农业废弃物香芋柄对含Mn2+废水的吸附

以废弃香芋柄作为新型生物吸附剂,通过静态吸附实验,研究了pH、温度、吸附时间、Mn2+初始浓度等因素对香芋柄吸附Mn2+的影响,分析了吸附过程的热力学、动力学和等温吸附规律. 结果表明,溶液初始pH=4,香芋柄用量6 g/L,30℃下吸附60 min,溶液中Mn2+吸附去除率达90.79%以上,吸附容量高达18.16 mg/g. 应用Langmuir和Freundlich模型描述香芋柄对Mn2+的吸附过程,结果显示Freundlich吸附等温线拟合效果更好. 吸附动力学实验数据符合准二级动力学模型. 计算得到热力学参数DG<0, DH>0, DS>0,表明该吸附过程是自发和吸热的过程.     

黑曲霉对水中Ni~(2+)的吸附研究

用黑曲霉作为生物吸附剂对水中Ni2+进行吸附去除研究。考察了pH、温度、吸附时间及共存离子等因素对黑曲霉吸附Ni2+效果的影响。实验结果表明,当溶液pH为7,菌体对Ni2+的吸附效果较好,去除率可达85%以上。随着吸附温度升高,黑曲霉对Ni2+吸附去除率也随着升高。对等温吸附数据用Langlnuir和Freundlich模型进行拟合,结果表明,Langmuir方程更适合描述黑曲霉对Ni2+的吸附。对吸附动力学的研究表明,黑曲霉对Ni2+吸附过程符合二级动力学模型,相关系数大于0.99。     

脱硫渣吸附剂对Cu2+的吸附动力学和热力学

以钢铁冶炼厂干法烟气脱硫产生的脱硫渣为吸附主原料制备了除铜吸附材料。探讨了吸附剂样品对含铜废水中Cu2+吸附效果;用3种动力学经验方程和两种热力学模型对吸附过程进行了动力学和热力学表征。结果表明:Cu2+的最佳吸附条件是pH值为8～9,吸附时间为1.5 h以内。热力学和动力学过程拟合结果表明,吸附的动力学过程更符合准二级动力学速率方程,而Freundlich型吸附等温线模型能较好地模拟吸附剂样品对废液中Cu2+吸附的热力学过程。热力学和动力学分析结果表明,脱硫渣吸附剂对Cu2+的吸附并不是单层吸附,同时存在物理和化学吸附过程。     

松果对废水中Cu~(2+)、Pb~(2+)、Zn~(2+)的吸附特性研究

以松果作为吸附剂进行了去除废水中Cu2+、Pb2+、Zn2+的吸附及解吸试验,研究了溶液pH值、吸附剂投加量、反应时间、溶液初始浓度对吸附效果的影响,以及不同pH值对达到吸附平衡的松果的解吸影响。结果表明:当pH值为5.0～5.5,Cu2+、Pb2+、Zn2+初始质量浓度约为25 mg/L时,吸附剂的最佳投加量分别为3、1.5、3 g/L,去除率分别为55.32%、86%、39.96%。3种重金属离子的吸附动力学方程符合Lagergren准二级动力学方程,R2均大于0.998。等温吸附研究表明:Freundlich方程能较好地描述Cu2+的等温吸附过程,Langmuir方程则能更好地描述Pb2+和Zn2+的吸附过程,用Langmuir方程拟合等温吸附数据得出松果对Cu2+、Pb2+、Zn2+的最大吸附量分别为9.10、31.65和9.60 mg/g。强酸是一种理想的Cu2+和Zn2+解吸剂。     

天然海泡石对染料酸性蓝62的吸附研究

研究了酸性蓝62在天然海泡石上的吸附动力学及热力学特性,探讨了初始p H值、温度等因素的影响。结果表明:吸附动力学符合Lagergren二级吸附速率方程;在298K~328K范围内,吸附等温线符合Freundlich吸附等温方程,主要为物理吸附。吸附过程中吸附晗变△H0,吸附自由能△G0,熵变△S0,表明天然海泡石对酸性蓝62的吸附反应是自发吸热、熵增过程。此外,根据实验数据计算吸附势E随吸附量的增加而减少。     

