CERAR - Centre for Environmental Risk Assessment and Remediation, Building X, University of South Australia, Mawson Lakes, SA 5095, Australia.
J Hazard Mater. 2011 Nov 15;195:155-61. doi: 10.1016/j.jhazmat.2011.08.016. Epub 2011 Aug 12.
Organoclays are increasingly being used to remediate both contaminated soils and waste water. The present study was attempted to elucidate the structural evolution of bentonite based organoclays prepared from a commercially available, low-cost alkyl ammonium surfactant Arquad(®) 2HT-75. XRD, FTIR, SEM and zeta potential measurement were used to characterise the organoclays. In particular, the relationship between surface charge characteristics of the organoclays and their ability to remediate organic contaminants such as phenol and p-nitrophenol was investigated. The investigation revealed that the arrangement and conformation of surfactant molecules in the bentonite became more regular, ordered and solid-like as of Arquad(®) 2HT-75 loading increased. This also led to the formation of a positive zeta potential on the surface of organobentonites prepared with 3.57:1 and 4.75:1 surfactant-clay (w/w) ratio. The zeta potential values decreased with increasing pH of the suspension. The adsorption data of phenol and p-nitrophenol were best fitted to Freundlich isotherm model. The adsorption was controlled by multiple mechanisms of partitioning, physico-sorption and chemisorption. The outcomes of this study are useful for the synthesis of low cost organobentonite adsorbents for the remediation of ionisable organic contaminants such as phenol and p-nitrophenol from waste water.
有机黏土越来越多地被用于修复污染土壤和废水。本研究试图阐明从商业可得的低成本烷基铵表面活性剂 Arquad®2HT-75 制备的膨润土基有机黏土的结构演变。使用 XRD、FTIR、SEM 和 ζ 电位测量对有机黏土进行了表征。特别是，研究了有机黏土的表面电荷特性与其修复有机污染物（如苯酚和对硝基苯酚）的能力之间的关系。研究表明，随着 Arquad®2HT-75 负载量的增加，表面活性剂分子在膨润土中的排列和构象变得更加规则、有序和固态。这也导致在表面活性剂-黏土（w/w）比为 3.57:1 和 4.75:1 时制备的有机膨润土表面形成正 ζ 电位。ζ 电位值随悬浮液 pH 的增加而降低。苯酚和对硝基苯酚的吸附数据最符合 Freundlich 等温线模型。吸附受分配、物理吸附和化学吸附等多种机制控制。本研究的结果对于合成低成本有机膨润土吸附剂用于修复废水中可离子化有机污染物（如苯酚和对硝基苯酚）非常有用。
