Fine quantitative characterization of high-H2S gas reservoirs under the influence of liquid sulfur deposition and adsorption

In order to clarify the influence of liquid sulfur deposition and adsorption to high-H2S gas reservoirs,three types of natural cores with typical carbonate pore structures were selected for high-temperature and high-pressure core displacement experiments.Fine quantitative characterization of the cores in three steady states(original,after sulfur injection,and after gas flooding)was carried out using the nuclear magnetic resonance(NMR)transverse relaxation time spectrum and imaging,X-ray computer tomography(CT)of full-diameter cores,basic physical property testing,and field emission scanning electron microscopy imaging.The loss of pore volume caused by sulfur deposition and adsorption mainly comes from the medium and large pores with sizes bigger than 1000μm.Liquid sulfur has a stronger adsorption and deposition ability in smaller pore spaces,and causes greater damage to reservoirs with poor original pore structures.The pore structure of the three types of carbonate reservoirs shows multiple fractal characteristics.The worse the pore structure,the greater the change of internal pore distribution caused by liquid sulfur deposition and adsorption,and the stronger the heterogeneity.Liquid sulfur deposition and adsorption change the pore size distribution,pore connectivity,and heterogeneity of the rock,which further changes the physical properties of the reservoir.After sulfur injection and gas flooding,the permeability of TypeⅠreservoirs with good physical properties decreased by 16%,and that of TypesⅡandⅢreservoirs with poor physical properties decreased by 90%or more,suggesting an extremely high damage.This indicates that the worse the initial physical properties,the greater the damage of liquid sulfur deposition and adsorption.Liquid sulfur is adsorbed and deposited in different types of pore space in the forms of flocculence,cobweb,or retinitis,causing different changes in the pore structure and physical property of the reservoir.

Study of the reaction mechanism for preparing powdered activated coke with SO_(2)adsorption capability via one-step rapid activation method under flue gas atmosphere

In this study,the impact of different reaction times on the preparation of powdered activated carbon(PAC)using a one-step rapid activation method under flue gas atmosphere is investigated,and the underlying reaction mechanism is summarized.Results indicate that the reaction process of this method can be divided into three stages:stage I is the rapid release of volatiles and the rapid consumption of O_(2),primarily occurring within a reaction time range of 0-0.5 s;stage II is mainly the continuous release and diffusion of volatiles,which is the carbonization and activation coupling reaction stage,and the carbonization process is the main in this stage.This stage mainly occurs at the reaction time range of 0.5 -2.0 s when SL-coal is used as material,and that is 0.5-3.0 s when JJ-coal is used as material;stage III is mainly the activation stage,during which activated components diffuse to both the surface and interior of particles.This stage mainly involves the reaction stage of CO_(2)and H2O(g)activation,and it mainly occurs at the reaction time range of 2.0-4.0 s when SL-coal is used as material,and that is 3.0-4.0 s when JJ-coal is used as material.Besides,the main function of the first two stages is to provide more diffusion channels and contact surfaces/activation sites for the diffusion and activation of the activated components in the third stage.Mastering the reaction mechanism would serve as a crucial reference and foundation for designing the structure,size of the reactor,and optimal positioning of the activator nozzle in PAC preparation.

A functionalized activated carbon adsorbent prepared from waste amidoxime resin by modifying with H_(3)PO_(4) and ZnCl_(2) and its excellent Cr(Ⅵ)adsorption

With the application of resins in various fields, numerous waste resins that are difficult to treat have been produced. The industrial wastewater containing Cr(Ⅵ) has severely polluted soil and groundwater environments, thereby endangering human health. Therefore, in this paper, a novel functionalized mesoporous adsorbent PPR-Z was synthesized from waste amidoxime resin for adsorbing Cr(Ⅵ). The waste amidoxime resin was first modified with H3PO4 and ZnCl_(2), and subsequently, it was carbonized through slow thermal decomposition. The static adsorption of PPR-Z conforms to the pseudo-second-order kinetic model and Langmuir isotherm, indicating that the Cr(Ⅵ) adsorption by PPR-Z is mostly chemical adsorption and exhibits single-layer adsorption. The saturated adsorption capacity of the adsorbent for Cr(Ⅵ) could reach 255.86 mg/g. The adsorbent could effectively reduce Cr(Ⅵ) to Cr(Ⅲ) and decrease the toxicity of Cr(Ⅵ) during adsorption. PPR-Z exhibited Cr(Ⅵ) selectivity in electroplating wastewater. The main mechanisms involved in the Cr(Ⅵ) adsorption are the chemical reduction of Cr(Ⅵ) into Cr(Ⅲ) and electrostatic and coordination interactions. Preparation of PPR-Z not only solves the problem of waste resin treatment but also effectively controls Cr(Ⅵ) pollution and realizes the concept of “treating waste with waste”.

