附于α-MnO2的{310}、γ-MnO2(斜方锰矿)的{131}和δ-MnO2的{111}晶面[21]。铝氧化物和黏土材料虽然对锑的吸附量较低,但自然界中氧化铝和黏土矿物相对含量可能较高,对锑的影响也不可忽视[22]。研究发现Sb(Ⅴ)在γ-Al2O3可形成外配球络合物[23],膨润土对Sb(Ⅲ)和Sb(Ⅴ)的最大吸附量分别为370~555μg/g和270~500μg/g[24]。上述材料通过改性可提高对锑的吸附能力,因而可以构建锑污染的修复材料[25]。尽管目前已有文献关注天然矿物对锑的吸附、解吸行为[26-27],但锑在天然矿物界面处形态的原位表征、其形态与锑浓度的相关性仍未见报道,了解这些基本信息将有助于深入了解锑的地球化学循环及环境风险。
因此,为探究进入土壤中不同价态锑的吸附迁移行为,有必要对土壤中典型矿物吸附锑的性能及吸附机制进行比较与研究。本文基于土壤的主要成分及相关文献中已证实的对锑的吸附迁移行为有显著影响的组分,选择了土壤中代表性的5种金属氧化物(赤铁矿、针铁矿、水铁矿、斜方锰矿、氧化铝)和一种黏土矿物(高岭石),系统地比较了这6类矿物对Sb(Ⅲ)和Sb(Ⅴ)的吸附性能,获得吸附速率、吸附容量、pH值对吸附的影响等热力学、动力学参数,并结合拉曼光谱对锑在矿物表面的吸附、沉积行为进行原位表征。通过分析吸附机制,总结了上述土壤中典型矿物对锑环境迁移行为的影响,研究结果可为土壤中锑污染风险预警及阻控提供参考。
1. 实验部分
1.1 材料及表征
为尽可能地反映实际土壤成分的特征,本研究除水铁矿外,其他材料均直接采用商品化的矿物材料,包括:斜方锰矿(γ-MnO2,90%,上海麦克林生化科技有限公司);赤铁矿(α-Fe2O3,99.8%,上海麦克林生化科技有限公司);针铁矿(FeHO2,99%,上海贤鼎生物科技有限公司);氧化铝(α-Al2O3,99.99%,艾览化工科技有限公司);高岭石(A12O3·2SiO2·2H2O,分析纯,上海麦克林生化科技有限公司)。水铁矿由于稳定性较差,为保证实际存在形态的一致性,采用实验室方法合成。合成方法[28]如下:配制0.2mol/L硝酸铁(分析纯,国药集团化学试剂有限公司)溶液,在不断搅拌情况下滴加浓氨水至溶液pH=7.0,再搅拌30min。离心、超声洗涤3次,真空干燥12h。
采用X射线衍射仪(XRD,SmartLab SE,日本Rigaku公司)和比表面积测试仪(BET,ASAP2460,美国麦克仪器公司)对材料进行表征。样品处理如下:将赤铁矿、针铁矿、水铁矿、斜方锰矿、氧化铝、高岭石于真空烘箱60℃干燥12h后手动研磨后进行测试。
采用Zeta电位测试(ZEN3690,英国Malvern公司)表征材料的表面电位。样品处理如下:将材料超声分散后,采用盐酸和氢氧化钠将分散液调至不同pH值,取上清液测试样品的Zeta电位。
采用电感耦合等离子体发射光谱仪(ICP-OES,EXPEC6000,杭州谱育科技发展有限公司)测定溶液中锑浓度。仪器工作条件:功率1150W,蠕动泵转速50r/min,辅助气流速0.6L/min,雾化器气体流速0.5L/min(转子流量计测量),冲洗时间30s,积分时间15s,重复次数3次。锑元素的特征谱线为:206.8、231.1、259.8nm。
采用拉曼光谱仪(Raman,QEPRO,蔚海光学仪器(上海)有限公司)对界面吸附态锑进行原位表征。测试方法及仪器条件如下:取吸附后的矿物分散液10μL滴加至玻片,直接进行拉曼光谱测试。激光波长780nm,激光功率100mW,积分时间10s,积分次数10次,光谱分辨率2cm−1。拉曼测试时每个样品至少随机选取10个不同的位置进行光谱采集,计算平均光谱进行后续分析。
1.2 Sb(Ⅲ)/Sb(Ⅴ)的吸附热力学实验
将焦锑酸钾、酒石酸锑钾溶解配制成1000mg/L的储备溶液,实验前按照一定比例稀释到目标浓度。进行吸附实验前,先使用0.1mol/L盐酸或0.1mol/L氢氧化钠将10mL不同浓度的Sb(Ⅲ)和Sb(Ⅴ)初始溶液pH调节至7.0,同时加入硝酸钾控制离子强度为10mmol/L。向溶液中加入一定量的矿物材料,并在25℃下振荡吸附24h。取上层清液通过0.22μm水系滤头过滤,酸化,稀释10倍后,使用ICP-OES测定吸附后锑的浓度,计算吸附量qe(mg/g)。土壤铁锰氧化物和黏土矿物的用量分别为:赤铁矿10mg、针铁矿10mg、水铁矿5mg、氧化铝20mg、斜方锰矿10mg、高岭石50mg。实验中每组样品均平行测定3次,取平均值进行分析。
