钠基膨润土对重金属离子的吸附特征

探讨了在不同振荡时间、不同溶液重金属离子浓度、不同矿物颗粒细度和不同pH值条件下,钠基膨润土对Cu2+、Zn2+和Cd2+的吸附效果,讨论了钠基膨润土对重金属离子吸附的影响因素。结果表明:重金属离子在钠基膨润土表面的吸附是个迅速的过程,钠基膨润土对重金属的吸附在10 min内即可达最大值。钠基膨润土不同颗粒细度对重金属离子的去除率有所不同,但并非颗粒越细吸附量越大。就试验的3种重金属离子而言,钠基膨润土对其吸附效果均很好。较高的pH值有助于钠基膨润土对溶液中重金属离子的吸附,但考虑到实际操作的其它因素,不能把pH值调得过高。     

Adsorption of heavy metals by brewery biomass

In this work, biosorption of lead, copper and cadmium by waste brewery yeast has been studied. The adsorption capacity for lead, copper and cadmium on the biomass increased with the increasing temperature and the maximum uptakes were 0.465 mmolPb/g (96.4 mg/g), 0.769 mmolCu/g (48.9 mg/g) and 0.127 mmolCd/g (14.3 mg/g) at 308 K. The Langmuir isotherm, favorable type, and the pseudo second-order kinetic model represent our experimental data very well. The heat of biosorption was evaluated from the Langmuir isotherm equation, and the biosorption of lead, copper and cadmium was endothermic reaction.     

Characterization of mesoporous alumina prepared by surface alumination of SBA-15

Mesoporous aluminas of controlled pore sizes were synthesized by multiple grafting of Al isopropoxide in organic solvents on mesoporous silica SBA-15. These materials were characterized by N₂ physisorption, TEM, XRD, ²⁷Al NMR and their surface chemical properties were probed by DRIFT, cumene cracking and MoO₃ thermal spreading. The results show that the chemical nature of the Al-grafted materials varies continuously with the number of grafting from pure silica to pure alumina. Typically, after three graftings, this original method of synthesis allows one to prepare ordered mesoporous aluminas with specific surface areas above 300 m² g⁻¹ and a narrow pore size distribution centered on ca. 60 Å. In addition to the characterizations, different models were developed to understand the evolution of the specific surface area and to discard a possible pore blocking.     

表面活性剂对SBA-15分子筛吸附性能的影响

以聚醚P123为模板剂,正硅酸乙酯(TEOS)为硅源,在酸性条件下用微波辐射法制备SBA-15分子筛,研究了表面活性剂十二烷基苯磺酸钠和OP-10乳化剂的添加对分子筛的形貌和性质的影响.采用X-射线衍射仪(XRD)、傅里叶变换红外光谱仪(FT-IR)、扫描电镜(SEM)、Zeta电位分析仪对样品进行表征.研究了pH值、温度和初始浓度对三种分子筛样品吸附铜离子以及亚甲基蓝效果的影响.结果 表明,当Cu2初始浓度为5 mg/L,pH值为7～8,温度为25℃时,三种样品对Cu2的吸附率最大,均达到90％以上;亚甲基蓝溶液的初始浓度为20mg/L时,用OP-10制备的分子筛吸附率达到95％左右.SBA-15分子筛制备中添加少量的OP-10,使分子筛表面形成大量均匀分布的大孔结构,对水体中铜离子和亚甲基蓝表现出良好的吸附性能.     

浸渍法制备PW12／SBA-15催化合成柠檬酸三丁酯

以分子筛SBA-15为载体,采用浸渍法负载磷钨酸作催化剂,催化合成柠檬酸三丁酯.考察了醇酸比、反应温度、催化剂用量、反应时间等因素对酯化率的影响.实验表明,分子筛SBA-15负载磷钨酸作为柠檬酸合成催化剂,催化活性良好.适宜的反应条件:醇酸摩尔比为4:1,磷钨酸负载质量分数为27%,催化剂用量为反应物总质量的1.3%,反应时间为7 h,酯化率最高可达96%.     

