重金属离子天然吸附剂的解吸与再生

总结了重金属离子的天然吸附剂的解吸与再生的研究进展.着重论述了各类解吸剂的解吸原理、解吸特点和解吸性能.指出无机酸解吸剂是价廉高效的理想解吸剂,其中盐酸可在低浓度下达到较高的解吸率,且对吸附剂性能没有损害,而强碱溶液是以阴离子基团形式存在的Cr~(6+)的专有解吸剂.在解吸过程中采用超声波或微波有助于提高解吸率.多数天然吸附剂都具有良好的再生能力,经5次吸附-解吸循环操作仍能保持原有的吸附性能.     

重金属吸附剂壳聚糖的改性研究进展

综述了重金属吸附剂壳聚糖改性研究的新进展,介绍了交联与接枝等改性方式对壳聚糖稳定性的影响及改性后的壳聚糖对水体中重金属离子吸附性能的改善.针对壳聚糖改性中仍然存在的一些问题,指出今后研究中值得关注的方向.     

壳聚糖吸附重金属离子的研究进展

综述了,我国近几年来壳聚糖处理含重金属离子废水的研究进展。壳聚糖及其改性产品的吸附性能主要体现在对各种金属离子的吸附上,为了有选择性地吸附某种或某些金属离子,人们通过修饰、交联、接枝等方法对壳聚糖进行了各种改性研究。     

壳聚糖改性凹凸棒土对重金属离子的吸附

采用浸渍法将壳聚糖负载在凹凸棒土上,制备了改性的凹凸棒土。用该吸附剂吸附溶液中Pb^2＋,Cd^2＋的实验结果表明：未负载壳聚糖时,凹凸棒土对Cd^2＋的吸附率为55%;当负载壳聚糖的质量分数为0.04时,凹凸棒土对Cd^2＋的吸附率达最大值（为91%）,对Pb2＋的吸附率也达最大值（为75%）。其吸附行为符合Langmuir等温吸附方程和Freundlich等温吸附方程。该吸附剂可重复使用。     

土壤聚合物的制备及其固化重金属离子的研究

土壤聚合物(土聚物)是一种新型的无机聚合物,其分子链由Si,O,Al等以共价键连接而成,是具有网络结构的类沸石,对重金属有较强的固定作用。初步探索了用偏高岭土、碱激活剂等合成土聚物的工艺条件,研究了原料配方、水的加入量对土聚物性能的影响。当氧化硅与氧化铝的摩尔比为4．0-4.5、氧化钠与氧化硅的摩尔比为0．27—0．35时,得到了抗压强度大于48MPa的土聚物;用其固化Zn^2 ,Pb^2 ,Cu^2 和Cd^2 ,其对上述重金属离子的捕集效率为96．86％,99．86％。     

污泥中重金属离子的电动力学去除技术

概述了国内外电动力学去除技术的研究现状以及污泥中重金属离子的存在形态、水解引起的pH变化、电极极化、外加酸和螯合剂、电流和电压等对该技术的影响。阐明了利用电动力学去除技术去除剩余污泥中重金属离子的可行性。指出了今后电动力学去除技术重点研究的方向。     

污泥-谷壳吸附剂对混合染料吸附机理的研究

污泥和谷壳为原料制备了污泥-谷壳吸附剂（SCA）。采用SCA处理酸性大红和碱性嫩黄模拟混合染料废水。通过动力学分析、FTIR表征和SEM表征对SCA吸附混合染料的机理进行了研究。实验结果表明：在吸附温度25 ℃、混合溶液中酸性大红和碱性嫩黄的质量浓度均为100 mg/L、SCA加入量0.5 g/L、吸附时间400 min的条件下,酸性大红的吸附量为125 mg/g,碱性嫩黄的吸附量为170 mg/g;SCA对混合染料的吸附行为符合拟二级反应动力学方程,液膜扩散为吸附的主要控制过程。表征结果显示：SCA孔隙发达且丰富,以中孔和细密的微孔为主,说明SCA具有较高的吸附能力; SCA中包含C—H,C—OH,C—C,CC等主要官能团,SCA对混合染料的吸附为物理吸附。     

