钢渣颗粒对水中Cr(VI)的吸附与还原作用

以钢渣颗粒为水处理剂，分析了其组成和结构，研究了钢渣颗粒直接吸附去除水中Cr(VI)的工艺过程及机理. 结果表明，钢渣颗粒在适当的粒度与用量下，经10 min搅拌处理，水中Cr(VI)浓度由200 mg/L降低到0.5 mg/L，达到《污水综合排放标准》(GB8978-1996)的要求. 钢渣颗粒对水中Cr(VI)的吸附符合Langmuir等温吸附过程，对Cr(VI)的饱和吸附量达6.878 mg/g. 化学分析和XPS分析均表明，钢渣颗粒对水中Cr(VI)具有吸附与还原的联合作用，吸附后钢渣颗粒中Cr(III)含量由0.0985%提高到0.39%，而FeO含量由9.20%下降到8.35%. 吸附后钢渣颗粒表面形成了Cr(OH)3，说明钢渣颗粒中FeO充当了还原剂，将水中Cr(VI)吸附于钢渣颗粒表面并还原成了低毒的Cr(OH)3随钢渣颗粒沉降直接从水中去除.

Adsorption and Reduction of Cr(VI) in Aqueous Solution Using Steel Slag Particles

Steel slag particles, the solid waste produced from steelmaking industry, were used to directly remove toxic Cr(VI) in aqueous solution. The physical and chemical properties of steel slag particles were analyzed, and the process and mechanism of direct adsorption and reduction removal of Cr(VI) were studied in detail. The results showed that after 10 min stirring with grinded steel slag particles, the concentration of Cr(VI) was reduced from 200 to 0.5 mg/L, and reached national waste water discharge limits (GB8978-1996). The adsorption of Cr(VI) with steel slag particles followed the Langmuir isothermal adsorption with saturated adsorptive capacity of 6.878 mg/g. Chemical composition and XPS analysis showed that the adsorption of Cr(VI) using steel slag particles had two functions of adsorption and reduction. After adsorbing Cr(VI), the content of Cr(III) in steel slag particles increased from 0.0985% to 0.39%, and the content of FeO decreased from 9.20% to 8.35%. The Cr(OH)3 had covered on the steel slag particles surface adsorbed. The results revealed that the adsorbed Cr(VI) was reduced by reductive FeO to Cr3+ ion which was further deposited as Cr(OH)3 with lower toxicity. The Cr(OH)3 precipitation fixed on steel slag can be rapidly separated from water as steel slag particles deposit.