Adsorption of heavy metals by pirymidine-derivated mesoporous hybrid material

This paper describes the synthesis of pyrimidine-derivated hybrid mesoporous material via chemical bonding. This has been done by modifying the silanol groups of the support with a synthesised pyrimidine propyl triethoxysilane. The hybrid material has been characterized by X-ray diffraction, nitrogen adsorption techniques, FT-IR, ²⁹Si and ¹³C MAS NMR. The potential of the material of removing heavy metal as copper, nickel and cobalt from water has been tested. Effects of pH, velocity of adsorption, selectivity, maximum adsorption capacity and preconcentration capacity have been determined.     

Adsorption equilibrium of heavy metals on natural zeolites

Prior to equilibrium experiments, a clinoptilolite-type Korean natural zeolite was pretreated with HCl, NaOH, and NaCl to improve the ion-exchange capacity for heavy metals. Singleand multi-species equilibrium data of heavy metals such as copper, cadmium, cesium, and lead on treated and untreated natural zeolites were measured experimentally. For single-species equilibrium data, one of the conventional adsorption isotherms, the Sips equation, was used to fit them and then multi-species equilibrium data were predicted by using the loading ratio correlation (LRC), the ideal adsorbed solution (IAS) theory, and the real adsorbed solution (RAS) theory based on the Sips equation. In applying the RAS theory, we used the Wilson equation for fitting activity coefficients of metal ions in the ion-exchanger phase. It was proven that basic adsorption models except the LRC model could describe multi-species ion-exchange equilibrium for heavy metals/natural zeolite systems well.     

AuPd bimetal immobilized on amine-functionalized SBA-15 for hydrogen generation from formic acid: The effect of the ratio of toluene to DMF

The volume ratio of toluene to N,N-dimethylformamide (DMF) was adjusted during the amine functionalization of SBA-15 to change the amine content of SBA-15. XPS, FTIR, and TGA analyses indicated that under the experimental synthetic conditions the number of amine groups varies with the ratio of toluene/DMF, and the highest content of amine could be obtained with a volume ratio of toluene/DMF = 3:2. The hydrogen production experiment of formic acid decomposition showed that the hydrogen production efficiency over the Au-Pd-SBA-15-NH₂ catalysts increased with the increase in the surface amine content of the Au-Pd-SBA-15-NH₂. The optimal Au-Pd-SBA-15-NH₂-TD (toluene/DMF = 3:2) catalyst proved to have the smallest Au-Pd bimetal nanoparticle size and exhibited a turnover frequency (TOF) = 631 hours⁻¹ and an activation energy (Ea) = 20.8 kJ · mol⁻¹ at 25°C. The catalytic performance of hydrogen generation from the formic acid was improved due to the synergistic effect between the amine-functionalized SBA-15 and the Au-Pd bimetal (metal-support interactions).     

盐对氨基改性SBA-15吸附Pb2+性能的影响研究

以三嵌段共聚物P123作为模板剂,正硅酸乙酯(TEOS)为硅源,3-氨丙基三乙氧基硅烷(APTES)为偶联剂,采用嫁接法制备氨基化SBA-15-KCl(n),并探究nHCl与nKCl的比对Pb2吸附效率的影响.采用X射线衍射(XRD)、透射电镜(TEM)、红外光谱(FT-IR)和N2吸附-脱附等手段对合成的样品进行表征,通过实验对改性后介孔材料的吸附性能和影响因素进行研究.结果表明:改性后材料对pb2吸附的最佳吸附时间为60 min,体系pH值为5,最佳吸附温度为40℃,当KC1的加入量达到0.0474 mol即nHCl∶nKCl =3∶7时,样品对Pb2+吸附率最佳可在95％左右.     

