摘要
研究了腐殖酸在水合MnO2 (S) (δMnO2 )表面的吸附行为 .考察了不同分子量分布范围腐殖酸的吸附性能 ,探讨了阳离子对吸附行为的影响及其可能作用机理 ,并利用FTIR光谱对吸附行为进行了光谱学研究 .结果发现 ,具有较高分子量的腐殖酸HAa 的吸附去除率比具有较低分子量的腐殖酸HAb 高 3 0 % ,表明腐殖酸分子量越大越倾向于吸附在δMnO2 表面 .Ca2 + 较Mg2 + 更能促进腐殖酸在δMnO2 表面的吸附 ;紫外 -可见吸收光谱分析表明Ca2 + 较Mg2 + 具有更强的与腐殖酸络合的能力 ;此外 ,ζ电位测定发现 ,1 0mmol·L- 1 Mg2 + 使δMnO2 的 ζ电位由 -3 7mV(pH =7 9)升高至 -9mV(pH =6 5 ) ,而 1 0mmol·L- 1 Ca2 + 则使ζ电位升高至 + 7mV(pH =7 2 ) .FTIR光谱的结果证实了腐殖酸在δMnO2 表面的吸附 ,并表明腐殖酸的羧基及δMnO2 的表面羟基 (Mn OH)在吸附过程中起着重要作用 .上述结果表明 ,腐殖酸性质。
The adsorptive behavior of humic acid on hydrous MnO_2(S) (δMnO_2) is investigated. Effects of such parameters as molecular weight of humic acid and divalent cation species on adsorptive behavior are investigated, and possible mechanisms that divalent cation involves in are proposed. FTIR spectra are subsequently employed for further spectroscopy study. Results of this study show approximate 30% more adsorption of humic acid with higher moleculer weight(HA_a) on δMnO_2 than that with lower molecular weight(HA_b), indicating that humic acid with higher molecular weight exhibits more tendency of adsorbing on δMnO_2. Ca^(2+) facilitates more humic acid adsorption than Mg^(2+) does; UV-Vis spectra demonstrate that Ca^(2+) possesses higher capabilities of complexing with acidic functional groups of humic acid than Mg^(2+) does; furthermore, 1.0mmol·L^(-1) Ca^(2+) increases ζ potential of δMnO_2 from -37mV (pH=7.9) to +7mV (pH=7.2), while 1.0mmol·L^(-1) Mg^(2+) increases to lower value as -9mV (pH=6.5), correspondingly. FTIR spectra demonstrate humic acid adsorption on δMnO_2, showing that -COO^- functional groups within humic acid and surface Mn-OH groups of δMnO_2 have great influence on adsorptive behavior. Such factors as humic acid characteristics and background cation have important effects on adsorption.
出处
《环境科学学报》
CAS
CSCD
北大核心
2005年第3期351-355,共5页
Acta Scientiae Circumstantiae
基金
国家"8 63"计划重大科技专项课题 (2 0 0 2AA60 114 0 )
