木质素及其衍生物对重金属离子吸附性能研究进展

木质素是一种有机高分子,大量存在于木材、竹材、秸秆、草类及其它植物材料中。但由于其结构复杂,导致应用受到很大的限制。有效利用好木质素这种可再生资源已成为科研工作者研究的出发点。木质素吸附剂是近年来木质素高值化利用研究的热点。文章在简要介绍木质素的化学结构及其分子修饰基础上,对木质素及其衍生物近年来在重金属离子的吸附研究进行了综述。     

改性木质素吸附重金属离子的研究与应用进展

木质素有很强的吸附能力,通过对木质素进行改性,可以提高其对重金属的吸附能力。综述了改性木质素在吸附处理重金属废水中的研究与应用,并展望了木质素基吸附剂在处理重金属废水中的发展趋势。     

磁性生物炭对铅镉离子的吸附动力学

采用水热合成法制备磁性生物炭,利用XRD、FTIR和BET分析磁性生物炭的结构、官能团种类和比表面积,并研究磁性生物炭对Pb⁽²⁺⁾、Cd(2+)、Cd⁽²⁺⁾的吸附机理。结果表明,磁性生物炭含有丰富的含氧官能团和芳香结构,磁性物质为Fe_3O_4颗粒。Pb(2+)的吸附机理。结果表明,磁性生物炭含有丰富的含氧官能团和芳香结构,磁性物质为Fe_3O_4颗粒。Pb⁽²⁺⁾、Cd(2+)、Cd⁽²⁺⁾在磁性生物炭上的吸附是一个高温自发、吸热且熵增的过程,其吸附过程符合准二级动力学方程,表明化学吸附占据优势,吸附过程是由液膜扩散和颗粒内扩散共同控制。Pb(2+)在磁性生物炭上的吸附是一个高温自发、吸热且熵增的过程,其吸附过程符合准二级动力学方程,表明化学吸附占据优势,吸附过程是由液膜扩散和颗粒内扩散共同控制。Pb⁽²⁺⁾在磁性生物炭的吸附机制,主要与含氧官能团(—COOH、—OH、C—O—C)的络合作用和π电子的配位作用有关,还存在氧化还原反应。磁性生物炭吸附Cd(2+)在磁性生物炭的吸附机制,主要与含氧官能团(—COOH、—OH、C—O—C)的络合作用和π电子的配位作用有关,还存在氧化还原反应。磁性生物炭吸附Cd⁽²⁺⁾的机制,主要与—COOH、—OH和π电子的络合作用有关,C—O—C和氧化还原反应不参与磁性生物炭对Cd(2+)的机制,主要与—COOH、—OH和π电子的络合作用有关,C—O—C和氧化还原反应不参与磁性生物炭对Cd⁽²⁺⁾的吸附。     

影响啤酒酵母菌吸附铅离子条件的研究

采用啤酒酵母自制生物吸附剂用于吸附金属铅离子,考察了pH值、反应时间、酵母浓度及金属离子浓度对啤酒酵母吸附Pb2 的影响.单因素实验结果表明,当pH值为5.0、溶液初始Pb2 浓度为80 mg·L-1、啤酒酵母的浓度为1.0 g·L-1、反应时间为0.5 h时,吸附效果最佳.通过正交实验,确定初始Pb2 浓度为反应过程中的显著因素.     

磁性生物炭对铅镉离子的吸附动力学

采用水热合成法制备磁性生物炭,利用XRD、FTIR和BET分析磁性生物炭的结构、官能团种类和比表面积,并研究磁性生物炭对Pb2+、Cd2+的吸附机理.结果表明,磁性生物炭含有丰富的含氧官能团和芳香结构,磁性物质为Fe3 O4颗粒.Pb2+、Cd2+在磁性生物炭上的吸附是一个高温自发、吸热且熵增的过程,其吸附过程符合准二...     

巯基木质素的制备及其对重金属离子的吸附

以工业硫酸盐木质素（LS）为原料,合成一种新型重金属离子吸附剂-巯基木质素（LS-SH）。通过红外光谱表征其结构,推测反应机理;研究LS-SH对重金属离子Cu^2＋、Pb^2＋、Cd^2＋的静态吸附性能,结果表明LS-SH是一种价廉、高效的重金属离子吸附荆,其吸附量是原料LS的5～7倍。     

黑藻对镉离子的生物吸附研究

研究了黑藻对镉离子的吸附作用,考察了溶液pH、镉离子初始浓度、吸附剂用量和吸附时间等因素对吸附的影响.在选定的吸附条件下,即pH为6.0,吸附剂用量为2 g·L-1,吸附时间为120 min时,对于50 mg·L-1的Cd+溶液,黑藻对Cd+的吸附效率为96%,吸附量为24.1 mg·g-1.常温下黑藻对Cd+的吸附作用可用Langmiur、Freundlich和Dubinin-Radushkevich(D-R)等温吸附模型进行拟合,相关系数r2分别达到0.9852、0.9901和0.9982,说明吸附反应符合这三种吸附模型.     