交联壳聚糖季铵盐吸附剂的制备及其对重金属离子的吸附

以壳聚糖为原料、二甲基二烯丙基氯化铵（DMDAAC）为接枝单体、甲醛为预交联剂、环氧氯丙烷为交联剂,通过反相乳液聚合制备出交联壳聚糖季铵盐吸附剂,并将其用于吸附Ni（Ⅱ）和Cr（Ⅵ）。考察了吸附时间、溶液初始浓度、溶液pH等因素对吸附效果的影响。实验结果表明：该吸附剂对Ni（Ⅱ）和Cr（Ⅵ）的吸附过程遵循拟二级动力学方程,吸附等温线符合Langmuir方程;在30 ℃条件下,Ni（Ⅱ）和Cr（Ⅵ）的溶液初始浓度均为1 mmol/L时,该吸附剂吸附Ni（Ⅱ）和Cr（Ⅵ）的最佳溶液pH分别为7和6,对应的平衡吸附量分别为1.18,1.99 mmol/g;该吸附剂可用盐酸再生,重复使用性能良好。     

交联阳离子淀粉的合成及其对重金属离子的吸附

通过正交实验合成了取代度为0．568的交联阳离子淀粉。考察了溶液pH、螯合剂用量、重金属离子初始浓度对交联阳离子淀粉去除重金属离子效果的影响。当重金属离子初始质量浓度为50mg／L、螯合剂投加量为0．5g／U时,Pb^2 ,Cu^2 ,Cr^3 在溶液pH为6时的去除率达到最高,分别为97．94％,99．46％,84．30％,而Cd^ 在溶液pH为7时的去除率达到最高,为99．36％。实验结果表明,交联阳离子淀粉是一种有效去除废水中重金属的处理剂。     

水合肼改性淀粉去除废水中的重金属离子

以木薯淀粉为原料、硝酸铈铵为引发剂,合成丙烯酸甲酯接枝淀粉;用水合肼对其进行改性,合成了具有氨基功能团的改性淀粉。将改性淀粉用于对多种单一重金属离子和混合重金属离子的去除。在混合重金属离子溶液中,在室温、改性淀粉加入量为7.0g/L、重金属离子质量浓度为30mg/L、反应时间为120min的条件下,混合液pH为3～7时,改性淀粉对Cu2+、Pb2+、Cd2+和Ni2+的去除率均达99.9%以上;混合液pH为4时,改性淀粉对Cr6+的去除率达73.2%。     

Study on Synthesis of Comb-Shaped Chitosan-Graft-Polyethylenimine Dithiocarbamate Material and Its Adsorption to Heavy Metal Ions

Journal of Polymers and the Environment - How to efficiently and economically remove heavy metals from sewage has been a huge challenge in the world. This article reports on an adsorbing material...     

常温铁氧体法处理重金属离子废水研究

以Ca（OH）2饱和溶液作pH调整剂,以N％CO2作添加剂,采用常温铁氧体法处理重金属离子废水。研究了重金属离子类型及n（Fe^2＋）／n（M^2＋）对磁性产物性质的影响：实验结果表明：重金属离子类型及（Fe^2＋）／n（M^2＋）对磁性产物中金属的回收率、磁性产物的稳定性及饱和磁化率均有较大的影响。采用该法处理金属采选废水,处理后的废水中各种金属离子的质量浓度均达到污水综合排放标准（GB8978-1996）。     

聚丙烯酰-6-氨基吡啶的制备及其对重金属离子的吸附

以2,6-二氨基吡啶为原料,合成了功能单体2-丙烯酰-6-氨基吡啶,并将其与乙二醇二甲基丙烯酸酯共聚合成了聚合物吸附剂聚丙烯酰-6-氨基吡啶。考察了聚合物吸附剂对重金属离子的吸附分离性能。实验结果表明：在混合液中Cu²⁺,Zn²⁺,Cd²⁺,Ni²⁺的初始质量浓度均为10 mg/L、聚合物吸附剂加入量为5 g/L、溶液pH=7、吸附时间为10 min的条件下,聚合物吸附剂对各离子的吸附率均大于90%;采用浓度为0.5 mol/L的HCl溶液对吸附后的聚合物吸附剂进行洗脱,4种重金属离子的洗脱率均可达97%以上;该吸附剂具有很好的稳定性,重复使用11次后其对4种重金属离子的饱和吸附量均未有明显的下降。     

Extraction of Lignosulfonate from Black Liquor into Construction of a Magnetic Lignosulfonate-Based Adsorbent and Its Adsorption Properties for Dyes from Aqueous Solutions

Journal of Polymers and the Environment - Lignosulfonate, one of the lignin derivatives, was extracted from the black liquor as a byproduct of the wood and paper industry. It was used to prepare...     

