三乙二醇二甲基丙烯酸酯为交联剂制备的高吸水树脂对重金属的吸附

以前期工作中合成的树脂PAANa-TE为吸附剂进行重金属吸附测试,考察吸附剂用量、丙烯酸中和度、吸附时间、溶液pH、初始浓度和吸附温度对树脂吸附重金属离子Cu2+、Pb2+、Cr3+和Co2+性能的影响,用原子吸收分光光度计测定了树脂吸附Cu2+、Pb2+、Cr3+和Co2+后的残留浓度,树脂对4种金属离子的吸附容量分别为21.59、2.39、5.66和4.98 mmol/g,吸附容量大小为Cu2+Cr3+Co2+Pb2+,吸附速率顺序为Cr3+Pb2+Cu2+Co2+。结果表明,该树脂对高浓度重金属离子有较快速,高效率的吸附,吸附过程在100 min左右吸附容量达到最大,并用不同浓度的酸对吸附重金属离子的树脂进行脱附处理,脱附量很小,据此可考虑进一步对金属离子进行回收处理。且脱附率较低,因此,可对工业化和城市化进程所产生的各种化学形态的重金属水体污染物造成的生态环境和质量问题起到重要的改善作用。     

4A沸石对复合污染水体中Pb2+、Cu2+和Cd2+的去除

采用静态吸附法以4A沸石为吸附剂研究其对复合污染水体中Pb2+、Cu2+和Cd2+的竞争吸附特性,并探讨了影响吸附的环境因素。实验表明,在室温条件下,溶液pH5～6,4A沸石15 mg对10 mL复合污染溶液(Pb2+、Cu2+和Cd2+浓度分别为100 mg/L)吸附20 min时,对溶液中3种重金属的吸附去除率均可达99.8%以上。反应过程中4A沸石对3种重金属的吸附速率大小为Pb2+>Cu2+>Cd2+。复合污染水体中4A沸石对Pb2+、Cu2+和Cd2+的吸附符合Langmuir和Fre-undlich等温吸附方程,相关系数分别为0.9981、0.9901、0.9916和0.9638、0.9194、0.9689。经计算,4A沸石对Pb2+、Cu2+和Cd2+的饱和吸附量分别为129.9 mg/g、107.5 mg/g和99.0 mg/g。4A沸石吸附重金属离子达到吸附平衡的时间较短,对溶液pH值的适应性较好。吸附后的4A沸石可以再生利用,对铅离子洗脱重复利用性较铜离子和镉离子强。     

骨炭对Pb(Ⅱ)的吸附特性

通过间歇实验研究了骨炭对重金属Pb(Ⅱ)的吸附特性。探讨了固液比、pH、离子强度、反应时间、温度及初始浓度等因素的影响。实验结果表明,pH与固液比显著影响去除率,温度与离子强度的影响较小。当温度为20℃,pH=2.5,Pb(Ⅱ)的初始浓度为200 mg/L,固液比为1 g/L时,最大去除率近100%。动力学实验结果表明,骨炭对Pb(Ⅱ)的吸附为快速反应,在30 min内可达到平衡,准二级动力学模型可较好地拟合实验结果。等温吸附实验结果表明,Freundlich模型与Langmuir模型均可较好地拟合等温吸附实验结果。骨炭对Pb(Ⅱ)的吸附机制主要为表面络合反应与分解置换-沉淀反应。     

沸石负载淀粉对Pb2+、Cu2+和Ni2+的吸附性能

将淀粉负载到沸石表面得到新型重金属离子复合吸附剂ZLS。分别从沸石与淀粉质量比、吸附温度、吸附时间、pH与重金属初始浓度不同方面考察了复合吸附剂ZLS吸附 Pb²⁺、Cu²⁺、Ni²⁺的影响。实验结果表明:当沸石与淀粉质量比为10:1,pH为6,吸附温度在30℃时,复合型吸附剂ZLS对Pb²⁺、Cu²⁺和Ni²⁺ 3种重金属离子的吸附效果最好;吸附动力学研究发现,ZLS对Pb²⁺、Cu²⁺和Ni²⁺的吸附行为均符合准二级动力学以及颗粒内部扩散模型;等温吸附数据符合Freundlich模型,吸附状态属于多层吸附。     

