尖晶石型LiMn2O4的水热合成及其锂吸附性能

以Mn(NO3)2, LiOH和H2O2为原料,通过控制水热反应条件直接合成了尖晶石型LiMn2O4纳米线,经酸浸脱锂后得到对Li+具有特殊选择性吸附的离子筛. 用XRD, HRTEM, SAED和共存金属离子的分配系数等手段对产物的晶相结构及吸附性能进行了研究. 结果表明,水热反应条件对前驱体结构有较大影响,前驱体LiMn2O4和离子筛MnO2均为一维纳米线,离子筛对不同金属离子的选择性吸附顺序为Li+>>Ca2+>Mg2+>Na+>K+,说明离子筛具有较高的Li+选择性. Li+的分配系数为16770.63 mL/g,是高温焙烧样品(7917.49 mL/g)的2.12倍,表明一维纳米MnO2离子筛对Li+的选择性吸附性能有显著提高.     

水热法制备Mn_3O_4及其对水中刚果红的吸附研究

用水热法制备Mn3O4材料,通过调整反应中Mn（NO3）2与H2O2溶液的体积比,研究H2O2对反应产物的种类和形貌的影响。结果发现,适量H2O2有助于Mn3O4的生成,但是过量的H2O2会导致产物向纳米线状MnO2的生成。用粉末X射线衍射（XRD）、场发射扫描电镜（FE-SEM）、氮气吸附脱附技术对样品进行了表征,并考察了Mn3O4对水中刚果红的吸附性能。结果表明,水热法制备Mn3O4材料,其比表面积（BET）可达119.31 m2/g;Mn3O4对刚果红的吸附符合准二级动力学方程,平衡吸附数据符合Langmuir吸附等温模型;当Mn（NO3）2与H2O2的体积比为2∶1时,在140℃下水热反应15 h合成的Mn3O4对刚果红的吸附效果最佳,最大吸附量可达81.63 mg/g。     

风化煤在磷矿酸解体系中的吸附特性研究

研究了风化煤对磷矿酸解反应体系中Ca2 、Fe3 、Al3 及H2PO4-的吸附特性.实验表明:风化煤吸附上述4种离子从易到难的顺序及最大吸附量从大到小的顺序均为:Fe3 、Ca2 、Al3 、H2PO4-;吸附等温方程均符合Langmuir方程,且相关性显著.为探讨风化煤对磷矿转化率的影响和生产生态型磷肥提供了理论基础.     

水中硝基苯在柱撑膨润土上的吸附行为

在［OH^-］/［Al³⁺］=2.4的反应条件下,利用Al³⁺与碱液反应制备出Keggin离子,并由此制备出了无机、无机-有机柱撑膨润土,XRD-衍射数据表明,经柱撑后的膨润土层间距明显增大,达1.9 nm以上.研究了硝基苯在4种改性膨润土上的吸附行为,结果表明：经柱撑处理后的膨润土吸附能力明显大于钠基土,其吸附动力学行为遵循Bingham方程和Langmuir方程所描述的规律,平衡吸附量q_e与平衡浓度C_e之间的关系符合Freundlich和Langmuir等温吸附方程,吸附表现为放热的物理吸附和有机质的分配作用.     

偏钛酸型离子交换剂的制备及其对锂的富集性能

以钛酸四丁酯和乙酸锂为原料,采用醇盐水解溶胶-凝胶法制备了偏钛酸锂前驱体,经酸浸脱锂后得可选择性富集锂的离子交换剂,对前驱体及离子交换剂的晶相及选择性富集能力进行了研究.结果表明,固液比为4 g/L,p H=12.8,纯Li溶液初始浓度200 mg/L,35℃恒温振荡条件下吸附3 h,Li2Ti O3(H)对Li+吸附容量为33.5345 mg/g.吸附过程可用准二级动力学模型和Langmuir吸附等温模型描述,属自发放热吸附反应.     

