粉煤灰合成沸石对重金属铅与镍的吸附性能研究

利用粉煤灰合成的沸石吸附混合重金属Ni~(2+)与Pb~(2+),考察吸附剂量、初始p H、反应温度与反应时间对其竞争吸附效果的影响,探讨沸石吸附Ni~(2+)与Pb~(2+)的吸附动力学。结果表明:随着吸附剂量的逐渐增大,沸石对Ni~(2+)与Pb~(2+)的吸附去除率不断提高,而单位质量吸附剂对Ni~(2+)与Pb~(2+)的吸附容量不断下降。在整个吸附过程中两种离子竞争吸附去除顺序是PbNi。初始p H值对沸石吸附Ni~(2+)与Pb~(2+)去除效果影响显著。酸性环境中沸石对混合重金属中Pb~(2+)的吸附抑制了其对Ni~(2+)的吸附。随着反应温度的上升与反应时间的延长,沸石对Ni~(2+)与Pb~(2+)的吸附去除率不断提高。沸石对Pb~(2+)的吸附去除率在各个反应温度均高于其对Ni~(2+)的去除率。沸石对混合重金属Ni~(2+)与Pb~(2+)的吸附动力学均符合准二级动力学模型。     

蒙脱石和高岭石吸附水溶液中重金属离子的实验研究

综述了近几年研究人员以蒙脱石、高岭石和膨润土作为吸附材料,去除水溶液中的砷、镉、铬、铜、铅几种重金属离子。通过酸性活化改性,有机分子嫁接改性,纳米氧化物涂层和柱撑等手段,提高了粘土矿物的吸附性能,达到更好的吸附效果。结果表明有机改性更有利于蒙脱石等粘土矿物对于重金属离子的吸附,同时指出pH是影响吸附效果的关键因素。     

壳聚糖及其衍生物吸附电镀废水中重金属离子的研究进展

壳聚糖是一种来源广泛、无毒、易降解的天然高分子材料,其分子中的羟基和氨基等官能团能与重金属离子进行螯合吸附。介绍了近几年壳聚糖对电镀废水中Cu2+、Zn2+及Cd2+等离子的吸附处理,并综述了壳聚糖的几种不同形式的衍生物吸附电镀废水中重金属离子的研究进展。     

Studies on the mechanical,thermal, and morphological properties of poly(ether ether ketone)/poly(ether sulfone)/barium titanate nanocomposites: Correlation of experimental results with theoretical predictive models

In this study, mechanical, thermal, and morphological properties of the nanocomposites fabricated with the optimized blend of poly(ether ether ketone) (PEEK) and poly(ether sulfone) (PES) incorporated with nanobarium titanate (BT) were investigated. The optimized blend was based on the mechanical and thermal properties of the PEEK and PES in the ratio of 75 : 25 wt %. Nanoparticles were incorporated into the optimized blend with the help of twin‐screw extruder. The concentration of nano‐BT was varied from 2 to 6 wt % (0.41–1.28 vol %). With the increase in the nanosized BT concentrations, the tensile strength, tensile modulus, and elongation at break increased, whereas the crystallinity of the nanocomposites calculated by using differential scanning calorimetry method was found to decrease marginally. Morphological studies were carried out using scanning electron microscopy. The nanocomposites were evaluated by using theoretical predictive models according to “Pukanszky model” applicable to tensile strength and “Takayanagi's model” and “Guth and Smallwood model” applicable to tensile modulus. Upper and lower boundary of Hashin–Shtrikman model as well as Paul's model, applicable to tensile modulus, were also used to compare the experimental data. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Adsorption of Hg(II) Ions by 3-Mercaptopropyltriethoxysilane Modified Mesoporous Silica Based on Multiwalled Carbon Nanotubes: Equilibrium,Kinetic, and Thermodynamic Studies

In this study, 3-mercaptopropyltriethoxysilane (MPTS) modified mesoporous silica based on multiwalled carbon nanotubes (MWCNTs@mSiO₂-MPTS) was successfully prepared. The adsorption material was characterized and used for adsorbing Hg(II) ions from aqueous solution. The equilibrium data conformed better to the Langmuir isotherm with maximum adsorption capacity calculated 349.65 mg/g at 40ºC. The kinetics analysis revealed the adsorption process fitted well with the pseudo-second-order kinetic model. The thermodynamic parameters indicated the adsorption process was spontaneous and endothermic. All results obtained suggested that MWCNTs@mSiO₂-MPTS may be employed as an efficient material for the adsorption or preconcentration of Hg(II) ions from aqueous solution.