玉米秸秆活性炭的制备及其吸附含氮废水性能探析

采用玉米秸秆作为制备原料,KHCO₃为活化剂、HCl作为改性试剂制备改性玉米秸秆活性炭,吸附含氮废水,进行物理表征以及吸附动力学性能分析。本实验采取Freundlich与Langmuir模型对等温吸附曲线进行线性拟合,实验数据结果表明,玉米秸秆活性炭对氮素的吸附更加符合Freunglich方程,拟合相关性较好,R²=0.998。随后采用Lagergren准一级及准二级动力学速率模型对活性炭吸附氮素溶液动力学拟合,实验结果表明,Lagergren准二级速率模型可以最准确地描述吸附过程,其中R²=0.95。玉米秸秆活性炭对氨氮的最大吸附量常数达到407.51 mg·g^-1,表明吸附能力较强。     

交联淀粉微球对Ni~(2+)的吸附性能研究

以可溶性淀粉为原料,N,N'-亚甲基双丙烯酰胺为交联剂,采用反相悬浮聚合得到了一种交联淀粉微球(CSM利用扫描电镜、红外光谱仪和X射线衍射仪对其结构进行表征.研究了在不同温度下CSM对Ni2+的静态吸附行为,并根据吸附等温线研究了吸附热力学性质,结果表明:在308～328K和研究的浓度范围内,CSM对Ni2+吸附行为符合Freundlich方程;CSM吸附Ni2+的吸附焓变△H、吸附自由能变△G、吸附熵变△S均为负值,表明吸附是一个自发的、放热的熵减小过程,适当降低温度有利于吸附.热力学性质分析结果表明CSM主要通过物理吸附方式吸附Ni2+.     

D401大孔树脂吸附锰铁混合液中Fe~(3+)的热力学和动力学研究

采用D401树脂对锰铁混合液进行静态吸附性能及热力学、动力学研究,考察了Fe3+浓度、pH值和温度等对静态吸附Fe3+的影响,探讨吸附Fe3+的动力学过程,并采用Langmuir和Freundlich吸附模型对D401树脂吸附Fe3+的静态等温曲线进行了拟合。结果表明,在pH=1.5,温度313 K,Fe3+的最大静态吸附量是115.7 mg/g;D401对Fe3+吸附遵循Langmuir方程;△H Fe3+>0,ΔG Fe3+<0,表明D401对Fe3+的吸附是自发吸热过程;D401树脂对Fe3+的吸附符合拟二级动力学方程,颗粒扩散过程是吸附的控速步骤。静态吸附实验表明,D401大孔树脂能有效的对锰铁混合液中铁锰离子进行分离。     

CTMAB-磷石膏对Cr(Ⅵ)的吸附动力学研究

在微波环境下,制备了十六烷基三甲基溴化铵(CTMAB)修饰的CTMAB-磷石膏,并对其结构进行了表征。通过静态吸附实验,研究了CTMAB-磷石膏对Cr(Ⅵ)的吸附特性,探讨了吸附机理,结果表明:CTMAB-磷石膏对Cr(Ⅵ)的吸附符合Langmuir和Freundlich吸附等温模型,但Langmuir吸附等温模型能更好地描述吸附等温曲线。Lagergren准一级吸附动力学方程、Lagergren准二级吸附动力学方程、Elovich吸附方程以及粒子内扩散模型均可较好地描述吸附初始阶段,而整个吸附过程更好地符合Lagergren准二级吸附动力学方程,CTMAB-磷石膏对Cr(Ⅵ)的平衡吸附量为16.3225mg/g,吸附过程由物理吸附、化学吸附及络合沉淀作用共同控制。     

改性凹凸棒石对碱性蓝54的吸附试验研究

用静态吸附法研究了改性凹凸棒石对碱性蓝54的吸附特性,探讨了初始pH值、温度以及染料初始浓度等因素的影响。结果表明吸附动力学较好地符合Lagergren二级吸附速率方程。利用两种等温线方程对吸附过程进行拟合,显示不同温度下的吸附等温式都与Langmuir方程符合。热力学分析表明,吸附过程吸热,吸附焓变△H和熵变△S均为正值,吸附自由能变△G为负值。     

