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采选冶废水中通常含有大量高浓度的重金属,如铅(Pb)、镉(Cd)等,这些重金属通过下渗扩散作用进入地下水中,造成地下水的污染[1]. 据统计,全国约有90%的地下水遭受不同程度的重金属污染[2]. 磁黄铁矿(FeS)对Pb、Cd等重金属均有显著的吸附性能[3 − 5],因此,这类有色金属矿山作业的副产物被作为吸附填料逐渐用在重金属污染的地下水的修复中,并显示出巨大的应用潜力[6 − 7]. 但FeS易团聚[3],也易被地下水中高价活性金属,如铁锰氧化物[8- 9]氧化而失活. 采用海藻酸钠、羧甲基纤维素钠等[3, 10 − 11]等包埋材料能够有效提升FeS的分散性和抗氧化性[12],改善其反应活性,增强其对重金属的吸附性能[3].
然而,目前对FeS的报道多集中于对单一重金属的吸附性能[10, 13],少有研究关注FeS对多金属的同步吸附. 以全球公认三大污染行业之一的电镀行业废水为例,通常含有大量Pb、Cd等重金属[6- 7]. 在FeS同步吸附多金属的过程中,由于重金属的电负性、吸附亲和力等差异,会竞争吸附点位,从而影响吸附效率[14]. 另外,在地下水环境中,MnO2等金属氧化物的广泛存在也会显著影响FeS的吸附性能[8, 15]. 因此,深入研究FeS同步吸附多金属的效率、机制以及MnO2的影响能为优化FeS组分和结构提供数据支撑和理论依据.
本研究选取环境友好且廉价易得的海藻酸钠(SA)[13],采用交联技术制备FeS-SA,提升其稳定性和吸附活性,研究FeS-SA对Pb和Cd的同步吸附性能以及吸附机制,探讨了Pb和Cd的竞争吸附以及MnO2对同步吸附的影响,以期为FeS-SA修复多金属污染地下水提供数据支撑和理论依据.
海藻酸钠改性硫化亚铁对Pb和Cd的同步吸附性能和机制
Simultaneous adsorption performance and mechanism of ferrous sulfide modified with sodium alginate (FeS-SA) towards Pb and Cd
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摘要: 采选冶废水下渗造成地下水Pb和Cd复合污染. 本文通过交联技术制备了海藻酸钠改性硫化亚铁(FeS-SA),研究了FeS-SA对水中Pb和Cd的同步吸附动力学、吸附容量及MnO2的影响,探讨了吸附机制及Pb的竞争吸附优势. 研究表明,相对于FeS,FeS-SA具有更高的分散性和稳定性. FeS-SA颗粒尺寸更小更均一,吸附性能得到显著提升. 相较于FeS,FeS-SA对Pb和Cd的吸附容量为637 mg·g−1和334 mg·g−1,分别提升了90.6%和114%,对Pb和Cd的吸附亲和力也提升了1个数量级. FeS-SA对Pb和Cd的吸附机制主要包括≡S−表面络合、离子交换、海藻酸钠(SA)吸附和≡Fe−OH表面络合吸附4种,其中≡S−表面络合贡献了近85%的吸附量. 混合体系中FeS-SA对Pb和Cd的吸附量为361 mg·g−1和127 mg·g−1. 与Pb相比(43.3%),Cd的吸附量较之单一体系下降幅度更大,为62.1%,这与FeS-SA对Pb具有更高的吸附亲和力和更快的吸附速率有关,因此,Pb在同步吸附中占据优势. 由于SA有效阻隔了MnO2对FeS的氧化,MnO2对FeS-SA同步吸附Pb和Cd无显著影响(<4%). FeS-SA吸附性能和抗环境干扰性能的显著提升以及吸附机制的多样化表明其在环境修复中具有很大的应用潜力,本研究为FeS-SA在修复重金属复合污染地下水中的应用提供了数据支持和理论依据.
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关键词:
- 海藻酸钠改性硫化亚铁 /
- 同步吸附 /
- 铅 /
- 镉 /
- 吸附机制.