1.3 Sb(Ⅲ)/Sb(Ⅴ)的吸附动力学实验
取30mL浓度为15mg/L的Sb(Ⅲ)和Sb(Ⅴ)溶液,pH调节至7.0,加入硝酸钾保持离子强度为10mmol/L。加入一定量矿物后于25℃下振荡吸附,在吸附不同时间后,取上层清液通过0.22μm水系滤头过滤,酸化、稀释,ICP-OES检测。土壤铁锰氧化物和黏土矿物的用量分别为:赤铁矿60mg、针铁矿30mg、水铁矿7.5mg、氧化铝150mg、斜方锰矿30mg、高岭石600mg。实验中每组样品均平行测定3次,取平均值进行分析。
1.4 pH值对Sb(Ⅲ)/Sb(Ⅴ)吸附的影响实验
分别将30mL浓度为15mg/L的Sb(Ⅲ)和Sb(Ⅴ)溶液的初始溶液pH调节为4.0、7.0、9.0,加入硝酸钾保持离子强度为10mmol/L。加入一定量矿物材料后,于25℃下振荡吸附。吸附24h后,取上层清液通过0.22μm水系滤头过滤,酸化、稀释,ICP-OES检测。矿物用量同1.2节。实验中每组样品均平行测定3次,计算平均值进行分析。
2. 结果与讨论
2.1 六种矿物材料表征
为了解矿物的晶型及物相类型,采用X射线衍射谱分析矿物,其谱图见图1。6种矿物的XRD谱图与标准卡片对照,除水铁矿无明显晶型以外,另外5种矿物的XRD谱图与矿物标准谱图吻合较好,且无其他杂相;水铁矿为无定型矿物,其XRD谱图与文献报道结果[29]一致。矿物的比表面积采用Brunauer-Emmett-Teller法(BET)进行测定,分别测定了6种材料的氮气吸脱附曲线,结果如图2所示。经计算,6种矿物材料赤铁矿、针铁矿、斜方锰矿、氧化铝、高岭石和水铁矿的比表面积分别为6.6、18.9、32.3、6.1、10.5、335.6m2/g。其中,赤铁矿、针铁矿、斜方锰矿、氧化铝、高岭石的氮气吸附-解吸等温线符合Ⅳ类型吸附等温线,说明这5种材料具有介孔结构(孔直径为2~50nm);水铁矿的氮气吸附-解吸等温线符合Ⅰ类型吸附等温线,说明水铁矿具有微孔结构(孔直径<2nm)。
2.2 六种矿物材料对锑的吸附动力学研究
中性条件下6种矿物材料对Sb(Ⅲ)/Sb(Ⅴ)的吸附动力学如图3所示,吸附数据拟合均更符合准二级动力学模型(表1),表明化学吸附是主要的速率控制步骤。Sb(Ⅲ)和Sb(Ⅴ)在吸附初始阶段即前2h内吸附速率较快;随着吸附时间进一步延长,矿物表面的活性吸附位点逐渐饱和,吸附速率在2~6h内逐渐下降;除斜方锰矿吸附Sb(Ⅲ)外,其他材料均在24h左右达到吸附平衡。斜方锰矿吸附Sb(Ⅲ)在吸附初期(约5min)迅速达到较高的吸附量,该过程可能与其对Sb(Ⅲ)的氧化作用有关,反应方程式如以下(1)和(2)所示,氧化反应[30]以及生成Sb(Ⅴ)的吸附共同作用导致前期吸附速率较快[31];在斜方锰矿氧化Sb(Ⅲ)的过程中,可能破坏其表面结构,导致少部分吸附态锑的溶出[25],因此20min后Sb(Ⅲ)的吸附量有一定程度地下降。随吸附时间的继续延长,Sb(Ⅲ)的吸附逐步达到平衡。
表 1 Sb(Ⅲ)和Sb(Ⅴ)的吸附动力学拟合参数Table 1. Fitting parameters of adsorption kinetics for Sb(Ⅲ) and Sb(Ⅴ)矿物材料 Sb(Ⅲ)准一级动力学 Sb(Ⅲ)准二级动力学 Sb(Ⅴ)准一级动力学 Sb(Ⅴ)准二级动力学 K1
(h−1)qe
(mg/g)R2 K2
[g/(mg·h)]qe
(mg/g)R2 K1
(h−1)qe
(mg/g)R2 K2
[g/(mg·h)]qe
(mg/g)R2 赤铁矿 2.58 7.35 0.750 0.88 7.45 0.911 1.15 1.05 0.721 1.52 1.13 0.913 针铁矿 0.53 7.83 0.896 0.12 8.22 0.986 1.75 2.74 0.721 1.05 2.86 0.924 水铁矿 4.74 33.7 0.645 0.40 34.4 0.957 3.33 24.1 0.946 0.33 24.8 0.999 斜方锰矿 82.1 7.03 0.716 41.9 7.22 0.940 0.75 4.90 0.832 0.20 5.30 0.921 氧化铝 6.58 0.71 0.958 15.5 0.73 0.976 4.49 0.59 0.631 16.1 0.61 0.933 高岭石 