电厂粉煤灰、炉渣和污泥复合陶粒对低浓度Pb^(2+)的吸附特性

针对重金属污染具有来源广、危害大等特点,通过以电厂废物(粉煤灰、炉渣)和脱水污泥为原料制备一种高效且价廉的陶粒吸附剂,采用吸附影响因素实验、解吸再生实验、吸附动力学模型和等温吸附模型的拟合以及陶粒表征分析,探究陶粒对Pb^(2+)的吸附特性,同时为实现废物资源化利用提供新思路.结果表明:陶粒去除Pb^(2+)的较佳吸附条件为粒径4 mm、pH 4.5~5.0、吸附时间360 min、吸附温度25℃.陶粒再生所用较佳解吸剂为0.5 mol/L的HCl溶液,较佳解吸时间和次数分别为120 min和5次,解吸5次后陶粒对Pb^(2+)的去除率为92.67%.此吸附过程更好地遵循了准二级动力学模型和Freundlich等温吸附模型.陶粒上的O-H、Si-O和金属氧化键在吸附Pb^(2+)的过程中起主要作用.陶粒吸附Pb^(2+)后,出现了新的物相Pb_(2)Cl_(3)OH和PbO,陶粒与Pb^(2+)之间发生化学吸附,为自发进行的放热反应.陶粒处理实际废水中Pb^(2+)的去除率可达93.70%,Pb^(2+)浓度由3.74 mg/L降至0.24 mg/L.研究显示,电厂粉煤灰、炉渣和污泥复合陶粒对Pb^(2+)具有一定的去除效果,可为以固体废物为原料制备的吸附剂在重金属废水处理应用中提供数据支撑.

磁性三乙烯四胺/单宁树脂对Cu^(2+)、Pb^(2+)的吸附性能研究

利用曼尼希反应将三乙烯四胺(TETA)固化到单宁(TA)基体表面,热溶剂法制得磁性单宁基树脂(MTETA-TA)。通过红外光谱、扫描电镜、比表面积及孔隙度分析仪、振动样品磁强计对M-TETA-TA进行表征,表明M-TETA-TA具有疏水性强、比表面积大的优势,Fe_(3)O_(4)的成功引入有效解决吸附剂回收难的问题。对含Cu^(^(2+))、Pb^(2+)废水溶液进行了静态吸附实验,探讨了其对金属的吸附性能。在pH为5的酸性条件下,吸附效果较好;Cu^(^(2+))和Pb^(2+)吸附动力学均符合准二级反应动力学模型,主要为化学吸附;Cu^(^(2+))的吸附等温线符合Langmuir模型,属单层吸附,理论吸附最大值为173.33 mg·g^(-1);Pb^(2+)的吸附等温线符合Sips模型,属多层吸附,理论吸附最大值为217.14 mg·g^(-1)。推测M-TETA-TA对Pb^(2+)的吸附除了螯合、氧化还原等化学反应,还存在静电和离子交换作用,氨基和酚羟基为主要参与官能团。循环再生5次后,仍有较高的吸附性能和磁性强度。

玉米秸秆复合高吸水树脂的制备及对Pb^(2+)的吸附研究

以来源丰富的玉米秸秆、高岭土为原料,以丙烯酸、丙烯酰胺为聚合单体,通过水溶液聚合法制备了复合高吸水树脂,并用红外光谱(FT-IR)和扫描电镜(SEM)对其结构进行了表征分析。利用合成的复合高吸水树脂对含Pb^(2+)模拟废水进行了吸附研究,考察了复合高吸水树脂用量、Pb^(2+)初始浓度、吸附时间和溶液pH及对Pb^(2+)去除率的影响,最优条件下复合高吸水树脂对Pb^(2+)的去除率达88.57%,吸附Pb^(2+)后的复合高吸水树脂经处理后可循环使用。

