钠基膨润土对废水中Ni2+,Cu2+的吸附效果

为了提高膨润土吸附废水中Ni2+,Cu2+的效果,对其改性制备了钠基膨润土,考察了吸附时间、废水pH值以及Ni2+和Cu2+初始浓度对自制钠基膨润土吸附Ni2+,Cu2+效果的影响,分析了吸附等温线,并探讨了吸附机理。结果表明:钠基膨润土对Ni2+,Cu2+都有较好的吸附性能;初始阶段(前10 min)吸附很快,之后随时间延长吸附量提高甚微;pH值为6.2时,处理后的水质即可达国家排放标准;随着Ni2+,Cu2+初始浓度增加,去除率先增加后降低,而吸附量迅速增加,Ni2+和Cu2+初始浓度分别为25 mg/L和40 mg/L时,钠基膨润土对Ni2+,Cu2+的去除率均可达98.6%;钠基膨润土对Ni2+,Cu2+的吸附等温线符合Freundlich吸附等温式。     

弱酸型酚醛树脂对重金属离子的吸附

研究了以苯酚、氯乙酸及甲醛等为原料合成的弱酸型酚醛树脂对重金属离子Ni2+,Cu2+,Zn2+,Pb2+的吸附性能,考察了吸附时间、吸附温度、溶液浓度及pH值对该树脂吸附性能的影响。结果表明,在温度为25℃、pH值为4.5的条件下,该树脂对Ni2+,Cu2+,Zn2+,Pb2+的吸附容量可达到2.4×10-3mol/g,去除率均可达到97.5%以上。吸附了重金属离子的树脂可用5%的盐酸再生并回收重金属离子。     

胶原/纤维素/壳聚糖凝胶珠对水溶液中Ni~(2+)的吸附

在以离子液体1-丁基-3-甲基咪唑氯盐([C4mim]Cl)为溶剂,制备胶原和纤维素复合凝胶珠吸附剂过程中,加入少量壳聚糖对凝胶珠进行改性。吸附实验结果显示,胶原/纤维素/壳聚糖凝胶珠(CCHB-CS,质量比2/3/1)能有效吸附水溶液中的Ni 2+,相较于胶原/纤维素凝胶珠(CCHB,质量比1/1)和壳聚糖/纤维素凝胶珠(CCSHB,质量比1/1),CCHBCS对Ni 2+离子的吸附能力有所降低;溶液pH值会影响CCHB-CS对Ni 2+的吸附,pH7.0为最佳条件;Langmuir单分子吸附模型适用于描述CCHB-CS吸附行为。     

聚丙烯腈纤维改性条件优化及其对模拟电镀废水的净化作用

为了寻求低价、环保的电镀废水处理方案,将廉价的聚丙烯腈(PAN)纤维与羟胺试剂反应对PAN纤维进行改性,使其上氰基螯合获得偕胺肟基纤维。通过改变各种改性条件,探讨了改性条件对PAN改性纤维在重金属单离子溶液和多离子混合溶液中吸附性能的影响。结果表明:最佳改性条件为21.2 g/L PAN纤维,27.0 g/L盐酸羟胺,pH值为7.0,70℃下反应2 h;改性PAN纤维对模拟电镀废水中的Cu2+,Zn2+,Ni2+,Pb2+,Cd2+等重金属离子均有较好吸附性能,其中对Cd2+吸附效果最好,吸附量为55 mg/g;在多离子混合溶液中优先选择吸附Cd2+;改性PAN纤维再生效果优良,可重复利用。     

腐植酸树脂对电镀废水中重金属离子的吸附

利用泥炭为原料制备出腐植酸树脂。在动态条件下 ,研究了腐植酸树脂对重金属离子Pb2 +、Cu2 +、Zn2 +、Ni2 +、Cr3+的吸附效果及条件。同时探讨了腐植酸树脂对Pb2 +、Cu2 +、Zn2 +、Ni2 +、Cr3+的吸附与解吸再生机理。含Pb2 +、Cu2 +、Zn2 +、Ni2 +、Cr3+的电镀废水经腐植酸树脂吸附后 ,废水中重金属离子的含量低于国家排放标准     

