接枝亲水型高分子的丝瓜络对水中重金属离子的吸附行为

采用接枝聚合的方法将亲水性聚丙烯酰胺接枝到丝瓜络上,部分水解的聚丙烯酰胺的接枝率可高达161.3%.选择典型的Cu~(2+)和Pb~(2+)体系,研究亲水型丝瓜络对水中重金属离子的吸附行为.结果表明,在单离子体系中,准二级动力学方程适于描述亲水型丝瓜络吸附动力学过程,饱和吸附量随着接枝率和pH值增加而增大,对Cu~(2+)和Pb~(2+)的最大饱和吸附量分别为647和887 mg/g.Langmuir和Freundlich等温吸附模型都适合描述等温吸附过程.8次吸附-解吸附循环实验表明,饱和吸附量基本保持恒定,同时对吸附机理进行了讨论.     

吡啶酮改性纤维素吸附剂对金属离子的吸附性能

经过两步简单反应合成了一种新型吡啶酮功能化纤维素吸附剂。该吸附剂的结构和表面形貌分别通过红外光谱和扫描电镜进行了表征,研究了其作为吸附剂对重金属离子的吸附性能。结果表明,吡啶酮双酸改性后纤维素吸附剂的表面变粗糙、比表面积增大,该吸附剂对Cu~(2+)、Pb~(2+)、Cd~(2+)、Co~(2+)的最大吸附容量分别达到146.52mg/g、233.05mg/g、192.08mg/g、258.13mg/g;对金属离子的吸附行为符合拟二阶动力学模型和Langmuir等温吸附模型;通过对吸附剂吸附金属离子前后的红外光谱研究,发现吡啶酮的酮羰基和羧酸基团同时参与了金属离子的吸附过程。     

纤维素基磁性聚氨肟树脂的研究

用醋酸纤维素包埋γ-Fe_2O_3作磁芯,经过接枝改性,首次合成了纤维素基聚氨肟树脂(MPAO)。实验结果表明,树脂有效地吸附Hg~(2-)、Cu~(2-)、Pb~(2+)、Ni~(2-)等重金属离子,优点是吸附速度快、易洗脱。吸附动力学证明化学反应是吸附速度的决定因素,与树脂吸附层的非交联结构有关。     

复合改性膨润土对2,4,6-三氯苯酚和Pb~(2+)的吸附行为研究

本文主要以钠基膨润土为原料,用十六烷基二甲基苄基氯化铵和乙二胺四乙酸二钠盐对膨润土进行复合改性,制得改性膨润土,用XRD对其结构进行表征,研究了改性后的膨润土对2,4,6-三氯苯酚和Pb~(2+)的吸附行为,结果表明,改性后的膨润土对2,4,6-三氯苯酚和Pb~(2+)的吸附性能明显提高,吸附等温线较好地符合Langmuir模型,改性膨润土对2,4,6-三氯苯酚和Pb~(2+)的最大吸附量分别为238.1mg/g和191.20mg/g,吸附动力学符合准二级反应动力学方程,其二级反应速率常数为分别为8.34×10~(-5)g/mgámin和5.62×110~(-5)g/mgámin,改性膨润土对2,4,6-三氯苯酚的吸附为吸热反应,而对Pb~(2+)的吸附为放热反应。     

淀粉接枝改性聚丙烯酸/钠高吸水性树脂吸附Pb2+的研究

以可溶性淀粉和丙烯酸为原料,过硫酸铵为引发剂,N,N-亚甲基双丙烯酰胺为交联剂,通过自由基聚合法制备可溶性淀粉接枝聚丙烯酸/钠高吸水性树脂,研究树脂对Pb~(2+)的吸附性。结果表明,接枝后树脂网络孔径增大,其吸附Pb~(2+)的pH值范围宽,饱和吸附时间短,最大吸附容量为277.7mg/g。吸附过程研究发现,淀粉接枝聚丙烯酸/钠高吸水性树脂对Pb~(2+)的吸附符合准二阶动力学模型,吸附的控速步骤为化学吸附;Langmuir等温吸附方程与实验数据吻合良好,表明对Pb~(2+)的吸附为均匀的单分子层吸附;吸附热力学表明,对Pb~(2+)的吸附为自发进行的放热反应。机理研究表明,吸附过程有树脂与Pb~(2+)的静电作用、羧酸根离子与Pb~(2+)二齿螯合配位作用以及Na+与Pb~(2+)的离子交换等,离子交换程度随着Pb~(2+)浓度的增加而增大。     

