高性能木质素基重金属离子吸附凝胶的制备

以木质素磺酸钠(LS-Na)、丙烯酰胺(AM)、马来酸酐(MAH)为原料,膨润土(Bentonite)为无机添加剂,过硫酸钾(KPS)为引发剂,N,N-亚甲基双丙烯酰胺(NMBA)为交联剂,采用溶液接枝共聚合法制备了两种木质素基重金属离子吸附凝胶:膨润土/木质素磺酸钠接枝丙烯酰胺(BLPAM)、膨润土/木质素磺酸钠接枝丙烯酰胺马来酸酐(BLPAMA),研究了不同后处理方式对于两种凝胶吸附性能的影响。结果表明,BLPAM皂化产物具有很好的重金属离子吸附容量和去除率;BLPAMA皂化产物具有很高的Pb2+选择性。     

BLAMA复合吸附树脂制备与吸附性能

以木质素磺酸钠(LS-Na)、丙烯酰胺(AM)、马来酸酐(MAH)为原料,膨润土(Bentonite)为无机添加剂,过硫酸钾(KPS)为引发剂,N,N-亚甲基双丙烯酰胺(NMBA)为交联剂,通过溶液聚合法制备了膨润土/木质素磺酸钠接枝丙烯酰胺-马来酸酐复合吸附树脂(BLAMA)。以二元Pb2+/Cu2+溶液中对Pb2+的吸附量及其吸附选择性为参考指标,得到实验范围内的较优配方为m(LS-Na)∶m(Mtotal)=1∶7,m(AM)∶m(MAH)=1∶1,m(KPS)=0.7%,m(NMBA)=0.3%(KPS和NMBA的质量均相对于单体总质量Mtotal),pH值=4。此时所得树脂吸附性能较好,在二元Pb2+/Cu2+溶液中Pb2+最大吸附量为0.471mmol/g,Pb2+对Cu2+的吸附选择性摩尔比为3.6∶1。     

共存离子对Bentonite/LS-g-AM-co-MAH吸附Pb~(2+)的影响

采用自制膨润土/木质素磺酸钠接枝丙烯酰胺-马来酸酐复合吸附树脂(Bentonite/LS-g-AM-co-MAH),研究了外加电解质中竞争阳离子与共存阴离子对Bentonite/LS-g-AM-co-MAH吸附Pb~(2+)的影响。结果表明:竞争阳离子Li~+、Na~+、K~+、Mg~(2+)、Ca~(2+)、Ni ~(2+)、Co~(2+)、Zn~(2+)、Cd~(2+)和Cu~(2+)抑制Pb~(2+)的吸附,抑制作用顺序为Cu~(2+)Cd~(2+)Zn~(2+)Co~(2+)Ni ~(2+)Ca~(2+)Mg~(2+)K~+Na~+Li~+;Fe~(3+)和Al~(3+)在pH=2.0~3.0时抑制Pb~(2+)的吸附,在pH=4.0~6.0时促进Pb~(2+)的吸附,两者的影响顺序为Fe~(3+)Al~(3+)。共存阴离子NO_3~-、Cl~-和Br~-抑制Pb~(2+)的吸附,抑制作用顺序为Br~-Cl~-NO_3~-;SO_4~(2-)和PO_4~(3-)有利于去除Pb~(2+),两者影响基本相同。     

羽毛蛋白接枝丙烯酸-丙烯酰胺高吸水性树脂的吸附性能

通过水溶液聚合法合成了羽毛蛋白接枝丙烯酸-丙烯酰胺高吸水树脂,即FP-P(AA-AM)。研究了树脂在单一Cd2+溶液中的吸附行为以及在Cd2+、Cu2+、Zn2+三元混合溶液中的选择性吸附性能。结果表明,在单一Cd2+溶液中,FP-P(AA-AM)树脂对Cd2+的吸附容量随硫酸镉溶液浓度的增大而增大,最高可达2.4mmol/g。吸附Cd2+至饱和的树脂能在1mol/L的HCl溶液中很好的进行解吸附,3min时解吸附率即可达到83.3%。在较高浓度的三元金属离子混合溶液中,FP-P(AA-AM)树脂对3种离子呈现出一定的选择性吸附,其平衡吸附量顺序为:Cu2+Cd2+Zn2+。     