碳化处理对再生微粉吸附Pb^(2+)行为与机理的影响

随着工业的发展,大量含铅废弃物被排放到环境中,给水体带来了严重的污染。本研究采用经碳化处理的再生混凝土微粉(CRCF)作为吸附剂,针对硝酸铅配制的铅污染溶液开展吸附试验,并测试分析了吸附剂的物相、微观结构和稳定性。研究表明,CRCF对Pb^(2+)具有良好的吸附效果,24 h后可达到93.1%(质量分数,下同)的去除率;CRCF对Pb^(2+)的吸附稳定性较高,吸附后仅有极少量的Pb^(2+)浸出;吸附反应中,Pb^(2+)静电吸附在CRCF表面,与CRCF发生离子交换并在表面形成碳酸盐沉淀,最终主要以碳酸盐的形式固定在CRCF中;CRCF可作为一种低成本的Pb^(2+)高效吸附剂,可有效应用于含铅废水的治理,实现废物资源化再利用。

Pb^(2+)对掺杂硼硅酸盐玻璃中CsPbBr_(3)钙钛矿量子点发光性能的影响

硼硅酸盐玻璃包覆钙钛矿CsPbBr_(3)量子点(PQDs@glass)能够大幅提高PQDs的稳定性,使其在LED照明和显示技术中拥有广泛的应用空间。然而,玻璃包覆的同时也导致了PQDs发光强度与量子产率降低。本工作为提高其发光强度探讨了热诱导温度及Pb^(2+)的含量对PQDs@glass结构的影响,当热诱导温度为460℃,Pb^(2+)浓度为6 mol时,其发光强度最高。研究发现,Pb^(2+)浓度的增加会导致玻璃网状结构的致密化,改变玻璃组分的扩散行为,影响PQDs的析晶过程,导致PQDs@glass发光强度的变化。本工作得到量子产率高达95.6%的PQDs@glass,并实现了硼硅酸盐玻璃基质内PQDs的尺寸可控制备。结果表明,PQDs尺寸分布在10 nm左右,超过86%的颗粒尺寸在6~14 nm内,且具有优越的稳定性,经历10次室温至200℃热循环后,发光强度仍能保持初始强度的98.9%。最后,为了验证其在LED照明及显示领域的应用,将制备的量子点微晶玻璃粉料与二甲基硅氧烷(PDMS)混合,得到的LED器件性能优异,色域范围覆盖110%sRGB。本研究为PQDs@glass的大规模制备及其在LED器件领域的应用奠定了基础。

酸改性污泥基复合陶粒对Pb^(2+)的吸附性能研究

以污泥、磷尾矿和赤泥为原料制备陶粒,用盐酸、硝酸和柠檬酸进行改性,研究陶粒对水中Pb^(2+)的吸附效果,并通过扫描电镜(SEM)、表面基团、零电荷点(pHPZC)和傅里叶红外光谱(FTIR)分析陶粒对Pb^(2+)的吸附机理。结果表明,低浓度盐酸或硝酸改性陶粒对Pb^(2+)的去除率更好,柠檬酸改性陶粒对Pb^(2+)的去除率低于未改性陶粒。酸改性陶粒具有比表面积大、孔隙结构发达、酸性基团含量多、等电点低等特点,对Pb^(2+)的吸附同时存在物理吸附和化学吸附过程,可用作含Pb^(2+)废水的处理材料。

