化肥对聚丙烯酸高吸水性树脂吸液性能的影响

以自制的聚丙烯酸高吸水性树脂（PAAS）研究了化肥对其吸液性能的影响。结果表明，PAAS在蒸馏水、0．9％NaCl溶液中的吸液倍率分别为：550、59g／g，在蒸馏水中吸水倍率随所吸溶液温度升高而下降，而在0．9％NaCl溶液中吸液倍率则随所吸溶液温度增加而增加；在蒸馏水和0．9％NaCl溶液中对不同PAAS，吸液倍率随聚合反应温度升高先增大后减小；对同一种化肥溶液，PAAS树脂的吸液倍率随化肥溶液浓度增加而减小；化肥溶液浓度相同时，吸液倍率顺序为尿素〉〉硝酸铵〉磷酸二氢钠〉硝酸钾〉磷酸氢二钠、磷酸铵〉磷酸钾。在相同浓度的化肥K3PO4溶液中，吸液倍率随聚合反应温度增加而下降。     

PAMPS高吸水性树脂吸附性能

用溶液聚合法合成了聚(2-丙烯酰胺-2-甲基丙磺酸)高吸水性树脂(PAMPS树脂),研究了树脂在Pb(NO3)2、Cu(NO3)2、Zn(NO3)2溶液中的吸附性能,结果表明,在单一金属离子溶液中,实验范围内PAMPS树脂吸附量随溶液浓度增加而增大,对Pb2 的吸附量还随交联剂浓度和单体中和度增加而增大;在二元和三元混合金属离子溶液中,PAMPS树脂对Pb2 有很好的选择吸附性。     

羽毛蛋白接枝丙烯酸-丙烯酰胺高吸水性树脂的吸附性能

通过水溶液聚合法合成了羽毛蛋白接枝丙烯酸-丙烯酰胺高吸水树脂,即FP-P(AA-AM)。研究了树脂在单一Cd2+溶液中的吸附行为以及在Cd2+、Cu2+、Zn2+三元混合溶液中的选择性吸附性能。结果表明,在单一Cd2+溶液中,FP-P(AA-AM)树脂对Cd2+的吸附容量随硫酸镉溶液浓度的增大而增大,最高可达2.4mmol/g。吸附Cd2+至饱和的树脂能在1mol/L的HCl溶液中很好的进行解吸附,3min时解吸附率即可达到83.3%。在较高浓度的三元金属离子混合溶液中,FP-P(AA-AM)树脂对3种离子呈现出一定的选择性吸附,其平衡吸附量顺序为:Cu2+Cd2+Zn2+。     

多氨基改性蔗渣对水溶液中Pb~(2+)、Zn~(2+)、Cd~(2+)、Cu~(2+)吸附性能的研究

蔗渣经多氨基改性处理后,得到多氨基改性蔗渣吸附剂。考察了多氨基改性蔗渣吸附剂对模拟废水中Pb2+、Zn2+、Cd2+、Cu2+的吸附性能,主要包括吸附时间、溶液pH值和温度对吸附量的影响以及吸附等温式的研究。研究表明,在实验范围内,Pb2+的吸附平衡时间为12h,适宜吸附Pb2+的pH值范围在4～5,Pb2+的最大吸附量为34.96mg/g;Zn2+的吸附平衡时间为20h,适宜吸附Zn2+的pH值在6.2左右,Zn2+的最大吸附容量为2.24mg/g;Cd2+的吸附平衡时间为20h,适宜吸附Cd2+的pH值在5.0左右,Cd2+的最大吸附容量为10.40mg/g;Cu2+的吸附平衡时间为20h;适宜吸附Cu2+的pH值在5.0左右;Cu2+在不同温度下的最大吸附容量为2.60mg/g。多氨基改性蔗渣对Pb2+、Zn2+、Cd2+、Cu2+的吸附均可用Freundlich方程和Langmuir方程描述。     

胶团强化超滤中SDS胶团对Cd^2＋，Zn^2＋和Pb^2＋的竞争吸附

胶团强化超滤法是一种将表面活性剂技术和超滤技术结合的新型、高效的重金属废水治理方法.以十二烷基硫酸钠(SDS)为表面活性剂,对含单一镉、锌、铅溶质以及混合溶质体系进行了胶团强化超滤研究,考察了胶团对Cd2 ,Zn2 ,Pb2 的竞争吸附性能.研究发现,当溶液中多种二价重金属离子存在时,各离子之间存在与SDS胶团的竞争吸附,竞争能力为Pb2 ＞Zn2 ＞Cd2 ;Cd-Zn有明显的协同吸附效应,而Cd-Pb,Zn-Pb则表现为拮抗吸附.     

