Guerra Denis L, Viana Rúbia R, Airoldi Claudio
Chemistry Institute, State University of Campinas, São Paulo, Brazil.
J Hazard Mater. 2009 Sep 15;168(2-3):1504-11. doi: 10.1016/j.jhazmat.2009.03.034. Epub 2009 Mar 18.
Diquite (D) and bentonite (B) mineral samples from the Amazon region, Brazil, were modified by MTTZ derivative (5-mercapto-1-methyltetrazole) using heterogeneous route. These materials were characterized by textural and elemental analysis, transmission electron microscopy (TEM), power X-ray diffraction and (13)C NMR spectroscopy. The chemically modified clay (D(MTTZ) and B(MTTZ)) samples showed modification of its physical-chemical properties including: specific area 41.4 (B) to 398.5m(2)g(-1) (B(MTTZ)) and 25.0 (D) to 178.8m(2)g(-1) (D(MTTZ)). The adsorption experiments performed under batch process with Th(IV) concentration, pH and contact time as variables. The ability of these materials to remove thorium from aqueous solution was followed by a series of adsorption isotherms adjusted to a Sips equation at room temperature and pH 2.0, with variable concentration of Th(IV). The maximum number of moles adsorbed was determined to be 10.45 x 10(-2) and 12.76 x 10(-2)mmol g(-1) for D(MTTZ) and B(MTTZ), respectively. The energetic effects (Delta(int)H degrees , Delta(int)G degrees and Delta(int)S degrees ) caused by thorium cation adsorption were determined through calorimetric titrations.
采用非均相路线，用MTTZ衍生物（5-巯基-1-甲基四唑）对来自巴西亚马逊地区的迪夸特（D）和膨润土（B）矿物样品进行了改性。通过结构和元素分析、透射电子显微镜（TEM）、粉末X射线衍射和（13）C核磁共振光谱对这些材料进行了表征。化学改性粘土（D（MTTZ）和B（MTTZ））样品的物理化学性质发生了改变，包括：比表面积从41.4（B）变为398.5m²g⁻¹（B（MTTZ）），从25.0（D）变为178.8m²g⁻¹（D（MTTZ））。以钍（IV）浓度、pH值和接触时间为变量，在间歇过程中进行吸附实验。在室温及pH值为2.0、钍（IV）浓度可变的条件下，通过一系列调整为Sips方程的吸附等温线，研究了这些材料从水溶液中去除钍的能力。对于D（MTTZ）和B（MTTZ），测定的最大吸附摩尔数分别为10.45×10⁻²和12.76×10⁻²mmol g⁻¹。通过量热滴定法测定了钍阳离子吸附引起的能量效应（Δ(int)H°、Δ(int)G°和Δ(int)S°）。
