Iron-Based Catalysts Derived from Iron-Containing Sludge for Enhanced Catalytic Performance of H 2 S Selective Catalytic Oxidation.

In this work, iron-containing sludge is used to prepare iron-based catalysts for efficient H 2 S selective catalytic oxidation. First, the effect of calcination temperatures on the catalytic activities of H 2 S 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 H 2 S selective oxidation. Next, various characterization methods are used to analyze the structure and physical-chemical of the sludge-based catalysts. N 2 -Brunauer-Emmett-Teller (N 2 -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 S ext / S micro (17.98) with bigger external specific surface area (49.09 m 2 ·g -1 ), a higher proportion of Fe 3+ species (50.88%), and surface adsorbed oxygen species (48.07%). Meanwhile, O 2 -TPD and CO 2 -TPD analysis indicates that the S-500(2.0) catalyst has a bigger value of the O ads /O Total ratio (50.56%) and (CO 2 ) (weak+moderate) /(CO 2 ) Total ratio of (31.41%), indicating that there are much more oxygen vacancies and weak alkaline sites. As a result, the excellent catalytic performance of H 2 S selective oxidation can be attributed to its outstanding physical-chemical properties.