6.45 0.08 0.927 132.8 0.08 0.973 0.34 0.09 0.894 9.17 0.06 0.939 $$ \mathrm{MnO}_{ \mathrm{2}} \mathrm{+Sb(OH)}_{ \mathrm{3}} \mathrm{+H}^{ \mathrm+} \mathrm{+H}_{ \mathrm{2}} \mathrm{O\rightarrow Mn}^{ \mathrm{2+}} \mathrm{+Sb(OH)}_{ \mathrm{6}}^{ \mathrm-} $$ (1) $$ \mathrm{2MnO}_{ \mathrm{2}} \mathrm{+Sb(OH)}_{ \mathrm{3}} \mathrm{+5H}^{ \mathrm+}\rightarrow \mathrm{2Mn}^{ \mathrm{3+}} \mathrm{+Sb(OH)}_{ \mathrm{6}}^{ \mathrm-} \mathrm{+H}_{ \mathrm{2}} \mathrm{O} $$ (2) 2.3 六种矿物对锑的吸附等温线
为了比较6种矿物材料对锑的吸附能力,分别测得中性条件下Sb(Ⅲ)/Sb(Ⅴ)在6种矿物表面吸附的吸附等温线,结果如图4所示,随着Sb(Ⅲ)/Sb(Ⅴ)初始浓度的增加,矿物对锑的吸附量增加。分别采用Langmuir和Freundlich等温线模型对吸附等温线进行了拟合,相关拟合参数列于表2。结果表明,Freundlich模型拟合结果的R2值均大于Langmuir模型,表明锑在上述6种矿物表面主要发生多层吸附。Freundlich系数(KF)反映了吸附质在吸附剂表面的吸附程度,KF越高,表示吸附越有效,因此对于矿物吸附锑而言,铁氧化物和锰氧化物对锑的KF较大,表明上述材料与锑的亲和性较强[32]。
表 2 Sb(Ⅲ)和Sb(Ⅴ)的吸附等温线拟合参数Table 2. Fitting parameters of adsorption isotherms of Sb(Ⅲ) and Sb(Ⅴ)材料 Sb(Ⅲ)-Langmuir Sb(Ⅲ)-Freundlich Sb(Ⅴ)-Langmuir Sb(Ⅴ)-Freundlich KL
(L/mg)qm
(mg/g)R2 n KF
[(mg/g)(mg/L)−1/n]R2 KL
(L/mg)qm
(mg/g)R2 n KF
[(mg/g)(mg/L)−1/n]R2 赤铁矿 0.48 5.13 0.961 2.90 1.90 0.996 0.11 3.70 0.925 2.43 0.70 0.997 针铁矿 0.21 13.30 0.834 2.22 3.05 0.997 0.14 5.67 0.987 2.79 1.30 0.994 水铁矿 1.01 101.4 0.980 2.09 45.3 0.979 1.00 55.9 0.789 4.62 31.7 0.987 斜方锰矿 0.15 16.52 0.964 2.19 3.19 0.993 0.76 7.58 0.950 4.62 3.56 0.995 氧化铝 0.08 1.66 0.961 1.84 0.20 0.993 0.10 1.69 0.871 2.75 0.36 0.983 高岭石 0.21 0.27 0.967 2.96 0.08 0.957 0.12 0.51 0.990 2.27 0.09 0.921 6种矿物对不同价态锑的吸附能力不同,整体而言,同种矿物材料对Sb(Ⅲ)的吸附容量大于该矿物对Sb(Ⅴ)的吸附容量,表明进入土壤的Sb(Ⅲ)相较于Sb(Ⅴ)更容易被土壤矿物吸附固定。对比吸附容量,单位质量土壤矿物对Sb(Ⅲ)和Sb(Ⅴ)的最大吸附容量(mg/g)分别为:水铁矿(101.4、55.9)>斜方锰矿(16.52、7.58)>针铁矿(13.30、5.67)>赤铁矿(5.13、3.70)>氧化铝(1.66、1.69)>高岭石(0.27、0.51)。土壤中的铁氧化物一般具有较大的比表面积、高孔隙率和表面电荷高等特点,而且对锑有较强的化学亲和力,因此是控制锑元素迁移和生物利用度的关键成分[33]。相比于晶型的针铁矿和赤铁矿,水铁矿的比表面积更大,吸附活性位点更多,因此对锑的吸附能力更强[34]。土壤中锰氧化物尽管含量较低,但由于锰具有丰富的价态和较强的氧化能力,因此可介导锑等变价金属发生氧化还原反应[21]。此外,锰氧化物对锑的亲和作用也会参与锑的吸附固定,因此锰氧化物在控制锑的迁移和形态转化行为方面发挥着重要的作用。斜方锰矿对Sb(Ⅲ)的吸附量大于Sb(Ⅴ),说明在介导Sb(Ⅲ)的氧化过程中,斜方锰矿自身的晶体结构可能发生改变,从而提供更多的活性位点,使得Sb(Ⅲ)的吸附量提高[21]。氧化铝和黏土矿物高岭石对锑的吸附量较低,原因是这类矿物对锑的化学亲和性较弱[22],同时比表面积也较小。但由于某些土壤中,如岩石矿床风化沉积土壤、河流沉积土壤,氧化铝和高岭石的含量可能远高于铁氧化物或锰氧化物,因此对于这类情况,上述矿物对土壤中锑迁移行为的影响也不容忽视。