KLPAAM复合高吸水性树脂吸液性能研究

以自制高岭土/木质素磺酸钠接枝丙烯酸-丙烯酰胺复合高吸水性树脂(KLPAAM)为原料,考察了其在含氮、磷、钾的不同离子盐溶液中的吸液性能.(1)质量浓度相同时,KLPAAM树脂在K<'+>盐溶液中的平衡吸液倍率顺序:KFCO<,3><(K<,3>PO<,4>;在NH<,4><'+>盐溶液中的平衡吸液倍率顺序:NH<,4>NO<,3><(NH<,4>)<,2>CO<,3><(NH<,4>)<,3>PO<,4>HCO<,3>.相同阴离子的K<'+>盐溶液和NH<,4><'+>盐溶液中平衡吸液倍率较为接近;在30min之前,KLPAAM树脂的吸液倍率急剧增加,50min左右时吸液倍率达最大值,50min至100min吸液倍率稍有下降,之后达平衡.(2)在氮、磷、钾盐溶液中,KLPAAM树脂的平衡吸液倍率与溶液浓度的关系满足Q=k×(1/c)<'n>方程,而吸液前60min的吸液速率可用方程t/Q＝A+Bt进行拟合,其相关系数大于0.99.     

聚乙烯亚胺-羧甲基纤维素的合成及对金属离子的吸附性能

以羧甲基纤维素(CMC)为基质,用戊二醛(GA)做交联剂,将聚乙烯亚胺(PEI)交联到羧甲基纤维素上制得聚乙烯亚胺-羧甲基纤维素吸附剂(PEI-CMC)。采用傅里叶变换红外光谱、扫描电镜、X射线光电子能谱对PEI-CMC的结构进行了表征,测定了其对Cu2+、Pb2+和Cd2+的吸附性能,并研究了pH值、时间、金属离子的初始浓度对吸附的影响。结果表明,当CMC、PEI和GA的反应比为1 g∶5 mL∶20 mL,反应温度为25℃,反应时间为3 h时,合成的PEI-CMC的含氮量为13.23%。当CMC和PEI的反应比为1 g∶5 mL时,随着戊二醛(质量分数2.5%)的加入量增加,PEI-CMC的产率先增大后降低。在pH值1~14的范围内,溶液酸碱度的变化对PEI-CMC的交联度没有影响。PEI-CMC吸附剂对Cu2+、Pb2+和Cd2+的吸附量在实验范围内随pH升高而增加。PEI-CMC对Pb2+和Cu2+、Cd2+的吸附在90 min和180 min后分别达到平衡,吸附动力学符合准二级反应动力学模型。随着Cu2+、Pb2+和Cd2+初始浓度的增加,PEI-CMC对Cu2+、Pb2+和Cd2+的吸附量开始时快速增加,而后达到饱和,吸附等温数据符合Freundlich模型,最大吸附容量分别为Cu2+250.0mg/g、Pb2+635.9 mg/g、Cd2+142.8 mg/g。     

马铃薯淀粉黄原酸酯基高吸水树脂对重金属离子吸附特性的研究

探索了马铃薯淀粉黄原酸酯基高吸水树脂对Ni 2+、Co2+、Zn2+和Cu2+的二元混合溶液的平衡吸附,并对吸附机理进行了初步研究。结果表明:树脂在二元混合溶液中对Cu2+具有较好的选择性吸附能力。当树脂投放量为0.1g、金属离子初始浓度为100mg/L时,马铃薯淀粉黄原酸酯基高吸水树脂对Cu2+的吸附容量可达78.27mg/g。该高吸水树脂对重金属离子的静态吸附过程符合准二级动力学方程,且与高吸水树脂表面的物理吸附有关。     

