纤维素的改性及对重金属离子去除的研究进展

本文在对纤维素的性质、结构和来源进行介绍的基础上,重点阐述了近年来国内外对纤维素改性的方法,其中包括醚化反应、酯化反应、接枝共聚反应和模板合成等.同时进一步总结了纤维素基吸附材料在含重金属离子废水中应用的研究进展.     

Competitive adsorption of heavy metal ions (Pb2+, Cu2+, and Ni2+) onto date seed biochar: batch and fixed bed experiments

In a multicomponent systems, the adsorption of Pb²⁺, Cu²⁺, and Ni²⁺ by date seed biochar exhibited competitive behavior. Compared to single component systems, the adsorption capacities of each ion were reduced by 48–75% in both batch and column experiments. Surface complexation with carboxyl and hydroxyl functional groups played a major role in the removal mechanism. Ion exchange mechanism accounted for 37–40% of the total adsorption compared to 57–72% in single component systems. Modified Langmuir isotherm best described the systems. Adsorption capacities and selectivity follow the order: Pb²⁺> Cu²⁺> Ni²⁺. Multi-stage sequences system is recommended to avoid premature exhaustion of biochar.     

菌丝体-甲壳素水处理剂对重金属离子吸附性能的研究

The adsorption properties of chitin adsorbent from mycelium of fermentation industries for the removal of heavy metal ions were studied.The result shows that the chitin adsorbent has high adsorption capacity for many heavy metal ions and Ni^2 in citric acid.The influence of pH was significant:When pH is higher than 4.0,the high adsorption capacity is obtained.otherwise H^ ion inhibits the adsorption of heavy metal ions.The comparison of the chitin adsorbent with some other commercial adsorbents was made,in which that the adsorption behavior of chitin adsorbent is close to that of commercial cation exchange adsorbents,and its cost is much lower than those commercial adsorbents.     

重金属离子吸附材料的研究进展

综述了以无机吸附材料（碳质类、矿物类和金属氧化类）、高分子吸附材料（人工合成高分子材料和天然高分子材料）和复合型吸附材料（有机/有机型、有机/无机型和无机/无机型）为代表的重金属离子吸附材料的结构特征和吸附性能。重点介绍了离子选择性吸附材料（螯合型吸附材料和离子印迹型吸附材料）和可降解生物质基离子吸附材料（纤维素、壳聚糖、木质素和农林废弃物）等新型重金属离子吸附材料的研究进展,同时展望了重金属离子吸附材料的发展方向。     

壳聚糖对痕量重金属离子铅、铬、镍的吸附研究

本文研究了重金属捕集剂壳聚糖对痕量重金属Pb2 、Cr3 、Ni2 离子的吸附作用。实验结果表明,壳聚糖对痕量重金属的吸附率与壳聚糖的用量、pH值、吸附时间、壳聚糖的脱乙酰度有关。在常温下,0.2 g的脱乙酰度为80%的CS在pH=7时,对Pb(Ⅱ)、Cr(Ⅲ)、Ni(Ⅱ)的吸附率分别为94.2%,54.3%,90.6%。     

改性泥炭对Pb2+、Ni2+、Cu2+的吸附性能研究

在静态条件下,研究了改性泥炭对重金属离子Pb2+、Ni2+、Cu2+的吸附性能,着重探讨了改性泥炭去除废水中重金属离子Pb2+、Ni2+、Cu2+的适宜条件,同时对改性泥炭的吸附及解吸再生机理进行了初步分析。结果表明:在25℃条件下,当pH值为5～7、吸附剂用量为2g/L、吸附时间为2h时,改性泥炭对Pb2+、Ni2+、Cu2+的去除率分别为98.0%、96.7%、95.5%。吸附了重金属离子的改性泥炭经酸解吸再生后,可循环使用,不会带来二次污染。     

蒙脱石和高岭石吸附水溶液中重金属离子的实验研究

综述了近几年研究人员以蒙脱石、高岭石和膨润土作为吸附材料,去除水溶液中的砷、镉、铬、铜、铅几种重金属离子。通过酸性活化改性,有机分子嫁接改性,纳米氧化物涂层和柱撑等手段,提高了粘土矿物的吸附性能,达到更好的吸附效果。结果表明有机改性更有利于蒙脱石等粘土矿物对于重金属离子的吸附,同时指出pH是影响吸附效果的关键因素。     

废啤酒酵母同步吸附水中Pb2+、Zn2+、Cd2+的研究

利用废啤酒酵母同步吸附处理含Pb2+、Zn2+、Cd2+废水,考察了初始pH、反应时间和初始浓度等因素对去除率的影响,并对吸附动力学进行探讨.结果表明:废啤酒酵母对Pb2+、Zn2+、Cd2+同步吸附去除率大小依次为Pb2+＞Cd2+＞Zn2+;三者之间存在竞争吸附;拟二级动力学方程相关系数R2＞0.99,对Pb2+和在低浓度条件下拟合情况更好,内扩散和液膜扩散联合控制吸附速率.     