2.4 pH值对六种矿物材料吸附Sb(Ⅲ)/Sb(Ⅴ)行为的影响
为了探究可能的吸附机制,对pH值对矿物材料吸附锑性能的影响进行了实验,结果如图5所示。6种矿物材料对Sb(Ⅲ)的吸附在实验的pH条件下吸附量变化不大(0.3%~14%),而随着pH值的升高,6种矿物材料对Sb(Ⅴ)的吸附量均有所下降(24%~78%),表明偏碱性不利于Sb(Ⅴ)的吸附。相较Sb(Ⅲ)而言,Sb(Ⅴ)的吸附量下降程度更大。矿物材料的Zeta电位表征结果(图5c)显示,赤铁矿、针铁矿、水铁矿、斜方锰矿、氧化铝、高岭石的等电点分别为3.1、4.4、7.2、4.5、7.8和1.6;根据锑在水溶液中的形态分布曲线,实验条件下Sb(Ⅲ)、Sb(Ⅴ)主要存在形态分别为Sb(OH)3和Sb(OH)6−。由于Sb(Ⅲ)主要以分子形式存在,因此受静电吸附作用的影响较小,说明矿物对Sb(Ⅲ)的吸附主要依靠化学吸附等机制;对于Sb(Ⅴ),尽管静电吸附作用有一定的贡献,例如酸性条件下,水铁矿、针铁矿、斜方锰矿、氧化铝带正电荷,有利于带负电的Sb(Ⅴ)的吸附,但整体而言,静电吸附的贡献有限,矿物对Sb(Ⅴ)的吸附主要通过化学吸附等形式完成。类似的现象也在砷、镉等重金属的吸附中观测到[35-36]。由于高岭石在研究的pH范围内均带负电荷,不利于Sb(Ⅴ)的吸附,这与观测到的低吸附量一致。
2.5 Sb(Ⅲ)/Sb(Ⅴ)在矿物表面吸附沉积后拉曼检测
有文献报道,当平衡浓度较低时,土壤矿物对锑吸附主要通过表面化学吸附,而随着表面浓度的增加,超过饱和浓度后,锑可能在矿物表面发生沉积现象[37]。为了验证上述现象,采集了更高平衡浓度下锑的吸附等温线,结果如图6所示。结果表明,随着平衡浓度的进一步增大,矿物对锑的吸附容量会进一步增大;吸附等温线拟合数据表明,锑在矿物表面吸附符合Freundlich多层吸附模型;特别是对于Sb(Ⅲ)吸附于针铁矿和赤铁矿表面,还观测到吸附量激增的现象,推测发生了表面沉积现象。
由于Sb(Ⅲ)沉积后可能以Sb2O3形式存在,拉曼光谱是一种分子指纹光谱,不仅对矿物材料的结构敏感,同时锑的氧化物也有特征拉曼谱峰,非常适合于这类表面沉积现象的原位表征,因此本实验采用拉曼光谱对吸附锑后的矿物进行表征,结果如图7和图8所示。可见除水铁矿外,其他5种矿物具有明显的特征峰。结合已有相关文献报道,对获得的特征拉曼峰的归属进行了归纳,相应的峰位及归属列于表3。对于高浓度的Sb(Ⅴ)吸附后的矿物材料,并没有获得Sb(Ⅴ)氧化物Sb2O5的特征峰,表明并没有明显的沉积现象出现,主要以吸附作用为主;而对于Sb(Ⅲ),如图8所示,出现了明显的Sb2O3特征峰。位于190cm−1和452cm−1的拉曼峰可归属于Sb—O—Sb间的弯曲振动,而256、357、374和715cm−1的拉曼峰则可归属于Sb—O—Sb间的伸缩振动[38]。上述特征峰与矿物立方晶型α-Sb2O3的特征谱峰一致,表明表面沉积主要形成α型Sb2O3。上述结果证实,高浓度条件下,Sb(Ⅲ)可能在矿物材料发生沉积现象,生成α型Sb2O3,与化学吸附态Sb(Ⅲ)相比,这类Sb可能具有更高的环境迁移性,因此具有更高的环境风险,值得关注。
表 3 Sb(Ⅲ)或Sb(Ⅴ)氧化物和相关矿物的拉曼光谱特征峰位及归属Table 3. The characteristic Raman peaks of Sb(Ⅲ) or Sb(Ⅴ) oxides and the minerals and their assignment材料 特征峰
(cm−1)归属 材料 特征峰