Characterization of Pt/SBA-15 prepared by the deposition–precipitation method

Mesoporous silica SBA-15 was prepared and loaded with Pt using the deposition–precipitation method (DP). The Pt loaded material was characterized by N₂ sorption, and X-ray diffraction (XRD) at low scattering angles as well as XRD at wide angles, in order to monitor the impact of the metal deposition pathway on the mesoporous texture. After DP the material contains ordered mesoporous silica as well as a fraction appearing as non-ordered amorphous silica. This is most likely caused by the hydrothermal treatment involved in the DP. The material was also characterized using NIR and ²⁹Si MAS NMR spectroscopy. The NIR results of the calcined materials indicate that the silanol groups of SBA-15 may act as anchoring groups for the metallic Pt particles. The NMR spectroscopy data shows that the Pt/SBA-15 sample prepared by the DP method posseses a better short-range regularity of SBA-15 walls as compared to the parent SBA-15. This is suggested to be caused by dissolution and possible re-precipitation of siliceous species.     

石墨烯材料在重金属废水吸附净化中的应用

石墨烯材料具有较大的比表面积、良好的化学稳定性,近年来在环境污染物深度吸附处理方面的应用逐渐引起了人们的关注。本文综述了石墨烯材料在重金属离子的吸附处理方面的研究进展,包括普通石墨烯、氧化石墨烯、功能化石墨烯以及石墨烯复合物等材料;讨论了石墨烯表面功能化修饰对重金属离子吸附性能的影响;分析了各种材料的优点与缺点;提出了需进一步研究的问题,如石墨烯表面功能化修饰的结构-性能关系、石墨烯材料的循环使用以及石墨烯材料对痕量重金属离子的富集灵敏度等问题,指出合成选择性好、富集灵敏度高且可多次循环使用的石墨烯材料,在重金属废水的深度处理中将得到进一步应用。     

氨基改性SBA-15介孔材料的制备及对Pb(Ⅱ)的吸附性能研究

采用水热-后嫁接的方法,分别制备出氨基、二氨基、三氨基改性的介孔二氧化硅吸附剂N-SBA-15、2N-SBA-15、3N-SBA-15.采用X-ray衍射(XRD)、红外光谱(FT-IR)、N2吸附-脱附和扫描电镜(SEM)等方法对材料进行表征.讨论了吸附时间、体系pH值等因素对水中pb2+吸附性能的影响.结果表明:在纯硅SBA-15上嫁接的氨基越多,改性后材料对水中pb2的吸附性能越好,当吸附60 min、体系pH值为5时,材料对水中pb2+的吸附效率最佳,最大吸附率能达到95％左右.     

Removal of heavy metals from water by lignite-based sorbents

Calcium-loaded lignite was used to remove heavy metals from wastewater by ion exchange. The following quantities were determined experimentally: calcium-loading capacity for different types of lignite, selectivity coefficients of Cu, Zn, Pb, Cd, Ni, Co and Fe(II) ions, kinetic sorption dependences and the effect of flow rate on the shape of break-through curves in column experiments. Sorption kinetics was relatively slow and consequently, the sorption dynamics was influenced by this phenomenon. A numerical code taking into account the sorption kinetics was used for modelling, which proved its applicability for scaled-up columns.The process is very efficient especially in the case of low concentrations of pollutants in water, where common methods are either economically unfavourable or technically complicated. This is very often the case of various metals in the environment, and thus the method could be convenient for their removal.     

Dry reforming of methane over Ni/SBA-15 catalysts prepared by homogeneous precipitation method

Ni/SBA-15 catalyst was prepared by homogeneous precipitation method (Ni-HP) and used for dry reforming of methane (DRM). The related characterization results indicated that the Ni particles were highly dispersed with a size range of 2-5 nm. Compared with Ni/SBA-15 catalyst prepared by impregnation (Ni-IM), the reduction temperature of Ni-HP obtained from H2-TPR was greatly improved, suggesting the stronger metal-support interaction. After reacting at 700 °C for 100 h, the CH₄ conversion of DRM over Ni-HP catalyst slightly decreased from 74.5% to 73.8%. While, for the Ni-IM catalyst, the CH₄ conversion dropped from 61.7% to 37.3%. Furthermore, the average particle size of Ni-HP was 3.7 nm and 4.7 nm before and after the long-time stability test, respectively, ascribed to the good anti-sintering property. Although a certain amount of coke was produced, mainly with disorder filamentous carbon of base-growth, the Ni/SBA-15 prepared by homogeneous precipitation exhibited excellent catalytic activity and stability.     

