ZSM-5沸石分子筛的高压吸附储氢特性

研究了ZSM-5沸石分子筛对氢的超临界吸附特性．结果表明,在77K／5MPa、195K／7MPa、293K／7MPa条件下,ZSM-5沸石分子筛的储氢质量分数分别为1．97％、0．65％和0．4％．用Clausius-Clapeyron方程求得的等量吸附热（3．8kJ／mol）与吸附量无关,表明该分子筛是一种表面势场均匀的吸附剂．将表面过剩吸附理论与描述Ⅰ型等温线的诸理论模型结合,分析了超临界吸附等温线,发现基于Toth方程的等温线模型在整个实验范围内与实验数据吻合较好,由该模型计算出的氢吸附相密度在77K达到55．6kg／m^3．根据回归参数讨论了超临界条件下氢在微孔沸石分子筛中的吸附机理,确认了氢在微孔沸石分子筛中的吸附为物理吸附．     

Mg-Al-Ce水滑石吸附去除水中的硼

用共沉淀法成功制备了镁铝铈水滑石(Mg-Al-Ce-HT), 采用不同分析手段对材料进行表征。通过静态吸附实验研究了Mg-Al-Ce-HT的吸附效率与初始pH、吸附剂剂量、初始硼酸浓度和接触时间的关系。当pH小于8.0时, 溶液的pH对硼吸附几乎没有影响, 当pH超过8.0时, 吸附容量降低。吸附剂的最佳用量为200 mg, 最大吸附容量为32.52 mg·g ^-1。 硼去除量在160 min内达到平衡。吸附等温线表明吸附过程是一个非自发的吸热过程。吸附数据与Langmuir模型拟合良好, 表明吸附是单层吸附。     

腐植酸保水剂吸附氮磷特性研究

以硫酸铵代替氮、以磷酸氢二钾代替磷,采用静态吸附法测定自制腐植酸保水剂吸附对氮／磷的吸附量;改变铵根离子和磷酸根离子浓度绘制吸附等温线,并采用几种模型对等温吸附数据进行拟合,确立了其等温吸附模型。结果表明：自制腐植酸保水剂对铵根离子或磷酸根离子具有很大的吸附容量,磷酸氢二钾浓度小于18g/L、硫酸铵浓度小于10g／L的范围内,吸附量随浓度的升高快速增加。该保水剂对硫酸铵的等温吸附在0-10g／L范围内较好的符合平方曲线模型,而磷酸氢二钾浓度在0-18g／L范围内对磷酸根的吸附更好的符合直线模型。     

蜂窝状离子印迹壳聚糖/ZSM-5复合泡沫对U(Ⅵ)的吸附特性

工业含铀废水排放导致的放射性污染严重危害环境安全和人体健康。文中制备了蜂窝状离子印迹壳聚糖/ZSM-5(ICZ)复合泡沫,用于选择性吸附U(Ⅵ)。结果表明,不同原料配比制备的ICZ泡沫中,ICZ-2对U(Ⅵ)吸附效果最佳,是由于其兼具发达的蜂窝状结构和丰富的功能基团。与非离子印迹吸附剂比较,离子印迹吸附剂ICZ-2能选择性识别目标离子,因此具有更高的吸附容量和选择性。吸附等温线符合Langmuir模型,表明为均相单分子层吸附,吸附容量达280.09 mg/g;吸附动力学符合拟二级模型,表明化学吸附是控速步骤。ICZ-2对U(Ⅵ)的吸附以功能基配位络合为主要机理。ICZ-2吸附容量高、吸附速率快、吸附选择性好,有望用于含铀废水处理。     

新型特效Na离子吸附剂Li1+xAlxTi2-x(PO4)3的制备和性能研究

采用高温固相法合成了新型特效Na离子吸附剂Li1＋xAlxTi2-x（PO4）3．通过对不同条件下合成的样品XRD、SEM及其吸附性能的研究表明，少量Al的加入未影响到LiTi2（PO4）3的晶体结构，但使Li1＋xAlxTi2-x（PO4）3对Na离子产生了特效吸附作用．当x=0．4时，在pH值为10．0—11．0条件下，Li1＋xAlxTi2-x（PO4）3的吸附容量达到11．76mg／g．另外，本文对材料的激光拉曼光谱和红外光谱进行了研究和指认．     

