Competitive removal of heavy metal ions by cellulose graft copolymers

The effect of composition of graft chains of four types cellulose graft copolymers on the competitive removal of Pb²⁺, Cu²⁺, and Cd²⁺ ions from aqueous solution was investigated. The copolymers used were (1) cellulose‐g‐polyacrylic acid (cellulose‐g‐pAA) with grafting percentages of 7, 18, and 30%; (2) cellulose‐g‐p(AA–NMBA) prepared by grafting of AA onto cellulose in the presence of crosslinking agent of N,N′‐methylene bisacrylamide (NMBA); (3) cellulose‐g‐p(AA–AASO₃H) prepared by grafting of a monomer mixture of acrylic acid (AA) and 2‐acrylamido‐2‐methyl propane sulphonic acid (AASO₃H) containing 10% (in mole) AASO₃H; and (4) cellulose‐g‐pAASO₃H obtained by grafting of AASO₃H onto cellulose. The concentrations of ions which were kept constant at 4 mmol/L in an aqueous solution of pH 4.5 were equal. Metal ion removal capacities and removal percentages of the copolymers was determined. Metal ion removal capacity of cellulose‐g‐pAA did not change with the increase in grafting percentages of the copolymer and determined to be 0.27 mmol metal ion/g_copolymer. Although the metal removal rate of cellulose‐g‐p(AA–NMBA) copolymer was lower than that of cellulose‐g‐pAA, removal capacities of both copolymers were the same which was equal to 0.24 mmol metal ion/g_copolymer. Cellulose did not remove any ion under the same conditions. In addition, cellulose‐g‐pAASO₃H removed practically no ion from the aqueous solution (0.02 mmol metal ion/g_copolymer). The presence of AASO₃H in the graft chains of cellulose‐g‐p(AA–AASO₃H) created a synergistic effect with respect to metal removal and led to a slight increase in metal ion adsorption capability in comparison to that of cellulose‐g‐pAA. All types of cellulose copolymers were found to be selective for the removal of Pb²⁺ over Cu²⁺ and Cd²⁺. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 90: 2034–2039, 2003     

细菌纤维素对重金属离子的吸附机理研究

以细菌纤维素(BC)为吸附剂,对重金属离子Cu2+,Pb2+和Cd2+的吸附等温线和吸附动力学特性进行了研究,并采用红外光谱分析法探讨了吸附作用机理。结果表明:BC对Cu2+,Pb2+和Cd2+吸附更好地符合Langmuir吸附等温方程和准二级反应动力学模型,说明吸附过程为单分子层吸附,化学吸附作用为主。粒子内扩散拟合曲线均不经过原点,证明粒子内扩散并不是唯一速率控制步骤。FT-IR分析表明吸附金属离子后的BC中—OH最大吸收位发生不同程度的蓝移,说明BC中部分—OH参与吸附,即与重金属离子之间发生反应,从而使—OH的数量减少。     

Functional copolymers with retention properties for heavy metal ions

Summary Poly (N-phenylmaleimide-co-2-methylaziridine); poly [p-methylphenyl-maleimide-co-1-(2-hydroxyethyl)aziridine]; poly [p-methoxyphenylmaleimide-co-1-(2-hydroxyethyl)aziridine] and poly [N-phenylmaleimide-co-1-(2-hydroxyethyl)aziridine] were synthesized by spontaneous coplymerization. All the resins were insoluble in water. It was found that the resins with 1-(2-hydroxyethyl)aziridine moiety showed the highest adsorption ability for uranium.     

磺化煤对重金属离子的吸附效果研究

磺化煤是一种价格低廉、原料广泛的具有较强吸附性能的新型吸附剂。介绍了磺化煤的制备方法采用静态法测定了磺化煤对几种重金属离子的吸附量,结果显示吸附量的顺序为Pb^2 ＞Cu^2 ＞Ni^2 ＞Zn^2 。研究了吸附时间、pH值对吸附量的影响及磺化煤在电镀废水处理中的实际应用效果,探讨了磺化煤吸附重金属离子的机理。结果表明,pH值是影响磺化煤吸附作用的主要因素,且其对实际电镀废水的吸附净化效果较好,对重金属的去除率高达99％、     

