天然闪锌矿矿物学特征与光催化性能

Mineralogical characteristics and photocatalytic properties of natural sphalerite

本文采集了我国19个产地的天然闪锌矿进行矿物学和光催化性能研究。样品皆为立方Zn S结构,化学成分变化较大,其中Fe对闪锌矿中Zn的替代范围为0.235%~14.826%(质量分数,下同),Cd对闪锌矿中Zn的替代范围为0.133%~1.576%。闪锌矿中Fe含量由低到高,导致颜色由浅变深直至呈黑色,半导体禁带宽度由大变小,估算获得天然闪锌矿的禁带宽度范围为3.18~2.28 e V,明显低于纯Zn S禁带宽度3.68 e V,光催化响应均在可见光范围。验证光催化实验结果表明含Fe较低、含Cd较高的天然闪锌矿可见光催化还原降解甲基橙的效果较佳,如可见光下1 g/L闪锌矿样品(含铁4.262%,含镉1.576%)对30 mg/L甲基橙催化反应4 h后的脱色降解率达到82.11%。天然闪锌矿中Fe含量影响着禁带宽度和光响应范围,Cd含量影响着光催化性能,为高附加值开发利用贱金属资源天然闪锌矿提供了科学依据。

All sphalerites from 19 ore deposits were crystallized in cubic phases with various chemical compositions. The substitution of Fe element for Zn ranges from 0.235% to 14.826%, while the substitution of Cd element for Zn ranges from 0.133% to 1.576%. With the change of the Fe element from low to high, the color of natural sphalerite becomes darker and eventually becomes black, and the band gap, which was narrow than pure ZnS, was reduced from 3.18 eV to 2.28 eV, with all response in visible light excitation. The photocatalytic performance indicates that the sample with both lower Fe content and higher Cd content shows the highest activity to degrade Methyl orange （MO）. For example, the degradation of MO （30 mg/L） with efficiency reached 82.11% under visible light irradiation for 4 h by natural sphalerite with Fe 4.262% and Cd 1.576% （1 g/L）. The Fe content in sphalerite contributed to the band gap value and the range of light spectrum responses, while Cd content affected photocatalytic properties. The results obtained by the authors provide the scientific basis for the profitable utilization of base metal resources like natural sphalerite.