无机锰吸附材料的制备及其锂离子的吸附性能

以氢氧化锂为原料,通过控制无机锰吸附材料合成反应条件制备了尖晶石型的LiMn2O4离子筛前驱体,经酸浸脱锂后获得对Li+具有特殊选择性吸附的尖晶石型离子筛。对无机锰吸附材料进行了XRD、SEM、BET表征,测定了离子筛对纯锂溶液和卤水中锂的吸附容量。结果表明,当离子筛制备体系的原料锂锰物质的比为0.5、800 ℃下反应15 h时,产品为近纯尖晶石型晶体,且具有较大比表面积。吸附实验表明,该离子筛在碱性含锂溶液中对Li+具有吸附性能,且吸附容量随着溶液pH和温度的升高而增大,在pH=13的纯锂溶液中最大吸附量可达32.251 mg/g,并在30 h达到吸附平衡。该吸附材料循环利用8次后,吸附量保持在18 mg/g以上,在西藏龙木错卤水中,对锂的吸附量达到11.273 mg/g。吸附过程符合伪二级动力学,表明吸附过程主要为化学吸附,且离子交换反应的控制步骤是颗粒扩散控制（PDC）。     

高氟碘溶液絮凝吸附脱氟的动力学研究

对絮凝净化富碘吸收液中氟吸附动力学过程进行了研究.实验结果表明,复合Al(OH)3胶体对碘溶液中6.00×10-4～7.50×10-4浓度的氟离子吸附平衡满足Freundlich方程,实验给出了F-最大吸附量及吸附剂最佳用量.吸附分快慢反应2个过程:(1)在前3 h内复合Al(OH),3胶体对氟的吸附量占整个过程的70%～90%;(2)慢反应在3～24 h内近于完成.Modifide Freundlich方程能较好的关联快速吸附阶段,First-order kinetics能很好地描叙慢速反应阶段.     

新生MnO2对甲基红的吸附性能研究

以MnSO4和KMnO4为主要原料制备出新生MnO2,并用新生MnO2对甲基红废水进行吸附实验,研究了甲基红废水的pH值、新生MnO2的用量和吸附时间等因素对吸附性能的影响。实验结果表明,在室温条件下,当溶液中甲基红质量浓度为100 mg/L、处理量为100 mL、pH值为4、吸附3 h、新生MnO2用量为40 mg时,甲基红的脱色率可达98.2%。     

木粉基吸附剂的制备及性能研究

制备并研究了木粉基重金属离子吸附剂对金属离子的吸附性能.结果表明,吸附剂对Pb2 、AS 、Cu2 、Mn2 4种离子的饱和吸附容量分别达89.46、73.92、22.25 mg/g和21.8 mg/g,是木粉接枝共聚前吸附容量的4～10倍.吸附剂对所研究的金属离子的吸附特征可用Freundlich方程近似描述.找到了Pb2 、Ag 、Cu2 、Mn2 适宜吸附的pH范围,再生实验表明吸附剂经3次再生之后仍保持较高的吸附容量.     

硅酸锂的制备及高温吸附二氧化碳的研究进展

主要对影响Li4Si O4高温吸附CO2的因素,包括Li4Si O4的合成方法、金属元素的掺杂以及吸附过程中的反应条件进行了分析。当前Li4Si O4的主要合成方法有高温固相法、溶胶-凝胶法、沉淀法、柠檬酸络合法、凝胶固相法,不同的合成方法制备的Li4Si O4吸附CO2的性能不同。掺杂适量的金属元素可以提高Li4Si O4吸附CO2的速率,过量地掺杂会降低其吸附量和吸附速率,掺杂不同的金属元素(钾、钠、钛、铁、铝等)对其吸附CO2性能的影响程度不同。合适的吸附温度可以提高反应速率和吸附容量,适当增大CO2分压可以提高反应速率,并且添加适量水蒸气能够提高吸附性能。     

Adsorption equilibrium of copper ion and phenol by powdered activated carbon, alginate bead and alginate-activated carbon bead

The adsorption equilibrium characteristics for single and binary components of copper ion and phenol onto powdered activated carbon, alginate bead and alginate-activated carbon (AAC) bead were studied. Adsorption equilibrium data of phenol and copper ion onto the adsorbents could be represented by Langmuir equation. The adsorption capacity of Cu²⁺ onto different adsorbents was in the following order: alginate bead > AAC bead > powdered activated carbon (PAC). On the other hand, that of phenol was: PAC > AAC bead > alginate bead. Multi-component equilibrium data were correlated by three different models. Among them the ideal adsorbed solution theory (IAST) gave the best fit to our data. And the adsorption amount of Cu²⁺ onto AAC bead was greater than that of phenol in the binary components.     