硫脲改性活性炭及吸附金性能研究

为了改善活性炭吸附性能,利用硫脲溶液在超声波辅助条件下对活性炭进行改性,探究了不同改性及吸附条件下的吸附金的效果,利用场发射扫描电镜(SEM)及傅里叶红外光谱仪(FT-IR)对改性前后的活性炭孔结构和表面特性进行表征。结果表明,最佳改性条件为3 mol/L的硫脲溶液,温度为95～100℃,时间为3 h;吸附环境适宜pH值为2～2.5,投入0.5 g改性炭,吸附时间为1.5 h,吸附率达到97%。表征发现,改性后活性炭孔结构明显,比表面积增大。硫脲的加入改变了原有基团的波谱峰,同时产生了新基团,如—NH_2、■、C—H、■等,增强炭的吸附。改性炭的吸附等温线符合Langmuir与Freundlich等温线模型,表明改性炭的吸附模式是以单分子层吸附为主与多层吸附共同作用的吸附模式,拟合后得到的饱和吸附容量为0.208 mmol/g,实际得到的饱和吸附容量为(0.194 mmol/g),吸附效果较好。     

氯化钠改性5A分子筛吸附剂的实验研究

采用氯化钠浸渍法改性5A分子筛，并吸附净化泥磷制取次磷酸钠产生的含PH。气体，选择吸附效率和吸附容量进行吸附剂吸附效果的判定。主要考察了氯化钠浸渍液的浓度、吸附剂的干燥温度、焙烧温度对吸附效果的影响，确定了最适宜的吸附剂制备条件：在浸渍液浓度0．3mol／L、干燥温度110~C、焙烧温度为300℃的条件下，吸附容量为2...     

Synthesis and adsorption of montmoriilonite/sodium alginate graft poly （acrylic acid） superabsorbent composite

以过硫酸胺（APS）为引发剂,N,N-亚甲基双丙烯酰胺（MBA）为交联剂,采用插层聚合法制备了蒙脱土／海藻酸钠接枝丙烯酸（MMT／SA—g—PAA）高吸水性复合物。通过红外光谱（FT—IR）、扫描电镜（SEM）、热重分析（TGA）对MMT／SA—g—PAA的结构和性能进行了表征。研究了MMT／SA-g—PAA对重金属离子的吸附性能,结果表明室温下MMT／SA—g-PAA对Pb2＋、Cu2＋、Ni2＋的最大吸附量分别为968．9、231．0及236．Omg／g,其中对Pb2＋和Cu计的吸附符合Langmuir吸附模型,而对Ni2＋的吸附符合Freundlich吸附模型。     

微波辐射合成MIL-101多孔材料及其对苯的吸附热

采用微波辐射法合成MIL-101多孔材料,探讨了反应温度对材料合成的影响。同时对MIL-101进行XRD测试以及孔结构和比表面积分析,采用重量法测定了288、298和308K条件下苯在MIL-101多孔材料上的吸附等温线,并估算MIL-101对苯的等量吸附热。结果表明,MIL-101多孔材料的比表面积达2089.2m2/g,苯在MIL-101上的吸附等温线呈I型等温线,与Langmuir模型吻合很好,表明吸附主要为微孔吸附;随着温度的升高,MIL-101对苯的平衡吸附量逐渐下降,说明苯在MIL-101多孔材料的吸附以物理吸附为主。在T=298K,p/p0=0.5时,苯在MIL-101多孔材料上的吸附量为9.44mmol/g,远高于同等条件下普通活性炭和活性炭纤维对苯的吸附容量;苯在MIL-101上的等量吸附热为45.4～41.6kJ/mol的范围,其等量吸附热随着表面吸附量的增加变化幅度不大,与活性炭纤维相比,MIL-101的表面吸附自由能分布比较均匀。     

