Study on surface regulation of sodium ferric silicate photocatalyst and its enhanced Cr(Ⅵ)photoreduction properties
Silicate-based catalysts have become the focus of current research because of their green,low-cost and stable characteristics.Sodium ferric silicate(NaFeSi2O6,SFS)is a chain silicate with simple composition and ability to absorb vis-ible light,which has attracted people's attention.Firstly,the original SFS powder was synthesized by hydrothermal method,and then the microstructure and Fe(Ⅲ)/Fe(Ⅱ)ratio of the SFS surface were regulated by thermal reduction process to pre-pare the optimal modified SFS for Cr(Ⅵ)reduction.It was found that after thermal reduction at 200℃,the specific surface area of SFS-200 was increased by 43%,the pore volume was increased to 0.081 cm3/g,and the proportion of Fe(Ⅱ)was in-creased from 33%to 45%,significantly improving its catalytic reduction activity towards Cr(Ⅵ).Meanwhile,the effects of SFS-200 catalyst dosage,reduction time,oxalic acid promoter dosage,Cr(Ⅵ)concentration,and other factors on catalytic performance were investigated.It was found that Fe(Ⅱ)-C2O4·-was the main active substance in the catalytic system,main-taining the chemical cycle of Fe(Ⅲ)-Fe(Ⅱ)to enhance the efficient photo reduction removal ability of Cr(Ⅵ)by SFS-200.This study provided an effective way to prepare high-performance sodium ferric silicate photocatalyst for Cr(Ⅵ)waste-water purification,which had great potential for application.
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