(cm−1)归属 Sb2O3[38-39] 190 F2g振动 针铁矿[40-41] 224 Fe—O拉伸振动 374 F2g振动 405 Fe—OH 拉伸振动 452 Ag振动 666 Fe—O拉伸振动 Sb2O5[42-43] 495 Sb-O伸缩振动 斜方锰矿[44-45] 575 Mn—O拉伸振动 635 Sb-O伸缩振动 645 Mn—O对称伸缩振动 赤铁矿[46-47] 227 A1g振动 高岭石[48-49] 189 A1g(ν1)AlO6振动 293 Eg振动 409 ν2(e)SiO4振动 413 Eg振动 460 ν2(e)SiO4振动 499 Eg振动 640 Si-O-Al伸缩振动 614 Eg振动 717 Si-O-Al伸缩振动 氧化铝[50-51] 378 Eg振动 787 OH伸缩振动 417 A1g振动 从上述结果可见,拉曼光谱可以较为简便地对Sb(Ⅲ)的沉积行为进行原位表征。但拉曼光谱的检测灵敏度较低,因此对于浓度较低的吸附态的Sb(Ⅴ)和Sb(Ⅲ),难以直接检测,结合表面增强拉曼光谱等技术,有望提高检测的灵敏度。
3. 结论
选取6种土壤中典型矿物(赤铁矿、针铁矿、水铁矿、氧化铝、斜方锰矿和高岭石),研究了Sb(Ⅲ)和Sb(Ⅴ)在上述矿物表面的吸附热、动力学行为,并采用拉曼光谱对吸附界面的锑进行了原位表征。研究结果表明,选取的矿物对锑的吸附量有以下顺序:水铁矿>斜方锰矿>针铁矿>赤铁矿>氧化铝>高岭石;铁氧化物对锑有较强的吸附性,其中水铁矿由于其较大的比表面积,吸附贡献较大;斜方锰矿由于具有较强的氧化能力,可通过氧化作用氧化Sb(Ⅲ),该过程中矿物结构可能发生改变,从而进一步增强对锑的吸附能力;氧化铝和高岭石由于与锑的亲和力较弱,对锑的吸附贡献较小。pH影响实验证实,静电吸附作用对Sb(Ⅴ)的吸附有一定的贡献,但整体而言Sb(Ⅴ)和Sb(Ⅲ)主要依靠化学吸附在矿物表面进行吸附。高浓度吸附等温线实验和拉曼光谱表征结果证实,在较高平衡浓度下,Sb(Ⅴ)主要发生化学吸附,而Sb(Ⅲ)可能在矿物表面发生沉积,生成α型Sb2O3,从而产生与化学吸附态Sb(Ⅲ)不同的环境迁移行为。
拉曼光谱可方便地用于矿物表面吸附态和沉积态锑的原位光谱表征。但实际土壤中各矿物组分的含量可能有显著差异,要准确评价锑在实际土壤中的吸附、迁移行为,还需要系统地表征各组分的含量、粒度信息,同时结合实际土壤的理化条件(如pH、离子强度、水分和有机质等),综合分析锑的环境行为。
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图 1 沉积物还原性无机硫连续提取装置
实验装置部件包含:1—氮气瓶;2—减压阀;3—第一气体流量计;4—第二气体流量计;5—层析柱玻璃弯头;6—层析柱;7—层析柱阀门;8—分液漏斗玻璃弯头;9—分液漏斗;10—分液漏斗阀门;11—冷凝管玻璃弯头;12—冷凝管;13—蠕动泵;14—烧杯;15—烧瓶玻璃弯头;16—四口烧瓶(反应器);17—加热装置;18—试管玻璃弯头;19—玻璃试管。
Figure 1. The device for continuous extracting the reduced inorganic sulfur from sediments
including: 1—nitrogen cylinder, 2—pressure reducing valve, 3—the first gas flowmeter, 4—the second gas flowmeter, 5—glass elbow, 6—chromatography column, 7—valve of chromatography column, 8—glass elbow of dispenser funnel, 9—dispenser funnel, 10—valve of dispenser funnel, 11—glass elbow of condenser tube, 12—condenser tube, 13—peristaltic pump, 14—beaker, 15—glass elbow of flask, 16—four-mouth flask (reactor), 17—heating mantle, 18—glass elbow of tube, 19—glass tube.
表 1 重复实验与加标实验结果
Table 1 Results of repeated experiment and spike recovery in AVS, CRS, and ES procedures.