污泥灰对Cd(Ⅱ)和Ni(Ⅱ)的吸附作用研究

在静态条件下,以改性城市污泥为吸附剂,研究了污泥灰(MSSA)对重金属离子的吸附性能,着重探讨了改性污泥灰去除工业电镀废水中重金属离子Cd(Ⅱ)、Ni(Ⅱ)的适宜条件.结果表明,pH值是影响污泥灰对重金属离子吸附的重要因素,镉(Ⅱ)、镍(Ⅱ)吸附的最佳pH值为6.0和6.5;当吸附剂最佳用量为10g/L时,Cd(Ⅲ)、Ni(Ⅱ)的吸附容量分别达到1.21mg/g和1.02mg/g;吸附等温线可以用Freundilich和Langmuir模型描述,吸附过程基本符合Langmuir和Freundilich吸附等温式.该吸附剂吸附性能优越,可有效地去除废水中的相关金属离子.     

杂原子聚合物冠醚研究Ⅲ.多胺交联甘油双缩水甘油醚树脂的合成及其吸附性能

合成了三乙烯四胺交联的甘油双缩水甘油醚树脂,并研究了该树脂对Cu2+、Ni2+、Zn2+、Co2+的静态吸附性能和吸附机理.结果表明,该树脂对Zn2+、Co2+的吸附是单一吸附机理,而对Cu2+、Ni2+的吸附则为多重吸附机理,对4种离子的等温吸附过程均符合Freundlich方程.对Cu2+、Ni2+、Zn2+、Co2+的吸附容量可分别达0.61、0.32、0.06和0.23 mmol／g.     

Synthesis of mesoporous aluminophosphates impregnated with metals and their application in gas oil desulphurization by adsorption

Mesoporous materials based on aluminophosphates and silicates have been synthesised and impregnated with different loadings of transition metals such as Ag, Cu and Ni. These materials have been characterised and tested as selective adsorbents for the desulphurization of light cycle oil (LCO) by liquid adsorption. The polarity of the adsorbent matrix showed a positive effect on desulphurization, leading the impregnated aluminophosphates to higher adsorption capacities than the silicates. Among the transition metals tested, Ag-impregnated materials showed the best results followed by Cu and Ni. The aluminophosphate synthesised using pluronic F-127 block copolymer impregnated with a 5% of Ag (MFAP-5Ag) presented the best adsorption results with a maximum adsorption capacity of 11.36 mg S/g of adsorbent (equilibrium experiments), and breakthrough and saturation capacities of 4.25 mgS/g and 7.06 mgS/g, respectively (dynamic experiments).     

Preparation of a novel zwitterionic graphene oxide-based adsorbent to remove of heavy metal ions from water: Modeling and comparative studies

A novel zwitterionic graphene oxide-based adsorbent was first synthesized in a multistep procedure including the successive grafting of bis(2-pyridylmethyl)amino groups (BPED) and 1,3-propanesultone (PS) onto graphene oxide (GO) sheets. Then, the as-prepared materials were used as adsorbent for the removal of metal ions from aqueous solutions. The influence of solution pH, contact time, metal ion concentration, and temperature onto the adsorption capacity of the zwitterionic GO-BPED-PS adsorbent was investigated and compared with the GO-BPED adsorbent. In particular, it was shown that the maximum adsorption capacities of the GO-BPED-PS adsorbent were as high as 4.174 ± 0.098 mmol.g^?1 for the Ni(II) ions and 3.902 ± 0.092 mmol.g^?1 for the Co(II) ions under optimal experimental conditions (metal ion concentration = 250 mg.L^?1, pH = 7 and T = 293 K). In addition, the adsorption behaviors of Ni(II) and Co(II) ions onto both the GO-BPED and GO-BPED-PS adsorbents fitted well with a pseudo-second-order kinetic model and a Jossens isotherm model. Moreover, adsorption thermodynamics of Ni(II) and Co(II) ions have been studied at various temperatures and confirmed the exothermic adsorption nature of the adsorption process onto the GO-BPED-PS adsorbent. Furthermore, the zwitterionic GO-BPED-PS adsorbent retained good adsorption properties after recycling 18 times which is much better than the conventional adsorbents.     

