Study on combined technology of glutathione reduction and alkali solidification of chromium-containing sludge

Abstract

Chromium-containing sludge (CCS) is a solid hazardous waste containing various heavy metals, threatening the human body and the environment. In this study, CCS was solidified/stabilized by a combined method of glutathione (GSH) prereduction of Cr(VI) and alkali-excited blast furnace slag (BFS) preparation of geopolymer/gel. To explore the prospect of glutathione treatment of solid waste and combination with solidification/stabilization technology. The appropriate dosage and initial pH value of GSH were obtained through experiments (the dosage of GSH was 0.5%, and the initial pH value was 1). The preparation parameters (content of alkali activator 13%, modulus of alkali activator 1.7, initial curing temperature 25 ℃, liquid-solid ratio 0.26) and mechanism of geopolymer/gel were studied. GSH pre-reduction technology significantly increases the maximum dosage of CCS in the solidified body, and increases the proportion of heavy metals in the residual state. The solidified product meets landfill requirements and holds promise as a building material. According to XRD, FTIR, SEM-EDS, Geopolymers/gels solidify heavy metals utilizing physical encapsulation, chemical encapsulation, charge balance, and bonding.

Keywords

• Heavy metal
• Chromium
• Glutathione
• Reduction
• Solidification/Stabilization
• Geopolymer