硫形态 重复实验 加标实验(回收率) 第一次实验(μmol/g) 第二次实验(μmol/g) 第三次实验(μmol/g) 平均值(μmol/g) RSD(%) 第一次实验(%) 第二次实验(%) 第三次实验(%) 平均值(%) RSD(%) 酸挥发性硫(AVS) 0.20 0.19 0.18 0.19 5.26 91.6 93.2 93.6 92.8 1.14 黄铁矿硫(CRS) 3.13 3.06 3.12 3.10 1.22 93.4 95.7 91.7 93.6 2.14 元素硫(ES) 0.38 0.38 0.36 0.37 3.09 94.6 93.8 93.9 94.1 0.46 -
[1] Wang J, Chen J, Guo J, et al. Speciation and transfor-mation of sulfur in freshwater sediments: A case study in southwest China[J]. Water Air Soil Pollut, 2017, 228(10): 392. doi: 10.1007/s11270-017-3580-5
[2] 毛立, 孙志高, 陈冰冰, 等. 闽江河口互花米草入侵湿地土壤无机硫赋存形态及其影响因素[J]. 生态学报, 2021, 41(12): 4840-4852. https://www.cnki.com.cn/Article/CJFDTOTAL-STXB202112018.htm Mao L, Sun Z G, Chen B B, et al. Variations of inorganic sulfur fractions and main influencing factors in marsh soils with different years of spartina alterniflora invasion in the Min River Estuary[J]. Acta Ecologica Sinica, 2021, 41(12): 4840-4852. https://www.cnki.com.cn/Article/CJFDTOTAL-STXB202112018.htm
[3] Lu Q Q, Bai J H, Yan D H, et al. Sulfur forms in wetland soils with different flooding periods before and after flow-sediment regulation in the Yellow River Delta, China[J]. Journal of Cleaner Production, 2020, 276(8): 122969.
[4] 陈伟锐. 高频红外碳硫仪测定土壤和水系沉积物中的硫实验条件改进[J]. 岩矿测试, 2019, 38(1): 123-128. doi: 10.15898/j.cnki.11-2131/td.201804160045 Chen W R. Improvement of experimental conditions for the determination of sulfur in soil and stream sediments by high frequency infrared carbon and sulfur analyzer[J]. Rock and Mineral Analysis, 2019, 38(1): 123-128. doi: 10.15898/j.cnki.11-2131/td.201804160045
[5] Jiang M, Sheng Y Q, Liu Q Q, et al. Conversion mecha-nisms between organic sulfur and inorganic sulfur in surface sediments in coastal rivers[J]. Science of the Total Environment, 2021, 752: 141829. doi: 10.1016/j.scitotenv.2020.141829
[6] 陈冰冰, 孙志高, 孙文广, 等. 外源氮输入对生长季黄河口碱蓬湿地土壤无机硫形态变化特征的影响[J]. 水土保持学报, 2018, 32(5): 277-286. doi: 10.13870/j.cnki.stbcxb.2018.05.044 Chen B B, Sun Z G, Sun W G, et al. Effects of exogenous nitrogen enrichment on variations of inorganic sulfur fractions in soils of suaeda salsa marsh in the Yellow River Estuary during the growing season[J]. Journal of Soil and Water Conservation, 2018, 32(5): 277-286. doi: 10.13870/j.cnki.stbcxb.2018.05.044
[7] Huerta-Diaz M A, Tessier A, Carignan R. Geochemistry of trace metals associated with reduced sulfur in freshwater sediments[J]. Applied Geochemistry, 1998, 13(2): 213-233. doi: 10.1016/S0883-2927(97)00060-7
[8] 刘崴, 胡俊栋, 杨红霞, 等. 电感耦合等离子体质谱联用技术在元素形态分析中的应用进展[J]. 岩矿测试, 2021, 40(3): 327-339. doi: 10.15898/j.cnki.11-2131/td.202006110089 Liu W, Hu J D, Yang H X, et al. Research progress on elemental speciation analysis by inductively coupled plasma-mass spectrometry hyphenated techniques[J]. Rock and Mineral Analysis, 2021, 40(3): 327-339. doi: 10.15898/j.cnki.11-2131/td.202006110089
[9] 李力, 王小静, 刘季花. 沉积物中酸可挥发性硫化物的分析方法研究[J]. 海洋与湖沼, 2015, 46(1): 96-101. https://www.cnki.com.cn/Article/CJFDTOTAL-HYFZ201501012.htm Li L, Wang X J, Liu J H. Analytical method of acid volatile sulfide in sediment[J]. Oceanologia et Limnologia Sinica, 2015, 46(1): 96-101. https://www.cnki.com.cn/Article/CJFDTOTAL-HYFZ201501012.htm
[10] 徐程, 杨斌, 朱雪菁, 等. 大风江口海域沉积物酸可挥发性硫化物、重金属分布及风险评价[J]. 环境科学研究, 2020, 33(6): 1530-1538. https://www.cnki.com.cn/Article/CJFDTOTAL-HJKX202006026.htm Xu C, Yang B, Zhu X Q, et al. Distribution and risk assessment of acid volatile sulfide and heavy metals in sediments of Dafengjiang River Estuary[J]. Research of Environmental Sciences, 2020, 33(6): 1530-1538. https://www.cnki.com.cn/Article/CJFDTOTAL-HJKX202006026.htm
[11] Souza L R, Knöller K, Ladeira A C Q. Sulfur isotope fractionation and sequential extraction to assess metal contamination on lake and river sediments[J]. Journal of Soils and Sediments, 2016, 16: 1986-1994. doi: 10.1007/s11368-016-1410-9
[12] Nriagu J O, Soon Y K. Distribution and isotopic com-position of sulfur in lake sediments of northern Ontario[J]. Geochimica et Cosmochimica Acta, 1985, 49(3): 823-834. doi: 10.1016/0016-7037(85)90175-9
[13] Duan W, Coleman M L, Pye K. Determination of reduced sulphur species in sediments—An evaluation and modified technique[J]. Chemical Geology, 1997, 141(3): 185-194.