沸石负载淀粉对Pb2＋、Cu2＋和Ni2＋的吸附性能

将淀粉负载到沸石表面得到新型重金属离子复合吸附剂ZLS。分别从沸石与淀粉质量比、吸附温度、吸附时间、pH与重金属初始浓度不同方面考察了复合吸附剂ZLS吸附Pb^2＋、Cu^2＋、Ni^2＋的影响。实验结果表明：当沸石与淀粉质量比为10：1，pH为6，吸附温度在30℃时，复合型吸附剂ZLS对Pb^2＋、Cu^2＋和Ni^2＋3种重金属离子的吸附效果最好；吸附动力学研究发现，ZLS对Pb^2＋、Cu^2＋和Ni^2＋的吸附行为均符合准二级动力学以及颗粒内部扩散模型；等温吸附数据符合Fre-undlich模型，吸附状态属于多层吸附。     

酵母菌对不同液相体系中锌离子的吸附行为

主要对面包酵母菌在Zn2+和Zn2+-Pb2+两种离子体系中Zn2+的吸附行为进行了探讨。选择灭活面包酵母菌为吸附剂,对pH、菌体加入量等吸附影响因素进行了探讨并进行了吸附动力学过程和等温吸附效果的研究。结果表明,不同离子体系中相同初始浓度情况下,动力学研究显示实验所用面包酵母菌对溶液中Zn2+而言是一种快速高效的生物吸附剂,且在整个吸附过程中存在:qt(Pb2+)qt(Zn2+-Pb2+)qt(Zn2+)。实验条件下,以单离子体系中的Zn2+、Pb2+和双离子体系中的总离子为研究对象时,都能很好符合Langmuir等温吸附模型,计算获得面包酵母菌对不同离子体系的最大吸附量大小顺序为:qmax(Zn2+-Pb2+)qmax(Zn2+)qmax(Pb2+);然而通过对动力学吸附过程、实际平衡吸附量qeqex、吸附能力参数KL和EDS测试结果的综合分析,认为面包酵母菌对各体系中离子的吸附能力大小顺序为:Pb2(单+)(Zn2+-Pb2+)Zn(2单+)。同时认为Pb2+的存在对面包酵母菌吸附Zn2+的行为过程具有强烈抑制作用。     

皂化改性橘子皮生物吸附剂对重金属离子的吸附

以生物废料橘子皮(OP)为原料,经乙醇、氢氧化钠处理,得到改性橘子皮生物吸附剂SOP,将其用于对重金属离子Cu2+、Pb2+、Cd2+、Zn2+和Ni2+的吸附。研究了溶液pH、吸附时间和重金属离子初始浓度对SOP吸附性能的影响。结果表明,重金属离子在生物吸附剂上的吸附速率快,符合准二级动力学方程。SOP对重金属离子的吸附等温线符合Lang-muir模型,根据Langmuir模型计算SOP对Cu2+、Pb2+、Cd2+、Zn2+和Ni2+的饱和吸附量分别为56.82、152.4、66.27、33.90和23.02 mg/g,均高于改性前。常见阳离子的存在对重金属离子吸附的影响较小,改性后的橘子皮生物吸附剂可以再生重复使用4次以上,是性能良好的重金属离子吸附剂。     