Abstract: Multi-polluted groundwater from lead (Pb) and cadmium (Cd) was caused by the infiltration of wastewater from mining, dressing and smelting industries. Ferrous sulfide modified with sodium alginate (FeS-SA) was prepared via crosslinking technology. The simultaneous adsorption kinetics and adsorption capacity of FeS-SA towards Pb and Cd in aqueous solution and the effects of MnO2 on adsorption were studied. The adsorption mechanism and competitive adsorption advantage of Pb were discussed. Generally, higher dispersion and stability were observed for FeS-SA than that of in non-modified FeS. Smaller and more homogeneous particle size was obtained for FeS-SA, and hence, the adsorption performance was significantly improved. The adsorption capacity of FeS-SA towards Pb and Cd were 637 mg·g−1 and 334 mg·g−1, increased by 90.6% and 114%, respectively compared with FeS. Moreover, the adsorption affinity of FeS-SA towards Pb and Cd was increased by one order of magnitude. Four adsorption mechanisms, including ≡S− surface complexation, ion exchange, sodium alginate adsorption, and ≡Fe−OH surface complexation contributed in adsorption process. In particular, ≡S− surface complexation dominated in adsorption, accounting for 85%. Furthermore, the adsorption capacity of FeS-SA towards Pb and Cd in multi-polluted system were 361 mg·g−1 and 127 mg·g−1, respectively. It was noteworthy that the adsorption capacity of Cd decreased by 62.1% more than that of Pb (43.3%) compared with single system. Lead was found to be dominant in simultaneous adsorption due to higher adsorption affinity and faster adsorption rate with FeS-SA. More importantly, MnO2 had no significant effect (<4%) on the simultaneous adsorption of Pb and Cd due to the effective inhibition by sodium alginate to FeS oxidation by MnO2. Overall, the significant improvement in adsorption performance and resistance to environmental interference, as well as the diversification of adsorption mechanism, indicating that FeS-SA had great potential in environmental remediation. This study provided the data support and theoretical basis for the application of FeS-SA in the remediation of groundwater contaminated by heavy metals. -
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[1] 钱建平, 李伟, 张力, 等. 地下水中重金属污染来源及研究方法综析[J]. 地球与环境, 2018, 46(6): 613-620. QIAN J P, LI W, ZHANG L, et al. Source and research status of heavy metal pollution in groundwater: A review[J]. Earth and Environment, 2018, 46(6): 613-620 (in Chinese).
[2] HAN D M, CURRELL M J, CAO G L. Deep challenges for China’s war on water pollution[J]. Environmental Pollution, 2016, 218: 1222-1233. doi: 10.1016/j.envpol.2016.08.078 [3] SUN Y, LIU Y L, LOU Z M, et al. Enhanced performance for Hg(Ⅱ) removal using biomaterial (CMC/gelatin/starch) stabilized FeS nanoparticles: Stabilization effects and removal mechanism[J]. Chemical Engineering Journal, 2018, 344: 616-624. doi: 10.1016/j.cej.2018.03.126 [4] ZHAO Y, TIAN S T, GONG Y Y, et al. Efficient removal of lead from water using stabilized iron sulfide nanoparticles: Effectiveness and effects of stabilizer [J]. Water, Air, & Soil Pollution, 2019, 230(6): 1-14. [5] PARK M, LEE K S, RYU J, et al. Investigation of Cd(Ⅱ) sorption by mackinawite (FeS) under anoxic conditions[J]. Journal of Analytical Science and Technology, 2022, 13(1): 1-11. doi: 10.1186/s40543-021-00310-5 [6] 苗立永, 员玉良, 王铮. FeS流化床处理电镀废水中重金属离子的试验研究[J]. 工业水处理, 2008, 28(9): 21-24. doi: 10.3969/j.issn.1005-829X.2008.09.006 MIAO L Y, YUN Y L, WANG Z. Experimental research of the treatment of heavy metal ions in electroplating wastewater with FeS fluid bed[J]. Industrial Water Treatment, 2008, 28(9): 21-24 (in Chinese). doi: 10.3969/j.issn.1005-829X.2008.09.006
[7] 张越. FeS流化床处理电镀废水的试验研究[J]. 山西化工, 2016, 36(5): 133-136. ZHANG Y. FeS processing galvanization waste water fluid bed craft research[J]. Shanxi Chemical Industry, 2016, 36(5): 133-136 (in Chinese).