[14] 曹爱丽, 周桂平, 胡姝, 等. 崇明东滩湿地沉积物中还原无机硫的形态特征[J]. 复旦学报(自然科学版), 2010, 49(5): 612-617. https://www.cnki.com.cn/Article/CJFDTOTAL-FDXB201005013.htm Cao A L, Zhou G P, Hu S, et al. Morphological characteristics of reduced inorganic sulfur in sediments of Dongtan Wetland in Chongming[J]. Journal of Fudan University (Natural Science), 2010, 49(5): 612-617. https://www.cnki.com.cn/Article/CJFDTOTAL-FDXB201005013.htm
[15] Hsieh Y P, Yang C H. Diffusion methods for the deter-mination of reduced inorganic sulfur species in sediments[J]. Limnology & Oceanography, 1989, 34(6): 1126-1130.
[16] Neretin L N, Böttcher M E, Jørgensen B B, et al. Pyriti-zation processes and greigite formation in the advancing sulfidization front in the upper Pleistocene sediments of the Black Sea[J]. Geochimica et Cosmochimica Acta, 2004, 68(9): 2081-2093.
[17] Burton E D, Sullivan L A, Bush R T, et al. A simple and inexpensive chromium-reducible sulfur method for acid-sulfate soils[J]. Applied Geochemistry, 2008, 23(9): 2759-2766.
[18] 黄志丁, 王军, 逯海, 等. 电感耦合等离子体质谱法测定硫时不同形态硫的影响[J]. 岩矿测试, 2012, 31(1): 77-82. http://www.ykcs.ac.cn/cn/article/id/ykcs_20120110 Huang Z D, Wang J, Lu H, et al. The effect on sulfur species during determination of sulfur by inductively coupled plasma-mass spectrometry[J]. Rock and Mineral Analysis, 2012, 31(1): 77-82. http://www.ykcs.ac.cn/cn/article/id/ykcs_20120110
[19] 张媛媛, 林学辉, 贺行良, 等. 离子色谱法同时测定海洋沉积物中氯和硫[J]. 分析科学学报, 2015, 31(2): 249-252. https://www.cnki.com.cn/Article/CJFDTOTAL-FXKX201502021.htm Zhang Y Y, Lin X H, He X L, et al. Determination of chlorine and sulfur in marine sediment by ion chromatography[J]. Journal of Analytical Science, 2015, 31(2): 249-252. https://www.cnki.com.cn/Article/CJFDTOTAL-FXKX201502021.htm
[20] Chen Y Q, Ge J W, Huang T, et al. Restriction of sulfate reduction on the bioavailability and toxicity of trace metals in Antarctic lake sediments[J]. Marine Pollution Bulletin, 2020, 151: 110807.
[21] 石友昌, 陈贵仁, 赵萌生, 等. 酸溶-电感耦合等离子体发射光谱法和燃烧-红外吸收法测定不同类型地球化学样品中的硫[J]. 岩矿测试, 2022, 41(4): 663-672. doi: 10.15898/j.cnki.11-2131/td.202108200104 Shi Y C, Chen G R, Zhao M S, et al. Determination of sulfur in different types of geochemical samples by ICP-OES with acid dissolution and combustion-infrared absorption spectrometry[J]. Rock and Mineral Analysis, 2022, 41(4): 663-672. doi: 10.15898/j.cnki.11-2131/td.202108200104
[22] 姜云军, 李星, 姜海伦, 等. 四酸敞口溶解-电感耦合等离子体发射光谱法测定土壤中的硫[J]. 岩矿测试, 2018, 37(2): 152-158. doi: 10.15898/j.cnki.11-2131/td.201704010048 Jiang Y J, Li X, Jiang H L, et al. Determination of sulfurin soil by inductively coupled plasma-optical emission spectrometry with four acids open dissolution[J]. Rock and Mineral Analysis, 2018, 37(2): 152-158. doi: 10.15898/j.cnki.11-2131/td.201704010048
[23] Hsieh Y P, Shieh Y N. Analysis of reduced inorganic sulfur by diffusion methods: Improved apparatus and evaluation for sulfur isotopic studies[J]. Chemical Geology, 1997, 137(3): 255-261.