响应面法优化木质素基选择性吸附树脂的皂化条件

采用响应面法研究了膨润土/木质素磺酸钠接枝丙烯酰胺选择性吸附树脂(BLPAM)的皂化实验。以氢氧化钠溶液浓度、皂化温度、皂化时间为影响因素,以Pb~(2+)吸附量、Cu~(2+)吸附量、Pb~(2+)对Cu~(2+)的选择性吸附系数、Pb~(2+)去除率、Cu~(2+)去除率为响应值建立Box-Behnken数学模型,通过响应面分析得到针对各响应值的主次因素和优化皂化条件。采用组合赋权法确定各响应值的权重,获得最终的优化皂化条件。结果表明,BLPAM的优化皂化条件为:氢氧化钠溶液浓度1.45mol/L、皂化温度98℃、皂化时间2.90h,所得皂化BLPAM树脂在二元Pb~(2+)/Cu~(2+)溶液中对Pb~(2+)吸附量为1.772mmol/g,Cu~(2+)吸附量为1.719mmol/g,Pb~(2+)对Cu~(2+)的选择性吸附系数为1.604,Pb~(2+)去除率为96.062%,Cu~(2+)去除率为93.864%。     

木质素基树脂的制备及其对重金属离子的吸附性能

以木质素磺酸钠为原料,利用反相悬浮聚合技术,成功制备木质素基树脂.研究了木质素基树脂的制备工艺及其对重金属离子Pb2+、Cd2+的吸附性能.结果表明,优化的聚合条件为:液体石蜡与反应水溶液的相比为3:1、分散剂占有机相百分含量为2%、温度为90℃、盐酸浓度为3mol/L、甲醛占木质素磺酸钠百分含量为9%、聚合时间为2h.30℃时,所制备的树脂对Pb2+、Cd2+的饱和吸附量分别达到33.6523mg/g和30.12mg/g.所制备的木质素基树脂有大量羟基和磺酸基等含氧基团存在,非常有利于它对重金属离子的吸附.木质素基树脂的比表面积为0.0963m2/g,孔容为0.002389cm3/g,平均孔径为99.2208nm,表明该树脂具有大孔树脂的结构特点.     

铅离子显色印迹吸附剂的制备及其吸附性能

以Pb2+为模版分子,在硅胶表面接枝双硫腙,利用溶胶-凝胶法合成一种Pb2+显色印迹吸附剂(MIPs)。采用红外(IR)和扫描电镜(SEM)对MIPs进行了表征。通过平衡吸附实验,研究了MIPs的吸附性能、显色性能和其对Pb2+的选择识别性能。结果表明,双硫腙通过与硅胶形成氢键而接枝在硅胶表面;MIPs对Pb2+的显色限为10μmol/L;在Cd2+存在的条件下,其对Pb2+的相对选择系数为250;MIPs对Pb2+的吸附可以用Langmiur等温吸附方程来拟合,吸附焓变为66.054kJ/mol。制备的MIPs在5min内吸附率可以达到97%,可以用于含铅废水中Pb2+的分离和测定。     

蒙脱土/海藻酸钠接枝丙烯酸高吸水性复合物的制备及吸附性能研究

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+、Ni 2+的最大吸附量分别为968.9、231.0及236.0mg/g,其中对Pb2+和Cu2+的吸附符合Langmuir吸附模型,而对Ni 2+的吸附符合Freundlich吸附模型。     

聚（丙烯酰胺-丙烯酸钠）复合膨润土制备及其对Pb2+的吸附

由溶液聚合法制备了聚(丙烯酰胺-丙烯酸钠)复合膨润土吸附剂,通过FT-IR、XRD、TG-DTG、比表面积和SEM对复合物结构进行了表征。结果表明,丙烯酰胺和丙烯酸钠与膨润土发生插层聚合反应,形成了致密和热稳定性较好的层状复合物。聚(丙烯酰胺-丙烯酸钠)复合膨润土具有—COO-基团与膨润土层间阳离子及Si—OH、Al—OH基团的络合作用要强于聚丙烯酰胺复合膨润土,易于络合溶液中的阳离子。聚丙烯酰胺-丙烯酸钠复合膨润土通过离子交换和络合吸附Pb2+,吸附过程符合Langmuir等温吸附模型和二级动力学吸附模型,平衡吸附量为112.74mg/g。     

PAMPS高吸水性树脂吸附性能

用溶液聚合法合成了聚(2-丙烯酰胺-2-甲基丙磺酸)高吸水性树脂(PAMPS树脂),研究了树脂在Pb(NO3)2、Cu(NO3)2、Zn(NO3)2溶液中的吸附性能,结果表明,在单一金属离子溶液中,实验范围内PAMPS树脂吸附量随溶液浓度增加而增大,对Pb2 的吸附量还随交联剂浓度和单体中和度增加而增大;在二元和三元混合金属离子溶液中,PAMPS树脂对Pb2 有很好的选择吸附性。     

One pot synthesis of monodispersed L-glutathione stabilized gold nanoparticles for the detection of Pb2+ ions