[8] SCHIPPERS A, JØRGENSEN B B. Biogeochemistry of pyrite and iron sulfide oxidation in marine sediments[J]. Geochimica et Cosmochimica Acta, 2002, 66(1): 85-92. doi: 10.1016/S0016-7037(01)00745-1 [9] SCHIPPERS A, JØRGENSEN B B. Oxidation of pyrite and iron sulfide by manganese dioxide in marine sediments[J]. Geochimica et Cosmochimica Acta, 2001, 65(6): 915-922. doi: 10.1016/S0016-7037(00)00589-5 [10] GONG Y Y, TANG J C, ZHAO D Y. Application of iron sulfide particles for groundwater and soil remediation: A review[J]. Water Research, 2016, 89: 309-320. doi: 10.1016/j.watres.2015.11.063 [11] CHEN Y N, LIANG W Y, LI Y P, et al. Modification, application and reaction mechanisms of nano-sized iron sulfide particles for pollutant removal from soil and water: A review[J]. Chemical Engineering Journal, 2019, 362: 144-159. doi: 10.1016/j.cej.2018.12.175 [12] DUAN J, JI H D, ZHAO X, et al. Immobilization of U(Ⅵ) by stabilized iron sulfide nanoparticles: Water chemistry effects, mechanisms, and long-term stability[J]. Chemical Engineering Journal, 2020, 393: 124692. doi: 10.1016/j.cej.2020.124692 [13] 凌海波, 全森, 侯松, 等. 海藻酸钠改性硫化亚铁对水中Cr(Ⅵ)去除性能研究[J]. 环境科学与技术, 2022, 45(4): 54-60. LING H B, QUAN S, HOU S, et al. Sodium alginate modified ferrous sulfide for the removal of Cr(Ⅵ)from aqueous system[J]. Environmental Science & Technology, 2022, 45(4): 54-60 (in Chinese).
[14] 王琼杰, 张勇, 张阳阳, 等. 老化微塑料对水体中重金属铜和锌的吸附行为研究[J]. 环境科学学报, 2021, 41(7): 2712-2726. WANG Q J, ZHANG Y, ZHANG Y Y, et al. Adsorption of heavy metal ions Cu2+ and Zn2+ onto UV-aged microplastics in aquatic system[J]. Acta Scientiae Circumstantiae, 2021, 41(7): 2712-2726 (in Chinese).
[15] 余东, 周金龙, 张杰, 等. 新疆喀什地区地下水铁锰水文地球化学及演化规律[J]. 环境科学学报, 2021, 41(6): 2169-2181. YU D, ZHOU J L, ZHANG J, et al. Hydrogeochemistry and evolution of iron and manganese in groundwater in Kashgar, Xinjiang[J]. Acta Scientiae Circumstantiae, 2021, 41(6): 2169-2181 (in Chinese).
[16] 邓智瀚. 海藻酸钠改性FeS纳米颗粒处理Cr(Ⅵ)污染土壤的机理及性能研究 [D]. 成都: 成都理工大学, 2019. DENG Z H. Study on mechanism and properties of repair Cr(Ⅵ) in soil using FeS nanoparticles modified sodium alginate [D]. Chengdu: Chengdu University of Technology, 2019(in Chinese).
[17] SUN M Y, CHENG G H, GE X L, et al. Aqueous Hg(Ⅱ) immobilization by chitosan stabilized magnetic iron sulfide nanoparticles[J]. Science of the Total Environment, 2018, 621: 1074-1083. doi: 10.1016/j.scitotenv.2017.10.119 [18] FENG D M, ZHANG X, SUN Y, et al. Surface-defective FeS2 for electrochemical NH3 production under ambient conditions[J]. Nano Materials Science, 2020, 2(2): 132-139. doi: 10.1016/j.nanoms.2019.07.002 [19] WANG Y X, YANG J P, CHOU S L, et al. Uniform yolk-shell iron sulfide-carbon nanospheres for superior sodium-iron sulfide batteries[J]. Nature Communications, 2015, 6: 8689. doi: 10.1038/ncomms9689 [20] MATAMOROS V A, CESPEDES O, JOHNSON B R G, et al. A highly reactive precursor in the iron sulfide system[J]. Nature Communications, 2018, 9: 3125. doi: 10.1038/s41467-018-05493-x [21] LI H, ZHAO T L, QIAN F J, et al. A model of extracellular polymeric substances on crystal growth and morphogenesis of struvite: Effects of sodium alginate[J]. Powder Technology, 2021, 380: 80-88. doi: 10.1016/j.powtec.2020.11.037 [22] WEI L, HONG T Q, LIU H B, et al. The effect of sodium alginate on struvite crystallization in aqueous solution: A kinetics study[J]. Journal of Crystal Growth, 2017, 473: 60-65. doi: 10.1016/j.jcrysgro.2017.03.039 [23] GAO X P, GUO C, HAO J J, et al. Adsorption of heavy metal ions by sodium alginate based adsorbent-a review and new perspectives[J]. International Journal of Biological Macromolecules, 2020, 164: 4423-4434. doi: 10.1016/j.ijbiomac.2020.09.046 [24] 杨晓武, 李志刚, 李培枝, 等. 海藻酸钠凝胶海绵体的制备及其对Pb2+和Cu2+的吸附[J]. 精细化工, 2021, 38(1): 162-168. YANG X W, LI Z G, LI P Z, et al. Preparation of sodium alginate gel sponge and its adsorption for Pb2+ and Cu2+[J]. Fine Chemicals, 2021, 38(1): 162-168 (in Chinese).