交联壳聚糖/沸石复合吸附剂的制备及性能

用沸石负载由缩水甘油基三乙基氯化铵交联的壳聚糖,制得了性能良好的交联壳聚糖/沸石复合吸附剂。研究了该吸附剂应用性能的影响因素,探讨了该吸附剂的吸附性、沉降性和重复使用性,利用FTIR仪和高倍透射电子显微镜对该吸附剂的结构进行了表征。实验结果表明:壳聚糖的交联度为0.93、交联壳聚糖与沸石的质量比为0.045时,制得的交联壳聚糖/沸石复合吸附剂对腐殖酸的去除率可达81.4%,吸附量为4.07mg/g;交联壳聚糖/沸石复合吸附剂对腐殖酸的吸附性能较沸石有显著提高,沉降时间较交联壳聚糖明显缩短;经二次洗脱后腐殖酸去除率仍可达80.2%,腐殖酸吸附量为4.01mg/g。     

用粉煤灰吸附废水中的金属离子

研究了在粉煤灰对金属离子的吸附反应中溶液pH及共存离子对金属离子去除率的影响,分析了粉煤灰对金属离子的吸附动力学,并考察了粉煤灰对实际废水的处理效果。实验结果表明,随pH的增大,金属离子的去除率增大。吸附等温线符合Fretmdlich模型,但在pH为4．5时表现为单一线性段、在pH为6时表现为两个线性段。粉煤灰对金属离子的吸附明显受到其他共存离子的影响。对钢铁厂生产废水的吸附实验结果表明,在pH为8、粉煤灰加入量为20g/L时,废水中Cd^2＋,Cu^2＋,Pb^2＋,Zn^2＋的去除率分别为70％,100％,100％,100％。     

Effects of Decreased Atmospheric Heavy Metal Deposition in South Sweden on Terrestrial Birds and Small Mammals in Natural Populations

In southern Sweden, where exposure to long range distributedheavy metals is about the highest in Scandinavia, depositionsof cadmium (Cd) and lead (Pb) decreased about 20 and 70%,respectively, between mid-1980s and mid-1990s, as estimated bytheir concentrations in moss. Concentrations of Cd and Pb in tissues of the pied flycatcher (Ficedula hypoleuca) and bank vole (Clethrionomys glareolus) were also lower in 1996and 1997 compared to 1981 and 1982. It is concluded that the decreased deposition rate of these elements in southern Sweden had caused decreased exposure, and thus also to decreased potential risk of detrimental effects on insectivorous birds andherbivorous mammals. There was no indication that breeding results of pied flycatcher was influenced by the decreased deposition of toxic metals.     

Preparation of Natural Composite Microcapsules Containing Orchid Black Currant Fragrance and its Sustained-Release Properties on Hair Bundle

Journal of Polymers and the Environment - In this paper, we developed an environmentally friendly microcapsules with natural materials to replace plastic microbeads used in personal care products...     

The Effect of Nanoclays on the Properties of PLLA-modified Polymers Part 1: Mechanical and Thermal Properties

Organically modified montmorillonite clays were incorporated at a 5% loading level into film grade of poly-L-lactic acid (PLLA) using a variety of masterbatches based on either semi-crystalline or amorphous poly-(lactic acid), as well as biodegradable aromatic aliphatic polyester. The PLLA masterbatches and compounded formulations were prepared using a twin screw compounding extruder, while the films were prepared using a single screw cast film extruder. The thermal and mechanical properties of the films were examined in order to determine the effect of the clay and different carriers on the polymer–clay interactions. In the optimal case, when a PLLA-based masterbatch was used, the tensile modulus increased by 30%, elongation increased by 40%, and the cold crystallization temperature decreased by 15 °C, compared to neat PLLA. The properties improvement of PLLA films containing nano clays demonstrated the possibility to extend the range of biodegradable film applications, especially in the field of packaging.     

Converting Waste Polystyrene into Adsorbent: Potential Use in the Removal of Lead and Cadmium Ions from Aqueous Solution

Waste of polystyrene was converted into a cation exchange resin and was used for the removal of lead and cadmium metals from aqueous solution. Wastes consisting of coffee cups were crushed into small pieces and immersed into a solution of sulfuric acid in order to attach sulfonic group to polymer chain, these groups are responsible for the exchange properties of the modified plastic. The cation exchange capacity (CEC) was determined and was comparable to commercial exchangers. The adsorption isotherms of resin with synthetic wastewater containing lead and cadmium ions were tested. Adsorption analysis results obtained at various concentrations showed that the adsorption pattern on the resin followed Langmuir isotherms.