Direct mixture of Au³⁺ with glutathione (GSH), which act as both reduction agents and stabilizers, in aqueous solution gave rise to production of gold nanoparticles (Au NPs) with uniform sizes of around 21 nm. The GSH stabilizer Au NPs in solution show immediate aggregation after addition of 1 mol/L NaCl aqueous solution containing Pb²⁺ ions. The Pb²⁺-induced aggregation in Au NP solution is monitored by both colorimetric response and UV-vis spectroscopy. A rather broad linear range (from 0.1 to 30 μmol/L) and low detection limit (0.1 μmol/L) are explored for Au NP sensors used for detection of Pb²⁺ ions. Furthermore, the response of GSH-stabilized Au NPs toward Pb²⁺ ions is specific compared with other possible interferants (Hg²⁺, Mg²⁺, Zn²⁺, Ni²⁺, Cu²⁺, Co²⁺, Ca²⁺, Mn²⁺, Cd²⁺, and Ba²⁺).     

一种新型膦酸锆孔材料的合成及其对金属离子的吸附性质

骨架含强配位基的有机无机杂化多级孔材料合成是目前吸附研究的一个重要领域。以bis (hexamethylene) triamino-N, N-bisacetyl-phosphonic acid和ZrOCl₂·8H₂O为原料、应用水热合成技术合成了一种新型膦酸锆多级孔材料ZrPTA, 并通过FT-IR、TGA、XRD、XPS、SEM以及元素分析等手段对制备产物进行了表征。研究结果表明, ZrPTA具有棒状微形貌, 其内部存在大量直径为1.38 nm和1.93 nm的微孔以及直径为2.99 nm的介孔, 其表面积为112.2 m²/g。ZrPTA对水溶液中Pb²⁺、Cu²⁺和Cd²⁺三种金属离子具有良好的吸附作用, 最大吸附量分别为742.7、689.8和627.0 mg/g, 远远高于文献报道值。这一性质使ZrPTA具有潜在的废水处理功效, 显示出诱人的应用前景。     

新型配体(MRBHP)分子的制备与MRBHP-Al3+光学性能与应用研究

以罗丹明B酰肼为主体,利用马来酸酐、4-氨基苯甲醛为原料修饰主体设计合成一种功能性发光小分子配体(MRBHP)。MRBHP在乙腈与水溶液(v/v=95∶5)中与Al³⁺结合形成配合物后,溶液颜色由无色变为红色。通过核磁共振、红外光谱、紫外可见吸收光谱对配体结构以及MRBHP与Al³⁺的配位方式与性能进行了表征。结果表明,Al³⁺与MRBHP亚氨基的N原子,羰基的O原子以及马来酸酐的O原子结合以1∶1的方式形成配合物,配合物呈现特异性强光学吸收,吸收峰波长为558 nm。同时应用研究发现,这种配体对Al³⁺呈现很强的选择性,在558 nm峰位置的吸收且有较强的抗干扰能力;同时配体对Al³⁺线性检测范围为0.2~1μM时,最低检测限为0.14μM,配位常数为1.61×10^-6M^-1。     

印迹改性磁性交联壳聚糖的表征及吸附性能

为了提高壳聚糖（CS）对Pb²⁺的去除能力,制备了印迹改性磁性交联壳聚糖（Pb-TMCS）,采用FTIR、SEM和XRD对其结构和形态进行了表征,研究了Pb-TMCS对Pb²⁺的吸附、脱附性能及选择性。结果表明：与CS相比,Pb-TMCS的表面孔隙和褶皱增多;Pb-TMCS引入了更多的-OH和-NH₂;Pb-TMCS内部包覆磁性物质Fe₃O₄,Pb-TMCS对 CS的相对选择性系数大于2;Pb-TMCS对Pb²⁺的吸附量从CS的25.57 mg/g提高到45.26 mg/g,脱附3次后仍可重复使用。Pb-TMCS回收方便,对Pb²⁺选择吸附性能好,无污染,在重金属废水处理中具有广阔的应用前景。     

Lead (II) ion selective electrodes based ondiphenylmethyl-N-phenylhydroxamic acid ionophore in cyanocopolymermatrix

A Pb²⁺ ion selective electrode has been prepared using diphenylmethyl-N-phenylhydroxamic acid (DPNINPRA) as ionophore and cyanocopolymer as new membrane matrix. The electrode (Membrane-2) exhibited a Nernstian slope of 36.75±0.001 mV decade^-1 activity of Pb²⁺ ions on varying the Pb²⁺ ions activity from 7.41×10^-8 to 3.68×10^-1 mol dm^-3. The electrode has exhibited a response time of 13.0±s at 1.0×10^-3 mol dm^-3 activity of Pb²⁺ ions and also revealed an improved selectivity in presence of various interfering ions. The high dipolar property of the selected cyanocopolymer has reduced significantly the anions interference and shown potential response independent to the activity of sodium tetraphenylborate (NaTPB). The electrode has shown isothermal point of 30°C as determined from a hysteresis curve. Sensitivity of the electrode has shown a significant variation with thickness of the membrane. The electrode has shown a constant response on continuous use for a period of six months without any drift in potential and has been also found to be useful as indicator electrode for potentiometric titration of Pb²⁺ ions     