β-环糊精-丙烯酸-丙烯酰胺接枝共聚型树脂在金属离子中的吸液行为研究

以β-环糊精、丙烯酸与丙烯酰胺为原料,采用反相悬浮接枝聚合法制备了β-环糊精基高吸水性树脂,系统研究了树脂在不同种金属离子中的吸液特征。实验结果表明金属离子和水之间存在着竟吸作用,3种金属阳离子对树脂的吸液效果影响大小分别是NaCl〉CaCl2〉FeCl3,树脂在CaCl2和FeCl3溶液中的吸液行为有过溶胀现象,且过溶胀现象随金属离子强度的升高而减弱。树脂在溶液浓度为0.005～0.1mol/L的不同阴离子溶液中的吸液倍率大小顺序为NaAc〉Na2CO3〉Na3PO4,阴离子离子半径越大,水合作用越强,吸液倍率越低。树脂在金属离子中吸液后的凝胶仍保持较好的三维网格结构,且网格大小与吸液倍率成正相关。     

磁性炭包铁纳米粒子对重金属离子的吸附性能

采用氩电弧等离子体法制备炭包铁纳米粒子,并用体积分数30%的H2O2氧化其外层非晶态类石墨碳层,研究炭包铁纳米粒子对水溶液中Cr、Ni、Cd、Pb、Co和Mn等金属离子的吸附和分离特性。结果表明,炭包铁非晶炭层的特殊结构可通过双氧水氧化处理使其表面产生羧基和羟基。在强碱性介质下,羟基和羧基强化了纳米颗粒表面的静电作用,提高了炭包铁对金属离子的吸附性能。当pH值为8.0～10.0时,炭包铁纳米粒子对Cr、Ni、Cd、Pb、Co和Mn的吸附率均超过90%,对重金属离子的吸附能力明显高于活性炭。     

AOPAN/RC纳米纤维膜的制备及对金属离子吸附性能

采用静电纺丝技术制备聚丙烯腈/醋酸纤维素(PAN/CA)纳米纤维膜,通过化学改性制备偕胺肟化聚丙烯腈/再生纤维素(AOPAN/RC)纳米纤维膜,研究了纳米纤维膜对单一金属离子(Fe~(3+))和混合金属离子(Cu~(2+)、Cd~(2+)、Fe~(3+))的吸附性能。通过扫描电镜、红外光谱、X射线能谱仪等测试对纳米纤维膜进行了表征,并通过静态接触角测定纳米纤维膜亲水性能。研究表明,改性后制备的AOPAN/RC纳米纤维膜的亲水性能得到较大改善,同时纳米纤维膜能够高效吸附溶液中的金属离子,纳米纤维膜对单一组分Fe~(3+)的饱和吸附可达411.21mg/g,对于混合金属离子溶液,纳米纤维膜对其吸附能力顺序为Fe~(3+)Cu~(2+)Cd~(2+),而且纳米纤维膜具备优良的重复使用能力。     

Studies on the applicability of alginate-entrapped Chryseomonas luteola TEM 05 for heavy metal biosorption

Chryseomonas luteola TEM 05 cells were entrapped both in alginate and chitosan coated alginate beads. Biosorption of metal ions on alginate beads was investigated by using a batch stirred system at pH 6.0, 25 degrees C, in initial metal concentration of 1.92 mM of Cr6+, 0.89 mM Cd2+ and 1.69 mM Co2+. Then, a process of competitive biosorption of these metal ions was described and compared to single metal ion adsorption in solution. The apparent equilibrium biosorption was reached within the 180 min of contact for all metals. Although the competitive biosorption capacities of the beads for all metal ions were lower than those of single conditions, Cd2+ biosorption on alginate and alginate-chitosan beads did not change significantly.     

Heavy metal precipitation by polycation-polyanion complex of PEI and its phosphonomethylated derivative

The removal of various heavy metal ions such as Cu2+, Co2+, Zn2+, Ni2+ and Pb2+ from aqueous solutions by precipitation with polyelectrolyte complex of PPEI and PEI was conducted. Heavy metal binding with PPEI was initially allowed to occur and then upon equilibration, PEI was added to initiate precipitation of the polyelectrolyte complex together with the heavy metal ion. The PPEI-PEI system was found effective for heavy metal scavenging purposes even in the presence of high concentrations of non-transition metal ions like Na+. Heavy metal concentration may be reduced beyond emission standards for industrial wastewaters. The PPEI-PEI polyelectrolyte complex was found to be more effective than traditional precipitation methods for the treatment of a representative electroless Ni plating waste solution.     

