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
张凤姣 1娄伟 2赵泽州 1石瑶 1李致达 1盛安旭 1王琳玲 1昝飞翔 1吴晓晖 1陈静1
作者信息
- 1. 华中科技大学环境科学与工程学院,武汉,430074
- 2. 华中科技大学环境科学与工程学院,武汉,430074;湖南省工业固废资源化与安全处置工程技术研究中心,长沙,410032
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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.
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.
关键词
海藻酸钠改性硫化亚铁/同步吸附/铅/镉/吸附机制Key words
ferrous sulfide modified with sodium alginate/simultaneous adsorption/lead/cadmium/adsorption mechanism引用本文复制引用
基金项目
国家重点研发计划(2019YFC1805202)
出版年
2024
NETL
NSTL
万方数据