硫酸钙晶须对镉镍铅离子的吸附性能

以原子吸收分光光度计为分析手段,研究了CaSO4晶须对镉、镍、铅离子吸附性能。研究表明：铅离子在pH值为3～13范围内均可被CaSO4晶须定量吸附,尤其在pH值为8、振荡时间为2h时,吸附率高达77．89％;而对镉和镍两种金属离子几乎没有吸附作用。     

纳米TiO2对铅镉离子的吸附性能研究

研究了纳米TiO2吸附和解吸附铅镉离子的条件。吸附条件为pH为7-8,超声波振荡3-5 min,解吸附条件为0．12 mol/LHCl进行洗脱,温度50℃,此时吸附率和解吸附率均高于98％。结果表明:吸附存在可逆吸附和不可逆吸附过程,吸附等温线类于朗格缪尔吸附,经线性回归计算出吸附方程、吸附平衡常数、最大吸附容量;不可逆吸附容量与纳米TiO2 表面氧原子有关;可逆吸附与表面羟基有关,而两者均受晶体结构影响,比表面积不是影响吸附容量大小的主要因素。在试验的基础上推断了两种吸附过程的模型。     

溶剂分级木质素对ABE发酵液吸附分离性能

运用溶剂分级的方法制备成本低廉、环境友好型木质素基吸附材料,探究了其对ABE发酵液的吸附分离性能。研究发现经丙酮溶解分级后的丙酮不溶木质素(AIAL)具有良好的吸附性能。吸附动力学实验表明AIAL的动态吸附过程在40 min可以达到平衡,数据可用Lagergren拟一级动力学模型拟合;等温吸附实验表明AIAL对丁醇、丙酮和乙醇饱和吸附量分别为198,151.3和98.5 mg/g,较分级前提升了19.3%,30.2%和53.2%,数据可用Langmuir-Freundlich模型拟合;模拟发酵液中的吸附实验表明丁醇、丙酮和乙醇之间竞争吸附作用较小;脱附液中ABE质量浓度达到90.75 g/L;表征分析结果表明:AIAL和丁醇、丙酮和乙醇容易形成π体系。     

Adsorption performance of nickel and cadmium ions onto brewer's yeast

The brewer's yeast was used as adsorbent for the removal of Ni(II) and Cd(II) metal ions from aqueous solution. The surface of the brewer's yeast had three main functional groups of sulfonate, carboxyl, and amine groups. The pH of solution played an important role on the uptake of metal ions, and optimum adsorption was obtained at pH 6. Acid solution (pH 3) was efficient for the desorption of Ni(II) and Cd(II) ions from loaded brewer's yeast and the desorption efficiency was higher than 90%. The rate of metal ions adsorption onto brewer's yeast was rapid with short contact time. The kinetics of the adsorption process was found to follow the pseudo‐second‐order kinetic model. Langmuir and Freundlich isotherm models were used to fit the experimental data with Langmuir isotherm model having a better fit. The maximum uptakes of Ni(II) and Cd(II) by brewer's yeast were estimated to be 5.34 and 10.17 mg/g, respectively.     

