Coupling catalytic hydrolysis and oxidation for CS2 removal.

CS2 removal was obtained by coupling catalytic hyidation on bi-functional catalyst. On the hydrolysis active sites, CS2 is hydrolyzed to H2S, while on the oxidation active sites, H2S is oxidized to elemental S or sulfuric acid deposited on the porous support. The above process can be expressed as follows: CS2 -->(H2O)COS -->(H2O) -->H2S -->(O2)--> S/SO4(2-). H2S oxidation eliminates its prohibition on CS2 hydrolysis so that the rate of coupling removal CS2 is 5 times higher than that of CS2 hydrolysis. The same active energy of hydrolysis and coupling reaction also indicates that H2S oxidation does not change the reaction mechanism of CS2 hydrolysis. Temperature has obvious effect on the process while the mole ratio of O2 concentration to CS2 concentration (O/S) does not, especially in excess of 2.5. The formation of sulfuric acid on the catalyst surface poisons hydrolysis active sites and causes the decrease of left OH(-1) concentration on the catalysts surface. Lower temperature is suggested for this bi-functional catalyst owing to the low yield ratio of S/SO4(2-).