聚丙烯腈纤维改性条件优化及其对模拟电镀废水的净化作用

为了寻求低价、环保的电镀废水处理方案,将廉价的聚丙烯腈(PAN)纤维与羟胺试剂反应对PAN纤维进行改性,使其上氰基螯合获得偕胺肟基纤维。通过改变各种改性条件,探讨了改性条件对PAN改性纤维在重金属单离子溶液和多离子混合溶液中吸附性能的影响。结果表明:最佳改性条件为21.2 g/L PAN纤维,27.0 g/L盐酸羟胺,pH值为7.0,70℃下反应2 h;改性PAN纤维对模拟电镀废水中的Cu2+,Zn2+,Ni2+,Pb2+,Cd2+等重金属离子均有较好吸附性能,其中对Cd2+吸附效果最好,吸附量为55 mg/g;在多离子混合溶液中优先选择吸附Cd2+;改性PAN纤维再生效果优良,可重复利用。     

Effect of ionic strength on the adsorption of copper and chromium ions by vermiculite pure clay mineral

It is important to assess the effects of ionic strength when studying adsorption of metal ions on clay mineral because the background salt may complex metals and compete for adsorption sites. The sorption behavior of vermiculite pure clay mineral has been studied with respect to copper and chromium as a function of ionic strength in single metal ion solutions. Background electrolytes used in these experiments were KCl, NaCl and NH₄Cl. The studies were conducted by a batch method at temperature 25 °C. The adsorption capacity and adsorption energy for each metal ion were calculated from the Langmuir adsorption isotherm.Also the competitive adsorption behavior of some heavy metal ions such as Cr(III), Cu(II), Ni(II) and Co(II) by vermiculite pure clay mineral was studied. The result shows the competition between coexisting heavy metal cations for the same adsorption sites of an adsorbent. However, when trivalent metal was added to the solution it competitively replaced divalent ions that had been previously adsorbed onto the vermiculite pure clay mineral, resulting in the desorption of these metals into the solution.     

Removal and recovery of lead(II) from single and multimetal (Cd, Cu, Ni, Zn) solutions by crop milling waste (black gram husk)

The study reports removal of heavy metals when present singly or in binary and ternary systems by the milling agrowaste of Cicer arientinum (chickpea var. black gram) as the biosorbent. The biosorbent removed heavy metal ions efficiently from aqueous solutions with the selectivity order of Pb>Cd>Zn>Cu>Ni. The biosorption of metal ions by black gram husk (BGH) increased as the initial metal concentration increased. Biosorption equilibrium was established within 30 min, which was well described by the Langmuir and Freundlich adsorption isotherms. The maximum amount of heavy metals (qmax) adsorbed at equilibrium was 49.97, 39.99, 33.81, 25.73 and 19.56 mg/g BGH biomass for Pb, Cd, Zn, Cu and Ni, respectively. The biosorption capacities were found to be pH dependent and the maximum adsorption occurred at the solution pH 5. Efficiency of the biosorbent to remove Pb from binary and ternary solutions with Cd, Cu, Ni and Zn was the same level as it was when present singly. The presence of Pb in the binary and ternary solutions also did not significantly affect the sorption of other metals. Breakthrough curves for continuous removal of Pb from single, binary and ternary metal solutions are reported for inlet-effluent equilibrium. Complete desorption of Pb and other metals in single and multimetal solutions was achieved with 0.1 M HCl in both shake flask and fixed bed column studies. This is the first report of removal of the highly toxic Pb, Cd, and other heavy metals in binary and ternary systems based on the biosorption by an agrowaste. The potential of application for the treatment of solutions containing these heavy metals in multimetal solutions is indicated.     