希夫碱型木质素基吸附材料的制备及其对Pb~(2+)吸附性能研究

以乙酸木质素为原料,通过曼尼希胺化反应和希夫碱反应制备希夫碱型木质素基离子吸附材料(SLA),利用红外光谱、核磁共振氢谱和元素分析等手段对SLA的结构进行表征。考察了溶液pH值、吸附剂用量和离子溶液初始浓度等因素对SLA吸附性能的影响。结果表明,在pH=5.0、吸附剂用量2.0g/L、Pb~(2+)溶液浓度200mg/L条件下,SLA对Pb~(2+)具有较高的吸附量(65.45mg/g)和良好的吸附选择性。研究结果表明,SLA对Pb~(2+)的等温吸附过程符合Freundlich等温吸附模型,存在非均匀多层吸附现象;SLA对Pb~(2+)的吸附动力学过程符合准二级吸附动力学模型,表明SLA对Pb~(2+)的吸附作用主要为化学吸附。     

MSCB吸附剂去除水体中Ni~(2+)、Cu~(2+)、Cr(Ⅵ)的机制研究

以NaOH和二硫化碳对甘蔗渣进行了改性,通过傅里叶变换红外光谱(FT-IR)、扫描电镜(SEM)对改性蔗髓纤维(MSCB)进行表征并研究了MSCB去除水中Cr(Ⅵ)、Ni~(2+)、Cu~(2+)的性能。结果表明,MSCB吸附重金属离子的平衡时间为30~60 min,处理含Cr(Ⅵ)浓度在10~40 mg/L范围内的废水去除率达97%以上,比改性前蔗髓纤维(SCB)对Cr(Ⅵ)的吸附率(23.7%)提高了74.35%。对含Ni~(2+)浓度30~60 mg/L的废水去除率达98%以上,吸附容量达59.12 mg/g、对Cu~(2+)浓度在20~55 mg/L废水的去除率在90%以上,吸附容量达49.9 mg/g。对电镀废水中Cr(Ⅵ)处理率达96.69%,吸附量8.16mg/g,出水浓度0.93 mg/L;Ni~(2+)去除率达99.13%,吸附量51.89 mg/g,出水浓度1.06 mg/L,水质澄清。     

Cu~(2+)负载疏松多孔型羟胺改性聚丙烯腈对As(V)的吸附性能

采用高内相比乳液模板法合成出疏松多孔型聚丙烯腈(PAN),对其进行羟胺改性后再与Cu~(2+)配位,得到Cu~(2+)负载疏松多孔型羟胺改性聚丙烯腈(AO-PAN/Cu~(2+))。对所合成的AO-PAN/Cu~(2+)吸附剂进行了红外光谱、扫描电镜、热重分析等表征,并研究了其对As(V)的吸附性能。该吸附剂对As(V)的最大吸附量为0.22mg/g,吸附过程符合拟二级动力学方程。在竞争离子存在下,AO-PAN/Cu~(2+)对As(V)具有较高的吸附选择性。固定床实验结果表明,AO-PAN/Cu~(2+)对含量为400μg/L的含砷模拟废水中的As(V)具有良好的分离性能,穿透体积达到110BV。     