N-羧甲基壳聚糖的合成改进及吸附性能

采用氯乙酸替代乙醛酸与壳聚糖反应,以Na2CO3为缚酸剂,合成了N-羧甲基壳聚糖,并采用红外光谱(FT-IR)、核磁共振(1H-NMR和13C-NMR)对其进行表征。考察了N-羧甲基壳聚糖对Ni2+的吸附性能,探讨了N-羧甲基壳聚糖的取代度、溶液初始pH值和吸附时间等因素对吸附量的影响。研究发现,羧甲基化发生在壳聚糖的氨基上。当产品的取代度为1.24时,最佳初始pH值为7,最佳吸附时间为2h,其吸附量为124.5mg/g。FT-IR表征说明羧基和Ni2+发生了配位反应。     

Cu~(2+)-IIP印迹材料的制备及性能研究

以Cu2+为模板,环氧氯丙烷(ECH)为交联剂,羧基碳纳米管(MWNTs-COOH)为载体,采用"Grafting onto"方法在羧基碳纳米管表面键连大分子链聚乙烯亚胺(PEI),制备了功能单体MWNTs-CO/PEI,获得铜离子印迹材料。利用FTIR、TEM对产物进行了表征,探讨了模板离子的初始浓度、溶液pH值、吸附时间对吸附容量的影响,以及印迹材料的吸附选择性和重复使用率。结果表明,PEI中的N-H键断裂,H原子被烷基取代,环氧氯丙烷发生开环反应,键连到PEI的N原子上;羧基碳纳米管表面包覆了一层厚度约为20nm的印迹层,呈蜂窝状;在Cu2+初始质量浓度为100mg/L、pH=6、吸附时间为1h时,Cu2+-IIP印迹材料和非印迹材料的最大吸附容量分别为43.68mg/g和21.85mg/g;在同时存在Cu2+、Zn2+的溶液中,印迹材料的选择性能较好;重复使用时,吸附性能稳定。     

羧酸盐/玉米芯接枝共聚物的制备及其对Cd2+和Ni2+的吸附

利用原子转移自由基聚合技术在玉米芯表面引发丙烯酸甲酯发生聚合反应,再分别通过NaOH和t-BuOK进行水解,制备出两种羧酸盐/玉米芯接枝共聚物(MC-g-PAA-Na和MC-g-PAA-K).结果 表明:两种羧酸盐/玉米芯接枝共聚物吸附Cd2+和Ni2+是自发、吸热且伴随焓增加的过程,该过程更符合Langmuir模型,...     

层状金属有机框架材料用于水溶液中137Cs的高效去除

¹³⁷Cs主要来源于核武器试验和核电站产生的放射性废物, 具有高溶解度和高迁移率的特点, 因此从放射性废液中有效去除 ¹³⁷Cs是一项长期的挑战。本研究通过溶剂热法合成了一种二维层状阴离子骨架材料SZ-6, 并对其吸附性能进行了系统的研究。利用单晶衍射仪、X射线衍射仪和扫描电子显微镜等对SZ-6的结构、形貌和稳定性进行了表征与测试。采用批实验研究了水溶液中Cs ⁺的吸附行为。结果表明: 在浓度为10 mg/L的Cs ⁺溶液中, SZ-6的吸附动力学可在5 min内达到平衡, 是目前去除Cs ⁺最快的吸附剂材料之一; SZ-6在pH4~12范围内表现出良好的去除能力; 在过量Na ⁺、K ⁺、Ca ²⁺竞争阳离子存在的情况下仍具有较好的选择性。     

污泥制备活性炭对 Pb(Ⅱ)和Ni(Ⅱ)的吸附和回收利用

在静态条件下研究了用污泥制备的活性炭吸附剂去除水溶液中Pb(Ⅱ)、Ni(Ⅱ)的效果,考察了溶液pH值、吸附时间、吸附剂用量和Pb(Ⅱ)、Ni(Ⅱ)的初始浓度对去除率的影响.结果表明,污泥制备的活性炭吸附剂对Pb(Ⅱ)、Ni(Ⅱ)具有较强的吸附性能,pH值是影响吸附的主要因素;吸附过程符合Langmuir吸附等温式;在试验条件下,其对Pb(Ⅱ)具有更高的去除能力.还探讨了吸附Pb(Ⅱ)、Ni(Ⅱ)后回收铅和镍的可行性.     