[25] CÓRDOVA B M, JACINTO C R, ALARCÓN H, et al. Chemical modification of sodium alginate with thiosemicarbazide for the removal of Pb(II) and Cd(II) from aqueous solutions[J]. International Journal of Biological Macromolecules, 2018, 120: 2259-2270. doi: 10.1016/j.ijbiomac.2018.08.095 [26] MOHAMED ANWAR P, MURUGANANTHAM S, KARUNANITHY M, et al. Optical, structural and electrical properties of AgSbO3 nanotips prepared by thermal evaporation technique for thermoelectric effect applications[J]. Materials Today:Proceedings, 2021, 36: 492-498. doi: 10.1016/j.matpr.2020.05.148 [27] GONG Y Y, LIU Y Y, XIONG Z, et al. Immobilization of mercury by carboxymethyl cellulose stabilized iron sulfide nanoparticles: Reaction mechanisms and effects of stabilizer and water chemistry[J]. Environmental Science & Technology, 2014, 48(7): 3986-3994. [28] ZOU Q R, WANG W Y, ZHANG T, et al. Simultaneous removal of Cr(Ⅵ), Cd, and Pb from aqueous solution by iron sulfide nanoparticles: Influencing factors and interactions of metals[J]. Chinese Journal of Chemical Engineering, 2021, 40: 245-255. doi: 10.1016/j.cjche.2020.10.021 [29] DU H H, CHEN W L, CAI P, et al. Competitive adsorption of Pb and Cd on bacteria-montmorillonite composite[J]. Environmental Pollution, 2016, 218: 168-175. doi: 10.1016/j.envpol.2016.08.022 [30] ZHANG M J, ZHU L Y, HE C H, et al. Adsorption performance and mechanisms of Pb(Ⅱ), Cd(Ⅱ), and Mn(Ⅱ) removal by a β-cyclodextrin derivative[J]. Environmental Science and Pollution Research International, 2019, 26(5): 5094-5110. doi: 10.1007/s11356-018-3989-4 [31] HYUN S P, KIM B A, SON S, et al. Cadmium(Ⅱ) removal by mackinawite under anoxic conditions[J]. ACS Earth and Space Chemistry, 2021, 5(6): 1306-1315. doi: 10.1021/acsearthspacechem.0c00276 [32] TAN K L, HAMEED B H. Insight into the adsorption kinetics models for the removal of contaminants from aqueous solutions[J]. Journal of the Taiwan Institute of Chemical Engineers, 2017, 74: 25-48. doi: 10.1016/j.jtice.2017.01.024 [33] COLES C A, RAO S R, YONG R N. Lead and cadmium interactions with mackinawite: retention mechanisms and the role of pH[J]. Environmental Science & Technology, 2000, 34(6): 996-1000. [34] GE Q L, TIAN Q, WANG S F, et al. Highly efficient removal of lead/cadmium by phosphoric acid-modified hydrochar prepared from fresh banana peels: Adsorption mechanisms and environmental application[J]. Langmuir:the ACS Journal of Surfaces and Colloids, 2022, 38(49): 15394-15403. doi: 10.1021/acs.langmuir.2c02693 [35] WU J, WANG X B, ZENG R J. Reactivity enhancement of iron sulfide nanoparticles stabilized by sodium alginate: Taking Cr (Ⅵ) removal as an example[J]. Journal of Hazardous Materials, 2017, 333: 275-284. doi: 10.1016/j.jhazmat.2017.03.023