Adsorptive Removal of Rhodamine B with Activated Carbon Obtained from Okra Wastes

This study aimed at preparing and optimizing an activated carbon (OAC) obtained from dry okra wastes by chemical activation with zinc chloride. Also, Rhodamine B removal performance from aqueous solution was analyzed by using this optimized activated carbon. The characterization of the resultant activated carbon, with a high surface area of 1044?m²/g, was carried out using thermogravimetric analysis, Brunauer–Emmett–Teller model, t-plot, N₂ adsorption/desorption isotherms, density functional theory, elemental analysis, Fourier transform infrared spectroscopy, scanning electron microscopy, and the point of zero charge. Furthermore, the effects of operating conditions (contact time, initial concentration, adsorbent dosage, temperature, and pH) on Rhodamine B adsorption onto OAC were investigated. Langmuir model was determined to be the best adsorption process, and the maximum adsorption capacity was calculated to be 321.50?mg/g at 25°C. Also, the intraparticle diffusion and boundary layer diffusion were involved in RhB adsorption onto OAC. Moreover, OAC adsorption curves of Rhodamine B followed pseudo second-order model. At 25°C, Gibbs free energy, enthalpy, and entropy obtained from thermodynamic studies were determined to be ?27.87?kJ/mol, 13.03?kJ/mol, and 0.15?kJ/mol K, respectively. These thermodynamic values revealed that Rhodamine B adsorption onto OAC was feasible, endothermic, physical, and spontaneous.     

Removing H2S from Biogas Using Sorbents for Solid Oxide Fuel Cell Applications

Desulfurization of biogas is essential for its application in solid oxide fuel cells. The influence of CH₄, CO₂, H₂, and O₂ as well as the effect of moisture onto desulfurization performance of an activated carbon, an adsorbent based on a CuO‐MnO mixture, and a zeolite adsorbent were analyzed. The use of moisturized gas had no negative influence on the H₂S adsorption performance of activated carbon. The CuO‐MnO sorbent showed the best performance, but the presence of moisture had a negative influence. The performance of zeolite dropped for three gas mixtures, while for two other mixtures moisture had little to no influence on H₂S adsorption performance.     

高温下L12ZrO3吸附CO2的研究进展

Li2ZrO3能够在高温下吸附CO2,并且其吸附效率高、速度快、稳定性好且能够重复利用。作者对近年来有关Li2ZrO3材料吸附CO2的研究进行了分析,比较了Li2ZrO3的各种合成方法的优缺点,介绍了Li2ZrO3吸附CO2的反应机理,分析了影响Li2ZrO3吸附CO2的吸附量及速率的各种因素,并对高温下吸附CO2的Li2ZrO3材料的前景进行了展望。     

锂离子电池正极材料技术进展

概述了国内外近30 a有关锂离子电池正极材料的研究进展以及笔者在锰系正极材料方面的研究结果; 比较了几种主要正极材料的性能优缺点;阐明了正极材料发展方向。近期镍钴锰酸锂三元材料将逐步取代钴酸锂,而改性锰酸锂和镍钴锰酸锂三元材料以及两者的混合体将在动力型锂离子电池中获得广泛使用。在未来5~10 a,高容量的层状富锂高锰型正极材料或许会是下一代锂离子电池正极材料的有力竞争者。     

均匀设计优化油页岩原矿吸附去除水中铜离子

采用均匀设计优化实验方案并确定了油页岩吸附水中 Cu2+的最优条件.设定吸附时间(X1)、初始浓度(X2)、吸附剂投加量(X3)、溶液 pH(X4)和水浴温度(X5)为5个影响因子,通过均匀设计设定了5因素12×6×6×6×3水平的实验.逐步回归分析表明,对油页岩吸附 Cu2+有显著影响的因素依次是 pH、吸附时间、吸附剂投加量和吸附温度.初始浓度对吸附效果起负作用.极大值回归分析确定吸附的最佳条件为 pH=5.15, Cu2+初始浓度为28.49 mg/L,吸附剂投加量为0.28 g,吸附时间为162 min,吸附温度32.5℃.在此条件下,实测 Cu2+的吸附率达99%.     

