Strong affinity of mineral dusts for sulfur dioxide and catalytic mechanisms towards acid rain formation

Abstract

Mineral dust is an important arena for acid rain formation. Here, p-DFT calculations were conducted to study SO2 adsorption onto gibbsite and possible catalytic mechanisms for acid rain formation. The obtained results clearly indicated that SO2 is preferentially adsorbed onto mineral dusts instead of staying in the gas phase, and two catalytic paths were then posed. Path A with first hydrolysis and then oxidation is kinetically preferred, where SO2 hydrolysis appeared to be the rate-determining step for all the investigated surfaces. Partially dehydrated gibbsite (100) surface has the lowest reaction barrier, and a second water molecule causes acid rain formation to occur facilely at ambient circumstances.