原位生成纳米MnO_(2)胶体对Mn^(2+)的吸附机理实验研究  

Experimental Study on Mechanism of Adsorption of Mn^(2+)by In-situ Generated Nano-MnO_(2) Colloids

作　　者：张欣宇 唐玉朝[1] 王坤[1] 黄显怀[1] 尹翠琴[2] 高和气 伍昌年[1] 黄健[1] 李卫华[1] ZHANG Xinyu;TANG Yuchao;WANG Kun;HUANG Xianhuai;YIN Cuiqin;GAO Heqi;WU Changnian;HUANG Jian;LI Weihua(Anhui Provincial Key Lab of Environmental Pollution Control and Resource/Reuse,Anhui Jianzhu University,Hefei 230601,China;Hefei Water Supply Group Co.,Ltd.,Hefei 230011,China)

机构地区：[1]安徽建筑大学,环境污染控制与废弃物资源化利用安徽省重点实验室,安徽合肥230601 [2]合肥供水集团有限公司,安徽合肥230011

出　　处：《环境科学与技术》2024年第4期16-25,共10页Environmental Science & Technology

基　　金：国家自然科学基金项目(52370001);安徽省自然科学基金项目(2208085US20);安徽省教育厅创新团队项目(2022AH010019)。

摘　　要：该文用Mn^(2+)离子与KMnO4溶液反应,得到原位生成纳米MnO_(2)胶体,用该胶体颗粒对水中Mn^(2+)离子进行吸附。对原位生成MnO_(2)胶体采用光学显微镜、能谱分析、傅立叶变换红外光谱、粒度和Zeta电位分析仪进行表征,探究了原位生成MnO_(2)胶体对Mn^(2+)离子吸附机理,考察了原位生成MnO_(2)胶体浓度、吸附温度、吸附时间以及pH对原位生成的MnO_(2)胶体对Mn^(2+)离子吸附容量的影响。结果表明,原位生成MnO_(2)胶体对Mn^(2+)离子的吸附符合Freundlich吸附模型(R^(2)>0.97),说明发生了多层次吸附,最佳吸附时间为30 min,符合伪二级动力学方程(R^(2)>0.98);低浓度原位生成的MnO_(2)胶体吸附容量相较于高浓度更大,1 mg/L原位生成的MnO_(2)胶体在25℃下吸附容量能达到2 022.19 mg/g;低温有利于原位生成的MnO_(2)胶体对Mn^(2+)离子的物理吸附,高温有利于其表面羟基与Mn^(2+)离子络合;pH=8.03时原位生成的Mn O_(2)胶体对Mn^(2+)离子的吸附容量约为p H=4.56时的4倍且表面Mn-OH和羟基增多,45 mg/L的MnO_(2)胶体吸附容量达到1 647.13 mg/g;pH=4.56和pH=8.03条件下原位生成的MnO_(2)胶体吸附Mn^(2+)离子后Zeta电势值分别为-12.6、-1.10 m V,原位生成纳米MnO_(2)胶体对水中Mn^(2+)离子的吸附实际上是物理吸附、静电吸引、表面配位的共同作用。Nano MnO_(2) colloids were in-situ generated at laboratory scale by means of the reaction of Mn^(2+)ions with KMnO4 in solution,which were used to adsorb Mn^(2+)ions in water.The MnO_(2) colloids in-situ produced was then characterized by opti-cal microscopy(OM),energy dispersive spectroscopy(EDS),Fourier transform infrared spectroscopy(FTIR),and particle-size/zeta-potential analyzers to explore the adsorption mechanism.The effect of the concentration of MnO_(2) colloids,adsorp-tion temperature,adsorption time,and pH value on the adsorption capacity was investigated.The results obtained showed that the adsorption of Mn^(2+)ions onto the MnO_(2) colloids fit the Freundlich adsorption model(R^(2)>0.97),indicating that multi-level adsorption had occurred,the optimal adsorption process took about 30 minutes,so it conformed to the pseudo second-order ki-netic equation(R^(2)>0.98)as well;the adsorption capacity of MnO_(2) colloids generated in situ in low Mn^(2+)concentration was greater than that in high concentrations,and the adsorption capacity of the MnO_(2) colloids in Mn^(2+)concentration of 1 mg/L could be as high as 2022.19 mg/g at 25℃;low temperature was conducive to the physical adsorption of Mn^(2+)ions by the MnO_(2) colloids,while high temperature was conducive to the complexation of surface hydroxyl groups with Mn^(2+)ions;and at a pH of 8.03 the adsorption capacity of the MnO_(2) was approx.four times that at a pH of 4.56,in addition the surface Mn-OH and hydroxyl groups grew,and the adsorption capacity of MnO_(2) colloid concentration of 45 mg/L could reache 1647.13 mg/g.Furthermore,after Mn^(2+)ions having been adsorpted on MnO_(2) colloids the zeta potential value was equal to-12.6 mV at pH of 4.56,and-1.10 mV at pH of 8.03.Generally speaking,the adsorption of Mn^(2+)ions in water by in-situ generated nano MnO_(2) colloids is actually a combination of physical adsorption,electrostatic attraction and surface coordination.

关 键 词：原位生成 纳米MnO_(2) 吸附除锰 影响因素 吸附机制 

分 类 号：X131[环境科学与工程—环境科学] TU991.21[建筑科学—市政工程]