Novel zwitterionic inorganic-organic hybrids: synthesis of hybrid adsorbents and their applications for Cu2+ removal

A series of zwitterionic hybrid adsorbents were prepared via the ring-opening polymerization of pyromellitic acid dianhydride (PMDA) and N-[3-(trimethoxysilyl)propyl] ethylene diamine (TMSPEDA), and a subsequent zwitterionic process as well as sol-gel reaction. Their applications for Cu(2+) removal by adsorption were performed. FTIR spectra confirmed the step products. TGA revealed that the initial decomposition temperature (IDT) of these zwitterionic hybrid adsorbents could arrive at near 150°C. DSC showed that T(g) values decreased with an increase in PMDA content in the hybrid matrix. Ion-change capacity (IEC) revealed that the cation-exchange capacities (CIECs) and anion-exchange capacities (AIECs) of these hybrid adsorbents were within the range of 9.13-11.49 and 4.97-6.28 mmol g(-1), respectively. Meanwhile, the CIECs and AIECs exhibit an opposite change trend as PMDA content increases. Adsorption experiment indicated that their adsorptions for Cu(2+) ions followed Lagergren second-order kinetic model, surface adsorption and intraparticle diffusion mechanisms might be the major process. These findings demonstrated that they are promising absorbents for the separation and recovery of Cu(2+) ions from contaminated water.     

Low-cost adsorbents for heavy metals uptake from contaminated water: a review

In this article, the technical feasibility of various low-cost adsorbents for heavy metal removal from contaminated water has been reviewed. Instead of using commercial activated carbon, researchers have worked on inexpensive materials, such as chitosan, zeolites, and other adsorbents, which have high adsorption capacity and are locally available. The results of their removal performance are compared to that of activated carbon and are presented in this study. It is evident from our literature survey of about 100 papers that low-cost adsorbents have demonstrated outstanding removal capabilities for certain metal ions as compared to activated carbon. Adsorbents that stand out for high adsorption capacities are chitosan (815, 273, 250 mg/g of Hg(2+), Cr(6+), and Cd(2+), respectively), zeolites (175 and 137 mg/g of Pb(2+) and Cd(2+), respectively), waste slurry (1030, 560, 540 mg/g of Pb(2+), Hg(2+), and Cr(6+), respectively), and lignin (1865 mg/g of Pb(2+)). These adsorbents are suitable for inorganic effluent treatment containing the metal ions mentioned previously. It is important to note that the adsorption capacities of the adsorbents presented in this paper vary, depending on the characteristics of the individual adsorbent, the extent of chemical modifications, and the concentration of adsorbate.     

Adsorption thermodynamic and kinetic studies of trihalomethanes on multiwalled carbon nanotubes

Multiwalled carbon nanotubes (MWCNTs) were purified by mixed HNO3/H2SO4 solution and were employed as adsorbents to study adsorption kinetics and thermodynamics of trihalomethanes (THMs) from chlorinated drinking water. The amount of THMs adsorbed onto CNTs decreased with a rise in temperature and high adsorption capacities were found at 5 and 15 degrees C. Under the same conditions, the purified CNTs possess two to three times more adsorption capacities of CHCl3, which accounts for a major portion of THMs in the chlorinated drinking water, than the commercially available PAC suggesting that CNTs are efficient adsorbents. The thermodynamic analysis revealed that the adsorption of THMs onto CNTs is exothermic and spontaneous.     

Porous carbon nitrification process optimization for enhanced benzene adsorption

Benzene is one of the aromatic hydrocarbons co-absorbed with acid gases during amine scrubbing that contribute to deactivation of catalyst in the Claus process. The present work attempts to modify the porous carbon surface through nitrogen group functionalization utilizing melamine as the nitrogen source, adopting Design of Experiments (DOE) with concentration of melamine, duration of impregnation and temperature of impregnation being the process variables, while BET surface area was the response variable. The surface modified samples were subjected to benzene adsorption. The optimal nitrogen content that had minimal pore damage was found to be less than 4.3%, with concentration of melamine being the most significant variable. Surface nitrogen functionalization reduced the surface area whereas the benzene adsorption capacity increased. Benzene adsorption capacity as high as 14.72 mmol/g was recorded at 45°C at a pressure of 235 mbar. Such high adsorption capacities have not been reported in open literature and the nitrogen functionalization augmented the adsorption to the tune of 20 to 30% at a pressure of 100 mbar, and only up to 10 to 15% at higher pressures. The adsorption isotherms as well as the kinetics of adsorption were modelled using the well-known popular models. Further, successful regeneration of the surface modified adsorbents were ensured through adsorption/desorption cycle experiments.     

