改性纳米二氧化钛分离富集电感耦合等离子体原子发射光谱法测定地质样品中金钯铑

Determination of gold,palladium and rhodium in geological samples by inductively coupled plasma atomic emission spectrometry after separation and enrichment with modified nano-titanium dioxide

纳米TiO2用二苯基硫脲修饰后得到改性纳米TiO2,改性纳米TiO2对Au3+、Pd2+和Rh3+有很强的吸附能力,被用于Au3+、Pd2+和Rh3+分离富集。将该分离富集方法与电感耦合等离子体原子发射光谱法(ICP-AES)相结合建立了测定地质样品中Au、Pd和Rh的新方法。考察了溶液酸度、洗脱条件和干扰离子等因素对分析物的分离富集影响。结果表明,在pH 4.0,Au3+、Pd2+和Rh3+可被改性纳米TiO2定量富集,吸附率在95%以上;而K+、Na+、Ca2+、Mg2+、Zn2+、Ni 2+、Ba2+、Co2+、Cd2+和Mn2+不被吸附,Fe2+、In3+和Ga3+部分被吸附,但对测定没有影响。吸附的贵金属离子可用20g/L CS(NH2)2和2mol/L HCl溶液完全洗脱。在优化的实验条件下,吸附剂对Au3+、Pd2+和Rh3+的吸附容量分别为21.63mg/g,12.82mg/g和19.56mg/g。本法对Au3+、Pd2+和Rh3+的检出限(3σ)分别为:0.61ng/mL,0.58ng/mL和1.89ng/mL,样品测定结果的相对标准偏差(RSD)分别为1.7%,2.6%和1.8(n=11)。该法应用于标准样品(GBW07293)中Au3+、Pd2+和Rh3+的测定,测定值与认定值相符。

The nano-TiO2 was modified with diphenylsulfourea. The modified nano-TiO2 exhibited strong adsorption capacity to Au^3＋ , Pd^2＋ and Rh^3＋ , so it was applied to the separation and enrichment of Au^3＋ , Pd^2＋ and Rh^3＋. This separation and enrichment method was combined with inductively coupled plasma atomic emission spectrometry （ICP-AES） to establish a new determination method for Au, Pd and Ph in geological samples. The effect of solution acidity, elution conditions and interference ions on the separation and enrichment of analyte was investigated. The result showed that Aua^＋ , Pd^2＋ and Rh^3＋ could be quantitatively enriched by modified nano-TiO2 at pH 4.0, while K^＋ , Na^＋ , Ca^2＋ ,Mg^2＋ , Zn^2＋ , Ni^2＋, Ba^2＋ , Co^2＋ , Cd^2＋ and Mn^2＋ were not adsorbed. Although Fe^2＋ , In^3＋ and Ga^3＋ were partially adsorbed, they had no influence on the determination. The adsorbed precious metal ions could be fully eluted with 20 g/L CS（NH2）2 and 2 mol/L HC1. Under the optimized experimental conditions, the adsorption capacity of adsorbent to Au^3＋, Pd^2＋ and Rha^＋ was 21. 63 mg/g, 12.82 mg/g and 19.56 mg/g, respectively. The detection limit （30） for Au^3＋ , Pd^2＋ and Rh^3＋ was 0. 61 ng/mL, 0.58 ng/mL and 1.89 ng/mL, respectiveIy. The relative standard deviation （RSD, n=11） was 1.7 %, 2.6 % and 1.8 %, respectively. The proposed method was applied to the determination of Au^3＋ , Pd^2＋ and Rh^3＋ in reference material （GBW07293）. The found results were consistent with the certified values.