Adsorption kinetics of cadmium ions onto powdered corn cobs

Environmental pollution caused by the presence of toxic materials such as cadmium is becoming global problem and concern. This paper presents a report on kinetics of Cd²⁺ removal from aqueous solutions through adsorption using powdered corn cobs (PCC). Corn cobs were collected from a selected location, washed to remove sand, air dried, ground and sieved into different particle sizes. The selected properties of PCC were determined using acid digestion method. Adsorption capacities through kinetics of Cd²⁺ removal from synthetic solutions, typical raw water and domestic‐institutional wastewater were studied. Effects of pH, PCC particle size, initial concentration of Cd²⁺ and temperature on adsorption capacities were monitored through pseudo first‐ and second‐order models, Elovich and intraparticle diffusion models to present adsorption rate parameters. The study revealed that PCC contained 86.89% volatile solids, had 4.56% acid solubility, 0.52 water solubility and 2.33% ash content. PCC removed Cd²⁺ from aqueous solutions (synthetic, raw water, and wastewater). The relationship between time and concentration of Cd²⁺ remaining in the solution followed exponential functions with squared correlation coefficient ranging from 0.9928 to 0.9993, 0.8701 to 0.9284, and 0.8514 to 0.9290 for synthetic solution, raw water, and typical domestic‐institutional wastewater, respectively. Mechanism of cadmium adsorption onto PCC was in two separate stages linear portions in the first parts, while the final parts are curves indicating intraparticle diffusion. It was concluded that PCC is an effective adsorbent for Cd²⁺ removal. The estimated production cost was 0.068 USD as against 0.50, 2.12, and 3.12 USD for producing adsorbents from empty fruit bunches; pencom shell and sugar cane based activated carbons, respectively.     

Intraparticle diffusion of cadmium and zinc ions during adsorption from aqueous solution on activated carbon

The adsorption isotherms of cadmium(II) and zinc(II) onto activated carbons were obtained in a batch adsorber. The concentration decay data were obtained in a rotating basket adsorber and were interpreted by a mathematical model, which takes into account the adsorption rate, external mass transport and intraparticle diffusion. The results showed that the overall rate of adsorption of Cd(II) and Zn(II) was mainly controlled by the intraparticle diffusion which was solely due to pore volume diffusion. The contribution of the external mass transport resistance was negligible. The effective pore volume diffusivities of Cd(II) and Zn(II) were predicted reasonably well using the ionic diffusivity of the metal and the void fraction and tortuosity of activated carbon. Copyright © 2005 Society of Chemical Industry     

Adsorption for metal ions of chitosan coated cotton fiber

A kind of adsorbent for metal ions, cotton fiber coated by high loading of chitosan (SCCH) was prepared. Its structure was characterized by elemental analysis, scanning electronic microscopy (SEM), Fourier transform infrared spectrum (FTIR), and wide‐angle X‐ray diffraction (WAXD). The adsorption properties of SCCH for Cu²⁺, Ni²⁺, Pb²⁺, Cd²⁺, such as saturated adsorption capacities, static kinetics, and isotherm were investigated. The adsorption for Ni²⁺, Pb²⁺, and Cd²⁺ was controlled by liquid film diffusion, but by particle diffusion for Cu²⁺. The adsorption process for Cu²⁺, Ni²⁺, Cd²⁺ could be described with Langmuir or Freundlich equation, but only with Freundlich equation for Pb²⁺. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

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。     

Adsorption of Rhodamine B onto O-Carboxymethylchitosan-N-Lauryl

The adsorption of a cationic dye (rhodamine B; RB) on O-carboximethyl-N-acetylated (L-CMCh) in aqueous solution was investigated. The effect of the process parameters such as the contact time, pH, and temperature are reported. Both temperature and pH influence dye adsorption. To determine the adsorption capacity, the equilibrium adsorption data were analyzed by the Langmuir, Langmuir-Freundlich, and Redlich-Peterson isotherm models. The results showed better agreement with the Langmuir-Freundlich model than the other models. The maximum adsorption capacity of RB for L-CMCh was determined as 38.5 mg g^?1 at pH 8.5 and 25°C. The kinetic results follow a pseudo-second-order rate equation. The activation energy value for adsorption of RB on L-CMCh was found to be 52.0 kJ mol^?1. The negative values of Gibbs free energy and enthalpy show the adsorption to be spontaneous and exothermic. The negative value of the enthalpy for adsorption of RB onto L-CMCh shows the adsorption to be exothermic.     

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。     

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。     

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％、     

分子印迹吸附剂对红景天水煎液中重金属的吸附

采用分子印迹技术,以Pb（Ⅱ）为印迹离子制备了铅印迹壳聚糖包覆硅藻土微球（PbCSDE）。研究了PbCSDE对红景天水煎液中重金属Pb（Ⅱ）、Cu（Ⅱ）的吸附,考察了吸附时间、溶液pH对吸附的影响。与732商业树脂比较,铅印迹壳聚糖包覆硅藻土微球（PbCSDE）对红景天水煎液中Pb（Ⅱ）、Cu（Ⅱ）的吸附能力提高了2倍多。紫外光谱和高效液相色谱分析表明,经PbCSDE吸附后,红景天水煎液中的活性成分红景天苷没有发生改变。