Iron-Based Catalysts Derived from Iron-Containing Sludge for Enhanced Catalytic Performance of HS Selective Catalytic Oxidation.

In this work, iron-containing sludge is used to prepare iron-based catalysts for efficient HS selective catalytic oxidation. First, the effect of calcination temperatures on the catalytic activities of HS selective oxidation is carried out and it can be found that S-500 calcined at 500 °C performs excellent catalytic activity. Then, the catalytic performance of the S-500 catalyst is further optimized using alkaline treatment with different concentrations of NaOH solution. The results indicate that S-500(2.0) treated with 2 M NaOH solution has the highest catalytic activity of HS selective oxidation. Next, various characterization methods are used to analyze the structure and physical-chemical of the sludge-based catalysts. N-Brunauer-Emmett-Teller (N-BET) and X-ray photoelectron spectroscopy analyses show that the S-500(2.0) catalyst has the smallest average particle (11.17 nm), the biggest ratio of / (17.98) with bigger external specific surface area (49.09 m·g), a higher proportion of Fe species (50.88%), and surface adsorbed oxygen species (48.07%). Meanwhile, O-TPD and CO-TPD analysis indicates that the S-500(2.0) catalyst has a bigger value of the O/O ratio (50.56%) and (CO) /(CO) ratio of (31.41%), indicating that there are much more oxygen vacancies and weak alkaline sites. As a result, the excellent catalytic performance of HS selective oxidation can be attributed to its outstanding physical-chemical properties.