Ca~(2+)交联聚丙烯酸钠的合成及其对Pb~(2+)的吸附研究

利用溶液聚合法和Ca~(2+)表面交联法制备了Ca~(2+)交联的聚丙烯酸钠(CPAANa)。在25℃条件下,以CPAANa为吸附剂,开展了对Pb~(2+)的吸附研究工作,以FT-IR,SEM和TGA测试手段分析了吸附前后CPAANa样品的变化。吸附研究显示,CPAANa在p H值为2~5.5的范围内具有很好的吸附性能,对初始浓度低于300mg/L的Pb~(2+)废水可以达到99%以上的去除率。CPAANa对Pb~(2+)的吸附动力学符合准二级动力学模型,其等温曲线符合Langmuir吸附模型,由此得到的最大吸附量为650.34mg/g。由D-R模型得出的平均吸附自由能E=26.1k J/mol,表明CPAANa对Pb~(2+)的吸附属于化学吸附。重复利用实验显示,该材料具有较好的重复利用性能。     

聚乙烯亚胺-磁性羧甲基纤维素复合物对铜离子和镉离子的吸附

制备了聚乙烯亚胺修饰的磁性羧甲基纤维素纳米复合材料(PEI-MCMC),对其结构进行了表征分析,探究了该材料在不同p H和时间、不同离子浓度下对铜离子(Cu~(2+))和镉离子(Cd~(2+))的吸附量。结果表明,PEI-CMC对Cu~(2+)和Cd~(2+)的吸附过程均符合拟二级动力学模型,为化学吸附的过程。该材料在pH 5～6条件下,Cu~(2+)和Cd~(2+)分别在10和25 min时达到吸附平衡,平衡时的理论吸附量分别为32.24和83.33 mg/g。该吸附材料对Cu~(2+)和Cd~(2+)的吸附速度快,适用条件广,便于分离,为含Cu、Cd的废液处理提供了一定的参考。     

离子强度对膨润土/木质素磺酸钠接枝丙烯酰胺-马来酸酐复合吸附树脂吸附Pb2+/Cu2+的影响

为揭示外加电解质离子强度对重金属离子吸附的影响规律与内在机制, 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(BLPAMA), 研究了外加电解质离子强度对BLPAMA吸附单一和二元Pb²⁺/Cu²⁺的影响规律, 以及有、无外加0.2 mol/L NaNO₃时BLPAMA对二元Pb²⁺/Cu²⁺的吸附等温线、吸附热力学及吸附动力学。 结果表明, 在单一Pb²⁺或Cu²⁺溶液中, 随离子强度增加, Pb²⁺和Cu²⁺吸附量降低;在二元Pb²⁺/Cu²⁺溶液中, 随离子强度增加, Pb²⁺吸附量降低而Cu²⁺吸附量提高。     

蒙脱土表面键合配位体固相萃取填料的制备及其对重金属离子的吸附性能

通过酸洗、硅烷偶联剂表面活化、键合苯甲酰异硫氰酸酯对蒙脱土进行改性,制得新型固相萃取(SPE)材料。 采用红外光谱、扫描电子显微镜、X射线光电子能谱表征了改性蒙脱土的结构和形貌。 考察了制备的SPE填料对水中As³⁺、Bi³⁺、Cu²⁺、Sb³⁺、Sn²⁺和Pb²⁺的吸附性能,确定了最佳固相萃取条件,对6种金属离子吸附容量分别为10.83、11.92、12.67、10.43、10.01及10.54 mg/g。 通过SPE与电感耦合等离子体质谱联用测定了样品中As³⁺、Bi³⁺、Cu²⁺、Sb³⁺、Sn²⁺和Pb²⁺ 6种重金属离子的含量,检出限分别为0.024、0.013、0.075、0.037、0.011和0.064 μg/L。     

Adsorption Mechanism of Composite Whisker on Copper Ions and Lead Ions

A new kind of inorganic composite adsorbent based on chitin whiskers(CHW) and potassium tetratitanate whiskers(PTW) was synthesized via the thermal deposition to remove Cu²⁺ and Pb²⁺ from wastewater. CHW could be successfully coated on the surface of PTW when thermal treated 8 times. The adsorption process was better fitted with the Langmuir and Freundlich models. The adsorption process was more conformed to the Pseudo-second-order model. The results from XPS(X-ray photoelectron spectrum) further show that the adsorption mechanism between CHW-PTW and Cu²⁺, Pb²⁺ are both ion exchange and chemical adsorption. Thermodynamic parameters suggest that the adsorption processes are nonspontaneous. The adsorption of Cu²⁺ and Pb²⁺ is endothermic and exothermic, respectively.     