改型斜发沸石在Na+-Ca2+-Mg2+和NH4+-Ca2+-Mg2+水溶液体系中的离子交换平衡

研究了Na+-Ca2+-Mg2+与钠型斜发沸石和NH4+-Ca2+-Mg2+与铵型斜发沸石的离子交换平衡,分别测定出2个体系的离子交换平衡数据,并利用三维坐标绘制出三元离子交换平衡等温面,计算出改型沸石对体系中离子的分离因数. 结果表明,在Na+-Ca2+-Mg2+溶液体系中,Na+的分离因数>10,Ca2+的在0.4~10之间,Mg2+的小于0.4,斜发沸石离子交换顺序为Na+>Ca2+>Mg2+,且温度升高Ca2+和Mg2+的交换能力增强,而低温则有利于沸石对Na+的选择;在NH4+-Ca2+-Mg2+溶液体系中,NH4+的分离因数>15,Ca2+的在0.2~1.5之间,Mg2+的小于0.2,斜发沸石离子交换顺序为NH4+>Ca2+>Mg2+,且温度升高Ca2+和Mg2+的交换能力增强,NH4+的选择性降低.     

Electronic Structure and Properties of the O2+2, SO2+ and S2+2 Diatomic Dications

Multiply charged ions show novel energetic features which can potentially have useful photophysical properties. In order to investigate these interesting type systems, energy interaction curves for the ground and excited electronic states of O²⁺₂, SO²⁺, and S²⁺₂ have been generated by the ab initio complete active space multiconfiguration self-consistent field (CAS-MCSCF) method. The calculations were carried out in a triple-zeta sp plus double-zeta d Gaussian function basis set using compact effective potentials to replace the core electrons. In order to gauge the accuracy of the results, analogous calculations were carried out on the valence isoelectronic N₂ and NO⁺ systems for which experimental information is available for comparison of geometric and spectroscopic properties. Diverse high energy spectroscopy experiments on O²⁺₂ are interpreted and reconciled using the calculated ground and excited state energy interaction curves. Special attention is paid to the ₃Σ₊^u state, whose location and character have been particularly puzzling. Almost all the dication molecular states studied show the characteristic avoided crossing of diabatic states which gives a trapped equilibrium structure and a barrier to dissociation. These features make the dication kinetically stable, but thermodynamically unstable with an exothermic dissociation energy. The spectroscopy experiments on O²⁺₂ show that these states are experimentally attainable.     

十二烷基磺酸根插层Ni~(2+)-Fe~(3+)/Co~(2+)-Ni~(2+)-Fe~(3+) LDHs及其结构研究

应用水热技术制备了二元Ni2+-Fe3+-CO23- LDHs和三元Co2+-Ni2+-Fe3+-CO32- LDHs,以十二烷基磺酸根离子作为插层客体,通过离子交换反应在酸性溶液中实现了十二烷基磺酸根插层Ni2+-Fe3+ LDHs和Co2+-Ni2+-Fe3+-LDHs。十二烷基磺酸根在Ni2+-Fe3+LDHs层间出现了2种空间导向和排列:即十二烷基磺酸根以单层垂直方向排布和以双层垂直方向排布在层间;十二烷基磺酸根在三元组分Co2+-Ni2+-Fe3+-LDHs层间只有一种空间排列方式,即十二烷基磺酸根以单层垂直方向排布于Co2+-Ni2+-Fe3+-LDHs层间。     

粉煤灰及膨润土对Ni^2＋，Zn^2＋，Cd^2＋，Pb^2＋的吸附研究

研究了粉煤灰和膨润土对溶液中有毒重金属离子Ni~(2 )、Zn~(2 )、Pb~(2 )、Cd~(2 )的吸附能力。动态吸附试验显示,吸附过程是快速的。试验结果表明:粉煤灰对Zn~(2 )的吸附能力和膨润土相当,对Ni~(2 )、Cd~(2 )的吸附能力均大于膨润土。平衡吸附模型说明在高浓度下,Ni~(2 )、Zn~(2 )、Pd~(2 )在粉煤灰中,Ni~(2 )、Pd~(2 )在膨润土中的吸附符合Langmuir模式。试验还表明:随着吸附剂中Ni~(2 )、Zn~(2 )、Pb~(2 )、Cd含量增加,粉煤灰和膨润土对Ni~(2 )、Zn~(2 )、Pb~(2 )、Cd~(2 )的吸附百分率下降。     

