凹凸棒土负载硫化纳米零价铁对水中Cu(Ⅱ)的去除机理研究
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摘要
针对纳米零价铁易团聚及表面形成钝化层的缺点,本文以凹凸棒土为载体、以硫代硫酸钠为硫化试剂,制备了凹凸棒土负载硫化纳米零价铁(S-nZVI@ATP)复合材料,并考察了复合材料对水中Cu(Ⅱ)的去除效果。由SEM可观察到,经过凹凸棒土负载及硫化改性后的纳米零价铁串珠状结构变短,且被分散为单个的球形颗粒;比表面积测定结果表明,S-nZVI@ATP复合材料的BET比表面积为46.04m~2/g,与纳米零价铁相比提高了约1.35倍;由TEM观察到,经硫化的纳米零价铁颗粒界面处包裹了一层FeS,粒径由57.6nm增至118.5nm。S-nZVI@ATP复合材料去除水中Cu(Ⅱ)的机理主要是硫化纳米铁界面处的Fe~0将Cu~(2+)还原为Cu~0以及FeS转化为溶度积更小的CuS,该过程符合Langmuir-Hinshelwood吸附/还原模型和Langmuir等温吸附模型。本实验条件下,复合材料对Cu(Ⅱ)的最大吸附-还原量可达9.25mmol/g(587.8mg/g)。
Aiming at overcoming the disadvantages of aggregation and passivation of nanoscale zerovalent iron,the attapulgite-loaded sulfide-modified nanoscale zero-valent iron was prepared by using attapulgite as carrier and sodium thiosulfate as sulfidation reagent,and its removal of Cu(Ⅱ)from the aqueous solution was investigated.It can be obversed by SEM that the bead-like structure of nZVI after attapulgite loading and sulfidation modification becomes shorter and was even dispersed into individual spherical particles.The measured results of specific surface areas indicate that the BET specific surface area of the S-nZVI@ATP composite is 46.04 m~2/g,which is around 1.35 times higher than that of nZVI.In addition,according to the obvervation by TEM,a layer of FeS is wrapped around the surface of a sulfide-modified nZVI particle,and the corresponding particle size increases from 57.6 nm to 118.5 nm after sulfidation.The mechanism of Cu(Ⅱ)removal by S-nZVI@ATP composite can be attributed to the reduction of Cu~(2+)to Cu~0 by Fe~0 at the inferface of sulfide-modified nZVI in aqueous solution and the conversion of FeS to CuS with a smaller solubility product.The removal process fits well with Langmuir-Hinshelwood adsorption/reduction model and Langmuir adsorption isotherm model.Under the experiment conditions,the maximum adsorption-reduction capability of Cu(Ⅱ)by composite reaches 9.25 mmol/g(587.8 mg/g).
Aiming at overcoming the disadvantages of aggregation and passivation of nanoscale zerovalent iron,the attapulgite-loaded sulfide-modified nanoscale zero-valent iron was prepared by using attapulgite as carrier and sodium thiosulfate as sulfidation reagent,and its removal of Cu(Ⅱ)from the aqueous solution was investigated.It can be obversed by SEM that the bead-like structure of nZVI after attapulgite loading and sulfidation modification becomes shorter and was even dispersed into individual spherical particles.The measured results of specific surface areas indicate that the BET specific surface area of the S-nZVI@ATP composite is 46.04 m~2/g,which is around 1.35 times higher than that of nZVI.In addition,according to the obvervation by TEM,a layer of FeS is wrapped around the surface of a sulfide-modified nZVI particle,and the corresponding particle size increases from 57.6 nm to 118.5 nm after sulfidation.The mechanism of Cu(Ⅱ)removal by S-nZVI@ATP composite can be attributed to the reduction of Cu~(2+)to Cu~0 by Fe~0 at the inferface of sulfide-modified nZVI in aqueous solution and the conversion of FeS to CuS with a smaller solubility product.The removal process fits well with Langmuir-Hinshelwood adsorption/reduction model and Langmuir adsorption isotherm model.Under the experiment conditions,the maximum adsorption-reduction capability of Cu(Ⅱ)by composite reaches 9.25 mmol/g(587.8 mg/g).