柿粉树脂的制备及其吸附Cu2+和Pb2+的效应

以柿粉为原料通过甲醛交联固化制备出柿粉树脂(PPR);利用傅里叶红外光谱(FT-IR)、Zeta电位、热变性温度、比表面积等对其进行表征,并探讨其吸附Cu2+和Pb2+的效应。结果表明,(1)PPR对Cu2+和Pb2+的吸附效果显著高于柿粉与活性炭;(2)p H值对吸附平衡影响较大,最佳p H值范围为5.0~6.0;(3)PPR对Cu2+和Pb2+的吸附在180 min内可达到吸附平衡,提高吸附温度可提高吸附速率,其吸附动力学数据可用拟二级速率方程良好拟合;(4)提高金属离子初始浓度可增加平衡吸附量,Freundlich和Langmuir方程可分别拟合PPR对Cu2+(R2>0.98)和Pb2+(R2>0.99)的吸附等温线;(5)PPR(2.0 g/L)可吸附混合重金属溶液中83.73%的Cu2+和98.63%的Pb2+;(6)PPR可循环使用5次以上;(7)PPR对Cu2+与Pb2+的吸附效应可能是静电吸附与配位反应共同作用的结果。该研究结果表明,PPR是一种有应用前景的处理含重金属废水的备选材料。     

改性玉米淀粉对Cu~(2+)、Pb~(2+)和Zn~(2+)的吸附特性研究

以玉米淀粉为原料,经过交联、醚化、胺化和亲核加成等步骤合成了一种新型重金属吸附剂——二硫代氨基甲酸改性淀粉(DTCS)。改性淀粉的结构采用红外光谱和扫描电镜进行表征。DTCS是一种性能优良的重金属吸附剂,对Cu2+、Pb2+和Zn2+的饱和吸附容量随着pH(pH=2~6)的增加而增大。在有EDTA络合剂存在和酸性废水pH小于3的情况下,DTCS对Cu2+、Pb2+和Zn2+仍有较高的去除率,分别达到90%、75%和50%以上,说明DTCS在含重金属离子的实际废水体系具有一定的实用价值。     

黑土胶体对铅的吸附动力学特征

利用虹吸法从采自于吉林省黑土中分别提取出粒级为5~10、2~5和1~2μm的3种胶体,并通过批次实验法研究不同粒级黑土胶体对Pb2+的吸附动力学。结果表明,不同粒级土壤胶体对Pb2+的吸附过程均表现为快慢2个阶段,其中,10 min内呈现快速吸附阶段,之后为慢速吸附阶段。3种粒级土壤胶体5~10、2~5和1~2μm在pH为6、温度为25℃时,对Pb2+的饱和吸附量为114.45、126.98和131.89 mmol/kg。随pH从2升到6,粒级为5~10、2~5和1~2μm的3种胶体对Pb2+的饱和吸附量分别增加了928%、153%和142%。随温度从25℃升到55℃,粒级为5~10、2~5和1~2μm的3种胶体对Pb2+的饱和吸附量分别增加了16.56%、4.9%和4.89%。不同粒级胶体对Pb2+的吸附量由大到小依次为:1~2μm2~5μm5~10μm。不同粒级胶体对Pb2+的吸附动力学均较好地符合拉格朗日准二级动力学方程,说明该吸附过程以化学吸附为主。准二级动力学吸附速率常数表明,随着吸附剂粒径增大,吸附速率降低。4种温度范围内随着温度升高,吸附速率加快。吸附过程的限速步骤为颗粒间扩散。     

浮游球衣菌对Pb2+、Cu2+、Zn2+、Cd2+的吸附性能研究

研究了浮游球衣菌（Sphaerotilus natans）在不同吸附条件下对溶液中Pb^2＋、Cu^2＋、Zn^2＋、Cd^2＋的吸附规律。结果表明,Sphaerotilus natans对这4种重金属离子均有一定的吸附作用,并在20min内达到吸附平衡,pH对吸附过程影响较大,pH为5.5时Sphaerotilus natans对这4种金属离子的吸附效果最好,Sphaerotilus natans对它们的吸附选择性为Pb^2＋〉Cu^2＋〉Zn^2＋〉Cd^2＋,Pb^2＋、Cu^2＋能部分置换出已被菌体吸附的Zn^2＋、Cd^2＋。HCI和EDTA溶液可有效地将金属离子从菌体上解吸下来,解吸后的菌体可重复使用。     