Competitive Adsorption of Ag+, Pb2+, Ni2+, and Cd2+ Ions on Vermiculite

Competitive adsorption of Ag⁺, Pb²⁺, Ni²⁺, and Cd² ions on vermiuculite in a binary, ternary, and quaternary mixture was investigated in batch experiments. The effects of the presence of Ag⁺, Ni²⁺, and Cd²⁺ ions on the adsorption of Pb²⁺ ions were investigated in terms of the equilibrium isotherm. Experimental results indicated that Pb²⁺ ions always favorably adsorbed on vermiculite over Ag⁺, Ni²⁺, and Cd²⁺ ions. The adsorption equilibrium data of Pb²⁺ ions better fitted the Langmuir model than the Freundlich model. The results showed that the pseudo-second-order kinetics model was in good agreement with the experimental results for all metal ions, and the adsorption rate among the metal ions followed Ag⁺ > Pb²⁺ > Ni²⁺ > Cd²⁺. The desorption and regenration study indicated that vermiculite can be used repeatedly and be suitable for the design of a continuous process.     

Removal of Cd2+, Cu2+, Ni2+, and Pb2+ ions from aqueous solutions using tururi fibers as an adsorbent

This work investigates the removal of Cd²⁺, Cu²⁺, Ni²⁺, and Pb²⁺ ions from aqueous solutions using tururi fibers as an adsorbent under both batchwise and fixed‐bed conditions. It was found that modification of the tururi fibers with sodium hydroxide increased the adsorption efficiencies of all metal ions studied. The fractional factorial design showed that pH, adsorbent mass, agitation rate, and initial metal concentration influenced each metal adsorption differently. The kinetics showed that multi‐element adsorption equilibria were reached after 15 min following pseudo‐second‐order kinetics. The Langmuir, Freundlich, and Redlich–Peterson models were used to evaluate the adsorption capacities by tururi fibers. The Langmuir model was found to be suitable for all metal ions. Breakthrough curves revealed that saturation of the bed was reached in 160.0 mL with Cd²⁺ and Cu²⁺, and 52.0 mL with Ni²⁺ and Pb²⁺. The Thomas model was applied to the experimental data of breakthrough curves and represented the data well. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40883.     

改性黏胶纤维对重金属离子的吸附性能研究

将黏胶纤维在一定条件下进行羧甲基化改性,探讨了改性黏胶纤维对重金属离子Cu2+、Ni2+的吸附性能,以及黏胶的取代度、pH值、吸附温度及吸附时间对吸附性能的影响,同时研究了吸附动力学。结果表明,改性黏胶对两种离子都有良好的吸附性能,其中Ni2+的最佳吸附条件为:pH=5,温度50℃,饱和吸附量167 mg/g;Cu2+的最佳吸附条件为:pH=4~5,饱和吸附量108 mg/g;吸附重金属离子的改性黏胶纤维在pH<2时迅速解析,可循环利用。     

Water Purification from Heavy Metal Ions in a Packed Column

The process of adsorption from water solutions containing ternary system of Cu(II), Zn(II) and Ni(II) ions in time-variable conditions in a packed column with lyophilized chitosan beads is considered. The system of partial differential equations describing the adsorption column, due to the assumption of a properly defined variable is transformed into a system of ordinary nonlinear equations which enables the identification of object parameters in simple experiments. Analytical solution of that system was possible due to the assumptions made regarding the equation describing sorption kinetics. Using experimental data, the effective diffusion coefficient D_eff and the sorption kinetic constants K in the real environment were identified. The sorption capacity q* was obtained in separate sorption equilibrium experiments. Using a mathematical model the influence of initial concentration and solution flow rate on the breakthrough curve was determined. The approach which is presented provides a new method for modeling of sorption in a packed column.     