Adsorption of Heavy Metal Ions from Aqueous Solutions by Zeolite Based on Oil Shale Ash: Kinetic and Equilibrium Studies

Na-A zeolite was successfully synthesized via the alkaline fusion method with oil shale ash as the raw material. The adsorption capacity of it was tested by removing Cu²⁺, Ni²⁺, Pb²⁺ and Cd²⁺ from aqueous solutions. The results reveal the maximum adsorption capacity of adsorbent for Pb²⁺, Cu²⁺, Cd²⁺ and Ni²⁺ were 224.72, 156.74, 118.34 and 53.02 mg/g, respectively. The effects of contact time and pH value of solutions on the adsorption efficiency of the zeolite were evaluated. Besides, The equilibrium adsorption data and the batch kinetic data were correlated with Langmuir and Freundlich models and the pseudo-first-order and pseudo-second-order models separately. The results show that the Langmuir isotherm and the pseudo-second-order equation were more suitable for the adsorption of Na-A zeolite for the metal ions. In addition, Thermodynamic parameters of the adsorption(the Gibbs free energy, entropy, and enthalpy) were also evaluated and discussed. The results demonstrate that the adsorption process was spontaneous and endothermic under natural conditions and the synthesized zeolite was an effective adsorbent for the removal of metal ions from aqueous solution.     

Chelating Properties of Salicylhydroxamic Acid-functionalized Polystyrene Resins and Its Application to Efficient Removal of Heavy Metal Ions from Aqueous Solutions

Salicylhydroxamic acid(SHA) was covalently bound onto crosslinked polystyrene spheres(CPSs) via the Friedel-Crafts alkylation reaction between chloromethylated CPSs and SHA in the presence of SnCl4 as the Lewis acid catalyst. The resulted SHA-CPSs possessed very strong chelating ability for heavy metal ions. In particular, the saturated adsorption amount of SHA-CPSs for Cu²⁺ ions could reach as high as 34.2 mg/g at 318 K. The chelating capability of SHA-CPSs towards heavy metal ions was pH and temperature dependent. SHA-CPSs also showed selective metal coordination with the chelating capacity decreasing in the order of Cu²⁺>Zn²⁺>>Pb²⁺. The adsorption isotherms conformed well to the Langmuir model, and the adsorption process was found to be entropy-driven and endothermic. Besides, SHA-CPSs possessed the excellent reusability.     

A Novel Hollow Carbon@MnO2 Electrospun Nanofiber Adsorbent for Efficient Removal of Pb2+ in Wastewater

Lead ion(Pb²⁺) is one of the most hazardous heavy metal ions in aquatic environments. Carbon materials and manganese dio-xide(MnO₂) have been shown to be prospective adsorbents to cope with the lead pollution. In this study, a novel hollow carbon@MnO₂ composite nanofiber adsorbent was prepared by the combination of electrospinning and carbonization. The PAN nanofiber membrane is subjected to a pre-oxidation and carbonization process, and then the obtained carbon nanofibers react with KMnO₄ solution during the hydrothermal process to develop the hollow carbon@MnO₂ nanofibers. The hollow carbon@MnO₂ nanofibers displayed a higher adsorption capacity of Pb²⁺ than carbon and MnO₂/PDA/PAN nanofibers. The maximum adsorption capacity toward Pb²⁺ by hollow carbon@MnO₂ nanofibers was 460.83 mg/g. After 5 adsorption-desorption cycles, the carbon@MnO₂nanofibers had a good recyclability and the removal efficiency remained 81.47%. Moreover, the removal efficiency of the hollow composite nanofibers for Pb²⁺ from real wastewater could reach 94.37%. This work shows a strategy for synthetics of the hollow carbon@MnO₂ nanofibers, which exhibits a promising potential in actual wastewater treatment.     