Hydrogel beads based on carboxymethyl cellulose for removal heavy metal ions

Environment‐friendly carboxymethyl cellulose (CMC) hydrogel beads were successfully prepared using epichlorohydrin (ECH) as a crosslinking agent in the suspension of fluid wax. There was an ether linkage formed between ECH and CMC, which was identified from bands in FTIR spectra of the prepared hydrogel. The prepared hydrogel beads with diameters about 4 mm were apparently spherical and fully transparent. The X‐ray diffraction (XRD) spectra indicated that the adsorption of metal ion onto the oxygen atom of carboxyl group led to change in crystallinity patterns of hydrogels. The scanning electron microscope (SEM) images clearly showed that the hydrogels had an internal porous structure. The adsorption capacity increased as initial concentrations of metal ions and the pH value of metal ion solution increased. Freundlich and Langmuir isotherm models were employed to analyze the data from batch adsorption experiments. There are vey good correlation coefficients of linearized equations for Langmuir model, which indicated that the sorption isotherm of the hydrogel beads for metal ions can be fitted to the Langmuir model. The maximum adsorption amount of hydrogel beads for metal ions is 6.49, 4.06, and 5.15 mmol/g for Cu(II), Ni(II), and Pb(II), respectively. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Thermal behavior of graft copolymers of cotton cellulose and acrylate monomers

Cotton cellulose yarn was grafted with methyl acrylate, ethyl acrylate, n-butyl acrylate, and methyl methacrylate at various percentages of grafting. The effects of concentration of the initiator, concentration of the acid, and of temperature on grafting was studied and the mechanism discussed. The effect of reactivity of the monomer on the percentage graft-on is pointed out. Thermal behavior of natural and grafted cotton yarn was studied using dynamic thermogravimetry in air at a heating rate of 6°C/min up to a temperature of 500°C. The thermal stabilities of the samples grafted with various acrylate monomers to various percentages of grafting were computed from their primary thermograms by calculating the values of IDT, IPDT, and E^*. The results show that the thermal stability increases with increase in graft-on per cent, and the thermal stabilities of natural cotton and cotton grafted with different monomers are in the order ethyl > methyl > natural cellulose > methyl methacrylate > n-butyl acrylate.     

颗粒赤泥吸附剂对重金属离子的吸附性能研究

以氧化铝生产产生的工业固废——赤泥为原料,采用生石灰熟化后煅烧造粒方法,制备了颗粒状赤泥吸附材料。将制得的吸附材料用于水体中Cu2+、Pb2+、Cd2+的去除。研究了吸附时间、溶液pH值、吸附剂投加量对吸附效果的影响,在吸附作用时间、pH值、投加量相同的情况下,颗粒赤泥对3种金属离子的去除效果的大小顺序为Pb2+、Cd2+、Cu2+。颗粒赤泥吸附材料对3种金属离子的等温吸附规律可分别用Langmuir等温式、Langmuir等温式和Freundlich等温式较好地进行描述。颗粒赤泥吸附剂对3种重金属离子吸附饱和容量大,达平衡时间短,具较好的吸附性能。     

啤酒酵母对重金属离子的吸附和解吸效果影响的实验研究

以固定化的啤酒酵母作为生物吸附剂,海藻酸钠和聚乙烯醇作为包埋剂,研究了pH值、ρ(初始重金属离子)、ρ(菌体)、吸附时间、吸附温度对吸附Pb2+、Cu2+、Zn2+和Cd2+的影响,并进行了解吸剂及其质量浓度对固定化啤酒酵母解吸影响的研究.研究结果表明,在pH值=5.5,ρ(菌体)=20 g/L,吸附时间2h,吸附温度...     

改性煤气化灰渣吸附重金属离子的研究

以煤气化灰渣为原料,采用酸改性法(HF酸)制备改性煤气化灰渣。通过静态实验研究了改性煤气化灰渣对溶液中Pb⁽²⁺⁾、Cu(2+)、Cu⁽²⁺⁾、Cd(2+)、Cd⁽²⁺⁾的吸附特性,测定了溶液pH值、吸附时间、金属离子初始浓度对吸附的影响。结果表明,二级动力学方程很好的描述溶液中重金属离子在改性煤气化灰渣上的吸附过程;吸附等温线符合Langmuir模型,Pb(2+)的吸附特性,测定了溶液pH值、吸附时间、金属离子初始浓度对吸附的影响。结果表明,二级动力学方程很好的描述溶液中重金属离子在改性煤气化灰渣上的吸附过程;吸附等温线符合Langmuir模型,Pb⁽²⁺⁾、Cu(2+)、Cu⁽²⁺⁾、Cd(2+)、Cd⁽²⁺⁾的静态饱和吸附量分别为112.07,40.18,31.21 mg/g。     