Synthesis of β-cyclodextrin functionalized gold nanoparticles for the selective detection of Pb2+ ions from aqueous solution

In the present study we carried out the synthesis of β-cyclodextrin (β-CD) functionalized gold nanoparticles (AuNPs) using a microwave assisted heating method in alkaline media. Stable dispersion of β-CD stabilized AuNPs was obtained at an optimized pH of 10.5. At this pH value the deprotonated secondary hydroxyl group of β-CD shows the highest chelating affinity toward Pb²⁺ ions thereby inducing AuNP aggregation. The Pb²⁺ induced aggregation in β-CD-AuNP solution is monitored by both colorimetric response and UV-Vis spectroscopy. TEM, DLS and FTIR analyses were carried out to confirm the Pb²⁺ ion induced aggregation behaviour of β-CD-AuNPs under alkaline conditions. Furthermore at the experimental pH the response of the β-CD-AuNP system towards Pb²⁺ ions is selective when compared with other interfering metal cations.     

聚天冬氨酸/木质纤维素水凝胶的制备及吸附性能

采用水溶液聚合法合成聚天冬氨酸（PASP）/木质纤维素（LNC）水凝胶;考察了预处理时间、预处理温度、KMnO₄浓度、戊二醛用量、PASP的用量、反应时间以及反应温度对PASP/LNC水凝胶吸附Pb2+、Cd2+性能的影响;运用Langmuir吸附等温线计算PASP/LNC水凝胶最大吸附量;使用HNO₃对PASP/LNC水凝胶进行脱附再生实验;采用SEM和FTIR对水凝胶的结构进行表征。吸附结果表明:预处理时间15 min,预处理温度50 ℃、KMnO₄浓度0.06 mol·L-1、戊二醛用量1.00 g、PASP用量11 g、反应时间3.5 h且反应温度70 ℃时,对Pb2+、Cd2+的平衡吸附容量分别为980.39 mg·g-1、813.01 mg·g-1。 吸附/脱附循环实验表明:循环吸附脱附4次后PASP/LNC水凝胶吸附量仍较高,PASP/LNC水凝胶是一种可循环利用的吸附剂。表征结果表明:PASP/LNC水凝胶的表面有大小不等的孔隙,PASP的—COOH与LNC的O—H发生缩聚反应,形成具有三维网络结构的水凝胶。      

Chemical synthesis of nanocrystalline lead zirconate-titanate powders using tartarate precursor

Nanocrystalline (30 nm) lead zirconate-titanate (PZT) ceramics, with Zr/Ti ratio 60:40, was prepared by a chemical method starting from a mixed metal ion–tartarate (Zr⁴⁺, Ti⁴⁺)–EDTA (Pb²⁺) complex solution. After complete evaporation of the mixed complex solution, a fluffy dried mass, known as precursor material was obtained. Heat-treatments of the precursor material at 400°C/2 h resulting single phase PZT. The precursor and heat-treated powders were characterized by TG/DTA, XRD and TEM analysis. The result shows that the process provides a technically simple route for the preparation of nanocrystalline PZT powders at low preparation temperatures.     

Application of Multi-walled Carbon Nanotubes/Nafion Composite Film in Electrochemical Determination of Pb2+

In this work, insoluble multi-walled carbon nanotubes (MWNTs) was dispersed into ethanol in the presence of 1% Nafion, resulting in a stable and well-distributed MWNTs/Nafion suspension characterized by TEM and particle size analyzer. After evaporation of ethanol, a uniform MWNTs/Nafion composite film-coated glassy carbon electrode (GCE) was prepared and then characterized with SEM. Furthermore, the electrochemical behavior of Pb²⁺ at the unmodified GCE, Nafion film-modified GCE and MWNTs/Nafion film-modified GCE was investigated. It was found that the reduction peak potential shifts positively and peak current remarkably increases at the MWNTs/Nafion film-modified GCE, suggesting that MWMTs/Nafion film-modified GCE exhibits catalytic ability to electrochemical reduction of Pb²⁺. Based on this, a sensitive and convenient electrochemical method was proposed for the determination of Pb²⁺. Finally, the MWMTs/Nafion film-modified GCE was successfully used to detect Pb²⁺ in a water sample.