NaOH提取香蕉皮纤维对水中Pb^(2+)的吸附特性及机理研究

为探讨生物质纤维吸附材料对水中Pb^(2+)的吸附特性,以香蕉皮为原料,采用NaOH提取纤维吸附水中的Pb^(2+)。研究结果表明,在实验条件范围内,香蕉皮纤维对Pb^(2+)的理论饱和吸附量可达130.74 mg·g^(-1),远强于香蕉皮(57.44 mg·g^(-1)),其吸附平衡时间为90 min,低于香蕉皮粉末(120 min)。香蕉皮纤维对水中Pb^(2+)的吸附过程符合Langmuir等温模型和准二级动力学模型,拟合结果显示,香蕉皮粉末对Pb^(2+)的吸附亲和力较强。BET比表面积、扫描电镜、EDS能谱、傅里叶变换红外光谱表征结果表明,香蕉皮纤维较香蕉皮,其主要官能团结构未发生明显变化,但其表面形态和元素构成均发生了有利于Pb^(2+)吸附的变化。

Pb^(2+)的检测及去除方法研究进展

近年来铅污染问题日益加重,需要高效、准确、快速的Pb^(2+)检测方法。总结了Pb^(2+)的危害及原子吸收光谱法、高分辨率连续源石墨炉原子吸收光谱法、紫外可见分光光谱法、电化学分析法等检测技术,并对其优缺点进行了简要说明。同时介绍了Pb^(2+)的去除方法及其实际应用,最后对该领域的发展前景进行了展望。

铁改性生物炭对黄绵土Pb^(2+)运移过程影响及模型分析

[目的]明确不同铁改性生物炭施加量下土壤重金属的运移过程,以期为黄土区土壤重金属污染防治提供理论依据。[方法]以铁改性生物炭与黄绵土质量比分别为0%(CK),1%(A_(1)),2%(A_(2)),3%(A_(3)),4%(A_(4))和5%(A_(5))6组处理为研究对象,以Pb^(2+)为示踪离子,利用室内土柱进行溶质运移模拟试验,研究了不同铁改性生物炭施加量对黄绵土中Pb^(2+)运移过程的影响并进行模型模拟。[结果](1)A_(1),A_(2),A_(3),A_(4)和A_(5)处理的饱和导水率(K_(s))比CK分别减少了6.90%,20.70%,27.60%,31.03%和37.93%,即K s随铁改性生物炭施加量增大而逐渐减小。(2)不同处理的Pb^(2+)浓度达到平衡时的总历时比CK分别延长了1.79,13.00,34.98,35.34,40.81 h,随铁改性生物炭施加量增加,重金属初始和完全穿透时间明显推迟。(3)两区模型(TRM)和对流-弥散方程(CDE)的拟合曲线均能与实测曲线较好吻合,但TRM的决定系数(R^(2))大于CDE,均方根误差(RMSE)小于CDE,因此TRM的模拟精度更高。[结论]土壤中施加铁改性生物炭能较好地减缓重金属的运移过程,对调控土壤中重金属运移及防止地下水污染具有重要作用。

Fe_(3)O_(4)掺杂改性电极电化学去除Pb^(2+)的效能研究

为了实现水体中Pb^(2+)的高效电化学去除,采用涂覆法将Fe_(3)O_(4)、粉末活性炭、乙炔黑和聚乙烯醇混合后负载于石墨纸上,制备得到了Fe_(3)O_(4)掺杂改性电极。采用差分柱批式反应器模式进行电化学去除Pb^(2+)实验,考察了电压、温度、运行时间、Pb^(2+)质量浓度对去除Pb^(2+)的影响并评估了电极的重复利用性和稳定性。结果表明,所制备的电极表面孔隙丰富,孔径均匀。电压为1.4 V时,运行150 min后电化学体系对Pb^(2+)的去除率达到了98.73%,延长运行时间可以显著强化Pb^(2+)的去除率。在10~35℃的温度范围内,温度升高有利于Pb^(2+)的电化学去除,电化学体系在不同的Pb^(2+)浓度下均有较好的适用性和适应性,随着Pb^(2+)初始浓度的升高,处理单位体积含Pb^(2+)废水的能耗逐渐增加,但去除单位质量Pb^(2+)的能耗反而降低,拟合结果表明Pb^(2+)的去除过程符合准一级动力学。经过8次循环后,电化学体系仍保持原有的Pb^(2+)去除效果。