引文
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[14]黎珊,戴红旗,孔泳,等.凹凸棒土的应用研究进展[J].化工进展,2013,32(12):2934-2938.
[15]陈玉伟,王建龙.零价铁(ZVI)去除Cu2+的特性及机制研究[J].环境科学,2009,30(11):3353-3357.
[16]何桂春,陈健,丁军,等.活性炭负载纳米零价铁去除矿山废水中的Cu2+[J].有色金属科学与工程,2016,7(5):119-124.
[17]龚璇.纳米Fe/Ni的负载和改性及其去除重金属和氯代有机物性能与机理研究[D].武汉:武汉科技大学,2018:13-43.
[18]刘红,龚璇,范先媛,等.凹凸棒土负载纳米Fe/Ni的制备及其去除水中Zn(II)性能研究[J].武汉科技大学学报,2018,41(5):370-375.
[2] Omar W A,Zaghhloul K H,Abdel-Khalek A A,et al.Genotoxic effects of metal pollution in two fish species,Oreochromis niloticus and Mugil cephalus,from highly degraded aquatic habitats[J].Mutation Research/Genetic Toxicology and Environmental Mutagenesis,2012,746(1):7-14.
[3] 邵利芬,杨玉杰,姚曙光,等.含铜电镀废水处理技术研究进展[J].工业用水与废水,2007,38(3):13-16.
[4] 陈郁,全燮.零价铁处理污水的机理及应用[J].环境科学研究,2000,13(5):24-27.
[5] Zou Y D,Wang X X,Khan A,et al.Environmental remediation and application of nanoscale zerovalent iron and its composites for the removal of heavy metal ions:a review[J].Environmental Science and Technology,2016,50(14):7290-7304.
[6] Gillham R W,O’Hannesin S F.Enhanced degradation of halogenated aliphatics by zero-valent iron[J].Ground Water,1994,32(6):958-967.
[7] Orth W S,Gillham R W.Dechlorination of trichloroethene in aqueous solution using Fe0[J].Environmental Science and Technology,2015,30(1):66-71.
[8] 龚璇,刘红,范先媛,等.凹凸棒土负载纳米铁/镍去除水中Zn(II)的性能与机理研究[J].黑龙江大学自然科学学报,2018,35(2):200-205.
[9] 张环,金朝晖,韩璐,等.负载型纳米铁化学反硝化法去除硝酸盐氮的研究[J].中国给水排水,2006,22(15):83-87.
[10]刘金玲,陈嘉炼,王珊珊,等.活性炭负载纳米铁的制备及对甲基橙去除效果的研究[J].广州化工,2016,44(7):73-76.
[11]汤晶,汤琳,冯浩朋,等.硫化纳米零价铁去除水体污染物的研究进展[J].化学学报,2017,75(6):575-582.
[12]Su Y M,Adeyemi A S,Keller A A,et al.Magnetic sulfide-modified nanoscale zerovalent iron(S-nZVI)for dissolved metal ion removal[J].Water Research,2015,74:47-57.
[13]关文贤.改性凹凸棒土负载纳米铁的制备及性能表征[D].广州:广东工业大学,2016:13-42.
[14]黎珊,戴红旗,孔泳,等.凹凸棒土的应用研究进展[J].化工进展,2013,32(12):2934-2938.
[15]陈玉伟,王建龙.零价铁(ZVI)去除Cu2+的特性及机制研究[J].环境科学,2009,30(11):3353-3357.
[16]何桂春,陈健,丁军,等.活性炭负载纳米零价铁去除矿山废水中的Cu2+[J].有色金属科学与工程,2016,7(5):119-124.
[17]龚璇.纳米Fe/Ni的负载和改性及其去除重金属和氯代有机物性能与机理研究[D].武汉:武汉科技大学,2018:13-43.
[18]刘红,龚璇,范先媛,等.凹凸棒土负载纳米Fe/Ni的制备及其去除水中Zn(II)性能研究[J].武汉科技大学学报,2018,41(5):370-375.