泥炭对重金属废水中Cu^2＋、Pb^2＋最佳吸附条件的研究

泥炭中富含有机质与腐植酸,其中含有大量的极性基团,对金属离子有较强的吸附性能。本试验通过对泥炭吸附重金属废水中Cu^2＋、Pb^2＋种离子的吸附条件进行研究,得出最佳吸附条件为：当重金属离子浓度为30mg／L时,泥炭投加量分别为7g／L和5g／L,最佳吸附pH值分别为5和8,吸附时间均为30min．且离子浓度越高,表观吸附量越大,但除金属率越低。最佳条件下Cu^2＋、Pb^2＋的表观吸附量分别为4．24mg／g和6．00mg／g,除铜率和除铅率分别为98．8％和999％。     

Microwave preparation and properties of O-crosslinked maleic acyl chitosan adsorbent for Pb2+ and Cu2+

A novel chitosan-based adsorbent (CCTM) was prepared by the reaction of epichlorohydrin O-crosslinked chitosan with maleic anhydride under microwave irradiation. The chemical structure of this polymer was characterized by infrared spectroscopy and X-ray diffraction analyses. The effects of various variables such as degree of substitution, adsorption time, initial metal ion concentration, solution pH, and temperature, on the adsorption of Pb²⁺ and Cu²⁺ by CCTM were investigated. The results demonstrate that the microwave irradiation can remarkably enhance the reaction. CCTM has higher adsorption capacity than chitosan. The maximum adsorption capacities for Pb²⁺ and Cu²⁺, with initial concentrations of 0.02 mol L⁻¹ at pH 5, are 246.3 and 132.5 mg g⁻¹, respectively. The adsorbent can be recycled. These results have important implications for the design of effective chitosan-based adsorbents in the removal of heavy metal ions from wastewaters. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

聚丙烯酸改性凹土对Pb2+、Ni2+和Cr3+的选择性吸附

通过凹土的表面功能化开发高性能低成本的吸附材料,采用溶液聚合法在其表面接枝聚丙烯酸,制备出聚丙烯酸/凹土吸附材料(PAA/ATP),系统考察了PAA/ATP对Pb²⁺、Ni²⁺和Cr³⁺三元混合体系的吸附性能。结果表明:PAA/ATP复合吸附材料的有机物接枝率为14.1%,其结构中出现聚丙烯酸的特征官能团;PAA/ATP吸附Pb²⁺的动力学符合拟二级动力学,即化学吸附是速率控制步骤,说明PAA/ATP对Pb²⁺的吸附是一个有化学作用的过程,吸附过程与Pb²⁺和吸附剂PAA/ATP表面官能团之间的电子转移或电子共用有关;PAA/ATP对Pb²⁺的吸附符合Langmuir吸附等温模型;PAA/ATP对Pb²⁺、Ni²⁺和Cr³⁺的竞争吸附能力依次为Pb²⁺ > Cr³⁺ > Ni²⁺,即对Pb²⁺具有较好的选择性吸附。     

Papain Adsorption on Chitosan-Coated Nylon-Based Immobilized Metal Ion (Cu2+, Ni2+, Zn2+, Co2+) Affinity Membranes

A novel immobilized metal affinity membrane was prepared for papain adsorption in this article. Higher papain adsorption capacity between 43-67 mg/g was observed and the adsorption isotherm fitted the Freundlich equation. Experimental data were analyzed using two adsorption kinetic models. The pseudo-second-order kinetic model provided better correlation to the experimental results. A significant amount of the adsorbed papain was eluted by 1.0 M NaSCN at pH 5.0 for all affinity membranes. It was concluded that the novel chitosan-coated nylon-based immobilized metal ion affinity membrane could be applied for the large-scale isolation of papain without resulting in enzyme denaturation.     

壳聚糖超滤膜的制备及在低含量重金属废水处理中的应用

报道了壳聚糖超滤膜的制备及主要性能,确定了壳聚糖溶液成膜的最佳条件,制备的超滤膜透水速度为3～4mL cm2·h,对0.1%牛血清蛋白溶液的截留率可达90%。用此膜对低含量重金属废水进行处理,结果表明:通过调节溶液的pH值,使重金属离子在水溶液中形成胶体,用壳聚糖超滤膜可有效地去除水中Pb2+、Cd2+、Zn2+、Cu2+等金属离子的氢氧化物。     

小球藻吸附水体中Cd~(2+)、Pb~(2+)和Cu~(2+)的试验研究

为了研究小球藻藻体吸附水体中Cd2+、Pb2+和Cu2+的情况,在检测了典型电子垃圾处理区水体中重金属Cd、Pb和Cu浓度的基础上,采用冷冻干燥的小球藻藻体在模拟重金属离子溶液中进行吸附试验。结果表明,水体中重金属Cu的浓度较高,Cd和Pb的污染程度较严重。藻体对于Pb2+的去除效果较好,去除率和去除量分别达到88.42%和13.262 4 mg/g;Cu2+的去除率较低,但去除量高达17.480 6 mg/g;Cd2+去除率较高,但去除量仅有0.433 7 mg/g。