重金属离子在腐植酸上吸附的研究

对4种代表性重金属离子在腐植酸上吸附、pH对竞争吸附的影响及其吸附机理进行了研究。结果表明，Cu2＋、Pb2＋、Zn2＋的吸附等温线为F型，而Cd2＋等温线为L型；2．5＜pH＜3．5时，竞争吸咐次序为Cu2＋＞Pb2＋＞Cd2＋＞Zn2＋；pH＞5．0时，Cd2＋＞Cu2＋＞Zn2＋＞Pb2＋；Cu2＋在腐植酸上的吸附主要是以与腐植酸形成配合物的方式相互结合。     

Evaluation of pectin binding of heavy metal ions in aqueous solutions

Evaluation of adsorption performance of several industrially manufactured pectins towards some toxic heavy metals was carried out. Adsorption isotherms for divalent cations in simulant aqueous solutions were measured and corresponding distribution coefficients were calculated. The following selectivity sequences we found for pectins: Pb2+ > Cu2+ > Co2+ > Ni2+ > Zn2+ > Cd2+. It was shown that a beet pectin exhibits a high affinity for Pb2+ and Cu2+ ions, an apple pectin for Co2+ ion and a citrus pectin for Ni2+ ion. The binding properties of all pectins towards Zn2+ and Cd2+ ions are extremely poor. The quantitative data on adsorption performance of pectins suggest their applicability as food additives or remedies for efficient removal of Pb2+, Cu2+, Co2+, and Ni2+ ions from different biological systems, including human and animal organisms.     

Influence of metal ion on sorption of p-nitrophenol onto sediment in the presence of cetylpyridinium chloride

Heavy metals and surfactants have a significant effect on the sorption of organic contaminants. In this study, batch equilibrium experiments were carried out to investigate the influence of Pb(NO(3))(2) on the sorption of p-nitrophenol (PNP) onto sediments in the presence of cationic surfactant cetylpyridinium chloride (CPC). Results indicated that in the complex system containing PNP, Pb(NO(3))(2) and CPC, the sorption of PNP decreased with increasing concentration of Pb(NO(3))(2) due primarily to competing for adsorption sites. Likewise, partitioning of PNP in adsorbed surfactant layers and micelles decreased with increasing level of Pb(NO(3))(2). Moreover, the influence of different metal ions (Pb(2+), Cd(2+), Zn(2+)) was examined and results indicated that the presence of heavy metals inhibited the sorption of PNP in the order: Pb(2+)>Cd(2+)>Zn(2+). The competitive effect of the heavy metals was in agreement with the hydration energy and hydrated radius. The results are believed to provide a useful insight into describing the transport and fate of PNP in natural environments.     

表面活性剂对多壁碳纳米管吸附Pb~(2+)的影响

多壁碳纳米管(MWNT)在吸附有毒气体和重金属离子方面具有极高的应用价值.针对MWNT对水溶液中Pb2+的净化吸附进行了研究,从吸附量,吸附速率、动力学角度考察了表面活性剂、Pb2+浓度对MWNT吸附Pb2+的影响.结果表明,司班-60、吐温-20、阿拉伯树胶等表面活性剂的加入,促进了MWNT在溶液中的分散,导致在Pb2+摩尔浓度为3～18 mmol/L的Lang-muir和Freundlich等温吸附方程中的吸附常数(K)变大,使得MWNT对Pb2+的吸附速率和平衡吸附量都得到提高;随着溶液中Pb2+浓度的增大,MWNT对其吸附量渐至饱和,随后由于Pb2+的位阻作用.吸附量下降;在这3种表面活性剂中,由于司班-60具有相对较小的分子量,其分散的MWNT在Pb2+摩尔浓度为14 mmol/L时,吸附量最大,为230 mg/g.     

