Photoinduced Recovery of Gold Using an Inorganic/Organic Hybrid Photocatalyst
Photoinduced Recovery of Gold Using an Inorganic/Organic Hybrid Photocatalyst
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DOI：
10.1021/jp906981q
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发表时间：
2009-11-19
影响因子：
3.7
通讯作者：
Nagano, Masamitsu
中科院分区：
文献类型：
--
作者：
Kida, Tetsuya;Oshima, Ryuji;Nagano, Masamitsu
研究了基于多金属氧酸盐(W10O324-)/表面活性剂(二甲基二十八烷基铵)杂化的两亲性光催化剂从溶液中光回收金。所制备的无机/有机杂化材料在紫外光照射下，成功地将溶解在水中的金离子在两相体系中光还原(波长320 nm)。这导致了金色薄膜的形成，该薄膜由微米级的六方金片组成，在液/液界面具有晶体取向。回收可在环境友好的pH值为3-6的条件下进行。回收率取决于催化剂和牺牲剂(电子供体)的浓度。扫描电子显微镜观察表明，由于催化剂在金表面的优先吸附，对金颗粒的形成起到了形态指导作用。这使得在界面上形成的金核成长为微米级的大颗粒，可以很容易地通过过滤来收集。多金属氧酸盐与表面活性剂的杂化允许催化剂的重复使用。此外，硫醇化合物的加入显著提高了回收率，因为它们在金上的共价吸附和帮助粒子聚集。结果表明，该复合催化剂作为一种新的绿色工艺回收金具有良好的可行性。
Photorecovery of gold from solution using an amphiphilic photocatalyst based on a polyoxometallate (W10O324-)/surfactant (dimethyldioctadecylammonium) hybrid was investigated. The prepared inorganic/organic hybrid dissolved in chloroform successfully photoreduced gold ions dissolved in water in a two-phase system under UV irradiation (lambda > 320 nm). This resulted in the formation of gold colored films consisting of micrometer-sized hexagonal gold sheets with < 111 > crystal orientation at the liquid/liquid interface. The recovery can be performed at environmentally friendly pH values of 3-6. The recovery rate was dependent on the concentrations of the catalyst and a sacrificial agent (electron donor). SEM observations revealed that the catalyst has a morphology directing role in the formation of gold particles due to its preferential adsorption on gold. This makes gold nuclei formed at the interface grow into microsized large particles that can be readily collected via filtration. The hybridization of the polyoxometallate with the surfactant allows for the repeated use of the catalyst. Moreover, the addition of thiol compounds was found to significantly improve the recovery due to their covalent adsorption on gold and assistance with particle aggregation. The results show promising gold recovery feasibility using the hybrid catalyst as a new green process.