改性煤气化灰渣吸附重金属离子的研究

以煤气化灰渣为原料,采用酸改性法(HF酸)制备改性煤气化灰渣。通过静态实验研究了改性煤气化灰渣对溶液中Pb~(2+)、Cu~(2+)、Cd~(2+)的吸附特性,测定了溶液pH值、吸附时间、金属离子初始浓度对吸附的影响。结果表明,二级动力学方程很好的描述溶液中重金属离子在改性煤气化灰渣上的吸附过程;吸附等温线符合Langmuir模型,Pb~(2+)、Cu~(2+)、Cd~(2+)的静态饱和吸附量分别为112.07,40.18,31.21 mg/g。     

不同变质程度超微煤粉对重金属离子的吸附性能

重金属离子由于具有毒性、难以生物降解且可在生物体内累积,严重威胁人类的身体健康。吸附是去除重金属离子的一种可行有效的方法。本文选择褐煤、烟煤、无烟煤3种变质程度不同的煤种,通过高能球磨获得超微煤粉。研究了3种超微煤粉对水溶液中Ni²⁺和Cr⁶⁺的吸附动力学与热力学以及投加量与pH值对吸附效果的影响。结果表明3种煤粉对Ni²⁺、Cr⁶⁺的吸附量均随时间的增加而增加,并且Ni²⁺的处理效果明显好于Cr⁶⁺,在180min时褐煤、无烟煤与烟煤对Ni²⁺、Cr⁶⁺的吸附量分别为3.906mg/g、3.582mg/g、2.983mg/g和1.953mg/g、1.774mg/g、0.487mg/g。3种煤粉对两种重金属离子的吸附均符合二级吸附动力学和Freundlich等温式,随着投加量与pH值的增加,去除效果增加,在相同条件下,褐煤的吸附效果优于烟煤与无烟煤。     

Adsorption behavior of metal ions by amidoxime chelating resin

The adsorption properties of poly(acrylamidoxime) chelating resin for Cu(II), Cd(II), Hg(II), Zn(II), Pb(II), Cr(III), and U(VI) are investigated by the batch technique. Based on the research results of the binding capacity effect of the pH value on sorption kinetic experiments, it is shown that this resin has higher binding capacity to uranyl ions, fast kinetics, and very good selectivity from binary metal ion mixtures with Cu(II) and Pb(II). The uranyl ion sorption strongly depends on the pH value of the solution. The highest value of 99% is at pH 5, but at pH 1 there is no retention. The adsorbed UO can be eluted by sulfuric acid and sodium carbonate. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1994–1999, 2000     

Preparation of mercaptoethylated graft fibers for adsorption of heavy metal ions

Various kinds of mercaptoethylated graft fibers were prepared and the abilities to adsorb the heavy metal ions were studied. 2-Hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, and vinyl acetate were graft-copolymerized by irradiation onto five kinds of synthetic fibers and two kinds of foam polymers. Preirradiation at low temperature was far more effective for grafting than simultaneous irradiation. The mercaptoethylation was carried out in the solution or in the vapor of ethylene sulfide onto the graft fibers treated with alkali. The mercaptoethylated graft fibers showed particular affinity for Hg and Ag ions. A few of the adsorption phenomena were pursued by flow experiment of the ionic solution through a column. The preliminary reduction of the mercaptoethylated graft fibers enhanced the capacity of adsorbing to three times that of the unreduced fibers. Effects of flow rate, pH, temperature, and concentration of Hg ion on the integrated adsorbed amount were also investigated.     