介孔材料SBA-15的改性及其应用研究进展

文章综述了介孔材料SBA-15的改性方法,包括有机功能化改性、杂原子改性和负载活性组分。在此基础上评述了改性SBA-15的应用研究进展,重点介绍了其在催化和吸附领域的应用进展。通过改性引入杂原子或有机官能团或负载活性组分,根据催化反应或吸附分离等性能要求可以有目的地进行功能化调控,可大大拓展其应用范围。     

重金属污染水体植物修复研究进展

综述了近年来国内外水生植物修复重金属污染的研究进展,着重介绍了各类水生植物对重金属的去除效果及植物对不同重金属的选择性吸收特点;讨论了水生植物修复重金属的影响因素;总结分析了目前研究中存在的问题,并提出了今后的发展方向。     

重金属污染水体植物修复研究进展

综述了近年来国内外水生植物修复重金属污染的研究进展,着重介绍了各类水生植物对重金属的去除效果及植物对不同重金属的选择性吸收特点;讨论了水生植物修复重金属的影响因素;总结分析了目前研究中存在的问题,并提出了今后的发展方向。     

水中重金属检测方法的研究进展

对近年来水环境中重金属的检测方法进行了归类、综述,主要介绍了原子吸收光谱法、原子荧光光谱法、溶出伏安法、电感耦合等离子体法、生物酶抑制法、核酸适配体法、免疫分析法在水中重金属的检测应用,分析了各种方法在实际环境中检测的优缺点,并对今后的检测研究进行了展望。     

Adsorption behaviors and mechanism of heavy metals onto attapulgite functionalized by polyamine silane

Pollution from heavy-metal ions has become a major challenge to the global fight against environmental pollution. Given the availability of various low-cost and environmentally friendly adsorbents, adsorption has become the most efficient technology for the removal of heavy metals from water. In this study, attapulgite (ATP) was directly functionalized by coupling with an aminosilane agent. Analysis showed this maneuver provided a suitable adsorbent for the removal of lead ion (Pb²⁺) from an aqueous solution. The effects of several parameters including solution pH, contacting time, adsorbent dosage, and initial Pb²⁺ ion concentration were investigated. Batch sorption results showed that the adsorption process was rapid and over 98% of Pb²⁺ was removed within 30 min at the optimal pH 4.0. The maximum adsorption capacity at 25°C, calculated by the Langmuir isotherm, was 82.17, 78.80, 61.13, and 28.56 mg/g for γ-divinyltriaminepropyl-methyldimethoxylsilane-grafted attapulgite (KH-103-ATP), γ-aminopropyl-methyldiethoxysilane-grafted attapulgite (KH-912-ATP), N-(β-aminoethyl-γ-aminopropyl)-methyl-dimethoxysilane-grafted attapulgite (KH-602-ATP), and ATP, respectively. Moreover, molecular dynamics simulations of adsorption behaviors of heavy-metal ions at attapulgite surfaces (010) modified by aminosilane agents were carried out. Both the PMF value and diffusion coefficient of metal ions suggest that KH-103-ATP owns the highest rate constant and capacity compared with the other two. And the analysis of free energy and results of XPS characterization revealed that Pb²⁺ formed covalent bonds with the nitrogen atom of aminosilane agents.     

水中重金属检测方法的研究进展

对近年来水环境中重金属的检测方法进行了归类、综述,主要介绍了原子吸收光谱法、原子荧光光谱法、溶出伏安法、电感耦合等离子体法、生物酶抑制法、核酸适配体法、免疫分析法在水中重金属的检测应用,分析了各种方法在实际环境中检测的优缺点,并对今后的检测研究进行了展望。