基于发夹DNA动态自组装树枝状聚合物放大策略的荧光传感体系测定水中Pb^(2+)的含量

基于GR-5脱氧核酶(GR-5 DNAzyme)对Pb^(2+)的特异性识别和发夹DNA动态自组装树枝状聚合物信号放大策略,构建了一种新型无酶、高灵敏检测Pb^(2+)的荧光传感体系。分别于95℃恒温孵育合成序列扩展GR-5 DNAzyme复合物(GR-5E-S,由GR-5 DNAzyme酶链GR-5E和底物链GR-5S合成)以及Y型骨架(由骨架链Y1、Y2、Y3合成),于25℃恒温孵育合成发夹三聚体(由Y型骨架和发夹链H1、H2、H3合成,其中发夹链H1上修饰有荧光团和猝灭团)。将水样4μL添加到96μL含400 nmol·L^(-1)GR-5E-S,400 nmol·L^(-1)发夹三聚体的反应溶液中,于25℃孵育40 min。当水样中存在Pb^(2+)时,GR-5E-S识别Pb^(2+),底物链被切割,酶链和底物链分开并释放出目标链T,目标链T与发夹链H1杂交触发动态自组装过程,生成树枝状聚合物,于520 nm处测量荧光强度。结果显示:建立的荧光传感体系可在40 min内完成检测;Pb^(2+)的浓度在0.1~10.0 nmol·L^(-1)内与对应的传感体系的荧光强度呈线性关系,检出限(3s/k)为19 pmol·L^(-1);按照标准加入法进行回收试验,回收率为98.0%~108%,测定值的相对标准偏差(n=5)不大于15%。

香草醛取代的苝酰亚胺荧光探针的制备及对Pb^(2+)的识别

将苝酰亚胺衍生物作为荧光团,以苝四酸酐和香草醛为原料,设计并合成了一种高效、有特定反应性能的新型苝酰亚胺类Pb^(2+)荧光探针N,N-双香草醛基-1,6,7,12-四氯-3,4:9,10-苝二酰亚胺(PDI-VBD)。通过质谱、核磁等检测手段对探针分子PDI-VBD的结构进行表征,利用紫外-可见吸收光谱和荧光光谱法探究了探针PDI-VBD对Pb^(2+)的荧光识别性能。光谱分析研究结果显示,在NMP/H_(2)O溶液体系中,探针分子PDI-VBD对Pb^(2+)显示出较强的选择性识别能力和较高的灵敏度,即苝酰亚胺衍生物PDI-VBD自身的荧光较弱,但与Pb^(2+)结合之后,生成了具有较强荧光的配位化合物。金属离子共存实验证明此荧光探针对Pb^(2+)选择性高,且不受其他金属离子干扰。结果表明,香草醛取代的苝酰亚胺衍生物PDI-VBD是一种新型Pb^(2+)荧光探针,选择性好、灵敏度高,可用于实际水样、食品及环境中重金属Pb^(2+)的检测。

重金属Pb^(2+)对早熟禾种子萌发的影响

[目的]探究重金属铅对早熟禾种子萌发的影响。[方法]用不同浓度Pb^(2+)(20、40、60、80 mg/L)处理早熟禾种子,测定Pb2+对早熟禾种子萌发、叶绿素以及生根等指标的影响。[结果]随着Pb2+浓度的增加,草籽的萌发率、发芽指数降低,但降低趋势不明显。逐日萌发率在第3天出现高峰,早熟禾的根茎长度呈下降趋势。叶绿素a、叶绿素b含量降低明显,类胡萝卜素含量在Pb^(2+)浓度80 mg/L时增加。[结论]早熟禾种子的萌发率在Pb^(2+)浓度20~80 mg/L范围内受影响较小,而叶绿素含量、类胡萝卜素含量以及幼苗根茎的生长受到一定的抑制。

姜黄素修饰CNC传感器与水凝胶制备及其检测和去除Pb^(2+)的研究

本研究利用EDC/NHS耦合法将姜黄素(Cur)接枝于羧基化纤维素纳米晶体(CCNC),制备纳米纤维素接枝姜黄素(CCNC-Cur)传感器和CCNC-Cur复合海藻酸钠(CCNC-Cur-SA)水凝胶吸附剂,用于检测和去除Pb^(2+)。结果表明,CCNC-Cur传感器可特异性吸附Pb2+,利用Image J软件对传感器的颜色深度进行数字化处理后,得到Pb^(2+)的检出限为6.25 mg/L;在静态吸附实验的优化条件下(吸附时间105 min、pH值=5、吸附剂用量0.08 g),CCNC-Cur-SA水凝胶对Pb2+的吸附量达98.3 mg/g。

