Phase transformation and crystal growth of gypsum via hydrothermal treatment with high pressure CO2 for Cr(VI) extraction

被引：2

作者：

Zhong, Rui ^{[1
]}

Xu, Zhongxuan ^{[1
]}

Liang, Shujie ^{[1
]}

Li, Jiguang ^{[2
]}

Deng, Hong ^{[1
]}

机构：

[1] South China Univ Technol, Sch Environm & Energy, Guangdong Prov Key Lab Solid Wastes Pollut Contro, Guangzhou 510006, Peoples R China

[2] Beibu Gulf Univ, Guangxi Key Lab Beibu Gulf Marine Biodivers Conse, Qinzhou 535000, Peoples R China

来源：

SURFACES AND INTERFACES | 2022年 / 29卷

关键词：

Gypsum waste; Crystal growth; Chromium; Phase transformation; Resource recycling; HAZARDOUS TRACE-ELEMENTS; WASTE-WATER; RED GYPSUM; CR-VI; CALCIUM; IMMOBILIZATION; CARBONATION; MG(OH)(2); EMISSION; CHROMIUM;

D O I：

10.1016/j.surfin.2022.101768

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Heavy metal-containing gypsum poses a serious threat to the environment. In this work, the Cr(VI) was extracted fully (>= 99.6%) from hazardous Cr(VI)-containing gypsum sludge via hydrothermal treatment with high pressure CO2, and neutral solutions with a high Cr(VI)-concentration can be recovered due to the instability of carbonic acid. It was found that the phase transformation occurred in hydrothermal stage and crystal growth in standing stage were two essential parts for releasing and separating Cr(VI). The crystal growth can be accelerated by decreasing pH or the solid-liquid ratio. Moreover, the form of Cr(VI) species changed and the size of products increased under the acidic and high-pressure environment generated by passing CO2, which repelled the adsorption of Cr(VI). This work would provide an environment-friendly measure to fully extract heavy metals from hazardous gypsum wastes with just water and CO2.

引用

页数：9