Heavy metal precipitation by polycation-polyanion complex of PEI and its phosphonomethylated derivative

The removal of various heavy metal ions such as Cu2+, Co2+, Zn2+, Ni2+ and Pb2+ from aqueous solutions by precipitation with polyelectrolyte complex of PPEI and PEI was conducted. Heavy metal binding with PPEI was initially allowed to occur and then upon equilibration, PEI was added to initiate precipitation of the polyelectrolyte complex together with the heavy metal ion. The PPEI-PEI system was found effective for heavy metal scavenging purposes even in the presence of high concentrations of non-transition metal ions like Na+. Heavy metal concentration may be reduced beyond emission standards for industrial wastewaters. The PPEI-PEI polyelectrolyte complex was found to be more effective than traditional precipitation methods for the treatment of a representative electroless Ni plating waste solution.     

PAAS高吸水树脂对重金属离子盐溶液的吸液及吸附性能

用聚丙烯酸高吸水树脂(PAAS)研究了单一和混合重金属离子硝酸盐溶液中的吸液和吸附性能.在Pb2 、Ni2 、Cd2 、Zn2 、Mn2 和Cu2 的一、二元溶液中,PAAS的吸液倍率随时间延长而增加,约50min达吸液平衡,一元金属离子溶液中平衡吸液倍率为160～190g/g,而对Cr3 溶液,最大为120g/g;二元金属离子混合溶液中平衡吸液倍率都在150～180g/g之间,有Cr3 存在时平衡吸液倍率最小.对上述单一金属离子的吸附量随时间延长而增加,约180min达吸附平衡,平衡吸附量顺序为:Pb2 ＞Cd2 ＞Ni2 ＞Cu2 ＞Zn2 ＞Mn2 ＞Cr3 .对二元混合金属离子溶液,吸附量随时间增加而增加,30min后逐渐变慢,约70min后达吸附平衡.     

Adsorption of copper (II), chromium (III), nickel (II) and lead (II) ions from aqueous solutions by meranti sawdust

The present study proposed the use of meranti sawdust in the removal of Cu(II), Cr(III), Ni(II) and Pb(II) ions from synthetic aqueous solutions. Batch adsorption studies showed that meranti sawdust was able to adsorb Cu(II), Cr(III), Ni(II) and Pb(II) ions from aqueous solutions in the concentration range 1–200 mg/L. The adsorption was favoured with maximum adsorption at pH 6, whereas the adsorption starts at pH 1 for all metal ions. The effects of contact time, initial concentration of metal ions, adsorbent dosage and temperature have been reported. The applicability of Langmuir, Freundlich, and Dubinin–Radushkevich (D–R) isotherm was tried for the system to completely understand the adsorption isotherm processes. The adsorption kinetics tested with pseudo-first-order and pseudo-second-order models yielded high R² values from 0.850 to 0.932 and from 0.991 to 0.999, respectively. The meranti sawdust was found to be cost effective and has good efficiency to remove these toxic metal ions from aqueous solution.     

Use of hop (Humulus lupulus) agricultural by-products for the reduction of aqueous lead(II) environmental health hazards

The agricultural by-products of the hop plant (Humulus lupulus L.) were investigated to determine their potential for use in the removal of heavy lead(II) ions from contaminated aqueous solutions. Separate batch laboratory experiments were performed to establish the optimal binding pH, time exposures, and capacity of the metal adsorption for lead(II) ions by dried and ground hop leaves and stems biomass. Results from these studies have shown a pH dependent binding trend from pH 2-6, with optimum binding occurring around pH 5.0. Time dependency experiments showed a rapid adsorption of lead(II) ions within the first 5 min of contact. Binding capacity experiments demonstrated that 74.2mg of lead(II) were bound per gram of leaf biomass. Similarly overall capacity was seen for the leaves and stems. Desorption of 99% of the bound lead(II) ions was achieved by exposing the metal laden biomass to 0.5M sodium citrate. Further experiments were performed with silica-immobilized hop tissues to determine the lead(II) binding ability under flow conditions. Comparison studies were performed with ion-exchange resins to evaluate the binding ability and to gain further insight into the metal binding mechanism. X-ray absorption spectroscopy experiments were also utilized to gain further insight into the possible lead(II) binding mechanism by the hop plant tissue. Results from these studies indicate that carboxyl ligands are involved in the binding of lead(II) from aqueous solution. These findings show that the use of hop agricultural waste products may be a viable alternative, for the removal and recovery of aqueous lead(II) ions from contaminated waters.     