K-, CeO2-, and Mn-promoted Ni/Al2O3 catalysts for stable CO2 reforming of methane

Reforming of methane with carbon dioxide into syngas over Ni/γ-Al₂O₃ catalysts modified by potassium, MnO and CeO₂ was studied. The catalysts were prepared by impregnation technique and were characterized by N₂ adsorption/desorption isotherm, BET surface area, pore volume, and BJH pore size distribution measurements, and by X-ray diffraction and scanning electron microscopy. The performance of these catalysts was evaluated by conducting the reforming reaction in a fixed bed reactor. The coke content of the catalysts was determined by oxidation conducted in a thermo-gravimetric analyzer. Incorporation of potassium and CeO₂ (or MnO) onto the catalyst significantly reduced the coke formation without significantly affecting the methane conversion and hydrogen yield. The stability and the lower amount of coking on promoted catalysts were attributed to partial coverage of the surface of nickel by patches of promoters and to their increased CO₂ adsorption, forming a surface reactive carbonate species. Addition of CeO₂ or MnO reduced the particle size of nickel, thus increasing Ni dispersion. For Ni–K/CeO₂–Al₂O₃ catalysts, the improved stability was further attributed to the oxidative properties of CeO₂. Results of the investigation suggest that stable Ni/Al₂O₃ catalysts for the carbon dioxide reforming of methane can be prepared by addition of both potassium and CeO₂ (or MnO) as promoters.     

Evaluation of humic acid, chromium (VI) and TiO2 ternary system in relation to adsorptive interactions

Batch adsorption studies were carried out for the assessment of the adsorptive interactions of the system composed of humic acid, Cr(VI) and TiO₂. These were preceded by a thorough investigation of the effect of the chromium ion concentration on the adsorption of humic acid onto TiO₂. The adsorption equilibrium of total chromium, humic acid, and titanium dioxide in water were examined separately and in all combinations in order to distinguish the effects based on the interaction of the components. The adsorption data for the binary system as well as the ternary system were modeled with a simple Freundlich model and the model parameters were compared in terms of Cr(VI) and humic acid as expressed by Color₄₃₆ (color forming moieties) and UV₂₅₄ (UV absorbing centers) parameters.

In binary systems composed of Cr(VI) and TiO₂ no direct relationship could be assessed between adsorption capacity values (K_F) and changes in chromium ion concentration. Chromium ion and humic acid interactions were followed by UV-Vis spectra. A minor change irrespective of added chromium ion concentration was observed for Color₄₃₆ and UV₂₅₄ parameters of humic acid (<5%). However, a significant alteration was observed at 365 nm wavelength indicating the formation of chromate esters. In ternary systems comprising humic acid, Cr(VI) and TiO₂, increasing Cr(VI) concentration five-fold did not cause drastic changes in the adsorption capacity values in terms of Cr(VI) concentration. On the other hand, the adsorption capacity values for color forming moieties as well as for UV absorbing centers of humic acid exhibited a decreasing trend with respect to increasing chromium ion concentration.     

Large scale fabrication of porous boron nitride microrods with tunable pore size for superior copper (II) ion adsorption

Herein, large scale fabrication of porous boron nitride (BN) microrods has been achieved via a facile process, which involves the synthesis of melamine diborate precursors and subsequent thermal treatment process. The fabrication can be scaled up to ultra-large scale which is limited by the furnace. The characterization results show that the as-obtained products are porous BN microrods with diameters in the range of ten to tens of micrometers and length of a few millimeters, respectively. The specific surface area and porosity of these porous BN microrods are tunable by adjusting the synthesis processes of precursors. A highest specific surface area of 653.66?m²/g is obtained for the sample of BN-4, corresponding to the differential pore volume of 0.289?cm³/(g?nm) and pore size of about 1.928?nm. Further measurement shows that the as-obtained porous BN microrods possess excellent copper ion adsorption property with a highest adsorption capacity of 365.4?mg/g. This adsorption capacity is superior to those of most copper ion adsorbents reported in recent literature. The high copper ion adsorption capacity combining with the unique properties of hexagonal BN makes them promising candidates for copper ions adsorption in practical wastewater treatment.