醇胺改性氧化石墨烯的制备及二氧化硫吸附性能

固体吸附剂在烟道气脱硫方面具有很大的潜力。以氧化石墨烯(GO)为基底材料,通过乙醇胺(MEA)、二乙醇胺(DEA)和三乙醇胺(TEA)对氧化石墨烯进行改性,得到了GO-MEA、GO-DEA和GO-TEA三种用于吸附SO_2的固体吸附剂。利用扫描电镜(SEM)、傅里叶变换红外光谱(FT-IR)、X射线光电子能谱(XPS)、能量色散X射线能谱(EDS)、元素分析(EA)等手段对其进行表征,并采用称重法测定了醇胺改性氧化石墨烯对SO_2气体的吸附性能。结果表明,醇胺改性氧化石墨烯对SO_2的吸附性能相比未改性氧化石墨烯有较大提高,其中GO-DEA的SO_2吸附性能最好,15h后平衡吸附量达到188.5mg/g。在130℃、真空条件下进行解吸,经过五次循环之后吸附量依然保持在165.3mg/g。     

Effective removal of Zn (II) ions from aqueous solution by the magnetic MnFe2O4 and CoFe2O4 spinel ferrite nanoparticles with focuses on synthesis,characterization, adsorption,and desorption

In this study, the MnFe₂O₄ and CoFe₂O₄ spinel ferrites nanoparticles were synthesized via a practical co-precipitation route to investigate the zinc removal from aqueous solution. The synthesized magnetic adsorbents were characterized by XRD, VSM, FE-SEM, BET, EDS, and DLS analyses. The synthesized adsorbents had a diameter range of 20–80 nm. The specific surface areas of adsorbents were found to be 84.5 and 50.4 m²/g for MnFe₂O₄ and CoFe₂O₄, and the saturation magnetization were 61.39 and 37.54 emu/g, respectively. The effects of initial pH, contact time, metal ion concentration, and temperature on Zn (II) adsorption were precisely investigated. These nanoparticles could remove Zn (II) by following the Langmuir isotherm model at optimum pH = 6, with the high adsorption capacities of 454.5 and 384.6 mg/g for MnFe₂O₄ and CoFe₂O₄, respectively. The results of kinetics studies were well fitted by pseudo-second-order, with the determination coefficients of 0.999 for both adsorbents. The thermodynamics studies showed that the zinc (II) adsorption was an exothermic and spontaneous process. Furthermore, the reusability and the desorption capability of adsorbents were also investigated.     

Adsorption characteristics of haloacetonitriles on functionalized silica-based porous materials in aqueous solution

The effect of the surface functional group on the removal and mechanism of dichloroacetonitrile (DCAN) adsorption over silica-based porous materials was evaluated in comparison with powdered activated carbon (PAC). Hexagonal mesoporous silicate (HMS) was synthesized and functionalized by three different types of organosilanes (3-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane and n-octyldimethysilane). Adsorption kinetics and isotherm models were used to determine the adsorption mechanism. The selective adsorption of five haloacetonitriles (HANs) in the single and mixed solute systems was also studied. The experiments revealed that the surface functional groups of the adsorbents largely affected the DCAN adsorption capacities. 3-Mercaptopropyl-grafted HMS had a high DCAN adsorption capacity compared to PAC. The adsorption mechanism is believed to occur via an ion-dipole electrostatic interaction in which water interference is inevitable at low concentrations of DCAN. In addition, the adsorption of DCAN strongly depended on the pH of the solution as this related to the charge density of the adsorbents. The selective adsorption of the five HANs over PAC was not observed, while the molecular structure of different HANs obviously influenced the adsorption capacity and selectivity over 3-mercaptopropyl-grafted HMS.