Removal of Pb2+, Ag+, Cs+ and Sr2+ from aqueous solution by brewery's waste biomass

Heavy metal pollution is becoming a more and more serious environmental problem, posing threat to biota life. Biosorption is an alternative technology for the treatment of wastewater containing metal ions. In this paper, the removal of four metal ions, i.e., Pb2+, Ag+, Sr2+ and Cs+ by waste biomass of brewery was studied. The experimental results showed that metal uptake is a rapid process, which can be described by pseudosecond order kinetic model. The Langmuir adsorption isotherm was applied to correlate the equilibrium data and fitted quite well. The maximum biosorption capacities for four metal ions were 0.413 mmol Pb2+/g, 0.396 mmol Ag+/g, 0.091 mmol Sr2+/g and 0.076 mmol Cs+/g, respectively. The binding of metals was also discussed in term of several factors. The order of accumulated metal ions at equilibrium state on the molar basis was as follows: Pb2+>Ag+>Sr2+>Cs+, which positively correlated with their covalent index and electronegative and reversely correlated with dissociation constant.     

Untreated coffee husks as biosorbents for the removal of heavy metals from aqueous solutions

The objective of this work was to propose an alternative use for coffee husks (CH), a coffee processing residue, as untreated sorbents for the removal of heavy metal ions from aqueous solutions. Biosorption studies were conducted in a batch system as a function of contact time, initial metal ion concentration, biosorbent concentration and pH of the solution. A contact time of 72 h assured attainment of equilibrium for Cu(II), Cd(II) and Zn(II). The sorption efficiency after equilibrium was higher for Cu(II) (89-98% adsorption), followed by Cd(II) (65-85%) and Zn(II) (48-79%). Even though equilibrium was not attained in the case of Cr(VI) ions, sorption efficiency ranged from 79 to 86%. Sorption performance improved as metal ions concentrations were lowered. The experimental sorption equilibrium data were fitted by both Langmuir and Freundlich sorption models, with Langmuir providing the best fit (R2>0.95). The biosorption kinetics was determined by fitting first and second-order kinetic models to the experimental data, being better described by the pseudo-second-order model (R2>0.99). The amount of metal ions sorbed increased with the biosorbent concentration in the case of Cu(II) and Cr(VI) and did not present significant variations for the other metal ions. The effect of the initial pH in the biosorption efficiency was verified in the pH range of 4-7, and the results showed that the highest adsorption capacity occurred at distinct pH values for each metal ion. A comparison of the maximum sorption capacity of several untreated biomaterial-based residues showed that coffee husks are suitable candidates for use as biosorbents in the removal of heavy metals from aqueous solutions.     

Biosorption of Hg2+, Cd2+, and Zn2+ by Ca-alginate and immobilized wood-rotting fungus Funalia trogii

Funalia trogii biomass was immobilized in Ca-alginate gel beads. The live and heat inactivated immobilized forms were used for the biosorption of Hg2+, Cd2+ and Zn2+ ions by using plain Ca-alginate gel beads as a control system. The effect of pH was investigated and the maximum adsorption of metal ions on the Ca-alginate and both live and inactivated immobilized fungal preparations were observed at pH 6.0. The temperature change between 15 and 45 degrees C did not affect the biosorption capacity. The biosorption of Hg2+, Cd2+ and Zn2+ ions on the Ca-alginate beads and on both immobilized forms was studied in aqueous solutions in the concentration range of 30-600 mg/L. The metal biosorption capacities of the heat inactivated immobilized F. trogii for Hg2+, Cd2+ and Zn2+ were 403.2, 191.6, and 54.0 mg/g, respectively, while Hg2+, Cd2+ and Zn2+ biosorption capacities of the immobilized live form were 333.0, 164.8 and 42.1 mg/g, respectively. The same affinity order on a molar basis was observed for single or multi-metal ions (Hg2+ > Cd2+ > Zn2+). The Langmuir and the Freundlich type models were found to exhibit good fit to the experimental data. The experimental data were analyzed using the first-order (Langergren equations) and the second order (Ritchie equations). The experimental biosorption capacity with time is found to be best fit the second-order equations. The alginate-fungus system could be regenerated by washing with a solution of hydrochloride acid (10 mM). The percent desorption achieved was as high as 97. The biosorbents were reused in five biosorption-desorption cycles without significant loss of their initial biosorption capacity.