羽毛纤维对废水中重金属离子的吸附性能研究

利用禽类羽毛纤维作为吸附剂,吸附溶液中的重金属离子Cu~(2+)、Zn~(2+)、Ni~(2+)、Pb~(2+)、Cr~(6+)。考察温度、pH值、吸附剂投加量、重金属离子初始浓度等对羽毛纤维吸附效果的影响并建立吸附等温线。结果表明,羽毛纤维能吸附重金属离子,随着温度、吸附剂投加量的增大,重金属离子初始浓度的降低,羽毛纤维对重金属离子的吸附率逐渐提高。随着pH值的升高,羽毛纤维对Cu~(2+)、Zn~(2+)、Ni~(2+)、Pb~(2+)的吸附率提高,对Cr~(6+)的吸附率降低。羽毛纤维对Cu~(2+)、Zn~(2+)、Ni~(2+)、Pb~(2+)吸附符合Freundlich吸附等温模型。羽毛纤维对重金属离子的吸附能力顺序为Pb~(2+)>Cu~(2+)>Zn~(2+)>Ni~(2+)>Cr~(6+)。     

巯基壳聚糖对重金属离子的配合吸附性能

制备了巯基壳聚糖(CTS-SH)和环氧氯丙烷交联的壳聚糖(CCTS),对比研究了CTS-SH、CCTS和母体壳聚糖(CTS)对Hg2、Pb2 、Cd2 、Pd2 几种重金属离子的吸附能力和选择性。结果表明CTS-SH较CCTS和CTS有较高的吸附容量和很好的吸附选择性,与预期的效果一致。     

Adsorption of heavy metal ions from aqueous solution by fly ash

The removal characteristics of lead and copper ions from aqueous solution by fly ash were investigated under various conditions of contact time, pH and temperature. The influence of pH of the metal ion solutions on the uptake levels of the metal ions by fly ash were carried out between pH 4 and 12. The level of uptake of Pb²⁺ and Cu²⁺ ions by the fly ash generally increased, but not in a progressive manner, at higher pH values. The effect of temperature on the uptake of Pb²⁺ and Cu²⁺ ions was investigated between 30 °C and 60 °C, the adsorption of being enhanced at the lowest temperature. Rate constants were evaluated in terms of a first-order kinetics. The rate constant, k for uptake of Pb²⁺ and Cu²⁺ ions were 1.77 × 10⁻² s⁻¹ and 2.11 × 10⁻² s⁻¹, respectively. The experimental results underline the potential of coal fly ash for the recovery of metal ions from waste water. The main mechanisms involved in the removal of heavy metal ions from solution were adsorption at the surface of the fly ash and precipitation.     

Adsorption of some heavy metal ions from aqueous solutions on Nafion 117 membrane

Nafion 117 membrane was investigated for the removal of Ni(II), Co(II), Pb(II), Cu(II) and Ag(I) metal ions from their synthesized aqueous solutions. The different variables affecting the adsorption capacity of the membrane such as contact time, initial metal ion concentration in the feed solution, pH of the sorption medium and temperature of the solution were investigated on a batch sorption basis. The affinity of Nafion 117 membrane towards heavy metal ions was found to increase in the sequence of Cu(II), Ni(II), Co(II), Pb(II), and Ag(I) with adsorption equilibrium achieved after 30 min for all metal ions. Among all parameters, pH has the most significant effect on the adsorption capacity, particularly in the range of 3.1-5.9. The variation of temperature in the range of 25-65 °C was found to have no significant effect on the adsorption capacity. Nafion 117 membrane was found to have high stability combined with repeated regeneration ability and can be suggested for effective removal of heavy metal ions such as Cu(II), Ni(II) and Co(II) from aqueous solutions.     

Adsorption of heavy metal ions from aqueous solutions by porous polyacrylonitrile beads

The adsorption of Cu(II), Ni(II), Zn(II), and Pb(II) from aqueous solutions on acrylonitrile copolymer sorbents was studied. We prepared five types of sorbents from polyacrylonitrile by varying its concentration in the initial polymer solution and the composition of the coagulation bath, aiming to achieve a different porous structure. The specific area, pore volume, and pore radius of the sorbents were determined on a porosimeter. The porous structure was studied by scanning electron microscopy. Modification of sorbents with sodium hydroxide and hydroxylamine was carried out to form amidooxyme and carboxylic groups with proven complex‐forming properties toward heavy metal ions. The optimal pH of the sorption of metal ions was found. The adsorption kinetics were investigated. The order of polymer sorbents toward the sorption of Pb(II), Cu(II), Ni(II), and Zn(II) ions, and the order of heavy metal uptake were determined for all types of sorbents. The effectiveness of heavy metal desorption and the coefficient of recovery of sorption ability were determined. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 3036–3044, 2002; DOI 10.1002/app.2334