Simultaneous heavy metal removal mechanism by dead macrophytes

The use of dead, dried aquatic plants, for water removal of metals derived from industrial activities as a simple biosorbent material has been increasing in the last years. The mechanism of simultaneous metal removal (Cd2+, Ni2+, Cu2+, Zn2+ and Pb2+) by 3 macrophytes biomass (Spirodela intermedia, Lemna minor and Pistia stratiotes) was investigated. L. minor biomass presented the highest mean removal percentage and P. stratiotes the lowest for all metals tested. Pb2+ and Cd2+ were more efficiently removed by the three of them. The simultaneous metal sorption data were analysed according to Langmuir and Freundlich isotherms. Data fitted the Langmuir model only for Ni and Cd, but Freundlich isotherm for all metals tested, as it was expected. The K(F) values showed that Pb was the metal more efficiently removed from water solution. The adsorption process for the three species studied followed first order kinetics. The mechanism involved in biosorption resulted ion exchange between monovalent metals as counter ions present in the macrophytes biomass and heavy metal ions and protons taken up from water. No significant differences were observed in the metal exchange amounts while using multi-metal or individual metal solutions.     

Response of kidney bean to concentration and chemical form of cadmium, zinc, and lead in polluted soils

Seven soils which had been polluted with heavy metals from a zinc smelter were sequentially extracted so that Cd, Zn, and Pb could be partitioned into five operationally defined geochemical fractions: exchangeable, carbonate, Fe-Mn oxide, organic, and residual fractions. Kidney beans were planted in the soils to examine the effect of concentration and chemical form of the metals in soil on the growth and metal uptake of the plants. The growth of kidney bean was restricted in heavy metal polluted soils compared with controls. Metal concentration and metal uptake by plants were correlated. The highest relationship was found between amount of metal uptake and the metal concentration in exchangeable + carbonate forms. The uptake of metals was according to their solubility sequence, i.e. Cd > Zn > Pb. The uptake rate of exchangeable + carbonate forms was the same for the three elements.     

Multi-component adsorption of copper,nickel and zinc from aqueous solutions onto activated carbon prepared from date stones

The removal of Cu²⁺, Ni²⁺, and Zn²⁺ ions from their multi-component aqueous mixture by sorption on activated carbon prepared from date stones was investigated. In the batch tests, experimental parameters were studied, including solution pH, contact time, initial metal ions concentration, and temperature. Adsorption efficiency of the heavy metals was pH-dependent and the maximum adsorption was found to occur at around 5.5 for Cu, Zn, and Ni. The maximum sorption capacities calculated by applying the Langmuir isotherm were 18.68 mg/g for Cu, 16.12 mg/g for Ni, and 12.19 mg/g for Zn. The competitive adsorption studies showed that the adsorption affinity order of the three heavy metals was Cu²⁺?>?Ni²⁺?>?Zn²⁺. The test results using real wastewater indicated that the prepared activated carbon could be used as a cheap adsorbent for the removal of heavy metals in aqueous solutions.     

The capture of heavy metals from incineration using a spray dryer integrated with a fabric filter using various additives

This study investigated the effects of feedstock additives [polyvinyl chloride (PVC) and NaCl] and spray dryer additives (SiO2, CaCl2, NaHCO3) on heavy metal and fly ash removal efficiencies, and on particle size distribution of heavy metals. A spray dryer with an integrated fabric filter was used as an air pollution control device (APCD). Removal efficiencies for fly ash and heavy metals were greater than 95 and 90%, respectively. When additives of PVC or NaCl were used, the concentration of heavy metals distributed in fly ash apparently varied when the particle diameter was <1 microm. Although the effects of the additives SiO2, CaCl2, and NaHCO3 on the elemental size distribution of Cr were insignificant, these additives did slightly increase concentrations of Cd, Zn, and Pb partitioning in coarser particles (>1 microm).