高聚物萃取分离光度法测定Pb2+

利用非挥发性水溶性高聚物的水溶液在无机盐存在下可分成两相的特点,讨论了Pb2+、Cd2+、Co2+、Cu2+、Fe3+、Ni2+、Zn2+混合液中Pb2+的分离和测定条件,实现了Cd2+、Co2+、Cu2+、Fe3+、Ni2+、Zn2+与Pb2+的定量分离和测定,结果表明方法简便、可靠、快速,在Pb2+含量0～4.0μg/mL范围内有良好的线性关系.回收率在95%～105%.     

Adsorption behavior of kenyaite for Cu2+ and Pb2+

Journal of Porous Materials - Hydrated layered polysilicates (HLPSs) have received considerable attention as adsorbents because of their selective adsorption for heavy metal cations. However, the...     

Ionic migration and charge reduction in Ni2+-, Co2+- and Zn2+-exchanged Texas montmorillonite

Controlled calcination of ion-exchanged Texas montmorillonite leads to layer charge reduction. Detailed chemical analyses of both exchangeable and unexchangeable metal species lead to the conclusion that, in complete contrast to the situation with Wyoming bentonite, Ni²⁺, Co²⁺ and Zn²⁺ are all capable of migrating from the interlamellar space into the octahedral region of the sheets where they are (i) isomorphously exchanged for Mg²⁺, and to a proportionately smaller extent, for Fe²⁺, (ii) trapped in the octahedral vacancies. In addition, they are converted to unexchangeable species on the interlamellar sheet surfaces by high temperature hydrolysis leading to hydroxide or oxide formation. It is suggested that protons within the octahedral region are bound as -OH⁺ ₂rather than simply physically trapped.     

Adsorption of Zn2+ and Cu2+ onto sulphate and phosphate-modified bentonite

The modification of bentonite with sulphate and phosphate increased the cation exchange capacity (CEC) and adsorption of Cu²⁺ and Zn²⁺ but decreased the specific surface area (SSA). Phosphate modified bentonite had the highest adsorption capacity for both metal ions. The Fourier transformed infrared spectra indicated the bonding of sulphate and phosphate bentonite with sulphate and phosphate by the hypochromic and hyperchromic shifts are typical of physisorption and chemisorption mechanisms. Phosphate and sulphate were adsorbed through inner-sphere and outer-sphere complex formation. The isotherms were better fitted by the Langmuir model than the Freundlich model.     

Vapor-liquid equilibra for cyclohexane+2-propoxyethanol and cyclohexane+2-butoxyethanol systems

2-propoxyethanol (C₃E₁) and 2-butoxyethanol (C₄E₁) are nonionic surfactants which are a particularly interesting class of substances due to both inter-molecular and intra-molecular association, related to the presence of O and OH in the same molecule. Binary (vapor+liquid) equilibrium data were measured for cyclohexane+2-propoxyethanol and cyclohexane+2-butoxy ethanol systems at temperatures ranging from 303.15 K to 323.15 K at 10 K intervals. A static apparatus was used in this study. Two systems show positive deviation from Raoult’s law and no azeotrope. The experimental data were correlated well with Peng-Robinson-Stryjek-Vera equation of state using Wong-Sandler mixing rule incorporating the non-random-two-liquid model.     

二乙烯三胺基木质素吸附Cu2+、Ni2+的性能研究

以木质素与二乙烯三胺原料,通过环氧氯丙烷交联,制得一种新型金属离子吸附剂二乙烯三胺基木质素,通过吸附实验考察了pH、吸附时间及重金属离子浓度对其吸附Cu2+、Ni2+的影响。在pH=5,温度25℃的条件下,二乙烯三胺基木质素对Cu2+、Ni2+的饱和吸附量为44.84mg/g、34.13 mg/g,吸附符合二级动力学吸附方程,吸附过程比较符合Langmuir型等温吸附曲线。