化学老化对Zn改性生物炭性质及吸附Pb^(2+)的影响

本文采用60及90℃非生物化学老化方法,对ZnSO_(4)浸渍改性生物炭(PRZn)进行了为期6个月的老化试验.通过元素分析仪,比表面积分析仪,X射线光电子能谱法和傅里叶红外光谱等手段明确老化后生物炭性质的变化特点,并利用等温吸附实验比较老化对Zn改性生物炭Pb^(2+)吸附性能的差异.结果表明,化学老化过程会生成活性自由基,显著增加生物炭表面含氧官能团的数量,导致500℃制备的PRZn老化后比表面积显著提高(从24.67m^(2)/g提升到85.51m^(2)/g),改性引入的Zn氧化物从晶型结构转化为有机结合态,因此,PRZn经60℃老化后,其对Pb^(2+)的吸附量从31.18mg/g提高至47.70mg/g.但经90℃老化后,700℃制备的PRZn吸附量变化不大,这主要是老化过程中产生的活性氧化物质在90℃下发生自猝灭过程,且700℃制备的PRZn碳结构相对稳定,导致老化后含氧官能团的量没有显著升高而比表面积下降.本研究结果将为改性后老化生物炭在铅污染土壤中的长期利用提供具体理论依据.

水相单层氨基改性二氧化硅的制备及Pb^(2+)吸附效果

采用硅烷偶联剂γ-氨丙基三乙氧硅烷(APTES)和(β-氨乙基)-γ-氨丙基三甲氧基硅烷(AEAPTMS),通过水相工艺分别制备出单层氨基改性二氧化硅(SiO_(2)-APTES和SiO_(2)-AEAPTMS,用作吸附剂),采用透射电子显微镜、红外光谱分析仪、热重-差热分析仪、元素分析仪等仪器对其进行了表征,考察了Pb^(2+)吸附效果的影响因素,确定了最佳吸附条件。结果表明:当偶联剂添加量(质量分数)小于15%时,可实现二氧化硅的单层氨基改性;在初始Pb^(2+)质量浓度为200 mg/L,pH值为6,吸附时间为60 min的优化条件下,SiO_(2)-APTES和SiO_(2)-AEAPTMS对Pb^(2+)的最大吸附量分别达到18.48,34.75 mg/g;吸附过程均符合拟二级动力学模型和Langmuir吸附模型,均为单分子层的化学吸附过程;吸附剂重复使用5次后,Pb^(2+)吸附量仍超过最大吸附量的90%,具有良好的循环使用性能。

Insights into carbon dioxide sequestration into coal seams through coupled gas flow-adsorption-deformation modelling

Injecting carbon dioxide(CO_(2))into coal seams may unlock substantial carbon sequestration potential.Since the coal acts like a carbon filter,it can preferentially absorb significant amounts of CO_(2).To explore this further,desorption of the adsorbed gas due to pressure drop is investigated in this paper,to achieve an improved understanding of the long-term fate of injected CO_(2) during post-injection period.This paper presents a dual porosity model coupling gas flow,adsorption and geomechanics for studying coupled processes and effectiveness of CO_(2) sequestration in coals.A new adsorption?desorption model derived based on thermodynamics is incorporated,particularly,the desorption hysteresis is considered.The reliability of the proposed adsorption-desorption isotherm is examined via validation tests.It is indicated that occurrence of desorption hysteresis is attributed to the adsorption-induced pore deformation.After injection ceases,the injected gas continues to propagate further from the injection well,while the pressure in the vicinity of the injection well experiences a significant drop.Although the adsorbed gas near the well also decreases,this decrease is less compared to that in pressure because of desorption hysteresis.The unceasing spread of CO_(2) and drops of pressure and adsorbed gas depend on the degree of desorption hysteresis and heterogeneity of coals,which should be considered when designing CO_(2) sequestration into coal seams.