Removal of Cd(II) and Pb(II) ions, from aqueous solutions, by adsorption onto sawdust of Pinus sylvestris

Fixation of heavy metal ions (Cd(II) and Pb(II)) onto sawdust of Pinus sylvestris is presented in this paper. Batch experiments were conducted to study the main parameters such as adsorbent concentration, initial adsorbate concentration, contact time, kinetic, pH solution, and stirring velocity on the sorption of Cd(II) and Pb(II) by sawdust of P. sylvestris. Kinetic aspects are studied in order to develop a model which can describe the process of adsorption on sawdust. The equilibrium of a solution between liquid and solid phases is described by Langmuir model. Scanning electronic microscopy (SEM) coupled with energy dispersive X-ray analysis (EDAX) and X-ray photoelectron spectroscopy (XPS) shows that the process is controlled by a porous diffusion with ion-exchange. The capacity of the metal ions to bind onto the biomass was 96% for Cd(II), and 98% for Pb(II). The sorption followed a pseudo-second-order kinetics. The adsorption of these heavy metals ions increased with the pH and reached a maximum at a 5.5 value. From these results, it can be concluded that the sawdust of P. sylvestris could be a good adsorbent for the metal ions coming from aqueous solutions. Moreover, this material could also be used for purification of water before rejection into the natural environment.     

复合吸附剂麦饭石-壳聚糖的制备及对Zn~(2+)的吸附性能

含重金属离子的废水对人体和环境有极大的影响,采用吸附法对其进行处理,效果较好,但成本高,不易推广.为此,利用麦饭石负载壳聚糖制备了一种价廉的复合吸附剂.通过X射线衍射(XRD)和扫描电子显微镜(SEM)对其结构进行了表征,研究了不同pH值、不同吸附时间、不同吸附剂投加量对复合壳聚糖吸附Zn2+的影响.结果在pH值为6～8、吸附时间为40 min、复合吸附剂的投加量为4.0 g/L的条件下,复合吸附剂对Zn2+的吸附率达到95%以上,达到国家污水综合排放标准.通过对试验数据运用相关数学模型拟合,复合吸附剂对Zn2+的吸附符合Langmuir吸附等温式,其相关系数R2为0.965 1.因而复合吸附剂麦饭石-壳聚糖可有效地处理含锌废水.     

UV-radiation curing of simultaneous interpenetrating polymer network hydrogels for enhanced heavy metal ion removal

Simultaneous interpenetrating polymer network (IPN) hydrogels have been prepared by UV-initiated polymerization of a mixture of acrylamide (AM) and triethylene glycol divinyl ether (DVE-3). The consumption of each monomer upon UV-irradiation was monitored in situ by real-time infrared (RTIR) spectroscopy. The acrylamide monomer AM was shown to polymerize faster and more extensively than the vinyl ether monomer DVE-3, which was further consumed upon storage of the sample in the dark, due to the living character of the cationic polymerization. The IPN hydrogels were used to remove heavy metal ions from aqueous solution under the non-competitive condition. The effects of pH values of the feed solution and the DVE-3 content in the formulation on the adsorption capacity were investigated. The results indicated that the adsorption capacity of the IPN hydrogels increased with the pH values and DVE-3 content in the formulation. Furthermore, the synergistic complexation of metal ions with two polymer networks in the IPN was found in the adsorption studies. Adsorption kinetics and regeneration studies suggested that the IPN hydrogels could be used as fast-responsive and renewable sorbent materials in heavy metal removing processes.     

Facile preparation of magnetic sodium alginate/carboxymethyl cellulose composite hydrogel for removal of heavy metal ions from aqueous solution

A novel magnetic polysaccharide composite hydrogel was successfully constructed by using sodium alginate (SA) and carboxymethyl cellulose (CMC) as the backbone and filled with in situ Fe₃O₄ nanoparticles, which was then employed for removal of heavy metal ion from aqueous solution. The obtained magnetic SA/CMC composite hydrogel was characterized by Fourier transform infrared spectroscopy, fluorescence microscope, thermogravimetric and vibrating sample magnetometer. Effect of contact time, pH and adsorbent dosage on the adsorption of heavy metal ions by the magnetic SA/CMC hydrogel have also been studied. The results show that the prepared magnetic SA/CMC hydrogel can be effectively utilized in the removal of heavy metal ions from aqueous solution. The maximal adsorption capacity of Mn(II), Pb(II), and Cu(II) as calculated from the Langmuir model were 71.83, 89.49, and 105.93 mg/g, respectively. The adsorption process of the magnetic SA/CMC hydrogel on the heavy metal ions can be attributed to ion exchange and chemical adsorption. What’s more, the magnetic hydrogel exhibited high efficiency after four cycles, which indicating it offers great potential for practical application in the removal of heavy metal ions from aqueous solution.