[24] 李肖, 赵新如, 周芬琦, 等. 安徽庐江钟山尾矿区河流水体硫形态及硫同位素分布特征[J]. 环境化学, 2021, 40(6): 1787-1794. https://www.cnki.com.cn/Article/CJFDTOTAL-HJHX202106016.htm Li X, Zhao X R, Zhou F Q, et al. Distribution characteristics of sulfur species and isotopes in sediments of rivers around Zhongshan tailing at Lujiang County, Anhui Province[J]. Environmental Chemistry, 2021, 40(6): 1787-1794. https://www.cnki.com.cn/Article/CJFDTOTAL-HJHX202106016.htm
[25] 王小芳, 李方晓, 黄涛, 等. 安徽铜陵铜尾矿硫形态及硫同位素分布特征[J]. 中国环境科学, 2019, 39(4): 1664-1671. https://www.cnki.com.cn/Article/CJFDTOTAL-ZGHJ201904045.htm Wang X F, Li F X, Huang T, et al. Distribution characteristics of sulfur species and isotopes in a copper tailing at Tongling, Anhui Province[J]. China Environ-mental Science, 2019, 39(4): 1664-1671. https://www.cnki.com.cn/Article/CJFDTOTAL-ZGHJ201904045.htm
[26] 程思海, 陈道华, 雷知生. 使用元素分析仪测定海洋沉积物中的硫化物[J]. 岩矿测试, 2011, 30(1): 63-66. http://www.ykcs.ac.cn/cn/article/id/ykcs_20110113 Cheng S H, Chen D H, Lei Z S. Determination of sulfide in marine sediments by elemental analyzer[J]. Rock and Mineral Analysis, 2011, 30(1): 63-66. http://www.ykcs.ac.cn/cn/article/id/ykcs_20110113
[27] Sheng Y Q, Sun Q Y, Shi W J, et al. Geochemistry of reduced inorganic sulfur, reactive iron, and organic carbon in fluvial and marine surface sediment in the Laizhou Bay region, China[J]. Environmental Earth Sciences, 2015, 74(2): 1151-1160.
[28] 吴松峻, 汪旋, 季秋忆, 等. 太湖西岸典型区域沉积物的硫铁分布特征及环境意义[J]. 湖泊科学, 2019, 31(4): 950-960. https://www.cnki.com.cn/Article/CJFDTOTAL-FLKX201904006.htm Luo S J, Wang X, Ji Q Y, et al. Iron-sulfur distribution and its environmental significance in three typical areas of western Lake Taihu[J]. Journal of Lake Sciences, 2019, 31(4): 950-960. https://www.cnki.com.cn/Article/CJFDTOTAL-FLKX201904006.htm
[29] Chen Y Q, Shen L L, Huang T, et al. Transformation of sulfur species in lake sediments at Ardley Island and Fildes Peninsula, King George Island, Antarctic Peninsula[J]. Science of tThe Total Environment, 2020, 703: 135591.
[30] 尹洪斌, 范成新, 丁士明, 等. 太湖沉积物中无机硫的化学特性[J]. 中国环境科学, 2008, 28(2): 183-187. https://www.cnki.com.cn/Article/CJFDTOTAL-ZGHJ200802019.htm Yin H B, Fan C X, Ding S M, et al. The chemical characteristics of inorganic sulfur in Taihu Lake sediments[J]. China Environmental Science, 2008, 28(2): 183-187. https://www.cnki.com.cn/Article/CJFDTOTAL-ZGHJ200802019.htm
[31] Leonard E N, Mattson V R, Benoit D A, et al. Seasonal variation of acid volatile sulfide concentration in sediment cores from three northeastern Minnesota Lakes[J]. Hydrobiologia, 1993, 271(2): 87-95.
[32] 朱瑾灿, 吴雨琛, 尹洪斌. 太湖蓝藻聚集区沉积物硫形态的时空变异特征[J]. 中国环境科学, 2017, 37(12): 4690-4700. https://www.cnki.com.cn/Article/CJFDTOTAL-ZGHJ201712040.htm Zhu J C, Wu Y C, Yin H B. Spatial and temporal variation of sulfur speciation in sediments from cyanobacteria accumulation in Taihu Lake, China[J]. China Environmental Science, 2017, 37(12): 4690-4700. https://www.cnki.com.cn/Article/CJFDTOTAL-ZGHJ201712040.htm
[33] Howard D E, Evans R D. Acid-volatile sulfide (AVS) in a seasonally anoxic mesotrophic lake: Seasonal and spatial changes in sediment AVS[J]. Environmental Toxicology and Chemistry: An International Journal, 1993, 12(6): 1051-1057.
[34] Oehm N J, Luben T J, Ostrofsky M L. Spatial distribution of acid-volatile sulfur in the sediments of Canadohta Lake, PA[J]. Hydrobiologia, 1997, 345(1): 79-85.
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