磁性碳纳米管表面新型镉离子印迹聚合物制备及其对大米中的镉离子富集

以苯胺修饰的磁性碳纳米管为基质,Cd²⁺为模板,甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂,在碳纳米管表面制备出一种新型磁性Cd²⁺印迹聚合物(MWNTs/MIIPs)。 采用扫描电子显微镜和红外光谱等技术手段对其形态和化学结构等进行详细表征。 吸附试验结果表明,该磁性印迹材料对Cd²⁺离子具有良好的吸附能力,最大吸附量为16.96 mg/g;选择吸附试验结果表明,该磁性印迹材料对Cd²⁺/Cu²⁺、Cd²⁺/Ni²⁺、Cd²⁺/Pb²⁺和Cd²⁺/Cr³⁺的相对选择因子分别是2.03、2.35、2.16和2.13。 结合原子吸收光谱分析技术,该材料MWNTs/MIIPs可用于大米中的Cd²⁺快速分离富集检测。     

磁性碳纳米管表面多金属离子印迹聚合物制备及应用

以磁性碳纳米管为载体,Co~(2+)、Cu~(2+)及Cd~(2+)等多种金属离子为模板和多巴胺为功能单体,研制一种对多种重金属离子具有高选择性吸附性能的磁性离子印迹聚合物(MIIPs)。采用红外光谱仪、透射电子显微镜、扫描电子显微镜和振动样品磁强计等技术手段对MIIPs进行了表征。采用原子吸收光谱详细研究了MIIPs的吸附性能,结果表明,MIIPs不仅具有优异的磁性能,而且对Cu~(2+)、Co~(2+)及Cd~(2+)具有快速、高效的选择识别能力,最大吸附量分别为46.08、36.35和30.65 mg/g。结合磁固相萃取和原子吸收光谱,MIIPs成功用于淤泥中Cu~(2+)、Co~(2+)及Cd~(2+)的同时分离富集,富集因子分别为18.6、13.4以及10.9。     

Study on the Preparation of Mercaptoacetic Acid-modified Heterophylla Shell and Its Application in Separation and Enrichment of Pb2+ in Environmental Samples

To increase the adsorption capacity of the Corylus heterophylla Fisch(HS) for Pb²⁺, HS was chemically modified using NaOH aqueous solution and 95% ethanol and was labeled as SHS; then SHS was chemically modified using mercaptoacetic acid. The SHS modified with mercaptoacetic acid(MHS) was characterized using FTIR, SEM, and XPS. The results indicated that the -SH group was present on MHS, and after Pb²⁺ adsorption, the absorption value of the characteristic peak of the -SH group decreased. The adsorption and desorption properties of this functionalized material were investigated as well as the influences of parameters, such as pH value, type of desorption reagent, dosage, flow rate and maximum sample volume. The Pb²⁺ adsorption of MHS reached a maximum with pH>5. The experimental data of Pb²⁺ adsorption using MHS were fitted using the Langmuir isothermal adsorption model, and a maximum adsorption capacity of 61.54 mg/g was obtained. This was much higher than the adsorption capacity of SHS before modification with the thiol group. After adsorption, MHS was desorbed using a 0.2 mol/L HCl solution, and the percent of desorption was higher than 99%. MHS was used as a solid-phase extractant in the analysis and determination of Pb²⁺ content in food and water samples, and the enrichment times achieved 150-fold.     

AStudyontheInfluenceofCu￣2￣＋，Cd￣2￣＋andPb￣2￣＋onTripleHelixPoly（A：2I）

ＡＳｔｕｄｙｏｎｔｈｅＩｎｆｌｕｅｎｃｅｏｆＣｕ￣２￣＋,Ｃｄ￣２￣＋ａｎｄＰｂ￣２￣＋ｏｎＴｒｉｐｌｅＨｅｌｉｘＰｏｌｙ（Ａ：２Ｉ）￣＊ＨＵＡＥｒ－ｂｉｎｇａ￣ｂ￣,ＹＡＮＧＰｉｎ￣ｂ￣＊￣＊,ＬＩＱｉｎｇ－ｓｈａｎ￣ａ,ＹＡＮＧＢｉｎｇ－ｓｈｅｎ...